Exit flow from a transonic compressor rotor

September 1975Includes bibliographical references (page 6-8)Summary: The three dimensional unsteady flow field behind a transonic compressor rotor with a design pressure ratio of 1.6 at a tip Mach number of 1.2 has been resolved on the blade-passing time scale, using the M.I.T. Blowdown Compressor Facility. Quantities determined were total and static pressures, tangential flow angle and radial flow angle. The spatial and temporal resolution achieved was sufficient to determine velocity components inside individual blade wakes and in the surrounding flow. From these measurements the flow structure is described at stations immediately behind the rotor and one chord downstream. Some dominant features of the flow just behind the rotor are large radial velocity components, large static pressure fluctuations near the blade wakes, and definite unsteadiness (in rotor coordinates) of the wakes. The wake behavior one chord downstream is described in terms of the effect of the strong mean swirl on the behavior of shear disturbances. In the outer portion of the annulus, where the mean flow approximates a solid body rotation, a strong, persistent oscillatory flow is found with 16 periods in the circumference as roughly predicted by theory. In the inner portion of the annulus the disturbances attenuate axially.This research was supported in part by the NASA Lewis Research Center under Grant NGL 22-009-383Supported in part by the Pratt & Whitney Aircraft Division, United Technology Corporation, and the General Electric Compan

A typology of responsibility for coastal flood risk adaptation

The management of coastal flood risk is adapting to meet the challenges and increased risks posed by population change as well as by climate change, especially sea level rise. Protection is being targeted to areas where the benefits are highest, while elsewhere there is a shift towards more localized “living with floods” and “resilience” approaches. Such decentralized approaches to flood risk management (FRM) require a diverse range of stakeholder groups to be engaged as “flood risk citizens”. Engagement of households in FRM is central to this process. Despite significant research on stakeholder engagement in coastal and flood risk management, there is less focus on the nature of responsibility in coastal adaptation. There is no framework by which to assess the different types of responsibility in hazard management and adaptation, and little research on the implications of expecting these responsibilities of stakeholder groups. In this paper, we identify five types of responsibility that are embedded throughout the disaster risk reduction cycle of managing coastal flooding. We build this ”typology of responsibility” on existing work on the evolution of stakeholder engagement and stakeholder responsibility relationships in risk management processes, and a dataset of institutional stakeholder interviews and households surveys conducted across three case studies in England, the United Kingdom, in 2018 and 2019. We analyze the interviews using thematic analysis to explore institutional stakeholder perceptions of responsibility in coastal FRM, and analyze the household survey through descriptive and inferential statistics. By developing the first disaster risk reduction focused typology of responsibility for coastal flooding, we provide researchers and decision-makers with a tool to guide their planning and allocation of responsibilities in risk management for floods and other climate-driven hazards

Searching for life with rovers: exploration methods and science results from the 2004 field campaign of the “Life in the Atacama” project and applications to future Mars Missions

LITA develops and field tests a long-range automated rover and a science payload to search for microbial life in the Atacama. The Atacama's evolution provides a unique training ground for designing and testing exploration strategies and life detection methods for the search for life on Mars

Participatory analysis for adaptation to climate change in Mediterranean agricultural systems: possible choices in process design (versão Pre Print)

There is an increasing call for local measures to adapt to climate change, based on foresight analyses in collaboration with actors. However, such analyses involve many challenges, particularly because the actors concerned may not consider climate change to be an urgent concern. This paper examines the methodological choices made by three research teams in the design and implementation of participatory foresight analyses to explore agricultural and water management options for adaptation to climate change. Case studies were conducted in coastal areas of France, Morocco, and Portugal where the groundwater is intensively used for irrigation, the aquifers are at risk or are currently overexploited, and a serious agricultural crisis is underway. When designing the participatory processes, the researchers had to address four main issues: whether to avoid or prepare dialogue between actors whose relations may be limited or tense; how to select participants and get them involved; how to facilitate discussion of issues that the actors may not initially consider to be of great concern; and finally, how to design and use scenarios. In each case, most of the invited actors responded and met to discuss and evaluate a series of scenarios. Strategies were discussed at different levels, from farming practices to aquifer management. It was shown that such participatory analyses can be implemented in situations which may initially appear to be unfavourable. This was made possible by the flexibility in the methodological choices, in particular the possibility of framing the climate change issue in a broader agenda for discussion with the actors

Development of the Laser-Two-Focus Method for Non-Intrusive Measurement of Plow Vectors, Particularly in Turbomachines

for a full three-dimensional boundary layer calculation with shock wave interaction. The development of such a complex computational model will require additional laser velocity measurements. These measurements should focus increased attention on the boundary layers and wakes. Data must be acquired on different fans at a variety of operating conditions. Reference

Multi-tier Loyalty Programs to Stimulate Customer Engagement

Customers differ in their purchase behavior, profitability, attitude toward the firm, and so on. These differences between customers have led to numerous firms introducing multi-tier loyalty programs. A multi-tier loyalty program explicitly distinguishes between customers by means of hierarchical tiers (e.g. Silver, Gold, Platinum) and assigns customers to different tiers based on their past purchase behavior. Next, customers in different tiers are provided varying levels of tangible rewards and intangible benefits, which are potentially powerful instruments to stimulate customer engagement. In this chapter, we focus on the design and effectiveness of such multi-tier loyalty programs. Building on loyalty program and customer prioritization research, we discuss whether, why, and how multi-tier loyalty programs are effective (or not) in influencing customer behavior, thereby enhancing customer engagement and financial performance

Structure of nitrilotriacetate monooxygenase component B from Mycobacterium thermoresistibile

The 1.6 Å resolution crystal structure of nitrilotriacetate monooxygenase component B (NTA-MoB) from M. thermoresistibile is presented, revealing a highly conserved C-terminal tail that may modulate the activity of NTA-MoB in mycobacteria

Identification of Chromosomal Genes in Yersinia pestis that Influence Type III Secretion and Delivery of Yops into Target Cells

Pathogenic Yersinia species possess a type III secretion system, which is required for the delivery of effector Yop proteins into target cells during infection. Genes encoding the type III secretion machinery, its substrates, and several regulatory proteins all reside on a 70-Kb virulence plasmid. Genes encoded in the chromosome of yersiniae are thought to play important roles in bacterial perception of host environments and in the coordinated activation of the type III secretion pathway. Here, we investigate the contribution of chromosomal genes to the complex regulatory process controlling type III secretion in Yersinia pestis. Using transposon mutagenesis, we identified five chromosomal genes required for expression or secretion of Yops in laboratory media. Four out of the five chromosomal mutants were defective to various extents at injecting Yops into tissue culture cells. Interestingly, we found one mutant that was not able to secrete in vitro but was fully competent for injecting Yops into host cells, suggesting independent mechanisms for activation of the secretion apparatus. When tested in a mouse model of plague disease, three mutants were avirulent, whereas two strains were severely attenuated. Together these results demonstrate the importance of Y. pestis chromosomal genes in the proper function of type III secretion and in the pathogenesis of plague