Investigation Of Electrical Resistivity Research Articles

Investigation of Electrical Resistivity and Conductivity of a Geological Material (Clay) in Some Parts of Ilorin West Local Government, Kwara State

The cost and availability of electrical components have been a major challenge to Nigerian scientists and engineers. Thus, this study aimed at investigating geological material (clay) to alleviate the challenge facing the field of science and engineering. The study determined the electrical resistivity and conductivity of a geological material from three different locations in Ilorin West Local Government Area, Kwara State: Egbejila, Oko-Erin and Baboko. The samples were sieved, molded into cylindrical form and dried. Thereafter, their electrical properties were determined using electrical method. The resistance of the samples was determined from the voltage-current (V-I) graph. Consequently, the resistivity was determined by using sample’s resistance, area and length. The conductivity was calculated from the reciprocal of resistivity. The electrical resistivity and conductivity of the samples from Egbejila, Oko-Erin and Baboko were 0.0850 Wm and 11.7647 (Wm)-1, 0.0924 Wm and 10.822 (Wm)-1, and 0.0251Wm and 39.841 (Wm)-1 respectively. The result obtained from the study showed that the geological material (clay) can be used as alternative material for industrial (based) resistor, the study further reduced the stress, cost, and non-availability of resistors’ importation and thereby our locally made geological material can be used as a substitute.

Investigation of electrical resistivity for fiber-reinforced coral aggregate concrete

The application of fiber-reinforced coral aggregate concrete (FRCAC) holds importance in alleviating material scarcity for island and reef construction and in enhancing structural performance. Electrical resistivity, a nondestructive metric, can be employed to assess the comprehensive performance of FRCAC. Therefore, FRCAC was prepared by incorporating basalt fibers (BF), basalt fibers (MBF), and steel fibers (SF) into coral aggregate concrete in this study. The influence of fiber content, fiber addition form, curing time, and erosion time on the electrical resistivity of FRCAC (FRCAC-ER) was analyzed. Mechanistic analysis of the differences in FRCAC-ER was conducted by mercury intrusion porosimetry and scanning electron microscopy. A predictive model for FRCAC-ER was established using the multi-objective slime mold optimization support vector regression (MOSMA-SVR) algorithm. Results indicate that the optimal fiber content for single fiber incorporation is 0.05% for BF, 1.5% for MBF, and 1.5% for SF. The optimal content decreases to 1% when hybrid fibers (MBF+BF or SF+BF) are used. The microscopic analysis reveals that excessive fiber content increases porosity, reduces the proportion of harmless and less-harmful pores, and increases the proportion of more-harmful pores. Extending the curing time improves FRCAC-ER. At curing times of 3 and 7 days, FRCAC-ER reaches 70–75% and 80–85% of the 28-day resistivity, respectively. Seawater erosion reduces the erosion coefficient of FRCAC-ER, with a more pronounced decrease as the exposure time lengthens. The MOSMA-SVR predictive model for FRCAC-ER demonstrates superior predictive accuracy, model error distribution, and performance evaluation indicators compared with other models. The SF proportion and the water-binder ratio emerge as the most crucial ingredient parameters, exhibiting a negative correlation. A graphical user interface for FRCAC-ER has been developed to assist researchers in predicting and quantifying FRCAC-ER effectively. This research employs resistivity as a metric to gauge FRCAC performance and enhance its overall capabilities, thereby establishing a foundational framework for reef construction.

Experimental investigation and predictive modeling of compressive strength and electrical resistivity of graphene nanoplatelets modified concrete

Multipurpose cement composites are required for the sustainable development of the construction industry. Incorporation of nanomaterials can produce high-performing and multipurpose cement composites (CC). However, predicting the properties of these composites is challenging due to their complex composite nature and nonlinear behavior. This study investigates the integration of graphene nanoplatelets (GNPs) in concrete to enhance compressive strength and electrical properties. In addition to the experimental study, three machine learning techniques i.e., gene expression programming (GEP), support vector machine (SVM), and random forest regression (RFR), are employed to predict the compressive strength and electrical resistivity of graphene nanoplatelet modified concrete (GrNCC). The experimental results showed that GNP was evenly distributed throughout the matrix, and GrNCC exhibited enhanced compressive strength (CS) and fractional change in resistivity (FCR). GNP concentrations of 0.1% and 0.5% depict strength enhancement of 16.58% and 13.23% respectively. Similarly maximum FCR change of − 13%, and − 12.19% is observed. Moreover, GEP was the most robust ML model with mean R2 values of 0.988 and 0.74 for CS and ER respectively. In addition, SVM has R2 values of 0.93 and 0.71, and RFR shows R2 values of 0.899 and 0.671 for CS and ER respectively. GEP performed 52% and 67.5% better than SVM and RFR for CS, and 34.92% and 35.1% better than SVM and RFR for ER in terms of MAE. Furthermore, sensitivity analysis revealed that graphene content is the most important parameter contributing almost 27.3% and 29.2% for CS and ER respectively, followed by graphene dispersion and water content. Moreover, a graphical user interface (GUI) is made using a model that has been trained to predict the output values based on the input parameters. This simplifies the process and offers a valuable tool for utilizing the model's capabilities in civil engineering.

Investigation of Structural, Magnetic Properties, and Temperature-Dependent Electrical Resistivity of Mg0.5-xCuxZn0.5Fe2O4 Ferrites

Investigation of Structural, Magnetic Properties, and Temperature-Dependent Electrical Resistivity of Mg0.5-xCuxZn0.5Fe2O4 Ferrites

First-principles investigation of thickness-dependent electrical resistivity for low-dimensional interconnects

First-principles investigation of thickness-dependent electrical resistivity for low-dimensional interconnects

Experimental investigation of density, electrical resistivity and DSC of AlNiCoCuZr equiatomic alloy

Equiatomic Al–Ni–Co–Cu–Zr alloy was produced by arc melting. Rapidly quenched rods were prepared by suction casting method. Density, electrical resistivity and thermal analysis of the alloy were investigated experimentally. Basing on X-ray diffraction it was shown that the structure of the alloy consists of two competing solid solutions: BCC-ZrNi2Al (Heusler-type phase) and γ-phase Cu9Al4. In addition, pure cooper and Cu3Al, Cu5Zr7Ni5 intermetallic compounds were determined. Rapid quenching of this alloy leads to the formation of solid solutions based on BCC-ZrNi2Al and high-temperature Cu3Al phase. It is shown that the alloy in crystalline state has a linear density change up to solidus temperature. A region of resistivity decrease with increasing temperature is found out for the first time. The melting process goes in a wide temperature range (above 250 K) where 4 thermal reactions were detected. Density and electrical resistivity changes here non-linearly. In liquid state there are no thermal effects in the alloy and temperature dependencies of density and electrical resistivity can be fitted by linear functions.

Investigation of Time-Dependent Electrical Resistivity and Mechanical Properties of Glass Powder and Fly Ash Additive Mortars

Mineral katkılar, çimento esaslı kompozitlerin bazı özelliklerini iyileştirmek ve çimento miktarını azaltmak için beton karışımında kullanılmaktadır. Kullanılan çimento miktarının azaltılması ile çevre kirliliğinin ve çimento üretimi sırasındaki yüksek maliyetin önüne geçilmesi sağlanmaktadır. Bu kapsamda çimento ile ağırlıkça %10, %20 ve %30 oranlarında yer değiştirilerek Cam Tozu (CT) ve Uçucu Kül (UK) karışıma ilave edilmiştir. Harç numunelerinin hazırlanmasında bağlayıcı olarak CEM I 42.5/R tipi Portland çimentosu, agrega olarak ise 0-4 mm boyutlarında kırma kum kullanılmıştır. Laboratuvar ortamında 40x40x160 mm boyutlarında üretilen numuneler kalıptan çıkarıldıktan sonra, standart kür havuzunda 7, 28, 56, 90 ve 180 gün boyunca 20±2 °C sıcaklıkta kür edilmiştir. Taze haldeki harç numunelerine yayılma, sertleşmiş harç numunelerine ise basınç ve eğilme dayanımı ile elektriksel özdirenç deneyleri yapılmıştır. Deneysel çalışmalar sonucu elde edilen veriler doğrultusunda erken yaşta CT ve UK ilavesinin elektriksel özdirenci düşürdüğünü fakat numune yaşı ilerledikçe artışlar meydana geldiği görülmektedir. 180 günlük elektriksel özdirenç değeri REF numunesinde 0.04223 kΩm iken %30UK numunesinde 0.04755 kΩm, %30 CT numunesinde ise 0,04621 kΩm değerine ulaşmıştır.

Алюмосиликомарганец кешенді қорытпасын балқытуға арналған шикіқұрам материалдарының электрофизикалық қасиеттерін зерттеу

This article presents the effectiveness of the use of a new complex of aluminosilicomanganese ferroalloys as an oxygen-containing agent necessary in the production of steel and special alloys. The aluminum silicomanganese alloy is smelted using manganese ore and high-ash coal. In addition to the low cost of the melt, it provides deep purification of both aluminum, silicon and manganese, as well as low-carbon steels from non-metallic impurities. Aluminum silicomanganese is intended for investigation of electrical resistivity of charge materials for melting. Questions of research of specific electrical resistance of charge materials for the smelting of aluminosilicomanganese, in particular, high-ash coals, are considered. The measurements were carried out in the Tamman laboratory unit on a special combined experimental setup connected via converters. Studies on changes in the electrical conductivity of coal were carried out in the temperature range 25-1500°C at a heating rate of 15 deg/min. The main regularities of the formation of the electrical resistivity of charge materials depending on the temperature are determined. The proposed method of measurement makes it possible to obtain in-depth information about the physicochemical properties of charge materials. High-ash coal "Saryadyr", having a constant specific electrical resistance at high temperatures, can be achieved optimal melting mode

Production and investigation of mechanical properties and electrical resistivity of cement-matrix nanocomposites with graphene oxide and carbon nanotube reinforcements

In this study, two groups of the cement-matrix nanocomposites (CMNC) were produced. The first group was reinforced with either carbon nanotubes (CNT) or graphene oxide (GO), where the equivalent weight% of cement equaled 0.05, 0.1, and 0.15. The second group was reinforced with the hybrid CNT–GO, where the equivalent weight% of cement equaled 0.05 CNT–0.1 GO and 0.1 CNT–0.05 GO. Before producing nanocomposites, the distribution of the nanoreinforcement in water had been investigated using spectrophotometric analysis, scanning electron microscopy, and transmission electron microscopy. The physical and mechanical behaviors of different samples of the produced nanocomposites were evaluated by electrical resistivity and compressive strength tests. The effects of the types and the percentages of the nanoreinforcements on the electrical and mechanical properties of the produced nanocomposites were measured. The results showed that the electrical resistivity of the produced composites decreased with increasing the percentage of CNT, whereas the compressive strength of the cement paste initially increased and then decreased. Also, with increasing the percentage of GO, the compressive strength of the produced composites increased, while the electrical resistivity decreased. Moreover, in comparison with the composites reinforced with either CNT or GO, by using the hybrid reinforcement (CNT/GO), the compression strength increased, while the electrical resistivity decreased.

Charge transport mechanisms and magnetoresistance behavior of La0.6Pr0.1Ca0.3MnO3 manganite

Structural properties and charge conduction mechanisms in La0.6Pr0.1Ca0.3MnO3 (LPCMO) manganite has been studied. Presently studied LPCMO manganite was successfully synthesized by solid state reaction method. Structural studies using X–ray diffraction (XRD) measurement at room temperature confirm single phase orthorhombic unit cell without any impurity. A methodical investigation of electrical resistivity was undertaken, for both, as a function of temperature as well as magnetic field. It is observed that LPCMO sample shows metal to insulator transition at TP as well as low resistivity upturn around 30K. Various models and mechanisms have been studied to verify the charge transport properties for low temperature upturn, metallic behavior as well as insulating/semiconducting behavior. Magnetoresistance (MR) behaviors at different temperatures have been theoretically understood on the basis of contributions from grain and grain boundaries.

Low temperature anomalies and room temperature magnetism in In0.95Fe0.05Sb dilute magnetic semiconducting film

We report the results of structural, electrical, surface morphological, and magnetic studies on the undoped and dilute Fe (0.05) doped InSb films (In0.95Fe0.05Sb) using the grazing angle X-ray diffraction technique, the quantum design physical property measurement system, atomic force microscopy (AFM), magnetic force microscopy (MFM), and the quantum design magnetic property measurement system. The In0.95Fe0.05Sb film of 500 nm thickness is grown on the silicon (Si) substrate using the thermal evaporation technique. A systematic investigation of electrical resistivity as a function of temperature and magnetic field is embarked. The electrical resistivity of the respective sample exhibits an upturn at approximately 15 K in the ferrimagnetic region. This theory explains the anomalous behavior of the electrical resistivity based on electron-electron, electron-phonon, electron-magnon, and Kondo-like spin-dependent scattering. The high-temperature data above 300 K are interpreted using the adiabatic small polaron hopping model. The AFM study shows the uniform particle size distribution, whereas the magnetic interaction at the surface is seen through MFM. The zero-field cooled magnetization measurement shows the transition at ∼65 K. The hysteresis curve at 10 K shows the ferrimagnetic behavior of the In0.95Fe0.05Sb film with coercivity and residual magnetization values of ∼100 Oe and 6.8811 emu, respectively.

Tunability of localization length in naphthalene sulfonic acid doped polyaniline/nickel ferrite composite nanorods system

Tunability of key length scales including nanodimensionality, mean free path, localization length, and cyclotron radius gives opportunities to fabricate nanodevices with new functionalities. Herein, in order to tune localization length, composite nanorods (CNRs) of 2-naphthalene sulfonic acid doped polyaniline (PANI-NSA) and nickel ferrite nanoparticles (NiFe2O4 NPs) are synthesized via an in situ chemical polymerization method. The nanorods’ structure and the incorporation of the NiFe2O4 NPs into the PANI-NSA matrix are envisaged by various characterization techniques. The presence of a hysteresis loop with minor coercivity and remanence suggests the ferrimagnetic property of PANI-NSA/NiFe2O4 CNRs at room temperature. Investigation of electrical resistivity as a function of temperature in the absence of an external magnetic field establishes quasi-one-dimensional variable range hopping conduction mechanism of the PANI-NSA/NiFe2O4 CNR samples. CNR samples with two different loadings of NiFe2O4 NPs demonstrate substantial amounts of magnetoresistance (MR) at all the temperatures (300–50 K) studied. Intriguingly, a transition from positive to negative MR is observed with an increase in temperature from 200 to 300 K for CNR samples with less amount of NiFe2O4 (CNRs 1), whereas MR is positive for CNRs with higher loading of NiFe2O4, throughout the studied temperatures. Positive and negative MR behaviors of the CNR samples are quantitatively elucidated in terms of wave function shrinkage and forward interference models. Deduced localization length from the forward interference regime for CNRs 1 is about one order of magnitude larger than that in the wave function shrinkage regime. Thus, tuning of localization length can be achieved qualitatively through appropriate loading of NiFe2O4 NPs.

Influence of Chromium Doping on Electrical and Magnetic Behavior of Nd0.5Sr0.5MnO3 System

With a view to understand the influence of chromium doping at the Mn site on the electrical and magnetic behavior of the Nd0.5Sr0.5MnO3 manganite system, a series of samples were prepared by the citrate sol–gel route method. The samples were characterized structurally by XRD. A systematic investigation of electrical resistivity over a temperature range 5–300 K was carried out mainly to understand the magneto-transport behavior in these materials. Studies on the variation of magnetization with temperature over a temperature range 80–330 K were undertaken. Investigation of magnetization at different magnetic fields at two different temperatures, viz. 80 and 300 K, was also carried out. The results show that chromium doping gave typical electrical and magnetic properties. It has been concluded that the coexistence of charge ordered and ferromagnetic phases induced by chromium doping plays an important role in the low-temperature behavior of the system.

Investigation of Electrical Resistivity of Ni-Cr-Al Alloys in Liquid and Solid State

The subject of the study was temperature dependence of electrical resistivity of alloys based on Ni-Cr-Al system in liquid and solid state. Objects of research were alloy compositions contained 10 and 15 % of chromium and alloyed by 5 and 10 % of aluminium each. The temperature dependences of electrical resistivity was a characteristic to commercial superalloys. It has been founded that the higher the amount of alloyed elements the lower critical temperature heating up to which leads to the formation of equilibrity and microhomogeneouty of the melt structure and the lower the temperature of hysteresis of electrical resistivity polyterms. Melt state before crystallization has had a significant influence on solidification process and structure of alloys in solid state.

Discrete Element Method Investigation of Bulk Density and Electrical Resistivity of Calcined Coke Mixes

Packing density and electrical resistivity of particles assemblies are important factors for a variety of applications of granular materials. In the present work, a three-dimensional imaging technique is coupled with the discrete element method (DEM) to model anode grade calcined coke particles. Three-dimensional DEM models of samples with different size distribution of particles were studied to obtain the inter-particle contact information. As the content of fine particles increased, a higher inter-particle contact density and smaller average contact radius was observed in the samples. Confronting the DEM data and experimental measurements of electrical resistivity showed the simultaneous effects of packing density and contact density. Samples with higher contact density and smaller contact radius in general held high electrical resistivities. However, if increasing the contact density does not modify contacts between large particles, this will have a positive effect on packing density, so a lower electrical resistivity was obtained.

Anomalous magnetoresistance in nanocrystalline gadolinium at low temperatures

The results of a detailed investigation of electrical resistivity, ρ(T) and transverse magnetoresistance (MR) in nanocrystalline Gd samples with an average grain size d = 12 nm and 18 nm reveal the following. Besides a major contribution to the residual resistivity, ρr(0), arising from the scattering of conduction electrons from grain surfaces/interfaces/boundaries (which increases drastically as the average grain size decreases, as expected), coherent electron–magnon scattering makes a small contribution to ρr(0), which gets progressively suppressed as the applied magnetic field (H) increases in strength. At low temperatures (T ≲ 40 K) and fields (H = 0 and H = 5 kOe), ρH(T) varies as T3/2 with a change in slope at T+ ≃ 16.5 K. As the field increases beyond 5 kOe, the T3/2 variation of ρH(T) at low temperatures (T ≲ 40 K) changes over to the T2 variation and a slight change in the slope dρH/dT2 at T+(H) disappears at H ⩾ 20 kOe. The electron–electron scattering (Fermi liquid) contribution to the T2 term, if present, is completely swamped by the coherent electron–magnon scattering contribution. As a function of temperature, (negative) MR goes through a dip at a temperature Tmin ≃ T+, which increases with H as H2/3. MR at Tmin also increases in magnitude with H and attains a value as large as ∼15% (17%) for d = 12 nm (18 nm) at H = 90 kOe. This value is roughly five times greater than that reported earlier for crystalline Gd at Tmin ≃ 100 K. Unusually large MR results from an anomalous softening of magnon modes at T ≃ Tmin ≈ 20 K. In the light of our previous magnetization and specific heat results, we show that all the above observations, including the H2/3 dependence of Tmin (with Tmin(H) identified as the Bose–Einstein condensation (BEC) transition temperature, TBEC(H)), are the manifestations of the BEC of magnons at temperatures T ⩽ TBEC. Contrasted with crystalline Gd, which behaves as a three-dimensional (3D) pure uniaxial dipolar ferromagnet in the asymptotic critical region, ρH=0(T) of nanocrystalline Gd, in the critical region near the ferromagnetic-paramagnetic phase transition, is better described by the model proposed for a 3D random uniaxial dipolar ferromagnet.

Characterization and Low Temperature Study of Iron Telluride Thin Films Upon Ageing and Oxygen Ion Irradiation

The occurrence of superconductivity in iron telluride thin films has been observed upon ageing. The superconducting transition is found to be very robust under an application of magnetic fields up to 10 T. Infrared and Raman spectroscopic characterization of the aged films reveal the formation of Fe1+δTeO x upon ageing. As an alternative method of introducing oxygen in FeTe thin film, oxygen ion irradiation has also been carried out It is found that the irradiated film becomes increasingly disordered and ultimately transforms to an amorphous phase upon increasing the irradiation dose. Investigation of electrical resistivity and optical reflectivity of the irradiated FeTe films indicates an interesting possibility of an ion irradiationinduced phase change memory material in analogy to the phase change characteristics of laserirradiated FeTe films.

Spin-Polarized and Normal Hopping Magnetoresistance in Heavily Doped Silicon

Investigation of electrical resistivity ρ and magnetoresistance in single crystalline n-type silicon heavily doped with antimony in the temperature range ∆T = 5−300 K and at the magnetic inductance B up to 8 T was performed. It was established that, for the temperature range ∆T = 25−300 K the conductivity is of activation type, while for ∆T = 5−25 K it is of variable range hopping and is described by the Mott law. Parameters of the Mott hopping were calculated. It was shown that, to explain the experimental data, the spin polarized hopping via the occupied states has to be taken into account. The obtained parameters revealed that for the low temperature range ∆T = 5−11 K the spin polarized hopping dominates, while for ∆T = 11−20 K the spin polarized transport is accompanied by the wave function contraction.

Electrical Resistivity-Based Study of Self-Sensing Properties for Shape Memory Alloy-Actuated Artificial Muscle

Shape memory alloy (SMA) has great potential to develop light and compact artificial muscle (AM) due to its muscle-like high power-to-weight ratio, flexibility and silent operation properties. In this paper, SMA self-sensing properties are explored and modeled in depth to imitate the integrated muscle-like functions of actuating and self-sensing for SMA-AM based on the investigation of SMA electrical resistivity (ER). Firstly, an ER transformation kinetics model is proposed based on the simulation of SMA differential scanning calorimetry (DSC) curves. Then a series of thermal-electrical-mechanical experiments are carried out to verify the validity of the ER model, whereby the SMA-AM self-sensing function is well established under different stress conditions. Finally the self-sensing capability is further demonstrated by its application to a novel SMA-AM-actuated active ankle-foot orthosis (AAFO).

Investigation of electrical resistivity and magnetotransport properties of the La0.67Ca0.33Mn0.99Fe0.01O3 perovskite oxide

The electrical conductivity and magnetoresistance property of the bulk sample La0.67Ca0.33Mn0.99Fe0.01O3 has been reported, between the magnetic fields 0 and 5T and in temperature range 10–300K. Ferromagnetic metallic resistivity ρFM(T)=ρ0+ρ1Tn is observed well below the metal insulator (MI) transition temperature T<TMI. Above the metal insulator transition T>TMI the electrical conductivity is dominated by the Shklovskii–Efros variable-range hopping mechanism (SE-VRH), giving ρPM(T)=ρohexp[(T0/T)1/2]. Based on the scenario that the doped manganites consists of phase separated ferromagnetic metallic and paramagnetic insulating regions, a good fit of ρ(T) is well described by combining the contribution of ρFM(T) and ρPM(T) by the single expression between the temperature region 33 and 300K. Above TMI the ρ(T) also gives satisfactory fit and is well described using the small polaronic model (SPC) and Mott's VRH. At T≥TMI, a critical behavior of ρ(T) obeys the scaling law ρ−1(T)∼(1−(T/TMI))v. Investigations of magnetoresistance (MR) using magnetic field up to 5T shows two kinds of contribution: one is intrinsic MR and the other is extrinsic MR, which has been accounted fairly well by a phenomenological model based on spin polarized tunneling.