Wyniki wyszukiwania - Biblioteka Nauki

1

Joints of steel sandwich structures

100%

Kozak J.

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tom nr 2

128--134

EN

Steel sandwich structures are perceived as alternatives to single-skin welded structures in the shipbuilding industry due its advantages like significant reduction of mass in relation to typical single skin structure. However, beside problems with their strength properties itself, applications in real structures requires of solving the problem of joining, both for connection sandwich to sandwich as well as sandwiches to single-shell structures. Proper design of joints is connected with some factors like lack of attempt to interior of panel, introduction of additional parts and welds with completely different stiffness. In the paper the results of laboratory fatigue tests of selected joints as well as numerical calculation of stressed for different kind of joints of sandwich structures are presented. As result of calculations optimisation of geometry for selected joints is performed.

2

The variability of the atmospheric precipitation in the region of Wielka Laka dam reservoir

63%

Kozak J. , Jachniak E.

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tom Vol. 27, nr 1-2

1--17

EN

The aim of this research was the analysis of the precipitation variability in the last decade in the region of Wielka Laka reservoir. The daily sums of the precipitation (from 2005 to 2018) were the research material. They were obtained from the Aqua S.A. in Bielsko-Biala. The measurements were carried out according to the standard method using the Hellman pluviometer. In research the precipitation indicators were used, which are commonly applied. They were used to description of the precipitation characteristics. The frequency of days with precipitation at the certain height was determined according to the Olechnowicz-Bobrowska classification. The classification of individual years and months in respect of the excess or lack precipitation was conducted based on the Kaczorowska method. In the analysed multi-year period (2005–2018) the dry years prevailed, however the significant regularity wasn’t noticed. In the analysed multi-year period the highest rainfall was recorded in 2010 year, when in May the total precipitation was summarised at the 171 mm level. The recorded precipitation accompanied the inflow of air masses in the directions from the east (E) to the northwest (NW).

3

Występowanie miejskiej wyspy ciepła w Bielsku-Białej na podstawie przestrzennych rozkładów temperatur powietrza

51%

Kozak J. , Zając B. , Graczyk T.

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tom Vol. 21, nr 4

43--48

PL

W artykule przedstawiono problematykę występowania miejskiej wyspy ciepła. Zjawisko to zaobserwowano dla obszaru Bielska-Białej na podstawie danych rozkładu przestrzennego temperatur powietrza uzyskanych w 2015 roku. Do realizacji zaplanowanych badań wykonano mapy rozkładu przestrzennego temperatur powietrza – uśrednionych dla roku, jak również dla okresu letniego i zimowego. Dodatkowo, dla wybranych dzielnic Bielska-Białej rozpoznano występowanie termicznych typów pogody, a także określono czas trwania termicznych pór roku. W wyniku przeprowadzonych prac stwierdzono zróżnicowanie temperatur powietrza (dochodzące do 3,4°C) na badanym obszarze w skali roku. Potwierdzono ponadto zróżnicowanie czasu trwania termicznych typów pogody i termicznych pór roku. Uzyskane dane umożliwiły określenie obszaru występowania miejskiej wyspy ciepła.

EN

The article presents the problem of the occurrence of an urban heat island. This phenomenon was observed for the Bielsko-Biała area on the basis of data on spatial distribution of air temperatures obtained in 2015. To carry out the planned research, maps of spatial distribution of air temperatures – averaged over the year, as well as for the summer and winter period – were made. Additionally, for selected districts of Bielsko-Biała the occurrence of thermal weather types was recognized and the duration of thermal seasons was determined. As a result of the works carried out, air temperature differences (reaching 3.4°C) were found in the studied area on an annual scale. Moreover, the differentiation in duration of thermal weather types and thermal seasons was confirmed. The data obtained made itpossible to determine the area of the urban heat island.

4

Zmienność stężeń pyłu zawieszonego PM10 w powietrzu na terenie Krościenka nad Dunajcem w latach 2018-2022

51%

Wierzbińska M. , Kozak J. , Zając E.

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tom Vol. 5 (25)

14--22

EN

Frequent exceedances of permissible PM10 concentrations occur mainly during the so-called heating season and are readily noticed not only by environmental protection specialists but also by residents; they are also wildly discussed in the mass media. If the state of elevated concentrations persists for at least several hours, it is generally referred to as smog. The du-ration of smog can range from several hours to several days, causing an increase in morbidity and in the number of deaths. The paper presents the air-sanitary situation in Krościenko nad Dunajcem using the air quality indicator as the concentration of particulate matter PM10. Krościenko is a Carpathian town located in the valley of the Dunajec river. Such a topo-climatic location is conducive to the occurrence of frequent temperature inversions, stagnant cold air and poor ventilation, which results in the concentration of local emissions mainly from domestic boilers. The research period covered the years 2018-2022 of continuous daily D24 PM10 measure-ments. Preliminary comparisons of annual concentrations with selected cities located in moun-tainous and foothill areas of southern Poland indicated the aerosanitary problem of Krościenko. In all analyzed years, the daily norms were exceeded from 46 days in 2022 to 91 days in 2018. This situation occurs as a result of the low-stack emission during the heating period and the poor topoclimatic conditions in Krościenko. However, there is a visible downward trend in con-centrations over the analyzed period, which may have resulted from the gradual reduction of the use of fossil fuels.

5

A study on the effects of cold deformation on CMnSi steel structures utilised in the shipbuilding industry

45%

Nguyen V. N. , Nguyen D. N. , Kozak J. , Nguyen X. P. , Nguyen D. T.

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tom nr 3

135--141

EN

This article analyses the effects of deformation on the structure of CMnSi steel at various deformation levels. After hot forging, the structure of CMnSi steel comprises coarse-sized alpha and pearlite particles. The average grain size of steel after forging was 100 μm. After hot rolling, the grain size gradually decreases, with the average size of the ferrite and pearlite grains measured as 60 μm. After that, CMnSi steel was subjected to cold deformation at levels of 40%, 60%, and 80%. The grain size of the CMnSi steel sample after 80% cold deformation reached level 7, corresponding to about 25 μm. For a deformation level of 40%, the grain size was level 5, corresponding to 40 μm, while a deformation level of 60% produced a grain size of 35 μm, corresponding to level 6. In addition, scanning electron microscopy showed that after 80% deformation, smaller particles with a size of about 5 μm appear inside the parent particles. Moreover, energy-dispersive X-ray spectroscopy analysis revealed the carbide appearance in the form M23C6, with M being a mixture of Fe and Mn. These carbides have a fine size of about 1–2 μm and contribute to the prevention of particle growth during subsequent heat treatments.

6

Using Artificial Neural Networks for predicting ship fuel consumption

32%

Nguyen V. G. , Sakthivel R. , Rudzik K. , Kozak J. , Sharma P. , Pham N. D. K. , Nguyen P. Q. P. , Nguyen X. P.

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tom nr 2

39--60

EN

In marine vessel operations, fuel costs are major operating costs which affect the overall profitability of the maritime transport industry. The effective enhancement of using ship fuel will increase ship operation efficiency. Since ship fuel consumption depends on different factors, such as weather, cruising condition, cargo load, and engine condition, it is difficult to assess the fuel consumption pattern for various types of ships. Most traditional statistical methods do not consider these factors when predicting marine vessel fuel consumption. With technological development, different statistical models have been developed for estimating fuel consumption patterns based on ship data. Artificial Neural Networks (ANN) are some of the most effective artificial methods for modelling and validating marine vessel fuel consumption. The application of ANN in maritime transport improves the accuracy of the regression models developed for analysing interactive relationships between various factors. The present review sheds light on consolidating the works carried out in predicting ship fuel consumption using ANN, with an emphasis on topics such as ANN structure, application and prediction algorithms. Future research directions are also proposed and the present review can be a benchmark for mathematical modelling of ship fuel consumption using ANN.