The paper presents near-wall scaling in incompressible and compressible flows. It concentrates on flows with streamwise pressure gradients which render traditional scaling inapplicable. For incompressible flows a scaling for the velocity profiles is introduced based on both the friction velocity and the pressure gradient. For compressible flows a scaling is developed for the velocity and the te...

We have applied both the master equation method and harmonic transition state theory to interpret the velocity-dependent friction behavior observed in atomic friction experiments. To understand the discrepancy between attempt frequencies measured in atomic force microscopy experiments and those estimated by theoretical models, both thermal noise and instrumental noise are introduced into the mo...

Inverse analysis is a method for determining material parameters by minimizing the difference between experimental and the finite element (FE) simulated results, such as the load-stroke curve and barreling shape of a deformed specimen using an optimum design technique. In this study, ring compression tests were conducted to predict the flow stress of materials and interfacial friction condition...

The failure reasons of reciprocating sealing in OPI-1800AWS fracturing pump are analyzed by scanning electron microscope technology (SEMT). The lubrication mechanism of plunger seal friction pair is analyzed by hydrodynamic lubrication theory. During its discharge and suction stroke, the reciprocating sealing friction pair meets the conditions of hydrodynamic lubrication, a certain thickness of...

Effective predictors of Intensive Care Unit (ICU) Mortality have the potential to identify high-risk patients earlier, improve ICU resource allocation, and create more accurate population-level risk models. Machine learning practitioners typically make choices about how to represent features in a particular model, but these choices are seldom evaluated quantitatively. This study compares the pe...

We develop and test a ‘‘slip-based’’ method to estimate the maximum available tire-road friction during braking. The method is based on the hypothesis that the low-slip, low-m parts of the slip curve used during normal driving can indicate the maximum tire-road friction coefficient, mmax . We find support for this hypothesis in the literature and through experiments. The friction estimation alg...

With the discovery of Kuiper Belt binaries that have wide separations and roughly equal masses new theories were proposed to explain their formation. Two formation scenarios were suggested by Goldreich and collaborators: In the first, dynamical friction that is generated by the sea of small bodies enables a transient binary to become bound (Ls mechanism); in the second, a transient binary gets ...

Horizontal and vertical advective fluxes of CO2 measured during the CarboEurope-IP advection experiment (ADVEX) at the Wetzstein spruce forest site in Thuringia, Germany, were related to wind direction, stratification regime and friction velocity u*. Measurements of wind speed and direction carried out at one of the slopes of the ridge revealed the existence of reverse flow below the canopy on ...

This work presents a novel gait generation method for biped hopping with point feet. The investigated biped model consists of a kneed massless leg and a trunk with two Hill-type muscles at the hip and knee joints. The dynamic equations of the system are derived using Lagrange method. Since the most important phase to stabilize bipedal running and hopping motion is stance phase, this paper deals...

In this paper, we study theoretically and experimentally the friction between a rough parabolic or conical profile and a flat elastomer beyond the validity region of Amontons' law. The roughness is assumed to be randomly self-affine with a Hurst exponent H in the range from 0 to 1. We first consider a simple Kelvin body and then generalize the results to media with arbitrary linear rheology. Th...