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1

Analysis of Temperatures in the Cold Storage of Finished Products

Bogdanovská Gabriela, Stehlíková Beáta, Kačur Ján

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 3

54--66

EN

The analysis of temperatures in the cold store of finished products was performed due to the occurrence of temperature fluctuations. The analysis in the report was conducted using Kruskal-Wallis test, Bartlett test, Nemenyi’s test Statistical analysis of measured values in individual months. The relationship between the temperature in the cold store and the outside air temperature was investigated. Quality tools were also used in the thesis. The causes of temperature fluctuations were determined by Cause-Effect diagnostics. The relationship between the main causes was analyzed with Relation Diagram. Corrective measures were then determined to minimize the temperature fluctuations in the cold store.

2

Fourier variant homogenization of the heat transfer processes in periodic composites

Wierzbicki E., Kula D., Wodzyński Ł.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 3

719--726

EN

The well-known parabolic Heat Transfer Equation is a simplest recognized description of phenomena related to the heat conductivity in solids with microstructure. However, it is a tool difficult to use due to the discontinuity of coefficients appearing here. The purpose of the paper is to reformulate this equation to the form that allows to represent solutions in the form of Fourier’s expansions. This equivalent re-formulation has the form of infinite number of equations with Fourier coefficients in expansion of the temperaturę field as the basic unknowns. The first term in Fourier representation, being an average temperature field, should satisfy the well-known parabolic heat conduction equation with Fourier coefficients as fields controlling average temperature behavior. The proposed description takes into account changes of the composite periodicity accompanying changes in the variable perpendicular to the surfaces separating components, concerning FGM-type materials and can be treated as the asymptotic version of Heat Transfer Equation obtained as a result of a certain limit passage where the cell size remains unchanged.

3

Wykorzystanie naturalnych fluktuacji parametrów przepływu do pomiaru wektora prędkości

Ligęza P., Jamróz P., Poleszczyk E., Socha K.

Prace Instytutu Mechaniki Górotworu PAN

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2012

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Vol. 14, no. 1-4

203--211

PL

Wadą standardowych metod anemometrii cieplnej jest trudność zastosowania i znacząca niepewność pomiaru w przepływach, w których występują fluktuacje temperatury i innych wielkości fizycznych o znacznej amplitudzie. Wynika to z oddziaływania fluktuacji na sygnał pomiarowy. W pracy zaproponowano nową metodę wyznaczania dwuwymiarowego lub trójwymiarowego wektora prędkości przepływu cieczy i gazów, która polega na zastosowaniu kilku detektorów fluktuacji temperatury lub innej wielkości fizycznej propagującej z prędkością ośrodka lub większą o znaną wartość. Zaletą proponowanej metody jest niewrażliwość na zmianę parametrów ośrodka oraz brak konieczności wzorcowania czujnika pomiarowego (bezwzględny pomiar wektora prędkości). W pracy przedstawiono opracowany nowatorski czujnik, algorytm przetwarzania sygnału, wyniki badań oraz wskazano potencjalny obszar aplikacyjny.

EN

The main drawback of most thermal anemometry methods is their limited applicability and a major uncertainty in measurements taken in flows where temperature and other physical parameters are subject to large-amplitude fluctuations. The uncertainty is the consequence of fluctuations interfering with the measurement signal. The authors propose a new method of finding a 2D or 3 D vector of flow velocity of fluids, involving the use of several detectors of temperature fluctuations or other physical quantity propagating with the speed equal to that of the medium flow or larger by a known amount. The advantage of the proposed method is that it is insensitive to variations of medium parameter and the sensor need not be calibrated (absolute measurement of the velocity vector). The paper briefly describes the novel solution, the signal processing algorithm and the range of potential applications.

4

Soil fauna community dynamics during soil thawing period in the subalpine and alpine forests of Western China

Wu F., Yang W., Yang Y., Wang A., Tan B.

Polish Journal of Ecology

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2012

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Vol. 60, nr 4

755--766

EN

The frequently changed temperature could have great effects on soil fauna community during soil thawing period in cold areas. Therefore, soil faunas were investigated in both the soil organic layer (OL) and mineral soil layer (ML) in the primary fir (Abies faxoniana) forest (PF), fir and birch (Betula albosinensis) mixed forest (MF) and secondary fir forest (SF) in the eastern Qinghai–Tibet Plateau every ten days between March 5 and April 25, 2009. Soil macrofauna was picked up by hand in the fields. Mesofauna was collected and separated from the soil samples by Baermann and Tullgren methods, respectively. The dominated species of macrofauna belonged to Coleoptera and Diptera at the early stage of soil thawing, and to Coleoptera, Diptera, Araneae and Hymenoptera at the later stage. However, the dominated species of mesofauna belonged to Nematode, Collembola, and Acari in the whole soil thawing. The density, number of taxa, and diversity index of soil fauna showed significant change with temperature fluctuations and reached an obvious peak when soil temperatures rising above 0[degrees]C. The density and number of taxa of macrofauna in both the OL and ML were the lowest on March 5 in the three forests, but the density of mesofauna in both the OL and ML was the highest on March 25, except for the ML in the PF. These results implied that soil fauna community was sensitive to temperature fluctuations, which is important in understanding the ecological processes in the winter–spring transitional period.

5

Mean and turbulent thermal fields due to film cooling via an eddy heat diffusivity closure

Karcz M.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2006

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Vol. 10, No 4

377-390

EN

The two-equation level of turbulent heat flux modelling is considered for application in film cooling instead of the turbulent Prandtl number concept. The investigations involve numerical analysis of mean and fluctuating temperature fields near the coolant injection inlet. The results of the implemented coupled v2- f-k0-E0 model are compared with measurement data for a flat plate cooled with compound angle orientation of discrete in-jection holes. The results of numerical analysis agree very well with the experimental data. The coupled model offers a detailed picture of gas turbine cooling problems without using time-consuming, inherently unsteady models.