13 research outputs found
11â23% Cr steels for solid oxide fuel cell interconnect applications at 800 \ub0C â How the coating determines oxidation kinetics
The present work investigates the low-cost steels AISI 441, AISI 430, and AISI 444 against the tailor-made high Cr steel Crofer 22 APU (22.9 wt% Cr) at 800 \ub0C in simulated solid oxide fuel cell (SOFC) cathode conditions. Furthermore, a low Cr steel, AISI 409 (11.4 wt% Cr) is included in the study. The oxidation, chromium evaporation, and area-specific resistance (ASR) of the uncoated and Ce/Co-coated steels are studied for up to 3000 h. Ce/Co-coated steels showed significant improvement in behaviour compared to their uncoated counterparts. The oxidation and chromium evaporation behaviour between the uncoated steels varied substantially while the Ce/Co coated steels exhibited highly similar behaviour. The area-specific resistance of the coated low-cost steels was on par with Crofer 22 APU. However, 430 formed a continuous silica layer, resulting in a higher ASR after 3000 h. Cross-sections of the uncoated and Ce/Co-coated steels were analysed using a scanning electron microscope and energy dispersive X-ray spectroscopy
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COVID-19, systemic crisis, and possible implications for the wild meat trade in sub-Saharan Africa
Wild animals play an integral and complex role in the economies and ecologies of many
countries across the globe, including those of West and Central Africa, the focus of this
policy perspective. The trade in wild meat, and its role in diets, have been brought into
focus as a consequence of discussions over the origins of COVID-19. As a result, there
have been calls for the closure of Chinaâs âwet marketsâ; greater scrutiny of the wildlife
trade in general; and a spotlight has been placed on the potential risks posed by growing human populations and shrinking natural habitats for animal to human transmission of
zoonotic diseases. However, to date there has been little attention given to what the consequences of the COVID-19 economic shock may be for the wildlife trade; the people who
rely on it for their livelihoods; and the wildlife that is exploited. In this policy perspective,
we argue that the links between the COVID-19 pandemic, rural livelihoods and wildlife
are likely to be more complex, more nuanced, and more far-reaching, than is represented in
the literature to date. We develop a causal model that tracks the likely implications for the
wild meat trade of the systemic crisis triggered by COVID-19. We focus on the resulting
economic shockwave, as manifested in the collapse in global demand for commodities such
as oil, and international tourism services, and what this may mean for local African economies and livelihoods. We trace the shockwave through to the consequences for the use
of, and demand for, wild meats as households respond to these changes. We suggest that
understanding and predicting the complex dynamics of wild meat use requires increased
collaboration between environmental and resource economics and the ecological and conservation sciences
Social Correlates of and Reasons for Primate Meat Consumption in Central Amazonia
Traditionally, humans have consumed nonhuman primates in many places, including throughout the Amazon region. However, primate consumption rates are changing with rising urbanization and market access. We characterize primate consumption in central Amazonia using 192 qualitative interviews with inhabitants in three rural villages and in the city of Tefé. We used a generalized linear model to investigate how individual consumer characteristics, such as age and gender, and livelihoods affected primate consumption. We also used principal coordinate analysis (PCoA), and word clouds and network text analyses, to describe reasons people gave for eating or avoiding primates. Our results show that men were more likely to say that they eat primates than women, and that the probability that a person said that they eat primates correlated positively with the percentage of their life lived in rural areas. People gave sentiment and ethical reasons not to eat primates. Custom influenced whether people said they eat primates both positively and negatively, while taste positively influenced whether people said they eat primates. A preference for other wild meats in rural areas, and for domestic meats in cities negatively influenced whether people said they eat primates. People also cited the perceptions that primates have a human-like appearance and that primate meat is unhealthy as reasons not to eat primates. People in urban areas also cited conservation attitudes as reasons for not eating primates. Our findings provide an understanding of factors influencing primate consumption in our study area and will be useful for designing tailored conservation initiatives by reducing hunting pressure on primates in rural settings and increasing the effectiveness of outreach campaigns in urban centers
Substantial plasticity of reproduction and parental care in response to local resource availability in a wild clownfish population
Plasticity, the capacity of individuals to respond to changing environments by modifying traits, may be critically important for population persistence by allowing for adaptive responses on shorter timescales than genetic change. Here, we use the clown anemonefishAmphiprion percula, whose access to resources is constrained by their anemones, to test the role of plasticity in generating variation in reproductive success among groups. We surveyed a wild clownfish population and found positive correlations between anemone area, fish size, reproduction and parental care. We used structural equation modeling to test the hypothesis that these correlations emanate from variation in anemone area and found support for a pathway linking anemone area to female investment, female investment to male investment and male investment to embryo survival. Next, we experimentally tested whether plasticity in response to resource availability can result in variation in parental traits using a feeding manipulation and found substantial plasticity in reproduction and parental care in response to changes in the availability of food resources. The results of this study reveal the role of plasticity in response to local resource availability in generating variation among individuals in reproductive strategies, linking studies of behavior and demography in this model species, and ultimately contributing to our ability to predict how populations might cope with environmental changes
One hundred priority questions for the development of sustainable food systems in Sub-Saharan Africa
Sub-Saharan Africa is facing an expected doubling of human population and tripling of food demand over the next quarter century, posing a range of severe environmental, political, and socio-economic challenges. In some cases, key Sustainable Development Goals (SDGs) are in direct conflict, raising difficult policy and funding decisions, particularly in relation to trade-offs between food production, social inequality, and ecosystem health. In this study, we used a horizon-scanning approach to identify 100 practical or research-focused questions that, if answered, would have the greatest positive impact on addressing these trade-offs and ensuring future productivity and resilience of food-production systems across sub-Saharan Africa. Through direct canvassing of opinions, we obtained 1339 questions from 331 experts based in 55 countries. We then used online voting and participatory workshops to produce a final list of 100 questions divided into 12 thematic sections spanning topics from gender inequality to technological adoption and climate change. Using data on the background of respondents, we show that perspectives and priorities can vary, but they are largely consistent across different professional and geographical contexts. We hope these questions provide a template for establishing new research directions and prioritising funding decisions in sub-Saharan Africa