Sustained load crack growth design data for Ti-6Al-4V titanium alloy tanks containing hydrazine

Sustained load crack growth data for Ti-6Al-4V titanium alloy in hydrazine per MIL-P-26536 and refined hydrazine are presented. Fracture mechanics data on crack growth thresholds for heat-treated forgings, aged and unaged welds, and aged and unaged heat-affected zones are reported. Fracture mechanics design curves of crack growth threshold stress intensity versus temperature are generated from 40 to 71 C

The simulation of coherent structures in a laminar boundary layer

Coherent structures in turbulent shear flows were studied extensively by several techniques, including the VITA technique which selects rapidly accelerating or decelerating regions in the flow. The evolution of a localized disturbance in a laminar boundary layer shows strong similarity to the evolution of coherent structures in a turbulent-wall bounded flow. Starting from a liftup-sweep motion, a strong shear layer develops which shares many of the features seen in conditionally-sampled turbulent velocity fields. The structure of the shear layer, Reynolds stress distribution, and wall pressure footprint are qualitatively the same, indicating that the dynamics responsible for the structure's evolution are simple mechanisms dependent only on the presence of a high mean shear and a wall and independent of the effects of local random fluctuations and outer flow effects. As the disturbance progressed, the development of streak-like-high- and low-speed regions associated with the three-dimensionality

An investigation of children's peer trust across culture: is the composition of peer trust universal?

The components of children's trust in same-gender peers (trust beliefs, ascribed trustworthiness, and dyadic reciprocal trust) were examined in samples of 8- to 11-year-olds from the UK, Italy, and Japan. Trust was assessed by children's ratings of the extent to which same-gender classmates kept promises and kept secrets. Social relations analyses confirmed that children from each country showed significant: (a) actor variance demonstrating reliable individual differences in trust beliefs, (b) partner variance demonstrating reliable individual differences in ascribed trustworthiness, and (c ) relationship variance demonstrating unique relationships between interaction partners. Cultural differences in trust beliefs and ascribed trustworthiness also emerged and these differences were attributed to the tendency for children from cultures that value societal goals to share personal information with the peer group

Symbiotic stars: the geometry of the radio emitting regions

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Validating performance of automotive materials at high strain rate for improved crash design

This paper investigates sources of performance variability in high velocity testing of automotive crash structures. Sources of variability, or so called noise factors, present in a testing environment, arise from uncertainty in structural properties, joints, boundary conditions and measurement system. A box structure, which is representative of a crash component, is designed and fabricated from a high strength Dual Phase sheet steel. Crush tests are conducted at low and high speed. Such tests intend to validate a component model and material strain rate sensitivity data determined from high speed tensile testing. To support experimental investigations, stochastic modeling is used to investigate the effect of noise factors on crash structure performance variability, and to identify suitable performance measures to validate a component model and material strain rate sensitivity data. The results of the project will enable the measurement of more reliable strain rate sensitivity data for improved crashworthiness predictions of automotive structures

Intelligent and adaptive tutoring for active learning and training environments

Active learning facilitated through interactive and adaptive learning environments differs substantially from traditional instructor-oriented, classroom-based teaching. We present a Web-based e-learning environment that integrates knowledge learning and skills training. How these tools are used most effectively is still an open question. We propose knowledge-level interaction and adaptive feedback and guidance as central features. We discuss these features and evaluate the effectiveness of this Web-based environment, focusing on different aspects of learning behaviour and tool usage. Motivation, acceptance of the approach, learning organisation and actual tool usage are aspects of behaviour that require different evaluation techniques to be used

The relationship between neutralizations and perceived delinquent labeling on criminal history in young offenders serving community orders

This study examined the associations between young offenders’ justifications for delinquent behavior, their perceptions of being labeled “delinquent,” and criminal history. Participants were 153 young offenders (aged 14 to 19 years) serving community orders with the New South Wales Department of Juvenile Justice, Australia. They completed a questionnaire that assessed their use of justifications for offending (neutralizations) and their perceptions of being delinquent. More than half of young offenders (53.6%) did not believe that others labeled them as “delinquent”. Those who did believe that others labeled them as “delinquent” (28.8%) self-reported more delinquency and other problem behaviors, but did not a have more serious official criminal history than ‘unlabeled’ offenders. Factor analysis revealed a two-factor structure (minimization and rationalization) for the neutralization items. Neutralization factors were weak predictors of official criminal history, but stronger predictors of self-reported delinquency and other problem behaviors. Age at first court appearance and rationalizations successfully discriminated 66.7% of the young offenders who thought others labeled them as “delinquents”. Findings are discussed with reference to the implications for risk and responsivity principles in the treatment of young offenders

An examination of ethical standards and behaviors in transportation brokerage

The manuscript examines individual ethical decision making for common scenarios faced by transportation brokers, including unauthorized double brokering, booking and bouncing, and a failure to disclose all terms to a shipper. The results indicate significant discrepancies between what actions a broker would engage, what brokers perceive that others in the same industry would do, and what industry leaders perceive to be ethical

Electron tunnel sensor technology

Researchers designed and constructed a novel electron tunnel sensor which takes advantage of the mechanical properties of micro-machined silicon. For the first time, electrostatic forces are used to control the tunnel electrode separation, thereby avoiding the thermal drift and noise problems associated with piezoelectric actuators. The entire structure is composed of micro-machined silicon single crystals, including a folded cantilever spring and a tip. The application of this sensor to the development of a sensitive accelerometer is described