The energy industry is undergoing a major upheaval. In Germany, for example, the large nuclear and coal-fired power plants in the gigawatt scale are planned to be shut down in the forthcoming years. Electricity is to be generated in many small units in a decentralized, renewable and environmentally friendly manner. The large 1000 MW multistage axial steam turbines used to this date are no longer suitable for these tasks. For this reason, the authors examine turbine architectures that are known per se but have fallen into oblivion due to their inferior efficiency and upcoming electric drives about 100 year ago. However, these uncommon turbine concepts could be suitable for small to micro scale distributed power plants using thermodynamic cycles, which use for example geothermal wells or waste heat from industry to generate electricity close to the consumers. Thus, the paper describes and discusses the concept of a velocity-compounded single wheel re-entry cantilever turbine in comparison with other turbine concepts, especially other velocity-compounded turbines like the Curtis-type. Furthermore, the authors describe the design considerations, which led to a specific design of a 5 kW air turbine demonstrator, which was later manufactured and investigated. Finally, first numerical as well as experimental results are presented, compared and critically discussed with regards to the originally defined design approach.
The article discusses basic issues related to Polish anthroponomastic terms, their development and frequency, taking into account the variability of terminological units and the co-existence of native and foreign forms (usually Greek or Latin). It presents problems related to defining a term, determining its scope or (in particular cases) status, indicating preferred, permissible or non-recommended variant forms, selection (reduction) of sub-terms, the existence of doublets with a grammatical number, acceptance or rejection of new terms, etc. In the text, among others, the following sources were used: the dictionary “Osnoven sistem i terminologija na slovenskata onomastika” [“Basic system and terminology of Slavic onomastics”] (1983), an article by Mieczysław Karaś “W sprawie polskiej terminologii onomastycznej” [“On Polish onomastic terminology”] (1968), studies by Henryk Górnowicz (1988) and Ewa Jakus-Borkowa (1987), encyclopedia “Polskie nazwy własne” [“Polish proper names”] (1998), the compendium “Słowiańska onomastyka” [“Slavic onomastics”] (2002–2003) and selected articles published in the journal “Onomastica”. The second part of the article presents the history, scope and definitions of the term ethnonym // ethnic name (based on selected compendia, monographs and contributory studies), paying attention to the types of names it covers. In addition, a preliminary structure of an entry in the terminological dictionary has been outlined, including such elements as: the term, its definition, variability // equivalent term, origin // explanation, its English equivalent, examples // usage, context of use, and additional aspects.
The article presents the criteria taken into account in determining the alignment of regional roads, with particular reference to bypasses of towns located along regional roads. To determine the criteria for the evaluation of variants and their hierarchy, the surveys were conducted using the Delphi method in two rounds, with electronic surveys (the CAWI method). Based on survey studies, an entry list of criteria was set up as a proposal for determining the alignment of regional roads.
Influenced by the dynamic pressure of the front abutment pressure and the lateral abutment pressure, large deformation of surrounding rock occurs advancing working face in the entry heading adjacent to the active longwall mining face. Based on the cause analysis of entry large deformation, a new technology was put forward to solve the problem, and the designing method of drilling hole parameters for directional hydraulic fracturing was formed. Holes are drilled in the entry or in the high drainage entry to a certain rock layer over the adjacent working face, hydraulic cutting or slotting at the bottom of a borehole were also applied in advance to guide the hydraulic fractures extend in expected direction, through which the hard roof above the coal pillar can be cut off directionally. As a result, the stress concentration around the entry was transferred, and the entry was located in a destressing area. The field test at Majialiang coal mine indicates that the propagation length of cracks in single borehole is more than 15 m. After hydraulic fracturing, the large deformation range of the entry is reduced by 45 m, the average floor heave is reduced by 70%, and the average convergence of the entry’s two sides is reduced by 65%. Directional hydraulic fracturing has a better performance to control the large deformation of the dynamic pressure of the entry heading adjacent to the advancing coal face. Besides, it can improve the performance of the safety production.
The authors discuss the main premises of the project “The most popular surnames in Poland — past and present. E-dictionary” which has been in development since July 2014 in IJP PAN in Krakow. They also present its basic aims and functions, progress already made and they compare it with other dictionaries of surnames. The authors describe several aspects of the dictionary related to IT and computers but also those concerned with onomastics and lexicography. Additionally, they pay particular attention to the information contained in specific parts of each entry.
Entries in steeply pitching seams have a more complex stress environment than those in flat seams. This study targets techniques for maintaining the surrounding rock mass stability of entries in steep seams through a case study of a steep-seam entry at a mine in southern China. An in-depth study of the deformation and instability mechanisms of the entry is conducted, employing field measurement, physical simulation experiment, numerical simulation, and theoretical analysis. The study results show that the surrounding rock mass of the entry is characterised by asymmetrical stress distribution, deformation, and failure. Specifically, 1) the entry deformation is characterised by a pattern of floor heaving and roof subsidence; 2) broken rock zones in the two entry walls are larger than those in the roof and floor, and the broken rock zone in the seam-floor side wall is larger than that in the seam-roof side wall; 3) rock bolts in the middle-bottom part of the seam-floor side wall of the entry are prone to failure due to tensile stress; and 4) rock bolts in the seam-roof side wall experience relatively even load and relatively small tensile stress. Through analysis, disturbances were found to occur in both temporal and spatial dimensions. Specifically, in the initial mining stage, the asymmetrical rock structure and stress distribution cause entry deformation and instability; during multiple-seam multiple-panel mining operations, a wedge-shaped rock mass and a quasi-arc cut rock stratum formed in the mining space may cause subsidence in the seam-floor side wall of the entry and inter-stratum transpression, deformation, and instability of the entry roof and floor. The principles for controlling the stability of the surrounding rock mass of the entry are proposed. In addition, an improved asymmetrical coupled support structure design for the entry is proposed to demonstrate the effective control of entry deformation.