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Number of results: 5
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Abstract

This paper describes a forecasting exercise of close-to-open returns on major global stock indices, based on high-frequency price patterns that have become available in foreign markets overnight. Generally speaking, out-of-sample forecast performance depends on the forecast method as well as the information that the forecasts are based on. In this paper both aspects are considered. The fact that the close-to-open gap is a scalar response variable to a functional variable, namely an overnight foreign price pattern, brings the prediction exercise in the realm of functional data analysis. Both parametric and non-parametric functional data analysis are considered, and compared with a simple linear benchmark model. The information set is varied by dividing global markets into three clusters, Asia-Pacific, Europe and North-America, and including or excluding price patterns on a per-cluster basis. The overall best performing forecast is nonparametric using all available information, suggesting the presence of nonlinear relations between the overnight price patterns and the opening gaps.

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Authors and Affiliations

Jan G. De Gooijer
Cees G.H. Diks
Łukasz T. Gątarek
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Abstract

An approach – relaying on application of nanofluid as a working fluid, to improve performance of the two-phase thermosyphon heat exchanger (TPTHEx) has been proposed. The prototype heat exchanger consists of two horizontal cylindrical vessels connected by two risers and a downcomer. Tube bundles placed in the lower and upper cylinders work as an evaporator and a condenser, respectively. Distilled water and nanofluid water-Al2O3solution were used as working fluids. Nanoparticles were tested at the concentration of 0.01% and 0.1% by weight. A modified Peclet equation and Wilson method were used to estimate the overall heat transfer coefficient of the tested TPTHEx. The obtained results indicate better performance of the TPTHEx with nanofluids as working fluid compared to distilled water, independent of nanoparticle concentration tested. However, increase in nanoparticle concentration results in overall heat transfer coefficient decrease of the TPTHEx examined. It has been observed that, independent of nanoparticle concentration tested, decrease in operating pressure results in evaporation heat transfer coefficient increase.

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Authors and Affiliations

Janusz T. Cieśliński
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Abstract

The ethanol fire hazards will become more frequent due to the new established targets for the consumption of renewable energy sources. With this in mind, this paper aims to widen the current knowledge on CFD modelling of such a fire. As previous works rely heavily on the data of small pool fire diameters (below 1 m), this research deals with ethanol pool fire on a one-meter test tray, using our own experimental data. A mathematical model was developed and solved using a commercial CFD package (ANSYS Fluent). A new hybrid RANS-LES (SBES) model was employed to calculate turbulent stresses. Generally, the simulation results showed a good fit with the experimental results for flame temperatures at different elevations. In particular, a minor discrepancy was only observed for the top thermocouple (1.9 m above the tray). The flame heights computed with the CFD model were on average higher than the experimental one. Good agreement was observed for the radiative fraction and the axial temperature profile on the plume centreline. The latter showed an almost perfect fit between the temperature profiles obtained from CFD simulations and those calculated from the plume law for temperature.
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Authors and Affiliations

Robert Cherbański
1
ORCID: ORCID
Leszek Rudniak
1
Piotr Machniewski
1
Eugeniusz Molga
1
ORCID: ORCID
Jarosław Tępiński
2
Wojciech Klapsa
2
Piotr Lesiak
2

  1. Warsaw University of Technology, Faculty of Chemical and Process Engineering, ul. Warynskiego 1, 00-645 Warsaw, Poland
  2. Scientific and Research Centre for Fire Protection of the National Research Institute, ul. Nadwislanska 213, 05-420 Józefów, Poland
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Abstract

The colours of external architecture are crucial to the reception of urbanized space. An appropriate concept is necessary to maintain order and harmony of colours. Decision-making in this respect was analysed, based on Polish and Slovak legal acts. The formal and actual status was compared through analyses of local spatial development plans and site inspections. For a broader perspective, examples from some of the countries are presented. Using a survey, public knowledge of the current legal situation related to colour decision-making was investigated alongside preferences as to who should manage this issue. It was also investigated how space users assessed the external colours of buildings in the areas under study.
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Authors and Affiliations

Elzbieta Czekiel-Świtalska
1
ORCID: ORCID
Alicja Świtalska
1
ORCID: ORCID
Andrea Urlandová
2
ORCID: ORCID

  1. West Pomeranian University of Technology in Szczecin, Faculty of Architecture
  2. Slovak University of Technology, Faculty of Architecture and Design

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