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This paper reviews observations on processes involving concentration gradients to show that (1) Concentration gradients can do external work during discharge if the system is arranged in a manner that requires it. (2) Work has to be done on the system (i.e. energy has to be added) to create a concentration gradient. (3) Concentration gradients can spontaneously discharge with no change in energy except interaction energy. These three observations are significant since, together, these observations demonstrate an apparent violation of the law of conservation of energy which is resolved by proposing that a probability field is a common element for all concentration gradients. This paper thus introduces two new concepts into thermodynamics: (1) Many spontaneous processes occur because of an increase in probability, not because of a decrease in the energy state of the system. (2) Concentration gradients coincide with a probability field and a constraint-dependent and temperature-dependent potential energy. [ABSTRACT FROM AUTHOR]

Introduction: Hemadsorption with new sorbent cartridges is an emerging extracorporeal blood purification technique. Flow distribution inside the sorbent is one of the main issues concerning the device's performance and optimal sorbent utilization. In this experiment, we aimed to investigate the efficacy of vibration during adsorption by measuring the removal of vancomycin. Methods: In this experimental study, 1,000 mL of saline with 10 g of vancomycin was circulated in a closed circuit (set flow of 250 mL/min) simulating a hemadsorption blood run using HA380 minimodule cartridge containing 75 g of wet resin. This vibration model was implemented with a damping head device installed in front of the adsorption cartridge during the experiment. The kinetics of the vancomycin were assessed by removal ratio over 120 min. Results: We found no difference between the two models. Adsorption with and without vibration did not differ significantly for partial reduction ratios, overall amount of adsorbed molecule, or adsorption kinetics. Conclusion: The current design and structure of the minimodule cartridge demonstrated no difference in small-middle solute removal. Further improvement with the addition of mechanical vibration to the device was not observed. [ABSTRACT FROM AUTHOR]

Hydrograph separation is one of many approaches used to analyse shifts in source water contributions to stream flow resulting from climate change in remote watersheds. Understanding these shifts is vital, as shifts in source water contributions to a stream can shape water management decisions. Because remote watersheds are often inaccessible and have poorly characterized contributing water sources, or end-members, it is critical to understand the implications of using different hydrograph separation techniques in these data-limited environments. To explore the uncertainty associated with different techniques, results from two hydrograph separation techniques, mass balance and principle component analysis, were compared using 3 years of aqueous geochemical data from the East River watershed located in the Elk Mountains of Central Colorado. Solute concentrations of the end-members were characterized by both a limited set of direct chemical measurements of different sources and detailed seasonal instream chemistry to examine the influences of uncertain end-member compositions in a data-limited environment. Annual volumetric end-member contributions to stream flow had relatively good agreement across separation techniques. Large variations in time were observed in the hydrograph separations, depending on the end-member type, and estimated flow contributions varied between the selected solutes. End-member concentrations characterized by stream chemistry showed several limitations including a reduced number of distinguishable end-members and differences in timing of flow contributions. Results highlight the benefits of using multiple hydrograph separation techniques by providing a ‘weight-of-evidence’ approach to environments with limited end-member concentration data.

The influence of strain rate across three orders of magnitude (1.70 × 10−5/s to 1.43 × 10−2/s) along with the effect of the plastic strain accumulation (up to 10%) on the serrated plastic flow were investigated in the nickel-chromium (Ni-Cr) solid solution alloy Nimonic 75 by performing constant-strain-rate tension testing at 600 °C. As the strain rate decreased, the critical strain for the onset of serrations transitioned from normal behavior to inverse behavior. The serrated flow was characterized as Type A+B serration at high strain rate (1.43 × 10−2/s). In the intermediate strain-rate regime (1.43 × 10−3/s and 1.45 × 10−4/s), Type B serrations were observed and followed by a transformation to Type C+B serrations. At the low strain rate (1.70 × 10−5/s), the plastic flow immediately displayed Type C serrations, which later evolved into Type C+B serrations. Regardless of the strain rate, plastic strain, or dislocation density, a critical dislocation velocity falling in the range of 1.2 × 10−6 – 2.2 × 10−6 m/s was identified to signify the onset of Type C serration, whereby the mobile dislocations break free from the solute cloud for short bursts of deformation. Finally, a novel model by solute rearrangement across dislocation cores was used to understand how the critical dislocation velocity is quantitatively determined by the rate at which solute atoms are able to hop across the glide plane as a partial dislocation core moves through the lattice.

Understanding molten salt chemistry is essential in ongoing research of the molten salt nuclear reactor (MSR). In this context, detailed understanding of the mechanisms underlying selective oxidation of metal species, such as Cr, is required to guide the design of effective corrosion mitigation strategies in molten salts. An important starting point for such mechanistic understanding is knowledge of the solvation structure and its role in controlling metal speciation. In this work, we use ab initio molecular dynamics simulations to study the short-range (on the scale of the nearest-neighbor bond lengths) and medium-range (over length scales of several neighbor spacings) structure in three different fluoride melts with and without Cr addition; namely, 2KF-NaF, 2LiF-BeF2, and 3LiF-AlF3. We find that Cr0,Cr2+,Cr3+ can each be coordinated by different numbers of F-, with the variance in coordination number decreasing as oxidation state increases, and that these coordination geometries are largely independent of solvent. The manner by which Cr changes the medium-range structure, however, is found to be solvent-dependent. While 2KF-NaF melts show short and medium range order that is highly dynamic, 2LiF-BeF2 and 3LiF-AlF3 are characterized by molecular associates that are relatively long-lived that organize into oligomer structures on larger length scales. Rather than being solvated by F- ions alone, we find that Cr can incorporate into and be solvated within this oligomer structure. Fluoroacidity, alone, may therefore prove too simple a metric for assessing the corrosivity of molten fluorides. As our work suggests, the ability of Cr to solvate must be understood in the context of the short- and medium-range structure of the solvent.

Understanding molten salt chemistry is essential in ongoing research of the molten salt nuclear reactor (MSR). In this context, detailed understanding of the mechanisms underlying selective oxidation of metal species, such as Cr, is required to guide the design of effective corrosion mitigation strategies in molten salts. An important starting point for such mechanistic understanding is knowledge of the solvation structure and its role in controlling metal speciation. In this work, we use ab initio molecular dynamics simulations to study the short-range (on the scale of the nearest-neighbor bond lengths) and medium-range (over length scales of several neighbor spacings) structure in three different fluoride melts with and without Cr addition; namely, 2KF-NaF, 2LiF-BeF2, and 3LiF-AlF3. We find that Cr0,Cr2+,Cr3+ can each be coordinated by different numbers of F-, with the variance in coordination number decreasing as oxidation state increases, and that these coordination geometries are largely independent of solvent. The manner by which Cr changes the medium-range structure, however, is found to be solvent-dependent. While 2KF-NaF melts show short and medium range order that is highly dynamic, 2LiF-BeF2 and 3LiF-AlF3 are characterized by molecular associates that are relatively long-lived that organize into oligomer structures on larger length scales. Rather than being solvated by F- ions alone, we find that Cr can incorporate into and be solvated within this oligomer structure. Fluoroacidity, alone, may therefore prove too simple a metric for assessing the corrosivity of molten fluorides. As our work suggests, the ability of Cr to solvate must be understood in the context of the short- and medium-range structure of the solvent.

The mechanical properties of 2024 aluminum alloy were studied after two different tempers. The T351 temper (solution heat treatment, stress relief, and natural aging) leads to high hardness and toughness. A thermal treatment consisting of heat-treating at 280 °C for 48 h and slow cooling in a furnace, named TT temper, was performed to increase the precipitate size and their separation while minimizing the amount of solutes in solid solution, which produced the minimum hardness for an overaged Al2024 alloy and a lower tensile flow stress than for the T351 temper. The flow stress strongly decreases and the elongation to failure strongly increases for both materials above 300 °C. Differences in strain rate at a given stress in the power law regime at all temperatures for both tempers and compared with pure aluminum are attributed to the influence of solutes in solid solutions, affecting both the glide and climb of dislocations. However, the stacking fault energy, SFE, alone does not account for the hot deformation behavior. Thus, it is the synergistic effect of various solutes that affects the entire deformation process, causing a decrease of three or four orders of magnitude in strain rate for a given stress with respect to the pure aluminum matrix values. [ABSTRACT FROM AUTHOR]

Accurate estimations of the concentrations of soluble compounds are crucial for optimizing bioprocesses involving Escherichia coli (E. coli). This study proposes a hybrid model structure that leverages off-gas analysis data and physiological parameters, including the average biomass age and specific growth rate, to estimate soluble compounds such as acetate and glutamate in fed-batch cultivations We used a hybrid recurrent neural network to establish the relationships between these parameters. To enhance the precision of the estimates, the model incorporates ensemble averaging and information gain. Ensemble averaging combines varying model inputs, leading to more robust representations of the underlying dynamics in E. coli bioprocesses. Our hybrid model estimates acetates with 1% and 8% system precision using data from the first site and the second site at GSK plc, respectively. Using the data from the second site, the precision of the approach for other solutes was as fallows: isoleucine −8%, lactate and glutamate −9%, and a 13% error for glutamine., These results, demonstrate its practical potential. [ABSTRACT FROM AUTHOR]

Summary: Distinct survival strategies can result from trade‐offs in plant function under contrasting environments. Investment in drought resistance mechanisms can enhance survivorship but result in conservative growth. We tested the hypothesis that the widespread oaks (Quercus spp.) of the Americas exhibit an interspecific trade‐off between drought resistance and growth capacity.Using experimental water treatments, we isolated adaptive trait associations among species in relation to their broad climates of origin and tested for correlated evolution between plant functional responses to water availability and habitat.Across all lineages, oaks displayed plastic drought responses – typically acclimating through osmolyte accumulation in leaves and/or employing conservative growth. Oaks from xeric climates had higher osmolytes and reduced stomatal pore area index, which allows for moderated gas exchange and limits tissue loss.Patterns suggest drought resistance strategies are convergent and under strong adaptive pressure. Leaf habit, however, mediates the growth and drought resistance strategies of oaks. Deciduous species, and evergreen species from xeric climates, have increased drought tolerance through osmoregulation, which allows for continuous, conservative growth. Evergreen mesic species show limited drought resistance but could enhance growth under well‐watered conditions. Consequently, evergreen species from mesic environments are especially vulnerable to chronic drought and climate change. [ABSTRACT FROM AUTHOR]

Forests are critical water supply regions that are increasingly threatened by natural and anthropogenic disturbance. Evaluation of runoff-generating processes within harvested and undisturbed headwater catchments provides insight into disturbance impacts on water quality and drinking water treatability. In this study, an extensive hydrologic dataset collected at the experimental Turkey Lakes Watershed (TLW) located on the Canadian Shield was used to quantify sources of stormflow in legacy clear-cut (24-years post harvesting) and forested (control) headwater catchments using an end member mixing analysis (EMMA) model. Stream water, groundwater, soil water, and throughfall water quality were evaluated during spring snowmelt, stormflow, and fall wet-up. Groundwater chemistry was similar to stream water chemistry in both catchments, suggesting that groundwater is a major contributor to stream flow. The water chemistry in small wetlands within the study catchments was comparable to stream water chemistry, suggesting that wetlands are also important contributors to stream flow. Differences in wetland position between the legacy clear-cut and control catchments appeared to have a greater influence on source contributions than legacy harvesting. Results from this study provide insight into runoff-generation processes that reflect event/seasonal flow dynamics and the impacts on water quality. [ABSTRACT FROM AUTHOR]

Self-interstitial atoms (SIAs) are the dominant self-defects at equilibrium in metals, but many questions such as their diffusion characteristics are still open, and studies of the Ti/Cr effect on the kinetics of SIAs are very scarce in vanadium alloy. In this work, we systemically investigated the migration mechanisms of mono/di-interstitials as well as the effect of alloying elements Ti/Cr on the kinetics of SIAs using first-principles calculations. The findings reveal that 〈111〉SIA exhibits three migration mechanisms, including one dimensional (1D) migration, translation-rotation and translation, corresponding energy barriers of 0.008, 0.19 and 0.44 eV. Different migration pathways are activated at high temperatures, which supports the experimental observation of 3D migration of SIAs under high temperatures. We determined the di-SIA (two parallel 〈111〉SIA) migration by both successive and simultaneous jumping paths, the lowest migration barrier is 0.009 eV via successive jumping path passing a translation state. Moreover, based on three migration mechanisms of SIA, SIA migrating to Ti region possesses the lower barrier than pure vanadium, in verse the barrier is relative high and then hinders the SIA diffusion. The alloying Ti has a pinning effect on SIAs. And we explored how SIA to form mixed V-Cr interstitial and its migration of 〈111〉V-Cr. Finally, we estimated the effect of Ti on SIA diffusivity by empirical formulas. [ABSTRACT FROM AUTHOR]

Aquaporins constitute a family of transmembrane proteins that function to transport water and other small solutes across the cell membrane. Aquaporins family members are found in diverse life forms. Aquaporins share the common structural fold consisting of six transmembrane alpha helices with a central water-transporting channel. Four such monomers assemble together to form tetramers as their biological unit. Initially, aquaporins were discovered as water-transporting channels, but several studies supported their involvement in mediating the facilitated diffusion of different solutes. The so-called water channel is able to transport a variety of substrates ranging from a neutral molecule to a charged molecule or a small molecule to a bulky molecule or even a gas molecule. This article gives an overview of a diverse range of substrates conducted by aquaporin family members. Prime focus is on human aquaporins where aquaporins show a wide tissue distribution and substrate specificity leading to various physiological functions. This review also highlights the structural mechanisms leading to the transport of water and glycerol. More research is needed to understand how one common fold enables the aquaporins to transport an array of solutes. [ABSTRACT FROM AUTHOR]

Most studies of land use effects on solute concentrations in streams have focused on smaller streams with watersheds dominated by a single land‐use type. Using land cover as a proxy for land use, the objective of this study was to determine whether the hydrologically‐driven response of solutes to land use in small streams could be scaled up to predict concentrations in larger receiving streams and rivers in the rural area of the Little Tennessee River basin. We measured concentrations of typically limiting nutrients (nitrogen, phosphorus), abundant anions (chloride, sulfate), and base cations in 17 small streams and four larger river sites. In the small streams, total solute concentration was strongly related to land cover ‐‐ highest in streams with developed watersheds, lowest in streams with forested watersheds, and streams with agricultural watersheds were in between. In general, the best predictor of solute concentrations in the small streams was forest land cover. We then predicted solute concentrations for the river sites based on the solute‐‐land cover relationships of the small streams using multiple linear regressions. Results were mixed ‐‐ some of the predicted river concentrations were close to measured values, others were greater or less than measured concentrations. In general, river concentrations did not scale with land cover‐solute relationships found in small tributaries. Measured values of nitrogen solutes in the river sites were greater than predicted, perhaps due to the presence of waste water treatment plants. We attributed other differences between measured and predicted river concentrations to the heterogeneous geochemistry of this mountainous region. The combined complexity of hydrology, geochemistry, and human land‐use of this mountainous region make it difficult to scale up from small streams to larger river basins. [ABSTRACT FROM AUTHOR]

• The coarse-grained overaged WE54 alloy was refined to 1 µm by severe FSP. • Thus, deformation mechanism at high temperature changed from solute-drag creep to GBS. • Comparison of Mg alloys showed that heavier solutes give less superplastic response. • The accommodation process for GBS is hindered by low solute diffusion rates. The coarse-grained WE54 magnesium alloy was heat treated in order to have minimum hardness minimizing the effects of precipitates and solid solution. Friction stir processing (FSP) was applied in severe conditions to obtain fine, equiaxed and highly misoriented grains, with grain sizes even less than 1 µm. The high severity of processing demonstrated to have a strong impact in the microstructure. Consequently, the processed materials exhibited excellent superplasticity at the high strain rate 10−2 s−1, and temperatures between 300 and 400 °C. The maximum tensile superplastic elongation of 756% was achieved at 400 °C thanks to the operation of grain boundary sliding mechanism (GBS). Besides the new data obtained through tensile testing, the paper deals with a transcendental question regarding the large differences in strain rate values at a given stress in the superplastic regime at maximum elongation compared to other magnesium-based alloys. With this is mind, 19 magnesium alloys from 22 different investigations were analyzed to give some light to this behavior that never was treated before. It is proposed that this behavior has to be attributed to the accommodation process, necessary for GBS to occur, which is hindered by reinforcing solutes. [ABSTRACT FROM AUTHOR]

Hot tensile tests were performed to assess the temperature and strain rate dependency of the yield strength of particle-containing aluminium wrought alloys. In this class of alloys yield strength accrues from a combination of the intrinsic matrix strength of pure Al, the strength due to second-phase particles and the strength due to alloy elements in solid solution. In Mg-containing Al alloys dynamic strain ageing (DSA) adds an extra strength contribution in a certain range of temperatures and strain rates. For each of these mechanisms a suitable constitutive model was devised; the resultant yield strength predictions were compared to the experimental results of various particle-containing Al sheet alloys. For non-heat-treatable Al alloys where the effect of sub-micron sized dispersoids is predominant, the model is capable of predicting the experimental yield strength with good accuracy, including the general decrease of yield strength with increasing temperature and a rather mild strain rate sensitivity. In Mg-containing alloys the incorporation of DSA was decisive to yield adequate model predictions, especially in an intermediate temperature range where DSA is most pronounced. It is only at very high temperatures and/or low strain rates that the presumed activation of additional rate-sensitive deformation mechanisms led to a significant softening of the Mg-bearing alloys which is not covered by the present modelling approach. [ABSTRACT FROM AUTHOR]

High‐latitude glacierized coastal catchments of the Gulf of Alaska (GoA) are undergoing rapid hydrologic changes in response to climate change and glacial recession. These catchments deliver important nutrients in the form of both inorganic and organic matter to the nearshore marine environment, yet are relatively understudied with respect to characterization of the sediment and solute generation processes and total yields. Using multiple linear regression informed by Bayesian Information Criterion analysis we empirically demonstrate how watershed characteristics affect suspended sediment and solute generation as represented by concentration‐discharge relationships. We find that watershed mean slope and relief control solute generation and that solute yields are influenced most by glacier coverage. We contribute a new flux and concentration‐discharge based conceptualization for understanding solute cycles across a hydroclimatic gradient of GoA watersheds that can be used to better understand future watershed responses to rapid hydrologic change. Plain Language Summary: The Gulf of Alaska (GoA) region is experiencing rapid changes in climate causing glaciers to recede. Streams and rivers within basins that contain glaciers deliver vital nutrients to the ocean. However, regional studies to quantify the generation and delivery of rock‐derived nutrients from watersheds to the ocean are lacking. This study uses statistical analysis to identify the mechanisms controlling the release of nutrients and to demonstrate the physical watershed characteristics that influence the flux of nutrients at the watershed scale. We find that topographic characteristics (slope and relief) control nutrient‐generating processes and that glacier coverage is an important factor controlling the total amount of nutrients exported by streams. This contribution presents a new conceptualization for understanding nutrient delivery to the GoA that can be used to understand future responses to changing climate regimes. Key Points: Catchment glacial coverage controls annual solute yields consistent with the global trend in basins with similar glacier coverageWatershed geomorphology has strong controls on concentration‐discharge relationshipsSolute yields are most significantly influenced by glacier coverage [ABSTRACT FROM AUTHOR]

We examined how climate variability affects the mobilization of material from six watersheds. We analyzed one to seven years of high‐frequency sensor data from a temperate ecosystem and a tropical rainforest. We applied a windowed analysis to correlate concentration‐discharge (C‐Q) behavior with climate anomalies, providing insight into how hydrological and biogeochemical processes change in response to climate variability. Positive precipitation anomalies homogenized the C‐Q responses for dissolved organic matter, nitrate, specific conductance and turbidity, indicating that hydrological processes dominate the C‐Q signal and watersheds act as "conveyor belts" of material. In contrast, drier and warmer conditions led to C‐Q behavior associated with variation in solute concentration, suggesting that biogeochemical processes are a primary control on solute export and their response to flow. Results indicate that climate variability can move watersheds along a continuum from transporter‐to‐transformer of biologically active solutes and responses can potentially vary by biome. Plain Language Summary: Watersheds transport and transform material as water moves through the landscape to downstream waterbodies. We evaluated how variability in precipitation and temperature affect the movement of solutes and sediment from watersheds to river networks in temperate forests and tropical rainforests by examining the relationships between concentration and flow across six watersheds. We found that during wetter than typical conditions, hydrology dominates the relationship between concentration and discharge and watersheds act as a conveyor belt of material to the stream network. During drier and warmer than typical conditions, we observed high variability in concentration of solutes relative to discharge suggesting that watershed and in‐stream biogeochemical processes are the primary control on solute export. Under these conditions, the stream and watershed acts as a transformer of material. These results indicate that variability in climate can move watersheds and river networks along a continuum from transporter‐to‐transformer of biologically active solutes. Key Points: Watersheds transition along a transporter‐transformer continuum across a range of precipitation anomalies in tropical and temperate biomesSynergistic effects of dry conditions and warming temperatures may affect the export of biologically reactive solutes in temperate systemsHigher nitrate flux occurred during negative precipitation anomalies than during the largest positive precipitation anomalies [ABSTRACT FROM AUTHOR]

Monitoring the temporal variation of solute concentrations in streams at high temporal frequency can play an important role in understanding the hydrological and biogeochemical behaviour of catchments. UV–visible spectrometry is a relatively inexpensive and easily used tool to infer those concentrations in streams at high temporal resolution. However, it is not yet clear which solutes can be modelled with such an in‐situ sensor. Here, we installed a UV–visible spectrometer probe (200–750 nm) in a high‐altitude tropical Páramo stream to record the wavelength absorbance at a 5‐min temporal resolution. For calibration, we simultaneously sampled stream water at a 4‐h frequency from February 2018 to March 2019 for subsequent laboratory analysis. Absorbance spectra and laboratory‐determined solute concentrations were used to identify the best calibration method and to determine which solute concentrations can be effectively inferred using in situ spectrometry through the evaluation of six calibration methods of different mathematical complexity. Based on the Nash–Sutcliffe efficiency (NSE) and Akaike information criterion metrics, our results suggest that multivariate methods always outperformed simpler strategies to infer solute concentrations. Eleven out of 21 studied solutes (Al, DOC, Ca, Cu, K, Mg, N, Na, Rb, Si and Sr) were successfully calibrated (NSE >0.50) and could be inferred using UV–visible spectrometry even with a reduced daily sampling frequency. It is worth noting that most calibrated solutes were correlated with wavelengths (WLs) in the low range of the spectra (i.e., UV range) and showed relatively good correlation with DOC. The latter suggests that estimation of metal concentrations could be possible in other streams with a high organic load (e.g., peat dominated catchments). In situ operation of spectrometers to monitor water quality parameters at high temporal frequency (sub‐hourly) can enhance the protection of human water supplies and aquatic ecosystems as well as providing information for assessing catchment hydrological functioning. [ABSTRACT FROM AUTHOR]

Abstract The area was mineralized, yet it is an agricultural settlement. Histories of water hardness and local migration of connate (saline) water exist across the region. This study investigated effects of these geogenic circumstances on the economy of the region and Nigeria. Geophysical and geochemical analyses were carried out for delineation of hydrological structures relevant to groundwater movement and pollution status, respectively. Results revealed silty–sandy shale sandwiched between 60 and 100 Ω-m at the fourth geoelectric layer. This layer marks depths to water table from 7.0 to 12.0 m and formed aquitard as medium of regional stance for groundwater percolation. The aquitards confined localized resistivity anomalies of ≤ 60 Ω-m and was interpreted as various aquifers. Isolated peaks of hydraulic head up to 85 m around north-western and south-eastern ends of NW–SE-trending local water divide indicated areas of water table crops where conjunctive hydrological interaction exists between surface water and groundwater resources; each flushes dissolved elements from the calcareous sediments into the water resources. Consequently, configurations of pH, total dissolved solutes (TDS), electrical conductivity (EC) and total hardness ranged as: 6.97–7.96, 20–1399 mg/l, 30–2100 μs/cm and 8–160 mg/l, respectively. Localized concentrations of calcium, sodium, bicarbonate, sulphate, chloride, iron, manganese, zinc, lead, chromium and cobalt in mg/l ranged to pollution or alert levels as follows: 38–590, 5–89, 10–126, 30–460, 6–128, 0.01–1.74, 0.1–0.41, 0.001–0.13, 0/01–1.98, 0.011–0.56 and 0.05–0.22, respectively. The water is therefore hard and hence supports encrustations of fittings for water supplies. Consequently, screens’ slot sizes were clogged, resulting in incessant boreholes failures in the region. Heavy metals are polluting from identifiable loading sources, possibly, due to the proximity of associated lodes. These pollution(s) caused the exceedance of TDS (as reflected in EC) above the saline borderline and hence the salinity and sodium hazards that hampered crop growth, mainly cereal foods. It also endangered biodiversity of adjoining downstream regions.

An important aspect of the characterisation of non-heat-treatable Al alloys is the constitution of the material in terms of its alloying elements in solid solution and, in turn, volume, size, morphology and species of second-phase particles. These constitutional characteristics, conveniently summarised as micro-chemistry, have an impact on physical and mechanical materials properties of Al semi-finished products. In the present study, the evolution of micro-chemistry in the Al–Mn alloys of the AA 3xxx series during solidification and homogenisation is analysed. Especially, we focus on the impact of additional alloy elements, including Si, Mg and Cu, on the phase selection during solidification and the changes in solute level and volume, size and type of second-phase particles during subsequent homogenisation. [ABSTRACT FROM AUTHOR]

Floodplains perform diverse functions, including attenuation of fluxes of water, solutes, and particulate material. Critical details of floodplain storage including magnitude, duration, and spatial distribution are strongly influenced by floodplain biogeochemical processes and biotic communities. Floodplain storage of diverse materials can be conceptualized in the form of a budget that quantifies inputs, outputs, and storage within the floodplain control volume. The floodplain control volume is here defined as bounded on the inner edges by the banks of the active channel(s), on the outer edges by the limit of periodic flooding and the deposition of fluvially transported sediment, on the underside by the extent of hyporheic exchange flows and the floodplain aquifer, and on the upper side by the upper elevation of living vegetation. Fluxes within the floodplain control volume can also change the location, characteristics, and residence time of material in storage. Fluxes, residence time, and quantities of material stored in floodplains can be measured directly; inferred from diverse types of remotely sensed data; or quantitatively estimated using numerical models. Human activities can modify floodplain storage by: hydrologically and/or geomorphically disconnecting channels and floodplains; altering fluxes of water and sediment to the river corridor; and obliterating floodplains through alluvial mining or urbanization. Floodplain restoration can focus on enlarging the functional floodplain, reconnecting the channel and floodplain, restoring natural regimes of water, sediment, and/or large wood, or enhancing the spatial heterogeneity of the channel and floodplain. Each form of floodplain restoration can increase floodplain storage and resilience to disturbances. Plain Language Summary: Floodplains perform diverse physical and ecological functions and these functions are highly interconnected. The chief physical function of floodplains is attenuation of fluxes of water, along with dissolved material, sediment, and organic matter transported by water. Although floodplain storage is a physical process, critical details of storage including magnitude, duration, and spatial distribution are strongly influenced by floodplain biogeochemical processes and biotic communities. Floodplain storage can be conceptualized in the form of a budget that quantifies inputs, outputs, and storage. Fluxes, residence time, and quantities of material stored in floodplains can be measured directly; inferred from diverse types of remotely sensed data; or quantitatively estimated using numerical models. Human activities can modify all of the factors influencing floodplain storage by hydrologically and/or geomorphically disconnecting channels and floodplains; by altering fluxes of water and sediment to the river corridor; and by obliterating floodplains through alluvial mining or urbanization. Floodplain restoration can focus on enlarging the functional floodplain, reconnecting the channel and floodplain, restoring natural regimes of water, sediment, and/or large wood, or enhancing the spatial heterogeneity of the channel and floodplain. Each of these forms of floodplain restoration can increase floodplain storage and resiliency to natural and human disturbances Key Points: Storage of diverse materials constitutes a vital floodplain functionCharacteristics of floodplain storage reflect floodplain size, connectivity, and spatial heterogeneityHuman activities can increase or decrease floodplain storage, but human alteration of floodplain storage is common [ABSTRACT FROM AUTHOR]