Strength and hardness enhancement and slip behaviour of high-entropy carbide grains during micro-compression and nanoindentation

Bulk polycrystalline high-entropy carbides are a newly developed group of materials that increase the limited compositional space of ultra-high temperature ceramics, which can withstand extreme environments exceeding 2000°C in oxidizing atmospheres. Since the deformability of grains plays an important role in macromechanical performance, we studied the strength and slip behaviour of grains of a spark-plasma sintered (Hf-Ta-Zr-Nb)C high-entropy carbide in a specific orientation during micropillar compression. Additionally, the hardness of grains of different orientations was investigated by nanoindentation. For comparison, identical measurements were carried out on the monocarbides HfC and TaC. Four micropillars were fabricated by focused ion beam (FIB) in visibly pore free regions of large (Hf-Ta-Zr-Nb)C, HfC and TaC grains of a specific orientation (Φ~14° and φ2~45°) selected by electron backscatter diffraction (EBSD). This resulted in equal Schmid factors for both the and slip systems, which were reported to operate in HfC and TaC. It was revealed that (Hf-Ta-Zr-Nb)C had a significantly enhanced yield and failure strength compared to the corresponding base monocarbides, while maintaining a similar ductility to the least brittle monocarbide (TaC) during the operation of slip systems (Fig. 1). Nanoindentation investigations revealed a significant enhancement in hardness (~30%) of the high entropy (Hf-Ta-Zr-Nb)C material compared to that calculated according to the rule of mixtures from the base monocarbides (HfC, TaC, ZrC, NbC) and in comparison to the hardest monocarbide (HfC). Additionally, it was concluded that the much larger strength enhancement of micropillars compared to the average nanohardness of randomly oriented grains is attributed to the different slip systems. For (Hf-Ta-Zr-Nb)C, the operation of was identified in micropillar experiments, but the dominant slip system in nanoindentation is assumed to be the , possibly via the activation of partial dislocations, which is attributed to the different Schmid factors due to the different stress fields between nanoindentation and micropillar compression. Please click Additional Files below to see the full abstract

The free d-aspartic acid and d-glutamic acid content of sheep milk and sheep milk products

The role of D-amino acids of foods in the human health is a strongly discussed topic and usually, data came from the investigation of cow milk. We have studied the free D-aspartic acid and free D-glutamic acid content of sheep milk, heat-treated sheep milk at various temperatures and various products of sheep milk. Raw sheep milk didn’t contain free D-aspartic and D-glutamic acid in remarkable amount and ratio 5.92% free D-aspartic acid; 2.62% free D-glutamic acid). Our heat-treatments didn’t cause major change in the free D-aspartic and D-glutamic acid content (max.: 7.8% free D-aspartic acid; 5.3% free D-glutamic acid in total free aspartic and glutamic acid). Contrary, all of the investigated products contained high level of free D-amino acids. The free D-aspartic acid and free D-glutamic acid content of the products were 16,9-39,5%,and 13,3-27% in the percent of total free amino acids. The racemization of aspartic acid was higher, than that of glutamic acid in every product. The D-amino acid content of fermented milk products was higher than in different cheeses

Plasticity of ZrB2 grains during micropillar compression: The effect of anisotropy, temperature and dislocations

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Examination of whey de-fatting by enhanced membrane filtration

The largest quantities of by-products of dairy processing originates from the cheese making. Whey proteins are used for animal feeding and human nutrition as well, for example in dry soups, infant formulas, and supplements. The fat components of the whey might impair its use. The aim of our experiments was to investigate the separation of the lipid fraction of whey. The microfiltration is said to be a gentle and energy efficient method for this task. During the measurements 0.2 μm microfiltration membranes were used and the membrane separation was enhanced by vibration, inserting static mixer and air sparging. The de-fatting efficiency, the retention of the whey components, the flux values, and the resistances in different combinations were compared in this paper

Low rate of asymptomatic cerebral embolism and improved procedural efficiency with the novel pulmonary vein ablation catheter GOLD: results of the PRECISION GOLD trial

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Hospitality, Culture and Regeneration: Urban decay, entrepreneurship and the "ruin" bars of Budapest

This paper considers the relationships between hospitality, culture and urban regeneration through an examination of rom (ruin) venues, which operate in dilapidated buildings in Budapest, Hungary. The paper reviews previous work on culture and urban regeneration in order to locate the role of hospitality within emerging debates. It subsequently interrogates the evolution of the rom phenomenon and demonstrates how, in this context, hospitality thrives because of social and physical decay in urban locations, how operators and entrepreneurs exploit conflicts among various actors involved in regeneration, and how hospitality may be mobilised purposefully in the regeneration process. The paper demonstrates how networked entrepreneurship maintains these operations and how various forms of cultural production are entangled and mobilised in the venues’ hospitality propositions

The influence of health systems on breast, cervical and colorectal cancer screening: an overview of systematic reviews using health systems and implementation research frameworks.

Objectives Screening for breast, cervical and colorectal cancer in an average-risk population is widely recommended in national and international guidelines although their implementation varies. Using a conceptual framework that draws on implementation and health systems research, we provide an overview of systematic literature reviews that address health system and service barriers or facilitators to effective cancer screening. Methods Using a systematic approach, we searched Cochrane Database of Systematic Reviews, Ovid Medline, Ovid Embase, Web of Science, PsychInfo and other internet sources. We included systematic reviews of screening interventions (i.e. targeting people at average risk) for breast, cervical and colorectal cancer. The analysis included 90 systematic reviews. Results This review identified a multitude of barriers and facilitators affecting the health system, the capabilities of individuals in the system and their intentions. A large proportion of the available evidence focused on uptake. The reviews demonstrated that health system factors influenced participation, as well as quality and effectiveness of the service provided. The barriers with the biggest impact were knowledge/education, mainly of clients but also providers (capability barriers) and beliefs and values (intention barriers) of the eligible population. These findings complement the usual focus on psychological and social barriers to informed participation by individuals that dominate the screening literature. The facilitators with the most supporting evidence were educational interventions (overcoming capability and intention barriers), invitation letters, reminders and appointments. These were mainly directed at eligible individuals and, to a lesser extent, to providers and healthcare professionals. Only a small number of reviews, mainly from Europe, specified organized, rather than opportunistic, screening programmes. In those, low participation was the most frequently cited barrier and invitation letters (including physician endorsement, phone calls and reminders to non-responders and healthcare professionals) were the most prevalent facilitators. Conclusion Despite evidence of barriers and facilitators to screening participation and opportunistic screening, further health systems research covering the entire screening system for organized programmes is required. </jats:sec