Surface Layer Research Articles

Investigation of the thermal structure in the atmospheric boundary layer during evening transition and the impact of aerosols on radiative cooling

AbstractThe evening transition is crucial in various phenomena, including boundary‐layer stability, temperature inversion, radiation fog, vertical mixing, and pollution dispersion. We have explored this transition using data from 80 days of observations across two fog seasons at the Kempegowda International Airport, Bengaluru (KIAB). Through field experiments and simulations integrating aerosol interaction in a radiation–conduction model, we elucidate the impact of aerosols on longwave cooling of the atmospheric boundary layer (ABL). Field observations indicate that, under calm and clear‐sky conditions, the evening transition typically results in a distinct vertical thermal structure called the lifted temperature minimum (LTM). We observe that the prevailing profile near the surface, post‐sunset is the LTM profile. Additionally, the occurrence of LTM is observed to increase with decreases in downward and upward longwave flux, soil sensible heat flux, wind speed, and turbulent kinetic energy measured at 2 m above ground level (AGL). In such scenarios, the intensity of LTM profiles is governed primarily by the aerosol‐induced longwave heating rate (LHR) within the surface layer. Furthermore, the presence of dense clouds leads to increased downward flux, causing the disappearance of LTM, whereas shallow fog can enhance LTM intensity, as observed in both field observations and simulations. Usually, prevailing radiation models underestimate aerosol‐induced LHR by an order of magnitude compared with actual field observations. We attribute this difference to aerosol‐induced radiation divergence. We show that the impact of aerosol‐induced LHR extends hundreds of meters into the inversion layer, affecting temperature profiles and potentially influencing processes such as fog formation. As the fog layer develops, LHR strengthens at its upper boundary. However, we highlight the difficulty in detecting this cooling using remote instruments such as microwave radiometers.

Lagrangian Stochastic Modeling of Unstable Atmospheric Surface Layer

This study evaluates the performance of a recently developed Lagrangian stochastic model (LSM), which solves the transport equations for turbulence probability density functions (PDFs), for simulating the unstable atmospheric surface layer (ASL). The simulated statistics are compared with the Monin-Obukhov similarity theory (MOST) predictions for mean gradients, standard deviations, turbulent Prandtl number, turbulence kinetic energy budgets, and turbulence PDFs. The LSM successfully captures many aspects of ASL structure and turbulence characteristics, particularly the mean gradients and standard deviations of potential temperature, specific humidity, and vertical velocity, which align closely with MOST predictions. However, the model shows limitations in reproducing the stability dependency of mean gradients of horizontal wind speed. Additionally, the model underestimates the probability of high vertical velocity fluctuations, leading to underprediction of turbulent transport and thermal convection initiation. The simulated turbulent Prandtl number shows dependency on stability but is generally weaker than MOST predictions. The study identifies that the parameterizations of dissipation, pressure redistribution, and pressure transport need to be enhanced to ensure that they have correct stability dependency, in order to improve the model’s accuracy in simulating the ASL.

Exploration and Empirical Study on Spatial Distribution of SOC at the Core Area in Coastal Tamarix Forests’ Inland Side of Changyi National Marine Ecological Area

The forest soil carbon pool plays a vital role in terrestrial ecosystems, being of great significance for maintaining global balance, regulating the global carbon cycle, and facilitating ecological restoration. Shandong Changyi Marine Ecological Special Protection Area is the only state-level marine special protection area in China with tamarisk as the main object of protection, and it is the largest continuous and the best preserved natural tamarisk forest distribution area on the mainland coast of China. Compared to other forested areas, research on the spatial distribution of SOC at the core area in coastal Tamarix forests’ inland side appears to be relatively scarce. Based on this, this paper takes the core area of the Changyi National Marine Ecological Special Protection Zone, located on the southern coast of Laizhou Bay, as the research subject, based on the potassium dichromate oxidation-external heating, one-way ANOVA, and Bonferroni methods, analyzing the spatial distribution of the SOC content inland of coastal Tamarix forests. The research yielded the following conclusions: (1) The surface layer (0–10 cm) contributes significantly to the total SOC content within a 0–60 cm depth, accounting for at least 31% and shows notable surface accumulation. (2) The combined SOC content in the surface and subsurface layers (10–20 cm) accounts for at least 50% of the total SOC content within a 0–60 cm depth, indicating the dominance of these two soil layers in carbon storage. (3) The SOC content decreases with the soil depth at all six sampling points within the 0–60 cm range, with a marked drop from 0–10 cm to 10–20 cm. (4) One-way ANOVA and multiple comparisons reveal that the soil depth significantly affects the SOC distribution, particularly between the surface and 20–30 cm layers (p < 0.001), indicating high robustness and statistical significance. (5) Horizontally, the total SOC at 0 m is 45% lower than at 2 m in the 0–60 cm layer. The SOC in the 0–20 cm layer fluctuates significantly with distance from the shrub trunk, while the SOC in the 30–60 cm layers is low and stable, with minimal variations with depth. In addition, this study found that the SOC content in the core area of the protected area is lower than that in the common forest ecosystem. In the future, scientific ecological restoration projects and management protection methods should be used to improve soil’s carbon storage and carbon sink capacity. These findings not only validate the patterns of SOC’s spatial distribution in coastal Tamarix forest wetlands but also provide a scientific basis for carbon assessment and the formulation of ecological protection measures in coastal wetlands.

Impact of short-term pasture development on soil aggregation, temperature sensitivity of soil organic carbon, and functional diversity in semi-arid ecosystem

Pasture development could be a viable option to restore degraded land in semi-arid region. New knowledge on soil functional diversity, aggregation, and temperature sensitivity (Q 10) of soil organic carbon (SOC) after pasture development would assist to accomplish the scope of global pastureland management for climate change mitigation and land restoration. To understand the impact of pasture development on soil aggregation, SOC stock, and its Q 10, research was undertaken at three development sites (RS1, RS2, RS3) in India with seeding of Cenchrus ciliaris, Megathyrus maximus, and Stylosanthes seabrana (at a line-ratio of 2:2:1). After three years, biomass productivity and for SOC, aggregation, enzyme activities, etc. at 0–20 and 21–40 cm depths were estimated. Pasture development improved biomass productivity from 0.68 mg ha−1 in undeveloped site to 3.62–4.64 mg ha−1. Pasture development enhanced SOC stock from 5.85 to 7.31 mg C ha−1 at the surface layer with an annual accumulation rate of 28–112 kg SOC ha−1 year−1. Greater activities of extracellular enzymes were observed at the surface soil layer in pasture development sites over undeveloped control. The mean weight diameter was ∼23–38% higher at pasture development sites over undeveloped sites. The Q 10 being controlled by the labile carbon was significantly higher (13–29%) at the pasture development sites over undeveloped site. Hence, short-term pasture development could improve the SOC stocks at the surface layer only, but the stocks were vulnerable to C loss at higher temperature. However, long-term pasture development could have a great potential to accrue C to mitigate climate change.

A method introducing deteriorating bond at the interfaces and declining load transfer at the joints in the existing design methods for concrete pavements

Most of the concrete highways of the Belgian road system have a structure composed of a CRCP surface layer, a thin intermediate asphalt bond layer and a lean concrete base layer on one or more granular sub bases. They are designed as an equivalent composite rigid layer on an elastic granular sub grade. The equivalent Young’s modulus of the composite layer is assumed to be equal to the modulus of the concrete surface layer, the thickness is assumed to be equal to the sum of the thickness of the three layers; the equivalent moment of inertia and the equivalent stiffness depend on the values of the thickness and the moduli of each layer and the bond conditions between the layers. Several investigations regularly performed on pavements currently thirty years old have shown a systemic deterioration of the bond between the surface layers and of the load transfer at the cracks of the CRCP or at the joints of concrete slabs. In this paper we present a mathematical model that permits the computation of the influence of this systemic deterioration on the lifetime of the pavements.

Irradiation origin and stability of CO on trans-Neptunian objects. Laboratory constraints and observational evidence from JWST/DiSCo-TNOs

The James Webb Space Telescope large program DiSCo-TNOs has recently shown that CO_2 ice is ubiquitous on 54 medium-size trans-Neptunian objects (TNOs). TNO surfaces are found to define three main spectral and thus compositional groups that are likely linked to their position before planetary migration. CO ice is observed on the spectral type that is richest in CO_2 and on the type that is richer in CH_3OH and organics. Considerations on the thermal evolution of TNOs predicted the depletion of hypervolatiles such as CO from their surface layers, however. We investigate a potential irradiation origin of CO as well as its stability by studying the distribution of CO in two TNO compositional types and compared it with irradiation experiments. We studied the 4.68 μm band of CO and the 2.70 μm band of CO_2 to probe the relation between the two molecules in 33 TNOs. We performed ion irradiation experiments on CO_2 and CH_3OH ices at 45 and 60 K with 30 keV H^+. We compared the laboratory spectra to TNO observations by focusing on the band areas and positions. We find that the two types of surfaces in which CO is detected are very distinct in terms of their relative abundances and chemical environment. CO that is observed on surfaces that are rich in CO_2 are consistent with being produced by CO_2 irradiation, specifically, at 45 K. On objects that are rich in CH_3OH and complex organics, CO is more likely formed by irradiation of CH_3OH. As the CO band areas are only partly related with temperature, the chemical environment plays a major role in the CO retention. We find that the CO that is observed on TNO surfaces is compatible with being a secondary molecule that is entirely formed by late irradiation processes. Its abundance and stability is mostly controlled by the matrix from which it formed.

The Potential of Sitka Spruce Bark as an Alternative to Peat Casing for Mushroom (Agaricus bisporus) Production

White button mushrooms are an important crop globally, and due to the role of peat in current cultivation practices, the industry is under increasing pressure to find suitable alternatives. Peat functions as “casing”, a surface layer that, amongst other functions, provides available water to the fungal mycelium and is considered essential for mushroom growth. This research aimed to determine the potential of bark as an alternative casing material and its suitability for commercial mushroom production. Two experiments were conducted, comparing two types of commercially available peat casing with bark-based casings. The bark casing in Experiment A was found to be statistically similar to the peat casing in terms of yield and quality. The two bark casings in Experiment B failed to produce a 1st flush of mushrooms, and total yields were significantly lower compared to the peat casings, highlighting the fact that the consistency of the bark material across both experiments was variable. There were several issues associated with the bark casing, which included water stress and cropping delays, all of which would be unacceptable from a commercial perspective. Further research is required to refine bark-based casing, focusing on a better consistency of the bark feedstock and reduction of contamination risk. This work contributes to ongoing research and development to address the dependency of mushroom production on peat.

Enhance Oil Recovery in Fracture-Cave Carbonate Reservoirs Using Zwitterion-Anionic Composite Surfactant System

The carbonate fracture-cave reservoir in the Tahe oilfield, China, encounters development challenges because of its substantial burial depth (exceeding 5000 m). Its characteristics are low permeability, pronounced heterogeneity, extensive karst cavern systems, diverse connection configurations, and intricate spatial distribution. Prolonged conventional water flooding leads to predominant water channels, resulting in water channeling and limited sweep efficiency. Surfactant flooding is usually adopted in these conditions because it can mitigate water channeling and enhance sweep efficiency by lowering the interfacial tension (it refers to the force that is generated due to the unbalanced molecular attraction on the liquid surface layer and causes the liquid surface to contract) between oil and water. Nonetheless, the Tahe oilfield is a carbonate reservoir where surfactant is prone to loss near the well, thereby limiting its application. High-pressure injection flooding technology is an innovative method that utilizes injection pressure higher than the formation rupture pressure to alter reservoir permeability, specifically in low-permeability oil fields. Because of the high fluid flow rate, the contact time with the interface is decreased, enabling the ability for surfactants to reach the deep reservoir. In this article, based on the mixed adsorption mechanism of two surfactants and the hydrophilic and lipophilic equilibrium mechanisms, a set of high-temperature and high-salinity resistance surfactant systems appropriate for the Tahe oilfield is developed and its associated performance is evaluated. An oil displacement experiment is carried out to examine the effect of surfactant flooding by high-pressure injection. The results demonstrate that the ideal surfactant system can lower the interfacial tension to 10−2 mN/m and its capacity to reduce the interfacial tension to 10−2 mN/m after different aging periods. Besides, the surfactant system possesses excellent wettability (wetting angle changed from 135° to 42°) and certain emulsifying abilities. The oil displacement experiment shows that the oil recovery rate of surfactant flooding by high pressure reaches 26%. The effect of surfactant flooding by high-pressure injection is better than that of high-pressure injection flooding.

The Role of Internal Phosphorus Loading in the Archipelago Sea Ecological Status

In eutrophic aquatic ecosystems like the Archipelago Sea in the northern Baltic, the role of the sediment as a sink and source of nutrients is especially important. Based on previous research on the Archipelago Sea, it can be concluded that the amount of stored phosphorus that can be released with time from sediments is large, and internal phosphorus recycling processes may thus play a key role in phosphorus fluxes in the coastal zone. The release of nutrients from the sediment has been suggested as an explanation for the fact that a substantial reduction in the external nutrient load does not always result in a corresponding reduction in nutrient concentrations and phytoplankton biomass in recipient waters. However, the magnitude of the actual internal phosphorus load in the Archipelago Sea has not been successfully estimated, or the estimates have been evidently too high. In this study, calculations were performed based on the measured water quality data to estimate how much phosphorus has been transported from the bottom water layer to the surface layers during the biological production season for use in algal production. In other words, the magnitude of the effective internal phosphorus load in the Archipelago Sea was determined. The calculations resulted in a summer internal net phosphorus load in the surface layer of approximately 270 tons over 5 months. The other total phosphorus load in the Archipelago Sea, which mainly (60%) originates from the catchment area, was 575 t/a. A permanent way to mitigate internal loading has been thought to be to reduce external loading. However, a decrease in internal loading occurs with an unknown delay, making it impossible to predict the recovery rate.

Complex Study of Settlements Dating from the Paleolithic to Medieval Period in the Ural Mountains on the Border of Europe and Asia

Soil, geochemical, microbiological, and archeological studies were conducted at eight settlements dating from the Paleolithic to Late Medieval and Modern Ages near the southern Trans-Urals Mountains, Russia. The forest-steppe landscapes, rivers, and abundant mineral resources have attracted people to the region since ancient times. Cultural layers (CLs) are marked by finds of ceramics fragments, animal bones, stone, and metal tools. The properties of CLs include close-to-neutral pH, being well structured, the absence of salinity, enrichment with exchangeable calcium, and anthropogenic phosphorus (0.2–0.4%). The majority of CLs start at a depth of 3–25 cm, extend to 40–60 cm, and contain 6–10% organic carbon (Corg) in the 0–20 cm layer, reflecting carbon input from modern-day processes. At the Ishkulovo site (0.6–0.8 ka BP), Corg decreases to 1.3% because the CL is below 80 cm, and in the absence of fresh organic material input, carbon has been mineralized. The proximity of sites to deposits of copper, chromium, zinc, and manganese in the Ural Mountains creates natural high-content anomalies in the region, as indicated by their abundance in soils and parent rocks. In the past, these elements were also released into CLs from metal products, ceramic fragments, and raw materials used in their manufacture. The sites are quite far (18–60 km) from the Magnitogorsk Metallurgical plant, but industrial stockpiles of S (technogenic coefficient—Ct 30–87%), and, less often, Cr, Mn, and Sr (Ct 30–40%) accumulated in surface layers. These three factors have led to the concentration of pollutants of the first (arsenic, chromium, lead, and zinc) and second (cobalt, copper, and nickel) hazard classes at CLs, often in quantities 2–5 times higher than values for parent materials and geosphere average content (“Clarke” value), and, and less often, more than the allowable content for human health. This may have influenced their health and behavioral functions. Due to the above properties, chernozems have a high buffering capacity and a strong bond with heavy metals. Therefore, no inhibition of microbes was observed. The microbial biomass of the 0–10 cm layer is high, 520–680 µg C/g, and microbes cause the emission of 1.0 C-CO2 µg/g of soil per hour. During the ancient settlements’ development, a favorable paleoclimate was noted based on the data cited. This contributed to the spread of productive paleolandscapes, ensuring the development of domestic cattle breeding and agriculture.

Direct Evidence of Microbial Sunscreen Production by Scum-Forming Cyanobacteria in the Baltic Sea.

Mycosporine-like amino acids are water-soluble secondary metabolites that protect photosynthetic microorganisms from ultraviolet radiation. Here, we present direct evidence for the production of these compounds in surface scums of cyanobacteria along the Baltic Sea coast. We collected 59 environmental samples from the southern coast of Finland during the summers of 2021 and 2022 and analysed them using high-resolution liquid chromatography-mass spectrometry. Our results revealed the presence of microbial sunscreens in nearly all surface scum samples. Mycosporine-like amino acids are synthesised through the coordinated action of four biosynthetic enzymes encoded in a compact biosynthetic pathway. Bioinformatics analysis of the mysB biosynthetic gene from a surface scum indicated that the cyanobacteria responsible for production belonged to the Anabaena/Dolichospermum/Aphanizomenon species complex. We mapped the distribution of biosynthetic enzymes onto a phylogenomic tree, utilising 120 bacterial single-copy conserved genes from 101 draft or complete genomes within the species complex. This analysis showed that 48% of identified species possess the ability to produce these compounds, with biosynthetic pathways being most common in Dolichospermum and Aphanizomenon strains. We detected the production of porphyra-334 and shinorine, two widely reported family members, in Dolichospermum strains isolated from the Gulf of Finland's surface layer. The estimated content of porphyra-334 in Dolichospermum sp. UHCC 0684 was 7.4 mg per gram dry weight. Our results suggest that bloom-forming cyanobacteria could be a potential source of these compounds for cosmetic and biotechnological applications and may play a significant role in cyanobacterial bloom formation.

Activated Graphite with Richly Oxygenated Surface from Spent Lithium-Ion Batteries for Microwave Absorption.

Designing spent graphite anodes from lithium-ion batteries (LIBs) for applications beyond regenerated batteries offers significant potential for promoting the recycling of spent LIBs. The battery-grade graphite, characterized by a highly graphitized structure, demonstrates excellent conductive loss capabilities, making it suitable for microwave absorption. During the Li-ion intercalation and deintercalation processes in battery operation, the surface layer of spent graphite (SG) becomes activated, forming oxygen-rich functional groups that enhance the polarization loss mechanism. To further control the polarization loss and achieve optimized impedance matching, reduced graphene oxide (rGO) is employed as a modifier. Herein, rGO serves as a binder, effectively combining individual SG particles. The matched Fermi levels of SG and rGO reduce the interfacial barrier, facilitating rapid electron transfer. Simultaneously, their combination forms a 3D conduction network, which not only enhances multiple scattering, reflection, and attenuation of electromagnetic waves but also provides abundant polarization centers for increased microwave absorption. As a result, the optimized SG/rGO aerogel achieves an impressive effective absorption bandwidth of 7.04GHz and accompanied by a minimum reflection loss of -51.1dB. This study broadens the scope of spent LIBs utilization and provides insights for wilder and more functional applications.

A shallow-water oxygen minimum zone in an oligotrophic Tonian basin

The Tonian Period (1000–720 Ma) bore witness to the transition from a prokaryote-dominated marine ecosystem to one characterized by the proliferation of eukaryotes. This fundamental shift has generally been attributed to evolving marine redox states. Here, we present sedimentological and geochemical analyses of the early Tonian Huainan, Feishui, and Huaibei groups in the Xuhuai basin of the North China craton. Multiple redox proxies show consistent, water depth-dependent variations across the Xuhuai basin. Excess barium contents and Ba/Al ratios further highlight spatial variations in primary productivity which ultimately regulate basinal redox structures. We propose that a shallow-water oxygen minimum zone sandwiched between the oxic/suboxic mid-depth and surface layer water masses occur in the oligotrophic Xuhuai basin, which is analogous to, but much shallower than modern oxygen minimum zones. Such marine redox architectures may benefit the maintenance of a bioavailable nitrate reservoir in the ocean, foreboding the subsequent expansion of eukaryotes.

Cs- O2 -Li as enhanced NEA surface layer with increased lifetime for GaAs photocathodes

GaAs-based photocathodes are the only viable source capable of providing spin-polarized electrons for accelerator applications. This type of photocathode requires a thin surface layer, in order to achieve negative electron affinity (NEA) for efficient photoemission. However, this layer is vulnerable to environmental and operational effects, leading to a decay of the quantum efficiency η characterized by a decay constant or lifetime τ. In order to increase τ, additional agents can be introduced during the activation procedure to improve the chemical robustness of the surface layer. This paper presents the results of recent research on Li as an enhancement agent for photocathode activation using Cs and O2, forming Cs-O2-Li as an enhanced NEA layer. Measurements yielded an increase in lifetime by a factor of up to 19±2 and an increase in extracted charge by a factor of up to 16.5±2.4, without significant reduction of η. This performance is equal to or better than that reported for other enhanced NEA layers so far. Published by the American Physical Society 2025

Research on the Influence of Magnetic Field Assistance on the Quality of an Electro-Spark Deposition Layer

Aimed at solving the problems of single control measures in the electro-spark deposition (ESD) process, difficulty controlling the micro-process using heterogeneous materials (for the electrode and matrix), and the unstable quality and reliability of repairs to the deposition layer, a method of magnetic-field-assistance electro-spark deposition (MFESD) was proposed. An MFESD device was built, and a Ni electrode was used for deposition on the surface of 45 steel under the conditions of deposition voltages of 30 V, 60 V, and 90 V, respectively. This study examined the impact of the magnetic field’s intensity and frequency on the microstructure and mechanical properties of electro-spark deposition layers. The results show that the sputtering and protrusion of the electrode material on the surface of the deposition layer gradually decrease with an increase in the magnetic field’s intensity and frequency, defects such as pores and cracks are obviously improved, and the structure is uninterrupted and compact. The surface roughness of the deposited layer decreases with an increase in the magnetic field’s intensity and frequency, and its surface roughness decreases by 44.3%. The cross-section effect of the deposited layer is improved. The thickness of the deposited layer increases with an increase in the magnetic field’s intensity and frequency; the thickness of the deposited layer increases by 13.39%, and its maximum thickness can reach 54.396 μm. At the same time, the microhardness of the deposited layer increases with an increase in the two aforementioned properties of the magnetic field, and its hardness increases by 5.32%. Using a magnetic field to control ESD can effectively control the microscopic process of deposition and obtain high-quality deposition coatings, which have important significance in the surface remanufacturing of key components of high-end equipment.

Characterization of PuO2 With Visible and UV Raman Spectroscopy: Discrimination Between the Bulk, Surface, and an Intermediate Disordered Layer

ABSTRACTRaman spectroscopy is an ideal tool in the characterization of materials including PuO2. The wavelength‐dependent absorptivity of the material defines the light penetration depth and the relative Raman scattering contribution from the bulk and the surface. The surface contribution to the total Raman scattering was investigated for PuO2 calcined at various temperatures and recorded with laser wavelengths of 355, 325, and 244 nm. These experiments provided the first glimpse of the wavelength‐dependent disappearance and emergence of new phonons and electronic bands from the PuO2 surface layers. The first indication of the wavelength transition in the Raman spectra was the loss of the 2LO2 (overtone, ~1155 cm−1) band and the weakening intensity of the Г1 → Γ5 electronic band (~2135 cm−1) with the 355‐nm excitation laser. The Γ5 electronic band was barely visible with the 244‐nm excitation. The electronic band located at ~1050 cm−1, corresponding to the Г1 → Γ4 electronic transition was observed to dramatically increase in intensity while the Г1 → Γ3 electronic band (2640 cm−1) sharpened as the UV wavelength was increased in energy from the near‐ to deep‐UV (355–325–244 nm). The FWHM of the T2g band was found to vary with calcination temperature (450°C and 900°C) with the 325‐nm laser and the 244‐nm laser. The T2g band attributes, the strong emergence of the Г1 → Γ4 electronic band, and the disappearance of the 2LO2 overtone acquired with the 244‐nm excitation for the different calcination temperatures suggest a shallow penetration depth.

Surface induced crystallization/amorphization of phase change materials

Surface-induced crystallization/amorphization of a Germanium-antimony-tellurium nanolayer is investigated using the phase field model. A Ginzburg-Landau (GL) equation introduces an external surface layer (ESL) within which the surface energy and elastic properties are adequately distributed. Next, the coupled GL and elasticity equations for the crystallization/ amorphization are solved. For the initial surface crystalline nucleus, unphysical crystallization along the ESL appears for the ESL widthΔξ⩾2nmwhile oval growth occurs forΔξ⩽1nm. The ESL results in a faster surface nucleus growth than the sharp surface model but does not affect the crystallization rate inside the bulk. Initial homogeneous conditions cause a simultaneous crystallization in the bulk and later in the ESL. The ESL effect on amorphization is studied to determine the ESL width more precisely. For both the initial amorphous nucleus and homogenous conditions, the amorphization temperature shows a reduction from the sharp surface model to the ESL model withΔξ=0.5nmand then remains almost constant for largerΔξ. Combining the above results gives0.5⩽Δξ⩽1nmas a proper range for the ESL width. The ratio of the effective ESL width to the interface width (Δsat/Δη) and the ratio of the difference between the surface energies of transforming phases to the surface energy of the initial phase (Δγ/γin) are considered crucial parameters in determining the ESL effect on the phase transformation and a linear relation asΔsat/Δη≅6.235Δγ/γinis found based on current and previous works, which can help estimate the effective ESL width for any surface-induced transformations.

A bond strength analysis of carboncor asphalt layer on road surfaces

Transport infrastructure is a critical component of socio-economic development, particularly in rapidly urbanizing Vietnam, where increasing traffic congestion poses significant challenges. Road surface quality and durability are essential factors in ensuring the efficiency and longevity of the transportation system. Carboncor Asphalt (CA) material, with its superior resistance to cracking, water damage, and harsh weather conditions, is a promising solution for road surface construction in Vietnam. However, there is a limitation of research on the mechanical behavior of carboncor asphalt in the specific climatic and environmental conditions of the country. To address this knowledge gap, this study investigates the shear behavior of a carboncor asphalt layer interfaced with both asphalt concrete and cement concrete surface layers. A comprehensive range of laboratory tests is conducted to assess the bond strength between the carboncor asphalt layer and the overlying road surfaces. Results indicate a negative correlation between temperature and bond strength for the overlay carboncor asphalt layer on both asphalt and cement concrete substrates. Notably, bond strength demonstrated a significant increase over time. The findings in this study are expected to have significant implications for road construction and maintenance using CA overlay in Vietnam. By providing a scientific foundation for material selection, design, and construction of road surfaces tailored to local conditions, this study aims to enhance investment efficiency and reduce maintenance costs

Size-dependent phase change in energy storage materials: Comparing the impact of solid-state wetting and of coherency stress.

Coherent phase transformations in interstitial solid solutions or intercalation compounds with a miscibility gap are of practical relevance for energy storage materials and specifically for metal hydride or lithium-ion compound nanoparticles. Different conclusions on the size-dependence of the transformation conditions are reached by modeling or theory focusing on the impact of either one (internal, solid-state-) critical-point wetting of the nanoparticle surface or coherency constraints from solute-saturated surface layers. We report a hybrid numerical approach, combining atomistic grand canonical Monte Carlo simulation with a continuum mechanics analysis of coherency stress and modeling simultaneously wetting and mechanical constraints. When the ratio between chemical and misfit-strain-related contributions to the solute-solute interaction energy takes values realistic for interstitial solutions-which are typical for energy storage materials-we find that the impact of solid-state wetting is weak and that of coherency stress is dominant. Specifically, mechanical interaction can act to reduce the phase transformation hysteresis at small system size, and it can make the solid more binding for solute, thereby reducing the "plateau" chemical potential at phase coexistence. We present equations for the impact of coherency stress on the size-dependence of upper consolute temperature, plateau chemical potential, and charging/discharging hysteresis.

Smuggling unnoticed: Towards a 2D view of water and dust delivery to the inner regions of protoplanetary discs

Abstract Infrared spectroscopy, e.g., with JWST, provides a glimpse into the chemical inventory of the innermost region of protoplanetary discs, where terrestrial planets eventually form. The chemical make-up of regions inside snowlines is connected to the material drifting from the outer regions, which can be modeled with dust evolution models. However, infrared observations are limited by the high dust extinction in the inner disc, and only probes the abundances of gaseous species in the disc surface layers. As a result, the bulk mass of delivered volatiles is not directly relatable to what is measured through infrared spectra. In this paper, we investigate how the delivery of dust and ice after prolonged pebble drift affects the observable reservoir of water vapor in the inner disc. We develop a 1+1D approach based on dust evolution models to determine the delivery and distribution of vapor compared to the height of the τ = 1 surface in the dust continuum. We find that the observable column density of water vapor at wavelengths probed by JWST spans many orders of magnitude over time, exhibiting different radial profiles depending on dust properties, drift rate, and local processing. In the presence of a traffic-jam effect inside the snowline, the observable vapor reservoir appears constant in time despite the ongoing delivery by pebble drift, such that water is effectively smuggled unnoticed. Differences in measured column densities then originate not only from variations in bulk vapor content, but also from differences in the properties and distribution of dust particles.