Variation Of Electrical Conductivity Research Articles

구리/그래핀 복합재의 전기전도도에 미치는 그래핀 입자 및 체적분율의 영향

Cu is most commonly used as a matrix in composites for high electrical and thermal conductivity. Recently, graphene has been researched to improve mechanical and electrical properties as reinforcing materials of composites owing to its excellent physical characteristics. Therefore, the purpose of this study is to evaluate the effects in electrical conductivity according to the shape, structure, and the volume fraction of the graphene reinforcement for Cu/graphene composites. For the evaluation of the variation in electrical conductivity according to the shape and the volume fraction of graphene platelets, RVE was analyzed for models in the location and orientation of graphene which were randomly arranged or not. The change in electrical conductivity of the volume fraction and aspect ratio of graphene platelets was evaluated by using the ABAQUS program. Depending on the angle of graphene platelets, the electrical conductivity was the highest at 0°. In addition, in a relatively high volume fraction model, the electrical conductivity decreased quickly according to increase in the angle, and the variation was changed at angle 45° for the AR.

The properties of the fuel electrode of solid oxide cells under simulated seawater electrolysis

In this study, electrolysis of seawater in flat-tube nickel-yttria-stabilized zirconia (Ni-YSZ) electrode-supported solid oxide electrolysis cells (SOECs) were modeled and the effects of variations in electrical conductivity and microstructure of Ni-YSZ electrode support were investigated. When the current density was greater than 700 mA·cm−2, the conductivity of the electrode support decreased slightly with an increase in current density at 800 °C in hydrogen reduction environment; the conductivity of the electrode support decreased with an increase in the current density when the current density was greater than 400 mA·cm−2 at 800 °C in the seawater electrolysis environment. During long-term durability experiment of seawater electrolysis, the degradation rates in area specific resistance (ASR) were 0.096 mΩ·cm2/100 h and 0.207 mΩ·cm2/100 h with a current density of 300 mA·cm−2 (i.e., ≤400 mA·cm−2) and 1000 mA·cm−2 (i.e., ≥400 mA·cm−2), respectively. Besides, the various ions commonly present in seawater did not contaminate the Ni-YSZ support during the long-term durability test. The degradation mechanism of seawater electrolysis in flat-tube SOECs is discussed and clarified.

Wheat Crop under Waterlogging: Potential Soil and Plant Effects.

Inundation, excessive precipitation, or inadequate field drainage can cause waterlogging of cultivated land. It is anticipated that climate change will increase the frequency, intensity, and unpredictability of flooding events. This stress affects 10-15 million hectares of wheat every year, resulting in 20-50% yield losses. Since this crop greatly sustains a population's food demands, providing ca. 20% of the world's energy and protein diets requirements, it is crucial to understand changes in soil and plant physiology under excess water conditions. Variations in redox potential, pH, nutrient availability, and electrical conductivity of waterlogged soil will be addressed, as well as their impacts in major plant responses, such as root system and plant development. Waterlogging effects at the leaf level will also be addressed, with a particular focus on gas exchanges, photosynthetic pigments, soluble sugars, membrane integrity, lipids, and oxidative stress.

The Influence of Some Factors on the Water Electrical Conductivity Variation Rate in the Low-Frequency Contact Sensors of Conductometers

The aim of the work is to study ways to improve the accuracy of water and steam condensate electrical conductivity measurements by evaluating the effect the parameters of the medium analyzed have on the time constant of the conductometer low-frequency contact sensors. Conductometers are currently among the most widely used and reliable instruments applied in cycle chemistry monitoring systems. The electrical conductivity of process media at thermal and nuclear power plants is measured predominantly with the use of contact low-frequency sensors of conductometers. In this regard, a study of the influence of individual factors on the accuracy of electrical conductivity measurements is a topical and demanded issue. The article presents the results obtained from a study of the effect the sample temperature, flow rate and ionic composition have on the electrical conductivity variation rate in dosing ammonia used for main condensate and feed water correction treatment. A comparative analysis of the obtained dependences of the electrical conductivity time constant on the studied perturbations as applied to low-frequency conductometers of various manufacturers is performed. The experiment conducting procedure and the technical characteristics of the instruments used for electrical conductivity measurements are given. As a result of the accomplished study, the factors affecting the time constant of low-frequency flow conductometers of various manufacturers have been substantiated by experiment, and the accuracy of the obtained measured electrical conductivity values for various sample parameters has been given. The study of the effect the sample qualitative composition has on the conductometer sensor time constant has shown a high variation rate of electrical conductivity values at an ammonia concentration in the medium analyzed up to 300 µg/dm3 followed by a gradual decrease in the conductivity variation rate in the interval up to 1000 µg/dm3. It is shown that the combined dosing of ammonium ions and bicarbonates leads to an increase in the time constant value in comparison with the case of dosing only an aqueous solution of ammonia. Optimal sample parameters (temperature and flow rate) are recommended to obtain more reliable measurements of the process water electrical conductivity at thermal and nuclear power plants.

Two novel phases of germa-graphene: Prediction, electronic and transport applications

In search of potential candidates for thermoelectric energy conversion, graphene and its derivatives always enthralled researchers for their exotic characteristics. Experimental feasibility of germanium (Ge) embedded graphene system (Tripathi et al., ACS Nano 12 (2018) 4641–4647) motivates us to explore prediction and applications of two new phases of germa-graphene structures by employing first-principles calculations in combination with machine-learning approaches. Formal stability analysis reveal that these phases are stable as well as feasible for experimental fabrications. Depending upon Ge concentration, germa-graphene exhibits semi-metallic Dirac cone as well as parabolic dispersions. Further doping-dependent variations in electrical conductivity and Seebeck response enables their applications by securing suitable thermoelectric figure of merit. It is interesting to explore width-dependent rectifying applications of germa-graphene nanoribbons.

Mapping of Soil Physicochemical Properties of Kishtwar District of Jammu and Kashmir (J&K) Using Geographic Information System (GIS)

Objective and Background: A study was carried out to assess and generate the prediction maps of the physicochemical properties of the soil in the Kishtwar district. The Kishtwar district of Jammu and Kashmir covers an area of 7737 sq. km. and falls in the temperate zone of the state. It is an upland valley in the northeast corner of the Jammu region.
 Methods: Soil samples were collected from the entire Kishtwar district in a stratified random manner. The digitization process and generation of maps were carried out with ArcGIS 10.0.
 Results: Sandy loam was the dominant textural class in the district. Soil pH varied widely across the Kishtwar district ranging from as low as 4.87 to as high as 8.00, with a mean value of 6.73. The coefficient of variation CV (coefficient of variation) was 8.08%. Electrical Conductivity (EC) ranged from 0.03 to 9.80 dS m-1 with a mean value of 1.50 dS m-1. The variability of Electrical Conductivity (EC) was high. Organic carbon (OC) ranged from 0.20 to 2.68%, with a mean value of 1.18% with a coefficient of variation (CV) of 48.14%. Calcium carbonate went from traces to 3.60% with a mean value of 0.79% and had a high variability with a CV of 90.38%. Cation exchange capacity (CEC) ranged from 2.50 to 29.40 cmol p+/kg with a mean value of 17.14 and CV of 39.79%.
 Conclusion: Almost all recorded physicochemical properties of Kishtwar district soils were conducive to crop growth. However, the major area of the district was either devoid of cultivation or difficult to cultivate because the region has undulating topography.

Dynamics of lorentz force and cross-diffusion effects on ethylene glycol based hybrid nanofluid flow amidst two parallel plates with variable electrical conductivity: A multiple linear regression analysis

This research investigates how the presence of Dufour and Soret parameters affect the properties of hybrid nanofluid flow amidst two parallel plates with temperature dependent electrical conductivity. Heat transport procedure is studied using thermal radiation parameter and Eckert number. Equations that characterize the current problem are turned into a set of ordinary differential equations, which are then solved with the assistance of a built-in function in MATLAB called the bvp4c solver. Multiple linear regression is used to explain physical parameters of interest including Sherwood number. The main conclusions of this study are that the velocity decreases with increasing nanoparticle volume fraction parameter and the concentration profile minifies with the rise in Soret parameter. It is observed that the increase in Dufour number causes a corresponding increase in the fluid temperature. It is discovered that, when the magnetic field parameter (M) is set to 0≤M≤2.5, the decreasing rate in the skin friction parameter is 0.02215. It is observed that, when φ1 is set to 0≤φ1≤0.25, Nusselt number drops by 3.82891. It is detected that, when Sr is set to 0≤Sr≤2.5, Sherwood number increases at a rate of 0.037225.

Understanding the effect of meat electrical conductivity on Pulsed Electric Field (PEF) process parameters and the ability of PEF to enhance the quality and shorten sous vide processing for beef short ribs

The aim of this research was to investigate how the electrical conductivity of short ribs affected Pulsed Electric Field (PEF) process parameters and the ability of PEF to enhance their quality and reduce sous vide (SV) processing time. Short ribs with different range of electrical conductivity (3–6, 6–9, and 9–12 mS/cm) values were treated using input voltage of 10 kV, pulse width of 20 µs, pulse frequency of 50 Hz and pulse number, of either 1600 (low intensity PEF/LPEF) or 5200 (high intensity PEF/HPEF), followed by SV processing at 60 °C for either 24 or 36 h. The quality parameters assessed were cooking loss (%), Texture Profile Analysis (TPA) parameters, and Commission Internationale d’Eclairage (CIE) L*a*b* colour parameters. There was a variation in electrical conductivity of short ribs according to the position of the bone in the short rib, which demonstrated good congruence with the distribution of fat and connective tissue. SV processing with or without PEF pre-treatment did not have a significant effect (p > 0.05) on cooking loss or CIE L*a*b* colour parameters. Short ribs with a medium conductivity (6–9 mS/cm) had a significantly lower hardness after high intensity PEF followed by SV for 24 h, whilst short ribs with an average conductivity of 3–6 and 9–12 mS/cm required longer SV time (up to 36 h) and had a significantly lower hardness compared to non PEF pre-treated samples. TPA values of short ribs treated with the same PEF intensity and SV processing parameters were comparable regardless of the short ribs initial electrical conductivity, which indicates that PEF treatment could ameliorate the biological electrochemical variability inherent to short ribs and PEF could be the potential tool to decrease their SV processing time and enhance their tenderness.

High thermoelectric properties of shear-exfoliation-derived TiS2-AgSnSe2 nano-composites via ionized impurity scattering

Liquid-assisted shear exfoliation (LASE) has been proved previously to be a facile approach for micro-texture engineering and TE performance optimization for TiS2. Furtherly in this work, ionized impurity scattering was introduced by incorporating 4 mol% nano-AgSnSe2 via LASE. In a specific temperature range of 373–573 K, Seebeck coefficient increased exceptionally in correspondence to an exceptional variation of electrical conductivity with growing temperature, featuring an ionized impurity scattering characteristic and contributing to a record high power factor of 18.2 μW cm−1 K−2 at 573 K in the LASE-derived nanocomposite. Moreover, lattice thermal conductivity was further reduced because of enhanced phonon scattering due to intercalation, impurity, and enhanced grain boundary density. Ultimately, a highest ZT of 0.78 at 673 K as a renewed record for TiS2-based materials was achieved, demonstrating an improved effectiveness of the combination of LASE and ionized impurity scattering in optimization of TE performance of TiS2-like layered TE materials.

Effects of volume and surface conductivity on the surface charge and electric field characteristics of the tri‐post insulator in SF 6 ‐filled ± 500 kV DC‐GIL

Herein, the surface charge characteristics of a tri-post insulator in a ± 500 kV direct current gas-insulated transmission lines (DC-GIL) filled with SF6 are thoroughly studied. The influences of volume and surface conductivity of the insulator on the surface charge and consequent electric field distribution are discussed. An improved method is introduced to obtain the distribution of surface charge with considerable accuracy and efficiency for the calculation. It is found that with increasing the volume conductivity, the dominative conduction mechanism changes from surface conduction to bulk conduction, while the inverse variation appears with increasing the surface conductivity. During the variation of electric conductivity, obvious effect of surface charge accumulation is found on the electric field distribution involving the variation of peak electric field strength and its location. Besides, high charge density usually appears along with low peak field strength during this variation. It can be concluded that the surface charge accumulation should be paid special attention when analysing the insulation characteristics of tri-post insulators. The variation of volume and surface electric conductivity should be thoroughly considered.

Effect of Fe supplantation on structural and dielectric properties of La2CoMnO6

Double Perovskite system La2Co1-xFexMnO6 (x = 0, 0.2, 0.5, 0.8 and 1.0) has been synthesized by sol-gel route. XRD profiles confirmed the absence of any external phase in pure La2CoMnO6 phase. Rietveld refinement analysis confirmed the existence of monoclinic (ordered) as well as rhombohedral and orthorhombic (disordered) structures. Lattice parameters and unit cell volume are found to increase with increase in Fe content. Morphological and compositional analysis was done using FESEM with EDS. Frequency and temperature dependent dielectric characterization revealed the dispersion of both dielectric constant as well as loss tangent at low frequency and high temperature. The Nyquist plot of impedance (cole-cole) revealed negative temperature coefficient of resistance (NTCR) behavior of prepared samples and suggest a non-Debye type relaxation in these samples. An increasing trend with increase in frequency and temperature was exhibited by ac conductivity. Variation of dc electrical conductivity with temperature suggested a semiconducting behavior which can be explained by both small polaron hopping (SPH) and variable range hopping (VRH) conduction mechanisms.

Modelling electrical conductivity variation using a travel time distribution approach in the Duck River catchment, Australia

AbstractSolute dynamics depend strongly on hydrologic flow paths and transit times within catchments. In this paper, we use a travel time tracking method to simulate stream salinity (as measured by electrical conductivity) in the Duck River catchment, NW Tasmania, Australia. The study couples storage selection function transit time modelling with two alternate approaches to model electrical conductivity (EC). The first approach assumes the catchment has a cyclic salt balance (i.e., rainfall source, stream flow sink) that is in dynamic equilibrium and evapoconcentration of salt is the only process changing concentration. The second approach assumes that the salinity of water in catchment storages is a function of water age in those stores, without explicitly simulating salt mass balance processes. The paper compares these alternate approaches in terms of EC simulation performance, simulated stream water age distributions, and simulated storage age distributions. A split sample calibration‐validation analysis was conducted using the 2008 and 2009 water years. Both EC simulation approaches reproduced stream EC variations very well under both calibration and validation. The simulations using the age‐related EC simulation approach produced less biased results and, consequently, higher model coefficient of efficiency for validation periods. This approach also produced more consistent model parameter estimates between periods. There were systematic differences in the resultant age distributions between models, particularly for the solute balance‐based simulations where parameters (catchment storage size) changed more between the two calibration periods. The effect of time varying versus static storage selection functions were compared, with clear evidence that time varying storage selection functions with parameters linked to catchment conditions (flow) are essential for adequate simulation of EC dynamics during flow events.

EFFECTS OF 0.1 WT.% IODINE ADDITIVE ON DIELECTRIC BEHAVIOR AND AC ELECTRICAL CONDUCTIVITY OF POLYETHYLENE OXIDE FILMS

This paper aimed to investigate the electrical characteristics of thin films formed of polyethylene oxide (PEO) distributed with dopants containing a fixed quantity of iodine (0.1 wt.%). The alternating current (AC) electrical properties were studied using the AC impedance technique in the frequency range 3kHz–5MHz and temperature range 30–55oC. The electrically prepared films were made using the casting procedure. This paper compared the variation of AC electrical conductivity with frequency for PEO doped with an iodine-doped polyethylene oxide film and determined some physical quantities and parameters such as AC conductivity, impedance, dielectric constant, and phase angle. The impedance (Z), dielectric constant (e'), dielectric loss (e"), and AC conductivity data observed revealed frequency and temperature. According to polarization processes, the dielectric constant and dielectric loss of the produced thin films increase with doped iodine complexes and decrease with frequency. Iodine, temperature, and frequency all improve AC conductivity.

Parallel Electrical Conductivity at Low and Middle Latitudes in the Topside Ionosphere Derived from CSES-01 Measurements

The study of electrical currents in the topside ionosphere is of great importance, as it may allow a better understanding of the processes involved in the Sun–Earth interaction and magnetosphere–ionosphere–thermosphere coupling, two crucial aspects debated by the Space Weather scientific community. In this context, investigating the electrical conductivity parallel to the geomagnetic field in the topside ionosphere is of primary importance because: (1) it provides information on the capability of the ionosphere to conduct currents; (2) it relates current density and electric field through Ohm’s law; (3) it can help to quantify the dissipation of currents; (4) it is generally modeled and not locally measured by in situ missions. In this work, we used in situ measurements of electron density and temperature recorded between 2019 and 2021 by the China Seismo-Electromagnetic Satellite (CSES-01) flying with an orbital inclination of 97.4° and at an altitude of about 500 km to compute the parallel electrical conductivity in the topside ionosphere at low and middle latitudes at the two fixed local times (LT) characterizing the CSES-01 mission: around 02 and 14 LT. The results, which are discussed in light of previous literature, highlight the dependence of conductivity on latitude and longitude and are compared with those obtained using values both measured by the Swarm B satellite (flying at a similar altitude) and modeled by the International Reference Ionosphere in the same time period. In particular, we found a diurnal variation in parallel electrical conductivity, with a slight hemispheric asymmetry. Daytime features are compatible with Sq and equatorial electrojet current systems, containing “anomalous” low values of conductivity in correspondence with the South Atlantic region that could be physical in nature.

Evaluation of Physicochemical Variables Following Demolition of Building Structures in and Around Kware Lake, Sokoto, Nigeria

Physical and chemical factors are dynamic in nature, and anthropogenic activities can affect these changes. The residents have used Kware Lake as a source of drinking water, irrigation, and fishing activities. The destruction of structural buildings inside and surrounding the lake served as the impetus for this investigation. Selected physicochemical factors were identified, and three study locations (Inlet, Mid, and Outlet) were chosen. For a period of six months, monthly samples of water and sediment were taken (October 2021 to March 2022). The amounts of Ca+ , Mg+ , SO4, and NO3 were found to be significantly changed across months when measured using standard methods, although, Na+ values were not and there was little seasonal variation in electrical conductivity (EC). However, at p<0.05, the variables pH, Biological Oxygen Demand (BOD), Dissolved oxygen (DO), and Ammonia (NH4) indicated a significant difference across months. Additionally, according to a sediment investigation, there were no appreciable variations in electrical conductivity, organic carbon (OC) and clay between the months. However, in February and March of 2022, elevated pH and EC concentrations were observed. To ensure that the Kware residents continue to use the water daily, continuous monitoring is necessary

Comparison and interpretation of freshwater bacterial structure and interactions with organic to nutrient imbalances in restored wetlands.

Chemical oxygen demand to nitrogen (COD/N) and nitrogen to phosphorus (N/P) ratios have distinct effects on bacterial community structure and interactions. However, how organic to nutrient imbalances affect the structure of freshwater bacterial assemblages in restored wetlands remains poorly understood. Here, the composition and dominant taxa of bacterial assemblages in four wetlands [low COD/N and high N/P (LH), low COD/N and low N/P (LL), high COD/N and high N/P (HH), and high COD/N and low N/P (HL)] were investigated. A total of 7,709 operational taxonomic units were identified by high throughput sequencing, and Actinobacteria, Proteobacteria, and Cyanobacteria were the most abundant phyla in the restored wetlands. High COD/N significantly increased bacterial diversity and was negatively correlated with N/P (R2 = 0.128; p = 0.039), and the observed richness (Sobs) indices ranged from 860.77 to 1314.66. The corresponding Chao1 and phylogenetic diversity (PD) values ranged from 1533.42 to 2524.56 and 127.95 to 184.63. Bacterial beta diversity was negatively related to COD/N (R2 = 0.258; p < 0.001). The distribution of bacterial assemblages was mostly driven by variations in ammonia nitrogen (NH4+-N, p < 0.01) and electrical conductivity (EC, p < 0.01), which collectively explained more than 80% of the variation in bacterial assemblages. However, the dominant taxa Proteobacteria, Firmicutes, Cyanobacteria, Bacteroidetes, Verrucomicrobia, Planctomycetes, Chloroflexi, and Deinococcus-Thermus were obviously affected by variation in COD/N and N/P (p < 0.05). The highest node and edge numbers and average degree were observed in the LH group. The co-occurrence networkindicated that LH promoted bacterial network compactness and bacterial interaction consolidation. The relationships between organic to nutrient imbalances and bacterial assemblages may provide a theoretical basis for the empirical management of wetland ecosystems.

Density functional theory investigation of ozone gas uptake by a BeO nanoflake

Due to importance of the gas uptake topic in environment and energy issues, this work was performed for investigating ozone (Oz) gas uptake by means of a beryllium oxide (BeO) nanoflake. To this aim, density functional theory (DFT) calculations and the quantum theory of atoms in molecules (QTAIM) analysis were performed. The monolayer BeO nanoflake was decorated by a HEME-like N4Fe region to prepare an interacting region towards the Oz uptake. Accordingly, three models were optimized based on configurations of Oz molecule relaxation at the BeO surface, in which two types of O ... Fe and O ... N interactions were observed. In this case, Oz3@BeO model was involved with two mentioned types of interactions and three occurred interaction between Oz and BeO making it as the strongest bimolecular formation model of Oz@BeO. Moreover, electronic molecular orbital features indicated that the models formations could be also related to sensor functions by variations of electric conductivity because of Oz gas uptake. As a consequence, the investigated BeO nanoflake of this work was proposed for employing in Oz gas uptake for different purposes.

Oceanic Electrical Conductivity Variability From Observations and Its Budget From an Ocean State Estimate

AbstractBecause spatio‐temporal variations in ocean heat content (OHC) are strongly predicted by ocean conductivity content (OCC) over most of the global ocean, we analyze the dynamical budget and behavior of the electrical conductivity of seawater. To perform these analyses, we use an ocean‐model state estimate designed to accurately represent long‐term variations in ocean properties in a dynamically and kinematically consistent way. We show that this model accurately reproduces the spatio‐temporal variations in electrical conductivity seen in satellite‐derived data and in a seasonal climatology product derived from in‐situ data, justifying use of the model data to perform further analyses. An empirical orthogonal function analysis suggests that the vast majority of the variance in OHC and OCC can be explained by similar mechanisms. The electrical conductivity budget's most important term is the temperature forcing tendency term, suggesting that ocean heat uptake is the mechanism responsible for the strong relationship between OCC and OHC.

Spatio-temporal Variation of Groundwater Level and Electrical Conductivity in Coastal Areas of Jeju Island

Spatio-temporal Variation of Groundwater Level and Electrical Conductivity in Coastal Areas of Jeju Island

Hydrothermal Synthesis of ZnO-Doped Poly-2-(4-Fluorophenyl)-2-Oxoethyl-2-Methylprop-2-Enoate Nanocomposites for Electronic Devices

In our research described here nanocomposites containing a newly synthesized methacrylate polymer, poly 2-(4-fluorophenyl)-2-oxoethyl-2-methylprop-2-enoate (PFPAMA) and ZnO nanoparticles in various mass ratios (1, 3 and 5 w %) were synthesized using the hydrothermal method. The synthesized nanocomposites were characterized by Fourier-transform infrared spectroscopy (FTIR), Hydrogen-1 nuclear magnetic resonance (1H-NMR) and X-ray diffraction (XRD) techniques. Both real and imaginary components of the complex dielectric permittivity of pure PFPAMA and the three different PFPAMA/ZnO nanocomposites were measured as a function of frequency. The dielectric study revealed that the ZnO nanoparticles improved the dielectric properties of pure PFPAMA. The variation of electrical conductivity, with frequency showed that the σ value increased linearly with increasing ZnO content. The frequency dependence of the conductivity suggested that the conduction occurs via a barrier hopping process. The obtained results suggest that the ZnO-doped, poly-2-(4-fluorophenyl)-2-oxoethyl-2-methylprop-2-enoate nanocomposites can be used as a dielectric material in dielectric device applications.