How are grain sizes of sandstones determined?5 answersGrain sizes of sandstones are determined using various methods such as dry-sieving procedures, laser diffraction particle analysis, and computer vision-based methodologies. Dry-sieving is commonly employed for grain-size analysis of sandstones, providing insights into depositional environments and hydrodynamic conditions. Laser diffraction particle analysis offers a quick and reliable alternative, especially for analyzing a large number of samples, assuming successful disaggregation. Additionally, a computer vision-based methodology has been proposed to extract grain-size and textural parameters from micro-CT surveys of clean sandstones, offering a cost-effective and time-efficient approach for obtaining such information. These diverse methods cater to different needs and sample types, ensuring comprehensive analysis of grain sizes in sandstones.
What type of differences in grain size distribution can be expected between marine sediments and fluvial sediments?5 answersDifferences in grain size distribution between marine and fluvial sediments are notable. Marine sediments typically exhibit sensitivity to sediment sources and hydrodynamic conditions, with parameters like mean size and sorting coefficient showing stability across different calculation methods. In contrast, fluvial sediments are influenced by hydraulic sorting, leading to the development of a 'grain size gap' due to size-selective transport processes. The depositional environment plays a crucial role, with marine sediments often showing dominance of unimodal pure sand from Nile sources, while fluvial sediments demonstrate a mix of suspension and saltation modes influenced by marine and turbidity actions. Additionally, the spatial distribution in estuarine environments like the Sebou estuary indicates a mix of silt and clay sediments derived from offshore and catchment areas.
How can i create a processing map for hot forming of a magnesium alloy?4 answersA processing map for hot forming of a magnesium alloy can be created by conducting isothermal compression tests at different temperatures and strain rates. The data obtained from these tests can be used to develop a constitutive equation model, such as the Arrhenius model, which describes the relationship between stress, strain rate, and temperature. The processing map can then be constructed using criteria such as power dissipation efficiency and instability analysis. The map helps identify the optimum processing parameters, such as temperature and strain rate, for hot working of the magnesium alloy. Microstructural observations can also be used to validate the processing map. The map provides a visual representation of the material's hot workability and can be used to optimize the hot forming process.
How does rolling influence the grain size?5 answersRolling influences the grain size of the material being rolled. The application of compressible forces during rolling leads to plastic deformation of the material, resulting in elongated grains and decreased grain size at the final stage of rolling. Additionally, applying axial tension and transverse load during rolling can induce an enhanced average grain size in the rolled metal section. However, the effect of rolling temperature on grain size is more complex, as the grain size may not always refine as the temperature decreases. The behavior of deformation and recrystallization in austenite during rolling can affect the grain size. The average grain size of a material can also impact the residual stress generated after processing, with fine-grained steels expected to have improved mechanical properties.
Whats the differentiation beween nfq mgb3 answersNfq and MGB are both types of probes used in molecular assays. Nfq stands for "Newcastle disease virus" and MGB stands for "minor groove-binding." Nfq probes are used for the detection and differentiation of avian paramyxovirus type 1 (APMV-1), also known as Newcastle disease virus, which is a serious pathogen of poultry. On the other hand, MGB probes are used in various assays for different purposes. In the context of the first paper, MGB probes are used in a rapid one-step fluorescent quantitative PCR assay to discriminate between wild-type strains and hog cholera lapinized virus (HCLV) strain of classical swine fever virus (CSFV). In the context of the second paper, MGB probes are used in real-time reverse transcription polymerase chain reaction (RT-PCR) assays for the broad range detection and simultaneous pathotyping of APMV-1. Therefore, the differentiation between Nfq and MGB lies in their specific applications in different molecular assays for the detection and differentiation of specific pathogens.
Mg-based binary alloys for electrochemical hydrogen storage?5 answersMg-based binary alloys have been extensively studied for electrochemical hydrogen storage. These alloys possess high capacity, good electrochemical properties, and moderate hydrogen equilibrium pressure, making them attractive for high-performance Ni-MH batteries. The use of rare earth-Mg-Ni-based (R-Mg-Ni-based) alloys with superlattice structures has shown promise in improving the thermodynamic and kinetic properties of these alloys. Various processing routes, such as mechanical alloying and severe plastic deformation, have been explored to optimize the microstructure and enhance the hydrogen storage performance of Mg-based alloys. Additionally, the addition of catalysts, such as Dy2O3, has been found to improve the kinetics of hydrogen absorption and desorption in Mg-based alloys. Overall, Mg-based binary alloys show potential for electrochemical hydrogen storage, and further research is needed to develop alloys with higher energy density, longer cycle life, better kinetics, and lower cost.