Gas turbine rotor/case structural response to rotating stall: Experimental documentation and analytical approach

The forcing functions and structural responses characterizing gas turbine rotor/case system vibration due to rotating stall in an axial flow compressor are described. Two data sets with fundamentally different response characteristics are presented; one is supersynchronous and the other subsynchronous. Conventional beam element rotor dynamics analysis is shown to be severely limited in its ability to predict these responses. A new analytical approach, which significantly increases structural response predictive capability for these phenomena, is briefly discussed

Mechanism design - A test laboratory viewpoint

Test laboratory methods for determining environmental requirements, cost estimates, and failure possibilities of aerospace system desig

Conceptualizing Student Practice for the 21st Century: Educational and Ethical Considerations in Modernizing the District of Columbia Student Practice Rules

This article traces the history of the amendment process. It provides a short history of student practice rules and then, using the student practice rule in effect in the District of Columbia prior to the 2014 amendments, describes the various components of those rules that courts and bars across the nation have implemented to assist courts, advance legal education, and preserve advocates’ ethical obligations to clients. It then describes some of the comments to the proposed amendments offered by the District of Columbia Bar and other D.C. lawyers during the public comment period and the modifications to the District of Columbia student practice rule that the District of Columbia Court of Appeals accepted. Finally, it discusses some areas of disagreement that arose during the process and a description of the reasons for those disagreements

Synthesis of 4-Thiazolidinone Small Molecules as Potential Inhibitors of the Arp2/3 Complex

Life-essential cellular processes such as endocytosis, motility, and division rely on a cell’s ability to precisely regulate construction of actin filaments in response to external factors and signals. Intrinsically involved in this process is the Actin Related Protein 2/3 (Arp2/3) Complex, a seven-subunit ATPase that functions by nucleating a daughter branch of actin from the side of a pre-existing microfilament. Active Arp2/3 complex is necessary for the proliferation of certain metastatic cancers, and inhibition of Arp2/3 complex is emerging as a potentially useful treatment strategy for such cancers. We describe synthesis and in vitro assays of 4-thiazolidinones predicted by computational methods to inhibit of Arp2/3 Complex strongly, and therefore serve as potential lead compounds for drug development. Known Arp2/3 inhibitor CK-869 serves as the starting point for derivative synthesis. We discuss the efforts towards the synthesis of new compounds and the biochemical data collected about their potency

Graphical workstation capability for reliability modeling

In addition to computational capabilities, software tools for estimating the reliability of fault-tolerant digital computer systems must also provide a means of interfacing with the user. Described here is the new graphical interface capability of the hybrid automated reliability predictor (HARP), a software package that implements advanced reliability modeling techniques. The graphics oriented (GO) module provides the user with a graphical language for modeling system failure modes through the selection of various fault-tree gates, including sequence-dependency gates, or by a Markov chain. By using this graphical input language, a fault tree becomes a convenient notation for describing a system. In accounting for any sequence dependencies, HARP converts the fault-tree notation to a complex stochastic process that is reduced to a Markov chain, which it can then solve for system reliability. The graphics capability is available for use on an IBM-compatible PC, a Sun, and a VAX workstation. The GO module is written in the C programming language and uses the graphical kernal system (GKS) standard for graphics implementation. The PC, VAX, and Sun versions of the HARP GO module are currently in beta-testing stages

Extending Continuum Models for Atom Probe Simulation

This work describes extensions to existing level-set algorithms developed for application within the field of Atom Probe Tomography (APT). We present a new simulation tool for the simulation of 3D tomographic volumes, using advanced level set methods. By combining narrow-band, B-Tree and particle-tracing approaches from level-set methods, we demonstrate a practical tool for simulating shape changes to APT samples under applied electrostatic fields, in three dimensions. This work builds upon our previous studies by allowing for non-axially symmetric solutions, with minimal loss in computational speed, whilst retaining numerical accuracy

Timing of poverty in childhood and adolescent health: Evidence from the US and UK

Childhood poverty is associated with poorer adolescent health and health behaviours, but the importance of the timing of poverty remains unclear. There may be critical or sensitive periods in early life or early adolescence, or poverty may have cumulative effects throughout childhood. Understanding when poverty is most important can support efficient timing of interventions to raise family income or buffer against the effects of low income, but answers may vary across social contexts. The US and the UK are a useful comparison with similar liberal approaches to cash transfers, but very different approaches to healthcare provision. Utilising data from large population studies in the US (n = 9408; born 1979–1996) and UK (n = 1204; born 1991–1997), this study employs a structured life course approach to compare competing hypotheses about the importance of the timing or pattern of childhood exposure to poverty in predicting adolescent health limitations, symptoms of psychiatric distress, and smoking at age 16 (age 15/16 in US). Household income histories identified experience of poverty (measured as <60% of the national median equivalised income for a given year) in early life (ages 0–5), mid-childhood (ages 6–10) and early adolescence (ages 11–15). The Bayesian Information Criterion (BIC) compared fit across models with variables representing different life course patterns of exposure to poverty. Adolescent distress was not associated with poverty in either country. In both countries, however, variables representing cumulative or persistent experiences of poverty exhibited optimal fit of all poverty exposure variables in predicting adolescent smoking and health limitations. There was also evidence of an early life sensitive period for smoking in the US. Poverty was more persistent in the US, but associations between poverty and outcomes were consistent across countries. Although poverty can have cumulative effects on health and behaviour, early interventions may offer the best long-term protection

Quantitative microscopy of the Drosophila ovary shows multiple niche signals specify progenitor cell fate.

Adult stem cells commonly give rise to transit-amplifying progenitors, whose progeny differentiate into distinct cell types. It is unclear if stem cell niche signals coordinate fate decisions within the progenitor pool. Here we use quantitative analysis of Wnt, Hh, and Notch signalling reporters and the cell fate markers Eyes Absent (Eya) and Castor (Cas) to study the effects of hyper-activation and loss of niche signals on progenitor development in the Drosophila ovary. Follicle stem cell (FSC) progeny adopt distinct polar, stalk, and main body cell fates. We show that Wnt signalling transiently inhibits expression of the main body cell fate determinant Eya, and Wnt hyperactivity strongly biases cells towards polar and stalk fates. Hh signalling independently controls the proliferation to differentiation transition. Notch is permissive but not instructive for differentiation of multiple cell types. These findings reveal that multiple niche signals coordinate cell fates and differentiation of progenitor cells

Wheat Cleaning and its Effect on U.S. Wheat Exports

This analysis shows that there could be net gains to the U.S. wheat industry if all U.S. export wheat were to be cleaned to a dockage level between 0.35 to 0.40 percent. These results are based on survey results of major importers of U.S. wheat, and a model of world wheat trade. Larger benefits to the U.S. wheat industry would be possible from cleaning only wheat destined to countries that demand higher quality U.S. wheat. However, these gains in export revenue from selling cleaner wheat could be offset if other exporters, especially Canada, responded in ways that would maintain their market share.wheat, grain quality, trade model, Crop Production/Industries, International Relations/Trade,

Rational Russia: Decision-Making in a Declining Superpower

Russia’s 2008 invasion of Georgia demonstrates that Putin’s state still behaves rationally