Polysulfide-mediated solvation shell reorganization for fast Li+ transfer probed by in-situ sum frequency generation spectroscopy

Understanding of interfacial Li$^+$ solvation shell structures and dynamic evolution at the electrode/electrolyte interface is requisite for developing high-energy-density Li batteries. Herein, the reorganization of Li$^+$ solvation shell at the sulfur/electrolyte interface along with the presence of a trace amount of lithium polysulfides is verified by in-situ sum frequency generation (SFG) spectroscopy together with density functional theory (DFT) calculations. Both the spectroelectrochemical and DFT calculation results reveal a strongly competitive anion adsorption of the polysulfide anion additive against the pristine electrolyte anion on the sulfur cathode surface, reorganizing the interfacial local solvation shell structure facilitating rapid Li ion transfer and conduction. Meanwhile, the evolution of the SFG signals along with the discharging/charging cycle exhibits improved reversibility, indicating the transformation of the inner Helmholtz plane layer into a stable molecular-layer polysulfide interphase rather than a dynamic diffusion layer. Consequently, applications in practical Li-S batteries reveal the capacity and cycling stability of the corresponding cells are significantly enhanced. Our work provides a methodology using in-situ SFG for probing solvation reorganization of charge carriers at electrochemical interfaces

Instability Analysis of a Low-Angle Low-Expansive Soil Slope under Seasonal Wet-Dry Cycles and River-Level Variations

There were a small amount of obvious offsets at the bearing of bridge piers built on an artificial gentle canal bank terrace and many tensile cracks visible at the surface of the mortar block stones covering the terrace soil in several years following construction. To determine these reasons, a comprehensive site investigation and a wide variety of tests were implemented, which included geophysical tests, in situ tests, laboratory tests, pile integrity detection, and numerical analysis with the finite element method (FEM). The results revealed that the soil of the low-angle slope was the potentially low-expansive clay soil. The reduction in soil shear strength deriving from seasonal wet-dry cycles and river-level variations led to the instability and failure of the low-angle low-expansive soil slope, which triggered the collapses of the soil slope and lots of fractures in the piles of the bridge foundation. The typical characteristics of the instability and failure of the low-angle low-expansive soil slope were tractional detachment and slow sliding

The Influence of Soil Disintegration in Water on SlopeInstability and Failure

The instability of the bank slope of the reservoir will cause great loss to the life and property of the people in the reservoir area. The landslide of the reservoir not only occurs in the period of water level plummeting, but also occurs in the period of water level rising. In this paper, the mechanism of slope landslide in the rising stage of water level was studied from the perspective of soil disintegration in water. A series of tests on the disintegration of prisms and cylinders with the same volume and different bottom side lengths (diameter) were carried out. The results show that the specific surface area of the same volume sample was different, and the disintegration behavior was different. The larger the specific surface area of the same shape sample was, the faster the disintegration speed was. The deeper the water depth was, the shorter the disintegration time was under the same initial conditions. It shows that when the water level of the reservoir rose, the deeper the water depth was, the greater the pore osmotic pressure was, and the more the soil mass of the slope collapsed. This led to the reduction of the pressure on the lower part of the slope, the decrease of the antisliding force of the soil, and the failure of the slope

Numerical study on the smoke movement and control in main roadway for mine fires occurred in branch

Mine exogenous fire is the main disaster in coal mines. Owing to the complicated structure and the ventilation network, the smoke movement and control in branched roadway fires of coal mines is more complicated than that in traffic tunnel fires. In this study, the smoke backlayering length and critical velocity in a main roadway for fires that occurred in a branch were studied with varying fire locations. The results suggest that the smoke from the branch does not spread along the width centerline of the main roadway, but forms an early “snake-shaped” structure. The variation of dimensionless backlayering length with the dimensionless variable ln(Q˙*1/3/V*) is divided into two regions with different slopes by the line of L* = 1.6. Besides, branched roadway fires have a lower backlayering length and critical velocity compared to single-hole tunnel fires. These two parameters increase with decreasing the fire-node distance. Combined with dimensionless analysis and simulation results, calculation models considering fire location were proposed to estimate the smoke backlayering length and critical velocity. The credibility of prediction models is validated by comparing them with simulation results. The outcomes of the current study guide smoke control in similar-structured mine roadways and traffic tunnels

Optimizing sludge dewatering efficiency with ultrasonic Treatment: Insights into Parameters, Effects, and microstructural changes

Sludge dewatering plays a critical role in the efficient and cost-effective management of wastewater treatment plants. Ultrasonic treatment has emerged as a promising technique for improving dewatering processes. This study aims to evaluate the impact of ultrasonic treatment on sludge dewatering characteristics. A series of experiments were conducted to evaluate the dewatering characteristics of sludge under ultrasonic treatment. Experimental data was collected, and the effects of ultrasonic parameters on dewatering efficiency were analyzed. Ultrasound has the capacity to disintegrate sludge flocs, liberate tightly bound water, and enhance sludge dewatering capabilities. The application of ultrasound leads to the breakdown of sludge flocs, which facilitates a substantial amount of organic acids or carbonates. This, in turn, modifies the pH value of the sludge. Additionally, ultrasound induces instantaneous high temperature and pressure within the liquid phase, consequently elevating the temperature of the sludge slurry. Optimum ultrasound energy density and duration of ultrasound treatment exist. For the sludge samples analyzed in this investigation, it was determined that the optimal ultrasonic energy density is 9.8 W, while the optimal duration of ultrasound treatment is 30 s. Excessively escalating the sound energy density or prolonging the duration of ultrasound may yield unfavorable outcomes in terms of sludge dewatering effectiveness. To enhance sludge dewatering, it is crucial to select appropriate ultrasonic energy density and duration of ultrasonic treatment. This study demonstrates the positive impact of ultrasonic treatment on the dewatering characteristics of sludge. The findings provide valuable insights into the potential of ultrasonic technology for enhancing sludge dewatering

Desalinization and salinization: a review of major challenges for coastal reservoirs

Coastal reservoirs are a possible solution to water supply and management issues in coastal zones. However, salinization can degrade the utility of such reservoirs. Two related major challenges affecting the operation of a coastal reservoir are desalinization and seawater intrusion. The former arises mainly during the period following reservoir construction, while the latter is ongoing. This review discusses the salt dynamics of coastal reservoirs under the influence of surface-water flows, river inflows, reservoir water level, and tides. Various salt transport processes are examined in relation to water salinity changes in coastal reservoirs. The methods and limitations of existing numerical models for coastal reservoirs are also discussed. Given the difficulty in reproducing realistic boundary conditions for laboratory experiments, further research needs to focus on investigations that consider salinization in real coastal reservoirs. More broadly, there remains a need to unravel the impacts of coastal reservoirs on the surrounding environment, as they can significantly change the hydrodynamics and chemical transport pathways in coastal waters. A comprehensive understanding of coastal reservoir salinization will improve water management and thus contribute to alleviating overexploitation of water resources in coastal zones

Stable propagation of the Poincaré polarization solitons in strongly nonlocal media

We report the first experimental observation of spatial solitons with complex polarization states, called the Poincaré polarization solitons (PPSs) in lead glass with strongly nonlocal nonlinearity. The formations of PPSs with topological charge of l  = 1, including the cylindrical elliptical-polarization soliton (CEPS) and the angularly-hybrid polarization soliton (AHPS), were observed. We showed that the annular profiles and the complex polarization distributions of the first-order PPSs can be remained. Based on the linear stability analysis, we proved that the first-order PPSs are fully stable and the second-order PPS can survive only when one of the two component vortices dominates

Quality and Metabolomics Analysis of Houttuynia cordata Based on HS-SPME/GC-MS

Houttuynia cordata is a medicinal and edible plant with a wide biological interest. Many parts were discarded due to various modes of consumption, resulting in resource waste. In this study, a comprehensive study was conducted on various edible indicators and medicinal components of Houttuynia cordata to understand its edible and medicinal value. The edible indexes of each root, stem, and leaf were determined, and the metabolites of different parts were investigated using the headspace solid-phase micro-extraction technique (HS-SPME-GC-MS). The differential metabolites were screened by orthogonal partial least squares discriminant analysis (OPLS-DA) and clustering analysis. The results of the study showed that the parts of Houttuynia cordata with high edibility values as a vegetable were mainly the roots and leaves, with the highest vitamin C content in the roots and the highest total flavonoids, soluble sugars, and total protein in the leaves. The nutrient content of all the stems of Houttuynia cordata was lower and significantly different from the roots and leaves (p < 0.05). In addition, 209 metabolites were isolated from Houttuynia cordata, 135 in the roots, 146 in the stems, 158 in the leaves, and 91 shared metabolites. The clustering analysis and OPLS-DA found that the parts of Houttuynia cordata can be mainly divided into above-ground parts (leaves and stems) and underground parts (roots). When comparing the differential metabolites between the above-ground parts and underground parts, it was found that the most important medicinal component of Houttuynia cordata, 2-undecanone, was mainly concentrated in the underground parts. The cluster analysis resulted in 28 metabolites with up-regulation and 17 metabolites with down-regulation in the underground parts. Most of the main components of the underground part have pharmacological effects such as anti-inflammatory, anti-bacterial and antiviral, which are more suitable for drug development. Furthermore, the above-ground part has more spice components and good antioxidant capacity, which is suitable for the extraction of edible flavors. Therefore, by comparing and analyzing the differences between the edible and medicinal uses of different parts of Houttuynia cordata as a medicinal and food plant, good insights can be obtained into food development, pharmaceutical applications, agricultural development, and the hygiene and cosmetic industries. This paper provides a scientific basis for quality control and clinical use

Test and Analysis of Sludge Dewatering with a Vacuum Negative Pressure Load at the Bottom of Full Section

At present, the sludge production has increased sharply, and sludge treatment remains a serious problem. Rapid sludge dewatering is the key problem of sludge treatment, and the main approach for reducing the cost of the sludge treatment is to reduce the cost of sludge dewatering. In this paper, two groups of sludge dewatering tests were carried out using homemade instruments and equipment. One group was conducted without rice straw, and the other group was conducted with rice straw. The relevant mechanism was analyzed, and the results indicate that sludge dewatering with a vacuum negative pressure load of the full section at the bottom is better than mechanical sludge dewatering. The sludge dewatering effect with rice straw is better than that without rice straw. Additionally, the vacuum degree inside the sludge decreased sharply. The pore water pressure slowly dissipates during the early and late stages and quickly during the middle stage. Sludge pore water seepage does not obey Darcy’s law, and sludge dewatering is intermittent