Characteristics of unsteady total pressure distortion for a complex aero-engine intake duct

Some types of aero-engine intake systems are susceptible to the generation of secondary flows with high levels of total pressure fluctuations. The resulting peak distortion events may exceed the tolerance level of a given engine, leading to handling problems or to compressor surge. Previous work used distortion descriptors for the assessment of intake-engine compatibility to characterise modestly curved intakes where most of the self-generated time-dependent distortion was typically found to be dominated by stochastic events. This work investigates the time-dependent total pressure distortion at the exit of two high off-set diffusing S-duct intakes with the aim of establishing whether this classical approach, or similar, could be applied in these instances. The assessment of joint probability maps for time dependent radial and circumferential distortion metrics demonstrated that local ring-based distortion descriptors are more appropriate to characterise peak events. Extreme Value Theory (EVT) was applied to predict the peak distortion levels that could occur for a test time beyond the experimental data set available. Systematic assessments of model sensitivities to the de-clustering frequency, the number of exceedances and sample time length were used to extend the EVT application to local distortion descriptors and to provide guidelines on its usage

Shooting \u3cem\u3eHeller\u3c/em\u3e in the Foot?: Applying and Misapplying \u3cem\u3eDistrict of Columbia v. Heller\u3c/em\u3e\u27s Presumptively Lawful Dicta in \u3cem\u3eUnited States v. Skoien\u3c/em\u3e

On July 13, 2010, an en banc panel of the U.S. Court of Appeals for the Seventh Circuit in United States v. Skoien upheld 18 U.S.C. § 922(g)(9), a federal ban on the possession of firearms by domestic violence misdemeanants, against a Second Amendment challenge. In reaching its holding, the Seventh Circuit declined to follow either of two analytical frameworks that lower courts have applied to Second Amendment challenges since the U.S. Supreme Court’s groundbreaking 2008 ruling in District of Columbia v. Heller. This Comment argues that, although the Skoien en banc opinion ignores an important piece of the Heller Court’s dicta, its analysis is generally faithful to Heller and should serve as a model for other courts of appeals until the Supreme Court provides additional guidance