Conductivity Ratio Research Articles

Evaluation of boron toxicity in soil and influencing factors: A case study of sodic soils of Panipat, India.

Boron toxicity is an increasingly serious problem leading to soil degradation and vegetation loss in arid and semi-arid environments worldwide. The soils of solonetzic complexes often display this characteristic. This study aimed to investigate the vertical distribution of hot water soluble-boron (hws-B) in the sodic and agricultural soils of Israna block in Haryana, India. The study also examined the influence of various soil variables on hws-B. The samples were collected at six depths to assess the availability of B. Additionally, an assessment was conducted to ascertain the appropriateness of the water sources for irrigation. The findings of our study revealed a notable disparity in the hws-B content between sodic soils and control agricultural soils, with the former exceeding the toxic thresholds. The levels of B available to plants were highest in the upper layers of soil and reduced as the depth increased. A number of variables influenced the water-soluble B content in sodic soils, particularly pH, calcite content, electrical conductivity (EC), organic matter (OM), and calcium-boron ratio (Ca/B). The results indicated that the boron levels in both surface and groundwater were within acceptable limits for irrigation purposes, suggesting that boron toxicity may not be directly attributed to these sources. Our study suggests that sodic soils contain high levels of boron, which can be toxic, and consequently, proper management of these soils is recommended. It is essential to have a comprehensive understanding of boron levels in surface and sub-surface soils, as well as in irrigation water, in order to effectively manage soil and improve crop productivity.

Local-scale variability in packed beds of polyhedral particles: Structural and thermal distribution

Heat transfer in packed beds largely depends on the bed structure, which is strongly linked to particle shape, yet most prior work focuses on spherical particles. This work contributes towards a better understanding of particle shape effect on the local-scale and its variability. Particle beds are generated numerically and steady-state thermal simulations are conducted for 12 different particle shapes and three particle-to-gas conductivity ratios. Voronoi cells are extracted to obtain local cell porosities; distributions are studied statistically. Another crucial parameter, particle-particle contact areas, are evaluated and compared with shapes. Variability in local structure results in varied temperature profiles. Thermal fluctuations are substantially affected by irregular shapes, an effect that increases for highly conductive particles. Notably, the spatial distribution of phases with different conductance has a strong influence on the distribution of local heat flux. Predominantly, these outcomes also indicate the relevancy of including shape parameters in developing reactors or modeling other granular applications.

Biomass‐based crosslinked composite anion exchange membranes using bacterial cellulose template towards enhanced ionic conductivity and alkaline stability

AbstractA balanced relationship among ionic conductivity, mechanical properties and alkaline stability of anion exchange membranes (AEMs) is essential for their practical application in fuel cells. Herein, a porous substrate (BC@LDH) with hierarchical structure was constructed using natural bacterial cellulose (BC) as a template and then in situ grew inorganic hydroxide ion conductor (layered double hydroxide, LDH). The membrane was fabricated via a filling together with sol–gel crosslinking strategy after impregnating an ionomer containing both quaternary ammonium and hydroxyl groups into the porous substrate and then crosslinked by organosiloxane. Due to the synergistic enhancement effect of BC, LDH and cross‐linking, the obtained membrane exhibited a tensile strength of 47.48 MPa that was 88.3% higher than that of the pure ionomer membrane, and showed an ionic conductivity of 70.7 mS cm−1 (80°C) which benefited from the introduction of ionic conductor LDH. More importantly, its alkaline stability was significantly improved and the residual conductivity ratio was still as high as 81.5% even after hot alkali treatment for 580 h. The direct methanol fuel cell assembled with this membrane exhibited a peak power density of 13.6 mW cm−2 with an open‐circuit voltage of 0.72 V, indicating its potential application in biomass‐based AEMs for fuel cells.Highlights Hierarchical porous substrate comprising LDHs anchored BC fiber was prepared. LDH@BC served as a reinforcing substrate and an ion transport medium. The crosslinked membrane showed significantly improved alkaline stability. The membrane had high ionic conductivity and mechanical strength. Providing a new way to design biomass‐based AEMs with high performance.

Thermal Conductivity and Thermal Hall Effect in Dense Electron-Ion Plasma

In this study, we examine thermal conductivity and the thermal Hall effect in electron-ion plasmas relevant to hot neutron stars, white dwarfs, and binary neutron star mergers, focusing on densities found in the outer crusts of neutron stars and the interiors of white dwarfs. We consider plasma consisting of single species of ions, which could be either iron [56]Fe or carbon [12]C nuclei. The temperature range explored is from the melting temperature of the solid T∼109 K up to 1011 K. This covers both degenerate and non-degenerate electron regimes. We find that thermal conductivity increases with density and temperature for which we provide analytical scaling relations valid in different regimes. The impact of magnetic fields on thermal conductivity is also analyzed, showing anisotropy in low-density regions and the presence of the thermal Hall effect characterized by the Righi–Leduc coefficient. The transition froma degenerate to non-degenerate regime is characterized by a minimum ratio of thermal conductivity to temperature, which is analogous to the minimum observed already in the case of electrical conductivity. We provide also formulas fit to our numerical results, which can be used in dissipative magneto-hydrodynamics simulations of warm compact stars.

Simulation method for the operation of magnetic flowmeters

The issues of testing magnetic flowmeters for liquid metal and studies of their metrological characteristics are considered. The existing liquid metal pouring flowmeters are unsuitable for experimental studies of error components, therefore it is necessary to use simulation methods to simulate the operation of magnetic flowmeters. The tests require the liquid metal plants or methods that allow you to examine flowmeters without plants that can reproduce the flow rate in various operating modes. By analogy with the simulation method of water flowmeters research, a simulation method for modeling the operation of magnetic flow meters for liquid metals has been developed. The proposed method estimates the error of magnetic flowmeters in operation mode. The components of the measurement error of flowmeters caused by a violation of the geometry of the primary converter (the size and location of the electrodes, the design of the inductor coils), a change in the hydrodynamic regime, and the temperature dependence of the shunting effect of the pipeline wall are considered. A representation is obtained for the signal of the primary converter in the form of an integral over the inner surface of the pipe from the product of the radial component of the magnetic field and the surface weight function. The expression found can be interpreted as a magnetic flux through an induction coil located on the inner surface of the channel, the turns of which are drawn along the level lines of the surface weight function. This expression can be interpreted as a magnetic flux through an induction coil located on the inner surface of the channel, the coils of which are placed along the lines of the level of the surface weight function. If such a coil is inserted in the flowmeter channel, the time-integrated voltage induced in the coil will be proportional to the voltage generated between the electrodes of the flowmeter. Since the surface weight function depends on the geometry of the channel, the kinematic structure of the flow, the ratio of wall and liquid conductivities, therefore, the metrological characteristics of the flowmeter can be studied by the simulation method when each of the above factors changes individually or together. To do this, it is enough to make an induction coil taking into account the surface weight function that reflects any of the factors under study or their combination. Simulation methods for studying the dependences of magnetic flowmeter signals on the velocity distribution in the channel and the shunting effect of the pipeline wall are considered.

Conceptual groundwater model of the north-eastern flanks of Mount Kenya

Despite serious concerns over declining river flows and prolonged dry spells in the north-eastern region of Mount Kenya and the Ewaso Ng’iro River watershed many aspects of the groundwater system remain unexplored. In particular, the recharge-discharge dynamics of the Ewaso Ng’iro River have not been studied, and no conceptual groundwater model currently links the recharge areas in the high-elevation humid regions to the drier lowlands. This study aims to address this significant knowledge gap by assessing the recharge-discharge dynamics of the Ewaso Ng’iro River and identifying the relevant groundwater subsystems and the main flow paths within the various lava layers constituting the aquifer system. Hydrochemical and stable isotope analyses revealed three distinct subsystems with slightly different chemistries and different recharge zones, all of recent meteoric origin. Groundwater from Mt. Kenya is of the HCO3-Na-Mg-Ca type with no dominant cations, whereas groundwater from the Nyambene Range, the other surrounding volcanic hills in the area, is of the HCO3-Na type. Groundwater in the third subsystem in between is of the HCO3-Mg type and is confined or semi-confined. In this area, carbon-13 analysis showed a strong influence of mantle-derived CO2 on the groundwater chemistry (very high electrical conductivity and left-shifted oxygen-18 ratios). Finally, major ions and stable isotopes (ẟ18O and ẟ2H) confirmed that during the dry season, the river is entirely groundwater-fed, with the Mt. Kenya subsystem contributing half of the maximum river flow rate of 800 l/s.

Evaluation of the Impact of Recycled Distillery Effluent on the Cultivation of Wheat and Sorghum

With increasing global water scarcity, the reuse of treated wastewater for agricultural irrigation offers a promising solution, particularly in arid regions. This study evaluates the impact of distillery wastewater from Kinmen Kaoliang Liquor Inc. (KKL) on the growth of wheat and sorghum in the Kinmen region. The field experiment applied varying proportions of KKL wastewater to assess its effects on soil properties, nutrient distribution, and crop performance. The results showed that wastewater irrigation increased soil concentrations of key nutrients, such as potassium (K), sodium (Na), magnesium (Mg), and phosphorus (P), but also raised the electrical conductivity (EC) and sodium adsorption ratio (SAR) beyond acceptable irrigation standards. K, Mg, Ca, and P primarily accumulated in the stems and grains, while Na was concentrated in the roots. However, higher wastewater concentrations negatively affected soil permeability due to Na accumulation, and elevated salinity levels led to reduced plant biomass. This study concludes that although wastewater irrigation improves nutrient availability, careful management is essential to mitigate salinity risks and ensure sustainable agricultural practices. These findings offer valuable insights into the potential of wastewater reuse in water-scarce regions and provide practical recommendations for managing associated risks.

Semiconductor WO3 thin films deposited by pulsed reactive magnetron sputtering

A pulsed reactive magnetron sputtering system with a tungsten target and a gas mixture of argon and oxygen was investigated as a source for the deposition of semiconductor WO3 thin films on soda lime glass substrates and on the glass with transparent conductive SnO2:F (FTO) electrode. The reactive sputtering process was performed in HiPIMS mode with low pulse repetition frequency fp ≈ 50–100 Hz and short pulse duration in HiPIMS discharge Ton = 100 μs. The second mode investigated was the mid-frequency (MF) magnetron discharge with pulse frequency fp = 40 kHz and pulse length Ton = 15 μs. The plasma parameters were investigated for both HiPIMS and MF modes using the planar RF probe operating at the frequency fprobe = 350 kHz and the grid QCM with biased collector electrode. Ion density ni and tail electron temperature (Te) were determined in both pulsed reactive magnetron sputtering discharge modes with time resolution. The maximum value ni ≈ 5 · 1017 m−3 was found in the reactive HiPIMS mode, and the maximum value ni ≈ 7 · 1016 m−3 was found in the reactive MF (40 kHz) mode. The degree of ionization of sputtered particles in reactive HiPIMS was determined for different values of (QO2) and was found to be in the range of ri ≈ 0.1–0.3. The deposition rate determined by QCM in reactive HiPIMS was practically independent on (QO2), but in the case of reactive MF, the measured deposition rate decreased significantly with increasing (QO2). The WO3 films deposited in both modes have a predominantly monoclinic crystal structure. The light and dark conductivity and the light/dark conductivity ratio (Ld) were measured under dark conditions and UV light illumination. At higher (QO2), the maximum value of Ld ≈ 300 was found for MF deposited WO3 and the maximum value of Ld ≈ 30 was found for HiPIMS deposited WO3. The photoelectrochemical measurement of WO3 deposited on FTO electrodes confirmed the n-type conductivity, and these films functioned as photoanodes in photoelectrochemical cells. MF deposited WO3 films systematically exhibited slightly higher photocurrents than HiPIMS deposited WO3. It was shown that these optimum photocurrents for HiPIMS and MF were found at QO2 ≈ 80 sccm and could not be improved by further increasing of (QO2).

Electrospun green fluorescent-highly anisotropic conductive Janus-type nanoribbon hydrogel array film for multiple stimulus response sensors

A new strategy aimed at significantly enhancing the anisotropic conductivity of hydrogel materials, along with a simple construction technology and design concept, are proposed. Anisotropic conductive hydrogel materials have attracted much attention from researchers in the field of flexible electronics for their inherent excellent properties. However, the anisotropic conductivity of the existing conductive hydrogels is not high and the preparation methods are complex. Herein, fluorescent-highly conductive anisotropic Janus-type nanoribbon hydrogel array film (named JNHAF) is successfully prepared using a combination of parallel electrospinning and post-polymerization as an example of the study. Highly oriented [2,7-dibromo-9-fluorenone (DF)/gelatin (GE)]//[carbon black (CB)/GE] Janus-type nanoribbon is used as the building block. The composition as well as the arrangement of Janus-type nanoribbons are microscopically designed and regulated to effectively separate the conductive and insulating materials, so that the samples can achieve highly anisotropic conductivity and obvious green fluorescence. When the mass ratio of GE to CB is 1:0.1, the conductive anisotropy ratio of JNHAF can reach 1.12 × 105. The degree of anisotropic conductivity of JNHAF is significantly improved compared with existing reported anisotropic conductive hydrogels, and the preparation method is simple. JNHAF responds quickly to light, tensile strain, and temperature, making it suitable for assembling multi-stimulus responsive sensors. JNHAF has excellent flexibility, degradability, mechanical properties and a certain degree of sensitivity (gauge factor of 4.29), and is used for human joint motion detection with an obvious response signal. The design idea and construction technology of this hydrogel breaks through the technical bottleneck of the low degree of anisotropy of conductive hydrogels, which will lead and expand the scientific frontiers of anisotropic conductive hydrogel materials, and provide novel design ideas and theoretical values for new hydrogel materials.

Thermo-economic performance analysis and multi-objective optimization of viscosity ratio and thermal conductivity ratio of copper oxide–palm oil nanolubricants

Through experimental research, this work explores the thermophysical properties, cooling efficiency, and economic viability of copper oxide–palm oil nanolubricants in tribology applications. The viscosity and thermal conductivity of the nanolubricants were tested at three different volume concentrations (0.1, 0.3, and 0.5 vol. %) throughout a temperature range of 30 °C to 80 °C at intervals of 10 °C. Researchers looked attentively at how the viscosity and thermal conductivity ratios of the nanolubricants were affected by temperature and volume concentration. A significant increase in thermal conductivity was noted with increasing concentration and temperature. On the other hand, as temperature increased, viscosity reduced and was dependent on volume concentration. The property enhancement ratio was used to evaluate the nanolubricants' cooling capacity before an economic analysis of their cooling efficacy was conducted. Based on experimental data, the study led to the creation of novel correlations between the viscosity ratio and thermal conductivity ratio. These models showed a high degree of agreement (R2 values of 99.47% for the thermal conductivity ratio and 97.78% for the viscosity ratio) between the expected and actual outcomes. The ideal values of the viscosity and thermal conductivity ratios were 1.10 and 1.62, respectively. These values corresponded to a critical temperature of 37.32 °C and a volume concentration of 0.16 vol. % for nanoadditives. The findings offer valuable insights into optimizing nanolubricants for enhanced cooling performance in tribological systems, with potential applications in improving energy efficiency and reducing operational costs in industrial processes.

PERFORMANCE OF FREE WATER SURFACE FLOW CONSTRUCTED WETLAND FOR LEAD AND CADMIUM IONS REMOVAL USING AZOLLA PINNATA PLANT

Phytoremediation is the ability of some plants to bio accumulate, decompose, or transformation of pollutants in soils, water, or air. In the current study, an effort is made to study the effectiveness of free-floating plants to treat simulated industrial wastewater polluted with Lead and Cadmium ions using Azolla Pinnata plant in a lab condition. Free water surface flow constructed wetland were fed with simulated Cd and Pb ions in different concentrations (5, 10 and 20) mgl-1. Different operating conditions were studied such as; pH, dissolved oxygen, electrical conductivity, temperature, and sodium adsorption ratio to find out the possibility of using treated wastewater for irrigation. Results showed that, Azolla plant had a higher removal efficiency to extract Lead ions (90.1%, 86.67%, and 81.3%) than Cadmium (79.3%, 78.4%, and 69.7%) when the initial concentration is (5, 10, 20) mgl-1 respectively, during 5 days. A slight reducing in pH (8.3 to 7.4) and dissolved oxygen (8.7 to 7.2) mgl-1 observed, all these values mentioned satisfied with the Iraqi standards and World Health Organization. From values of electrical conductivities (250- 750) (µScm-1) and the sodium adsorption ratios (0- 10) it was found that treated wastewater falls into class C2S1 which mean that water has good quality and can be used to irrigate moderately salt-tolerant crops on soils with good permeability.

A two-dimensional numerical characterization on the droplet dynamics in the electric field by VOSET method

A coupled volume-of-fluid and level set (VOSET) model is extended to the simulation of electro-hydrodynamic (EHD) flow. The good accuracy of proposed model is validated by comparing with previous results. Although the electrostrictive force might be greater than the Coulomb and dielectric forces under certain conditions, it has no influence on droplet dynamic behaviors except the pressure distribution. The electro-coalescence of droplet pair is systematically investigated. In addition to the coalescence and repulsion, two droplets might neither coalesce nor repulse with the repulsive hydrodynamic force and attractive electric force strike a balance. The electro-coalescence of two droplets always happens as long as the electric conductivity ratio is smaller than the permittivity ratio. The critical permittivity ratio separating the coalescence and repulsion of droplets increases as the increase of electric conductivity ratio. The electro-coalescence time of two droplets decreases as the permittivity ratio and electric capillary number increase. Nevertheless, the electro-coalescence time shows different variation tendency as the increase of electric conductivity ratio with different permittivity ratios and electric capillary numbers.

Both edge substitution effects on thermal conductivity of armchair graphene nanoribbons under tensile strain: From equilibrium molecular dynamics simulations

Thermal conductivity and phonon spectra change of graphene nanoribbon as function of both side edges substitution and strain is investigated using equilibrium molecular dynamics. Under small strain, the edge’s partial substitution by graphane plays effect role to change the phonon mode of GNR. Under large tensile strain, reduction ratio of thermal conductivity is the largest in case of fluorographane hybrid and the smallest in case of graphane hybrid. Especially, under 16 % strain, the thermal conductivity of GNR is reduced until 13 % by edges substitution of graphane. The phonon spectra shift peaks towards low frequency at high frequency range (>50 THz).

Two-Dimensional MoS2-Based Anisotropic Synaptic Transistor for Neuromorphic Computing by Localized Electron Beam Irradiation.

Neuromorphic computing, a promising solution to the von Neumann bottleneck, is paving the way for the development of next-generation computing and sensing systems. Axon-multisynapse systems enable the execution of sophisticated tasks, making them not only desirable but essential for future applications in this field. Anisotropic materials, which have different properties in different directions, are being used to create artificial synapses that can mimic the functions of biological axon-multisynapse systems. However, the restricted variety and unadjustable conductive ratio limit their applications. Here, it is shown that anisotropic artificial synapses can be achieved on isotropic materials with externally localized doping via electron beam irradiation (EBI) and purposefully induced trap sites. By employing the synapses along different directions, artificial neural networks (ANNs) are constructed to accomplish variable neuromorphic tasks with optimized performance. The localized doping method expands the axon-multisynapse device family, illustrating that this approach has tremendous potentials in next-generation computing and sensing systems.

Analysis of thermal performance and irreversibility of double-diffusive buoyancy-driven nano-suspension subject to local thermal non-equilibrium model

In fact, local thermal equilibrium (LTE) would be unsuitable when it comes to nuclear reactors, electronic equipment, space devices, geothermal engineering, and high-conductivity foams, due to prominent temperature discrepancy between the two constituents (solid and nanofluid) in porous material. Local thermal non-equilibrium (LTNE) situation may be considered in above real world applications. In view of above relevance, the effects of LTNE model on double-diffusive natural convection (DDNC) within a fluid-saturated porous container loaded with the TiO2-H2O nanofluid and emplacing four cooling and hot channels in Forchheimer-Brinkman-extended Darcy medium have been investigated in the present study. The momentum, heat and mass equations are solved by finite element method. Irreversibility in the two constituents (nanofluid and solid) of the porous structure has been analyzed. The significant outcomes are that fluid circulations enhance due to rise in porosity of the medium. Fluid friction entropy EnFF,T ameliorates significantly by 1514.16 % and 872.97 % with increase in Rayleigh number and porosity of the medium. It is clear that Nuloc,nf,Nuave,nf, Nuloc,s&Nuave,s enhance significantly with rise of buoyancy and thermal conductivity ratio, interstitial solid/fluid heat transfer coefficient.

Growth, Evapotranspiration, Gas Exchange and Chl a Fluorescence of Ipê-Rosa Seedlings at Different Levels of Water Replacement.

In general, young plants in the establishment phase demonstrate sensitivity to changes in environmental conditions, especially regarding water availability. The effects of the seasonality of biophysical processes on plant physiology can trigger differential responses, even within the same region, making it necessary to conduct studies that characterize the physiological performance of the species at different spatial and temporal scales, making it possible to understand their needs and growth limits under water stress conditions. This paper aimed to evaluate the growth, gas exchange and Chl a fluorescence in ipê-rosa seedlings subjected to levels of water replacement (LWRs) of 100, 75, 50 and 25% in a greenhouse. The morphometric variables of plant height, diameter at stem height, numbers of leaves and leaflets, root length and volume, plant dry mass and leaf area were evaluated. The potential evapotranspiration of seedlings (ETc) was obtained using direct weighing, considering the water replacement of 100% of the mass variation between subsequent days as a reference; the cultivation coefficients (kc) were obtained using the ratio between ETc and the reference evapotranspiration (ETo) obtained by the Penman-Monteith FAO-56 method. Biomass and evapotranspiration data were combined to determine water sensitivity. Diurnal fluxes of gas exchange (net photosynthesis rate, transpiration rate, stomatal conductance, internal and atmospheric carbon ratio, water use efficiency and leaf temperature) and Chl a fluorescence (Fv/Fm, ΦPSII, ETR, Fv'/Fm', NPQ and qL) were evaluated. Water restriction caused reductions of 90.9 and 84.7% in the increase in height and diameter of seedlings subjected to 25% water replacement when compared to seedlings with 100% water replacement. In comparison, biomass accumulation was reduced by 96.9%. The kc values increased throughout the seedling production cycle, ranging from 0.59 to 2.86. Maximum water sensitivity occurred at 50% water replacement, with Ky = 1.62. Maximum carbon assimilation rates occurred in the morning, ranging from 6.11 to 12.50 µmol m-2 s-1. Ipê-rosa seedlings regulate the physiology of growth, gas exchange and Chl a fluorescence depending on the amount of water available, and only 25% of the water replacement in the substrate allows the seedlings to survive.

Progress of Conductivity and Conduction Velocity Measured in Human and Animal Hearts.

Cardiac conduction velocity (CV) is a critical electrophysiological characteristic of the myocardium, representing the speed at which electrical pulses propagate through cardiac tissue. It can be delineated into longitudinal, transverse, and normal components in the myocardium. The CV and its anisotropy ratio are crucial to both normal electrical conduction and myocardial contraction, as well as pathological conditions where it increases the risk of conduction block and reentry. This comprehensive review synthesizes longitudinal and transverse CV values from clinical and experimental studies of human infarct hearts, including findings from the isthmus and outer loop, alongside data derived from animal models. Additionally, we explore the anisotropic ratio of conductivities assessed through both animal and computational models. The review culminates with a synthesis of scientific evidence that guides the selection of CV and its corresponding conductivity in cardiac modeling, particularly emphasizing its application in patient-specific cardiac arrhythmia modeling.

Construction of a Borophene-Based Hybrid Aerogel for Multifunctional Applications.

As a novel approach to pursue high-performance multifunctional materials, the structural design of cutting-edge two-dimensional (2D) materials has ignited substantial interests. Borophene, an emerging member in the realm of 2D materials, exhibits crucial attributes, including high theoretical carrier density, electrical conductivity, magnetism, and high aspect ratio, rendering it highly promising for diverse applications. Yet, the exploration of porous structural configurations of borophene remains untapped. Addressing this gap, our study focuses on the fabrication of a multifunctional borophene hybrid foam (CMB-foam). This hybridization leverages the exceptional multifunctionality of MXene alongside borophene within a three-dimensional porous framework, facilitating reflection and absorption of electromagnetic waves, thereby demonstrating remarkable electromagnetic interference (EMI) shielding capabilities. Moreover, this structural configuration exposes an enlarged surface area, thus shortening the transport pathway for electrolyte ions, leading to an excellent energy storage performance. Additionally, CMB-foam performs well in thermal management and thermal insulation. These findings underscore the potential of borophene-based materials in multifunctional applications and offer valuable insights into further performance explorations in this domain.

Experimental study on thermal insulation mortar with normal bearing capacity and its mesoscopic characteristics analysis

Low strength limits the application potential of thermal insulation concrete in high-temperature underground engineering. However, current research on enhancement methods for thermal insulation concrete is relatively limited, and there is a lack of appropriate evaluation indicators, which results in significant room for improvement in its overall performance. To address this issue, this paper develops a load-bearing and thermal insulation mortar (LBTIM) with both thermal insulation and load-bearing capabilities: based on M20 mortar, low-thermal-conductivity materials (aerogel, coal gangue, fly ash) and reinforcing materials (silica fume, basalt fiber, polypropylene fiber) were added. Orthogonal experiments with 6 factors at 5 levels and 6 factors at 3 levels were designed to investigate the thermal conductivity and uniaxial compressive strength of different material ratios. Subsequently, the "strength-to-thermal conductivity ratio" (RST) was defined, and an intensity-thermal conductivity scatter plot was drawn as an evaluation indicator. Based on the experimental results, the ratio of LBTIM was successfully developed and optimized, and its stability was verified through experimental replication. The optimal ratio of LBTIM was determined as follows: aerogel 0.26 %, silica fume 3.35 %, fly ash 7.06 %, coal gangue 30 %, basalt fiber 0.05 %, and polypropylene fiber 0.45 %. Experimental results showed that its thermal conductivity was approximately 0.8 W/m·K, and its uniaxial compressive strength reached 17 MPa. The strength-to-thermal conductivity ratio was improved by 60.7 % compared to M20 mortar. Furthermore, near-distance imaging and SEM tests revealed the mesoscopic mechanism of LBTIM: the high porosity and the formation of an effective porous shear-resistant structure in LBTIM significantly reduced internal air convection. Combined with the externally added porous materials, this effectively blocked the large heat flow channels within the mortar, thereby significantly reducing the thermal conductivity. Meanwhile, the internal porous shear-resistant structure and the reinforcing fiber materials jointly ensured the good load-bearing capacity and stability of LBTIM, providing an important reference solution for addressing the load-bearing and thermal insulation issues in high-temperature tunnels.

Effects of Contact Loss at Electrolyte/Negative Electrode Interface on Current Density Distribution in Solid-State Batteries

Cyclic volume changes and non-uniform electrodeposition/stripping, among other cycling-induced chemo-mechanical degradation of lithium metal and lithium-alloy solid state batteries, lead to contact loss between the anode and the solid electrolyte separator. Operando experiments have shown accelerated short-circuiting behavior due to contact loss in “anode-free” solid-state batteries. Simulations have shown the relationship between active area fraction and the ratio of effective conductivities in regular-shape active area configurations. Through modeling experiments using imputed active contact area of lithium-metal negative electrode batteries, we quantify the effects of this contact loss. Specifically, we (1) quantify the interfacial resistance due to this contact loss, (2) show non-uniform local current density distribution such that evaluation of what area fraction has current exceeding critical current densities is possible, and (3) show non-uniform reaction distribution at the positive electrode. This work sheds light on the tradeoffs in the design of solid state batteries within the context of contact loss.