Hydrous State Research Articles

Viscoelastic Response in Hydrous Polymers: The Role of Hydrogen Bonds and Microstructure.

Water responsive polymers represent a remarkable group of soft materials, acting as a laboratory for diverse water responsive physical phenomena and cutting-edge biology-electronics interfaces. We report on peculiarly distinctive viscoelastic behaviors of the biobased water responsive polymer cellulose 10-undecenoyl ester, while biobased regenerated cellulose displays stronger hydroplastic behaviors. We discovered a novel hydrous deformation mechanism involving the stretching of hydrogen bonds mediated by hydroxyl groups and water molecules, serving as a crucial factor in accommodating deformations. In parallel, the microstructure of cellulose 10-undecenoyl ester with unique coexisting nanoparticles and a continuous phase of entangled chains is mechanically resilient in the anhydrous state but enhances structural stiffness in the hydrous state. This variation arises from a different hydration level within the hydrous microstructure. Such a fundamental discovery offers valuable insights into the connection between the microscopic physical properties that can be influenced by water and the corresponding viscoelastic responses, extending its applicability to a wide range of hygroscopic materials.

Meso- to Neoarchean geodynamic transition of the North China Craton indicated by H2O-in-zircon for TTG suite

Tonalite-trondhjemite-granodiorite (TTG) suites constitute nuclei of many ancient cratons, holding a key to reveal how continental crust formed and evolved in the early Earth. Archean to Paleo-Proterozoic TTG rocks are widely reported in the North China Craton (NCC), and have been widely used to infer continental crust growth and reworking. Previous whole-rock geochemical studies on these rocks had led to the proposal of Neoarchean subduction onset and the establishment of the Meso- to Neoarchean thermal state for this craton. However, whole-rock geochemical compositions can be modified by post-magmatic alternation or metamorphism. The content of water in zircon (a resistant mineral) have the potential to characterize the hydrous state of magma. Here, in order to track the NCC geodynamic evolvement from the Mesoarchean to the Paleoproterozoic, we measured the H2O-in-zircon content with a newly developed low background secondary ion mass spectrometer (SIMS) method for a Neoarchean-Paleoproterozoic (2.8–2.1 Ga) TTG suite in the central NCC. Our results show an abrupt zircon water content rise at the Paleoproterozoic-Neoarchean boundary (∼2.5 Ga), from ∼100 ppm for ∼2.8 Ga TTG rocks to > 1000 ppm for ∼2.5 and ∼2.1 Ga TTG rocks. In addition, zircon elemental ratios (e.g., U/Yb and Nb/Yb) also show a markable magmatic provenance change at the same time from MOR (mid-ocean-ridge)-type to arc-type. We link these changes to the initiation of plate subduction in the North China Craton.

Cretaceous crustal melting records of tectonic transition from subduction to slab rollback of the Paleo-Pacific Plate in SE China

The Mesozoic geology of SE China has been widely considered to relate to subduction of the Paleo-Pacific Plate beneath the Eurasia, accompanied with extensive felsic magmatism. However, the relationship between the origin of the voluminous crust-derived magmatism and the Paleo-Pacific slab subduction remains unclear. Here we present petrology, zircon U-Pb-Hf isotope data, and whole-rock geochemical and isotopic compositions of two episodes of Cretaceous silicic volcanic rocks (~114–113 Ma for Group 1 and ~ 100–93 Ma for Group 2) from southeastern Zhejiang Province in SE China, to provide new constraints on the geodynamic transition of the Paleo-Pacific slab subduction. Both volcanic groups show similarly unradiogenic whole-rock εNd(t) and zircon εHf(t) values (εNd(t) = −8.6 to −6.4 and εHf(t) = −8.5 to −0.7 for Group 1, and εNd(t) = −7.1 to −6.1 and εHf(t) = −7.8 to −2.2 for Group 2). The limited emplacement of coeval mafic magmas and absence of mafic microgranular enclave and intermediate lavas suggest an insignificant role of mantle-derived melt either as a parental magma for differentiation or a mafic component during magma mixing. Instead, the low MgO and high concentrations of SiO2 and incompatible elements and the evolved Nd and Hf isotopic compositions indicate derivation of these two groups of silicic magmas from similar hybrid crustal sources containing the metasedimentary rocks of Cathaysia basement and the newly accreted arc crust. Group 1 rocks contain a higher proportion of hydrous minerals (e.g., biotite) and Sr/Y and La/YbCN ratios but lower zircon saturation temperature than Group 2. Such variations in mineral and geochemical compositions could be mainly attributed to the change of melting conditions from a relatively deeper, colder and water-fluxed crust to a shallower, hotter and less hydrous state. By combining our new results and previous studies of the late Mesozoic volcanic rocks in SE China, we propose that a geodynamic transition from subduction to slab rollback of the Paleo-Pacific Plate was responsible for such P-T-H2O variations of the crustal source.

Graphene induced crystallinity and hydrous state variations of ruthenium oxide electrodes for superior energy storage performance

This work adopts a thermal decomposition (TD) method for fabricating electrochemically exfoliated graphene (ECG)-modified ruthenium oxide thin film as the electrode material for high-performance supercapacitors. The TD technique consists of three consecutive thermal annealing steps for layer-by-layer coating of RuO2/ECG on the Ti substrate. We have demonstrated that the ECG content is the key factor influencing the electrochemical performance of the composite electrodes. The introduction of an appropriate amount of ECG within the composites facilitates the utilization of RuO2 and enables high capacitance, low charge transfer resistance, high rate capability, and superior durability. An optimal ECG content (5 wt.%) mixed with deposited RuO2 forms a three-dimensional conductive framework, capable of offering a synergistic effect for enhanced charge transfer as well as fast ionic diffusion. The specific capacitance of the RuO2/ECG electrode reaches as high as 407 F g−1 while maintaining the high capacitance (> 97%) during prolonged cycling (2000 cycles). The Ragone plot confirms that the RuO2/ECG capacitor enables a high energy density of 10.2 Wh kg−1 while delivering a remarkable power density of 9.2 kW kg−1. The RuO2/ECG composite developed in this work paves the way for designing robust electrode materials for high-performance supercapacitors.

Dynamics in the Uppermost Lower Mantle: Insights into the Deep Mantle Water Cycle Based on the Numerical Modeling of Subducted Slabs and Global-Scale Mantle Dynamics

In this review, we address the current status of numerical modeling of the mantle transition zone and uppermost lower mantle, focusing on the hydration mechanism in these areas. The main points are as follows: ( a) Slab stagnation and penetration may play significant roles in transporting the water in the whole mantle, and ( b) a huge amount of water could be absorbed into the deep mantle to preserve the surface seawater over the geologic timescale. However, for further understanding of water circulation in the deep planetary interior, more mineral physics investigations are required to reveal the mechanism of water absorption in the lower mantle and thermochemical interaction across the core–mantle boundary region, which can provide information on material properties to the geodynamics community. Moreover, future investigations should focus on determining the amount of water in the early planetary interior, as suggested by the planetary formation theory of rocky planets. Moreover, the supplying mechanism of water during planetary formation and its evolution caused by plate tectonics are still essential issues because, in geodynamics modeling, a huge amount of water seems to be required to preserve the surface seawater in the present day and to not be dependent on an initial amount of water in Earth's system. ▪ Slab stagnation and penetration of the hydrous lithosphere are essential for understanding the global-scale material circulation. ▪ Thermal feedback caused by water-dependent viscosity is a main driving mechanism of water absorption in the mantle transition zone and uppermost lower mantle. ▪ The hydrous state in the early rocky planets remains to be determined from cosmo- and geochemistry and planetary formation theory. ▪ Volatile cycles in the deep planetary interior may affect the evolution of the surface environment.

The role of steam in selective oxidation of methacrolein over H3PMo12O40

Role of steam in selective oxidation of methacrolein with molecular oxygen over H3PMo12O40 catalyst was investigated. Addition of steam to feed gas significantly enhanced both catalytic activity and selectivity to methacrylic acid, which were fivefold and twice increases, respectively, under the optimal steam pressure (PH2O = 0.13 atm). Kinetic analysis demonstrated that the addition of steam caused 200-fold increase in the pre-exponential factor for the formation of methacrylic acid, leading to the significant increase in the activity. The steam in the feed gas varied hydrous state of H3PMo12O40 under the reaction conditions, while did not alter redox property, molecular and crystalline structures, and surface area of the catalyst. In the presence of steam at 573 K, three H2O per one H3PMo12O40 were absorbed and hydrated protons like [H3O]+ were formed in the bulk of H3PMo12O40. Methacrolein was adsorbed on the surface of the hydrous catalyst, but not on anhydrous one at all. Based on the results, it was concluded that activation of methacrolein readily occurred on the catalyst in the presence of steam, leading to the significant increase in the pre–exponential factor. Quantum chemical calculation supported the smooth activation of methacrolein by the reaction with [H3O]+ without any transition state.

Copolymers enhance selective bacterial community colonization for potential root zone applications

Managing the impact of anthropogenic and climate induced stress on plant growth remains a challenge. Here we show that polymeric hydrogels, which maintain their hydrous state, can be designed to exploit functional interactions with soil microorganisms. This microbial enhancement may mitigate biotic and abiotic stresses limiting productivity. The presence of mannan chains within synthetic polyacrylic acid (PAA) enhanced the dynamics and selectivity of bacterial ingress in model microbial systems and soil microcosms. Pseudomonas fluorescens exhibiting high mannan binding adhesins showed higher ingress and localised microcolonies throughout the polymeric network. In contrast, ingress of Bacillus subtilis, lacking adhesins, was unaltered by mannan showing motility comparable to bulk liquids. Incubation within microcosms of an agricultural soil yielded hydrogel populations significantly increased from the corresponding soil. Bacterial diversity was markedly higher in mannan containing hydrogels compared to both control polymer and soil, indicating enhanced selectivity towards microbial families that contain plant beneficial species. Here we propose functional polymers applied to the potential root zone which can positively influence rhizobacteria colonization and potentially plant growth as a new approach to stress tolerance.

Hydrous state of the subducting Philippine Sea plate inferred from receiver function image using onshore and offshore data

AbstractExploring the hydrous state of subducting oceanic crust is intriguing because it is considered to affect the strength of megathrust faults that cause various types of earthquakes; however, its state beneath offshore regions remains unclear. In this study, we investigated fluid contents along the subducting Philippine Sea plate around the Kii Peninsula by receiver function (RF) analysis using data from both on‐land stations and ocean bottom seismometers (OBSs). The vertical component of OBS records contains dominant water reverberations, and thus, conventional methods fail to estimate RFs correctly. We therefore developed a method to calculate RFs that removes such reverberations. The RFs calculated by our method showed considerable improvement for later phase identification, compared with those obtained using a conventional method. Resultant RF amplitudes suggest the existence of low‐velocity zones directly beneath the plate interface of both onshore and offshore regions. We interpreted this as evidence of hydrous oceanic crust, which extends from 5 km to 35 km depth to the plate interface. Reduction of RF amplitudes beneath the Kii Peninsula suggests that dehydration of the oceanic crust increases the seismic velocity, and the accompanying densification makes the plate interface permeable. This permeable plate interface may characterize the location of non‐volcanic tremors. This contrasts with long‐term slow slip events because it is believed that they occur along the sealed plate interface. Comparison between the plate geometry and local earthquakes reveals the paucity of earthquakes in the oceanic crust below a certain depth, which provides further insight into the dehydration process in the oceanic crust.

Uptake of cesium and strontium ions by artificially altered phlogopite.

Potassium (K(+)) phlogopite was transformed to a vermiculite-like mineral through a topotactic reaction under acidic conditions (pH 2) followed by hydrothermal treatment with Na(+), Mg(2+), Ca(2+), and Al(3+) cations. The resulting Na(+)-, Mg(2+)-, Ca(2+)-, and Al(3+)-altered phlogopites (Phl) denoted as Na-Phl, Mg-Phl, Ca-Phl, and Al-Phl, respectively. Na-Phl, Mg-Phl, and Ca-Phl all exhibited the same high adsorption capacity as natural vermiculite and the absorption of Cs(+) and Sr(2+) ions on these materials followed the Langmuir model. High-angle annular dark-field scanning transmission electron microscopy showed that Cs(+) ions in the Mg-Phl layers were intercalated deep within the crystal structure, along specific interlayer regions. These adsorbed anhydrous Cs(+) ions were firmly fixed at the centers of hexagonal rings positioned simultaneously in the upper and lower tetrahedral silicate sheets, whereas Sr(2+) ions adsorb into the interlayer in the hydrous state. Al-Phl formed a hydroxyl-interlayered vermiculite and demonstrated significant selectivity for Cs(+) at very low concentrations of the isotope. Consequently, the artificially altered phlogopites prepared in this study showed controllable and versatile adsorption capabilities making them significantly more suitable than natural vermiculite for Cs and Sr decontamination.

Electrical conductivity of continental lithospheric mantle from integrated geophysical and petrological modeling: Application to the Kaapvaal Craton and Rehoboth Terrane, southern Africa

[1] The electrical conductivity of mantle minerals is highly sensitive to parameters that characterize the structure and state of the lithosphere and sublithospheric mantle, and mapping its lateral and vertical variations gives insights into formation and deformation processes. We review state-of-the-art conductivity models based on laboratory studies for the most relevant upper mantle minerals and define a bulk conductivity model for the upper mantle that accounts for temperature, pressure, and compositional variations. The bulk electrical conductivity model has been integrated into the software package LitMod, which allows for petrological and geophysical modeling of the lithosphere and sublithospheric upper mantle within an internally consistent thermodynamic-geophysical framework. We apply our methodology to model the upper mantle thermal structure and hydrous state of the western block of the Archean Kaapvaal Craton and the Proterozoic Rehoboth Terrane, in southern Africa, integrating different geophysical and petrological observables: namely, elevation, surface heat flow, and magnetotelluric and xenolith data. We find that to fit the measured magnetotelluric responses in both the Kaapvaal and Rehoboth terranes, the uppermost depleted part of the lithosphere has to be wetter than the lowermost melt-metasomatized and refertilized lithospheric mantle. We estimate present-day thermal lithosphere-asthenosphere boundary (LAB) depths of 230–260 and 150 ± 10 km for the western block of the Kaapvaal and Rehoboth terranes, respectively. For the Kaapvaal, the depth of the present-day thermal LAB differs significantly from the chemical LAB, as defined by the base of a depleted mantle, which might represent an upper level of melt percolation and accumulation within the lower lithosphere.

Surface deformation of an intraplate area from GPS time series

The aim of this study is to identify the processes that lead to the ground surface deformation above the fractured crystalline aquifer of Ploemeur (French Brittany). We conducted a four-year continuous GPS data survey in order to extract the hydrogeological contribution due to the variations of the hydraulic head of the confined aquifer. The GPS configuration used in this study, with a differential setup, short baselines and adapted processing parameters, may have removed tide effects, ocean tide loading and tectonics trends. We checked in particular the case of ocean tide loading because of its important contribution in Brittany. Time series calculated with GAMIT software indicate a seasonal deformation on both vertical direction (up to 16 mm of displacement) and horizontal plane (from 3 to 12 mm of displacement) that provide a 3D motion. This sub-annual deformation is induced by variations of the hydraulic head of the aquifer and depends on its 3D hydromechanical properties. However, an offset between ground uplift and piezometric rise could not be explained by pressure variations into the deep aquifer and was linked to the variations of the hydrous state of the ground. This GPS study highlights that the hydrogeological and hydrological processes act significantly on ground motion and should be integrated in any Earth deformation survey.

Physicochemical factors that affect the pseudocapacitance and cyclic stability of Mn oxide electrodes

Manganese (Mn) oxide was prepared by anodizing metallic Mn film that was electrodeposited in n-butylmethylpyrrolidinium bis(trifluoromethylsulfony)imide (BMP–NTf 2) ionic liquid. Different anodization courses, namely potentiostatic and cyclic voltammetric methods, led to variations in physical and chemical characteristics of the Mn oxides, and therefore in their pseudocapacitive performance. Evolution of the microstructure, residual weight, and chemical state of the Mn oxides with the charge–discharge cycling number was studied using a scanning electron microscope (SEM), an atomic absorption spectroscope, and an X-ray photoelectron spectroscope, respectively. The analytical results indicate that the electrochemical stability of Mn oxide is mainly determined by its microstructure; the more fibrous (or porous) oxide had a greater durability against cyclic charge–discharge. Moreover, the chemically hydrous state was found to be the most crucial factor that governed the mass specific capacitance of Mn oxide.

On the swelling potential of compacted high plasticity clays

In earthworks engineering, predicting the influence of the water content and the dry density on compacted soils deformation is a fundamental issue, which is particularly important for the use of clays in embankments. This paper presents the experimental results and a microstructural interpretation of swelling tests performed on four clays, compacted at different water contents and dry densities. The influences of dry density and water content on the swelling potential are described, showing the coupled effect of these two parameters. In order to quantify this coupling, the initial air void ratio is defined and it is observed that this air void ratio has an apparent linear relationship with the void ratio after swelling. This observation enables analysing all the tests in a synthetic manner, by plotting the origin ordinate and the slope of the linear relationships versus the initial hydrous state. Moreover, one of the clays microstructure was analysed using mercury intrusion porosimetry (MIP). The results show that swelling leads to a micropores increase and a macropores decrease. In addition, micropores volume increase does not depend on the initial dry densities, whereas the macropores volume increase does. For further discussion, a simplified microstructural model is proposed allowing the interpretation of the soil swelling using MIP results. The comparison between the model prediction and the microstructure observation supports the interpretation of the swelling tests and shows that the origin ordinate and the slope of the relationship between the initial air void ratio and the final void ratio can be linked to micropores and macropores volume variations. However, the comparison also shows that the simplified microstructural model presents some limitations when applied to very dry or wet soils.

Charge storage mechanism of nanostructured anhydrous and hydrous ruthenium-based oxides

The charge storage mechanism of nanostructured anhydrous and hydrous ruthenium-based oxides was evaluated by various electrochemical techniques (cyclic voltammety, hydrodynamic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy). The effects of various factors, such as particle size, hydrous state, and structure, on the pseudocapacitive property were characterized. The electric double layer capacitance ( C dl), adsorption related charge ( C ad), and the irreversible redox related charge ( C irr) per unit mass and surface area of electrode material has been estimated and the role of structural water within the material either in micropores or interlayer are discussed.

Fine structure of hydrous chromosomes observed by low vacuum scanning electron microscopy.

Chinese hamster metaphase chromosomes were stained with platinum (Pt) blue and observed in the hydrous state with low vacuum scanning electron microscopes (LVSEM). The coiled structure of the chromatin fibers in the chromosomes was well recognized through the surrounding perichromosomal substances in the backscattered electron (BSE) mode at accelerating voltages of over 20 kV. Findings indicated that chromatin fibers in native chromosomes have a structure similar to the hierarchic coiled model. The present study also demonstrated that not only surface structures but also subsurface structures can be studied in the BSE mode of LVSEM, when the subsurface structures have been stained with heavy metal salts such as Pt blue.

Temperature-programmed reduction of Ni-Mo oxides

Temperature-programmed reduction (TPR) has been employed to study Ni-Mo mixed oxides which were previously used as model hydrodesulphurization (HDS) catalysts, using compositions ranging from pure MoO3 to pure NiO. An assignment of TPR signals to the different bulk phases was attempted. Good agreement between TPR spectra and structural data obtained previously from X-ray and electron diffraction was observed. TPR traces were consistent with proposed mechanisms of reduction of the bulk oxides MoO3, MoO2, NiO and NiMoO4. The variations in TPR spectra were interpreted in terms of effects such as crystallite size, ageing of the samples, hydrous state and chemical interactions between the different species. The significance of these reducibility results for HDS catalysis is discussed.

Utilisation d'indicateurs de l'état hydrique du sol dans un modèle pluie-débit

Researches concerning taking into account direct measures concerning the ground hydrous state in the flowrate forecast models have been carried out following a statistical study which demonstrated the full power of ground humidity as regards the yield function.This article covers the results obtained by means of a conceptual model with tanks simulating a continuous chronicle of an end time step flow and by measuring the benefit acquired by introducing humidity or potential data in the place of evaporation.

Optimisation of the Use of Water Reserves in Agriculture from the Modelling Water-Soil-Crop System

The aim of the study is the modelling of the water-soil-corn system from experimental data, which have been measured in full size expriments on various cultures over a period of ten years by the Agro station, in order to improve water use in agriculture. For various plots and several years, series of soil humidity at several depths (every 10 cm down to 1.6 m) have been gathered at various instants of the year (about 20 for each plot every year) .The application of systematic techniques of modelling and identification to this system allowed the build up of a model simulating the time histories of the hydrous state of a soil farmed in corn. The problems encountered lead to back up the classical model error identification method by statistical data analysis methods. Good results for the specific application considered (precision better than 10%) have been obtained by alternate and iterative use of both kinds of methods. It is then possible to calculate the detailed hydrous state of the soil (every 10 cm) from easily measured data, namely rain, potential evapotranspiration and some parameters characteristic of the soil and culture. This is particularly useful for the precise forecast of the days and volumes of irrigation for a better use of the available water.

The nature and origin of lamprophyres: some definitions, distinctions, and derivations

Lamprophyres are porphyritic dyke-rocks, readily recognisable in the field, which seemed to have become enveloped in petrological mystery because of their scattered and often contradictory literature. Important characteristics common to all members of this extremely heterogeneous group are suggested to include their intrusion at a late stage in any igneous event, the presence of essential amphibole or biotite coupled with peculiar chemistry, and their lack of felsic phenocrysts. Panidiomorphic texture is usual, though by no means exclusive to lamprophyres. At least four lamprophyre subgroups may be recognised; these are quite distinct in petrology, chemistry, paragenesis and petrogenesis although individual members of each subgroup are closely similar. The alkaline lamprophyre subgroup is considered in detail: new definitions of camptonite and monchiquite are proposed which are believed to reconcile majority usage whilst accomodating existing analytical data; the term ouachitite is reassessed and fourchite suggested to be superfluous; sannaite, an alkali feldspar-rich alkaline lamprophyre, may be more abundant than its frequency within the literature implies — some “minettes” and “vogesites” are more correctly termed sannaite, particularly those occurring in carbonatite complexes. Camptonites most probably represent alkali basalt magmas which became unusually hydrous through influence of an alkaline pluton, and then evolved at relatively low pressures. Varied evidence is considered to suggest that the nearly isotropic base in monchiquites typically consists of altered glass rather than analcime; where analcime is present it probably formed along with zeolites by secondary processes. “Monchiquitic” is not an appropriate synonym for “analcime-bearing”, as in some literature. Field, chemical and statistical evidence is taken to suggest that many monchiquites are either chilled heteromorphs of camptonites or camptonitic magmas which crystallised under high CO 2 activities. Liquid immiscibility seems to be more extensively developed in camptonites and monchiquites than in any other igneous rocks, and is probably governed by their hydrous state. The genetic connotations of lamprophyre names, asserted early in their history but later questioned, are here modified but reaffirmed: broadly minettes and related lamprophyres connote post-orogenic granites or mildly potassic (shoshonitic) alkaline rocks, alkaline lamprophyres connote alkali basalts or sodic alkaline rocks, and alnoites connote carbonatites.

Mantle beneath the Japanese arc

Seismic velocity structure of the mantle beneath Japan has been determined on the basis of teleseismic explosion, long-period surface wave, and dΔ/d t data. A marked difference in structure is found across the deep seismic plane which dips from the Pacific Ocean side towards the continent. The mantle on the continental side of the seismic plane has such low velocity and Q (≈80) as to require a partial melting in addition to a possible compositional change. The low velocity seems to be associated with the underlying earthquake activity. It is found that the lower bound of the low velocity zone is relatively abrupt; this also provides a favorable evidence for the partial melting. A clear later phase branch observed at 15° < Δ < 20° suggests a rapid velocity increase at depths 375 to 400 km. This rapid velocity increase can be attributed to the onset of the olivine-spinel phase change of (MgFe) 2SiO 4, if the temperature at 400 km depth is about 1300 °C. This low temperature may call for a hydrous state in the upper mantle in order to cause the partial melting. The earthquake energy release has a notable maximum around 400 km depth in Japan region. The coincidence of this depth with that of the rapid velocity increase suggests that the olivine-spinel phase change is in some way related to the generation of deep focus earthquakes.