Wyniki wyszukiwania - BazTech

1

Analysis of Rheological Properties of Cement Composites Based on Waste Materials

Zakrzewski Mateusz, Domski Jacek

Rocznik Ochrona Środowiska

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2023

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Tom 25

159--173

EN

This report presents the results and analysis of long-term properties of fiber-reinforced cement composite based on waste aggregate. The long-term tests were carried out on the stand proposed by the authors for simultaneously testing three beams with dimensions of 100x200x2900 mm. A total of 8 mixtures of cement composites with aggregate from ceramic waste and waste sand were tested. Three beams were made for each mixture. One without dispersed reinforcement and two with 0.5% and 1.0% fiber reinforcement ratios. As dispersed reinforcement, steel cord and hooked steel fibers were used. The beams were subjected to a four-point bending test. The research was carried out for 1000 days. An optical system was used as an innovative solution in long-term research. Based on the measurements, the creep coefficient in the mid-span of the beams was determined, and the crackings of the beams were analysed. The results obtained using manual measuring devices and the optical system were compared. A good convergence of measurement methods was observed. During the analysis of the results, the coefficients modifying the method for calculating the crack width included in Eurocode 2 were determined.

2

Niestandardowe badania presjometryczne

Tarnawski M.

Inżynieria i Budownictwo

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2017

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R. 73, nr 5

266--268

PL

Sposoby wykonywania badań presjometrem Ménarda i interpretacji ich wyników są znormalizowane. Można je jednak także realizować w sposób niestandardowy. Poddano tu analizie wyniki badań cyklicznych i długotrwałych przeprowadzonych ostatnio w Polsce na potrzeby praktyki inżynierskiej. Oceniono, że badania w cyklach odciążenie – obciążenie mogą posłużyć dokładniejszemu określeniu wartości modułów presjometrycznych, a dzięki badaniom długotrwałym można lepiej opisać zjawiska pełzania gruntu.

EN

Methods for Ménard pressuremeter testing and interpreting the results are normalized. However, they can also be carried out in a nonstandard way. The results of cyclic and long-term tests conducted recently in Poland for the needs of engineering practice have been analyzed here. It was noted that cyclic tests can be used for more accurate defining of pressuremeter modulus values, and the phenomenon of soil creep can be better understood through long-term tests.

3

Wyniki wstępnych badań nad długookresowym rozwojem krajowego systemu wytwarzania energii elektrycznej w Polsce

Pluta M., Wyrwa A., Mirowski T., Zyśk J.

Polityka Energetyczna

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2012

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T. 15, z. 4

85-96

PL

W artykule przedstawiono wyniki wstępnych badań nad długookresowym rozwojem Krajowego Systemu Elektroenergetycznego (KSE) w Polsce. W szczególności zbadano wpływ cen uprawnień do emisji CO2 (EUA) wynikających z dwóch scenariuszy Energetycznej Mapy Drogowej 2050 na zmiany w strukturze mocy wytwórczych oraz produkcji w KSE. Głównym narzędziem analitycznym wykorzystanym w pracy był generator modeli systemów energetycznych - TIMES. W artykule zaprezentowano zbudowany i wykorzystany do analizy referencyjny model krajowego systemu wytwarzania energii elektrycznej w Polsce. Przedstawiono podstawowe założenia obliczeniowe obejmujące prognozy: cen i poda nośników energii pierwotnej, cen uprawnień do emisji CO2 zapotrzebowania na energię elektryczną oraz parametrów techniczno-ekonomicznych stosowanych technologii energetycznych. Otrzymane wyniki wskazują na istotne zmiany w strukturze paliwowej i technologicznej KSE do roku 2050 spowodowane polityką dekarbonizacyjną. Zmiany te pogłębia wzrost ceny EUA. Znacząco wzrośnie rola źródeł niskoemisyjnych: odnawialnych, głównie elektrowni wiatrowych i elektrociepłowni opalanych biomasą, elektrowni jądrowych, elektrowni opalanych węglem brunatnym wyposażonych w technologie CCS.

EN

This paper presents the results of preliminary studies on the long-term development of the power system in Poland. In particular, it analyzes the impact of the price of CO2 emission allowances resulting from the two scenarios of the Energy Roadmap 2050 on the change in the structure of generating capacity and production. The main analytical tool used in the examination was the TIMES model generator. The paper further describes the Reference Energy System developed and used. The main computational assumptions include predictions of the following: prices and supply of primary energy sources, prices of CO2 emission allowances (EUA), the demand for electricity, the technical and economic parameters of energy technologies. The results revealed significant changes in the structure of fuels and technologies up to 2050 caused by the decarbonization policy. These changes deepen with the increase in the EUA price. The role of low carbon technologies such as: renewables, mainly wind turbines and biomass CHPs, nuclear power plants, brown coal power plants equipped with CCS will significantly increase.

4

Long-term population trends of corvids wintering in urban parks in central Poland

Mazgajski T., Żmihorski M., Halba R., Woźniak A.

Polish Journal of Ecology

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2008

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Vol. 56, nr 3

521-526

EN

Changes in the numbers of corvids wintering in Warsaw (Central Poland), in the last sixteen years were analyzed. Four species were studied: Rook Corvus frugilegus L., Jackdaw C. monedula L., Hooded Crow C. corone cornix L. and Magpie Pica pica (L.) The results were based on density data for birds foraging in three urban parks. The bird counts were conducted in November and December 1988.2003. It was found that the number of wintering Rooks decreased significantly (0.5 fold), populations of Jackdaws and Hooded Crows - increased (4.25 and 3.95 fold, respectively), and no apparent trends were observed for Magpies during this period. Observed trends for Rooks as well as comparisons of limited data gathered earlier in other areas may confirm suggestions about the changing of migration routes of this species.

5

Seasonal and long-term export rates of nutrrients with surface runoff in the river Jorka catchment basin (Masurian Lakeland, Poland)

Rybak J.

Polish Journal of Ecology

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2002

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Vol. 50, nr 4

439-458

EN

In the Masurian Lakeland a medium size catchment basin of the Jorka river-lake system (about 65 km ^2) was studied intensively in 1996-1998 (April-October) and compared with the data from the late 1970s. Nutrients (TP, TKN, N-NO3) and chlorides were monitored in 15 short lakeshore streams draining small subcatchments that differed in land use. The annual and monthly concentration values of nutrients were measured as well as the annual load in kg ha^-1 year^-1. The data indicate that in a mosaic, hilly region the export rates from the diversified small catchments of both TP and TN tend to be low, lower than in other, non-mosaic areas; the values of export rates are mainly dependent on the discharge in the subcatchments; that is why the values for 1998 and/or 1997 were usually lower than for other years. There is a tendency to lower concentration for nutrients (including chlorides) and export rates in the subcatchments objected to low impact of agriculture (forest, wetland) than in the subcatchments dominated by cropland. Extremely high values were found for a few catchments with cropland, additionally polluted by sewage disposal in the vicinity.