Frictional Phenomena in Dynamical Systemwith Two-Frequency Excitation

The paper deals with investigation of a self-excited vibrating system with dry friction. The system is composed of a mass connected by viscoelastic element with the referring frame and interacting with a moving belt by means of dry friction. An experimentally identified, multi-parametric dry friction model for the pair composed of soft and hard elements like steel–polyester pair, describing both the case of stick-slip and quasi-harmonic vibration, has been applied. Additionally, the system is influenced by external, two-frequency kinematic excitation. The results of computer simulation for different excitation conditions are submitted in the present paper.     

Trichloroethylene in organic synthesis: II. reaction of trichloroethylene with secondary amines

In a novel reaction, trichloroethylene reacts with secondary aliphatic amines in the presence of aqueous solution of NaOH and catalytic quantity of benzyltriethylammonium chloride to give the corresponding N,N,N,'N'-tetraalkylsubstituted glycinamides. The following glycinamides were obtained with high yield: /N-morpholine/acetic acid morpholide, N-/piperidineacetyl/piperidine, N,N,N,'N'-tetra-n-butylglycinamide and N,N,N,'N'-tetraethlyglycinamide. Mechanism of the reaction is discussed.