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    Wyświetlanie 1-13 z 13
    Tytuł:
    Hybrid layer type CR/LPC
    Autorzy:
    Dybowski, K.
    Kowalczyk, P.
    Januszewicz, B.
    Batory, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/102424.pdf
    Data publikacji:
    2017
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    hybrid layer
    thermo-chemical treatment
    metallization
    diffusion
    Opis:
    Application of metal coatings and the carburized layer are widely known and readily used for various elements, depending on the application. Metal coatings based on chromium are used in order to increase resistance to wear, corrosion and erosion. The coatings applied by different methods have a significant drawback - they are not well related with the substratum, so there is a risk of cracking or flaking. Any discrepancies and flaws disqualify such a way as to protect the surface. Carburizing processes will be carried out, primarily in order to increase the hardness of the surface layer while maintaining a ductile core of the object. It is likely that the combination of these treatments will provide to increase the hardness of the material. The behavior of the proper order to create hybrid layer ensures the continuity of the resulting layer and its good connection with the steel. The paper presents a hybrid layer consisting of the deposited chrome and PVD in the next stage of low pressure carburizing. Conducted process allows chromium diffusion into the material, the enrichment of the steel and to ensure the continuity of the layer.
    Źródło:
    Advances in Science and Technology. Research Journal; 2017, 11, 2; 23-27
    2299-8624
    Pojawia się w:
    Advances in Science and Technology. Research Journal
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The influence of workpiece speed on microhardness and residual stresses in vacuum-carburised 20MnCr5 steel using the single-piece flow method
    Autorzy:
    Sawicki, J.
    Januszewicz, B.
    Sikora, M.
    Witkowski, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/24200559.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    surface grinding
    microhardness
    residual stress
    vacuum carburising
    single-piece flow
    szlifowanie powierzchni
    mikrotwardość
    naprężenie szczątkowe
    nawęglanie próżniowe
    przepływ jednoczęściowy
    Opis:
    Purpose: To determine the impact of selected conditions of abrasive treatment on the value and distribution of microhardness and residual stresses in layers carburised by a continuous single-piece flow method. Design/methodology/approach: Reference pieces were low pressure carburised at 920°C and then heat-treated in a 4D Quench heat treatment chamber at a pressure of 7 bar and tempered at 190ºC for 3 hours. In the next stage, samples were ground at various vw piece speeds, introducing grinding fluid into the cutting zone using the WET spraying method or using the MQL method at a minimum flow rate. The distribution of microhardness and residual stresses generated in the technological outer layer of the pieces following heat and chemical treatment and the grinding process was measured. Findings: Results of the tests indicated that the vw piece speed and method used to supply cooling and lubricating fluid to the grinding zone had an impact on selected parameters of the technological outer layer of flat samples made of 20MnCr5 steel. The process of grinding using an electrocorundum grinding wheel results in a deterioration of residual stresses in the material. For each of the three analysed vw piece speeds, reduced changes in material microhardness prior to cutting occur in the outer layer of samples ground using GF supplied at a minimum flow rate using the MQL method. Research limitations/implications: Environmental considerations and having to conform to increasingly stringent regulations related to environmental protection and employee safety motivate researchers and businesses to entirely eliminate or reduce the use of grinding fluids in the grinding process and, therefore, to optimise grinding technology. Practical implications: Modern manufacturing industry requires the grinding process, which follows heat and chemical treatment, to be performed with the highest possible efficiency. However, retaining high parameters of the technological outer layer in comparison to the sample material following vacuum carburisation (before grinding) is extremely difficult. An optimised configuration of parameters of the grinding process and method of supplying grinding fluids enables meeting the current and future high expectations of the industry in this regard. Originality/value: The tests have enabled us to determine the impact of the applied vw workpiece speed and method of supplying grinding fluid on microhardness and residual stresses. Generally speaking, grinding with an electrocorundum grinding wheel results in a deterioration of residual stresses. For both methods of supplying GF (WET and MQL), the distribution of microhardness in the material of the samples ground with the highest workpiece speed (18.0 m/min) indicated no significant differences with regard to the distribution of microhardness in the material of the samples following heat and chemical treatment.
    Źródło:
    Archives of Materials Science and Engineering; 2022, 115, 2; 66--75
    1897-2764
    Pojawia się w:
    Archives of Materials Science and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of the impact of double shot peening on the value of roughness parameter and distribution of stresses in the RSA 501 alloy
    Autorzy:
    Byczkowska, P.
    Sawicki, J.
    Januszewicz, B.
    Stegliński, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/957816.pdf
    Data publikacji:
    2017
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    shot peening
    double shot peening
    surface treatment
    residual stresses
    roughness
    Opis:
    The bead blasting process is widespread in both the automotive and aerospace industry and is performed in order to improve the fatigue strength of various components. Bead blasting is a cold plastic forming process during which the surface of the material processed is hit by small, hard particles consisting of steel pellets, bearing balls or glass beads. It increases the hardness of the outer layer and establishes compression stresses inside it, which is why this processing is often used to improve fatigue strength. Contrary to other peening methods, bead blasting does not result in a reduction in the height of the processed surface’s unevenness in most cases. Shot peening changes the residual tensile stresses into residual compression stresses, thanks to which, the lifetime of the parts processed is extended and their carrying capacity is increased. The double shot peening process proposed by the authors consists in a two-stage bead blasting process. The first stage consists in blasting with round cast steel pellets, pellets cut from wire or cast iron pellets. During the second stage the same samples underwent glass bead blasting. The tests conducted on the RSA-501 aluminum alloy indicate that as a result of the processing medium’s impact in the form of glass beads or pellets of different diameter and shape, a permanent plastic deformation of the material surface occurs. On the basis of the obtained results it is possible to infer that the choice of parameters of both conventional shot peening and the double shot peening determine the impact thereof on the material’s mechanical properties. Thanks to the application of the double shot peening process there is a noticeable decrease in value of the Ra parameter, by about 40% on average. When analyzing the compressive stress results it is possible to state that after the first blasting process the value of stress was increasing when moving deeply into the sample from its surface, while after the glass bead blasting the value of compressive stress was significantly higher already near the surface. Double shot peening results in an increase in the value of compressive stresses by 40-50% when compared to conventional blasting.
    Źródło:
    Advances in Science and Technology. Research Journal; 2017, 11, 3; 1-9
    2299-8624
    Pojawia się w:
    Advances in Science and Technology. Research Journal
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of Single-Stage and Duplex Shot Peening on Surface Roughness and Residual Stresses in Al Mg5 Mn1 Sc0,8 Zr0,4 Alloy
    Autorzy:
    Byczkowska, P.
    Sawicki, J.
    Januszewicz, B.
    Stegliński, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/353741.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    shot peening
    double shot peening
    residual stresses
    roughness
    Opis:
    Conventional shot peening (SP) is cheap surface treatment widely used to enhance fatigue life of mechanical components [3,4]. Basically, it is shooting small particles (shots) on the surface of the sample. However, the process itself is so complex that a lot of companies are not able to optimally employ it due to the amount of parameters that must be controlled all at the same time. The duplex process consists in two stages of shot-peening treatment. The first one consist of shot-peening with spherical cast steel shots or cut wire shots. During the second stage the samples processed in stage one were subject to shot-peening with glass beads. In this work, RSA-501 aluminium alloy was shot peened using shots of different material and diameter and tested using a measurement of residual stresses and surface roughness. Tests and studies conducted so far on RSA-501 aluminium alloy demonstrate that bombardment by a treatment medium in the form of glass beads or shots of various shapes and diameters induces permanent plastic deformation of the surface layer. The roughness achieved after the shot-peening process was determined for each treatment medium. The largest value of Ra parameter was achieved for cut wire shots and this result is consistent with the above-mentioned theoretical knowledge. This medium is the most aggressive one to the surface being treated primarily due to the sharp edges of shots. The duplex process was successful in obtaining higher values of compressive stresses in surface layer than values achievable in conventional single-stage shot peening process.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 1; 505-511
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An analysis of crystallographic texture and residual stresses of aluminium alloy RSA-501 after selected processes of twist extrusion (TE)
    Autorzy:
    Byczkowska, P.
    Sawicki, J.
    Adamczyk-Cieślak, B.
    Januszewicz, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/24200596.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    severe plastic deformation
    twist extrusion
    aluminium
    FEM
    crystallographic texture
    stress
    hardness
    odkształcenie plastyczne
    wyciskanie skrętne
    tekstura krystalograficzna
    naprężenie
    twardość
    Opis:
    Purpose: This study presents the residual stress analysis for the twist extrusion (TE) process after the experiment and numerical simulation and the analysis of the crystallographic texture changes and changes in hardness before and after the TE process for an RSA-501 aluminium alloy (Al; Mg5%; Mn1.5%; Sc0.8%; Zr0.4%). Design/methodology/approach: Crystallographic textures were obtained with the PANAlytical Empyrean X-ray diffractometer. The stresses were measured by applying the X-ray method with the use of using the PROTO iXRD diffractometer. Findings: The use of severe plastic deformation processes in the mass of the material leads to a significant change difference in the stress distribution in the workpiece and a change in texture compared to the reference material. The stress distribution in the sample cross-section and stress values varied and depended on the stage of the twisting process to which the surface was subjected. The highest stress (about 600 MPa) appears at the peaks of the front surface when exiting the twist area die TE. Higher stress values at the edges of the specimen are caused by friction (deformation) of the material against the die surface. The TE process strengthened – the highest crystallographic texture background level was 49%. Practical implications: The conducted tests and the obtained results allow the determination of the process parameters and critical areas of the sample by carrying out a numerical simulation. Originality/value: Microhardness increases due to the TE process and the largest values were observed at the edges. This phenomenon is confirmed by the numerical simulation results presented in this paper.
    Źródło:
    Archives of Materials Science and Engineering; 2022, 118, 1; 5--28
    1897-2764
    Pojawia się w:
    Archives of Materials Science and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ atmosfery stosowanej w segmencie dyfuzji w procesach FineLPN na właściwości warstw azotowanych na stalach HS6-5-2 oraz X37CrMo51
    Effects of the atmosphere used during the diffusion segment of the Fi-neLPN technology on the properties of the nitrided layers of steels HS6- 5-2 and X37CrMo51
    Autorzy:
    Kula, P.
    Januszewicz, B.
    Wołowiec, E.
    Rzepkowski, A.
    Pietrasik, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/109128.pdf
    Data publikacji:
    2013
    Wydawca:
    AXIS MEDIA
    Tematy:
    azotowanie niskociśnieniowe
    FineLPN
    stal narzędziowa
    stal szybkotnąca
    piec próżniowy
    obróbka cieplna stali
    dyfuzja
    low pressure nitriding
    tool steel
    high-speed steel
    vacuum furnace
    diffusion
    steel heat treatment
    Opis:
    W artykule przedstawiono badania nad opracowaniem modelu fizycznego wielosegmentowego azotowania niskociśnieniowego o strukturze procesu "boost-diffusion". Opracowany model umożliwi przeprowadzenie obróbki cieplnej i niskociśnieniowego azotowania stali narzędziowej i szybkotnącej w piecu próżniowym.
    The article discusses studies that have j sought to create a physical model of the boost-diffusion multi-segment low-pressure nitriding process. The model would be subsequently used to perform heat treatment and low-pressure nitriding of tool steels and high speed steels in a vacuum furnace.
    Źródło:
    Piece Przemysłowe & Kotły; 2013, 9-10; 42-45
    2082-9833
    Pojawia się w:
    Piece Przemysłowe & Kotły
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Effect of Non-Metallic Inclusions Formed as a Result of Deoxidation on the Fatigue Strength of 15CrNi6 and 16MnCr5 Steel
    Autorzy:
    Lipa, S.
    Sawicki, J.
    Dybowski, K.
    Pietrasik, R.
    Januszewicz, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/353324.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    fatigue strength
    non-metallic inclusions
    thermo-chemical treatment
    Opis:
    This paper presents the findings of fatigue strength tests of 15CrNi6 steel following low-pressure carburizing and oil quenching, subjected to cycles of one-sided three-point bending. The fatigue fractures were compared with the results of fatigue strength studies of 16MnCr5 steel following low-pressure carburizing and nitrogen quenching. The fatigue tests for 16MnCr5 steel were conducted as part of a high-cycle resonance test, with a pendular bending load. The study also involved an analysis of the effects on non-metallic inclusions in the structure on the mechanism of fatigue destruction. The inclusions were found to initiate fatigue cracks. In both cases, a similar method of a fatigue fissure initiation was observed, independent of the study method or specimen material.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 3; 1345-1350
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of grinding conditions of gears made of 20MnCr5 steel after single-piece flow heat treatment on the condition of the surface layer of the tooth working surface
    Autorzy:
    Stachurski, W.
    Janica, J.
    Januszewicz, B.
    Pawłowski, W.
    Sawicki, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/24200636.pdf
    Data publikacji:
    2023
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    thermo-chemical treatment
    vacuum carburizing
    single-piece flow method
    gear grinding
    technological surface layer
    obróbka cieplno-chemiczna
    nawęglanie próżniowe
    jednoczęściowa metoda przepływowa
    szlifowanie kół zębatych
    technologiczna warstwa wierzchnia
    Opis:
    Purpose: The paper investigated the effect of selected processing conditions during gear grinding on the value and distribution of microhardness and residual stress formed in the technological surface layer of gears after thermochemical treatment (TCT) conducted by a continuous single-piece flow method. Design/methodology/approach: The gears were carburised with LPC at 920°C, then quenched in a 4D Quenching chamber at 7 bar and tempered at 190ºC for 3 hours. In the next step, the working surfaces of the gear teeth were ground by supplying grinding fluid (GF) to the grinding zone using the WET method and the MQL method with a minimum amount. Measurements were made on the distribution of microhardness and residual stress formed in the technological surface layer of gears after thermochemical treatment and after the grinding process. Findings: The results of the study showed the influence of workpiece speed vw and the method of delivery to the grinding zone GF on selected parameters describing the condition of the technological surface layer of the teeth of gears made of 20MnCr5 steel. The grinding process with a white aluminium oxide grinding wheel causes deterioration in the material's residual stress state. For each of the three analysed workpiece speeds vw, smaller changes in microhardness with respect to the microhardness of the material before grinding occur in the surface layer of samples ground with GF fed with the MQL method. Similarly, residual stress values are in the area of favourable compressive stresses. Research limitations/implications: Environmental considerations and the need to comply with increasingly stringent environmental protection and worker safety regulations are pushing researchers and entrepreneurs to completely eliminate or reduce the consumption of grinding fluids in the grinding process. Based on the research and analysis carried out in this study, it was concluded that applying minimum GF by the MQL method could be an alternative to the conventional WET method.Practical implications: In sustainable manufacturing, it is extremely important to produce high-quality items while reducing the cost of manufacturing and taking care of the environment and workers' health. This includes the manufacture of gears, a basic component used in gear transmissions in the automotive industry, for example. The research has established that it is possible to use the MQL method, which reduces the amount of GF used when grinding the working surfaces of gear teeth, as an alternative to the conventional WET method. Originality/value: The conducted research was the first to determine the most favourable conditions, in terms of the obtained residual stresses and microhardness, for grinding the working surface of gear teeth using the MQL method.
    Źródło:
    Archives of Materials Science and Engineering; 2023, 120, 2; 60--69
    1897-2764
    Pojawia się w:
    Archives of Materials Science and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An effect of grinding on microhardness and residual stress in 20MnCr5 following single-piece flow low-pressure carburizing
    Autorzy:
    Stachurski, W.
    Krupanek, K.
    Januszewicz, B.
    Rosik, R.
    Wojcik, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/99540.pdf
    Data publikacji:
    2018
    Wydawca:
    Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
    Tematy:
    vacuum carburizing
    single-piece flow
    surface grinding
    microhardness
    residual stress
    Opis:
    The aim of the experiment described in the paper was to determine the effect of selected conditions of abrasive machining on the size and distribution of microhardness and residual stresses developed in the technological surface layer of flat specimens made of 20MnCr5 steel. The specimens were subjected to single-piece flow low-pressure carburizing (LPC) and high-pressure gas quenching (HPGQ) in a 4D Quenching chamber, in order to achieve the effective case depth of ECD=0.4 mm. This was followed by grinding the specimens with Quantum and Vortex alumina grinding wheels made by Norton. Cooling and lubricating liquid were supplied to the grinding zone in both cases by the flood (WET) method and by the minimum quantity lubrication (MQL) method. The measurements for each specimen were made twice - after the thermo-chemical treatment and after the grinding. Microhardness and residual stress was measured by the X-ray method sin2Ψ. The final part of the article provides an analysis of the measurement results and presents conclusions and recommendations for further studies.
    Źródło:
    Journal of Machine Engineering; 2018, 18, 4; 73-85
    1895-7595
    2391-8071
    Pojawia się w:
    Journal of Machine Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synergy of the Plastic Treatment HPT and Shot Peening in Aluminium Alloy Al-Mg-Mn-Sc-Zr
    Autorzy:
    Stegliński, M.
    Byczkowska, P.
    Sawicki, J.
    Kaczmarek, Ł.
    Januszewicz, B.
    Klich, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/355364.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    high-pressure torsion
    shot peening
    numerical analysis
    residual stresses
    fatigue strength
    Opis:
    An improvement in fatigue strength is one of the main factors enabling the use of high-durability Al-Mg-Mn-Sc-Zr alloys in functional components of mobile robots. As part of this study, a computer simulation was carried out using ANSYS LS-DYNA software that involved the hybridization of high pressure torsion (HPT) and shot peening (SP) forming processes. The numerical analysis was aimed at determining residual stresses and strains that affect the durability and stress characteristics of the analyzed Al alloy. Results of the study indicate that tensile stresses of σ = 300 MPa generated as a result of HPT are transformed into a beneficial stress of σ = 25 MPa resulting from plastic strains caused by SP surface treatment.
    Źródło:
    Archives of Metallurgy and Materials; 2016, 61, 2B; 1135-1142
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Pheochromocytoma - the catecholamine dependent hypertension
    Autorzy:
    Januszewicz, W
    Wocial, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/71057.pdf
    Data publikacji:
    1995
    Wydawca:
    Polskie Towarzystwo Fizjologiczne
    Tematy:
    pheochromocytoma
    epinephrine
    catecholamine
    hypertension
    norepinephrine
    endocrine hypertension
    chromaffin tumour
    blood pressure
    Źródło:
    Journal of Physiology and Pharmacology; 1995, 46, 3
    0867-5910
    Pojawia się w:
    Journal of Physiology and Pharmacology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ działalności populacji bobra europejskiego (Castor fiber L.) na roślinność drzewiastą Wigierskiego Parku Narodowego
    Impact of the European beaver (Castor fiber L.) population on the woody vegetation of Wigry National Park
    Autorzy:
    Misiukiewicz, W.
    Gruszczynska, J.
    Grzegrzolka, B.
    Januszewicz, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/844002.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Zootechniczne
    Tematy:
    bobr europejski
    Castor fiber
    preferencje pokarmowe
    rosliny drzewiaste
    drzewa
    krzewy
    zgryzanie
    Wigierski Park Narodowy
    Opis:
    Badania wpływu działalności populacji bobra europejskiego na skład gatunkowy drzewostanów prowadzono na terenie Wigierskiego Parku Narodowego, który jest położony na obszarze północno-wschodniej Polski. Badania prowadzono w drzewostanach występujących nad jeziorem dystroficznym „sucharem”, brzegiem rzeki i rowu melioracyjnego oraz w środowisku śródpolnym. Fakt zasiedlenia przez bobry wyznaczonych do obserwacji obszarów potwierdzono przy wykorzystaniu kamery termowizyjnej ThermoPro TP8 z niechłodzoną matrycą mikrobolometryczną 384x288 pikseli. Na każdej powierzchni badawczej wyznaczono po pięć transektów czterometrowej szerokości, na których przeprowadzono pomiary pięciu klas uszkodzeń pni oraz dwóch klas średnicy pni. Zbadano sezonowe preferencje bobrów w zgryzaniu poszczególnych gatunków roślin drzewiastych. Analiza przeprowadzona została dla każdego z czterech środowisk. Wyniki badań świadczą, że po średnio 15-letniej obecności bobrów w obszarach, które były rotacyjnie zasiedlane i opuszczane przez zwierzęta, udział zdrowych roślin drzewiastych wynosi 73,09%. Spośród 17 gatunków roślin drzewiastych do najchętniej ścinanych należały wierzba szara (25,19%) i leszczyna pospolita (32,36%). Analiza wykazała, że największym zainteresowaniem bobrów cieszyły się rośliny o średnicy pnia <10 cm (98,28%). Najbardziej eksploatowane było środowisko rzeczne oraz rowu melioracyjnego, gdzie bobry ścięły, odpowiednio 40,27% oraz 42,70% dostępnych roślin drzewiastych.
    Research on the impact of the European beaver population on the species composition of forest stands was conducted in Wigry National Park, situated in north-eastern Poland. The study was conducted in forest stands on a dystrophic lake of the ‘suchar’ type, i.e. a dystrophic lake with high acidity and low species diversity of vegetation on its shores, on the banks of a river and a drainage ditch, and in a field environment. A ThermoPro TP8 thermal imaging camera with an uncooled microbolometer matrix of 384x288 pixels was used to confirm that the designated observation areas were inhabited by beavers. In each research area five transects four metres in width were established, where measurements were taken of five classes of trunk damage and two classes of trunk diameter. We examined the seasonal preferences of beavers in gnawing particular species of woody plants. An analysis was performed for each environment. The results indicate that after an average 15-year presence of beavers in the areas, which they inhabited rotationally, the percentage of healthy woody plants was 73.09%. Of the 17 species of woody plants, the ones most readily cut down by the beavers were grey willow (25.19%) and common hazel (32.36%). The analysis demonstrated that the rodents showed the greatest interest in plants with a trunk diameter of <10 cm (98.28%). The river and drainage ditch were the most exploited environments; here beavers cut down 40.27% and 42.70%, respectively, of the available woody plants.
    Źródło:
    Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego; 2016, 12, 3
    1733-7305
    Pojawia się w:
    Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Using two methods for plant material preparation in order to determine the content of bioelements in red cabbage (brassica oleracea l. var. capitata l. f. rubra)
    Użycie dwóch metod przygotowania materiału roślinnego do określenia zawartości biopierwiastków w kapuście czerwonej (brassica oleracea l. var. capitata l. f. rubra)
    Autorzy:
    Pliszka, B.
    Huszcza-Ciolkowska, G.
    Mieleszko, E.
    Wrblewska-Wierzbicka, B.
    Januszewicz, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/14069.pdf
    Data publikacji:
    2011
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
    Opis:
    Mineral components (bioelements) are one of the five major groups of nutrients in human diet, next to proteins, lipids, carbohydrates and vitamins. The required daily amounts per capita are over 100 mg of macroelements and less than 100 mg of microelements. Every industrial processing technology applied to vegetable produce causes precipitation of bioelements and consequently undesirable losses of these components. The purpose of this study has been to analyze the content of bioelements (Ca, Mg, Zn, and Fe) determined in homogenizates and extracts from three red cabbage cultivars (Koda, Haco POL, Kissendrup SWE). Correlation coefficients served to assess the concordance between the plant material preparation methods used for determination of bioelements. The correlation between the content of Mg versus Ca and Zn versus Fe in edible parts of cabbage (homogenizates) compared to the levels of these metals in red cabbage extracts was tested. Two methods for the preparation of plant material for chemical analyses were used: homogenization and extraction. Citric acid solution of the concentration of 0.1 mol dm–3 was used for extraction. The content of bioelements was determined using atomic absorption spectrophotometry (AAS). The content of Ca and Zn in red cabbage depended on the method applied to the plant material preparation, i.e. homogenization or extraction. The content of Mg and Fe depended on the cabbage cultivars. Irrespective of the plant material preparation methods, the red cabbage cultivars Kissendrup SWE and Koda contained the highest average levels of Ca, Mg, Zn, and Fe, while the lowest ones were determined in cv. Haco POL. High correlation obtained for Mg enables us to convert the content of this element in homogenizates (A) into its content of extracts (B) – conversion factor A:B = 0.9. Positive and highly significant correlations were found between the content of the bioelements: Ca and Mg, Zn and Fe in cabbage homogenizates.
    Składniki mineralne (biopierwiastki) z żywieniowego punktu widzenia stanowią jedną z pięciu podstawowych grup składników odżywczych dla człowieka, oprócz białek, tłuszczów, węglowodanów i witamin. Dzienne zapotrzebowanie na składniki mineralne dla 1 osoby wynosi: makroelementy powyżej 100 mg i mikroelementy poniżej 100 mg. Każda obróbka przemysłowa produktów roślinnych powoduje wytrącenie się biopierwiastków, i w konsekwencji niepożądane straty tych składników. Celem pracy było zbadanie zawartości biopierwiastków (Ca, Mg, Zn i Fe) oznaczonych w homogenizatach i w ekstraktach z trzech odmian kapusty czerwonej (Koda, Haco POL, Kissendrup SWE). Oceniono zgodność zastosowanych metod przygotowania materiału roślinnego do oznaczania biopierwiastków za pomocą współczynnika korelacji. Poszukiwano korelacji między zawartością Mg a Ca oraz Zn i Fe w części jadalnej kapusty czerwonej (homogenizatach) i w otrzymanych z niej ekstraktach. Zastosowano dwie metody przygotowania materiału roślinnego do analiz chemicznych: homogenizację i ekstrakcję. Do ekstrakcji zastosowano roztwór kwasu cytrynowego o stężeniu 0.1 mol dm–3. Zawartość biopierwiastków oznaczono metodą atomowej spektrometrii absorpcyjnej. Zawartość Ca i Zn w kapuście czerwonej zależała od metody przygotowania materiału roślinnego do badań, zawartość Mg i Fe – od odmiany kapusty. Niezależnie od metody przygotowania materiału roślinnego, odmiany kapusty czerwonej Kissendrup SWE i Koda zawiera ły najwięcej Ca, Mg, Zn i Fe, a najmniej odmiana Haco POL. Wysoka korelacja w przypadku Mg daje możliwość przeliczenia zawartości tego pierwiastka w homogenizatach (A) na zawartość w ekstraktach (B) – przelicznik A:B = 0.9. Stwierdzono dodatnią i wysoce istotną zależność między zawartością biopierwiastków Ca i Mg, Zn i Fe w homogenizatach z kapusty.
    Źródło:
    Journal of Elementology; 2011, 16, 3
    1644-2296
    Pojawia się w:
    Journal of Elementology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-13 z 13

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