A control law for an Integrated Power/Attitude Control System (IPACS) for a satellite is presented in this paper. Four or more energy/momentum wheels in an arbitrary non-coplanar configuration and a set of three thrusters are used to implement the torque inputs. The energy/momentum wheels are used as attitude control actuators, as well as an energy storage mechanism, providing power to the spac...

A wheel is a graph made of a cycle of length at least 4 together with a vertex that has at least three neighbors in the cycle. We prove that the problem whose instance is a graph G and whose question is “does G contains a wheel as an induced subgraph” is NP-complete. We also settle the complexity of several similar problems.

Safety of the wheels for high-speed train was investigated when the tread cleaner, which play a role in the increase of adhesion and the removal of dirt, is failed and stuck in wheel tread. The present study was performed on the basis of analyses of a combination of mechanical and thermal load due to the failure of tread cleaner during severe conditions. The finite element method was used to an...

Automatic guided vehicles with omnidirectional wheels have three degrees of freedom (DOF), their full mobility being obtained by virtue of the free rollers around the periphery of the wheels. The choice of the orientation of the roller axes with respect to the wheel axis, along with the wheel orientations with respect to the platform, the number of wheels, etc., are design issues considered her...

poor stand establishment of canola (brassica napus l.) under flatland mechanized planting and crust-forming soil is a major problem for farmers in central iran. previous research there showed that irrigated cotton emergence on crust-forming soils under flatland planting can be significantly improved using a double-disk planter with zero-pressure press wheel tires and no crust-breaking. in that ...

We enumerate graph homomorphisms to quasi-complete graphs i.e., graphs obtained from complete graphs by removing one edge. The source graphs are complete graphs, quasi-complete graphs, cycles, paths, wheels and broken wheels.