The procedure to find gauge invariant variables for two-parameter nonlinear perturbations in general relativity is considered. Up to third order perturbations, it is shown that appropriate combinations of nonlinear metric perturbations and lower order one are transformed as the gauge transformation of linear order metric perturbations. This implies that gauge invariant variables for the higher ...

recent studies show significant reduction of postural stability in transtibial amputees (ttas) especially when a perturbation is applied. however, no record has been seen on the consequences of such perturbation on the stump-socket interface pressure (ssip). our objective was to investigate whether such perturbation impose excessive pressures on the stump. we were also interested on the type of...

The purpose of this rersearch is to analyze the effective application of particular earth orbits in dynamical modeling of relative motion problem between two spacecraft. One challenge in implementing these motions is maintaining the relations as it experiences orbital perturbations (zonal harmonics J2 and J3), most notably due to the Earth’s oblateness. Certain aspects of the orbital geometry c...