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Microwave absorption properties of carbonyl iron-based paint coatings for military applications

Defence Technology（防务技术） 2023年第4期22卷 1-9页

作者： Wojciech Przybyl Adam Januszko Norbert Radek Marcin Szczepaniak krzysztof a.bogdanowicz Ireneusz Plebankiewicz Bogusława Szczodrowska Robert Mazurczuk Military Institute of Engineer Technology ul.Obornicka 136Wrocław50-961Poland Kielce University of Technology Faculty of Mechatronics and Mechanical EngineeringAl.1000-lecia P.P.7Kielce25-314Poland

The paper explores the possibilities of using carbonyl iron in the form of a powder for the manufacture of radar-absorbing paints-reducing the radar signature of the objects that they *** attenuation values in the range of 4-18 GHz for various coating thicknesses,ranging from 0.5 to 2.00 mm with 0.5 mm increment,and for different absorber content-75%and 80%,as well as the use of two different binders in the form of epoxy resins with hardeners,were *** the frequency of 18 GHz and a 1.5 mm thick coating with a 75%absorber content,Epidian 112 resin and Saduramid 10/50 hardener used as a binder,and the maximum attenuation level obtained equalled 20.2 d B at 16 ***,the absorber particle size ranging from 3 to 4μm and its higher mass content resulted in achieving the reflection loss above-12 d B in the entire 8-12.5 GHz range for layers between 1-and 1.5 mm *** qualitative assessment of the tested samples in the context of camouflage in the radar range was also performed,using statistical analysis.

关键词： Radar Attenuation Carbonyl iron Coating Camouflage

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On Return Periodof the Largest Historical Flood

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Journal of Geoscience and Environment Protection 2014年第3期2卷 144-152页

作者： Witold G.Strupczewski krzysztof Kochanek Ewa.bogdanowicz Institute of Geophysics Polish Academy of SciencesKsięcia JanuszaWarsawPoland Institute of Meteorology and Water Management PodlesnaWarsawPoland

The use of nonsystematic flood data for statistical purposes depends on reliability of assessment both flood magnitudes and their return period. The earliest known extreme flood year is usually the beginning of the historical record. Even though the magnitudes of historic floods are properly assessed, a problem of their retun periods remains unsolved. Only largest flood (XM) is known during whole historical period and its occurrence carves the mark of the beginning of the historical period and defines its length (L). So, it is a common practice of using the earliest known flood year as the beginning of the record. It means that the L value selected is an empirical estimate of the lower bound on the effective historical length M. The estimation of the return period of XM based on its occurrence, i.e. , gives the severe upward bias. Problem is to estimate the time period (M) representative of the largest observed flood XM. From the discrete uniform distribution with support of the probability of the L position of XM one gets ?which has been taken as the return period of XM and as the effective historical record length. The efficiency of using the largest historical flood (XM) for large quantile estimation (i.e. one with return period T = 100 years) has been assessed using maximum likelihood (ML) method with various length of systematic record (N) and various estimates of historical period length ?com- paring accuracy with the case when only systematic records alone (N) are used. The i-th simula- tion procedure incorporates systematic record and one largest historic flood (XMi) in the period M which appeared in the Li year backward from the end of historical period. The simulation result for selected distributions, values of their parameters, different N and M values are presented in terms of bias (B) and root mean square error (RMSE) of the quantile of interest and widely discussed.

关键词： Flood Frequency Analysis Historical Information Error Analysis Maximum Likelihood Monte Carlo Simulations

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Flood Risk for Embanked Rivers

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Journal of Geoscience and Environment Protection 2014年第3期2卷 135-143页

作者： Ewa.bogdanowicz Witold G.Strupczewski krzysztof Kochanek Iwona Markiewicz Institute of Meteorology and Water Management Podlesna 6101-673 WarsawPoland Institute of Geophysics Polish Academy of SciencesKsiecia Janusza 6401-452 WarsawPoland

Flood frequency analysis (FFA) concentrates on peak flows of flood hydrographs. However, floods that last years devastated large parts of Poland lead us to revision of the views on the assessment of flood risk in Poland. It turned out that it is the prolonged exposure to high water on levees that causes floods, not only the water overflowing the levee crest. This is because, the levees are weakened by water and their disruption occurs when it seems that the danger is over, i.e. after passing culmination. Two main causes of inundation of embanked rivers, namely over-crest flow and wash out of the levees, are combined to assess the total risk of inundation. Therefore the risk of inundation is the total of risk of exceeding embankment crest by flood peak and risk of washout of levees. Hence, while modeling the flood events in addition to the maximum flow one should consider also the duration of high water in a river channel, Analysis of the frequency of annual peak flows based on annual maxima and peaks over threshold is the subject of countless publications. Therefore we will here mainly modeling the duration of high water levels. In the paper the two-component model of flood hydrograph shape i.e. “duration of flooding-discharge- probability of nonexceedance” (DqF), with the methodology of its parameters estimation for stationary case was developed as a completion to the classical FFA with possible extension to non stationary flood regime. The model combined with the technical evaluation of probability of levees breach due to the d-days duration of flow above alarm stage gives the annual probability of inundation caused by the embankment breaking. The results of theoretical research were supplemented by a practical example of the model application to the series for daily flow in the Vistula River in Szczucin. Regardless promising results, this method is still in its infancy despite its great cognitive potential and practical importance. Therefore, we would like to poi

关键词： Flood Frequency Analysis Levee Break Flood Duration Maximum Likelihood Nonstationarity

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Continuous growth through winter correlates with increased resting metabolic rate but does not affect daily energy budgets due to torpor use

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Current Zoology 2021年第2期67卷 131-145页

作者： Jan S.BORATYNSKI Karolina IWINSKA Paulina A.SZAFRANSKA Piotr CHIBOWSKI Wiestaw bogdanowicz Mammal Research Institute Polish Academy of SciencesBiatowiezaPoland Faculty of Biology University of BiatystokBiatystokPoland Faculty of Biology Biological and Chemical Research CentreUniversity of WarsawWarszawaPoland Museum and Institute of Zoology Polish Academy of SciencesWarszawaPoland

Small mammals that are specialists in homeothermic thermoregulation reduce their self-maintenance costs of normothermy to survive the *** contrast,heterothermic ones that are considered generalists in thermoregulation can lower energy expenditure by entering *** is well known that different species vary the use of their strategies to cope with harsh winters in tem-perate zones;however,ittle is still known about the intraspecific variation within populations and the associated external and internal *** hypothesized that yellow-necked mice Apodemus flavicollis decrease their resting metabolic rate(RMR)from autumn to winter,and then increase it during ***,since the alternative for seasonal reduction of RMR could be the develop-ment of heterothermy,we also considered the use of this *** measured body mass(mp),RMR,and body temperature(Tb)of mice during 2 consecutive *** the 1st year,mice decreased whole animal RMR in winter,but did not do so in the 2nd *** mice entered torpor during the 2nd winter,whereas only a few did so during the first *** showed a continuous in-crease of mb,which was steepest during the 2nd *** relationship between RMR and mb var-ied among seasons and years most likely due to different mouse development *** mb gain at the individual level was correlated positively with RMR and *** indicates that high metabolism in winter supports the growth of smaller animals,which use torpor as a compen-satory *** composition of mice hair suggests that in the 1st year they fed mainly on seeds,while in the 2nd,they likely consumed significant amounts of less digestible *** study suggests that the use of specialist or generalist thermoregulatory strategies can differ with environmental variation and associated differences in developmental processes.

关键词： growth rate heterothermy phenotypic fexibiliy resting metabolic rate torpor

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