Earth Pressure Balanced shields are currently the most utilized tunnelling machines throughout around the world. The possibility of using conditioning agents that change the mechanical and hydraulic behaviour of a soil, changing it into a plastic paste and thus permitting soil pressure applications at the tunnel face, is the key point to explain the increasing utilization of this technology. Despite its great importance, not much laboratory researches can be registered on soil conditioning, particularly for cohesionless soils. The conditioning criterion is usually defined on the basis of a trial-and-error procedure developed directly at the job sites. A test that is able to simulate the extraction of soil from the bulk chamber with the screw conveyor inclined upwards, as in real machines, can offer a quantitative indication of the conditioned soil behavior for EPB use. The characteristics of the device and the results obtained on many different types of soil are discussed in order to point out the great importance and quality of results that can be achieved using the proposed test device.
Participants in a conversational exchange may express their viewpoints in a number of ways, or put more precisely, they use various ways of expressing their viewpoints. When employing phrases such as It is likely that ..., perhaps ..., actually ..., it is possible that..., and I think that ..., etc., speakers modify the meaning, or the illocutionary force, of the utterances they make. This feature, which has been called ‘modality’, is present, among others, in the genre of political interview and serves various functions. The present contribution offers an inquiry into the linguistic means that politicians utilize to modify their involvement in, or their detachment from, the proposition and in this way they alter the meaning of their statements.
This paper explores the ways in which young people aged 12 to 18 who were born in Central and Eastern European EU countries but now live in the United Kingdom construct their future imaginaries in the context of Brexit. It reports on findings from a large-scale survey, focus groups and family case studies to bring an original perspective on young migrants’ plans for the future, including mobility and citizenship plans, and concerns over how Britain’s decision to leave the European Union might impact them. While most of the young people planned to stay in Britain for the immediate future, it was clear that Brexit had triggered changes to their long-term plans. These concerns were linked to uncertainties over access to education and the labour market for EU nationals post-Brexit, the precarity of their legal status and their overall concerns over an increase in racism and xenophobia. While our young research participants expressed a strong sense of European identity, their imaginaries rarely featured ‘going back’ to their country of birth and instead included narratives of moving on to more attractive, often unfamiliar, destinations. The reasons and dynamics behind these plans are discussed by drawing on theories of transnational belonging.
The operational mineral deposit reconnaissance tends to evaluate its parameters to conduct safe and profitable production. Particular deposit parameters, important from the point of mineral deposit management, are estimated on the basis of observations carried out by mining geological surveys. These observations usually involve sampling, drilling, laboratory analyses and others. The use of fuzzy description to assess the parameters of the mineral deposit was proposed in the paper. In the fuzzy characteristics, an imprecise descriptive description appeared in place of a particular numerical quantity. This approach was used to description of the ore deposit features (metal content, volume, and metal yield) by assigning them specific characteristic functions, whose distributions were based on basic statistical quantities. Characteristic functions can be used to prepare operational strategies for any configuration of required deposit parameters resulting from the production management needs. For this purpose, selected logical operators of fuzzy sets were used. In the next approach to fuzzy modeling, an opportunity to characterize the deposit in a subjective approach was indicated, where the assessment of the deposit parameters is based on rough, in some way, discretionary observation and evaluation. Such model construction enabled the overall assessment of the deposit from the point of view of any parameters. Through the implementation of appropriate inference rules, adequate fuzzy control planes were obtained, which may also be useful in the context of operational mine strategy planning.
Szyby górnicze stanowią podstawowe znaczenie dla prawidłowego i bezpiecznego funkcjonowania kopalń podziemnych. W związku z tym ich obudowie stawia się wysokie wymagania, które okresowo weryfikowane są odpowiednimi badaniami oraz oceną jej stanu według obowiązujących norm i przepisów. Te z kolei obligują rzeczoznawców do stosowania coraz bardziej zaawansowanych metod pomiarowych, pozwalających w sposób precyzyjny określić rodzaj i wielkość uszkodzeń obudowy szybowej, co ma zasadniczy wpływ na ocenę jej stateczności. W artykule zostały przedstawione nowoczesne, a zarazem optymalne i kompleksowe metody badań obudowy szybów górniczych. Artykuł oprócz prezentacji metod badawczych, zawiera wiele wskazówek praktycznych, wpływających na poprawność wykonywanych badań, a tym samym na adekwatność wyników. W szczególności zostały omówione badania obudowy szybów metodami nieniszczącymi i niszczącymi, ocena makroskopowa obudowy oraz badania laboratoryjne próbek obudowy pobranych z obmurza szybu. Szczególną uwagę zwrócono również na nowoczesne badania deformacji obudowy, z wykorzystaniem skaningu laserowego w technologii 3D oraz metodę grawimetryczną, do określenia stanu górotworu za obudową szybu. Opisane metody badawcze stanowią podstawowy sposób sprawdzania stanu technicznego obudowy szybów górniczych, na podstawie których można stwierdzić, czy szyby mogą bezpiecznie funkcjonować, czy też ich obudowa wymaga naprawy. Prezentowane doświadczenia oparte są na wynikach badań wykonanych przez autora w wielu kopalniach węgla kamiennego podczas badań obudowy kilkudziesięciu szybów górniczych.
The paper presents a solution of the control system for fatigue test stand MZGS-100 PL, comprising the integrated Real-Time controller based on FPGA (Field-Programmable Gate Array) technology with LabVIEW software. The described control system performs functions such as continuous regulation of speed induction motor, measuring strain of the lever machine and the test specimen, displacement of the polyharmonic vibrator, as well as the elimination of interferences, overload protection and emergency stop of the machine. The fatigue test stand also allows to set the pseudo-random history of energy parameter W(t).
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