Abstract: A discrete element method contact model building method includes: selecting a filling body in a disaster-causing structure to obtain a change rule of cumulative loss of the filling body; performing test simulation, and determining a relation function of each group of corresponding mesoscopic mechanical parameters in each time period and mesoscopic parameters of a DEM contact model representing a change rule of macroscopical parameters of the filling body; embedding each mesoscopic parameter relation function into an existing particle contact model, performing test simulation, and updating a fracture failure criterion of the contact model according to a corresponding relation of macro-mesoscopic strength during model failure; and based on a seepage failure indoor test, building a seepage failure discrete element calculation model, and simulating the seepage failure process of a rock and soil mass by using the obtained particle contact model and the fracture criterion of the particle contact model.

Abstract: A device for deterring a dog from barking includes a sensor for detecting a bark from a dog and for generating an activation signal upon detection of the bark and an integral housing. The integral housing includes a reservoir for storing a bark deterrent substance, a bobbin integrated with the reservoir, a wall separating the bobbin from the reservoir, and an aperture extending through the wall for allowing fluid communication between the reservoir and the bobbin. The device further includes a spray mechanism for delivery of a dose of the bark deterrent substance to the dog upon receipt of the activation signal from the sensor.