Clioquinol Research Articles

High temperature corrosion and oxide scale formation of nickel in molten NaOH at various basicity levels

The corrosion behavior of alloy Ni 201 in molten sodium hydroxide (NaOH) at 600 °C was investigated at varying basicity levels of the molten NaOH. The ability for Ni 201 to form passivating oxides was investigated after immersion tests varying from 70 to 340 h under atmospheres of argon and argon with different partial pressure of water. Morphology and thicknesses of the corrosion products were characterized by Scanning Electron Microscopy (SEM) and crystallography of the corrosion products by X-ray Diffraction (XRD). Dynamic polarizations were made to investigate the effects of basicity and electrochemical potential.The results showed that Ni 201 corroded at a reduced rate in molten acidic NaOH compared to neutral NaOH due to the formation of NiO. The oxide scales formed on Ni 201 in acidic NaOH were shown to grow non-parabolically and did not result in full corrosion protection as the oxide scales showed crack development over time.

Electrochromic Thin‐Film Nickel‐Oxide Coatings for Systems with Adjustable Light Transmission

In this study, results on the effect of technological parameters of the nickel(II)‐oxide thin‐film deposition process, obtained through chemical vapor deposition in an argon–oxygen environment using bis‐(ethylcyclopentadienyl)‐nickel (EtCp)2Ni, on their electrochromic properties, are presented. It is shown that the films lose ability to electrochromic coloring in alkaline environments as their thickness increases up to 170 nm. The introduction of small ozone additions of 0.1 vol% O3 into the gas phase leads to a decrease in the NiO films deposition rate, the formation of a rougher layer with an average grain size up to 71.4 nm, capable of coloring in light brown. Additional cathodic treatment of NiO films at a potential of −0.8 V for 30 s in alkaline environments containing fullerene C60(OH)24 leads to the modification of the surface layer and the formation of NiO–C carbon‐containing nanocomposite coatings with enhanced contrast and the ability to retain the colored state after polarization is turned off, i.e., possessing optical memory properties. Using NiO–C nanocomposite and indium–tin–oxide films, which have opposite coloring mechanisms, in the structure of an electrochromic device allows for an increase in the grade of glass darkening, significantly reducing energy consumption, improving operational characteristics, and life span.

Enhancement in supercapacitive performance of calcium phosphate nanoneedles through Ni-ion incorporation: Insights into atomic and electronic structures

Phosphates have emerged as promising materials for electrochemical charge storage applications. However, a comprehensive understanding of their storage mechanism remains elusive. The present work reports the impact of nickel ion doping on hydroxyapatite (PH) prepared by a wet-chemical route. X-ray diffraction (XRD) reveals the formation of NiO and Raman and Fourier-transform infrared (FTIR) analyses demonstrate the suppression of phosphate modes on doping. The incorporation of Ni ions induces nanoneedles morphology, effectively engineering the surface area and volume of the material. Notably, specific capacitance significantly improves to 415.35 Fg-1 at 10 mAg−1 for Ni-incorporated PH (0.1 M of Ni) (0.1NH), a remarkable enhancement compared to 166.77 Fg-1 at 10 mAg−1 for pristine (PH). X-ray photoelectron spectroscopy (XPS) confirms the mixed valence state of Ni2+/3+ and the presence of Ni–O bonding on Ni incorporation. Moreover, X-ray absorption spectroscopy (XAS) reveals the formation of Ni–O–Ni clusters, enhanced charge transfer by Ni ions, and optimized coordination of Ni–O bonds. The comprehensive correlation established between the phase, morphology, and electronic and local atomic structures elucidates the excellent electrochemical charge storage performance. This investigation sheds light on the potential of Ni-doped hydroxyapatite as a promising material for electrochemical applications, contributing valuable insights for the design and optimization of advanced energy storage systems.

Antifungal activity of azoles, allylamines, and 8-hidroxiquinolines, alone and in combination, against Malassezia pachydermatis in vitro and in vivo

Malassezia pachydermatis is often reported as the causative agent of dermatitis in dogs. This study aims to evaluate the in vitro and in vivo antifungal activity of azoles and terbinafine (TRB), alone and in combination with the 8-hydroxyquinoline derivatives (8-HQs) clioquinol (CQL), 8-hydroxyquinoline-5-(n-4-chlorophenyl)sulfonamide (PH151), and 8-hydroxyquinoline-5-(n-4-methoxyphenyl)sulfonamide (PH153), against 16 M. pachydermatis isolates. Susceptibility to the drugs was evaluated by in vitro broth microdilution and time-kill assays. The Toll-deficient Drosophila melanogaster fly model was used to assess the efficacy of drugs in vivo. In vitro tests showed that ketoconazole (KTZ) was the most active drug, followed by TRB and CQL. The combinations itraconazole (ITZ)+CQL and ITZ+PH151 resulted in the highest percentages of synergism and none of the combinations resulted in antagonism. TRB showed the highest survival rates after seven days of treatment of the flies, followed by CQL and ITZ, whereas the evaluation of fungal burden of dead flies showed a greater fungicidal effect of azoles when compared to the other drugs. Here we showed for the first time that CQL is effective against M. pachydermatis and potentially interesting for the treatment of malasseziosis.

Finite strain, kinematic vorticity, rheological behavior and thermochronology of the Diancang Shan complex: Insights into channel flow of the southeastern Tibetan plateau

This study investigates the crustal flow within the southeastern orogenic belt of the Tibetan Plateau, with a focus on the Diancang Shan (DCS) complex. As an A-type gneiss dome, the DCS complex offers valuable insights into the deformation and evolution of intra-continental orogenic belts and the flow of deep crustal material. We have identified three main stages of deformation within the DCS complex since the Cenozoic. The initial stage (D1), spanning 41–30 Ma, was characterized by high-temperature pure shear deformation, which developed penetrative foliations, symmetric folds, and structural lenses. The subsequent major stage (D2), which shaped the overall architecture of the DCS complex from approximately 27–21 Ma, was primarily influenced by strike-slip stress regimes, resulting in shear fabrics with a top-to-the SE orientation in the releasing bend. The final stage (D3), initiated around 13 Ma, was marked by retrograde metamorphism at lower temperatures. Kinematic vorticity calculations indicate that the D1 stage was dominated by pure shear, while the D2 stage was primarily influenced by simple shear. The deformation temperature for the major deformation stage (D2) is estimated to range between 450 and 550 °C. During this stage, strain rates lie between 10−13–10−16 s−1 at 450 °C and 10−12–10−14 s−1 at 550 °C, indicating relatively low strain rates within the DCS complex. Our findings suggest that the formation of the DCS dome can be attributed to the ductile extrusion of channel flow, driven by the gravitational collapse of the Tibetan Plateau. Partial melting of the thickened middle and lower crust may have provided the channels and material sources. Furthermore, shear strain analysis (0.15–0.49) indicates that pure shear played a more significant role, contributing ∼ 65 % to the formation of the DCS dome.

Induction of IFIT1/IFIT3 and inhibition of Bcl-2 orchestrate the treatment of myeloma and leukemia via pyroptosis

Induction of pyroptosis is proposed as a promising strategy for the treatment of hematological malignancies, but little is known. In the present study, we find clioquinol (CLQ), an anti-parasitic drug, induces striking myeloma and leukemia cell pyroptosis on a drug screen. RNA sequencing reveals that the interferon-inducible genes IFIT1 and IFIT3 are markedly upregulated and are essential for CLQ-induced GSDME activation and cell pyroptosis. Specifically, IFIT1 and IFIT3 form a complex with BAX and N-GSDME therefore directing N-GSDME translocalization to mitochondria and increasing mitochondrial membrane permeabilization and triggering pyroptosis. Furthermore, venetoclax, an activator of BAX and an inhibitor of Bcl-2, displays strikingly synergistic effects with CLQ against leukemia and myeloma via pyroptosis. This study thus reveals a novel mechanism for mitochondrial GSDME in pyroptosis and it also illustrates that induction of IFIT1/T3 and inhibition of Bcl-2 orchestrate the treatment of leukemia and myeloma via pyroptosis.

Disentangling the Unprecedented Yangtze River Basin Extreme High Temperatures in Summer 2022: Combined Impacts of the Reintensified La Niña and Strong Positive NAO

Abstract During July and August of 2022, the Yangtze River Basin (YRB) experienced its most extreme high temperature (EHT) event since 1979, resulting in large numbers of human casualties and severe economic losses. This paper reveals the spatial and temporal features of the EHT over the YRB (YRB-EHT) in 2022 and disentangles its extreme nature from a historical perspective. Results showed the following: 1) The record-breaking YRB-EHT was directly caused by the adiabatic heating associated with an anomalous barotropic high pressure (or heat dome) and descending motion in the region. The intensified and westward-shifted western North Pacific subtropical high and eastward-extended South Asian high played critical roles in the formation of the heat dome and descending motion anomaly. 2) Convection anomalies over the tropical Atlantic and Pacific induced by the reintensified La Niña–like Pacific sea surface temperature anomaly pattern, along with the strong positive North Atlantic Oscillation (NAO), were the key contributing factors to the formation of the barotropic high pressure anomaly and YRB-EHT. 3) A physics-based empirical simulation model constructed using the factors of the NAO and tropical convection successfully reproduced the historical year-to-year variation of YRB temperatures, as well as the extreme in 2022, implying that the unprecedented 2022 YRB-EHT had universal dynamic origins. This study highlights the importance of the combined impacts of tropical and extratropical forcings in the record-breaking YRB-EHT in 2022, and thus may provide useful clues for seasonal predictions of summer mean or extreme temperatures in the YRB. Significance Statement Extreme high temperatures hit the Yangtze River Basin (YRB) in summer 2022, causing large numbers of human casualties and severe economic losses. Here, from a historical perspective, we disentangle the dynamic origins of these high temperatures over the YRB. Based on evidence from both observations and model simulations, the present study highlights the importance of the combined impacts of tropical and extratropical routes of influence on these extremely high temperatures in the YRB, and thus may provide useful clues for seasonal predictions of YRB summer mean or extreme temperatures.

Analytical Study of Structural Conformation and Prestressing State of Drum-Shaped Honeycomb Quad-Strut Cable Dome Structure with Different Calculation Methods

Building upon the analytical study of the structural configuration and prestress state of the drum-shaped quad-strut cable dome, we conducted further investigation into its structural configuration. By employing the nodal equilibrium equations to solve the prestress state analysis of the cable dome, we compared the effects of two different cable laying methods on the prestress state of the cable dome structure. These methods include equal length of the radial horizontal projection of the upper chord ridge cables and equal radial chord length of the upper chord ridge cables. The analysis results show that the radial length of the top chord and its corresponding radial horizontal projection length of the cable dome structure can effectively reflect the trend of the prestress state of the structural configuration. Furthermore, by using a rise-to-span ratio of 0.11 as a threshold, the cable dome configuration is categorized into the flat spheroidal structural configuration and the small hemispheroidal structural configuration. When the structure is analyzed using a small rise-to-span ratio, the difference in prestress calculations between the two structural configurations is found to be less than 10%. Additionally, the structure exhibits a more uniform distribution of prestress, with the prestress gradually increasing from the inner circle to the outer circle. However, when the rise-to-span ratio increases, the difference between the prestress calculation results of the two configurations also increases, emphasizing the need to deploy upper chord ridge cables based on equal radial chord lengths (arc lengths). The research presented in this paper provides a novel insight into the structural topological form and prestress state calculation of cable domes with this configuration.

Zinc dampens antitumor immunity by promoting Foxp3+ regulatory T cells.

The role of zinc (Zn) in tumor development and immune modulation has always been paradoxical. This study redefines our understanding of the impact of Zn on cancer progression and therapeutic strategies. We investigated the effects of dietary Zn levels on tumor progression and immune responses. This included examining the impact of both high and deficient dietary Zn, as well as Zn chelation, on tumor growth and immune cell populations. Specifically, we analyzed the frequency of Foxp3+ regulatory T-cells (Tregs) and identified the role of FOXO1 in Zn-mediated effects on Tregs. Additionally, we explored the therapeutic potential of clioquinol (CQ) in enhancing α-PD-1 immunotherapy responses, particularly in melanoma. Our findings show that high dietary Zn promotes tumor progression by fostering a protumorigenic environment mediated by T cells. Increased Zn intake was found to facilitate tumor progression by increasing Foxp3+ Treg frequency. In contrast, deficiency in dietary Zn and chelation of tissue Zn emerged as potent drivers of antitumor immunity. We pinpointed FOXO1 as the master regulator governing the influence of Zn on Tregs. These results reveal a novel mechanistic insight into how Zn influences tumor progression and immune regulation. The identification of FOXO1 as a key regulator opens new avenues for understanding the role of Zn in cancer biology. Furthermore, we introduce a promising therapeutic approach by showing that administering clioquinol (CQ) significantly enhances α-PD-1 immunotherapy response, particularly in melanoma. These revelations transform our comprehension of the multifaceted role of Zn in tumorigenesis and immune regulation, highlighting innovative possibilities for cancer therapy.

Particle clogging mechanisms in hyporheic exchange with coupled lattice Boltzmann discrete element simulations

The clogging of a stream bed has a significant impact on the exchange of water between a river and groundwater, known as hyporheic exchange. Clogging issues in orifices influenced by fluid flow have long been a concern, particularly in understanding clogging mechanisms and particle dynamics. This study focuses on investigating the behavior of poly-dispersed particle systems in the Shanghai soft soil using a coupled lattice Boltzmann method and a discrete element method (LBM-DEM). A particle-orifice model was developed based on LBM-DEM to study the clogging problem. Three different orifice diameters with the same particle size distribution were set at a microscopic scale. The simulation results indicate that the primary form of clogging is the formation of particle domes, exhibiting distinct characteristics depending on orifice size. As the orifice size increases, clogging becomes more challenging. Interestingly, the flow rate of fluid passing through clogged orifices is quite complex, as it does not decrease significantly. The formation process of the particle structure shows significant randomness, posing challenges for quantitative analysis and experimental validation. This study provides insights into the initial stages of clogging formation, leading to a better understanding of hyporheic exchange phenomena in stream bed ecosystems.

Formation of the Naxos nested domes and crustal differentiation by convection and diapirism

The Naxos dome, in the middle of the Aegean domain, exposes the former root of the Alpine orogenic belt and represents a key natural example to investigate the development of gravitational instabilities during orogenic evolution and their impact on crustal differentiation. The Naxos dome is cored by migmatites with structures depicting second order domes with a diameter of 1–2 km nested in the first order deca-kilometer scale dome that formed at the onset of orogenic collapse. Zircon grains from the migmatites record a succession of crystallization-dissolution cycles with a period of 1–2 Myr. These features have been attributed to the development of convective and diapiric gravitational instabilities, related to thermally induced and compositional buoyancy. In this paper, we test the pertinence of this model with a thermal-mechanical numerical experiment performed with a volume of fluid method (VOF) known to preserve material phase interfaces during large deformation of viscous layers. Partial melting of the crust is modeled by strain-rate and temperature dependent viscosity and temperature dependent density. Moreover, horizontal layers with density, viscosity and heat production variations mimic more felsic or more mafic lithologies in a crust of intermediate composition. With basal heating, gravitational instabilities initiate with local segregation of the buoyant versus heavier layers, followed by diapiric upwelling of buoyant pockets of aggregated less dense material. Convection starts after 5 Myr, approximately when half of the crust has a viscosity lower than 1019 Pa s. The size of the convection cells increases as the temperature rises in the crust and reaches ∼25 km in diameter after ca. 20 Myr, which defines the size of first order domes. Some of the heterogeneous material is entrained in the convection cells with a revolution period of 1 to 3 Myr. However, most of the denser material accumulates in the lower crust, while the buoyant material segregates at the top of the convection cells and forms diapirs that correspond to second order domes, of several kilometers in diameter and nested within the first order domes. This model, which reproduces the first order characteristic dimensions of the Naxos nested domes and the periodicity of their zircon geochronological record, demonstrates the efficiency of gravitational instabilities in the formation of migmatite domes and, more generally, in the multi-scale dynamics of crustal differentiation leading to a felsic upper crust, an intermediate middle crust and a mafic lower crust.

Improving the desorption properties of LiAlH4 by the addition of Ni0.6Zn0.4O

Lithium alanate (LiAlH4) is one of the most preferred materials for solid-state hydrogen storage materials owing to its relatively high hydrogen capacity (10.5 wt%). However, its high decomposition temperature and sluggish desorption kinetic restrict its potential application as a hydrogen storage medium for on-board hydrogen-powered applications. To overcome these problems, the impacts of Ni0.6Zn0.4O synthesized via a solid-state method on the desorption properties of LiAlH4 have been examined in this study. It was found that after the introduction of 10 wt% of Ni0.6Zn0.4O to LiAlH4, hydrogen started to release at 124 °C and 170 °C for the first two stages, respectively. Isothermal desorption kinetics also revealed that faster desorption kinetics can be observed at 90 °C for 120 min LiAlH4+10 wt% of Ni0.6Zn0.4O can desorb 3.1 wt% of H2, whereas undoped LiAlH4 can release approximately less than 0.5 wt% of H2 in the same time frame. According to the Kissinger method, the apparent activation energies for the first two steps of the LiAlH4+10 wt% of Ni0.6Zn0.4O composites have been found to be 73 kJ/mol and 85 kJ/mol, respectively, 32 kJ/mol and 40 kJ/mol less than milled LiAlH4. The in-situ formation of NiO and Zn or Zn-containing compounds during the heating process might contribute to the kinetic improvement of LiAlH4.

МОДЕЛЮВАННЯ НАПРУЖЕНО-ДЕФОРМОВАНОГО СТАНУ МЕТАЛЕВОГО СТРИЖНЕВОГО КАРКАСУ ГЕОДЕЗИЧНОГО КУПОЛУ ДЛЯ РАЦІОНАЛЬНОГО ПРОЕКТУВАННЯ

The paper contains the further developed of method for calculating thin-walled shells with supporting frame in the form of geodesic domes without a stationary foundation. Have been performed the detailed analysis of the fundamental design solutions of frame demountable domes with tent double-layer cover, the inner layer of which serves as a projection screen of three-dimensional cinemas, which are gaining popularity in the amusement industry. Have been developed highly detailed finite element models of dome with a base diameter of 13.5 m, taking into account technological holes and structural elements of rigidity under the influence of wind, snow, ice and other climatic influences. Have been modeled at the same time, various options for connecting the dome frame to the base. Have been proven that the worst influence on the dome structures is the wind influence, based on the stability criterion. Have been proven at also that the frame-rod tented construction of the geodome cannot function safely without reliable connection to the base. Have been identified, areas of the core elements of the frame with the highest internal stresses from various loads for all possible options for connecting the frame to the base. Have been considered the general nature of deformation and possible destruction of the structure, as well as the issue of loss of stability. Have been founded that the most stressed structures include the tent cover and bolted fasteners of the joints of the rod system. Have been proposed a rational method for anchoring frame dome structures at temporary earthen construction sites using geo-screws or metal screw piles. Have been proven the possibility of anchoring the supporting elements of the dome in five polar symmetrical points using ballast. Have been formulated the constructive recommendations regarding the rational design of frame dome systems. Have been developed the technological regulations for the further safe operation of frame geo-domes, and have been outlined the directions for further scientific research on this topic.

Formation of nano-wire and ring-like microstructures in LC media via self-assembly of NiO quantum dots and investigation of their optoelectronic properties

Nickel oxide nano-dot wire and ring like structures were synthesized via self-assembly of nickel-oxide quantum dots in the presence of liquid crystal media. The sizes of the ring-like microstructures extend up-to a few tens of microns. After doping NiO QDs in 4-(trans-4-n-hexylcyclohexyl) isothiocyanatobenzoate (6CHBT), we characterize the LC and quantum dot hybrid system using optical microscopy, fluorescence, UV–vis-nir, FTIR, FESEM-EDX and Raman spectroscopy methods. The sizes of the synthesized NiO QDs are observed in the range of 5.38 nm–10.17 nm. Our FTIR data confirms for the purity as well as the nonbonding interactions of NiO NPs and LC molecules with each other. We have used theoretical models based on nanoscale principles to further validate our experimental findings. The predictive theoretical model match with the experimentally obtained particle size data and the corresponding band gap values for the case of spherical NiO nanoparticles very well. The band gap value of the hybrid system corresponds to spherical nanoparticle clusters of sizes 25 nm. This allows us to estimate the effective size of the nanoclusters of NiO QDs in the hybrid system. We have correlated the findings of fluorescence, Raman and optical microscopy to verify the formation of nanodot wires and nanodot-ring like microstructures in LC media. FESEM images further confirm for the formation of NiO nanodot-wire-like structures and presence of LC molecules anchoring over nano-dot hierarchical structures. Elemental analysis done using EDX, confirm for the presence of LC molecules and NiO.

Oblique rifting triggered by slab tearing: the case of the Alboran rifted margin in the eastern Betics

Abstract. The tectonic evolution of highly oblique continental margins that result from extension above lithospheric subduction–transform edge propagator (STEP) faults is poorly understood. Here, we investigate the case of the Alboran margin in the eastern Betics characterized by crustal thinning of 15–10 km, oblique to the direction of slab retreat. The current deformation patterns indicate that oblique rifting is underway. However, it is unclear whether these conditions are those that prevailed during the formation of the metamorphic domes and intramontane basins. We review the temporal and spatial evolution of Neogene sedimentary basins and brittle deformation in the eastern Betics and exploit offshore seismic reflection lines to propose a crustal-scale section across the oblique margin. The history of sediment infill and rates of subsidence combined with the analyses of fault slip data confirm that brittle extension oriented from north 20∘ E to E–W occurred during an interval spanning from the Serravallian–early Tortonian to the late Tortonian (14–8 Ma). This extension is associated with both normal and strike-slip regimes and the evolution of the strike-slip fault zones flanking the metamorphic domes. The transtensional model forms a coherent scheme linking the ductile deformation associated with metamorphic domes and the formation of E–W- and NW–SE- or NNW–SSE-directed sedimentary basins in the brittle upper crust during the Tortonian. The oblique extension, which is closely associated with STEP faulting, occurred during the regional convergence between Africa and Iberia since the Miocene. Only recently, around 8 Ma, has slab detachment started to migrate westward, leading to tectonic inversion in the eastern Betics. Such a type of narrow oblique-rifted margin associated with transform-like plate boundaries is not unique but is expected to be hardly preserved in the geological record due to the transient nature of retreating subduction systems.

Mechanical properties of epithelial cells in domes investigated using atomic force microscopy.

As epithelial cells in vitro reach a highly confluent state, the cells often form a microscale dome-like architecture that encloses a fluid-filled lumen. The domes are stabilized by mechanical stress and luminal pressure. However, the mechanical properties of cells that form epithelial domes remain poorly characterized at the single-cell level. In this study, we used atomic force microscopy (AFM) to measure the mechanical properties of cells forming epithelial domes. AFM showed that the apparent Young's modulus of cells in domes was significantly higher when compared with that in the surrounding monolayer. AFM also showed that the stiffness and tension of cells in domes were positively correlated with the apical cell area, depending on the degree of cell stretching. This correlation disappeared when actin filaments were depolymerized or when the ATPase activity of myosin II was inhibited, which often led to a large fluctuation in dome formation. The results indicated that heterogeneous actomyosin structures organized by stretching single cells played a crucial role in stabilizing dome formation. Our findings provide new insights into the mechanical properties of three-dimensional deformable tissue explored using AFM at the single-cell level.

Probing the (de)activation of Raney nickel–iron anodes during alkaline water electrolysis by accelerated deactivation testing

We investigated the (de)activation of Raney nickel–iron anodes in various oxygen evolution reaction (OER) environments using accelerated deactivation testing (ADT) under the conditions of on/off voltage control (ADT1), constant current density (ADT2), and cyclic voltammetry (ADT3). ADT1 caused activation under OER conditions by promoting the leaching of residual zinc and thus increasing the electrode surface area and oxygen vacancy content, whereas deactivation was observed under the conditions of the hydrogen evolution reaction(H-ADT1). ADT2 decreased the OER activity by promoting NiO formation and iron leaching, while ADT3 slightly increased the OER activity by favoring the incorporation of iron into the nickel lattice and promoting nickel–iron hydroxide formation. Thus, this work facilitates the design of more efficient and durable Raney nickel–based OER anodes by providing insights into their (de)activation mechanisms.

Theoretical justification of the assessment of contamination of surface water resources by underground runoff as a result of military operations

Military actions on the territory of Ukraine cause a negative impact on the quality of water resources due to the ingress of contaminated effluents into underground horizons due to the destruction and/or damage of treatment facilities. This work deals with the definition of theoretical approaches to the quantitative assessment of pollution entering surface water resources through underground feeding due to damage to protective screens in ponds, storage tanks of various types and tailings storage facilities. The spread of contamination in case of screen damage was noted in three stages: wetting of the aeration zone from the damaged lining to the surface of the underground flow; non-stationary rise in the groundwater level with the formation of a water dome; became filtering in the direction of discharge of underground flow. The problem of the loss of piezometric head during the passage of the filtration flow through the screen structure and the determination of the flow of polluted water from the specified structure based on this value are considered. An analytical solution to the problem of wetting the aeration zone from the damaged lining to the surface of the pressureless underground flow is given. Taking into account the increase in the permeability coefficient of the screen due to damage, increased cracking, gusts, it was established that if its value is greater than or equal to 1.0*10-2m/day, the effect of screen protection can be ignored, and the filtration costs can be calculated according to the well-known infiltration formulas from unlined sewage treatment plant. The proposed approaches at different stages of filtration losses from the sewage treatment plant may in the future form the basis of the development of methods for calculating the migration of pollutants, taking into account the various sources of their entry into the groundwater, depending on the degree of damage to the shielded sewage treatment facilities.

Fragmentation behavior of young pyroclasts from Mt. Pelée, Martinique

The stratovolcano Mt. Pelée, Martinique, exhibits eruptive styles ranging from dome formation to sustained, highly violent explosive activity. Historical eruptions have produced lava domes and pyroclastic density currents, collectively termed Peléan activity. In pre-colonial times, several Plinian eruptions took place. Here, we explore physical controls on the proportions of fine particles produced—i.e., the fragmentation efficiency—during primary fragmentation. Samples were collected from ignimbrites from the 1929–1932 and 1902–1905 Peléan eruptions and the P1 (1300 CE), P2 (280 CE), and P3 (79 CE) Plinian eruptions. All samples are andesitic in bulk composition and contain a rhyolitic groundmass glass. The Peléan materials are more crystalline and less porous than their Plinian counterparts, a consequence of more extensive outgassing during dome formation. Representative blocks were cored and experimentally fragmented following rapid decompression (> 1 GPa·s−1 from initial pressure between 5 and 20 MPa). Dry sieving allowed for determining grain size distributions, from which the fractal dimensions, Df, were calculated as a quantification of fragmentation efficiency. Our results indicate different behaviors for Peléan and Plinian samples. While fragmentation efficiency is positively correlated with applied potential energy for Peléan samples, this relationship is not observed for the Plinian samples, possibly due to syn-fragmentation gas escape above a certain porosity. The rapid decompression experiments were designed to minimize secondary fragmentation by shear along the walls or impact while preserving the entirety of produced materials. Thus, our experimental grainsize data are physically linked to sample textures and overpressure. By comparison with natural pyroclastic products—commonly incompletely preserved—we can approach quantitatively constraining the energetic conditions underlying individual eruptions.

Convection and segregation in heterogeneous orogenic crust with a VOF method – II: how to form migmatite domes

SUMMARY Migmatites and granitic-gneisses exhumed in Archean to Phanerozoic segments are former partially molten crustal roots, display typical domes structures ranging in size from kilometres to decakilometres, and are often interpreted as resulting from the development of diapiric or convective gravitational instabilities. In previous work (part I), we determined various regimes of gravity-driven segregation, by considering a thick continental crust heated from below and containing melt related heterogeneities. These heterogeneities, represented by inclusions of distinct densities and viscosities with respect to the ambient partially molten material, can be entrained into convection cells (in the ‘suspension’ and ‘layering’ regimes) and/or accumulate as clusters (in the ‘layering’ and ‘diapirism’ regimes). Here we further investigate the specific conditions that allow for the formation and preservation of domes resulting from diapirism at the top of convective cells. We show that both the cessation of basal heating and the freezing of the buoyant inclusions density favour their stacking and preservation at ca. 15 km depth, within about 10 Myr. The buoyant inclusions form domes, 5–20 km in size, that also record several convective cycles at velocities ranging from 0.5–4 cm yr−1. 3-D models demonstrate their radial geometrical nature. The influence of the size and concentration of the inclusions is also assessed, complementing the characteristics of crustal heterogeneity in driving its differentiation and the formation of migmatite domes.