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Number of results: 52
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Abstract

Power spectrum techniques were applied to two time series of wind speed values recorded at the Arctowski Station in order to investigate the influence of turbulent and laminar air flow on the quasi-periodicity of the micro-scale wind structure.

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Authors and Affiliations

Ewa Skrzypczak
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Abstract

The aim of the article is a preliminary assessment of the possibility of using ATES (Aquifer Thermal Energy Storage) technology for the seasonal storage of heat and cold in shallow aquifers in Poland. The ATES technology is designed to provide low-temperature heat and cold to big-area consumers. A study by researchers from the Delft University of Technology in the Netherlands indicates very favorable hydrogeological and climate conditions in most of Poland for its successful development. To confirm this, the authors used public hydrogeological data, including information obtained from 1324 boreholes of the groundwater observation and research network and 172 information sheets of groundwater bodies (GWBs). Using requirements for ATES systems, well-described in the world literature, the selection of boreholes was carried out in the GIS environment, which allowed aquifers that meet the required criteria to be captured. The preliminary assessment indicates the possibility of the successful implementation of ATES technology in Poland, in particular in the northern and western parts of the country, including the cities of: Gdańsk, Warsaw, Wrocław, Bydgoszcz, Słupsk, and Stargard.

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Authors and Affiliations

Maciej Miecznik
Robert Skrzypczak
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Abstract

Obervations of wind directions and air temperatures in Hornsund, Spitsbergen, in 1978—1985 were used to compute frequency distribution of wind directions and mean air temperatures at particular wind directions. Prevailing easterly winds (60°, 90° and 120°) resulted in lower air temperatures (to —2.2°C) than winter and spring means and in higher (nearly 1°C) than summer and autumn mean temperatures. Greatest positive deviations from mean seasonal temperatures are observed in winter at southerly and southwesterly winds and reach 10°C. Greatest negative deviations from mean seasonal temperatures are noted at northerly winds (330° and 360°) in autumn and reach —3.7°C.

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Authors and Affiliations

Danuta Wielbińska
Ewa Skrzypczak
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Abstract

Observations from 1978—81, 1983 and 1985 collected at the Polish Polar Arctowski Station (King George Island, South Shetland Islands) were used to calculate frequencies of wind directions in 30° sectors and mean air temperatures observed at each wind direction. Results reveal that all over the year the warmest air masses flow onto the South Shetland Islands from the northwest while the coolest ones from the southeast and east.

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Authors and Affiliations

Danuta Wielbińska
Ewa Skrzypczak
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Abstract

The paper presents an approach of numerical modelling of alloy solidification in permanent mold and transient heat transport between the casting and the mold in two-dimensional space. The gap of time-dependent width called "air gap", filled with heat conducting gaseous medium is included in the model. The coefficient of thermal conductivity of the gas filling the space between the casting and the mold is small enough to introduce significant thermal resistance into the heat transport process. The mathematical model of heat transport is based on the partial differential equation of heat conduction written independently for the solidifying region and the mold. Appropriate solidification model based on the latent heat of solidification is also included in the mathematical description. These equations are supplemented by appropriate initial and boundary conditions. The formation process of air gap depends on the thermal deformations of the mold and the casting. The numerical model is based on the finite element method (FEM) with independent spatial discretization of interacting regions. It results in multi-mesh problem because the considered regions are disconnected.

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Authors and Affiliations

T. Skrzypczak
L. Sowa
E. Węgrzyn-Skrzypczak
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Abstract

Presented paper shows the mathematical and numerical approaches for modelling of binary alloy solidification solved by the Finite Element Method (FEM). The phenomenon of shrinkage cavities formation process is included in the numerical model. Multiple macroscopic cavities can be modelled within the single casting volume. Solid, liquid and gaseous phases with different material properties are taken into account during solidification process. Mathematical model uses the differential equation of heat diffusion. Modification of specific heat is used to describe the heat releasing during liquid-solid phase change. Numerical procedure of shrinkage cavities evolution is based on the recognition of non-connected liquid volumes and local shrinkage computation in the each of them. The recognition is done by the selection of sets of interconnected nodes containing liquid phase in the finite element mesh. Original computer program was developed to perform calculation process. Obtained results of temperature and shrinkage cavities distributions are presented and discussed in details.

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Authors and Affiliations

T. Skrzypczak
L. Sowa
E. Węgrzyn-Skrzypczak
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Abstract

Statistical conformity criteria for the compressive strength of concrete are a matter of debate. The criteria can have prejudicial effects on construction quality and reliability. Hence, the usefulness of statistical criteria for the small sample size n = 3 is questioned. These defects can cause a reduction in the quality of produced concrete and, consequently, too much risk for the recipient (investor). For this reason, the influence of conformity control on the value of the reliability index of concrete and reinforced concrete has been determined. The authors limited their consideration to the recommended standards PN-EN 206-1, PN-EN 1992 and ISO 2394 method of reliability index, which belongs to the analytical methods FORM (First Order Reliability Method). It assumes that the random variables are defined by two parameters of the normal distribution or an equivalent normal: the mean and the standard deviation. The impact of conformity control for n = 3 for concrete structures, designed according to the Eurocode 1992, for which the compressive strength of concrete is the capacity dominant parameter (sensitivity factor of dominating resistance parameter according to the FORM is 0.8), has been determined by evaluation of the reliability index.

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Authors and Affiliations

I. Skrzypczak
L. Buda-Ożóg
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Abstract

The aim of the study was to compare anaesthesia protocol utilizing combination ketamine/ medetomidine with epidural lidocaine or morphine to orthopaedic surgery in rabbits. All rabbits received intramuscularly medetomidine (0.5 mg/kg) and ketamine (20 mg/kg). In group L (n=13) epidural injection was performed with lidocaine (3 mg/kg) and in group M (n=13) with morphine (0.1 mg/kg) diluted with sterile saline to 0.6 ml. Rabbits underwent bilateral mosaicplasty surgery. Heart rate (HR), systolic (SBP), diastolic (DBP) and mean arterial blood pressure (MAP), arte- rial oxygen saturation (SpO2) and respiratory rate (RR) were measured every 5 minute during surgical procedure. Duration of sensory blockade was measured based on toe pinch reflex and recorded.

Hemodynamic parameters were comparable at baseline in both groups. We did not observe significant differences in HR, RR, SBP, DBP, MAP between group L and M. Intragroup statistical analysis revealed differences at different time points in group M in terms of HR, SBP, DBP, MAP. In rabbits in group M blood pressure dropped while HR increased over time. In both groups a decrease in SpO2 was observed. Mean duration of loss of the toe pinch reflex was similar between group L and M, and amounted to 72.79±34.48 and 82.80±17.85 minutes, respectively.

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Authors and Affiliations

A. Antończyk
B. Liszka
P. Skrzypczak
Z. Kiełbowicz
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Abstract

The evaluation of effect of the grass and broadleaf weed control of different mixture rates of mesotrione plus pethoxamid and terbuthylazine applied postemergence in maize was conducted in the field experiments during the 2005 and 2006 growing seasons. There was no phytotoxicity observed on maize after herbicide treatments. Herbicide mixture provided higher levels of Echinochloa crus-galii (L.) Beauv. control than mesotrione used alone. In the postemergence trials, the broadleaf weeds, except Chenopodium album L., were not well controlled by the mesotrione-alone treatment. The addition of pethoxamid plus terbuthylazine to mesotrione significantly improved the control of broadleaf weeds. Mesotrione and mesotrione plus pethoxamid and terbuthylazine treated plots were always among the highest yielding as compared to untreated plots. Any reductions in cob and grain yield were always associated with high weed fresh matter yields indicating that it was the weed competition that led to reduced yield and not herbicide phytotoxicity.

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Authors and Affiliations

Grzegorz. A. Skrzypczak
Jerzy A. Pudełko
Wojciech Waniorek
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Abstract

Poland is characterized by a number of factors which adversely affect the agricultural economy, so this paper will aim to present the possibilities of using multi-criteria decision-making methods of Analytical Hierarchy Process (AHP) in the analysis of the spatial structure of rural areas. AHP is a widely used tool for making complex decisions based on a large number of criteria, such as, for example, land consolidation works on fragmented agricultural land. The first step is to formulate the decision-making process, then the assessment criteria and the solution variants guided by expert knowledge are determined.

A ranking, according to which the order of land consolidation and land exchange works in the studied area should be determined, will be defined by using decision-making models of the AHP method. The basis for calculations will be the weights received for the factors/parameters defined for the five thematic groups. Calculations for individual villages will bemade, and then the obtained results will allow creating a ranking for the studied commune, allowing for the effective (in terms of economic and socio-economic) spending of funds for this purpose. The presented method can be successfully used to conduct analogous analyses for any area.

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Authors and Affiliations

Grzegorz Oleniacz
Izabela Skrzypczak
Przemysław Leń
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Abstract

In this paper, the mathematical model and numerical simulations of the molten steel flow by the submerged entry nozzle and the filling process of the continuous casting mould cavity are presented. In the mathematical model, the temperature fields were obtained by solving the energy equation, while the velocity fields were calculated by solving the momentum equations and the continuity equation. These equations contain the turbulent viscosity which is found by solving two additional transport equations for the turbulent kinetic energy and its rate of dissipation. In the numerical simulations, coupling of the thermal and fluid flow phenomena by changes in the thermophysical parameters of alloy depending on the temperature has been taken into consideration. This problem (2D) was solved by using the finite element method. Numerical simulations of filling the continuous casting mould cavity were performed for two variants of liquid metal pouring. The effect of the cases of pouring the continuous casting mould on the velocity fields and the solid phase growth kinetics in the process of filling the continuous casting mould was evaluated as these magnitudes have an influence on the high quality of the continuous cast steel slab.

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Authors and Affiliations

L. Sowa
T. Skrzypczak
P. Kwiatoń
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Abstract

Direct applications in agriculture are among the most prospective development lines of geothermal water and energy. In many countries such uses have already been ongoing. Poland also has suitable natural conditions and geothermal waters’ potential for agricultural development as well as for applications related to agriculture. Moreover, such applications in agriculture – if taking place after earlier use of geothermal waters e.g. for energetic or other purposes – would be the realization of the idea of the closed cycle economy. The first research and development works on geothermal waters and energy applications in agriculture in Poland were carried out in the early 1990s. In recent years this subject has once again sparked a growing interest. The paper presents geothermal water resources potential as well as circumstances, rationale, selected relevant estimations and proposed zones in the country for their uses (as raw material and heat source) in the agricultural sector of the country. The use of geothermal waters in agriculture would be an important element in the chain of agricultural production and agri-food processing, contributing to the increase in the use of locally available natural resources, as well as reducing emissions when using these resources for energetic purposes. The topic is presented against the background of a brief review of the state of geothermal water applications in agriculture in the world and in Europe, which convinces the legitimacy and need for the development of such use of geothermal water as a raw material for agriculture also in Poland.

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Authors and Affiliations

Robert Skrzypczak
Beata Kępińska
ORCID: ORCID

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