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- ItemNITRIDING OF SUPER-FERRITIC STAINLESS STEEL BY PLASMA IMMERSION ION IMPLANTATION IN RADIO FREQUENCY AND ECR-MICROWAVE PLASMA SYSTEM(IEEE, 2015) Bhuyan, H.; Favre, Mario; Cisternas, M.; Henriquez, A.; Wyndham, E.; Mandl, S.; Manova, D.; Walczak, M.Stainless steel 470 Li-24 Cr and 460Li-21 Cr are two new generation super-ferritic nickel free grades, contains titanium (Ti), niobium (Nb) and very small percentage of carbon (C) and nitrogen (N). The Ti and Nb enhance the corrosion resistance while the low interstitial content of C and N leads to finer precipitates and greater ductility. These grades are economic alternative to 316L and 304 with corrosion resistance comparable or superior. However, as 316L and 304 can be nitrided efficiently to improve the mechanical surface properties like hardness and wear; it has to be asked whether these new generation super-ferritic grade stainless steels can be improved further by plasma nitriding too. Two sets of experiments have been carried out, one with capacitively coupled radio frequency Plasma at PUC Chile and the other is microwave plasma at IOM Leipzig, to investigate further improvements in the mechanical properties of 470 Li-24 Cr and 460Li-21 Cr steel. Nitrided and unnitrided substrates are further investigated using different surface characterization techniques including secondary ion mass spectroscopy, scanning electron microscopy, energy dispersive x-ray analysis, Vickers hardness, wear resistance, corrosion test etc. In most of the characterizations the nitrided 470 Li-24 Cr and 460Li-21 Cr shows similar results. Increase of surface roughness for higher treatment temperature is observed in both the experiments, independent of the steel types. The formation of chromium nitride compound takes place at treatment temperature around 400 o C-450 o C, and it increases with further increase in temperature. But at higher temperature corrosion property deteriorate. The characterization results show up to 25% of nitrogen, 4-5 times increased in hardness and diffusion of nitrogen layer up to 4-6 micron for different experimental conditions. The samples implanted with temperature higher than 400°C presented wear resistance values around two orders of magnitude higher than the others.
- ItemNatural enemy communities of aphids in alfalfa fields assessed through video recordings of sentinel cards in scenarios of contrasting aphid abundance(2024) Grez, Audrey A.; Zaviezo, Tania; Molina, GabrielaThe first step to better understand the relationship between natural enemy communities and pest control is to know which, when, and how frequently different natural enemies interact with their prey. In alfalfa fields of central Chile, aphids are the most common pests and are consumed by predators such as coccinellids, syrphids, and spiders. In this study, through video recording, we analyzed how natural enemy communities visiting aphid sentinel cards vary between scenarios of low and high abundance of aphids in alfalfa in spring. On 15 occasions, during the day, we monitored the natural enemies visiting cards with sentinel aphids (60 cards per field; total 900) located in fields with high (n = 6) and low (n = 9) aphid abundance. We also analyzed whether the abundance of coccinellid species visiting sentinel cards was related to their abundance in each field. In 750 h of video recording, we found 2749 natural enemies visiting the sentinel cards; 86.2% of them were coccinellids of five species. Total natural enemies and coccinellid visits were three times higher in low than in high aphid abundance scenarios. In contrast, the species richness and diversity of natural enemies and coccinellids visiting cards did not differ between aphid scenarios. The abundance of coccinellids in the field was positively associated with the abundance of coccinellids visiting cards, for the three most abundant species. Our study shows that video recording is useful for identifying changes in the communities of natural enemies of aphids in alfalfa, providing important new insights into trophic interactions in field situations.
- ItemFormation and Morphology of Single Phospholipid Bilayers Formed by Velocity-Controlled Dip-Coating(2018) Cisternas Fruns, Marcelo Andrés; Soto Arriaza, Marco Antonio; Retamal Ponce, Maria Jose; Moraga Alarcón, Nicolás Hernán; Catalán Lopez, Rodrigo Esteban; Volkmann, Ulrich Georg; Diaz, Diego; Corrales, Tomas P.
- ItemProposed Model to Understand Coping Mechanisms Development in Athletes Living with Type 1 Diabetes to Address Physical Activity Barriers(Mary Ann Liebert, Inc., publishers, 2024) Montt Blanchard, DeniseBackground and Aims: Individuals with Type 1 diabetes (T1D) often face distinct hurdles in high‐performance sports, with some athletes using coping mechanisms that remain poorly understood. This study explores the significance of these coping mechanisms in overcoming T1D‐related barriers in competitive physical activities among young and adult patients in Chile. By delving into these mechanisms, the study aims to bridge knowledge gaps in T1D management within high‐performance sports, ultimately promoting physical activity for individuals with T1D. Methods: An interdisciplinary patient‐centered approach was employed in this study. In‐depth interviews were conducted with thirty competitive athletes with T1D who participated in any Olympic sport at a competitive level. The interviews were transcribed verbatim and analyzed using QcaMap. Thematic analysis was carried out by professionals from behavioral sciences and design to comprehensively examine the coping mechanisms of the participants. Results: The study reveals three key insights for T1D self‐management in high‐performance sports: negative influences driving competitive training motivation, physical coping mechanisms for diabetes, and positive outcomes impacting performance. Examined through psychological behavior theory, these insights deepen our understanding of T1D management in sports. Conclusions: This research provides insights into how athletes with T1D overcome physical activity barriers, offering a model for understanding strategies. These insights can guide inclusive design solutions to promote physical activity in T1D, linking behavioral science and design. This interdisciplinary approach contributes to health psychology and design management, potentially enhancing lives and athletic performance of individuals with T1D while inspiring innovations in diabetes care and physical activity promotion.
- ItemDevelopment and Operationalisation of Local Sustainability Indicators - A Global South Perspective on Data Challenges and Opportunities for GIScience(Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing, 2023) Steiniger, Stefan; Rojas Quezada, Carolina Alejandra; Truffello Robledo, Ricardo Enrique; Barton Jonathan, RichardEvaluating and monitoring the sustainable development of nations and cities requires sets of indicators. Such indicator sets should measure equity, health, environmental, or governmental progress or recess - among other sustainability aspects. In 2015 the United Nations ratified 17 Sustainable Development Goals (SDG) assessed through 231 indicators. However, other - local - sets of indicators have been developed too. In this paper we review geodata challenges that emerged when we developed four sustainability indicator sets in Chile. Faced challenges include (geo)data availability and data representativeness, among others. We analyse how GIScience knowledge has contributed to indicator development and outline three priority research topics: (i) updating indicators based on automated processes, while respecting representativeness, (ii) tools for planning scenario generation, and (iii) methods for short- and long-term forecasting.