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Number of results: 96
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Abstract

The article presents the results of studies on the efficacy of water desalination (i.e. Elimination of NaCl ions from the solution) using graphene-polyamide composite membranes. The membrane used for filtration consists of a monolayer of polycrystalline graphene on a porous polyamide carrier support (nylon 66). The degree of desalination for an aqueous NaCl solution percolated through the membrane was 18%. In the future this type of membrane may replace the currently used reverse osmosis membranes.
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Abstract

In this work, vacuum hot pressed Ni-Mn-Sn-In Heusler alloys with different concentration of In (0, 2 and 4 at.%), were investigated. The magneto-structural behaviour and microstructure dependencies on chemical composition and on heat treatment were examined. It was found that the martensite start transformation temperature increases with growing In content and to a lesser extent with increasing temperature of heat treatment. The high energy X-ray synchrotron radiation results, demonstrated that both chemical composition as well as temperature of heat treatment slightly modified the crystal structures of the studied alloys. Microstructural investigation performed by transmission electron microscopy confirmed chemical composition and crystal structure changes in the alloys.
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Abstract

Strained layer InGaAs/GaAs SCH SQW (Separate Confinement Heterostructure Single Quantum Well) lasers were grown by Molecular Beam Epitaxy (MBE). Highly reliable CW (continuous wave) 980-nm, broad contact, pump lasers were fabricated in stripe geometry using Schottky isolation and ridge waveguide construction. Threshold current densities of the order of Jth ≈ 280 A/cm2 (for the resonator length L = 700 um) and differential efficiency η= 0.40 W/A (41%) from one mirror were obtained. The record wall-plug efficiency for AR/HR coated devices was equal to 54%. Theoretical estimations of above parameters, obtained by numerical modelling of devices were Jth ≈ 210 A/cm and η = 0.47 W/A from one mirror, respectively. Degradation studies revealed that uncoated and AR/HR coated devices did not show any appreciable degradation after 1500 hrs of CW operation at 35oC heat sink temperature at the constant optical power (50 mW) conditions.
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Abstract

The article presents an ecological characterization of thrips caught in Moericke traps in the Botanical Garden in Lublin. The objective of the research was to study the species composition and abundance of thrips in a man-made environment, where alongside native plants there are also trees and bushes brought in from other parts of the world. A total of 396 adult Thysanoptera individuals belonging to 39 species were caught. This is 17.2% of the thrip fauna in Poland. Among the individuals collected there were 10 dendrophilous species and 3 mycophagous species associated with tree bark and living in rotting wood. This is 25% of the Thysanoptera occurring in Poland with these food preferences. The trap method chosen is effective at catching thrips appearing in the spring and early summer, i.e. Taeniothrips inconsequens, Thrips minutissimus, Oxythrips ajugae and O. bicolor, as well as deeply hidden species that are difficult to capture using other methods. Using the Moericke trap method we collected four species rarely recorded in Poland.
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Abstract

In two fish ponds in Lasy Janowskie Landscape Park 48 water mite species were caught. In the pond Momoty Duże, situated in the Lasy Janowskie reserve, more species (38), higher species diversity (3.88), and a larger share of lake fauna (33.2%) were observed than in Momoty Małe (33, 3.67 and 22.6% respectively). In the combined collected material small water body species were dominant (70.6%). Similarity between the Hydrachnidia assemblages of the two ponds was 50.1%. The large number of species and individuals caught and the high values for the species diversity index confirm the significant role of fish ponds as a habitat for water mites. A characteristic trait of the ponds was the very small percentage of vernal species and of tyrphobiontic and tyrphophilic species. Although more species and a larger share of lake fauna were found in the pond situated in the reserve (Momoty Duże) than in the pond outside the reserve (Momoty Małe), the differences in the structure of the fauna were slight. The lack of pronounced differences between the two ponds was due to their similar habitat characteristics and similar use.
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Abstract

The aim of the study was to specify the current status and direction of transformations of leaf beetle assemblages taking part in the rapid process of succession of vegetation towards the types of forest communities occurring in the Krzemionki Opatowskie reserve. At five sampling sites (in five plant associations) 30 species of Chrysomelidae were recorded. Five typical forest species (Chrysomela populi, Pyrrhalta viburni, Calomicrus pinicola, Altica brevicollis and Cryp-tocephalus labiatus) accounted for 16.67% of the number of species and 12.85% of the number of individuals caught in the reserve. The forest association richest in species (18) was Querco ro-boris-Pinetum (Que_Pin). This was followed by Tilio-Carpinetum association (Til_Car, 15 spp.), and then a mosaic of Tilio-Carpinetum and Querco roboris-Pinetum (Til_Car/Que_Pin), and Peucedano-Pinetum (Peu_Pin) (11 spp. each). The fewest number of species (10) were noted in Potentillo albae-Quercetum (Pot_Que). The most similar were the fauna of Potentillo albae--Quercetum (Pot_Que) and Querco roboris-Pinetum (Que_Pin) (55.08% similarity). The most distinct was the fauna of Peucedano-Pinetum (Peu_Pin). We can conclude that the structure of the leaf beetle assemblages in the forest associations studied in the reserve is at present an adaptive mixture of faunas characteristic of all the intermediate successional stages of vegetation, changing in this area in a relatively short time. The considerable diversity of fauna is the result of an ‘eco-tone in time’, i.e. the continuous presence of open-land species, which until recently had dominated here, accompanied by forest species characteristic of the current habitat types.
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Abstract

The quantity of deposited metals was determined in the tissues of Cepaea nemoralis, Lumbricus terrestris and Geotrupes stercorarius, as well as in plant and soil samples from two locations characterized by different levels of human impact. The bioaccumulation factor (BAF) of metals in the bodies of these invertebrate taxa occupying the same habitats was compared, in relation to their content in Taraxacum officinale leaves and in the soil. Analysis of the content of metals in the bodies of selected species belonging to different taxonomic groups demonstrates the usefulness of these invertebrates in biomonitoring.
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Abstract

One of the consequences of the dynamic technological development is the rapidly increasing amount of electro-waste (WEEE, e-waste). Because there are no uniform legal regulations regarding the ways of collecting such waste, the separate-collection systems used in various areas are not homogeneous, and they usually also differ in effectiveness. The aim of this study was to evaluate the electro-waste collection system implemented in Lublin (the largest city in Eastern Poland). Taking into account the fact that the reliability of a collection system depends on the degree of its adaptation to the functions it performs, the evaluation consisted in determining how big a problem improper electro-waste segregation was. The article presents the results of a study of the causes of citizens’ failure to properly manage e-waste and indicates what measures should be taken to amend the problem. During two research steps, 347 pieces of e-waste with a total weight of 77.218 kg were found in the analyzed waste samples (0.33% of all samples). This means that the mechanisms of selective e-waste collection still do not work correctly, despite the ten years of Poland’s membership in the EU and implementation of European legislation in this area. The fact that residents throw away electric waste into municipal mixed waste containers poses a serious problem for proper waste management – even if only a part of the e-waste is disposed in this illegal way. This indicates the necessity of improving waste collection (more frequent waste reception, convenient access to e-waste containers, raising public awareness, etc.).
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