A constitutive model based on plasticity theory with a non-associative flow rule has been developed. The model is formulated in terms of sleeper displacements and forces, and includes hardening and softening controlled by irreversible transversal (lateral and longitudinal) sleeper displacements. The model has been calibrated using results from lateral and longitudinal ballast resistance tests c...

A novel concept of polymer railway sleeper is proposed in this study that has the potential to meet static performance requirements within cost hardwood timber. The existing challenges composite sleepers, such as low or high cost, can be overcome using innovative concept. Such a proclamation proven through limit state design criteria and series experimentations. Results show polyurethane foam a...

in this research, the structural behavior of timber and concrete sleepers in a standard railway turnout is evaluated, in the case of raising speed. in approaching this evaluation, current practices in the structural analysis of sleepers are surveyed and then, the sensitivity analysis with abaqus software is made based on selected criteria (bending and shear stresses as well as contact pressure)...

The objective of this study was to describe sleep patterns in patients with heart failure (HF) and analyze associations between sleep and the following variables: gender, age, fatigue, fatigue on exertion, physical activity, functional class, drug therapy, dyspnea, and body mass index. The nonprobability sample consisted of 400 patients (mean age 57.8 years; 64.8% were men, average schooling of...

Problem: Infer relative danger from spatially segregated predators in large-scale marine systems, using individual differences in prey foraging behaviour. Mathematical models: Optimization of trade-offs between predation risk and energy gain. Key assumption: Foraging individuals choosing to incur higher risk of predation should experience higher energetic gain than individuals choosing safer fo...

Why do some individuals need more sleep than others? Forward mutagenesis screens in flies using engineered mutations have established a clear genetic component to sleep duration, revealing mutants that convey very long or short sleep. Whether such extreme long or short sleep could exist in natural populations was unknown. We applied artificial selection for high and low night sleep duration to ...

(U) The relationship between perceived sleep quality and career effectiveness was studied in Navy corpsmen. Two samples of Naval School of Health Sciences students were asked, "Overall, what kind of sleeper are you?" Based on responses, 506 "good" sleepers and 109 "poor" sleepers were selected for longitudinal study and followed for 6 years. For replication. Sample 2, consisting of 1,024 good a...

The egg development and early life history of Korean spotted sleeper, Odontobutis interrupta which is Korean endemic species from Sora-choen was investigated. The Korean spotted sleeper were caught at Sora-myeon, Yeosu-si, Jeollanamdo, from Korea at May in 2014. The fertilized eggs were 4.23 ± 0.05 mm in long diameter and had oil globules. Hatching time of the embryo began about 442 hr 14 min a...