In this study part of the mitochondrial D-loop was sequenced in a total of 40 samples from nine Swedish local chicken breeds. Among our 40 samples we observed 15 segregating sites and seven different haplotypes. The most common haplotype was present in all investigated individuals in five breeds and together with other haplotypes in three breeds. This haplotype is common in domestic chickens and has been found in both local and commercial breeds in many parts of the world. The breed Ölandshöna was most different from the other Swedish breeds with all three individuals sharing a haplotype that differed from the most common haplotype at nine of the 15 segregating sites.

No abstract

Most modern cars have a bellows-type flexible joint between the manifold and the catalytic converter to allow for thermal expansion and to decouple large engine movements and vibrations from the rest of the exhaust system. To obtain better understanding of the influence of this joint, the dynamic response of a typical exhaust system is studied when excited via different joint configurations. Measurements show the great order of reduction in vibration transmission to the exhaust system that a bellows joint, with and without an inside liner, gives in comparison with a stiff joint. For the combined bellows and liner joint, vibration transmission is, however, higher than for the bellows alone. Together with some other aspects this makes the choice of including a liner in the exhaust system application complex. For a system in general the possibility of tuning the friction limit of the liner, to minimize overall vibrations through friction-based damping, depends on how close to ideal the excitation source is and its location. Anyhow, the combined bellows and liner joint makes the exhaust system behaviour significantly non-linear, whereas the system behaviour proves to be essentially linear when the bellows has no liner, which imply that the liner needs to be included in theoretical models when present in the real system.

A bellows combined with an inside liner and an outside braid is commonly used as a flexible joint in automobile exhaust systems to reduce transmission of engine movements to the exhaust system. It greatly influences the dynamics of the complete system. Understanding of its dynamic characteristics and a modelling method that facilitates systems simulation are therefore desired. This has been obtained in earlier works for the bellows itself. In this work an approach to the modelling of the combined bellows and liner joint is suggested and experimentally verified. Simulations and measurements show that the liner adds significant non-linearity and makes the characteristics of the joint complex. Results are presented for the axial and the bending load cases. In torsion, influence of the liner is negligible. Peak responses are significantly reduced when the excitation level approximately corresponds to the friction limit of the liner. The complexity of the combined bellows and liner joint is important to know of and consider in exhaust system design and proves the necessity of including a model of the liner in the theoretical joint model when this type of liner is present in the real joint to be simulated.