Sexual selection and aerodynamic forces affecting structural properties of the flight feathers of birds are poorly understood. Here, we compared the structural features of the innermost primary wing feather (P1) and the sexually dimorphic outermost (Ta6) and monomorphic second outermost (Ta5) tail feathers of barn swallows (Hirundo rustica) from a Romanian population to investigate how sexual s...

We present results from an independent analysis of friction that more generally addresses all crystalline materials by an extension of coincident site lattice theory and dislocation drag. Calculations for graphitic friction are carried out and agree in magnitude with experimental friction forces. More interestingly, static, dynamic and anisotropic friction forces, incommensurability effects and...

an enhanced displacement feedback structural control procedure is presented for performance-based design in this paper. at first, a comparative study is implemented assessing three most common active control algorithms including state, acceleration, and displacement feedback controls. the advantage of the displacement feedback algorithm for active control of structures against earthquakes is de...

magnetorheological (mr) dampers have the advantage of being tuned by low voltages. this has attracted many researchers to develop semi-active control of structures in theory and practice. most of the control strategies first obtain the desired forces of dampers without taking their dynamics into consideration and then determine the input voltages according to those forces. as a result, these st...