479 research outputs found

    Numerical analysis of the influence of liquid on propagation of a rolling contact fatigue crack

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    Numerical investigations of the propagation of rolling contact fatigue crack filled by the liquid have been conducted. Two models of fluid – crack interaction have been considered. In the first model called “hydrostatic” the assumption of incompressible, inviscid and weightless liquid was accepted. It was also assumed that due to the wheel load the trapped liquid could not get outside the crack and its volume remained constant until the rising pressure would open up the crack mouth again. On this assumption the analysis has a steady-state character. In the second model it has been assumed that the crack is filled by the viscous, incompressible fluid and the fluid motion as well as the resulting pressure distribution can be represented by one-dimensional form of the Reynolds equation. The method for solving the problem of the coupled motion of liquid and crack faces has been developed and series of calculation were made. The method has been employed for the predicting of crack deformation in the course of wheel rolling

    Extreme right-wing voting in Western Europe

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    In this study we explain extreme right-wing voting behaviour in the countries of the European Union and Norway from a micro and macro perspective. Using a multidisciplinary multilevel approach, we take into account individual-level social background characteristics and public opinion alongside country characteristics and characteristics of extreme right-wing parties themselves. By making use of large-scale survey data (N = 49,801) together with country-level statistics and expert survey data, we are able to explain extreme right-wing voting behaviour from this multilevel perspective. Our results show that cross-national differences in support of extreme right-wing parties are particularly due to differences in public opinion on immigration and democracy, the number of non-Western residents in a country and, above all, to party characteristics of the extreme right-wing parties themselves

    On the effectiveness of noise masks: Naturalistic vs. un-naturalistic image statistics

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    AbstractIt has been argued that the human visual system is optimized for identification of broadband objects embedded in stimuli possessing orientation averaged power spectra fall-offs that obey the 1/fÎČ relationship typically observed in natural scene imagery (i.e., ÎČ=2.0 on logarithmic axes). Here, we were interested in whether individual spatial channels leading to recognition are functionally optimized for narrowband targets when masked by noise possessing naturalistic image statistics (ÎČ=2.0). The current study therefore explores the impact of variable ÎČ noise masks on the identification of narrowband target stimuli ranging in spatial complexity, while simultaneously controlling for physical or perceived differences between the masks. The results show that ÎČ=2.0 noise masks produce the largest identification thresholds regardless of target complexity, and thus do not seem to yield functionally optimized channel processing. The differential masking effects are discussed in the context of contrast gain control

    Evaluating forecasts of extreme events for hydrological applications: an approach for screening unfamiliar performance measures

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    Many different performance measures have been developed to evaluate field predictions in meteorology. However, a researcher or practitioner encountering a new or unfamiliar measure may have difficulty in interpreting its results, which may lead to them avoiding new measures and relying on those that are familiar. In the context of evaluating forecasts of extreme events for hydrological applications, this article aims to promote the use of a range of performance measures. Some of the types of performance measures that are introduced in order to demonstrate a six-step approach to tackle a new measure. Using the example of the European Centre for Medium-Range Weather Forecasts (ECMWF) ensemble precipitation predictions for the Danube floods of July and August 2002, to show how to use new performance measures with this approach and the way to choose between different performance measures based on their suitability for the task at hand is shown. Copyright © 2008 Royal Meteorological Societ

    Representations of poverty in British newspapers: a case of ‘othering’ the threat?

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    The meanings of social problems like poverty develop within the public sphere. This paper uses the theory of social representations to examine how poverty is represented in British newspapers. Poverty has been discussed and interpreted in numerous ways, and newspapers not only provide a platform for these elaborations but also contribute to shaping public understanding on the issue. The study sampled news coverage on poverty in four British newspapers during two randomly chosen one-month periods in the years 2001 and 2011. The data set of news reports (n = 274) was thematically analysed to examine representations of poverty. The study found that in the domestic context, media represents poverty as a problem limited to vulnerable groups such as children and the elderly. With a lack of discussion on the wider socio-economic causes and contributing factors, poverty within the UK appears as an ‘orphan phenomenon’ with an unknown genesis. In contrast, the representations of poverty outside the UK are vivid and elaborate, and the news reports hold the socio-political inefficiency of countries responsible for poverty. The study also found that the media uses poverty to make sense of catastrophic events in society: the September 11, 2001 terrorist attacks in the United States and the London riots of 2011 were both anchored using poverty. This paper discusses the representational dynamics of these findings and argues that the media representations distance general society from poverty, representing it as a problem of the othe

    Cycles in politics : wavelet analysis of political time-series

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    Spectral analysis and ARMA models have been the most common weapons of choice for the detection of cycles in political time-series. Controversies about cycles, however, tend to revolve about an issue that both techniques are badly equipped to address: the possibility of irregular cycles without fixed periodicity throughout the entire time-series. This has led to two main consequences. On the one hand, proponents of cyclical theories have often dismissed established statistical techniques. On the other hand, proponents of established techniques have dismissed the possibility of cycles without fixed periodicity. Wavelets allow the detection of transient and coexisting cycles and structural breaks in periodicity. In this paper, we present the tools of wavelet analysis and apply them to the study to two lingering puzzles in the political science literature: the existence to cycles in election returns in the United States and in the severity of major power wars.Fundação para a CiĂȘncia e a Tecnologia (FCT

    Inferring the dynamics of rising radical right-wing party support using Gaussian processes

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    The use of classical regression techniques in social science can prevent the discovery of complex, nonlinear mechanisms, and often relies too heavily on both the expertise and prior expectations of the data analyst. In this paper, we present a regression methodology that combines the interpretability of traditional, well used, statistical methods with the full predictability and flexibility of Bayesian statistics techniques. Our modelling approach allow us to find and explain the mechanisms behind the rise of Radical Right-wing Populist parties (RRPs), that we would have been unable to find using traditional methods. Using Swedish municipality level data (2002-2018) we find no evidence that the proportion of foreignborn residents is predictive of increases in RRP support. Instead, education levels and population density are the significant variables that impact the change in support for the RRP, in addition to spatial and temporal control variables. We argue that our methodology, which produces models with considerably better fit of the complexity and nonlinearities often found in social systems, provides a better tool for hypothesis testing and exploration of theories about RRPs and other social movements
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