12 research outputs found

    Zmechanizowana obudowa nowego typu do pokładów cienkich.

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    Jednym z podstawowych problemów górnictwa podziemnego zarówno w Polsce jak i na świecie jest eksploatacja pokładów cienkich. Zasadniczą przeszkodę w wybieraniu pokładów cienkich stanowią ekstremalnie trudne warunki eksploatacji i obsługi maszyn zmechanizowanego kompleksu ścianowego, które w dużej mierze wynikają z charakterystyki aktualnie stosowanych zmechanizowanych obudów ścianowych. W związku z powyższym w Katedrze Maszyn Górniczych, Przeróbczych i Transportowych AGH w Krakowie podjęto prace badawcze nad opracowaniem nowej konstrukcji sekcji obudowy zmechanizowanej dedykowanej do pracy w pokładach cienkich. W artykule przedstawiono koncepcyjne, wirtualne modele nowej sekcji zmechanizowanej obudowy do pokładów cienkich, a także podstawowe założenia dla układu sterowania obudową. Prace badawcze w tym zakresie zostały zrealizowane w ramach projektu pt. Prace studialne i badawcze nad opracowanie zmechanizowanej obudowy nowego typu do pokładów cienkich dofinansowanego z Narodowego Centrum Badań i Rozwoju (NCBiR)

    Project and test results of new solution for powered roof support for low seams

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    The subject of thin seam exploitation is a complex problem; in reality, it involves several problems such as technical, ergonomic, and economic barriers. They refer mainly to combined longwalls – where a human presence is required at the site; the most important problem is the issue of the limited workspace in longwall roadways. This generates engineering and organizational problems, especially during the launching and removal of the longwall roadways. Having considered the above-mentioned, the Department of Mining, Dressing, and Transport Machines at AGH in Krakow has begun research whose main objective is to develop and test a new structure for a powered support for thin seams. In this paper, virtual models of the new hydraulic roof support and a conception of the structure of a control system were presented as well as the test results of the new construction hydraulic roof support. Research in this field was conducted for the project entitled “Studies of the Development of an Innovative Hydraulic Roof Support for Low Seams”. The project is funded by the National Center of Research and Development (NCBiR)

    Projekt i badania stanowiskowe nowego typu obudowy zmechanizowanej do pokładów cienkich

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    Tematyka eksploatacji pokładów cienkich jest obecnie jednym z głównych obszarów zainteresowań producentów oraz użytkowników zmechanizowanych kompleksów ścianowych. Wynika to z faktu, iż niezależnie od szeregu czynników górniczo-geologicznych, które w różnym stopniu mogą wpływać na możliwości techniczne prowadzenia ścian niskich, kwestia wzrostu koncentracji wydobycia z pokładów cienkich jest powiązana przede wszystkim z konstrukcją odpowiednio przystosowanych do ekstremalnie trudnych warunków maszyn zmechanizowanego kompleksu ścianowego. Szczególnie istotną rolę w tego typu warunkach eksploatacyjnych odgrywają cechy konstrukcyjne obudów zmechanizowanych. W artykule przedstawiono projekt nowej sekcji obudowy zmechanizowanej do pokładów cienkich oraz wyniki badań stanowiskowych z jej udziałem. Prace badawcze w tym zakresie zostały zrealizowane w ramach projektu pt. „Prace studialne i badawcze nad opracowaniem zmechanizowanej obudowy nowego typu do pokładów cienkich” dofinansowanego z Narodowego Centrum Badań i Rozwoju (NCBiR)

    Spatial Pattern of the Mitochondrial and Chloroplast Genetic Variation in Poland as a Result of the Migration of Abies alba Mill. from Different Glacial Refugia

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    Currently, the information on the gene pool of silver fir (Abies alba Mill.) at the northeastern edge of its distribution in Poland is scarce and insufficient. Using the advantage provided by markers with different modes of inheritance, a hypothesis that gene flow via both seeds and pollen contributed to the genetic structure across the entire analyzed region was investigated. The geographic distribution of maternally inherited mitochondrial DNA (mtDNA, nad5-4) and paternally inherited chloroplast DNA (cpDNA, psbC) variation was studied in 81 Polish populations and three reference populations from Ukraine and Romania. The spatial pattern of mtDNA haplotypes (dispersed via seeds) indicated that the Apennine Peninsula was the only maternal glacial refugium for the entire territory of Poland and also the Ukraine no 1 population, whereas the other two populations—Ukraine no 2 and Romania—had the haplotype representing the Balkan origin. By contrast, the cpDNA haplotypes (dispersed via pollen) from all studied Polish and reference populations showed that A. alba colonized the current natural range from two genetically distinct glacial refugia located on the Apennine and Balkan peninsulas. The occurrence of cpDNA haplotypes varied among the studied populations. Additionally, statistical analyses were used to infer the genetic structure of examined populations. Two distinct groups of A. alba populations were identified showing the postglacial geographic distribution of haplotypes of both mtDNA and cpDNA. A. alba is an important ecological and economic component of forest ecosystems in Europe. An understanding of the Holocene history of this species is relevant for planning sustainable forest management, and acquired data can contribute to strategies of conservation and restoration

    Koncepcja układu sterowania sekcją obudowy podporowej do niskich ścian.

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    W artykule przedstawiono koncepcję struktury układu sterowania obudową podporową do niskich ścian. W pierwszej części artykułu przedstawiono konstrukcję obudowy i jej właściwości, sposób jej działania i współdziałania z pozostałymi elementami kombajnowego kompleksu ścianowego. Na podstawie analizy pracy obudowy i kompleksu ścianowego formułowano założenia, ograniczenia oraz wymagania dotyczące układu sterowania obudową. W dalszej części artykułu opisano strukturę układu pomiarowego i sterującego oraz omówiono poszczególne bloki funkcjonalne układu. Prace badawcze w tym zakresie zostały zrealizowane w ramach projektu pt. Prace studialne i badawcze nad opracowaniem zmechanizowanej obudowy nowego typu do pokładów cienkich, dofinansowanego z Narodowego Centrum Badań i Rozwoju (NCBiR)

    Urine 11-Dehydro-Thromboxane B2 in Aspirin-Naive Males with Metabolic Syndrome

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    Urine 11-dehydro-thromboxane B2 (11-dehydro-TXB2), an indirect measure of platelet activity, is elevated in cardiovascular diseases and diabetes. The purpose of our study was to determine whether urine 11-dehydro-TXB2 is elevated in aspirin-naive males with metabolic syndrome (MS) and to determine predictors of 11-dehydro-TXB2 levels. The secondary aim was to evaluate whether these MS patients could be potential candidates for the aspirin-mediated prevention of atherosclerotic cardiovascular diseases (ASCVDs). In 82 males with MS (76 hypertensive), anthropometric measures, urine 11-dehydro-TXB2, platelet count, creatinine, glucose, insulin, estimated insulin resistance, lipid parameters, high-sensitivity C-reactive protein (hs-CRP), adiponectin, homocysteine, and ten-year risk of fatal cardiovascular disease (SCORE) were assessed. Urine 11-dehydro-TXB2 levels were elevated (≥2500 pg/mg creatinine) in two-thirds of patients, including 11 high-risk patients (SCORE ≥ 5%). Homocysteine, adiponectin, hs-CRP, waist-to-hip ratio, and total cholesterol were found to be predictors of urine 11-dehydro-TXB2. In conclusion, there is a high incidence of elevated urine 11-dehydro-TXB2 in males with MS, including in some patients who are at a high or very high risk of ASCVDs. 11-dehydro-TXB2 levels are associated with hyperhomocysteinemia, inflammation, fat distribution, hypercholesterolemia, and adiponectin concentrations. Elevated 11-dehydro-TXB2 levels may support the use of personalised aspirin ASCVD prevention in high-risk males with MS. Giuseppe Patti

    Soil Environment and Fauna Communities in Europe after Afforestation of Post-Agricultural Lands—A Review

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    Afforestation can make an important contribution mitigating the effects of changing climate and provide structural and functional benefits. Afforestation also provides challenges for forest managers connected with past land-use history; therefore, there is an urgent need to summarize knowledge about such habitats and point out the gaps in knowledge for planning future studies. Although post-agricultural forests cover a large forest area in Europe, our understanding of the mechanisms governing the below-ground environment is still poor, especially when soil fauna is considered. In this study, we revised knowledge about the soil environment and the response of soil fauna to afforestation on former agricultural lands located in Europe based on research articles from the ISI Web of Science database. Data came from various but distinct locations, compared forests with different types of agricultural lands, and presented previous knowledge about soil chemistry and accompanying soil fauna communities. Finally, we selected 15 studies, investigating soil fauna communities on post-agricultural lands. The meta-analysis was based on response ratio (R) for available data, although in many cases the data were incomplete. Results indicated that post-agricultural forests differ from arable lands in reference to soil pH, but not for soil organic matter and carbon content. Different soil animal groups were represented by a similar number of studies: microfauna (seven studies) and mesofauna (nine), whereas macrofauna were represented by five studies. Meta-analysis revealed that the response of soil fauna to afforestation differed between soil fauna size classes. Additionally, in total, 18 tree species, 12 soil types, and 20 soil parameters were provided in the literature but only a few of them were presented in a single study. Future studies should include the impact of microclimate, detailed stand characteristics and soil conditions, which could help to clearly describe the impact of certain tree species growing on certain soil types. In future soil fauna ecological studies, the data should include mean values, standard deviation (SD) and/or standard effort of means (SE) for abundance, species richness, diversity indices and number of collected samples. Providing the above mentioned information will give the broad audience the opportunity to include data in future comparative analyses
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