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Wyświetlanie 1-4 z 4
Tytuł:
Influence of pick layouts on the performance of bolter miner cutting head
Autorzy:
Qiao, S.
Wang, A. L.
Xia, Y. M.
Liu, Z. Z.
Liu, J. S.
Yang, M.
Powiązania:
https://bibliotekanauki.pl/articles/88893.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
optimum
pick layout
bolter miner
FEM
coal-rock cutting
load fluctuation
Opis:
A bolter miner is a new type of mining machinery with cutting and anchoring functions. In order to study the best pick layout of bolter miner cutting head. Based on the constitutive relation of Holmquist-Johnson-Cook (HJC), three simulation models of different cutting heads were established, and the whole crushing process of coal-rock was simulated by finite element method (FEM). The influence of the cutting head on the cutting performance under the condition of different rotational speeds and pick layouts was intensively studied. The results show that the relationship of load fluctuation coefficient among the three pick layouts is as follows: sequential type > hybrid type I > checkerboard type. The circumferential pick layouts can reduce the load fluctuation coefficient of cutting head. The rotational speed from 20 to 40 r/min, the torque linearly decreases with the increase of rotational speed. The rota-tional speed increases from 40 to 50 r/min, the cutting torque is relatively stable. The specific energy of chessboard type is relatively higher than the other three cutting heads. The difference of specific energy between sequential type and hybrid type I is not more than 5.5%, and the reality of the simulation is verified by cutting experiments. The results were successfully applied to the first shield type bolter miner in China.
Źródło:
Mining Science; 2018, 25; 147-160
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite element analysis of load characteristic of shield bolter miner cutting head under complex coal seam condition
Autorzy:
Qiao, S.
Xia, Y. M.
Liu, Z. Z.
Liu, J. S.
Ning, B.
Wang, A. L.
Powiązania:
https://bibliotekanauki.pl/articles/89071.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
complex coal seam
shield bolter miner
load characteristic
specific energy
load fluctuation
Opis:
Aiming at the complex conditions of the first shielded bolter miner in the actual work, the mechanical model of bolter miner cutting head was established. Based on cutting mechanism of the conical pick and the cutting head, the cutting head load and torque analysis model under complex coal seam were established. The dynamic characteristics of load and torque in the process of cutting head are analyzed under three different working conditions of cutting roof-coal layers, coal-floor layers and coal seam by finite element method. The results show that when the damage variable D=1, the coal-rock completely lacks the bearing capacity, and it forms arc-shaped crushing groove on the coal-rock. The large difference of torque between roof-coal layers and the roof-coal layers in the conical pick is 112 Nm, which indicates that the cutting head has the best performance with cutting the coal seam first and then cutting the rock. In the process of excavation, the load fluctuation coefficient of cutting the coal-floor layers and roof-coal layers is about 1.2 times of that of the coal seam. The results can provide a reference for the efficient cutting and performance evaluation of the bolter miner.
Źródło:
Mining Science; 2017, 24; 85-97
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ecophysiological aspects of the interaction between Cameraria ohridella and Guignardia aesculi on Aesculus hippocastanum
Autorzy:
Jagiełło, Radosław
Baraniak, Edward
Karolewski, Piotr
Łakomy, Piotr
Behnke-Borowczyk, Jolanta
Walczak, Urszula
Giertych, Marian J.
Powiązania:
https://bibliotekanauki.pl/articles/956794.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
plant growth
foliage damage
leaf blotch
leaf miner
plant defence
Opis:
Popular in the urban environment is the horse chestnut, Aesculus hippocastanum which is suffering mainly due to the feeding of the horse chestnut leaf miner (Cameraria ohridella). The harmfulness of this pest is well recognized. Not much attention was put in discovering the interaction of this insect with the fungal pathogen Guignardia aesuli, the agent of leaf blotch. Host plant mediation in this particular insect-plant pathogen interaction is crucial for understanding the complexity of the horse chestnut’s current and future situation. Recognising the response of the host plant for separated and simultaneous colonisation by insect and fungus was the aim of this study. Leaf damage dynamics and phenolic compounds content (total soluble phenolic compounds – TPh, and condensed tannins – CT), and stem volume increment (SVI) of the horse chestnut saplings was considered and their relationship identified. The main hypothesis was that insect feeding and fungal infection when separated elicit a similar pattern in defence response of the host but this defence response is different when they both coexist on the same plant. Basing on crown projection area photographs sequence, foliage damage dynamics was assessed (Richard’s growth model) and protocol developed. Measurements of stem volume were performed sequentially to indicate potential growth response. Through this study, it was identified that the content of phenolic compounds in leaves was higher when both pests colonized saplings in comparison with those where saplings were infested by one biotic factor. It is also documented that foliage damage dynamics was higher when only the fungal pathogen attacked plants than when it was infected by both pests. A trade-off was identified between growth and secondary metabolism. Leaf damage affected stem volume increment only in the late summer, when a high level of defoliation was observed. Simultaneous infestation by fungal and insect agents made unfavourable conditions rather for the former. How this interaction affects the latter is not covered by our results and still remains undiscovered.
Źródło:
Dendrobiology; 2017, 78; 146-156
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sześć rzeźb z serii górników manufaktury porcelany w Miśni ze zbiorów Muzeum Żup Krakowskich Wieliczka – historia i badania
Six sculptures of the miners – series made in the Meissen porcelain manufactory in the collection of the Cracow Saltworks Museum in Wieliczka – history and research
Autorzy:
Ochniak-Dudek, Klementyna
Lisińska-Kopacz, Anna
Wilkosz, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2054994.pdf
Data publikacji:
2021-10-10
Wydawca:
Muzeum Żup Krakowskich Wieliczka
Tematy:
porcelana
rzeźba górnika
Miśnia
J. J. Kaendler
1750 r.
XVIII w.
XIX w.
spektroskopia XRF
rentgenografia
fotografia analityczna
miner sculpture
Meissen
1750
18th century
19th century
X-ray fluorescence spectroscopy
X-ray radiography
analytical photography
porcelain
Opis:
Artykuł dotyczy zespołu sześciu porcelanowych figurek (wys. ok. 20 cm) z Miśni, od 2019 r. znajdujących się w zbiorach Muzeum Żup Krakowskich w Wieliczce. Rzeźby górników pochodzą ze znanej i cenionej serii, wymodelowanej przez Johanna Joachima Kaendlera i Petera Reinicke ok. połowy XVIII w. Opracowanie kompleksowo przedstawia historię i stan zachowania rzeźb. Pierwsza część artykułu – historyczno-artystyczna – stanowi szczegółowe studium opisujące wzory i historię obiektów na tle innych realizacji. Wnikliwie została udokumentowana kwerenda przeprowadzona przez Klementynę Ochniak-Dudek w zakresie literatury i istniejących kolekcji porcelany miśnieńskiej, a także dziejów manufaktury. Druga część artykułu prezentuje wyniki badań fizykochemicznych rzeźb, które dr Anna Klisińska-Kopacz i dr Tomasz Wilkosz wykonali w Laboratorium Analiz i Nieniszczących Badań Obiektów Zabytkowych Muzeum Narodowego w Krakowie. Wnioski autorów istotnie wzbogacają wiedzę o stanie zachowania i pozwalają rozstrzygnąć datowanie obiektów, jak również ostatecznie potwierdzają proweniencję czterech rzeźb z przedwojennej kolekcji Gustawa von Klemperera w Dreźnie. Ta część artykułu ma charakter pionierski na polskim gruncie, gdzie analityczne badania porcelany przeprowadzane są rzadko, a ich publikacje w zasadzie nie występują. Opracowanie muzealnych rzeźb o tematyce górniczej poszerza wiedzę z zakresu historii miśnieńskiej porcelany.
The article concerns a set of six porcelain figurines (approx. 20 cm high) from Meissen, since 2019 in the collection of the Cracow Saltworks Museum in Wieliczka. The sculptures presenting miners come from a well-known and respected series, modelled by Johann Joachim Kaendler and Peter Reinicke around the mid-18th century. The study comprehensively presents the history and condition of the sculptures. The first part of the article – a historical and artistic one – is a detailed study presenting the patterns and history of the exhibits compared to other implementations. The query carried out by Klementyna Ochniak-Dudek in the field of literature and existing collections of Meissen porcelain, as well as the history of the manufactory has been thoroughly documented. The second part of the article presents the results of physicochemical studies of sculptures that Anna Klisińska-Kopacz, PhD and Tomasz Wilkosz, PhD carried out at the Laboratory of Analysis and Nondestructive Investigation of Heritage Objects at the National Museum in Krakow. The authors’ conclusions significantly enrich the knowledge of the state of preservation, and allow for specification of the dating of objects, as well as finally confirm the provenance of four sculptures from the pre-war collection of Gustav Klemperer in Dresden. This part of the article is pioneering in Poland, where analytical porcelain research is rarely carried out and its publications are practically non-existent. The development of museum mining-related sculptures broadens the knowledge of the history of Meissen porcelain.
Źródło:
Studia i Materiały do Dziejów Żup Solnych w Polsce; 2021, XXXV, 1; 300-389
0137-530X
Pojawia się w:
Studia i Materiały do Dziejów Żup Solnych w Polsce
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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