Routine habitat switching alters the likelihood and persistence of infection with a pathogenic parasite

Animals switch habitats on a regular basis, and when habitats vary in suitability 21 for parasitism, routine habitat switching alters the frequency of parasite exposure 22 and may affect post-infection parasite proliferation. However, the effects of 23 routine habitat switching on infection dynamics are not well understood. 24 2. We performed infection experiments, behavioural observations, and field 25 surveillance to evaluate how routine habitat switching by adult alpine newts 26 (Ichthyosaura alpestris) influences infection dynamics of the pathogenic parasite, 27 Batrachochytrium dendrobatidis (Bd). 28 3. We show that when newts are exposed to equal total doses of Bd in aquatic 29 habitats, differences in exposure frequency and post-exposure habitat alter 30 infection trajectories: newts developed more infections that persisted longer when 31 doses were broken into multiple, reduced-intensity exposures. Intensity and 32 persistence of infections was reduced among newts that were switched to 33 terrestrial habitats following exposure. 34 4. When presented with a choice of habitats, newts did not avoid exposure to Bd, 35 but heavily infected newts were more prone to reduce time spent in water. 36 5. Accounting for routine switching between aquatic and terrestrial habitat in the 37 experiments generated distributions of infection loads that were consistent with 38 those in two populations of wild newts. 39 6. Together, these findings emphasize that differential habitat use and behaviours 40 associated with daily movement can be important ecological determinants of 41 infection risk and severity. 4

Time-temperature-transformation diagram within the bainitic temperature range in a medium carbon steel

The time-temperature-transformation (ITT) diagram within the medium temperature range of medium carbon steel has been determined. A single type of C-curve is found within the bainite temperature range for the studied steel. Distinct reaction C-curves were not observed for both types of microstructure, upper bainite and lower bainite in the TTT diagram. Experimental results on the kinetics of the isothermal formation of bainite at different temperature have demonstrated that both type of microstructure, upper and lower bainite, possesses similar overall transformation kinetics. Some applications of phase transformation theory towards the formation of bainitic microstructures are discussed, with particular emphasis on the bainite start temperature, transition temperature from upper to lower bainite, martensite start temperature and the thickness of bainitic plates.Peer Reviewe

Nitrogen uptake of nickel free austenitic stainless steel powder during heat treatment-an XPS study

In austenitic stainless steel nitrogen stabilizes the austenitic phase, improves the mechanical properties and increases the corrosion resistance. Nitrogen alloying enables to produce austenitic steels without the element nickel which is high priced and classified as allergy inducing. A novel production route is nitrogen alloying of CrMn-prealloyed steel powder via the gas phase. This is beneficial as the nitrogen content can be adjusted above the amount that is reached during conventional casting. A problem which has to be overcome is the oxide layer present on the powder surface which impedes both the sintering process and the uptake of nitrogen. This study focuses on whether heat treatment under pure nitrogen is an appropriate procedure to enable sintering and nitrogen uptake by reduction of surface oxides. X-ray photoelectron spectroscopy (XPS) in combination with scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) are used to investigate the surface of powdered FeMn19Cr17C0.4N heat treated under nitrogen atmosphere. The analyses showed reduction of iron oxides already at 500 degrees C leading to oxide-free metallic surface zones. Mn and Cr oxides are reduced at higher temperatures. Distinct nitrogen uptake was registered, and successful subsequent sintering was reached

Nitrogen uptake of nickel free austenitic stainless steel powder during heat treatment-an XPS study

In austenitic stainless steel nitrogen stabilizes the austenitic phase, improves the mechanical properties and increases the corrosion resistance. Nitrogen alloying enables to produce austenitic steels without the element nickel which is high priced and classified as allergy inducing. A novel production route is nitrogen alloying of CrMn-prealloyed steel powder via the gas phase. This is beneficial as the nitrogen content can be adjusted above the amount that is reached during conventional casting. A problem which has to be overcome is the oxide layer present on the powder surface which impedes both the sintering process and the uptake of nitrogen. This study focuses on whether heat treatment under pure nitrogen is an appropriate procedure to enable sintering and nitrogen uptake by reduction of surface oxides. X-ray photoelectron spectroscopy (XPS) in combination with scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) are used to investigate the surface of powdered FeMn19Cr17C0.4N heat treated under nitrogen atmosphere. The analyses showed reduction of iron oxides already at 500 degrees C leading to oxide-free metallic surface zones. Mn and Cr oxides are reduced at higher temperatures. Distinct nitrogen uptake was registered, and successful subsequent sintering was reached

Influence of the PM-Processing Route and Nitrogen Content on the Properties of Ni-Free Austenitic Stainless Steel

Ni-free austenitic steels alloyed with Cr and Mn are an alternative to conventional Ni-containing steels. Nitrogen alloying of these steel grades is beneficial for several reasons such as increased strength and corrosion resistance. Low solubility in liquid and δ-ferrite restricts the maximal N-content that can be achieved via conventional metallurgy. Higher contents can be alloyed by powder-metallurgical (PM) production via gas–solid interaction. The performance of sintered parts is determined by appropriate sintering parameters. Three major PM-processing routes, hot isostatic pressing, supersolidus liquid phase sintering (SLPS), and solid-state sintering, were performed to study the influence of PM-processing route and N-content on densification, fracture, and mechanical properties. Sintering routes are designed with the assistance of thermodynamic calculations, differential thermal analysis, and residual gas analysis. Fracture surfaces were studied by X-ray photoelectron spectroscopy, secondary electron microscopy, and energy dispersive X-ray spectroscopy. Tensile tests and X-ray diffraction were performed to study mechanical properties and austenite stability. This study demonstrates that SLPS process reaches high densification of the high-Mn-containing powder material while the desired N-contents were successfully alloyed via gas–solid interaction. Produced specimens show tensile strengths >1000\ua0MPa combined with strain to fracture of 60\ua0pct and thus overcome the other tested production routes as well as conventional stainless austenitic or martensitic grades