Research on Wear Characteristics and Experiment on Internal Through-Passage Components for a New Type of Deep-Sea Mining Pump

The conveyor electric pump for deep-sea mining is a key piece of equipment in deep-sea mineral transportation systems, as its flow capacity and wear resistance affect the reliability of the entire system. In this study, aimed at solving problems such as mining pumps being prone to clogging and wear, which could lead to performance degradation, a mining pump with wide flow paths and high performance was designed, and hydraulic performance tests were conducted on the new pump. The test results obtained were in good agreement with the numerical simulation results. Based on the reliability of the performance test results, using computational fluid dynamics (CFD) methods, and taking the wear model into consideration, a wear analysis was conducted on the internal through-passage components of the pump under different solid-phase particle parameters and operating conditions, and the average wear rate on the surface of the predominant through-passage components was calculated. The results showed that the hydraulic performance of the newly designed pump met the design requirements, with different particle parameters and operating conditions causing different degrees of wear on the through-passage components. The wear test was carried out with a test pump, and the comparison between the test results and the numerical calculation results showed that the numerical calculation of the wear of the deep-sea mining pump was accurate.

Quantification and Characterisation of Nano-Sized Particles in Cryoprecipitate Units

Background Cryoprecipitate is an important blood product derived from fresh frozen plasma. It is primarily used to replenish fibrinogen levels in patients. Currently, there is a lack of studies characterising nano-sized particles, including extracellular vesicles (EVs) in cryoprecipitate. EVs play a key role in cell-to-cell communication in physiological and pathological conditions, through the transference of their bioactive cargo such as proteins, lipids, or nucleic acids. This study utilised modern techniques such as nanoparticle tracking analysis (NTA) to characterise these EVs. Methods We obtained ten individual cryoprecipitate units and determined their particle concentration and size distribution using optimised NTA parameters on the Nanosight NS300 instrument. To prevent blockage of the Nanosight's micro-fluidics, samples are routinely filtered before sample injection. Therefore, we wanted to investigate if different filter materials could impact NTA measurements for cryoprecipitate. Samples were filtered with either regenerated cellulose (RC) or polytetrafluoroethylene (PTFE), with non-filtered samples as control. A one-way ANOVA with Tukey post hoc test was used to compare the particle parameters (particle concentration, mean, mode). Significance was set at p<0.05. Results The results showed that different cryoprecipitate units varied in their particle concentration and size, with an average concentration of 2.501 x 10 11 ± 1.098 x 10 11 particles per mL and a particle mean of 133.8 ± 7.5 nm and mode of 107.9 ±11.06 nm. In addition, only samples filtered using RC were there no significant changes in the measured particle parameters (particle concentration, p=0.936; mean, p=0.999; mode, p=0.996) compared to the non-filtered samples. A significant difference was observed in the mean of particle size between PTFE and RC filters (112.7 ± 6.033 nm, 42 133.8 ± 7.503 nm, p =<0.0001) and between PTFE and non-filtered (112.7 ± 6.033 nm, 133.7 ± 13.63 nm, p =0.0015). PTFE significantly reduced the particle mean compared to both RC and non-filtered. Conclusions Our findings revealed that NTA could be used as a novel method to measure particles in cryoprecipitate. Furthermore, RC filters are compatible with quantitative NTA analysis compared to PTFE filters. Disclosures No relevant conflicts of interest to declare.

Influence of Different Alloying Strategies on the Mechanical Behavior of Tool Steel Produced by Laser-Powder Bed Fusion

Additive manufacturing is a high-potential technique that allows the production of components with almost no limitation in complexity. However, one of the main factors that still limits the laser-based additive manufacturing is a lack of processable alloys such as carbon martensitic hardenable tool steels, which are rarely investigated due to their susceptibility to cold cracking. Therefore, this study aimed to expand the variety of steels for laser powder bed fusion (L-PBF) by investigating an alternative alloying strategy for hot work tool steel powder. In this study, a comprehensive investigation was performed on the powder and L-PBF processed specimen properties and their correlation with the existing defects. Cubical specimens were created using the following two alloying strategies by means of L-PBF: conventional pre-alloyed gas-atomized powder and a mixture of gas-atomized powder with mechanically crushed pure elements and ferroalloys. The influence of the particle parameters such as morphology were correlated to the defect density and resulting quasi-static mechanical properties. Micromechanical behavior and damage evolution of the processed specimens were investigated using in situ computed tomography. It was shown that the properties of the L-PBF processed specimens obtained from the powder mixture performs equal or better compared to the specimens produced from conventional powder.

A Self-Consistent Scheme for Understanding Particle Impact and Adhesion in the Aerosol Deposition Process

Aerosol deposition (AD) is a thick-film deposition process that can produce films tens to hundreds of micrometers thick with densities greater than 95% of the bulk at room temperature. However, the precise mechanisms of bonding and densification are still under debate. To better understand and predict deposition, a self-consistent approach is employed that combines computational fluid dynamics (CFD), finite element (FE) modeling, and experimental observation of particle impact to improve the understanding of particle flight, impact, and adhesion in the AD process. First, deposition is performed with a trial material to form a film. The process parameters are fed into a CFD model that refines the particle flow and impact velocity for a range of sizes. These values are in turn used to inform the FE parameters to model the fracture and adhesion of the particle on the substrate. The results of FE modeling are compared to SEM images of fractured particles to complete a self-consistent numerical and experimental understanding of the AD process. Additional FE and CFD simulations are used to study how process parameters, materials, and particle parameters affect the deposition process and how the developed tools can be used to optimize deposition efficiency.

Development of international key comparisons in the field of chemico-analytical measurements

The most challenging goals in the field of chemico- and bioanalytical measurements are described. Solutions of these problems are presented, which are being solved in particular by participating in new international comparisons organized by the Cosultative Committee on the Amount of Substance of the International Committee on Weights and Measures (CCQM CIPM). The purposes and tasks of developing key comparisons in the following areas are described: isotopic measurements; determination of the purity of substances; organic analysis; bioanalytical measurements; measurements of aerosol particle parameters; measurements in the field of gas analysis and electrochemistry. It is shown that participation in international key comparisons makes it possible to obtain valid and reliable results of measurements of the composition and properties of gas and liquid media, as well as solid substances and materials.