Gradients In Properties Research Articles

Analysis of Acid Diffusion Effects on Physical Properties of Polymer Composites: A Combined Study of Mechanical and Electrical Characterization

In this study, we examined the impact of carbon nanotube (CNT) concentration on the mechanical properties of epoxy/CNT composites under acid exposure. Samples with varying CNT concentrations (0% to 5%) were fabricated and characterized using dynamic mechanical analysis (DMA) and nanoindentation. Beyond the percolation threshold, the composites experienced decreased bulk mechanical properties due to CNT agglomeration. Acid exposure for one week and one month revealed a gradient of properties from the sample’s skin to its core. Overall, the composites exhibited modified physical properties, with degradation influenced by the CNT concentration. Higher concentrations acted as barriers but also created pathways for acid diffusion through pores surrounding CNT agglomerates. The agreement between nanoindentation and vector network analyzer (VNA) measurements further supported our findings. This convergence of mechanical and electromagnetic characterization techniques holds promise for wireless structural health monitoring (SHM) applications. Our study enhances the understanding of epoxy/CNT composites for SHM applications. The relationship between CNT concentration, acid exposure, and mechanical properties guides material selection and the development of real-time damage-detection techniques. Integrating multiple measurement techniques, as demonstrated by the agreement between nanoindentation and VNA data, provides a comprehensive understanding of structural behavior, improving SHM practices.

Niobium Silicide Diffusion Coatings: The Impact of Cu and of Ti on the Microstructure and High-Temperature Behavior

Abstract Silicide diffusion coatings on niobium offer attractive properties for applications at temperatures above 1,000°C because of the ability to form a protective oxide, silicon dioxide. The combination of a double layer of silicides, NbSi2 and Nb5Si3, provides a gradient of properties to the coating, mitigating the formation and propagation of cracks that otherwise allow oxygen to interact with the substrate. However, a temperature above 1,200°C is required to process double-layer silicide coatings, increasing the challenge of controlling the process and incrementing the cost of the process. The need to enhance silicide coatings without compromising their competitiveness motivates the study of the individual effects of copper and of titanium. This study processed silicide coatings by double pack cementation adding copper or titanium, respectively, to the pack mixture. Three pack mixture compositions were used: with 15 % wt. silicon, with 15 % wt. silicon + 7 % wt. copper, and 15 % wt. silicon + 7 % wt. titanium. Processing was carried out at 1,000°C for 6 hours. The coatings processed with silicon resulted on a single NbSi2 layer, but the pack mixture containing silicon and copper led to thick double-layer coatings of NbSi2 and a continuous layer of Nb5Si3, in spite of the low processing temperature. In contrast, the pack mixture containing silicon and titanium led to thinner coatings composed of a layer of NbSi2 and the discontinuous presence of Nb5Si3. Results suggest that copper and titanium impact the gaseous diffusion during processing and also the vacancy concentration in the ordered structure of NbSi2. Exposure to temperature reveals a change on the oxidation mechanisms after processing with titanium and a more significant mass gain of coatings processed with copper.

A new Rothamsted long-term field experiment for the twenty-first century: principles and practice

Agriculture faces potentially competing societal demands to produce food, fiber and fuel while reducing negative environmental impacts and delivering regulating, supporting and cultural ecosystem services. This necessitates a new generation of long-term agricultural field experiments designed to study the behavior of contrasting cropping systems in terms of multiple outcomes. We document the principles and practices of a new long-term experiment of this type at Rothamsted, established at two contrasting sites in 2017 and 2018, and report initial yield data at the crop and system level. The objective of the Large-Scale Rotation Experiment was to establish gradients of system properties and outcomes to improve our fundamental understanding of UK cropping systems. It is composed of four management factors—phased rotations, cultivation (conventional vs reduced tillage), nutrition (additional organic amendment vs standard mineral fertilization) and crop protection (conventional vs smart crop protection). These factors were combined in a balanced design resulting in 24 emergent cropping systems at each site and can be analyzed at the level of the system or component management factors. We observed interactions between management factors and with the environment on crop yields, justifying the systems level, multi-site approach. Reduced tillage resulted in lower wheat yields but the effect varied with rotation, previous-crop and site. Organic amendments significantly increased spring barley yield by 8% on average though the effect again varied with site. The plowed cropping systems tended to produce higher caloric yield overall than systems under reduced tillage. Additional response variables are being monitored to study synergies and trade-offs with outcomes other than yield at the cropping system level. The experiment has been established as a long-term resource for inter-disciplinary research. By documenting the design process, we aim to facilitate the adoption of similar approaches to system-scale agricultural experimentation to inform the transition to more sustainable cropping systems.

Variation in enamel mechanical properties throughout the crown in catarrhine primates

Enamel mechanical properties vary across molar crowns, but the relationship among mechanical properties, tooth function, and phylogeny are not well understood. Fifteen primate lower molars representing fourteen taxa (catarrhine, n = 13; platyrrhine, n = 1) were sectioned in the lingual–buccal plane through the mesial cusps. Gradients of enamel mechanical properties, specifically hardness and elastic modulus, were quantified using nanoindentation from inner (near the enamel-dentine junction), through middle, to outer enamel (near the outer enamel surface) at five positions (buccal lateral, buccal cuspal, occlusal middle, lingual cuspal, lingual lateral). Cuspal positions had higher mechanical property values than lateral positions. Middle enamel had higher mean hardness and elastic modulus values than inner and outer locations in all five crown positions. Functionally, the thicker-enameled buccal cusps of lower molars did not show evidence of increased resistance to failure; instead, lingual cusps—which show higher rates of fracture—had higher average mechanical property values, with no significant differences observed between sides. Preliminary phylogenetic results suggest there is relatively little phylogenetic signal in gradients of mechanical properties through the enamel or across the crown. There appears to be common mechanical property patterns across molar crowns in Catarrhini and potentially among primates more broadly. These results may allow more precise interpretations of dental biomechanics and processes resulting in mechanical failure of enamel in primates, such as wear and fracture.

On the imperfect interface of a functionally graded thermoelectric layered structure

This paper investigates the frictionless contact problem of a functionally graded thermoelectric (FGTE) layered half-plane under the action of a rigid flat punch. The punch is an electrical and thermal conductor. The electro-thermo-elastic properties of the FGTE materials vary exponentially with thickness. Especially, the imperfect interface conditions are taken into account. The problem is reduced to a pair of Cauchy singular integral equations using the Fourier integral transform technique, which are numerically solved to yield the surface normal electric current density, the surface normal energy flux, and the surface normal contact pressure. The asymptotic analysis of the kernel function is supplied. The intensity factors are provided to characterize the singularity at the punch ends. The contact behavior of the FGTE coating-TE substrate systems is significantly influenced by the imperfect interface condition and the material property gradient according to numerical results. The design of thermoelectric coating structures may benefit from the theoretical research done here.

Formation of mechanical property gradient along the sheet thickness due to the patterned Fe/Al IMC layers in the interface in dissimilar FSW of HSLA steel to AA 5083

HSLA steel is welded to AA 5083 by FSW technique in butt configuration and investigated for localized mechanical properties across the sheet thickness in the proximity of the interface. The quality of the weld joint was examined by macro-scale analysis, while APT data confirmed the atomic mixing status of the joint interface. The localized mechanical properties were assessed by a nanoindentation study along the interface. The variation in hardness and Young's modulus along the sheet thickness is reported. The hardness of the interface from crown to crest across thickness of the weld joint varies from ~2.7 to 5.8 GPa while Young's modulus of the region fluctuates between ~178 to 222 GPa and revealed a clear gradient over sheet thickness. The corresponding interface structure was examined by XRD2, EBSD and TEM study. The observed results collectively exhibited the distinct segregation of Fe4Al13, Fe2Al9, Fe2Al5 and Fe3Al IMC layers over the weld crown to crest (sheet thickness) with different combinations of stoichiometric variety and their quantitative presence which seems to be accountable for the noted property gradient. Overall, the nanoindentation data along with the associated microstructure analysis results of the FSW interface for the stated pair of alloys are discussed in the paper in the context of deleterious IMC layers and localized mechanical properties along the weld crown to crest.

Synthesis of functionally graded aluminium metal matrix composites - a mini review

Functionally graded materials (FGMs) are materials with property gradients along a particular dimension. These are novel and advanced materials that are becoming excellent replacements for composites. Among the FGMs, functionally graded Aluminum metal matrix composites (FG AMMCs) are receiving tremendous attention as they possess versatile properties compared to their counterparts. Out of various synthesizing techniques, the Powder metallurgy (PM) route is the cheapest and easier method of fabricating functionally graded composites (FGCs). This review provides information about the Functionally graded Aluminium metal matrix composites and their synthesis through the PM route. The review analyses important properties including density, hardness, tensile and compressive strength. A study of the microstructure through Scanning Electron Microscopy (SEM) of the synthesized FGMs is presented. The PM route could be conveniently exploited for large-scale production of FG AMMCs. There is scope for the characterization of FG AMMCs reinforced with B4C, TiO2, TiB2, TiC, CNT, and Few layered Graphene (FLG) as only a few studies are reported in the literature. The variation in mechanical and tribological properties of the FGMs could be investigated by varying the processing parameters of the ball milling, compacting, and sintering conditions.

Sound absorption behaviors of composite functionally graded acoustic structure under hydrostatic pressure

In order to overcome the drawback that the sound absorption band of traditional cavity resonance acoustic structure is narrow, the functionally graded acoustic structure (FGAS) is designed in this paper according to the characteristics of functionally graded materials (FGMs), and considering the nonlinear term of the structural strain, the graded finite element method (G-FEM) is employed to establish the acoustic calculation model for FGAS under hydrostatic pressure. The correctness of the established acoustic calculation model is verified. Three types of composites functionally graded acoustic structures (CFGAS) are designed based on geometric gradient and material property gradient. The underwater sound performance of CFGAS is investigated, and the effects of hydrostatic pressure on the sound absorption performance of CFGAS are also studied. Numerical results indicate that, the convergence and accuracy of the underwater acoustic calculation model based on the G-FEM are superior than that based on the traditional FEM. In addition, the CFGAS can improve the sound absorption performance of traditional cavity acoustic structure in the middle and high frequency bands, and its acoustic performance is insensitive to pressure, which makes FGMs have potential applications in deep water environment.

Geochemical controls on the distribution of total mercury and methylmercury in sediments and porewater from the Yangtze River Estuary to the East China Sea

A comprehensive investigation was conducted to explore the distributions of total mercury (THg) and methylmercury (MeHg) in sediments and porewater along a typical transect from the Yangtze River Estuary (YRE) to the East China Sea (ECS) open shelf. THg concentrations in the surface sediments exhibited large variations across sites, higher in the estuary mixing region, especially within the turbidity maximum zone (TMZ). The spatial and vertical distributions (0–20 cm) of THg in sediments were highly controlled by sediment grain size and total organic carbon (TOC), due to the strong binding between Hg and fine-grained sediments that enriched with organic matter. In contrast, MeHg concentrations in surface sediments were higher in the estuary mixing region and the ECS open shelf than in the river channel, with remarkably higher MeHg/THg ratios in sediments and porewater at the open shelf sites, identified as the regional hotspots of the net in situ MeHg production. Considering the large gradients of physiochemical properties of sediments, porewater and the overlying water, the results of this study suggested that the higher net Hg methylation potential in the open shelf region was largely attributed to the lower acid volatile sulfide, lower TOC and higher salinity, which facilitated the partitioning of inorganic Hg into porewater that highly bioavailable for Hg-methylation bacteria. Moreover, the estimated diffusive fluxes of MeHg at the sediment-water interface were positive at all the tested sites, and pronouncedly higher within the TMZ (driven by the higher THg loading and higher porosity) that requires special attention.

Product durability management using surface engineering technologies

The problem of managing the durability of products due to the creation of regions in materials with a given temporal and spatial non-locality is considered. A mathematical model of softening of materials under the action of external loads is proposed, allowing to take into account the special role in the formation of damaged places of exit of grain boundaries and their triple junctions on the outer surfaces of parts, as well as their interaction with stress concentrators formed after mechanical processing.
 The developed model representations are used to ensure the operational uniformity of structural elements with concentrators under stress by methods of surface engineering, in particular, when determining the role of changes in the quantitative parameters of the microstructure on the wear resistance of the surface layers of rolling stock parts of railway transport containing stressed concentrators. The optimal depth of the plasma hardening of the subsurface layers of the rims of wheel pairs of locomotives has been established, depending on the size, placement and geometric characteristics of the tension concentrators. It is shown that taking into account the dynamics of structural changes during the degradation of materials in the conditions of operation according to the proposed model ratios allows to achieve the specified life cycle of parts at minimal costs.
 Increasing the durability of products is achieved by optimizing technological modes of surface engineering, which ensure the formation of structures with a smaller gradient of properties.

Multimaterial and multiscale scaffold for engineering enthesis organ.

Tendon and ligament injuries are relevant clinical problems in modern society, and the current medical approaches do not guarantee complete recovery of the physiological functionalities. Moreover, they present a non-negligible failure rate after surgery. Failures often occur at the enthesis, which is the area of tendons and ligaments insertion to bones. This area is highly anisotropic and composed of four distinct zones: tendon or ligament, non-mineralized fibrocartilage, mineralized fibrocartilage, and bone. The organization of these regions provides a gradient in mechanical properties, biochemical composition, cellular phenotype, and extracellular matrix organization. Tissue engineering represents an alternative to traditional medical approaches. This work presents a novel biofabrication approach for engineering the enthesis. Gradient-based scaffolds were fabricated by exploiting the combination of electrospinning and three-dimensional (3D) bioprinting technologies. Studies were conducted to evaluate scaffold biocompatibility by seeding bone marrow-derived mesenchymal stem cells (BM-MSCs). Then, the scaffold's ability to promote cellular adhesion, growth, proliferation, and differentiation in both tenogenic and osteogenic phenotypes was evaluated. Fabricated scaffolds were also morphologically and mechanically characterized, showing optimal properties comparable to literature data. The versatility and potentiality of this novel biofabrication approach were demonstrated by fabricating clinical-size 3D enthesis scaffolds. The mechanical characterization highlighted their behavior during a tensile test was comparable to tendons and ligaments in vivo.

An advanced towed CTD chain for physical-biological high resolution in situ upper ocean measurements

Submesoscale eddies, fronts, and filaments are ubiquitous in the upper ocean and play an important role in biogeochemical and mixing processes as well as in the energy budget. To capture the high spatial variability of submesoscale processes, it is desirable to simultaneously resolve the vertical and horizontal gradients of hydrographic properties on scales of 10 m to 10 km. We present a revised towed CTD chain, for rapid quasi-synoptic in situ measurements of submesoscale oceanographic features, that is lighter, more robust and scientifically more useful than previous towed CTD chains. This new instrument provides a horizontal resolution of O(1 m) and can be towed at speeds of up to 5 ms-1 for measurements of the upper 100 m of the water column while providing a reasonable vertical resolution of O(1 m – 10 m). Individual CTD probes are equipped with temperature, conductivity, pressure and either rapid response dissolved oxygen or fluorescence sensors at multiple depths, enabling both hydrographic and biogeochemical studies at high resolution. A flexible probe hardware allows either real-time data collection or internal data logging for offline post-processing. Finally, we outline the necessary post-processing steps and provide data examples. With the presented data examples we show and conclude that the advanced towed CTD chain is a flexible and lightweight take on the towed CTD chain concept. It can easily be adapted to scientific needs and provides high quality very high resolution oceanographic data.

Suspension feeding in Copepoda (Crustacea) - a numerical model of setae acting in concert.

Suspension feeding via setae collecting particles is common within Crustacea. Even though the mechanisms behind it and the structures themselves have been studied for decades, the interplay between the different setae types and the parameters contributing to their particle collecting capacities remain partly enigmatic. Here, we provide a numerical modeling approach to understand the relationship among the mechanical property gradients, the mechanical behavior and the adhesion of setae, and the feeding efficiency of the system. In this context, we set-up a simple dynamic numerical model that takes all of these parameters into account and describes the interaction with food particles and their delivery into the mouth opening. By altering the parameters, it was unraveled that the system performs best when the long and short setae have different mechanical properties and different degrees of adhesion since the long setae generate the feeding current and the short ones establish the contact with the particle. This protocol can be applied to any system in the future as the parameters (i.e., properties and arrangement of particles and setae) can be easily altered. This will shed light on the biomechanical adaptations of these structures to suspension feeding and provide inspiration for biomimetics in the field of filtration technologies.

Extinction towards the cluster R136 in the Large Magellanic Cloud

Context. The cluster R136 in the giant star-forming region 30 Doradus in the Large Magellanic Cloud (LMC) offers a unique opportunity to resolve a stellar population in a starburst-like environment. Knowledge of the extinction towards this region is key for the accurate determination of stellar masses, and for the correct interpretation of observations of distant, unresolved starburst galaxies. Aims. Our aims are to construct an extinction law towards R136, and to measure the extinction towards individual sources inside the cluster. This will allow us to map the spatial distribution of the dust, to learn about dust properties, and to improve mass measurements of the very massive WNh stars inside the cluster. Methods. We obtain the near-infrared to ultraviolet extinction towards 50 stars in the core of R136, employing the ‘extinction without standards’ method. To assure good fits over the full wavelength range, we combine and modify existing extinction laws. Results. We detect a strong spatial gradient in the extinction properties across the core of R136, coinciding with a gradient in density of cold gas that is part of an extension of the Stapler Nebula, a molecular cloud lying northeast of the cluster. In line with previous measurements of R136 and the 30 Doradus region, we obtain a high total-to-relative extinction (RV = 4.38 ± 0.87). However, the high values of RV are accompanied by relatively strong extinction in the ultraviolet, contrary to what is observed for Galactic sightlines. Conclusions. The relatively strong ultraviolet extinction towards R136 suggests that the properties of the dust towards R136 differ from those in the Milky Way. For RV ~ 4.4, about three times fewer ultraviolet photons can escape from the ambient dust environment relative to the canonical Galactic extinction at the same RV and AV. Therefore, if dust in the R136 star-bursting environment is characteristic for cosmologically distant star-bursting regions, the escape fraction of ultraviolet photons from such regions is overestimated by a factor of three relative to the standard Milky Way assumption for the total-to-selective extinction. Furthermore, a comparison with average curves tailored to other regions of the LMC shows that large differences in ultraviolet extinction exist within this galaxy. Further investigation is required in order to decipher whether or not there is a relation between RV and ultraviolet extinction in the LMC.

Modeling of wave propagation in polycrystalline ice with hierarchical density gradients

Polycrystalline solids are composed of many small grains of varying sizes and crystallographic orientations. An elastic wave that propagates through such a material experiences distortion and attenuation. While the influence on propagation in random configurations can be captured with conventional statistical descriptors, the role of second-order features such as the hierarchical gradient in material properties has not been explored. In this paper, we optimize a numerical strategy based on Finite Elements and Local Max-Entropy approximants to characterize the role of grain density gradients on ultrasonic attenuation. We focus on ice as a model for mesoscale ordered configurations due to its relevance to the emerging technology of cryoultrasonics. Our simulations in one- and two-dimensional settings indicate that second-order descriptors are required to predict attenuation in polycrystalline ice. Furthermore, we define a novel parameter, based on the standard deviation of the speed of sound gradient distribution, which shows a quadratic relationship with the ultrasonic attenuation. The model results can be understood as a phase diagram for the design of metamaterials with specific ultrasonic scattering properties.

Axisymmetric contact problem of piezoelectric coating-substrate system with functionally graded piezoelectric interfacial layer

In this paper, the electromechanical response of piezoelectric coating-functionally graded piezoelectric (FGP) interfacial layer–piezoelectric substrate system under the rigid spherical punch is considered. It is assumed that the piezoelectric coating and piezoelectric substrate are connected by the FGP interfacial layer which is simulated by a multi-layer model. The axisymmetric frictionless contact problem of piezoelectric coating–substrate system with FGP interfacial layer is formulated in terms of singular integral equation with the method of transfer matrix and Hankel integral transform technique. The effect of the gradient of material properties on the stress components and electric displacement components in piezoelectric coating–substrate system is gained by solving the equation numerically. The present results could serve as a useful reference for the design of piezoelectric coating–substrate system.

Visual predation risk and spatial distributions of large Arctic copepods along gradients of sea ice and bottom depth

AbstractChanges in the community size structure of Arctic copepods toward smaller and less fat individuals or species have been linked to environmental changes. The underpinning mechanisms are, however, poorly understood. We use a two‐step hurdle regression model to analyze spatially resolved, long‐term survey data of the Barents Sea mesozooplankton community along gradients of water mass properties, sea ice, and bottom depth. We test the hypothesis that reduced visual predation, and hence increased survival in dim habitats, explains the distribution of large copepods. We expect the presence and biomass of large copepods to increase with increasing bottom depth and the occurrence of seasonal ice‐cover. The patterns and drivers that emerge from our analysis support our hypothesis: in the Barents Sea large copepods were predominantly found in deep troughs that intersect the shelf south of the polar front, or at shallower depths in seasonally ice‐covered waters northeast of Svalbard. On the banks, large copepods are largely absent whereas smaller copepods appear to survive. Top‐down control provides one plausible explanation for these distributions. Large copepods survive where sea‐ice shades the water or deep habitats permit escape from visual predators through vertical migrations. However, when upwelled onto shallow banks or flushed out from below the ice they are decimated by visual foragers. Therefore, advection and topographic blockage of vertical zooplankton distributions are key mechanisms for the efficient energy transfer and productivity in subarctic and Arctic shelf seas. New prolific foraging grounds may open up for planktivores where the ice‐edge recedes under a changing climate.

The emergence of the Gulf Stream and interior western boundary as key regions to constrain the future North Atlantic carbon uptake

Abstract. In recent years, the growing number of available climate models and future scenarios has led to emergent constraints becoming a popular tool to constrain uncertain future projections. However, when emergent constraints are applied over large areas, it is unclear (i) if the well-performing models simulate the correct dynamics within the considered area, (ii) which key dynamical features the emerging constraint is stemming from, and (iii) if the observational uncertainty is low enough to allow for a considerable reduction in the projection uncertainties. We therefore propose to regionally optimize emergent relationships with the twofold goal to (a) identify key model dynamics associated with the emergent constraint and model inconsistencies around them and (b) provide key areas where a narrow observational uncertainty is crucial for constraining future projections. Here, we consider two previously established emergent constraints of the future carbon uptake in the North Atlantic (Goris et al., 2018). For the regional optimization, we use a genetic algorithm and pre-define a suite of shapes and size ranges for the desired regions. Independent of pre-defined shape and size range, the genetic algorithm persistently identifies the Gulf Stream region centred around 30∘ N as optimal as well as the region associated with broad interior southward volume transport centred around 26∘ N. Close to and within our optimal regions, observational data of volume transport are available from the RAPID array with relative low observational uncertainty. Yet, our regionally optimized emergent constraints show that additional measures of specific biogeochemical variables along the array will fundamentally improve our estimates of the future carbon uptake in the North Atlantic. Moreover, our regionally optimized emergent constraints demonstrate that models that perform well for the upper-ocean volume transport and related key biogeochemical properties do not necessarily reproduce the interior-ocean volume transport well, leading to inconsistent gradients of key biogeochemical properties. This hampers the applicability of emergent constraints over large areas and highlights the need to additionally evaluate spatial model features.

Shock impingement on a transitional hypersonic high-enthalpy boundary layer

Shock-wave boundary layer interactions are of utmost importance for both aeronautical and aerospace applications. The dynamics of high-speed compressible turbulent boundary layers becomes tightly coupled with strong gradients of thermodynamic properties, leading to an increase of thermomechanical loads. In the contextual presence of hypersonic and high-enthalpy regimes, thermochemical nonequilibrium effects must be considered as well. This work is a first step toward the fundamental understanding of this configuration.

Climate and forest properties explain wildfire impact on microbial community and nutrient mobilization in boreal soil

The boreal landscape stores an estimated 40% of the earth's carbon (C) found in terrestrial vegetation and soils, with a large portion collected in thick organic soil layers. These ground stores are subject to substantial removals due to the centurial return of wildfire, which has strong impacts on the soil microbial community and nutrient cycling, which in turn can control ecosystem recovery patterns and process rates, such as C turnover. Currently, predictive knowledge used in assessing fire impacts is largely focused on ecosystems that experience only superficial burning and few robust observations exist regarding the effect that smoldering combustion in deeper active soil layers has on post-fire soil activity. This study provided a highly replicated and regionally extensive survey of wildfire impact on microbial community structure (using fatty acid biomarkers) and nutrient cycling (using in situ ionic resin capsules) across broad gradients of climate, forest properties and fire conditions within 50 separate burn scars and 50 additional matched unburnt boreal forest soils. The results suggest a strong metabolic shift in burnt soils due to heat impact on their structure and a decoupling from aboveground processes, releasing ecosystem N limitation and increasing mobilization of N, P, K, and S as excess in conjunction with an altered, C-starved microbial community structure and reduced root uptake due to vegetation mortality. An additional observed climatic control over burnt soil properties has implications for altered boreal forest function in future climate and fire regimes deserving of further attention.