Impact dynamics research facility for full-scale aircraft crash testing

An impact dynamics research facility (IDRF) was developed to crash test full-scale general aviation aircraft under free-flight test conditions. The aircraft are crashed into the impact surface as free bodies; a pendulum swing method is used to obtain desired flight paths and velocities. Flight paths up to -60 deg and aircraft velocities along the flight paths up to about 27.0 m/s can be obtained with a combination of swing-cable lengths and release heights made available by a large gantry. Seven twin engine, 2721-kg aircraft were successfully crash tested at the facility, and all systems functioned properly. Acquisition of data from signals generated by accelerometers on board the aircraft and from external and onboard camera coverage was successful in spite of the amount of damage which occurred during each crash. Test parameters at the IDRF are controllable with flight path angles accurate within 8 percent, aircraft velocity accurate within 6 percent, pitch angles accurate to 4.25 deg, and roll and yaw angles acceptable under wind velocities up to 4.5 m/s

Crash tests of four identical high-wing single-engine airplanes

Four identical four place, high wing, single engine airplane specimens with nominal masses of 1043 kg were crash tested at the Langley Impact Dynamics Research Facility under controlled free flight conditions. These tests were conducted with nominal velocities of 25 m/sec along the flight path angles, ground contact pitch angles, and roll angles. Three of the airplane specimens were crashed on a concrete surface; one was crashed on soil. Crash tests revealed that on a hard landing, the main landing gear absorbed about twice the energy for which the gear was designed but sprang back, tending to tip the airplane up to its nose. On concrete surfaces, the airplane impacted and remained in the impact attitude. On soil, the airplane flipped over on its back. The crash impact on the nose of the airplane, whether on soil or concrete, caused massive structural crushing of the forward fuselage. The liveable volume was maintained in both the hard landing and the nose down specimens but was not maintained in the roll impact and nose down on soil specimens

Should the FDIC worry about the FHLB? the impact of Federal Home Loan Bank advances on the Bank Insurance Fund

Does growing commercial-bank reliance on Federal Home Loan Bank (FHLBank) advances increase expected losses to the Bank Insurance Fund (BIF)? Our approach to this question begins by modeling the link between advances and expected losses. We then quantify the effect of advances on default probability with a CAMELS-downgrade model. Finally, we assess the impact on loss-given-default by estimating resolution costs in two scenarios: the liquidation of all banks with failure probabilities above two percent and the liquidation of all banks with advance-to-asset ratios above 15 percent. The evidence points to non-trivial increases in expected losses. The policy implication is that the FDIC should price FHLBank-related exposures.Banks and banking ; Financial institutions ; Deposit insurance

Keyword enhanced web structure mining for business intelligence

The study proposed the method of keyword enhanced Web structure mining which combines the ideas of Web content mining with Web structure mining. The method was used to mine data on business competition among a group of DSLAM companies. Specifically, the keyword DSLAM was incorporated into queries that searched for co-links between pairs of company Websites. The resulting co-link matrix was analyzed using multidimensional scaling (MDS) to map business competition positions. The study shows that the proposed method improves upon the previous method of Web structure mining alone by producing a more accurate map of business competition in the DSLAM sector. ©Springer-Verlag Berlin Heidelberg 2009

Exploring reflective design: an approach to digital archives

In this short paper we discuss our explorations with adopting reflective design as an approach to designing a digital archive for the performing arts. The stakeholders in this project are diverse, comprised of members of the partner organisation, the public, the design team and government funding agencies. Each stakeholder has different expectations and skills to bring to the project. It is proposed that reflective design with its mix of critical reflection with a human centred design and prototyping approach provides a methodological framework that enables the complexities of the project to be integrated into an action orientated design exploration

Sums of two squares and a power

We extend results of Jagy and Kaplansky and the present authors and show that for all $k\geq 3$ there are infinitely many positive integers $n$, which cannot be written as $x^2+y^2+z^k=n$ for positive integers $x,y,z$, where for $k\not\equiv 0 \bmod 4$ a congruence condition is imposed on $z$. These examples are of interest as there is no congruence obstruction itself for the representation of these $n$. This way we provide a new family of counterexamples to the Hasse principle or strong approximation.Comment: 6 pages, to appear in the memorial volume "From Arithmetic to Zeta-Functions - Number Theory in Memory of Wolfgang Schwarz

Cars, conflict and community severance

Livable Streets 2.0 offers a thorough examination of the struggle between automobiles, residents, pedestrians and other users of streets, along with evidence-based, practical strategies for redesigning city street networks that support urban livability. In 1981, when Donald Appleyard’s Livable Streets was published, it was globally recognized as a groundbreaking work, one of the most influential urban design books of its time. Unfortunately, he was killed a year later by a speeding drunk driver. This latest update, Livable Streets 2.0, revisited by his son Bruce, updates on the topic with the latest research, new case studies and best practices for creating more livable streets. It is essential reading for those who influence future directions in city and transportation planning

Affinity and ambiguity in designerly leadership

This paper discusses a new theory of Designerly Leadership in response to major disruptions in the ways that products and services are designed, made, and distributed. We outline an experientially derived framing of what it means to lead in a designerly fashion, particularly focusing on how leaders modulate their perceptions of affinity and develop extended methods for working with ambiguity. We then propose a series of ways that programs wanting to educate design managers for strategic roles could build and support this capacity in their graduates