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Enhancing boundary slip using interfacial nanobubbles (INBs) has gained significant interest in nanofluidic transport. In this study, we conducted a comprehensive investigation on the influence of INBs on boundary conditions for both smooth and rough substrates using molecular dynamics simulations. We analyzed the impact of INB protrusion angle, coverage percentage, quantity, and fluidity on the slip length. Our results showed that INBs always increase the slip length on a smooth substrate, with a linear increase in slip length observed with increasing surface coverage. On a rough substrate, we found that the protrusion angle, quantity, and fluidity of INBs play a crucial role in determining the slip length. Smaller protrusion angles and fewer quantities of INBs were found to be more favorable for enhancing the slip length when the INB coverage is fixed, while the correlation between boundary slip and INB quantity depended on the wetting state of the substrate when the size of the INBs was fixed with a low protrusion angle. Additionally, we revealed that the fluidity of gas molecules inside the INBs dominated the enhancement of slip length by INBs. Overall, our findings are expected to provide valuable insight into drag reduction based on INBs.

Coal floatability evaluation is of vital importance in the prediction of flotation results and the design of a flotation flowsheet. In this work, a new experimental approach based on bubble–particle attachment kinetics (BPAK) and bubble–particle detachment kinetics (BPDK) were proposed to evaluate the floatability of coal particles. During attachment and detachment processes, a variation of coating angles θ(t) for different density coal particles were measured and fitted to a first-order model. Modified attachment rate constant ka* and modified detachment rate constant kd* were used as yardsticks of floatability. For comparison, flotation kinetics, induction time, and contact angle measurements were also conducted. A consistent sequence of floatability was obtained as: −1.4 > 1.4–1.6 > +1.6 g/cm3. The modified flotation rate constant k* obtained in flotation kinetics was used as a yardstick to assess the accuracy of floatability evaluation methods. By individually fitting k* to parameters obtained in other tests, a simple and close linear relationship between k* and modified attachment rate constant ka* was established, rather than 1/kd* in BPDK tests, induction time tind, or (1 – cosα) in contact angle measurements. Consequently, ka* is thought to be a better criterion as k* could be quantitatively predicted by BPAK tests. Throughout this work, BPAK is an effective method to evaluate coal floatability.

Bubble-particle attachment and detachment are fundamental subprocesses of flotation, a deep understanding of which is essential for predicting flotation kinetics. This paper focuses on the kinetics of bubble-particle attachment and detachment at a single-bubble scale. Kinetics experiments of attachment, detachment, and flotation using coal samples with low-density fraction (LDF), middle-density fraction (MDF), and high-density fraction (HDF) were conducted. Models of bubble-particle attachment and detachment kinetics were proposed by an analogy with flotation kinetics equations. With an increase in coal density, the attachment rate constant decreased, while the detachment rate constant increased, which was consistent with the decrease in floatability of coal. In addition, the experimental data of the attachment and detachment kinetics was compared with flotation kinetics (multi-bubble scale). The optimal fitted models for LDF and MDF were the classical first-order models of attachment/detachment/flotation kinetics. These consistencies indicated the floatability of coal could be characterized by the attachment and detachment kinetics at a single-bubble scale. This was not the case for HDF (gangue minerals in essence), since its optimal models of the attachment/detachment kinetics were the third-order models, while for flotation kinetics was the first-order model with rectangular distribution. This contradiction indicated the flotation of the high-density particles might be significantly affected by the bubble concentration.

Information on the effects of halophyte communities on soil organic carbon (SOC) is useful for sequestrating C in arid regions. In this study, we identified four typical natural halophyte communities in the Manasi River Basin in Xinjiang Province, Northeast China, namely, Karelinia caspia (Pall.) Less., Bassia dasyphylla (Fisch. et C. A. Mey.) Kuntze, Haloxylon ammodendron (C. A. Mey.) Bunge, and Tamarix ramosissima Lour. We compared soil aggregation and aggregated-associated SOC under these communities. The aggregate fraction of 0.053–0.25 mm accounted for 47%–75% of the total soil mass, significantly more than the > 0.25 and 0.25 mm aggregates (13.3%–43.8%) and T. ramosissima community having more 0.25 mm fraction, followed by the T. ramosissima (4.9 g kg−1) > K. caspia (4.2 g kg−1) > B. dasyphylla (3.4 g kg−1). The H. ammodendron community had the highest total SOC and aggregate-associated SOC, which was primarily because aggregate-associated SOC content at the 0–10 and 10–20 cm depths under this community were higher than those under other plant communities. The H. ammodendron community could be beneficial for increasing SOC in saline soils in the arid region.

Low-rank coal (LRC) contains large amounts of harmful impurities that must be processed before utilization. Flotation is an effective means for separating fine particles, which can be influenced by air solubility in water. In this work, deaerated water (DW), ordinary water (OW), and pressurized water (PW) were prepared to research the underlying mechanism of the effect of air solubility on the flotation performance of LRC. The results show that PW dissolves the greatest amount of air in the three kinds of water (DW, OW, and PW). The flotation performance of LRC in different water types is directly proportional to air solubility in aqueous solutions. In addition, the induction time of LRC in PW (600 ms) is significantly shorter than those in OW (1200 ms) and DW (4000 ms). Atomic force microscopy (AFM) studies reveal that typical interfacial nanobubbles (NBs) only form on a highly oriented pyrolytic graphite (HOPG) surface in PW due to the supersaturated air in water. Furthermore, the interaction between LRC particles and HOPG in PW is significantly stronger than those in both OW and DW, which is attributed to the capillary force of rgw nanobubble bridge formed between particles. The hydrophobic interaction enhanced by NBs is critically important for the attachment of LRC particles to macrobubbles in flotation. Overall, air solubility in water has a great effect on LRC flotation performance, and PW flotation technology can be extended to LRC purification.

In-memory key-value store (KVS) has become crucial for many large-scale Internet services providers to build highperformance data centers. While most of the state-of-the-art KVS systems are optimized for read-intensive applications, a wide range of applications have been proven to be insert-intensive or scan-intensive, which scale poorly with the current implementations. With the availability of FPGA-based smart NICs in data centers, hardware-aided and hardware-based KVS systems are gaining their popularity. In this paper, we present HeteroKV, a scalable line-rate KVS on heterogeneous CPU-FPGA platforms, aiming to provide high throughput in read-, insert- and scan-intensive scenarios. To achieve this, HeteroKV leverages a heterogeneous data structure consisting of a b+ tree, whose leaf nodes are cache-aware partitioned hash tables. Experiments demonstrate HeteroKV's high performance in all scenarios. Specifically, a single node HeteroKV is able to achieve 430M, 315M and 15M key-value operations per second in read-, insert- and scan-intensive scenarios respectively, which are more than 1.5x, 1.4x and 5x higher than state-of-the-art implementations.

It is well-known that ultra-fine particles, especially those with oxidized surface, are difficult to float using conventional methods. Flotation of oxidized ultra-fine particles has been a serious problem which should be well solved as the demand for energy is increasing. In this investigation, the flotation behaviors of fresh and oxidized fine coal (

The objective of this study was to evaluate bacterial community structure and diversity in soil aggregate fractions when salinized farmland was reclaimed after >27 years of abandonment and then farmed again for 1, 5, 10, and 15 years. Illumina MiSeq high-throughput sequencing was performed to characterize the soil bacterial communities in 5 aggregate size classes in each treatment. The results indicated that reclamation significantly increased macro-aggregation (>0.25 mm), as well as soil organic C, available N, and available P. The 10-year field had the largest proportion (93.9%) of soil in the macro-aggregate size classes (i.e., >0.25 mm) and the highest soil electrical conductivity. The 5 most dominant phyla in the soil samples were Proteobacteria, Actinobacteria, Gemmatimonadetes, Acidobacteria, and Bacteroidetes. The phylogenetic diversity, Chao1, and Shannon indices increased after the abandoned land was reclaimed for farming, reaching maximums in the 15-year field. Among aggregate size classes, the 1–0.25 mm aggregates generally had the highest phylogenetic diversity, Chao1, and Shannon indices. Soil organic C and soil electrical conductivity were the main environmental factors affecting the soil bacterial communities. The composition and structure of the bacterial communities also varied significantly depending on soil aggregate size and time since reclamation.

Traditional froth flotation is the primary method for the separation and upgrading of fine mineral particles. However, it is still difficult for micro-fine and low-quality minerals to effectively separate. It is generally believed that bubble miniaturization is of great significance to improve flotation efficiency. Due to their unique physical and chemical properties, the application of nanobubbles (NBs) in ore flotation and other fields has been widely investigated as an important means to solve the problems of fine particle separation. Therefore, a fundamental understanding of the effect of NBs on flotation is a prerequisite to adapt it for the treatment of fine and low-quality minerals for separation. In this paper, recent advances in the field of nanobubble (NB) formation, preparation and stability are reviewed. In particular, we highlight the latest progress in the role of NBs on particles flotation and focus in particular on the particle-particle and particle-bubble interaction. A discussion of the current knowledge gap and future directions is provided.

The soil microbial biomass carbon (MBC) is considered as a sensitive index of soil carbon ecosystem. The distribution of aggregate-associated MBC determines the capacity of the soil to store soil organic carbon (SOC). We compared soil aggregate-associated SOC and aggregate-associated MBC under four halophyte communities: Karelinia caspia (Pall.) Less. (Abbr. K. caspia), Bassia dasyphylla (Fisch. et C. A. Mey.) Kuntze. (Abbr. B. dasyphylla), Haloxylon ammodendron (C. A. Mey.) Bunge. (Abbr. H. ammodendron), and Tamarix ramosissima Lour (Abbr. T. ramosissima) on an alluvial fan in the Manasi River Basin, Xinjiang, China. The specific objectives of the study were to determine which aggregate size fraction was the most important for MBC and SOC retention in these soils of four halophyte communities. The results showed that the 0.053–0.25 mm fraction contained 47 to 75 % of the total soil mass. The amount of soil in the 0.053–0.25 mm fraction was significantly greater than that in the >0.25 and the 0.25 and the 0.25 and the 0.25 mm fraction than the other two aggregate fractions, and there were no significant differences in 0.25–0.053 or 0.25 mm fraction (P 0.25 mm fraction. Overall, the H. ammodendron community had the higher aggregate-associated SOC and aggregate-associated MBC, but the microbial entropy was low. This suggested that among the four halophyte communities in this study, the H. ammodendron community could be beneficial for soil carbon storage in arid regions.

SUMMARYA field experiment was conducted to quantify changes in soil aggregation and aggregate-associated soil organic carbon (SOC) concentration 1, 3, 5 and 10 years after abandoned, salinized land in the Manasi River Basin was reclaimed for cotton (Gossypium hirsutum L.). Results showed that reclamation significantly increased SOC concentrations and SOC stocks. Specifically, 10 years of cotton production increased SOC concentrations by 45% in the 0–60 cm depth and SOC stocks by 35%. The SOC concentrations and stocks decreased as soil depth increased. Reclamation time, season and soil depth had significant interaction effects on SOC. The SOC concentrations were significantly and positively correlated with available soil nitrogen and available soil phosphorus. Compared with abandoned farmland, macro-aggregate-associated (>250 µm) SOC concentrations in the 0–60 cm depth increased by 47% after 5 years of cotton production and by 53% after 10 years of cotton production. The contribution of macro-aggregate-associated SOC to total SOC in the 0–60 cm depth increased by 87% after 5 years of cotton production and by 69% after 10 years of cotton production. The findings indicate that soil aggregates were more stable after abandoned, salinized farmland was reclaimed for cotton production. Furthermore, cotton production can increase SOC concentrations and sequester C in this arid area.

Reclamation of abandoned farmland is crucial to a sustainable agriculture in arid regions. This study aims to evaluate the impact of different reclamation treatments on abandoned salinized farmland. We investigated four artificial reclamation treatments, continuous cotton (CC), continuous alfalfa (CA), tree-wheat intercropping (TW) and trees (TS), which were conducted in 2011–2012 in the Manasi River Basin of Xinjiang Province, China. Soil nutrient, microorganism and enzyme activity were examined in comparison with natural succession (CK) in an integrated analysis on soil fertility improvement and soil salinization control with these reclamations. Results indicate that the four artificial reclamation treatments are more effective approaches than natural restoration to reclaim abandoned farmland. TW and CA significantly increased soil nutrient content compared to CK. CC reduced soil salinity to the lowest level among all treatments. TW significantly enhanced soil enzyme activity. All four artificial reclamations increased soil microbial populations and soil microbial biomass carbon. TW and CA had the greatest overall optimal effects among the four treatments in terms of the ecological outcomes. If both economic benefits and ecological effects are considered, TW would be the best reclamation mode. The findings from this study will assist in selecting a feasible method for reclamation of abandoned farmland for sustainable agriculture in arid regions.

In recent years, Xinjiang Oasis has faced a major challenge of increasing risk of secondary salinization caused by drip irrigation under plastic mulch. Predicting the salt balance is therefore essential for understanding how to sustain the use of salinized land in this arid area. This research validated the SWAGMAN (Salt, Water And Groundwater MANagement) Destiny model to simulate and forecast the movement of salt in different soil textures based on field experiments. The results were verified with extensive field work in Shihutan, Xinjiang, China. They show that soil salinity decreases in the upper layers and increases in the bottom layers of the investigated soil profile. The desalinization rate in sand, which shows an overall steady trend throughout the soil profile, is generally higher than that in loam and clay. The depth of 60cm is critical for loam and clay; soil salinity decreases above it but increases below it. Model sensitivity analysis reveals the variation of soil salinity is independent of the initial electrical conductivity setting of SWAGMAN Destiny simulations. This study indicates that numerical modelling is a useful approach for efficiently estimating the salt balance under drip irrigation. The result provides a scientific basis for making adaptive strategies to manage salinised farmlands in arid zones.

During the coal flotation process, high ash coal fines are carried into foam, although process optimization can reduce ash content. This paper suggests an alternative method for coal flotation which has a significant effect on quality, coal production processes and plant design.