Luxa’s Prism:A Collaborative Ethnography of Im/mobilities in Pandemic Times

The purpose of this chapter is to reflect on the ‘experimental collaborations’ that guided the authors in designing and conducting a collaborative ethnography of the social and geographical mobilities of disadvantaged European youth during the COVID-19 pandemic. The chapter is based on 30 online video conversations between the two authors: an Italian white male postdoctoral researcher and a Romanian Roma woman who spent most of her youth homeless in Madrid. Together, they examine the practical and conceptual implications of collaborative methodologies involving individuals with diverse socioeconomic and experiential backgrounds. They do so by tracing the multiple origins, arrangements and meanings of their collaboration through a deeply reflexive dialogue that recovers and validates their situated memories, emotions and experiences as legitimate sources of ethnographic knowledge. The chapter particularly emphasizes the potential of digital technologies in reconfiguring the modes of ethnographic collaboration, shedding light on the positive role of uncertainty and failure in reducing power asymmetries within participatory research encounter

REGARDING CERTAIN AERODYNAMIC SOURCES OF NON-STATIONARY FORCE LOADS ON TURBINE PROFILES

The paper deals with selected phenomena present in a blade cascade flow field. The presented research was performed on prismatic blade cascades composed mostly of the tip and root sections of the last stage rotor blade of a large output steam turbine. The unstarted supersonic flow on the cascade inlet, the separation of the flow and the swirl line behind the trailing edge have been identified as the possible sources of the unsteady force effects

Shock wave configuration in a transonic flow through a mid-section of a last stage turbine blade cascade equipped with a part-span connector

This paper deals with the study of a flow field and namely the configuration of shock waves in a blade cascade equipped with a part-span connector called tie-boss. The cascade consists of prismatic blades formed from the mid-section of a very long last-stage blade of a steam turbine. The study is based on numerical simulations of the flow through a cascade that was previously tested in a wind tunnel. Commercial software Ansys CFX was used for the simulations and Ansys ICEM for the mesh generation. The computational domain contains non-homogenous mesh interfaces. The simulations showed that the presence of the tie-boss has a profound effect on the configuration of the shock waves. The blade exit shock waves are disturbed and new lateral shock waves are introduced into the flow

Food habits of harbor seals (Phoca vitulina) in two estuaries in northern Puget Sound, Washington

There is a long-held belief that marine mammals are a threat to fishery resources. In Puget Sound, there is particular concern about the potential impacts of pinniped predation on depleted or recovering populations of rocky reef bottomfish. To understand the potential effects of pinnipeds on fish stocks, it is necessary first to describe the types of prey that they consume. The goal of this study was to describe the seasonal diet composition of the Pacific harbor seal (Phoca vitulina) in two estuaries, Padilla Bay and Drayton Harbor. Fecal samples ( scats ) were collected from haul-out sites during pre-pupping (May - June) and pupping (July - September) seasons in 2006. Otoliths and other diagnostic skeletal structures were used to identify prey to the lowest possible taxon. Frequency of occurrence (% FO) was calculated for all prey taxa, and occurrences of the top (\u3e 25% FO) prey species were compared between seasons (Drayton Harbor pre-pupping and pupping), years (Drayton Harbor 1992 and 2006), and sites (Padilla Bay and Drayton Harbor). I also compared seal diet from Padilla Bay and Drayton Harbor with that from non-estuarine haul-out sites in the San Juan Islands. Overall, 40 prey taxa, representing at least 26 taxonomic families, were identified in 198 harbor seal scats from the estuaries. In Padilla Bay, the most common prey were gunnel (family Pholidae), snake prickleback (Lumpenus sagitta), Pacific staghorn sculpin (Leptocottus armatus), and shiner perch (Cymatogaster aggregata). Threespine stickleback (Gasterosteus aculeatus) and Pacific herring (Clupea pallasi) were the most frequently consumed species in Drayton Harbor, and shiner perch, snake prickleback, Pacific staghorn sculpin, mammal, and flatfish also each occurred in more than 50% of samples from at least one season. The majority (\u3e 85%) of samples contained demersal and benthopelagic taxa; pelagic prey were also common in Drayton Harbor diet. Occurrences of top prey taxa varied by season, year, and site. Most top prey species were consumed more frequently during pupping season in Drayton Harbor. The diversity of Drayton Harbor pupping season diet (9.3 ± 2.99 prey taxa/sample) was also significantly higher than pre-pupping season (6.1 ± 2.82 prey taxa/sample) and Padilla Bay pupping season (4.0 ± 1.68 prey taxa/sample) diets. All top prey taxa differed significantly between estuarine and non-estuarine haul-out sites. Diet composition suggested that harbor seals in Padilla Bay and Drayton Harbor foraged primarily within estuarine habitats, such as those found near the haul-out sites, and some Drayton Harbor seals occasionally fed in other habitats (e.g., freshwater). Temporal and spatial variations in diet appeared to reflect differences in the availability of prey taxa, but this was not always the case (e.g., increased predation on Pacific herring between 1992 and 2006). Drayton Harbor represents the first account of mammals as harbor seal prey. Considering the proximity of some northern Puget Sound estuaries to rocky habitats, including the candidate marine reserves in Skagit County, it is necessary to monitor the food habits of harbor seals in various habitats near marine reserves to assess more accurately the degree of predation on depressed fish stocks

REGARDING CERTAIN AERODYNAMIC SOURCES OF NON-STATIONARY FORCE LOADS ON TURBINE PROFILES

The paper deals with selected phenomena present in a blade cascade flow field. The presented research was performed on prismatic blade cascades composed mostly of the tip and root sections of the last stage rotor blade of a large output steam turbine. The unstarted supersonic flow on the cascade inlet, the separation of the flow and the swirl line behind the trailing edge have been identified as the possible sources of the unsteady force effects

Implementation of Federal Waivers for Feeding Children in Early Care and Education During the COVID-19 Pandemic

Objective: To capture Child and Adult Care Food Program (CACFP) state directors’ experiences implementing federal waivers for feeding children in early care and education (ECE) settings during coronavirus disease 2019. Design: Qualitative semistructured interviews. Setting: Virtual interviews with state CACFP directors. Participants: Child and Adult Care Food Program directors from 21 states from December 2020 to May 2021. Phenomenon of Interest: Implementation of state-level waivers. Analysis: Qualitative thematic analysis. Results: State directors reported that the coronavirus disease 2019 waivers allowed ECE programs to continue feeding children despite being closed or having limited enrollment. The meal pattern, noncongregate feeding, parent/guardian meal pick-up, and monitoring waivers were most frequently used by states. Challenges included maintaining integrity to CACFP meal pattern requirements, addressing the limited capacity of ECE to produce and distribute noncongregate meals, and adapting technology for virtual reviews. Suggested improvements included streamlined communication from the US Department of Agriculture, standing waivers for emergencies, ongoing flexibilities for feeding children, and strategies to increase CACFP enrollment and reduce financial viability requirements for ECE. Conclusions and Implications: Results indicate the need for the US Department of Agriculture to consider issuing and extending waivers, increasing ECE participation in CACFP, and ensuring timely communication and guidance on waiver trackin

Electrochemical Decalcification-Exfoliation of Two-Dimensional Siligene, SixGey: Material Characterization and Perspectives for Lithium-Ion Storage

A two-dimensional (2D) silicene-germanene alloy, siligene (SixGey), a single-phase material, has attracted increased attention due to its two-elemental low-buckled composition and unique physics and chemistry. This 2D material has the potential to address the challenges caused by low electrical conductivity and the environmental instability of corresponding monolayers. Yet, the siligene structure was studied in theory, demonstrating the material’s great electrochemical potential for energy storage applications. The synthesis of free-standing siligene remains challenging and therefore hinders the research and its application. Herein we demonstrate nonaqueous electrochemical exfoliation of a few-layer siligene from a Ca1.0Si1.0Ge1.0 Zintl phase precursor. The procedure was conducted in an oxygen-free environment applying a −3.8 V potential. The obtained siligene exhibits a high quality, high uniformity, and excellent crystallinity; the individual flake is within the micrometer lateral size. The 2D SixGey was further explored as an anode material for lithium-ion storage. Two types of anode have been fabricated and integrated into lithium-ion battery cells, namely, (1) siligene-graphene oxide sponges and (2) siligene-multiwalled carbon nanotubes. The as-fabricated batteries both with/without siligene exhibit similar behavior; however there is an increase in the electrochemical characteristics of SiGe-integrated batteries by 10%. The corresponding batteries exhibit a 1145.0 mAh·g-1 specific capacity at 0.1 A·g-1. The SiGe-integrated batteries demonstrate a very low polarization, confirmed by their good stability after 50 working cycles and a decrease in the solid electrolyte interphase level that occurs after the first discharge/charge cycle. We anticipate the growing potential of emerging two-component 2D materials and their great promise for energy storage and beyond.10 página

Shock wave configuration in a transonic flow through a mid-section of a last stage turbine blade cascade equipped with a part-span connector

This paper deals with the study of a flow field and namely the configuration of shock waves in a blade cascade equipped with a part-span connector called tie-boss. The cascade consists of prismatic blades formed from the mid-section of a very long last-stage blade of a steam turbine. The study is based on numerical simulations of the flow through a cascade that was previously tested in a wind tunnel. Commercial software Ansys CFX was used for the simulations and Ansys ICEM for the mesh generation. The computational domain contains non-homogenous mesh interfaces. The simulations showed that the presence of the tie-boss has a profound effect on the configuration of the shock waves. The blade exit shock waves are disturbed and new lateral shock waves are introduced into the flow