Water-hammer is a transient condition which may occur in a network as a result of rapid or slow valve closures, pump failures, changes in turbine loading, etc. It creates high and low pressure waves which travel along the system and decay as a result of wall shear stress. Comparison o experimental and theoretical results revealed the failure of steady or quasi-steady models in correctly predict...

One of the great enemies of rubber compounds is heat. Heat will cause chemical and physical degradation of vulcanized rubber as well as a considerable loss in its strength. A major source of heat generation in a tire is due to internal friction resulting from the viscoelastic deformation of the tire as it rolls along the road. Another source of heat generation in a tire is due to its contact fr...

By using analytical correlations derived as a result of theoretical research, a computer algorithm has been worked out for simulating the functions of the plough body and the forces exerted by soil upon the operating parts, as well as its draft resistance. These correlations allow to determine the draft resistance of the plough depending on the parameters of its body, as well as to evaluate the...

It is shown that for any elastic string model with energy density U and tension T , the divergent contribution from gravitational self interaction can be allowed for by an action renormalisation proportional to (U − T ). This formula is applied to the important special case of a bare model of the transonic type (characterised by a constant value of the product UT ) that represents the macroscop...

This paper presents the results of a laboratory investigation to determine the geotechnical properties of fresh municipal solid waste (MSW) collected from the working phase of Orchard Hills Landfill located in Davis Junction (Illinois, USA). Laboratory testing was conducted on shredded MSW to determine the compaction, hydraulic conductivity, compressibility, and shear strength properties at in-...

A new insight into the mechanics of belt friction is given. A conceptual and methodological drawback in the presentation of the classical derivation of the force required to pull the belt over a fixed drum against the hold-force and the friction between the belt and a drum is pointed out, corrected and discussed. The total forces due to pressure and friction (P and F ) are evaluated in magnitud...

is interpreted as the number of particles occupying at time t ≥ 0, a position x in the set Ω, and having their velocity v in the set V . The fluid is described through its velocity field u(t, x) ∈ R . Forces exerted on the particles are supposed to reduce to the friction forces exerted by the surrounding fluid. They are supposed to be proportional to the relative velocity (u − v): the so-called...

We have examined by molecular dynamics simulations the friction which arises when two hydrogen-te~inated diamond (111) surfaces are placed in sliding contact. In particular, the effects of load, crystallographic sliding direction, and substitution of surface hydrogen groups by methyl groups on the friction coefkient p were investigated. For the hydrogen-terminated system, it is possible to have...

Nowadays there is an increased need to know the nanotribological properties of protective coatings used in part devices operating under nanoand micro-contact situations, e.g. hard disk drives, magnetic heads, micro-electromechanical systems (MEMS) and microsensors, etc. Therefore there is a demand for instruments and methods testing friction and wear at the nanoand micro-scales. In this work we...

The friction and load variation are the main uncertainties in the linear piezoelectric motor system. Only the viscous friction is considered in previous work, but it is quite different with the practical condition. Highly nonlinear friction in the system is measured and compensated by a radial basis function (RBF) network. A discrete-time sliding mode controller, which is insensitive to the per...