Resistive Layer Research Articles

Влияние горячей пластической деформации на структуру и свойства поверхностно модифицированных слоев после вневакуумной электронно-лучевой наплавки на сталь 12х18н9т с применением порошковой смеси состава 10Cr-30B

Introduction. Currently, austenitic Ni-Cr steels are widely used in the oil and gas industry for drilling wells due to its high corrosion resistance, non-magnetic properties, high impact strength, ductility and weldability. However, in order to increase the service life of products, it is necessary to increase the abrasive resistance of the surface layers while maintaining chemical resistance, which is a difficult technological task. The solution to such a problem can be the creation of sheet blanks “austenitic Ni-Cr steel - modified layer” subjected to hot plastic deformation. The purpose of the work is to study the effect of hot plastic deformation on the structure and phase composition of “modified layer – base metal” compositions obtained by the method of non-vacuum electron beam surfacing of a powder mixture of boron and chromium on austenitic Ni-Cr steel 0.12 C-18 Cr-9 Ni-Ti. Material and methods of research. The work investigated specimens made of steel 0.12 C-18 Cr-9 Ni-Ti with a modified 10Cr-30B layer formed by non-vacuum electron beam surfacing of a powder mixture of chromium and boron, and subsequent hot plastic deformation at a temperature of 950 °C. The research methods are mechanical tests for microhardness, X-ray spectral analysis of the modified layer, metallographic studies, profile analysis, calculation of lattice parameters. Results and discussion. It is revealed that after deformation, defect-free compositions are obtained, the surface layer of which is a matrix composite material containing oriented chromium carbide particles with altered crystal lattice parameters. After plastic deformation, cracks and delamination are not recorded, which allows us to speak about the high quality of the “modified layer – base metal” compositions with increased hardness values exceeding 6.5 times as-delivered steel 0.12 C-18 Cr-9 Ni-Ti (3…11 GPa and 2 GPa, respectively). In the modified layer, complex borides of type (FexCry)B are formed and located in a γ-solid solution of iron. The lattice parameter decreases for γ-iron from 3.588 Å to 3.580 Å, for boride parameter a from 5.126 Å to 5.111 Å, parameter c from 4.228 Å to 4.199 Å.

Geophysical Investigation of Buried Small Fault Beneath Western Mount Malabar Using Electrical Resistivity Tomography in The Great Bandung Basin Rim

This article presents the discovery of a buried fault beneath the soil layers in the Mt Malabar area, which complements the information on suspected faults on the previous geological maps. Using an Electrical Resistivity Tomography (ERT) method, this study aims to delineate the layer discontinuity as a fault and describe the subsurface geology. This study employed a 1400 m long ERT line as the main line to identify buried fault traces, while each ERT line has an 800 m long installation across the main ERT line to obtain the direction of the minor fault. The investigation found a minor fault in the rock layer at a high resistivity layer, approximately 160 m below the surface. The identified rock units are believed to include sandy clay in the upper layer, followed by tuff, sandstone, and basalt lava in the lower layer because its resistivity value is above 250 Ohm.m. The 3D ERT model interpreted a minor buried fault as a weak zone beneath the soil and obtained the fault strike at approximately N 310°E and dipping 66°. Furthermore, these results are strengthened by the geological map, which confirms that ERT L-1 and ERT L-3 profiles coincide with a suspected fault in the Qmt rock unit area.

Synergistic analysis of oxygen transport resistance in polymer electrolyte membrane fuel cells

The oxygen transport resistance of polymer electrolyte membrane fuel cells operated under various conditions (e.g., temperature and relative humidity) was separated into molecular diffusion, Knudsen diffusion, and ionomer film (IF) resistances using the catalyst agglomerate model, dissection of oxygen transport resistance, and distribution of relaxation time analysis. Simultaneously, an analysis of resistance, including charge transfer, proton transfer, and high-frequency resistances, was performed. The Knudsen diffusion resistance of the catalyst layer was calculated by assessing the effects of relative humidity on porosity and pore size. Oxygen transport resistance was analyzed to establish a correlation between temperature, relative humidity, and IF resistance. Water negligibly impacted performance at low oxygen levels at all examined current densities. The fractional contributions of molecular diffusion, Knudsen diffusion, and IF resistances obtained using oxygen transport analysis could be effectively applied to mass transport resistance in the distribution of relaxation time analysis. The IF resistance in the catalyst layer was up to eight times higher than the Knudsen diffusion resistance and 150 times higher than the proton transfer resistance across all current densities, thus most strongly contributing to the catalyst layer resistance. In the gas diffusion layer, the molecular diffusion resistance was up to four times higher than the Knudsen diffusion resistance. Thus, we examined the relationship between the mass transport resistances of individual elements and IF behavior under different operating conditions, revealing that the design of the IF in the catalyst should be considered alongside the relationship between the gas diffusion layer and membrane for optimal performance.

Enhancement in Corrosion Resistance of Low-Carbon Steel via Surface Modification

This research investigated the corrosion resistance of surface layers on low-carbon steel exposed to a chloride environment at room temperature. This study systematically evaluated the effects of varying pack compositions, coating temperatures, and application durations on the characteristics of the deposited coatings. The potentiodynamic polarization corrosion test was employed to assess the wet corrosion behavior of the specimens. Elemental compositions and microstructural features were analyzed using energy-dispersive X-ray spectroscopy (EDX) in conjunction with scanning electron microscopy (SEM), providing insights into phase distribution. The chromizing, titanizing, and chromotitanizing treatments were conducted at temperatures of 900 °C, 1000 °C, and 1100 °C, respectively, with varying coating times. X-ray diffraction analysis revealed a complex arrangement of elements and compounds within the coatings, including Cr, Ti, Cr1.9Ti, FeTi, Al2O3, Cr2O3, TiO2, Cr1.36Fe0.52, and (Ti0.86)3.58. The study found that as the deposition duration increased, the coating thickness increased, comprising a thin inner layer and a substantially thicker outer layer. This layered structure resulted from the outward diffusion of Fe atoms and the inward diffusion of Cr and Ti atoms. Electrochemical analysis in a 3.5% NaCl aqueous solution indicated a marked enhancement in the corrosion resistance of the coated specimens compared to their uncoated counterparts. The potentiodynamic polarization tests confirmed that the protective coatings significantly reduced the corrosion rate, with performance influenced by both the temperature and duration of the deposition process. These findings highlighted the potential of tailored coating techniques to improve the durability and performance of low-carbon steel in corrosive environments.

Effect of discharge thermal action in ECDM on electrochemical behaviours of matrix material and its recast layer in glycol-based solution

The interaction between thermal and electrochemical corrosion in the ECDM process remains unclear. This study clarifies the effect of discharge thermal action on electrochemical corrosion. Real-time temperature curves indicate that the solution temperature in the electrochemical corrosion zone increased significantly due to discharge thermal action. The corrosion resistance of the recast layer’s passive film is superior to that of the matrix due to the enrichment of Cr2O3. As the electrolyte temperature rises, the passive film thickens but shows lower polarization resistances and poorer corrosion resistance due to a loose and weak structure. The matrix material and its recast layer dissolved uniformly, resulting in a considerably flat surface in a glycol-based solution, with enhanced levelling efficiency due to discharge thermal action.

Effect of annealing parameters on the microstructure and tribological properties of FeCoCrNiMn laser cladding layers

The FeCoCrNiMn laser cladding layer exhibits low hardness and poor wear resistance, limiting its applications in the tribology field. The effect of annealing temperature (500 °C-900 °C) and holding time (2 h-14 h) on the properties of FeCoCrNiMn layers which fabricated on the 45# steel substrate were systematically studied. The results demonstrate that the layers' surface hardness and wear resistance initially increase and decrease with increasing annealing temperature and holding time. The FeCoCrNiMn layers subjected to annealing at 700°C for 8h exhibit optimal performance. Specifically, the micro-hardness and wear resistance of the 700°C-8h annealed layers (T700-8) increased by 15.8% and 41.4%, respectively, compared to the substrate. The friction coefficient of T700-8 is 0.635, which is 0.025 lower than that of the substrate. The primary wear mechanisms of the T700-8 are adhesive wear and oxidative wear. Microstructural analysis indicates that annealing at 700°C for 8h forms a Ni-Cr-Fe solid solution phase, strengthening the solid solution. Besides, the average grain size of the layers decreases from 178.7 μm to 115.2μm, indicating grain optimization induced by the annealing process. However, excessively long annealing time or excessively high annealing temperatures lead to the dissolvement of the Ni-Cr-Fe solid solution phase, thus decreasing the surface hardness and wear resistance. Therefore, appropriate annealing parameters can refine the crystal grain, and improve the wear resistance of FeCoCrNiMn layers.

Study on the in-situ generation of hard phases and microstructural and mechanical properties in Ni-WC/W2C cladding layers prepared by TIG arc

Using the principle of in-situ generation, tungsten carbide particles were generated in-situ on 40Cr surfaces pre-coated with self-made powders by TIG arc with flux-cored wires, and the in-situ generation process of hard phases such as WC/W2C was systematically investigated. The macroscopic morphology and microstructure of the cladding layers were analyzed using optical microscopy (OM), scanning electron microscopy (SEM), energy spectrometry (EDS), and X-ray diffractometry (XRD), and the hardness and wear resistance of the cladding layer were tested. The results show that the in-situ grown WC exhibits a positive triangular shape in the two-dimensional plane. No defects such as porosity and cracks are seen in the cladding layer, and the hard phase mainly consists of WC/W2C, as well as carbides with three typical morphologies of dendrites, rods, and ring-block. With the combined effect of residual tungsten carbide particles and in-situ grown hard phase, the optimal hardness and wear volume of the cladding layer were 664.4 HV1 and 0.33 mm3, respectively, which were increased to about 3 and 45 times that of the substrate.

Investigation of the microstructural characteristics of laser-cladded Ti6Al4V titanium alloy and its corrosion behavior in simulated body fluid

Laser cladding technology has a wide range of potential industrial applications in the surface strengthening, repair and reuse of orthopedic implants. By employing this technique to conduct same-material surface restoration and enhancement on titanium alloys, it demonstrates significant developmental potential. However, the microstructure of laser additively manufactured titanium alloy differs significantly from that of traditional titanium alloys, which affects its corrosion resistance in human body fluids. To compare the corrosion resistance differences between the cladding layer and the substrate, this study investigates the microstructure of multi-pass laser cladding Ti6Al4V (TC4) titanium alloy and analyzes the corrosion morphology and corrosion products of the cladding layer in simulated body fluids (SBF). By comparing the electrochemical corrosion behavior of laser cladding with that of traditionally manufactured TC4, this research reveals the differences in corrosion resistance between the two titanium alloys. The research demonstrates that the microstructure of cladding primarily consists of prior-β grains and continuous grain boundary α phase, along with a complex basketweave structure composed of fine acicular α phase and lamellar α phase. Additionally, due to the complex thermal cycling process, the acicular α' colonies within the prior-β grains. These features enhance the cladding layer’s resistance to plastic deformation and increase microhardness, though with some uneven distribution. Interestingly, the TC4 cladding layer forms a porous passivation layer after corrosion, primarily composed of a TiO2 passivation film and deposits of hydroxyapatite and other phosphates. Due to the lower β-phase content, finer grains with higher energy states, and a greater proportion of high-angle grain boundaries (HAGBs) in the cladding layer, it exhibits higher electrochemical activity. As a result of these microstructural differences, the corrosion resistance of the TC4 cladding layer in SBF is inferior to that of TC4 manufactured using traditional techniques.

Highly corrosion-resistant and photocatalytic hybrid coating on AZ31 Mg alloy via plasma electrolytic oxidation with organic-inorganic integration

This study explores the development of an organic-inorganic hybrid coating to enhance the corrosion resistance and photocatalytic properties of AZ31 Mg alloy modified by plasma electrolytic oxidation (PEO). The PEO process typically generates a porous oxide layer, which can reduce corrosion protection by allowing corrosive agents to penetrate the substrate. To address this limitation, phenopyridine (PHEN) and 2-methylimidazole (2-IMD) were incorporated into the PEO surface to form a robust organic layer on the Mg alloy. Potassium hydroxide (KOH) was used to adjust the pH, improving the interaction and solubility between the organic molecules and the PEO coating. The hybrid coating exhibited unique twig-like surface structures that contributed to forming a multifunctional coating with high corrosion resistance and superior photocatalytic activity. The PEO-PHEN-2IMD sample on the Mg alloy demonstrated exceptional corrosion resistance, with the lowest corrosion current density (Icorr) of 1.92 × 10-¹⁰ A/cm², a high corrosion potential (Ecorr), and the highest top layer resistance (Rtop) of 2.57 × 106 Ω·cm², indicating excellent barrier properties. Additionally, the coating achieved complete (100%) degradation of methylene blue (MB) within 30 min under visible light. Density Functional Theory (DFT) calculations provide deeper insights into the bonding mechanisms and interaction stability between PHEN, 2-IMD, and the PEO layer on the Mg alloy and MB dye. These findings confirmed the enhanced performance of the hybrid coating in both corrosion resistance and photocatalytic applications.

Geotechnical and geophysical investigations for infrastructure safety zones: a case study of the supporting ring road, Cairo, Egypt

This study aims to evaluate the suitability of subsurface layers for infrastructure development using geophysical and geotechnical studies. Six seismic refraction and six 2D geoelectic profiles were conducted in the study area to analyze the geotechnical characteristics of the subsoil in order to assess its suitability for construction projects. According to the geophysical investigation, there are two main geoelectric strata, each with a different lithology and thickness. The first layer has high resistivity values of more than 200 (Ωm) and its thickness is between 3.5 and 6.3 m. The second layer's resistivity ranges from 0.3 to 200 (Ωm). The findings indicate that the near-surface area of the study site is composed of two layers in addition to the surface layer, which consists of semi-consolidated wadi fill deposits of gravel, sand, and silt with rock fragments. The first layer comprises fractured limestone with clay intercalation, followed by a second layer of marly limestone, which transitions into marl and clay. Both compressional (P) and shear (S) waves were detected and analyzed. The shallow seismic refraction technique indicates that the velocity waves (Vp) in the first and second layers range from 133 to 770 and 790 to 3100 m/s respectively. Various engineering parameters for the second layer were determined, including elastic moduli (bulk modulus, Poisson’s ratio, rigidity modulus, and Young’s modulus), competence scales (stress ratio, concentration index, material index and density gradient), and bearing capacity (ultimate and allowable). The average Poisson ratio for the first and second layers is 0.235. The ultimate bearing capacity (Qu) of the first layer ranges from 379.1 to 1031.2 gm/cm2 and between 1040.8 and 1548.5 gm/cm2 of the second layer. Allowable bearing capacity (Qall) for the first layer is between 126.4 and 343.7 gm/cm2, and for the second layer, it is between 346.9 and 516.2 gm/cm2. According to the geotechnical investigation's findings, the range of liquid limit (LL) values is between 41.20 and 86.30%, the range of plastic limit (PL) values is between 18 and 35.25%, the range of plasticity index (PI) values is between 14.17 and 51.45%, and the range of free swelling values is between 60 and 170%. However, the study identified high-risk areas in the study area. These zones are located in the first and second layers represented by strongly swelling clay layers and strongly fractured limestone, which will have a major impact on the road and buildings. Therefore, this study recommends addressing these problems before any development to protect these areas from subsidence and collapse.

Integrated geophysical investigations of groundwater for sustainable management in Faisalabad region of Pakistan

As global and local populations surge and climate change continue to disrupt surface and groundwater reservoirs, the urgent need arises to explore additional groundwater sources. Ensuring sustainable management necessitates the efficient identification of high-potential zones to meet escalating water demands. This study aims to delineate groundwater potential zones in Faisalabad District, Pakistan, utilizing a cost-effective geoelectrical resistivity survey method. Apparent resistivity data was collected using the Schlumberger electrode configuration and analyzed with the Interpex “IX1D v2 model” to determine true soil layer resistivities and thicknesses with average root mean square error of 5.12%. The results have revealed that the Aquifer thickness ranged from 13.35 to 165.59 m, and resistivity from 23.96 to 1125.0 Ωm. Hydraulic conductivity, transmissivity, and porosity of aquifers varied from 0.49 to 24.11 m/day (average 8.214 m/day), 35.67 to 1593.98 m2/day (average 567.771 m2/day), and 22.29 to 39.82% (average 37.465%), respectively. Integration of resistivity and geo-hydraulic properties data identified vertical electrical sounding (VES) points 1, 3, 4, and 6 as highly suitable for large-scale freshwater extraction due to having high groundwater potential repositories (coarse sand and gravel formations). Other points had varying suitability: VES points 7 and 8 for shallow wells only, VES points 5, 9, and 10 not recommended due to hard formations, and VES point 2 due to poor groundwater quality. This integrated approach has proven effective in assessing groundwater strata to support Sustainable Development Goal (SDG-3), making it applicable to other geographic locations and informing policy decisions for effective groundwater management.

Geo-electrical investigation for groundwater reserves in the Boranakanive Reservoir Catchment in Tumkur district, Karnataka, India

The groundwater resources have been under significant constraints due to excessive exploitation and climate change. It is imperative to comprehend these dwindling resources' characteristics, given their distribution and occurrence variability across the space and time. A semi-arid climate characterizes the study area and agriculture is the primary occupation, their reliance on groundwater is indispensable due to the lack of surface water sources and erratic rainfall patterns. Consequently, the study employed the Schlumberger array of 200 m-spaced half-current electrodes Vertical Electrical Sounding (VES) survey was conducted at 100 VES locations to identify groundwater potential zones. Further, curve-matching and correlation of lithologies have been carried out from various VES-soundings, and also generated pseudo-cross sections of the subsurface geometry. The results revealed the existence of five geoelectrical resistivity layers as follows layer 1–6 to 422 Ωm, layer 2–8 to 7708 Ωm, layer 3–4 to 37117 Ωm, layer 4–37 to 95059 Ωm, and layer 5–205 to 83142 Ωm. The iso-apparent resistivity maps of the study area reveal values ranging for the first layer 11Ωm - 333 Ωm, the second layer 23Ωm - 5347Ωm, the third layer 11Ωm - 26734Ωm and 10Ωm - 67250Ωm for the fourth layer. The present research determined that the third and fourth layer constitute the principal aquifers due to their fractured structures. As a result, these layers produce a significant quantity of groundwater in the north-eastern (NE) and southern (S) regions of the study region. As a consequence of these findings, further exploration and management of groundwater resources in the study areas can be carried out with valuable insight.

Characteristics of 1D CRL position sensitive SiPM and its performance in acquiring 2D radiation imaging

The characteristics of one-dimensional (1D) position sensitive SiPM with an intrinsic continuous cap resistive layer (CRL) and its performance in acquiring two-dimensional (2D) radiation imaging are reported in this paper. The device, with an active size of 6.14 mm × 6.14 mm, demonstrated the position measurement error of 32.0 ± 24.0 µm without correction, which accounted for 0.5% of the length of the SiPM at a mean response photoelectron number around 230 and the reverse bias voltage of 40 V. Under the same condition, it demonstrated a position resolution of 128.7 ± 20.1 µm and a time resolution of 96.0 ± 33.2 ps. A 3D scintillation detector for acquiring 2D radiation imaging with depth information of interaction (DOI) is proposed by implementing two 1D CRL SiPMs in a perpendicular orientation on the two ends of a scintillator. Using this configuration, the 2D imaging of a pixelated 10 × 10 lutetium yttrium orthosilicate (LYSO) array, with each element having a volume of 0.52 mm × 0.52 mm × 20 mm, was successfully resolved by utilizing the natural radioactive radiation of lutetium element in LYSO without distortions at the edges and corners.

Microstructural and tribological properties of multilayered coatings developed through heat treatment on the surface of CP-Ti

It is well known that applying NiTi intermetallic coatings on the surface of different alloys can improve their tribological behavior. In this paper, various intermetallic phases of Ni3Ti, NiTi, and NiTi2 and a Ti-rich pearlite-like eutectoid structure were in situ synthesized on the surface of commercially pure (CP) titanium grade 2. Nickel electroplating was performed on titanium samples followed by heat treatment at a temperature of 800 °C for various times up to 8 h. The formation of various phases and structures along the depth were studied using SEM, EDS and XRD. Heat treatment at a temperature of 800 °C for 4 h resulted in the formation of a multi-layered composite of Ni3Ti, NiTi, and NiTi2 intermetallic films with a thickness of 5, 9, and 2 μm, respectively. A nickel diffusion layer (NDL) with a pearlitic structure containing nanolayers of αTi-NiTi2 was also formed beneath the NiTi2 layer even after 30 min of heating. Among the different layers formed on the surface of CP-Ti, the titanium-rich NiTi (51–52 at.% Ti) showed the highest hardness of more than 400 HV. Sliding wear tests were performed under a normal load of 10 N and the surfaces of wear tracks were studied using SEM. The results showed higher wear resistance of all intermetallic layers and NDL than the titanium substrate, with the highest wear resistance for Ni3Ti top layer.

Induced polarization in the transient electromagnetic method for detection of subsurface ice on Earth, Mars, and the Moon

The transient electromagnetic method (TEM) can capture an induced polarization (IP) signature of subsurface ice. Using numerical modeling of a horizontally layered earth, we investigate how IP in TEM can be exploited for subsurface ice detection on Earth, Mars, and the Moon. In the model we implement electrical parameters from laboratory measurements of ice, planetary regolith simulants, and terrestrial soil from the literature. In contrast to currently applied forward models, we include two Cole–Cole relaxation terms to model the dielectric relaxation of adsorbed water or salt hydrate in addition to the relaxation of ice. On Earth, IP signals of shallow layers of silt mixed with 44–100 vol% ice embedded in resistive host layers of 3 kΩm can be detected. Both at mid (45∘ N) and lower (35∘ N) latitudes on Mars, meter thick layers of massive ice can be detected at 10 m depth if the ice contains salts. Corresponding layers of 60 vol% ice mixed with Martian regolith simulant show similar detectability. For IP signals of lunar ice to be detected in ice volume fractions of 7.4%–46%, a development in TEM technology is required, including mitigation of early time interference, or enhancing the signal to noise level.

Исследование проницаемости эпителиального слоя клеток TEER методом

The study investigated the electrical characteristics of the Caco-2 cellular layer grown on a cellulose acetate membrane using impedance spectroscopy and cyclic voltammetry methods. The effect of ethanol solutions of varying concentrations on the electrophysical properties of the cellular layer was studied. During measurements of the layer characteristics by the cyclic voltammetry method under direct current, it was found that its resistance before ethanol treatment was 642 kOhm. Treatment with a 25% ethanol solution increased this value to 645 kOhm, while 50% and 95% solutions decreased it to 505 kOhm and 373 kOhm, respectively. During the study of the cellular layer's properties using impedance spectroscopy with alternating current, dependencies of the real and imaginary parts of the resistance on the ethanol concentration in the treatment solution were obtained. The obtained data were used to construct Nyquist diagrams. Their analysis allowed for the proposal of an equivalent circuit describing the process of current flow through the studied system. The equivalent circuit included parameters of paracellular transport, membrane resistance and capacitance, as well as elements accounting for electrode polarization. As a result, values of capacitance and membrane layer resistance were obtained. It was established that the membrane layer capacitance changes under the influence of ethanol. When treated with a 50% ethanol solution, capacitance increases, indicating degradation of the cell membrane and a reduction in its barrier function. Treatment with a 95% solution led to a decrease in capacitance, which can be attributed to the compression of the cell layer, reducing the capacitance contribution to the system's overall conductivity. The results demonstrate the importance of quantitative analysis of cellular electrical parameters for studying their response to chemical stress and confirm the potential of such approaches in biomedicine for creating sensors and «organ-on-a-chip» systems.

Thermal conductivity of snow cover

Important parameters when using snow as a building material and designing the interaction of engineering structures for various purposes with snow are the density and coefficient of thermal conductivity of the snow cover. The purpose of the article was to evaluate the accuracy of calculating the thermal conductivity coefficient of a two-layer snow cover, depending on the degree of compaction of one of the layers. Two approaches to determining the thermal conductivity coefficient are considered: as a layered structure and as an equivalent homogeneous structure having a constant average density. Classical formulas for determining the coefficient of thermal conductivity from density (Abels formula) and density from the depth of snow cover (Abe formula) were used for calculations. As a result of the analysis and complex variant calculations presented in the form of graphs, the following conclusions are made. With a linear dependence of the thermal conductivity coefficient on the density of snow, the choice of one or another method for calculating the thermal conductivity coefficient of a two-layer snow cover does not matter: an error in calculations will always be zero. With a nonlinear dependence of the thermal conductivity coefficient on the density of snow, the error increases with an increase in the compaction coefficient of one of the layers. For example, with a compaction coefficient of 1.5, the relative calculation error does not exceed 4%. And with an increase in the compaction coefficient to 3.5, the error increases to 31%. That is, it increases almost 8 times. The analysis of the results allowed us to conclude that when compacting one of the layers by less than 2 times (compaction coefficient k2), the use of the concept of “average density of snow cover” in thermal calculations to determine the thermal resistance of snow cover is quite acceptable. With an increase in the degree of compaction of one of the layers by more than two times, it is necessary to determine the thermal conductivity coefficient of each layer and calculate the total thermal snow cover as the sum of the thermal resistances of the individual layers.

Modeling Borehole Resistivity Logs with Exponentially Graded Multilayered Soil Inversion for Electrical Engineering Applications

In this paper, we present the application of a special soil resistivity model, the Exponentially Graded Multilayered Soil model, to the interpretation of Borehole Resistivity Logging surveys. The model, which was recently introduced by the authors, offers an alternative to the interpretation provided by constant resistivity layer models. The model is applied to synthetic soil surveys as well as to a real survey that is not satisfactorily interpreted using conventional models. This model aids in the design and calculation of grounding systems in electrical engineering, providing an alternative to calculations performed by traditional layered models.

Surface-Reconstructed CdNNi3 Antiperovskite Electrocatalyst: Unlocking Ampere-Level Current Density for Hydrogen Evolution.

Developing conductive electrocatalysts is crucial for decreasing the ohmic loss induced by electric resistance of the catalyst layer in the large-current-density hydrogen evolution reaction (HER), which has been overlooked previously. In this study, we screen a highly conductive antiperovskite CdNNi3 with negligible ohmic loss, as a highly active and durable HER electrocatalyst capable of unlocking ampere-scale current densities. CdNNi3 exhibits an impressive activity (an overpotential of 235 mV) at 1 A cm-2 and maintains its performance steadily at an ampere-scale current density (at 1 A cm-2 over 400 h). Besides, the CdNNi3-enabled anion-exchange membrane water electrolyzer outperforms that of the benchmark Pt/C, evidenced by a reduced cell voltage of 160 mV at 1 A cm-2, and presents a favorable stability at 1 A cm-2. Importantly, this study experimentally discovers the dynamic surface reconstruction phenomena of antiperovskite nitrides during alkaline HER. Theoretical analysis suggests that the presence of Cd in the reconstructed surface effectively adjusts the local electronic configuration of active sites, which promotes the adsorption of OH and reduces the binding strength to H, thereby facilitating the water dissociation step and reducing the energy barrier of the potential-determining step in the HER process.

SCAPS numerical modeling of CBTS/WO3 thin film solar cell

The quaternary compound Cu2BaSnS4 (CBTS) has emerged as a suitable and attractive light-harvesting material due to its promising optoelectronic features as well as nontoxic and low-cost constituent elements. Yet efficiency of CBTS-based solar cells did not reach the Shockley-Queisser limit. Here, what we believe to be a novel structure ITO/WO3/CBTS heterojunction solar cell is designed and modeled using a solar cell capacitance simulator in one-dimension (SCAPS-1D). In this work, a what we also believe to be a novel WO3 as a buffer layer is proposed for the first time for the efficiency enhancement of CBTS thin film solar cells. Numerical investigation of the performance of CBTS-based solar cells without and with cuprous oxide (Cu2O) back surface field (BSF) is explored. The impact of thickness, doping density, bulk, and interface defect density of an absorber, buffer and window layer, working temperature, shunt and series resistance, back contact work function, and back surface recombination velocity were analyzed and optimized without and with the BSF layer. In this work, the optimized solar cell achieved an efficiency of 18.8%, fill factor (FF) of 83.79%, short-circuit current density (JSC) of 15.99 mA/cm2, and open circuit voltage (VOC) of 1.4 V without Cu2O BSF layer at optimal CBTS absorber and WO3 buffer layer thickness of 2 µm and 0.04 µm respectively. Furthermore, the efficiency boosted to 21.12% with VOC of 1.43 V, JSC of 16.8 mA/cm2 and FF of 87.77% by inserting 0.1 µm Cu2O BSF layer. Therefore, these results will facilitate the fabrication of an efficient and low-cost CBTS-based solar cell with promising WO3 and Cu2O as buffer and BSF layer, respectively.