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This paper refers to a survey conducted in Zhengzhou section of the Yellow River for the purpose of investigating heavy metal pollution characteristics and of exploring the pollution sources. Monitoring was thereby carried on August 29-31, 2022 along the riparian zone collecting samples of the river sediments and analyzing the concentrations of nine kinds of heavy metal, including Cd, Pb, Cu, Zn, As, Hg, Cr, Ni and Mn. Then the Tessier five-step sequential extraction method was used for the morphological analysis of the heavy metals; the ground accumulation index (Igeo) was used to evaluate heavy-metal pollution degree, with Nemero pollution index being applied to the comprehensive assessment of the pollution situation; and the principal component analysis (PCA) and absolute factor analysis-multiple linear regression analysis model (APCS-MLR) were used to analyze the source of the pollutants. Consequently, the survey showed that both of the mean concentrations of Pb and Cd in the sediments of the riverine zone of Zhengzhou section of the Yellow River exceeded the soil background value of heavy-metal in Henan Province. Results of the speciation analysis showed that the environmental activities of Mn, Cd, Pb and Hg were relatively high; the evaluation of geo-accumulation index (Igeo) indicated that Cd had resulted in slight to moderate pollution in the sediments of the River; and the evaluation results of the Nemero pollution index showed that all the above-mentioned heavy-metal elements were on the safety level. Result of the source apportionment suggested that tannery industry, agricultural activities and automobile parts production, as well as the natural source were the major heavy-metal pollution sources in the riparian zone of Zhengzhou section of the Yellow River. [ABSTRACT FROM AUTHOR]

In this paper, an improved axisymmetric interfacial lattice Boltzmann flux solver abandoning the previous predictor-corrector scheme is proposed. Unlike the previous model starting from the two-dimensional standard lattice Boltzmann method (LBM), the present method is developed using the axisymmetric LBM, which directly incorporates the axisymmetric effects into the distribution functions. As a result, the proposed solver does not need the corrector step involving complicated space derivatives. It makes this method simpler and more computationally efficient. In the present solver, the resultant governing equation is globally resolved by the finite volume method, while the fluxes are reconstructed by local application of the axisymmetric LBM. Therefore, the inconsistency between the local reconstruction and the global governing equation can be eliminated because the global equation can be strictly derived from the axisymmetric LBM, which holds stronger physical basis than the previous method. Numerical experiments about the interface capturing and the multiphase flows are conducted to test the proposed model. Results show that the present method is superior to the fractional step solver in terms of the accuracy, stability, and computational efficiency. In addition, this solver has the capacity of simulating large-density-ratio and complex interfacial change. [ABSTRACT FROM AUTHOR]

Microbial necromass carbon (MNC) is a crucial source for stable soil carbon pool, and understanding its response to carbon inputs from both aboveground (litter) and belowground (roots) in subtropical forest soils is essential for assessing soil carbon stocks in global ecosystems. In a Castanopsis carlesii plantation at the Sanming Forest Ecosystem National Observation and Research Station in Fujian Province, we conducted an experiment with five treatments, including root removal (NR), aboveground litter removal (NL), no litter input (removals of both aboveground litter and roots, NI), double aboveground litter addition (DL), and control (CK). After seven years, we collected soil samples in the 0-10 cm soil layer to examine changes in MNC content and its contribution to soil organic carbon (SOC). Results showed that NR treatment reduced MNC, bacterial necromass carbon (BNC), and fungal necromass carbon (FNC) by 15.9%, 20.2%, and 14.5%, respectively, while other treatments did not induce significant changes. The NR, NL, NI, and DL treatments did not affect the contributions of BNC, FNC, and MNC to SOC. Correlation and path analyses revealed that litter and root carbon input treatments could alter the MNC content directly or indirectly through changing soil available substrates and microbial community structure. Our results suggested that roots exert a stronger influence on the maintenance of MNC than aboveground carbon source in the mid-subtropical plantations. [ABSTRACT FROM AUTHOR]

This study focuses on legislative bans imposed on short‐term rentals (STRs) and evaluates their effects on long‐term rentals in Irvine, CA. We find that contract rental prices in the long‐term rental market decrease by 3.0% within approximately 2 years after the enforcement of STR ordinance. The results are primarily driven by the supply side for long‐term rentals. The decline in rents is more pronounced: (1) for long‐term rental units that have similar property characteristics as those listed through Airbnb and (2) for those located in geographic areas with greater Airbnb exposure before the ban was enforced. [ABSTRACT FROM AUTHOR]

In view of problems of poor accuracy and dependence on source coordinates of existing underground positioning algorithm, an underground positioning method based on GMapping algorithm and fingerprint map construction was proposed. The signal characteristics of unknown position is matched with signal distribution map, and the optimal positioning coordinates is selected, thereby improving accuracy of the underground positioning; by combining with GMapping algorithm, problem of high maintenance cost of fingerprint map construction process is avoided, and searching and matching efficiency of the algorithm is optimized. Actual test results show that the average positioning error of the proposed method is 57.7 cm, which can meet requirements of underground positioning.

In view of problems of low illumination, a lot of dust and complex electromagnetic environment in coal mine underground, and images' quality captured by underground monitoring equipment would be reduced in transferring process caused by underground noises, an underground monitoring image sharpening device based on embedded system was designed. The device uses wavelet threshold algorithm and DSP embedded system, and it can effectively restrain noise, meanwhile keep details characteristics and peak point of original images, which greatly enhances monitoring image clarity.

We examine the iBuyers' business model and their impact on housing markets. We find that iBuyers tend to enter neighborhoods that have more easily priced and homogeneous homes, as price discovery is simpler and more consistent with their pricing algorithm in those areas. iBuyers purchase homes at lower prices than individual owner‐occupiers, and this acquisition discount reflects the benefits iBuyers offer to motivated sellers rather than distressed home purchases or unobserved lower‐quality housing characteristics. Last, a greater presence of iBuyers results in a higher volume of local housing transactions and encourages more home sellers to sell without listing. [ABSTRACT FROM AUTHOR]

Recently, a one-step simplified lattice Boltzmann method abandoning the original predictor–corrector scheme has been proposed for single-phase flows. In this method, the information of non-equilibrium distribution function (DF) is implicitly included in the difference of two equilibrium DFs at two different locations and time levels. Due to this treatment, the one-step method faces challenges such as extra virtual memory cost and additional boundary treatments. To overcome these drawbacks, a novel one-step simplified lattice Boltzmann method (NOSLBM) is developed by directly constructing the non-equilibrium DF with macroscopic variables. The NOSLBM preserves the merits of high computational efficiency and simple code programming in the original one-step method. Moreover, the present method is extended to multiphase flows. One NOSLBM for the solution of the Cahn–Hilliard equation is employed to capture the interface. Another one is adopted to solve the Navier–Stokes equations for the hydrodynamic fields. Numerical tests about interface capturing and single-phase flows indicate that the present method has a better performance on computational efficiency than that of the simplified multiphase lattice Boltzmann method (SMLBM), in which the predictor–corrector scheme is applied. Numerical tests about binary fluids with large density ratio imply the great accuracy and numerical stability of the present method. [ABSTRACT FROM AUTHOR]