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This study reports the synthesis of a novel adsorbent, hereinafter named almond shell-based activated carbon (ASAC), from waste almond shells (AS) via exposure to microwave radiation and the use of ZnCl2 as a chemical activator. Synthetic conditions were further elaborated using the response surface methodology to optimize the adsorption capacity of ASAC for methylene blue (MB) dye. The optimized ASAC preparation conditions were found to be as follows: a mass (ZnCl2/AS) ratio of 3:1 (w/w) and microwave heating time period of 15 min at 900 W. A maximum ASAC yield of 39.67% and a MB adsorption capacity of 314.20 mg/g were obtained. ASAC was also characterized by N2 adsorption-desorption measurement, scanning electron microscopy (SEM), Fourier-transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), and point of zero charge measurement. Optimized ASAC had a Brunauer-Emmett-Teller surface area of 839.60 m2/g and a total volume of 0.406 cm3/g. FTIR and XPS analysis exhibited a decline in oxygen-containing groups of ASAC as compared with AS. The adsorption behavior of ASAC for MB was fitted well to the pseudo-second-order model and the Langmuir isotherm model. These findings support the ease of preparation and cost effectiveness that make ASAC promising for use in environmental remediation.

By introducing heterogeneous lamella-structure, we obtained a superior strength-ductility synergy in Mg-alloy associated with excellent strain-hardening ability, i.e. yield strength of ∼251 MPa, tensile strength of ∼393 MPa and elongation of ∼23%. By using advanced characterization techniques, we showed that strengthening was mainly caused by the non-uniform distribution of hetero-deformation induced (HDI) stress associated with grain-boundary disclinations, which are mediated by heterogeneous multi-grain interactions. Induced by grain-boundary disclinations and intergranular slip transfers, a variety of abnormal deformation modes have been activated，which contributed significantly to enhanced ductility. This work suggests a new avenue to evade strength-ductility trade-off dilemma in Mg-alloys. The heterogeneous lamella-structure leads to sustained strain-hardenability in Mg-alloy with unique accommodating deformation modes (extensive abnormal slips and feather-shaped twins), induced by grain-boundary disclinations and intergranular slip transfers. [ABSTRACT FROM AUTHOR]

Data deduplication has been widely employed in flash-based storage as an effective technique for enhancing reliability and cost efficiency. However, the read/write interference problem of flash storage, where on-going write requests prevent read requests from accessing available data and significantly increase read latency, remains a critical concern with the rapid evolutions of flash chips from SLC through MLC to TLC and on to QLC, with PLC on the horizon, especially under workloads with a mixture of read and write requests. To significantly improve the read performance in face of read/write interference, which is often more critical than the write performance, we propose an enhanced Hot Read Data Replication scheme for deduplication-based flash storage, called DedupHR, to alleviate the read/write interference problem. DedupHR exploits the content locality in the deduplication-based flash storage and outsources the data blocks with high reference count to a surrogate space such as a dedicated spare flash chip or an over-provisioned space in an SSD. By servicing some conflicted read requests on the surrogate flash space, DedupHR can significantly alleviate, if not entirely eliminate, the contention between the read requests and the on-going write requests. The evaluation results show that DedupHR significantly improves the state-of-the-art schemes in terms of the system performance and cost efficiency. Consequently, the tail-latency of the deduplication-based flash storage is also reduced. [ABSTRACT FROM AUTHOR]

Fluoride (F) pollution is a serious environmental problem in some areas of China, but it has yet to be reported in a soil–water–plant system in Shihezi, Xinjiang. This study was undertaken to investigate the distribution and migration rule of F in soil, water, and plants, and to evaluate F pollution of soil. Results showed that the average concentration of total F (T-F) in the topsoil in the northwest, north, and southeast of Shihezi was higher than the national average T-F (478 mg/kg), while it was lower in southwest. The highest T-F contents of the soil profile were detected in the depth of 20 cm. The F content in groundwater in the northwest region was higher than the GB/T 14848–93 (1.0 mg/L), whereas the F contents in other water samples were within the standard. The F contents (1.75−2.81 mg/kg) in plant leaves were higher than the food limits (1.0 mg/kg). The obtained comprehensive pollution index of the soil was 1.86, which means a mild concentration of F in Shihezi. This research has reference value for the study of F pollution and comprehensive control in the northwest oasis with the typical arid and saline conditions. [ABSTRACT FROM PUBLISHER]