Additional measurements of the drag of surface irregularities in turbulent boundary layers

In connection with earlier measurements by K. Wieghardt the increase of the turbulent friction drag was determined for some additional types of common surface irregularities

On the turbulent friction layer for rising pressure

Among the information presented are included displacement, momentum, and kinetic energy thicknesses, shearing stress distributions across boundary layer, and surface friction coefficients. The Gruschwitz method and its modifications are examined and tested. An energy theorem for the turbulent boundary layer is introduced and discussed but does not lead to a method for the prediction of the behavior of the turbulent boundary layer because relations for the shearing stress and the surface friction are lacking

Investigations of the wall-shearing stress in turbulent boundary layers

Because of the unsatisfactory state of knowledge concerning the surface shearing stress of boundary layers with pressure gradients, the problem is re-examined. It is found that for general turbulent boundary layers in wall proximity, that is, in the laminar sublayer, in the transition zone and in the part of the completely turbulent zone near the wall, the same universal law applies as for the plate flow

Оценка времени на прогнозирование технического состояния средств аппаратного контроля

Предлагается метод повышения достоверности функционирования ЭВМ АСУ в условиях воздействия мощных электромагнитных помех (МЭМП), приводятся оценки допустимого времени на прогнозирование технического состояния средств аппаратного контроля (АК) после воздействия мощных электромагнитных помех

Tribological Characteristics of Tungsten Carbide Reinforced Arc Sprayed Coatings using Different Carbide Grain Size Fractions

Tungsten carbide reinforced coatings play an important role in the field of surface engineering to protect stressed surfaces against wear. For thermally sprayed coatings, it is already shown that the tribological properties get mainly determined by the carbide grain size fraction. Within the scope of this study, the tribological characteristics of iron based WC-W2C reinforced arc sprayed coatings deposited using cored wires consisting of different carbide grain size fractions were examined. Microstructural characteristics of the produced coatings were scrutinized using electron microscopy and x-ray diffraction analyses. Ball-on-disk test as well as Taber Abraser and dry sand rubber wheel test were employed to analyze both the dry sliding and the abrasive wear behavior. It was shown that a reduced carbide grain size fraction as filling leads to an enhanced wear resistance against sliding. In terms of the Taber Abraser test, it is also demonstrated that a fine carbide grain size fraction results in an improved wear resistant against abrasion. As opposed to that, a poorer wear resistance was found within the dry sand rubber wheel tests. The findings show that the operating mechanisms for both abrasion tests affect the stressed surface in a different way, leading either to microcutting or microploughing

THE URGE TO CHECK SOCIAL NETWORKING SITES: ANTECEDENTS AND CONSEQUENCES

Social networking sites (SNSs), combined with the rapid growth trajectory of mobile devices, and widespread deployment of mobile data services, have evolved as a primary platform for daily social interaction. While the majority of users enjoy frequent interactions with their friends and family members, some users suffer from incessant urges to check up on the lives of others on their social networks. In the last decade, the use of SNSs has received much attention in the IS literature. Not until recently, researchers have begun to examine the dark side of using SNSs. In this study, we attempt to advance existing literature by exploring the role of urges in the context of SNSs. Particularly, we propose a research model that examines the antecedents and consequences of the urge to check SNSs. We will test the model with SNS users using structural equation modeling. We believe that current work will enrich the existing literature on the dark side of SNS use, and raise the awareness in the community regarding this emerging phenomenon

Archimedean spiral and its implication in the world around us

Spiral form combines symmetry and the golden ratio, with visual perception, it causes a feeling of harmony. The basis of many forms of beauty created by nature, is a spiral. This article discusses types of coils - from the simplest to the most complex, are found in the world around us

Automatic estimation of harmonic tension by distributed representation of chords

The buildup and release of a sense of tension is one of the most essential aspects of the process of listening to music. A veridical computational model of perceived musical tension would be an important ingredient for many music informatics applications. The present paper presents a new approach to modelling harmonic tension based on a distributed representation of chords. The starting hypothesis is that harmonic tension as perceived by human listeners is related, among other things, to the expectedness of harmonic units (chords) in their local harmonic context. We train a word2vec-type neural network to learn a vector space that captures contextual similarity and expectedness, and define a quantitative measure of harmonic tension on top of this. To assess the veridicality of the model, we compare its outputs on a number of well-defined chord classes and cadential contexts to results from pertinent empirical studies in music psychology. Statistical analysis shows that the model's predictions conform very well with empirical evidence obtained from human listeners.Comment: 12 pages, 4 figures. To appear in Proceedings of the 13th International Symposium on Computer Music Multidisciplinary Research (CMMR), Porto, Portuga