32,055 research outputs found
EXPERIMENTAL TECHNIQUE TO MEASURE THORON GENERATION RATE OF BUILDING MATERIAL SAMPLES USING RAD7 DETECTOR
Thoron (220Rn) is the second most abundant radon isotope in our living environment. In some dwellings it is present in significant amount which calls for its identification and remediation. Indoor thoron originates mainly from building materials. In this work we have developed and tested an experimental technique to measure thoron generation rate in building material samples using RAD7 radon-thoron detector. The mathematical model of the measurement technique provides the thoron concentration response of RAD7 as a function of the sample thickness. For experimental validation of the technique an adobe building material sample was selected for measuring the thoron concentration at nineteen different sample thicknesses. Fitting the parameters of the model to the measurement results, both the generation rate and the diffusion length of thoron was estimated. We have also determined the optimal sample thickness for estimating the thoron generation rate from a single measurement
Modular switched reluctance machines to be used in automotive applications
In the last decades industry, including also that of electrical machines and drives, was pushed near to its limits by the high market demands and fierce competition. As a response to the demanding challenges, improvements were made both in the design and manufacturing of electrical machines and drives. One of the introduced advanced technological solutions was the modular construction. This approach enables on a hand easier and higher productivity manufacturing, and on the other hand fast repairing in exploitation. Switched reluctance machines (SRMs) are very well fitted for modular construction, since the magnetic insulation of the phases is a basic design requirement. The paper is a survey of the main achievements in the field of modular electrical machines, (especially SRMs), setting the focus on the machines designed to be used in automotive applications
The Regional Development of Democratization and Civil Society: Transition, Consolidation, Hybridization, Globalization - Taiwan and Hungary
Different starting points, similar processes and different outcomes can be identified when comparing East Central Europe and East and South Asia. The two regions face similar global challenges, follow regional patterns of democratization and face crises. In communist times, East Central Europe was economically marginalized in the world economy, while some parts of Asia integrated well in the global economy under authoritarian rule. Europeanization and a favorable external environment encouraged the former communist countries to opt for the Western-style rule of law and democracy. Different external factors helped the Third Wave democracies in Asia, especially South Korea and Taiwan, which benefited from the support of the United States and other global economic, military and cultural partnerships to develop their human rights culture and democracy while facing their totalitarian counterparts, namely the People’s Republic of China and North Korea. The very different positions Taiwan and Hungary have in their respective regions follow from the different capacities of their transformation management since 1988-1989. Taiwan preserved its leading role and stable democracy despite the threat to its sovereignty from the People’s Republic of China. Hungary never had such an influential and problematic neighbor and was ensured security and welfare partnership by the European Union, which Taiwan lacked. While Taiwan was less secure, economic and social conditions were more favorable for democratization than those in Hungary. Hungary, in turn, held a leading position in democratization processes in the period of post-communist transition which was lost during the crisis and conflicts of the last decade (after 2006 and especially since 2010). Despite the fact that liberalization prepared the way for peaceful transition in both countries and resulted in similar processes of democratic consolidation in the 1990s, Hungary joined the ‘loser’ group in its region, whereas Taiwan is among the top ‘winning’ countries in its region. Taiwan at the moment is starting comprehensive reform processes toward enhanced democracy, civil rights and the rule of law, and Hungarian development is criticized by many external and internal analysts as straying from the path of European-style consolidated democracies towards illiberal trends and hybridization. Western global concepts of democratization may help to identify similarities and differences, and compare stronger and weaker factors in the democratic transitions in Asia and Europe within the Third Wave democracies
On Bayesian based adaptive confidence sets for linear functionals
We consider the problem of constructing Bayesian based confidence sets for
linear functionals in the inverse Gaussian white noise model. We work with a
scale of Gaussian priors indexed by a regularity hyper-parameter and apply the
data-driven (slightly modified) marginal likelihood empirical Bayes method for
the choice of this hyper-parameter. We show by theory and simulations that the
credible sets constructed by this method have sub-optimal behaviour in general.
However, by assuming "self-similarity" the credible sets have rate-adaptive
size and optimal coverage. As an application of these results we construct
-credible bands for the true functional parameter with adaptive
size and optimal coverage under self-similarity constraint.Comment: 11 pages, 2 figure
Blazhko effect in Cepheids and RR Lyrae stars
The Blazhko effect is the conspicuous amplitude and phase modulation of the
pulsation of RR Lyrae stars that was discovered in the early 20th century. The
field of study of this mysterious modulation has recently been invigorated
thanks to the space photometric missions providing long, uninterrupted,
ultra-precise time series data. In this paper I give a brief overview of the
new observational findings related to the Blazhko effect, like extreme
modulations, irregular modulation cycles and additional periodicities. I argue
that these findings together with dedicated ground-based efforts now provide us
with a fairly complete picture and a good starting point to theoretical
investigations. Indeed, new, unpredicted dynamical phenomena have been
discovered in Blazhko RR Lyrae stars, such as period doubling, high-order
resonances, three-mode pulsation and low-dimensional chaos. These led to the
proposal of a new explanation to this century-old enigma, namely a high-order
resonance between radial modes. Along these lines I present the latest efforts
and advances from the theoretical point of view. Lastly, amplitude variations
in Cepheids are discussed.Comment: 8 pages, 2 figures, invited review, to appear in the conference
proceedings of IAU Symp. 301 Wroclaw, Poland, 2013 August 19-23, Precision
Asteroseismology, Celebration of the Scientific Opus of Wojtek Dziembowsk
Worked shell from the Northern Moluccas
The Northern Moluccas occupy a pivotal geographical zone at the interface of the Island Southeast Asian and Melanesian spheres. Whether one looks at genes, languages, Holocene animal translocations, or the archaeological record, it is clear that the cultures through time on these islands have both been shaped by, and have contributed to shaping, the complex fusion of influences that characterises the Asia/Pacific margin. The project reported on in this monograph intensively investigated this area for the first time, and uncovered a rich range of sites spanning c. 35,000 years of the islands’ history. There are few constants in the archaeological record that can be tracked through time. The vertebrate record of the Northern Moluccas shows dramatic shifts at different points in the past, and the ceramic record is necessarily restricted to the last few thousand years. The pre‑eminence of lithic technology in the study of human cultural change through time is due to its global presence as a robust archaeological constant, but in Island Southeast Asia, and the Northern Moluccas in particular, another constant has emerged: shell technology. From the earliest archaeological deposits at the oldest excavated site, Golo Cave, a range of shell technologies were in use ranging from the formal to the expedient (Szabó et al. 2007; Szabó and Koppel 2015). In contrast, associated lithic technologies were found to be non-standardised and uncomplicated in their manufacture (Szabó et al. 2007). While, to some extent, the early diversification of shell technologies at Golo Cave can be seen as a response to the low-quality lithic materials that were locally available, this in itself does not provide an adequate explanation. The diversity of shell-working from the lowest levels at Golo, both in terms of materials used and reduction techniques employed, clearly implies that a broad tradition of shell-working was well established by the time the site was initially occupied. Additionally, the techniques applied to various types of shell diverge from those applied to lithic material, confirming that shell was no simple technological substitute for stone. The range of stratified sites excavated as part of this archaeological project provides snapshots through time of the rise and decline of a variety of shell-working traditions. Some have clear links beyond the Northern Moluccas whilst others are seemingly idiosyncratic. The shell artefacts will be reported upon site by site, with temporal patterning and extra-Moluccan associations being considered in the discussion section
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