Al2O3 aerogels are widely employed in heat insulation and flame retardancy because of their unique combination of low thermal conductivity and exceptional high-temperature stability. However, the mechanical properties of Al2O3 aerogel are poor, and the preparation time is considerably long. In this study, we present a simple and scalable approach to construct monolithic Pal/Al2O3 composite aerogels using solvothermal treatment instead of traditional solvent replacement, which remarkably shortened the preparation time. Subsequently, to obtain stable superhydrophobicity (θ > 152°), the Pal/Al2O3 aerogel was modified by gas-phase modification method. The obtained Pal/Al2O3 composite aerogels demonstrate the integrated properties of low density (0.078–0.106 g/cm3), low thermal conductivity (1000 °C, 0.143 W/(m·K)), good mechanical properties (Young's modulus, 1.6 MPa), and good heat resistance. The monolithic Pal/Al2O3 composite aerogels with improved mechanical performance and improved thermal stability can show great potential in the field of thermal insulation. 相似文献
The round whitefish (Prosopium cylindraceum) is a coregonine native to numerous northern temperate lentic and lotic systems across North America. The St. Marys River, located between the United States and Canadian border, is one such system where the round whitefish supports a recreational fishery and is a prey source for piscivores. Round whitefish are generally known to prey upon benthic macroinvertebrates, but diets of round whitefish in the St. Marys River have not been characterized. We analyzed stomach contents from 107 round whitefish sampled from the St. Marys River during the winter months of 2020 and 2021 to describe their diets, examine their feeding strategies, and determine if they fed selectively. Ephemeropterans were the most important prey numerically, followed by megalopterans, trichopterans, and dipterans. The round whitefish population sampled from the St. Marys River exhibited a specialized feeding strategy that most often specialized on ephemeropterans. Patterns in the importance of prey types and feeding strategy were consistent between both years sampled. Selective feeding by round whitefish was examined using diet and environmental data from 2021 only, and we found that round whitefish selected both ephemeropterans and megalopterans, but avoided trichopterans and dipterans. Rather than being opportunistic invertivores, our results indicate round whitefish are specialized and selective feeders. Our findings can be used to inform conservation and management of round whitefish, as diets represent an integration of multiple ecological components such as prey availability, predator behavior, and habitat quality. 相似文献
Listeria innocua inactivation by pulsed light (PL) was evaluated at different settings and voltages, to establish the best treatment conditions and post-treatment handling for further implementation of PL in the food industry. Fluences up to 0.2 J/cm2 were applied to superficially inoculated TSA agar plates (4.5–5 log cfu/cm2). Inactivation was calculated, and log-linear and Weibull models were applied. A fluence of 0.2 J/cm2 applied in a single pulse inactivated 3.8 log cfu/cm2, while sequential application of this fluence yielded an inactivation between 1.5 and 2.5 log cfu/cm2 depending on the delivery mode (consecutive flashing or with 5 min-holding times under ambient light or in the dark). Data from consecutive PL treatment were fitted with the Weibull model. No photoreactivation following PL was observed after 120-min exposure to ambient light in any of the conditions assayed. This study showed that flashing with a single pulse at higher voltage would offer the highest inactivation of Listeria.Industrial relevanceThis study offered information of practical interest to establish pulsed light processing and post-processing conditions for the control of Listeria spp. in the food industry, for instance in ready-to-eat (RTE) products. The use of higher voltages provided higher inactivation and allowed to minimise the number of flashes. If sequential treatments are to be applied, the treatment is more effective if short holding times are kept between pulses. The post-processing illumination conditions do not influence the efficacy of PL treatment. 相似文献
With rapid socioeconomic and population growth, high-quality arable land resources are decreasing daily, especially in arid areas, which makes arable land reserve resources an important way to supplement arable land. How to accurately evaluate cultivated land reserve resources is of great significance to socioeconomic development and sustainable land use in arid areas. Therefore, this study selected Hangjin Banner as a typical area and calculated the regional maximum available irrigation water based on the principle of regional water balance. Then, the "irrigation area check algorithm" was used to evaluate the amount of cultivated land reserve resources, and policy recommendations were proposed for the development and utilization of cultivated land resources. The results showed that Hangjin Banner had no cultivated land reserve resources under the current irrigation method and had cultivated land reserve resources under the efficient water-saving irrigation method, but only in the southern zone during normal and partially abundant water years. Therefore, we believe that arid areas should adhere to the "set land by water" principle, the allocation of water resources should be optimized, and cultivated land resources with high quality should be utilized based on the actual regional conditions.
Water Resources Management - Climate change will modify the spatio-temporal variation of hydrological variables worldwide, potentially leading to more extreme events and hydraulic infrastructure... 相似文献
Rip currents near coastal structures commonly occur in Lake Michigan in the Great Lakes region of the United States. Lack of timely warning due to undocumented characteristics of rip currents and no assessment tool can contribute to tragic drownings incidents. In this paper, we characterized rip current occurrences near breakwater structures and developed an assessment tool for providing timely rip current warnings to beachgoers at the study site, City of Port Washington, WI. Characteristics of rip currents near the structure were observed from field measurements or visual images. Deflection rip currents had speeds of ~ 0.2 m/s and lasted for several hours. The rip current occurrences were associated with environmental proxies. It was found that rip currents can occur even when the water appears calm near the structure. A Structure Rip Checklist and Assessment Matrix (SRiCAM) with a four-tiered risk was developed and validated using observations. Furthermore, the SRiCAM was integrated into cyberinfrastructure with a data contingency plan to provide real-time warnings to the public. The applicability of the SRiCAM to other locations across Lake Michigan was further tested and results are promising. Overall, the SRiCAM has the potential to be widely extended to foster recreational water safety and resilience to rip current hazards in the Great Lakes. 相似文献
A highly active and stable boron-promoted catalyst was successfully prepared by using the sequential incipient wetness impregnation technique and examined for methane bi-reforming reaction. The initial investigation found that the NiO and B2O3 particles were dispersed on the outer surface of the high surface area SBA-15 support. In addition, the catalytic activity was increased linearly with the tested reaction temperature due to the endothermic nature of the reaction. In fact, the catalyst achieved the CH4 conversion and H2/CO molar ratio of approximately 67.3% and 2.7, respectively at 1073 K. The resulting product ratio is highly suitable for downstream Fischer-Tropsch (FT) synthesis. The B-promoted catalyst showed the lowest degree of catalyst deactivation (4%) at 1023 K. Additionally, the XPS measurements unveiled that the boron facilitates the adsorption of CO2 by donating electrons to the neighbouring Ni cluster and thus improved its catalytic performance. Furthermore, Raman and XRD analysis revealed that the boron promotion on 10%Ni/SBA-15 could prevent the reoxidation and deposition of carbonaceous species. 相似文献