DataSheet_1_A statistical assessment of the density of Antarctic krill based on “chaotic” acoustic data collected by a commercial fishing vessel.docx

With the development of acoustic data processing technology, it is possible to make full use of the “chaotic” acoustic data obtained by fishing vessels. The purpose of this study is to explore a feasible statistical approach to assess the Antarctic krill density rationally and scientifically based on the acoustic data collected during routine fishing operations. The acoustic data used in this work were collected from the surveys conducted by the Chinese krill fishing vessel F/V Fu Rong Hai since the 2015/16 fishing season in the Bransfield Strait. We first processed acoustic data into small units of 0.1 nm, then selected the location of the central fishing ground for grid processing. Because of many zero and low values, we established a Regional Gridding and Extended Delta-distribution (RGED) model to evaluate the acoustic density of the krill. We defined the selection coefficient of grid size by using the coefficient of variation (CV) of the mean density and the weight of the effective covered area of the grids. Through the comparison of selection indexes, cells of 5′S × 10′W were selected as a computational grid and applied to the hotspot in the Bransfield Strait. Acoustic data reveal the distribution of krill density to be spatially heterogeneous. The CV of the mean density for 4 months converges at ~15% for cells of 5′S × 10′W. Simulations estimate krill resource densities in February to be ~1990 m2 nm−2 and to increase to ~8760 m2 nm−2 in May (4.4 times higher). We deem the RGED model to be useful to explore dynamic changes in krill resources in the hotspot. It is not only of great significance for guiding krill fishery, but it also provides krill density data for studying the formation mechanism of the resource hotspots.</p

Superior Performance of Copper Based MOF and Aminated Graphite Oxide Composites as CO₂ Adsorbents at Room Temperature

New composites Cu-BTC MOF and graphite oxide modified with urea (GO-U) are developed and tested as CO₂ adsorbents at room temperature. The composite containing GO-U with the highest nitrogen content exhibits an excellent CO₂ uptake (4.23 mmol/g) at dynamic conditions. The incorporation of GO-U into MOF changes the chemistry and microstructure of the parent MOF and results in synergistic features beneficial for CO₂ retention on the surface. To identify these features the initial and exhausted materials were extensively characterized from the points of view of their porosity and chemistry. Although the adsorption forces are relatively strong, the results indicate that CO₂ is mainly physisorbed on the composites at dry dynamic conditions at ambient temperature and pressure. The primary adsorption sites include small micropores specific for the composites, open Cu sites, and cage window sites

Cu-BTC/Aminated Graphite Oxide Composites As High-Efficiency CO₂ Capture Media

CO₂ adsorption isotherms on Cu-BTC/aminated graphite oxide composites were measured in the pressure range up to 1.5 MPa at three different temperatures close to ambient. Adsorption capacity, isosteric heat of adsorption, and regenerability were investigated. They are considered as significant factors determining the practical application of materials for CO₂ capture. The results indicate a significant improvement in the performance of the composites as CO₂ adsorbents in comparison with the parent Cu-BTC MOF. Among all samples analyzed, the composite of Cu-BTC and modified graphite oxide with the highest N content (MOF/GO-U3) is the best performing sample. On its surface 13.41 mmol/g CO₂ was adsorbed at room temperature and 1.5 MPa. A high selectivity for CO₂ adsorption over that of CH₄ was found. The selectivities for CO₂ adsorption over N₂ are governed by the properties of the MOF phase. A relatively low heat of CO₂ adsorption and the high degree of surface homogeneity cause that the composites can be fully regenerated and used in multicycle adsorption with the minimum energy demand

A Rational Design for Enhanced Catalytic Activity and Durability: Strongly Coupled N‑Doped CrO_<i>x</i>/Ce_0.2Zr_0.8O₂ Nanoparticle Composites

As a classic catalyst for NO oxidation, CrO_<i>x</i>/Ce_0.2Zr_0.8O₂ has been widely researched to improve its intrinsic catalytic activity and stability under complex flue gas environments. Some strategies, such as nanosize reduction, composite catalysts, and transition metal or rare earth ion doping, have been reported to enhance the catalytic properties. However, the commercialization of CrO_<i>x</i>/Ce_0.2Zr_0.8O₂ is greatly hindered by its poor stability under complex flue gas environments. Herein, we reveal a new route to fabricate N-doped CrO_<i>x</i>/Ce_0.2Zr_0.8O₂ nanoparticles, which exhibit not only higher NO conversion but also H₂O and SO₂ tolerance. The morphology and structure were analyzed via X-ray diffraction, transmission electron microscope, et al., investigating the enhancement of N doping. Additionally, the formation of the Ce–O–N–Zr chemical bond and the possible catalytic mechanism were examined by in situ diffuse reflectance infrared Fourier transform spectroscopy, which provided insight into both the fabrication and the catalytic oxidation activity. Finally, density functional theory calculations were applied to expand the design and afford diverse functionality of the catalyst for use in various applications

Fabrication of a Biomass-Based Hydrous Zirconium Oxide Nanocomposite for Preferable Phosphate Removal and Recovery

Advanced removal of phosphate by low-cost adsorbents from municipal wastewater or industrial effluents is an effective and economic way to prevent the occurrence of eutrophication. Here, we proposed a novel method to immobilize hydrous zirconium oxide nanoparticle within quaternary-aminated wheat straw, and obtained an inexpensive, eco-friendly nanocomposite Ws–N–Zr. The biomass-based Ws–N–Zr exhibited higher preference toward phosphate than commercial anion exchanger IRA-900 when competing sulfate ions coexisted at relatively high levels. Such excellent performance of Ws–N–Zr resulted from its specific hybrid structure, the quaternary ammonium groups bonded on the host favor the preconcentration of phosphate ions inside the wheat straw based on Donnan effect, and the encapsulated HZO nanoparticle exhibits preferable sequestration of phosphate ions through specific interaction, as further demonstrated by FTIR and X-ray photoelectron spectroscopy. Cycle adsorption and regeneration experiments demonstrated that Ws–N–Zr could be employed for repeated use without significant capacity loss, when the binary NaOH–NaCl solution was employed as the regenerant. The influence of solution pH and contact time was also examined. The results suggested that Ws–N–Zr has a great potential in efficient removal of phosphate in contaminated waters