Statistical and spectral analyses of the manipulation of a canonical zero pressure gradient turbulent boundary layer using static roughness and low-frequency dynamic roughness patches are presented. A shift of spectral energy away from the wall downstream of the roughness patch is observed. The dynamic roughness is shown to disrupt the structure of the boundary layer, while embedding its period...

We present a method to suppress the roughness of the potential of a wire-based, magnetic atom guide: modulating the wire current at a few tens of kHz, the potential roughness, which is proportional to the wire current, averages to zero. Using ultracold 87Rb clouds, we show experimentally that modulation reduces the roughness by at least a factor five without measurable heating or atom loss. Thi...

In machining of parts, surface quality is one of the most specified customer requirements. Major indication of surface quality on machined parts is surface roughness. Finish hard turning using Cubic Boron Nitride (CBN) tools allows manufacturers to simplify their processes and still achieve the desired surface roughness. There are various machining parameters have an effect on the surface rough...

Zinc Aluminum Oxide (ZAO) thin films were deposited on glass substrates by DC reactive magnetron sputtering technique with high purity Zn and Al targets. After the deposition, the films were annealed in vacuum from 200 to 500 C. Surface roughness measurement of ZAO thin films in the nanometer scale can be accurately determined using the atomic force microscopy. Surface roughness and grain size ...

The properties of CsK2Sb, make this material an ideal candidate as photocathode for electron injector use. Producing photocathodes with quantum efficiencies of 5 % and greater at 532 nm poses no challenge, nevertheless the traditional growth mechanisms, which are based on a sequential deposition of Antimony, Potassium and Cesium at a range of temperatures up to 150◦C yield a rough surface with ...

In this study, the effect of the substrate roughness on adhesion of mushroom-shaped microstructure was experimentally investigated. To do so, 12 substrates having different isotropic roughness were prepared from the same material by replicating topography of different surfaces. The pull-off forces generated by mushroom-shaped microstructure in contact with the tested substrates were measured an...

Hydrodynamic river models are applied to design and evaluate measures for purposes such as safety against flooding. The modeling of river processes involves numerous uncertainties, resulting in uncertain model results. Knowledge of the type and magnitude of these uncertainties is crucial for a meaningful interpretation of the model results. The aim of this study is to quantify the uncertainty d...

Introduction: Air-powder polishing devices are increasingly used for stain and plaque removal. However, besides cleaning the tooth surface, they may increase the surface roughness of the dental tissues. This in turn may result in plaque accumulation and superficial degradation. Thus the aim of this study was to assess the influence of three different abrasive agents: Pumice, Sodium bicarbonate ...

The aim of this study was, for the first time, to measure and compare quantitatively the viscoelastic properties and surface roughness of coronary arteries. Porcine left anterior descending coronary arteries were dissected ex vivo. Viscoelastic properties were measured longitudinally using dynamic mechanical analysis, for a range of frequencies from 0.5 to 10 Hz. Surface roughness was calculate...

Surface roughness is considered as one of the most specified customer requirements in machining processes. For efficient use of machine tools, selection of machining process and determination of optimal cutting parameters (speed, feed and depth of cut) are required. Therefore, it is necessary to find a suitable way to select and to find optimal machining process and cutting parameters for a spe...