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The effect of maintenance works to physical and chemical conditions of small rivers in agricultural areas

Brysiewicz Adam, Czerniejewski Przemysław, Bonisławska Małgorzata, Dąbrowski Jarosław

Ecological Chemistry and Engineering. S

2022

Vol. 29, nr 1

39--49

Abiotic and biotic bounty of riparian waters may be affected by inadequate maintenance works. Improper planning and execution of maintenance works cause changes to hydrological and hydrochemical condition of water in small rivers, affecting biocenose of riverbeds by modifying the taxonomic composition of organisms inhabiting the regulated river section. Five (5) rivers were subject to studies - Plonia, Mysla, Tywa, Rurzyca, and Wardynka (Odra river basin), which were monitored before and after maintenance works consisting in desilting, mowing and removal of aquatic plants. This study examined hydrological (mean depth and width of small rivers, speed and flow), physical and chemical parameter of water (temperature, pH, O2, N-NO3, N-NH4, P-PO4) before and after dredging of selected rivers. Obtained results and resulting statistical analysis demonstrated increase in hydrological indices - depth, width, speed and flow. Among other physical and chemical properties that significantly increased following completion of maintenance works, were O2 and NH4. NO3 concentration and temperature dropped, but not statistically significant. Changes in hydrological and hydrochemical properties of waters caused by maintenance works may affect biodiversity of the regulated river sections, including changes in composition of ichthyofauna species.

Analysis of the feasibility of replacing fabric skin in half-shell structural designs

Tkaczuk Sławomir, Leszczyński Piotr, Dąbrowski Jarosław

Technologia i Automatyzacja Montażu

2021

nr 4

3--8

Jednym z wielu zagadnień związanych z eksploatacją statków powietrznych są problemy dotyczące zespołów konstrukcyjnych posiadających płócienne pokrycie. Jako jedno z rozwiązań tych problemów, w artykule zaproponowano zastąpienie dotychczasowego pokrycia płóciennego nowym pokryciem w postaci materiału kompozytowego. Obiektem analizy, jakim dysponowali autorzy był statecznik poziomy śmigłowca Mi-2. W artykule przedstawiono rezultaty badań zmęczeniowych cienkościennej struktury tego statecznika poziomego, przeprowadzone dla dwóch przypadków: (I) z usuniętym pokryciem płóciennym oraz (II) z zamontowanym pokryciem kompozytowym. Podczas badań dokonywano pomiaru wartości odkształceń w wybranych punktach struktury statecznika, z wykorzystaniem tensometrów oporowych typu liniowego oraz w układzie rozety prostokątnej. Wyniki badań potwierdziły możliwość zastąpienia pokrycia płóciennego pokryciem kompozytowym.

One of the many issues associated with aircraft operations is that of structural designs with fabric skin. As one of the solutions addressing these problems, this paper proposes replacing the existing fabric skin with a new covering made of a composite material. The object of analysis available to the authors was a horizontal stabilizer of Mi-2 helicopter. This paper presents the results of fatigue tests applied to the thin-walled structure of the horizontal stabilizer, carried out under two scenarios: (I) with the fabric skin removed and (II) with the composite material skin installed. During the tests, strain values were measured at selected points of the stabilizer structure, using linear type resistance strain gauges and in a rectangular rosette arrangement. The test results confirmed the feasibility of replacing the fabric skin with a composite material skin.

Water quality and ichthyofauna habitat conditions in Lake Czolnowskie (N-W Poland)

Brysiewicz Adam, Czerniejewski Przemysław, Kozioł Agnieszka, Rogacki Michał, Dąbrowski Jarosław

Chemistry-Didactics-Ecology-Metrology

2020

R. 25, NR 1-2

113--123

Increasing anthropopressure affects natural ecosystems and may express itself in regional or spot contamination of water and soil environment. The quality of ground and surface waters depends to a large extent on drainage area management, where biogenic substances (i.e. nitrogen, phosphorus and potassium) are transported with surface run-offs to the environment. The article discusses results of studies on the drainage area of Lake Czolnowskie (Zachodniopomorskie Province). Studies covered physical and chemical assessment of soil conditions and water quality; additionally, fish was caught using two independent methods - gillnets and power generator (pursuant to CEN EN 14011 2003 and PN-EN 14011 2006). Results obtained confirm regular run-off of biogenic materials from the surface of farmed drainage area to Lake Czolnowskie. During the period of studies, the reservoir was exposed to i.e. reduction of water oxygen (3.56 mg/dm3) and permanently elevated level of general phosphorus (0.15-0.27 mg/dm3) and ammonium acid (0.16-0.27 mg/dm3), which degraded the quality of life for ichthyofauna inhabiting the lake.