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Capillary barrier effects (CBEs) have been applied in capillary barrier systems as effective means of protecting underground regions from wetting. However, the microscale behavior of CBEs and related influencing factors are not well understood. This study utilized microfluidics to investigate effects of flow rate and pore size variability on CBEs at the microscale. Imbibition processes of water displacing air were imposed on three water-wet microfluidic chips with different degrees of pore size variability and injection rates. The obtained results demonstrated that the increasing injection rate changed water invasion pattern from finger growth to compact displacement. The CBEs could increase [S.sub.wf] (water saturation of fine sections at the onset of breakthrough) by up to 44%. The increase in [S.sub.wf] became smaller at a higher injection rate but was insensitive to the pore size variability within the investigation range. This study also elaborated the specific effect of inertia on pore body invasions under different pore characteristics. Among the materials with close average pore size, those with more uniform pore sizes are recommended for the construction of capillary barrier systems. For capillary barrier systems with robust CBEs, increasing the thicknesses of coarse layers has insignificant effect on reducing deep percolation. Key words: microfluidics, capillary barrier effect, favorable imbibition, flow rate, pore size variability, 1. Introduction Capillary barrier effects (CBEs) can be formed at the interfaces between fine- and coarse-grained soils in unsaturated conditions. Briefly, owing to their smaller pore sizes, the fine-grained soils [...]

The large-sized Tarangaole uranium deposit and its neighboring Daying and Nalinggou deposits, located in the northeastern margin of the Ordos Basin, constitutes a major uranium resource base in northern China. In order to further clarify the sedimentary material source, uranium source and regional sediment–tectonic setting of the uranium-fed clastic rocks (i.e., Zhiluo Formation(J2z)) in the district, this paper carried out whole-rock geochemistry, heavy minerals composition and in situ U-Pb dating of detrital zircons for sandstones from the lower section of the Zhiluo Formation. The results have shown that the average chemical differentiation index (CIA) for the host rocks is 73.16 and the chemical weathering degree is moderate. Heavy minerals are mainly composed of ilmenite, garnet, chlorpyrite, zircon, pyrite, apatite, hematite, etc. The U-Pb dating of detrital zircon generally indicates three age peaks, i.e., 260~Ma, 1850~Ma and 2450~Ma, respectively. In conclusion, the source rocks may have been formed at active continental margins, e.g., in a continental margin arc environment. The sedimentary materials mainly come from khondalite series, TTGs, granulite, and mafic–ultramafic intrusive rocks distributed among the Daqing–Ula Mountains and adjacent areas, etc. The Late Paleozoic U-rich intermediate and acidic magmatic rocks spreading over the eastern part of the Ula–Daqing and Wolf mountains have provided the main uranium sources for the formation of major U deposits in the northern Ordos Basin. [ABSTRACT FROM AUTHOR]

A 30 m long x 20 m wide capillary barrier cover (CBC) test site was constructed at the Jiangcungou landfill in Xi'an, China. The cover consisted of a compacted loess layer with a thickness of 0.9 m underlain by a gravel layer. After the cover surface was kept bare and exposed to natural climate conditions for nearly 5 months, one artificial rainfall event was implemented at the site. Vegetation was established at the test site after the first rainfall event. Four months later, a second artificial rainfall event was applied to the surface of the vegetated site. The pore-water pressures (PWPs) and volumetric water contents (VWCs) of the cover were monitored using jet-filled tensiometers and time-domain reflectometry moisture probes, respectively. Surface runoff and percolation were measured using field collection devices. The field measurements demonstrated a more rapid response of PWPs to the rainfall compared to the response of the VWCs. Percolation was observed when the PWPs near the interface reached the water-entry value of the gravel at local points. At that moment, the measured VWC near the interface was less than the VWC according to the water-entry value. The observation indicated that preferential flows took place in the compacted loess during the rainfall. As a result, the maximum water storage capacity was not reached at the onset of percolation. When percolation ceased, the average PWP near the interface decreased below the water-entry value, while the VWC near the interface was higher than that at the onset of percolation. Water storage at the completion of percolation was approximately 5% greater than that at the onset of percolation. Compared with the monolithic loess cover, the loess-gravel CBC increased the available water storage capacity by 41% at the completion of percolation. Vegetation had an insignificant influence on water storage capacity. Key words: loess-gravel capillary barrier cover (CBC), artificial rainfall, hydraulic responses, capillary barrier, water storage capacity. Un site de test de 30 m de longueur x 20 m pour une barriere capillaire large (CBC) a ete construit au site d'enfouissement de Jiangcungou a Xi'an, Chine. Le couvercle se composait d'une couche de lress compacte avec une epaisseur de 0,9 m reposant sur une couche de gravier. Apres que la surface de la couverture a ete gardee nue et exposee aux conditions climatiques naturelles pendant pres de 5 mois, un evenement de pluie artificielle a ete mis en place sur le site. La vegetation a ete creee sur le site de test apres la premiere epreuve de pluie. Quatre mois plus tard, un second evenement de pluie artificielle a ete applique a la surface du site vegetalisee. Les pressions d'eau interstitielle (PGR) et la teneur en eau volumetrique (VWCs) de la couverture ont ete mesurees a l'aide de tensiometres remplis de jet et sondes de l'humidite a reflectometrie, respectivement. L'infiltration et le ruissellement de surface ont ete mesures a l'aide de dispositifs de collecte de champ. Les mesures sur le terrain ont demontre une reponse plus rapide dans les PWP pour les precipitations par rapport a la reponse des VWC. La percolation a ete observee lorsque la PGR pres l'interface atteint la valeur d'entree d'eau du gravier aux points locaux. Au meme moment, les VWC mesurees pres de l'interface ont ete inferieures au VWC selon la valeur d'entree d'eau. L'observation a indique que les flux preferentiels ont eu lieu dans le lress compacte pendant les precipitations. Ainsi, la capacite de stockage maximale de l'eau n'etait pas atteinte au debut de la percolation. Lors de la cessation de percolation, le PWP moyen pres de l'interface a diminue au-dessous de la valeur d'entree de l'eau, tandis que le VWC pres de l'interface etait plus eleve qu'au debut de la percolation. Le stockage d'eau a la fin de la percolation a ete approximativement 5 % superieure a celle au debut de la percolation. Par rapport a la couverture de lress monolithique, le lress/gravier CBC a augmente la capacite de stockage d'eau disponible de 41 % a la fin de la percolation. La vegetation a eu une influence negligeable sur la capacite de stockage d'eau. [Traduit par la Redaction] Mots-cles: lress-gravier barriere capillaire large (CBC), pluies artificielles, reponses hydrauliques, barriere capillaire, capacite de stockage d'eau., Introduction As one of the important components of solid waste disposal, final cover systems minimize percolation into the underlying waste and limit emission of landfill gas. In recent years, there [...]

The capillary barrier effect (CBE) is employed in a large number of geotechnical applications to decrease deep percolation or increase slope stability. However, the micro-scale behaviour of CBE is rarely investigated, and thus hampers the scientific design of capillary barrier systems. This study uses microfluidics to explore the micro-scale behaviour of CBE. Capillarity-driven water flow processes from fine to coarse porous media with different pore topologies and sizes were performed and analysed. The experimental results demonstrate that the basic physics of CBE is the preferential water movement into the fine porous media due to the larger capillarity. The effects of CBE on water flow processes can be identified as delaying the occurrence of breakthrough into the coarse porous media and increasing the water storage of the fine porous media. The CBE can impede the increase of the normalised length and decrease the normalised width of the water front, suggesting that the two normalised parameters are potential indicators to assess the performance of CBE at the micro scale. CBE can be formed in square and honeycomb networks with the ratio of coarse to fine pore throat width larger than 2·0 when gravity is neglected, and its performance can be affected by pore topology and size. [ABSTRACT FROM AUTHOR]

What Is Known and Objective. The primary cause of trabeculectomy failure in glaucoma surgery is the imperfect formation of the filter bubble, which blocks the filtration effect. This systematic review and meta-analysis aimed to compare the effects and safety of mitomycin C (MMC) or no antimetabolite in trabeculectomies cases that require needling revision. Methods. We searched PubMed, Cochrane, and EMBASE to identify randomized trials published between the time the databases were built and May 31, 2022. To compare the effectiveness and safety of mitomycin with or without mitomycin in trabeculectomy, intraocular pressure (IOP), the surgical failure rate, and functional follicle formation were used as efficacy indicators, and the occurrence of postoperative complications was used as a safety indicator. Meta-analyses were performed for comparisons. Results and Discussion. After trabeculectomy, MMC was significantly better than a placebo at lowering postoperative IOP (MD = −11.31 mmHg, 95% CI −19.73 to −2.88 mmHg). MMC outperformed the control group in terms of filtering blebs formation (relative risk (RR) = 1.18, 95% CI: 1.09 to 1.27). The surgical failure rate was significantly lower with MMC compared to placebo (RR = 0.35, 95% CI: 0.22 to 0.58). No significant difference was observed between MMC and placebo in terms of hypotony, anterior chamber bleeding, filter bubble leakage, and endophthalmitis, apart from the shallow anterior chamber (RR: 1.51, 95% CI: 1.02 to 2.25). What Is New and Conclusion. The use of MMC in glaucoma trabeculectomy can increase the success rate of the procedure and provide significant patient benefits. However, it is important to be extremely careful and aware of complications such as shallow anterior chambers. [ABSTRACT FROM AUTHOR]

This study aims to explore the factors influencing the success rate of the microdissection testicular sperm extraction (Micro-TESE) in patients with nonobstructive azoospermia (NOA) and cryptorchidism. Clinical data of 162 patients with cryptorchidism who underwent Micro-TESE due to infertility from December 2015 to May 2020 in the First Affiliated Hospital of Nanjing Medical University were analyzed retrospectively. In the univariate analysis, significant differences in the age of patient at the time of orchidopexy (median [interquartile range, IQR]: 7.0 [4.0–11.0] years vs 11.5 [9.0–14.5] years, P < 0.001), interval between orchidopexy and Micro-TESE (mean ± standard deviation: 17.5 ± 5.0 years vs 14.4 ± 4.4 years, P < 0.001), severity of cryptorchidism (unilateral [62.8%] vs bilateral [31.6%], P < 0.001; location of cryptorchidism, intra-abdominal [27.3%] vs inguinal [44.8%] vs suprascrotal [66.7%], P < 0.001), volume of the dominant testis (median [IQR]: 17.00 [15.00–19.00] ml vs 14.50 [11.75–16.25] ml, P < 0.001), and levels of follicle-stimulating hormone (FSH; P = 0.004) and testosterone (P = 0.006) were observed between the successful and failed sperm extraction groups. After conducting the multivariate analysis, four of these factors, including unilateral/bilateral cryptorchidism (P < 0.001), location of cryptorchidism (P = 0.032), age of orchidopexy (P < 0.001), and dominant testicular volume, were adopted in the clinical prediction model to evaluate preoperatively the success rate of Micro-TESE for patients with NOA and cryptorchidism. The likelihood of successful sperm retrieval by Micro-TESE in men with NOA and cryptorchidism increased in patients with mild forms of cryptorchidism. [ABSTRACT FROM AUTHOR]