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Number of results: 16
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Abstract

An interesting fact in the intellectual history of the fin-de-siècle and first three decades of the 20th century is that the crisis of modernity was understood in categories of sex and gender. In spite of the differences dividing the German intellectual trend of cultural pessimism, the conservative revolution, and Fascist thinking, all these paradigms are linked by the characteristic conviction that ‘modernity’, being the consequence of the French Revolution, was ruled by the ‘feminine principle’. This principle was supposed to represent what is anti-military, anti-state, and anti-cultural at the same time. Variations on the theory of male bonding (Männerbund) were the intellectual reaction to that ‘feminine principle’. The intellectual patterns described here find their continuation in contemporary conservative thought.

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Authors and Affiliations

Nina Gładziuk
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Abstract

Based on data collected during an UCG pilot-scale experiment that took place during 2014 at Wieczorek mine, an active mine located in Upper Silesia (Poland), this research focuses on developing a dynamic fire risk prevention strategy addressing underground coal gasification processes (UCG) within active mines, preventing economic and physical losses derived from fires.

To achieve this goal, the forecasting performance of two different kinds of artificial neural network models (generalized regression and multi-layer feedforward) are studied, in order to forecast the syngas temperature at the georeactor outlet with one hour of anticipation, thus giving enough time to UCG operators to adjust the amount and characteristics of the gasifying agents if necessary.

The same model could be used to avoid undesired drops in the syngas temperature, as low temperature increases precipitation of contaminants reducing the inner diameter of the return pipeline. As a consequence the whole process of UGC might be stopped. Moreover, it could allow maintaining a high temperature that will lead to an increased efficiency, as UCG is a very exothermic process.

Results of this research were compared with the ones obtained by means of Multivariate Adaptative Regression Splines (MARS), a non-parametric regression technique able to model non-linearities that cannot be adequately modelled using other regression methods.

Syngas temperature forecast with one hour of anticipation at the georeactor outlet was achieved successfully, and conclusions clearly state that generalized regression neural networks (GRNN) achieve better forecasts than multi-layer feedforward networks (MLFN) and MARS models.

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Authors and Affiliations

Alicja Krzemień
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Abstract

A passive autocatalytic hydrogen recombiner (PAR) is a self-starting device, without operator action or external power input, installed in nuclear power plants to remove hydrogen from the containment building of a nuclear reactor. A new mechanistic model of PAR has been presented and validated by experimental data and results of Computational Fluid Dynamics (CFD) simulations. The model allows to quickly and accurately predict gas temperature and composition, catalyst temperature and hydrogen recombination rate. It is assumed in the model that an exothermic recombination reaction of hydrogen and oxygen proceeds at the catalyst surface only, while processes of heat and mass transport occur by assisted natural and forced convection in non-isothermal and laminar gas flow conditions in vertical channels between catalyst plates. The model accounts for heat radiation from a hot catalyst surface and has no adjustable parameters. It can be combined with an equation of chimney draft and become a useful engineering tool for selection and optimisation of catalytic recombiner geometry.

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Authors and Affiliations

Antoni Rożeń
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Abstract

This article discusses passages in the works of Greek and Roman writers, from Homer to the Church Fathers and Procopius, in which the seaside is a place of carefree play, those in which looking at the sea seems to have a good influence on the human mind, those in which walking on the shore is an opportunity for a philosophical dispute, and those in which pleasure is derived from being alone near the sea.

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Authors and Affiliations

Jan M. Kozłowski
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Abstract

The practice capacity of a railway junction depends, in addition to the effective operation’s conditions, by the potential risk factors related to the design plan of the railway station. With the aim of an approach based on the “fuzzy sets” it is possible to determine the numeric value of the practice capacity by the logic – qualitative relations between the features of the railway junction and the potential risk factors. This methodology permits to try out the absolute value of a suitable vector β, (less then the unit) for the utilization of the theoretic capacity in conditions of maximum reliability of the system related to the aspect of safety (technique “fail safe”).

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Authors and Affiliations

F. Corriere
D. Di Vincenzo
M. Guerrieri
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Abstract

The paper depicts the relations between historian person and history cognition, especially the influence of his mind inclinations to cognitive biases on narrative.
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Authors and Affiliations

Maciej Dymkowski
ORCID: ORCID
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Abstract

A concept of the vector space of imperceptible observation errors in linear Gauss-Markov models with uncorrelated observations, initially proposed in the earlier work of the author, is presented together with some improvements and new developments. The gross errors falling into that vector space pass absolutely undetected through all possible statistical tests set in the least squares estimation and unnoticeably distort the resulting values of one or more of the model parameters. The relationship is established between the concept of imperceptible gross errors and the concept, proposed by other authors, of the gross errors which can be detected but not identified due to specific properties of a network's structure. The theory is illustrated with a simple numerical example.
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Authors and Affiliations

Witold Prószyński
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Abstract

The instability characteristics of a dielectric fluid layer heated from below under the influence of a uniform vertical alternating current (AC) electric field is analyzed for different types of electric potential (constant electric potential/ electric current), velocity (rigid/free) and temperature boundary conditions (constant temperature/heat flux or a mixed condition at the upper boundary). The resulting eigenvalue problem is solved numerically using the shooting method for various boundary conditions and the solution is also found in a simple closed form when the perturbation heat flux is zero at the boundaries. The possibility of a more precise control of electrothermal convection (ETC) through various boundary conditions is emphasized. The effect of increasing AC electric Rayleigh number is to hasten while that of Biot number is to delay the onset of ETC. The system is more stable for rigid-rigid boundaries when compared to rigid-free and least stable for free-free boundaries. The change of electric potential boundary condition at the upper boundary from constant electric potential to constant electric current is found to instill more stability on the system. Besides, increase in the AC electric Rayleigh number and the Biot number is to reduce the size of convection cells.

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Authors and Affiliations

M. Ravisha
K.R. Raghunatha
A.L. Mamatha
I.S. Shivakumara
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Abstract

The emission of dust from coal fired furnaces introduces a lot of contamination into the environment, including dangerous metal compounds, which occur as trace elements in hard and brown coal. After the coal is burnt, they are contained in the grains of respirable dust, which creates health hazard. The results of investigations into the distribution of several trace elements in granular composition of ash emitted from CFB boilers used in coal-fired heat and power station are presented. The research material was taken by means of a cascade impactor, enabling a different granulometrie fraction to be separated from a stream of dust that penetrated the electrofilter. The CP-AES method (inductively coupled plasma atomic emission spectroscopy) was used to determine trace elements after prior mineralization of samples by microwave method. The Authors presented the results of measurements and analyses, determining the ranges of trace elements' occurrence in dust, characterizing the distribution in PM,, PM25 and PM10 granulometrie fractions and determining the emission factors.
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Authors and Affiliations

Jan Konieczyński
Katarzyna Stec
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Abstract

Filtering Respiratory Protective Devices (FRPD) is not typically evaluated for exposure to volatile compounds, even though they significantly affect their protective performance. Such compounds are released into the atmosphere by industrial processes and pose serious health risks in people inhaling them. The adsorbent materials currently used to prevent those risks include activated carbon (AC). Zeolites and mesoporous silica materials (MCM) are very popular among the sorption materials. Due to their physical and chemical properties, they are able to adsorb significant amounts of volatile compounds from air. The melt-blown technology was used to produce filtering nonwovens with modifiers. As a result, polymer nonwoven structures with modifiers in the form of AC, zeolite (NaP1 type), molecular sieves (SM, SM 4Å) and mesoporous silica materials (MCM-41) were produced. The use of ACs (AC1 from Zgoda and AC2 from Pleisch) and their mixtures with others modifiers allowed to obtain satisfactory sorption, protective and utility properties. The longest breakthrough time against cyclohexane (approx. 53 min) was afforded by a variant containing AC, against ammonia (approx. 12 min) for the variant with AC2 and a mixture of AC2 and MCM-41. In the case of acetone vapor satisfactory breakthrough times were found for the variants with AC2 and AC1+SM (~20–25 min.). The present work deals with scientific research to improve workers’ and society’s health and safety by pursuing a better working life, and creating a safe social environment.
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Bibliography

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Authors and Affiliations

Agnieszka Brochocka
1
Aleksandra Nowak
1
Rafał Panek
2
Paweł Kozikowski
1
Wojciech Franus
2

  1. Central Institute for Labour Protection-National Research Institute, Lodz, Poland
  2. Lublin University of Technology, Lublin, Poland
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Abstract

Local wind conditions can vary strongly depending on the landmark and vegetation, as well as on the skyline of the buildings in an urban surrounding. Weather, season and time of day influence the yield of electric power. In order to promote the use of small wind turbines as an alternative to photovoltaic power generation, design optimization for locationoptimized small wind turbines was carried out. In this work, we want to concentrate on vertical axis wind turbines. Experimental studies, as well as numerical simulations, have been conducted. On the one hand, bionically optimized core structures will be integrated and implemented in the hybrid material of the turbine blades. Several optimization attempts have been examined for single blades. Detailed simulative investigations with large eddy simulations improve the aerodynamic behaviour of the new rotor design. Finally, based on the results of the studies and investigations, a new rotor will be manufactured and tested experimentally in the wind tunnel. A comparison with the reference system from the first part of the paper shows the improvements and effectiveness of the measures and processes investigated.
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Bibliography

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Authors and Affiliations

Daniel Lehser-Pfeffermann
1
Alexander Hamman
1
Frank Ulrich Rückert
1

  1. University of Applied Sciences Saarbrücken (htw saar), Faculty of Economic Sciences, Campus Rotenbühl, Waldhausweg 14, 66123 Saarbrücken, Germany
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Abstract

The quantitative description of an airlift bioreactor, in which aerobic biodegradation limited by carbonaceous substrate and oxygen dissolved in a liquid takes place, is presented. This process is described by the double-substrate kinetics. Mathematical models based on the assumption of plug flow and dispersion flow of liquid through the riser and the downcomer in the reactor were proposed. Calculations were performed for two representative hydrodynamic regimes of reactor operation, i.e. with the presence of gas bubbles only within the riser and for complete gas circulation. The analysis aimed at how the choice of a mathematical model of the process would enable detecting the theoretical occurrence of oxygen deficiency in the airlift reactor. It was demonstrated that the simplification of numerical calculations by assuming the “plug flow” model instead of dispersion with high Péclet numbers posed a risk of improper evaluation of the presence of oxygen deficiency zones. Conclusions related to apparatusmodelling and process design were drawn on the basis of the results obtained. The paper is a continuation of an earlier publication (Grzywacz, 2012a) where an analysis of single-substrate models of the airlift reactor was presented.

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Authors and Affiliations

Robert Grzywacz
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Abstract

The main purpose of the paper is to identify and analyse a state of exploratory motivating factors in terms of lean management as the instrument of a policy of human resource management in the face of COVID-19 pandemic implemented in service companies. The main question is: if the motivation system used in the companies works out up against the unpredictable situation such as COVID-19 pandemic? The secondary purpose of the paper is to recognise relations and dependencies between these factors, and the question is: what factors have the strongest or the weakest relations with Lean Staff Management (LSM) tools? This research designed based on interview was conducted due to the lack of existing studies on the current status of motivating factors in terms of lean management tools in two service companies (case studies) in the light of COVID-19. The results show that factors influencing work efficiency in a dominating manner were, primarily, financial incentives (almost 21%), communications (around 21%), and workplace atmosphere (almost 18%). The paper investigates also the benefits and concerns of implementing LSM in service companies during the pandemic. This research might help the service organization’s management to identify the employees‘ problems to implement more effective lean services.
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Authors and Affiliations

Patrycja Żegleń
1
Aldona Kluczek
2
Daniela Matusikova
3

  1. University of Rzeszów, Poland
  2. Warsaw University of Technology, Poland
  3. University of Presov, Slovakia
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Abstract

The study investigates the axial load behaviour of concrete filled battened steel columns not covered by the design standards. A series of full scale tests on two I-sections connected together with intermediate batten plates and filled with concrete were carried out. The main parameters varied in the tests are length of the members and strength of the concrete filling. One bare steel member was also tested and results were compared with those filled with concrete. The tests results were illustrated by load-strain curves. The main objectives of these tests were twofold: first, to describe behaviour of new steel-concrete columns and second, to analyze the influence of slenderness on load-carrying capacity.

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Authors and Affiliations

M. Siennicki
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Abstract

Civil engineering is one of the many fields of occurrences of uncertain parameters. The present paper in an attempt to present and describe the most common methods used for inclusions of uncertain parameters . These methods can be applied in the area of civil engineering as well as for a larger domain. Definitions and short explanations of methods based on probability, interval analysis, fuzzy sets, and convex sets are presented. Selected advantages, disadvantages, and the most common fields of implementation are indicated.

An example of a cantilever beam presented in this paper shows the main differences between the methods. Results of the performed analysis indicate that the use of convex sets allows us to obtain an accuracy of results similar to stochastic models. At the same time, the computational speed characteristic for interval methods is maintained.

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Authors and Affiliations

J. Pełczyński

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