Thermal Comfort Aspects of Solar Gains during the Heating Season

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Operation Testing of an Advanced Personalized Ventilation System

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Persistence analysis of velocity and temperature fluctuations in convective surface layer turbulence

Persistence is defined as the probability that the local value of a fluctuating field remains at a particular state for a certain amount of time, before being switched to another state. The concept of persistence has been found to have many diverse practical applications, ranging from non-equilibrium statistical mechanics to financial dynamics to distribution of time scales in turbulent flows and many more. In this study, we carry out a detailed analysis of the statistical characteristics of the persistence probability density functions (PDFs) of velocity and temperature fluctuations in the surface layer of a convective boundary layer, using a field-experimental dataset. Our results demonstrate that for the time scales smaller than the integral scales, the persistence PDFs of turbulent velocity and temperature fluctuations display a clear power-law behaviour, associated with self-similar eddy cascading mechanism. Moreover, we also show that the effects of non-Gaussian temperature fluctuations act only at those scales which are larger than the integral scales, where the persistence PDFs deviate from the power-law and drop exponentially. Furthermore, the mean time scales of the negative temperature fluctuation events persisting longer than the integral scales are found to be approximately equal to twice the integral scale in highly convective conditions. However, with stability this mean time scale gradually decreases to almost being equal to the integral scale in the near neutral conditions. Contrarily, for the long positive temperature fluctuation events, the mean time scales remain roughly equal to the integral scales, irrespective of stability

Hysteretic behavior of spatially coupled phase-oscillators

Motivated by phenomena related to biological systems such as the synchronously flashing swarms of fireflies, we investigate a network of phase oscillators evolving under the generalized Kuramoto model with inertia. A distance-dependent, spatial coupling between the oscillators is considered. Zeroth and first order kernel functions with finite kernel radii were chosen to investigate the effect of local interactions. The hysteretic dynamics of the synchronization depending on the coupling parameter was analyzed for different kernel radii. Numerical investigations demonstrate that (1) locally locked clusters develop for small coupling strength values, (2) the hysteretic behavior vanishes for small kernel radii, (3) the ratio of the kernel radius and the maximal distance between the oscillators characterizes the behavior of the network

Maps on 3-manifolds given by surgery

Suppose that the 3-manifold M is given by integral surgery along a link L in S^3. In the following we construct a stable map from M to the plane, whose singular set is canonically oriented. We obtain upper bounds for the minimal numbers of crossings and non-simple singularities and of connected components of fibers of stable maps from M to the plane in terms of properties of L.Comment: 22 pages, 13 figures. Accepted for publication by Pacific J. Mat

A labirintus-elv: Férfiasságkonstrukciók és térszerkezetek összefüggései a magyar szerzői filmben

A szöveg a magyar szerzői film férfiasságkonstrukcióinak és egyes térszerkezeteinek összefüggéseit vizsgálja

Importance of Soil Quality in Environment Protection

Soil quality can be characterised by the harmony between it’s physical and biological state and the fertility. From the practical crop production viewpoint, some important contrasting factors of soil quality are: (1) soil looseness – compaction; (2) aggregation – clod and dust formation; friable structure – smeared or cracked structure; (3) organic material: conservation – decrease; (4) soil moisture: conservation – loss; water transmission – water-logging; (5) at least soil condition as a result of the long term ef ect of land use moderates or strengthens climatic harm. In our long-term research project practical soil quality factors were examined in arable i eld and experimental conditions. We state that prevention of the soil quality deterioration can be done by the developing and maintaining harmony between land use and environment. Elements of the soil quality conditions such as looseness, aggregation, workability, organic matter, water transport are examined and the improving methods are suggested. Tillage and production factors which can be adopted to alleviate the harmful climatic impacts are also summarised