Nowe zasoby w kolekcji Artykuły http://suw.biblos.pk.edu.pl/ Biblioteka Politechniki Krakowskiej lipinska@biblos.pk.edu.pl 60 <![CDATA[Applicability of 1,6-diphenylquinolin-2-one derivatives as fluorescent sensors for monitoring the progress of photopolymerisation processes and as photosensitisers for bimolecular photoinitiating systems]]> Fri, 13 Dec 2019 14:23:01 +0100 Topa, Monika; Petko, Filip; Galek, Mariusz; Machowski, Kamil; Pilch, Maciej; Szymaszek, Patryk; Ortyl, Joanna
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Abstrakt: The applicability of new 1,6-diphenylquinolin-2-oneas derivatives as fluorescent molecular sensors for monitoring the progress of photopolymerisation processes by Fluorescence Probe Technique (FPT) has been tested. The progress of cationic, free-radical and thiol-ene photopolymerisation for commercially available monomers: triethylene glycol divinyl ether (TEGDVE), trimethylolpropane triacrylate (TMPTA) and trimethylpropane tris(3-mercaptopropropionate) (MERCAPTO) was monitored. It was found that new derivatives of 1,6-diphenylquinolin-2-one shifted their fluorescence spectra towards shorter wavelengths with the progress of polymerisation, which enabled monitoring the progress in terms of fluorescence intensity ratios as the progress indicator. Derivatives of 1,6-diphenylquinolin-2-one show sensitivity to changes in both polarity and viscosity in the surrounding microenvironment during photopolymerisation processes. Therefore, it was shown that they are good candidates to act as fluorescent sensors for monitoring the kinetics of very quick processes, such as photopolymerisation processes. Furthermore, the effect of the nature of substituents attached to the 1,6-diphenylquinolin-2-one ring on the characteristics of emission spectra was identified. Moreover, the sensitivity of fluorescent sensors was compared with commercially available model sensors, such as 7-diethylamino-4-methylcoumarin (Coumarin 1) and trans-2-(2′,5′-dimethoxyphenyl)ethenyl-2,3,4,5,6-pentafluorobenzene (25ST). Moreover, it was also proven that selected derivatives of 1,6-diphenylquinolin-2-one exhibit an accelerating effect on the progress of cationic photopolymerisation of vinyl monomers (TEGDVE). Thus, the new 1,6-diphenylquinolin-2-one derivatives can be successfully used both as molecular fluorescence sensors to monitor the progress of photopolymerisation processes and as diaryliodonium salt photosensitisers to initiate cationic photopolymerisation processes in a UV-A range of 365 nm.]]>
<![CDATA[Does the carbon fibre coating reinforcement have an influence on the bearing capacity of high-performance self-compacting fibre-reinforced concrete? ]]> Fri, 13 Dec 2019 14:13:10 +0100 Ostrowski, Krzysztof
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Abstrakt: This study investigated the impact of the location of a carbon fibre coated reinforcement ring (CFCRr) inside the structure of high-performance self-compacting fibre-reinforced concrete (HPSCFRC). Nowadays, cement matrix is considered as an alternative binder when reinforcing concrete structures with composite materials. Due to the plastic behavior of composite structures at relatively low temperatures when carbon fibres are reinforced with epoxy resin, the author attempted to locate carbon fibres inside a concrete structure. Thanks to this, the reinforcement will be less vulnerable to high temperatures (during a fire) and more compatible with concrete. The fibres act as a perimeter reinforcement that is compatible with the concrete mixture. The position of the CFCRr in the structure of concrete has an influence on the load capacity, stiffness and stress-strain behavior of concrete elements. The research was conducted on circular shape short concrete columns and tested under axial compression. The results demonstrated that by including CFCRr inside a concrete specimen, the maximum compressive strength decreases with an increase in the number of composite rings and a greater distance from the vertical axis of symmetry to the edge of the element. It has been proven in these studies that carbon fibres do not have good adhesive properties between CFCRr and a concrete mixture. As a result of this phenomenon, a shear surface is created, which leads to crack propagation along the CFCRr. Therefore, the presented idea of an internal CFCRr should not be used when designing new concrete structures.]]>
<![CDATA[Riparian ground beetles in gravel bed rivers: validation of Invertebrate Bankfull Assessment method]]> Fri, 13 Dec 2019 08:57:23 +0100 Skalski, Tomasz; Kędzior, Renata; Radecki-Pawlik, Artur
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Abstrakt: Bankfull Assessment Method (IBA method) applies riverine invertebrate community of ground beetles as a biotic indicator of bankfull variation in a dynamic river. IBA index is calculated as a proportion of small sized individuals (1–6 mm) to large size individuals (18–24 mm) of ground beetles in given sample site. The aim of the study was to validate the IBA bankfull discharge method with 135 carabid assemblages collected in gravel-bed rivers of various modifications of channel morphology in the Polish Carpathians. Constrained canonical correspondence analysis revealed that biotic factors such as IBA, plant cover and plant height described most of the variation of small and large sized species abundance. The IBA index variation confirmed earlier expectation of the mean IBA values. Mean value of the index for the lowest bench is about 5, for the middle bench about 2 and it never exceeds 1 for the highest bench. The bankfull calculated using morphometric methods (Wolmann) was located between the first and second bench on each river. Values of the IBA for the lowest bench depend significantly on channel incision whereas modifications of vegetation affect the values for all three benches. The study presents high value of IBA method in estimating bankfull discharge which is considered to be important supporting flow predicting morphological changes responsible for river channel shape with direct connection to living organisms occupying river banks as well as to river environmental quality. Proposed simple method could be important for local watershed managers for prediction of bank embankments level (e.g. maximum level of rip-rap or gabions) or for maximum level of low head hydraulic structures when they are necessary in terms of river engineering works but when they are still built as environmental friendly hydraulic structures.]]>
<![CDATA[Intensification of catalytic processes through the pellet structuring: steady-state properties of a bifunctional catalyst pellet applied to generic chemical reactions and the direct synthesis of DME]]> Thu, 12 Dec 2019 08:50:59 +0100 Bizon, Katarzyna; Skrzypek-Markiewicz, Krzysztof; Pędzich, Dominik; Reczek, Natalia
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Abstrakt: Structuring of different types of catalytic active centers at a single-pellet level appears to be a promising and powerful tool for integration and intensification of multistep solid-catalyzed chemical reactions. However, the enhancement in the product yield and selectivity strongly depends on the proper choice of the distribution of different catalysts within the pellet. To demonstrate potential benefits from properly designed catalyst pellet, numerical studies were conducted with the aid of the mathematical model of a single spherical bifunctional catalyst pellet. The analysis was performed both for a system of two generic chemical reactions and for a real process, i.e., direct synthesis of dimethyl ether (DME) from synthesis gas via methanol. Evaluation of the pellet performance was done for three arrangements of the catalytic active sites within the pellet, i.e., a uniform distribution of two types of catalytic active centers in the entire volume of the pellet, and two core–shell structures. It was demonstrated that, especially for the larger pellets typical for fixed-bed applications, the product yield might be significantly improved by selecting proper catalyst arrangements within the pellet.]]>
<![CDATA[Modification of polyurethane viscoelastic foams by functionalized polyhedral oligomeric silsesquioxanes (POSS)]]> Thu, 12 Dec 2019 08:43:21 +0100 Bukowczan, Artur; Hebda, Edyta; Michałowski, Sławomir; Pielichowski, Krzysztof
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Abstrakt: The aim of this paper is to present synthesis and characterization routes of hybrid polyurethane viscoelastic foams reinforced by - inorganic nanoaddities. Recently, much attention has been given to polymer nanocomposites made with POSS (Polyhedral Oligomeric Silsesquioxanes) - a family of siloxane material consisting of inorganic silicon-oxygen core and organic functional groups. Functionalization of POSS enables formation of chemical linkages with polymer matrix and increases compatibility between the organic and inorganic components. Our research focused on the modification of polyurethane materials by functionalized POSS. Octa(3-hydroxy-3-methylbutyldimethylsiloxy) POSS containing eight hydroxyl groups and 1,2- propanediolisobutyl POSS with 2 hydroxyl groups were chosen as additional co-reagents which were mixed by ultrasound homogenizer in polyol phase. POSS was added in amounts 5, 10 and 15% by weight of polyol, and reacted with diisocyanate (TDI) to obtain PU/POSS composite. The effects of incorporation of POSS on the mechanical properties of PU-based hybrid composites were presented. Moreover, the morphology of PU/POSS hybrids was investigated by means of wide-angle X ray diffraction (WAXD) and scanning electron microscopy (SEM) techniques.]]>
<![CDATA[Expert evaluation of traffic signs: conventional vs. alternative designs]]> Thu, 12 Dec 2019 08:38:29 +0100 Ben-Bassat, Tamar; Zakowska, Lidia
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Abstrakt: Traffic sign comprehension is significantly affected by their compliance with ergonomics design principles. Despite the UN Convention, designs vary among countries. The goal of this study was to establish theoretical and methodological bases for evaluating the design of conventional and alternative signs. Thirty-one conventional signs and 1-3 alternatives for each conventional sign were evaluated for their compliance with three ergonomics guidelines for sign design: physical and conceptual compatibility, familiarity, and standardization. Twenty-seven human factors and ergonomics experts from ten countries evaluated the signs relative to their compliance with the guidelines. Analysis of variance across alternatives revealed that for 19 of the 31 signs, an alternative design received a significantly higher rating in its ergonomics design than the conventional sign with the same meaning. We also found a very high correlation between the experts' ratings and comprehension from previous studies. In conclusion, many countries use signs for which better alternative designs exist, and therefore UN Convention signs should be re-examined, and ergonomics experts evaluation can serve as a good surrogate for road users' comprehension surveys. Practitioner Summary: This study presents theoretical and methodological bases for evaluating the design of UN Conventional and alternative traffic signs. Human factors and ergonomics experts evaluated 31 conventional and 68 alternative road signs, based on ergonomics principles for sign design. Results indicated the need to re-examine poorly designed UN Convention signs.]]>
<![CDATA[Linguistic data mining with complex networks: A stylometric-oriented approach]]> Thu, 12 Dec 2019 08:13:32 +0100 Stanisz, Tomasz; Kwapień, Jarosław; Drożdż, Stanisław
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Abstrakt: By representing a text by a set of words and their co-occurrences, one obtains a word-adjacency network being a reduced representation of a given language sample. In this paper, the possibility of using network representation to extract information about individual language styles of literary texts is studied. By determining selected quantitative characteristics of the networks and applying machine learning algorithms, it is possible to distinguish between texts of different authors. Within the studied set of texts, English and Polish, a properly rescaled weighted clustering coefficients and weighted degrees of only a few nodes in the word-adjacency networks are sufficient to obtain the authorship attribution accuracy over 90%. A correspondence between the text authorship and the word-adjacency network structure can therefore be found. The network representation allows to distinguish individual language styles by comparing the way the authors use particular words and punctuation marks. The presented approach can be viewed as a generalization of the authorship attribution methods based on simple lexical features. Additionally, other network parameters are studied, both local and global ones, for both the unweighted and weighted networks. Their potential to capture the writing style diversity is discussed; some differences between languages are observed.]]>
<![CDATA[Influence of modifiers on thermal and optical properties of TeO2–P2O5–ZnO–PbF2 glasses]]> Wed, 11 Dec 2019 12:10:56 +0100 Reben, Manuela; Burtan-Gwizdała, Bożena; Cisowski, Jan; Grelowska, Iwona; Yousef, El Sayed; Bukalska, Julita
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Abstrakt: A series of fluorotellurite glasses based on 70TeO2–5MxOy–10P2O5–10ZnO–5PbF2 in mol%, where MxOy = (WO3, Nb2O5) doped with 2400 ppm of Er2O3 have been prepared by the conventional melt quenching method. The influence of modifiers on thermal and optical properties of glasses has been analyzed. Thermal characteristics of glasses like the glass transition temperature Tg, the temperature for the crystallization onset Tx, the maximum crystallization temperature Tc, and the thermal stability parameter were determined by the DSC method. The ellipsometric data have provided Sellmeier-type dispersion relations of the refractive index of the investigated glasses. The optical parameters are used to calculate the molar refractivity, molar polarizability, oxide ion polarizability, molar cation polarizability, and a number of polarizable atoms per unit volume for every glass composition in order to interpret the refractive index of these glasses.]]>
<![CDATA[Spectroscopic properties of Er3+-doped fluorotellurite glasses modified by Nb2O5 and WO3]]> Wed, 11 Dec 2019 12:02:20 +0100 Burtan-Gwizdała, Bożena; Reben, Manuela; Cisowski, Jan; Yousef, El Sayed; Lisiecki, Radosław; Grelowska, Iwona
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Abstrakt: We have investigated the spectroscopic properties of Er3+-doped fluorotellurite glasses with the basic molar composition 75%TeO2–10%P2O5–10%ZnO–5%PbF2, modified by replacing 5% TeO2 by a metal oxide, namely WO3 or Nb2O5. The absorption edge of the glasses studied has been described within the Urbach approach, while the absorption and photoluminescence spectra have been analyzed in terms of the standard Judd–Ofelt theory, along with the photoluminescence decay of the 4I13/2 and 4S3/2 levels of the Er3+ ion. The absorption and emission spectra of the 4I15/2 ↔ 4I13/2 infrared transition have been analyzed within the McCumber theory to yield the peak emission cross-section and figure of merit for the amplifier gain. It appears that the fluorotellurite glass containing WO3 as a modifier is characterized by the largest figure of merit, indicating this matrix as a promising new host for doping with Er3+ ions.]]>
<![CDATA[Dom towarowy dzisiaj. Rola nowych technologii w kształtowaniu formy architektonicznej]]> Tue, 10 Dec 2019 12:11:09 +0100 Knez, Anna Katarzyna
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Abstrakt: Zmiany w dziedzinie ekonomii generują transformacje układu przestrzennego miasta. Wpływają również na kształt i charakter architektury. W przypadku handlu, rosnąca konkurencja decyduje o konieczności skutecznej reklamy oraz wyjątkowej trosce o klienta. Uwarunkowania te determinują sposób myślenia o architekturze domu towarowego. Obecnie budynek staje się wizytówką marki i narzędziem promocji. Na przykładzie domów handlowych zbudowanych w ubiegłym dziesięcioleciu w Tokio wskazano te rozwiązania konstrukcyjno-materiałowe, które umożliwiły zbudowanie unikalnej formy architektonicznej, szczególną kompozycję elewacji, jak również nietypowe kształtowanie wnętrz tych obiektów.]]>
<![CDATA[New versatile bimolecular photoinitating systems based on amino-m-terphenyl derivatives for cationic, free-radical and thiol-ene photopolymerization under low intensity UV-A and visible lights sources]]> Mon, 09 Dec 2019 12:32:51 +0100 Hola, Emilia; Pilch, Maciej; Galek, Mariusz; Ortyl, Joanna
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Abstrakt: The performance of a series of 2-amino-4,6-diphenyl-benzene-1,3-dicarbonitrile derivatives (i.e., amino-meta-terphenyls) as visible light sensitizers for diphenyliodonium salt for enabling photopolymerization at different irradiation wavelengths was studied. The structural modification of a 2-amino-4,6-diphenyl-benzene-1,3-dicarbonitrile compound was carried out. This modification, in the first step, involved a substitution of the amino group for the investigation of the effect of the amine type order on the sensitizing properties of these compounds in a bimolecular photoinitiating system composed of iodonium salt. Furthermore, to improve the spectroscopic properties, which is the scope and size of the extinction coefficient, an additional modification of the 2-amino-4,6-diphenyl-benzene-1,3-dicarbonitrile compound was proposed. The second step of modification consisted of the incorporation of an electron donating group of 4-thiomethylphenyl at the para position into the phenyl ring attachment at the 4-position of the amino-meta-terphenyl moiety. This approach allowed the study of structure/reactivity/efficiency relationships of the investigated meta-terphenyl derivatives as photosensitizers of iodonium salt for the cationic ring-opening photopolymerization of epoxides, free-radical photopolymerization of acrylates in thin films and also in a thick sample of methacrylate blend and additionally for the thiol–ene photopolymerization of allyl and thiol monomers upon UV-A and visible light exposure using Light Emitting Diodes (LEDs) with maximum emission at 365 nm, 405 nm, and 420 nm. Moreover, two different initiation mechanisms were also analysed for bimolecular photoinitiating systems based on 2-amino-4,6-diphenyl-benzene-1,3-dicarbonitrile derivatives with iodonium salt or amine e.g., ethyl 4-(dimethylamino)benzoate through steady-state photolysis experiments, fluorescence experiments, theoretical calculations of molecular orbitals, and electrochemical analysis. Our results showed that 2-amino-4,6-diphenyl-benzene-1,3-dicarbonitrile derivatives have extensive applications in different types of photopolymerization processes across the photo-oxidation or photo-reduction mechanism of their excited species promoted by soft UV-A and visible light. ]]>
<![CDATA[Wyznaczanie błędów średnich przy rozwiązywaniu problemów wyrównawczych]]> Mon, 09 Dec 2019 11:36:08 +0100 Kordylewska, Zofia; Kordylewski, Jerzy; Styrylska, Teresa
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<![CDATA[Situation of landscape architect profession in Europe based on the teamwork supporting the regulation of the profession professional recognition assistance (PRA) IFLA Europe]]> Sat, 07 Dec 2019 10:24:50 +0100 Forczek-Brataniec, Urszula
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Abstrakt: IFLA EU to organizacja zrzeszająca architektów krajobrazu Europy. Od 2000 roku jest częścią IFLA World, wcześniej federacja była niezależną instytucją i nosiła nazwę EFLA. Jednym z najważniejszych celów prac zarówno oddziału europejskiego IFLA, jak i dawnej EFLA jest wzmacnianie i propagowanie zawodu architekta krajobrazu. Od lat realizowane są projekty mające za zadanie rozpoznanie stanu i pozycji zawodu w krajach europejskich. Jednym z nich jest ukończony w tym roku projekt PQD (Professional Qualifications Directive) prowadzony przez prof. Fritza Auwecka. Efektem projektu jest m.in. zebranie danych dotyczących stanu regulacji zawodu. Kontynuacją tego działania jest projekt PRA (Professional Recognition Assistance) wspierający zrzeszone organizacje w regulacji zawodu na szczeblu krajowym. Zespół roboczy to: Tony Williams - prezydent IFLA EU, Hermann Georg Gunnlaugsson – wiceprezydent, prof. Fritz Auweck – kierownik projektu PQD, Urszula Forczek-Brataniec – sekretarz generalny IFLA EU. Uzyskane dotychczas dane pozwalają stwierdzić, że obecnie w siedmiu krajach Unii Europejskiej zawód jest uregulowany na podstawie systemu izbowego. W krajach skandynawskich obowiązuje system pozbawiony izb zawodowych, natomiast w pozostałych krajach regulacje dokonywane są na poziomie lokalnego prawa lub nie występują. Dodatkowo, prawa do wykonywania zawodu w krajach, gdzie jest on uregulowany, również różnią się od siebie. Zebrany materiał zakreśla szeroki wachlarz możliwości stabilizacji zawodu, na różnych szczeblach. Obrazuje sposób osadzenia prawnego zawodu i zakres możliwości jego wykonywania, a także pozwalają na nowo spojrzeć na sprawę regulacji zawodu w Polsce.]]>
<![CDATA[Twórcza droga do architektury i jej wpływ na jakość mieszkalnictwa]]> Sat, 07 Dec 2019 09:58:04 +0100 Twardowski, Grzegorz
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Abstrakt: Celem pracy jest odnajdywanie sensu architektury, pokazywanie roli i znaczenia kompozycji i formy w twórczej drodze ku architekturze w środowisku mieszkaniowym. Wybrano znaczące przykłady dzieł architektonicznych z końca XX wieku, pokazujące twórczą drogę, którą podążają artyści oderwani od historyzmu. Rozważania idą w kierunku odczytywania architektury, nade wszystko intencji twórcy jako przekazów myśli. Poszukiwanie podobieństw w dziełach wybitnych artystów, tworzących wielkie dzieła sztuki.]]>
<![CDATA[Rondo niezgody]]> Sat, 07 Dec 2019 09:54:39 +0100 Porębska, Anna
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<![CDATA[Elicitation with methyl jasmonate combined with cultivation in the Plantform™ temporary immersion bioreactor highly increases the accumulation of selected centellosides and phenolics in Centella asiatica (L.) Urban shoot culture]]> Fri, 06 Dec 2019 10:13:59 +0100 Skrzypczak-Pietraszek, Ewa; Urbańska, Aneta; Żmudzki, Paweł; Pietraszek, Jacek
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Abstrakt: Centella asiatica (L.) Urban is an important pharmacopoeial plant used not only in medicine but also in cosmetology. C. asiatica agitated shoot cultures were established to study the influence of ethephon, methyl jasmonate, L‐phenylalanine (Eth 50 µM, MeJa 50 µM, L‐Phe 2.4 g/L of medium, respectively; seven variants of the supplementation) on the accumulation of secondary metabolites: the main centellosides (asiaticoside and madecassoside) and selected phenolic acids, and flavonoids in the biomass. Microshoots were harvested two and six days after the supplementation. Secondary metabolites were analyzed in methanolic extracts by UPLC‐MS/MS (centellosides) and by HPLC‐DAD (phenolics). In comparison with the reference cultures, the concentrations of individual secondary metabolites increased as follows: centellosides up to 5.6‐fold (asiaticoside), phenolic acids up to 122‐fold (p‐coumaric acid) and flavonoids up to 22.4‐fold (kaempherol). The highest production increase of individual compounds was observed for different variants of supplementation. Variant C (50 µM MeJa), the most optimal for centellosides and flavonoid accumulation, was selected for the experiment with bioreactors. Bioreactor Plantform™, compared to RITA® system and agitated cultures, appeared to be the most advantageous for secondary metabolites production in C. asiatica shoot cultures. The phenolic acid, flavonoid, centelloside, and total secondary metabolite productivity in Plantform™ system is 1.8‐fold, 1.7‐fold, 2.8‐fold, 2.1‐fold, respectively, higher than in MeJa elicitated agitated cultures, and 4.3‐fold, 7.3‐fold, 12.2‐fold, 7.2‐fold, respectively, higher than in control agitated cultures.]]>
<![CDATA[Tribological properties of a rubber seal under operation with oil containing MoS2 nanoparticles]]> Fri, 06 Dec 2019 09:50:34 +0100 Szczypiński-Sala, Wojciech; Tomala, Agnieszka; Lubas, Janusz
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Abstrakt: The issues associated with sealing operation are of vital significance due to their function in mechanics. The most universal, simple, and cheap solution of seals are O-rings. They are most commonly used for all seals. The article evaluates the operation characteristics of an O-ring seals under operation with oils containing MoS2 nanoparticles. The measurements were made on the sealing node model in a hydraulic cylinder where the round cross section seal cooperated with the piston rod. The changes of the friction force during rod movement resulting from the friction between the seal and the rod were analysed. The investigations presented in this paper allow one to conclude that, for the assumed research conditions, the average values of the friction force during instroke are higher for PAO oil with MoS2 additive in comparison to pure PAO base oil. In addition, the boundary velocity of the rod above in which the decrease of friction force was observed is higher for pure PAO oil.]]>
<![CDATA[The relationship between static and kinetic friction for plant granular materials]]> Fri, 06 Dec 2019 08:53:13 +0100 Wójcik, Artur; Frączek, Jarosław; Niemczewska-Wójcik, Magdalena
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Abstrakt: The article shows a direct relationship between the maximum frictional force Fst (static friction) and the mean frictional force Fkin (kinetic friction). The tests were carried out for three plant granular materials (peas, maize, triticale). The modified Amontons-Coulomb model of friction was proposed for the Fst and Fkin description. The additional statistical analysis showed a strong linear correlation (R2 = 0.95) between the Fst and Fkin forces for all combinations of moisture levels (9, 12, 15, 18%) and loads (16, 27, 42, 50, 61 N). This makes it possible to simplify the measurement procedure, which in the case of kinetic friction is relatively difficult to implement.]]>
<![CDATA[On a multistage optimization problem (I)]]> Fri, 06 Dec 2019 07:48:21 +0100 Majcher, G.; Styrylska, T.
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<![CDATA[Wieloetapowe wyrównywanie spostrzeżeń bezpośrednich zawarunkowanych]]> Fri, 06 Dec 2019 07:47:26 +0100 Majcher, G.; Styrylska, T.
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Abstrakt: The authors present a recurrent procedure for obtaining the simultaneous minimum Euclidean norm solution of the set of n linear equations A(1)v=b(1),...,A(n)v=b(n) when the matrix A=(A′(1):...:A′(n))′ is of full row rank.]]>
<![CDATA[Dwuetapowe wyrównywanie spostrzeżeń bezpośrednich zawarunkowanych]]> Fri, 06 Dec 2019 07:45:01 +0100 Styrylska, Teresa
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<![CDATA[Die exergetische Analyse von Prozessen der feuchten Luft]]> Fri, 06 Dec 2019 07:44:08 +0100 Szargut, J.; Styrylska, T.
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<![CDATA[Fretting wear simulation in a clamped joint based on the example of a rail vehicle wheel set]]> Wed, 04 Dec 2019 13:16:55 +0100 Michnej, M.; Guzowski, S.
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Abstrakt: The authors of this paper made an attempt to explain fretting wear development in the wheel – axle connection in model studies simulating actual exploitation conditions. The tests consisted of two stages. In the first one it was of essential importance to check the actual state of the surface and surface layer of both the elements after having made press-fit joint and the influence on this state of some chosen factors, such as the forced in value and the surface roughness. The second stage included fatigue tests of the connection in the conditions of rotary bending as well as macro- and microscopic analysis of the registered damages in order to determine the processes initiating wear development. On the basis of the achieved results the authors formulated the mechanism of fretting wear development in a press-fit joint in which the most important element is the phenomenon of adhesion. It was found that in fretting wear development initiation in a press-fit joint, adhesion phenomenon plays a decisive role, forming and breaking adhesive connections. The remaining types of wear, such as plastic deformation, oxidation, micro-machining play a minor role, intensifying the damaged formed earlier as a result of breaking adhesive connections.]]>
<![CDATA[O idei czwartej rewolucji przemysłowej w aspekcie kadry pracowniczej i wyrazu estetyczno-wrażeniowego]]> Wed, 04 Dec 2019 11:50:37 +0100 Złowodzki, Maciej
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Abstrakt: Współczesny dobrobyt kraje wysoko rozwinięte zawdzięczają rozwojowi przemysłu. Od 18. stulecia trwa proces określany jako rewolucja przemysłowa. Obecnie wyróżniamy w niej cztery etapy, z których ostatni, koncepcyjnie zapoczątkowany już w 21. wieku, popularnie nazywany jest Przemysł 4.0. Jego idea polega na pełnej robotyzacji produkcji w atmosferze inteligentnych miast i budynków. Wiąże się to też z powrotem wytwórczości z krajów azjatyckich do krajów wysokich technik i technologii. Można się spodziewać znacznych zmian w obrazie struktury zatrudnienia oraz rozbudowy struktur badawczych i kształcenia kadr – zwłaszcza w dziedzinie nauk technicznych i informatyki. Kierunek rozwoju architektury nowych struktur jest niewiadomą, choć można domniemywać rozwój w stronę minimalizmu, abstrakcjonizmu i podkreślania aspektów ekologicznych.]]>
<![CDATA[Przestrzeń publiczna na poprzemysłowym obszarze]]> Wed, 04 Dec 2019 11:04:06 +0100 Zaborska-Jagiełło, Agnieszka
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Abstrakt: Artykuł porusza problem kształtowania przestrzeni publicznych na poprzemysłowych obszarach. Przedstawiono przykład gazowni w Amsterdamie (Westergasfabriek), która po długim procesie rewitalizacji stała się nowoczesną i tętniącą życiem przestrzenią publiczną, jedną z największych atrakcji w mieście.]]>
<![CDATA[Kształtowanie się przestrzeni publicznej w miejskim środowisku zamieszkania – Wiedeń]]> Wed, 04 Dec 2019 10:20:47 +0100 Włoch-Szymla, Agnieszka
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Abstrakt: Vienna is a special city which preserved balance between public spaces surrounded by historical and contemporary architecture. The example of Vienna housing policy is an interesting issue with reference to shaping a public space in an urban housing environment. The problems of housing are treated as public utility and are the priority policy in the strategies of planning the development of a city.]]>
<![CDATA[Liquid penetration depth and strength of concretes modified with polymer admixtures under the action of crude-oil products]]> Tue, 03 Dec 2019 10:45:32 +0100 Gruszczyński, Maciej; Lenart, Małgorzata
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Abstrakt: In the present article, the research results of concretes modified with a polymer dispersion of vinyl-benzene and acrylic (PC1) and with a styrene–butadiene dispersion (PC2) are discussed. Concretes were exposed to diesel, non-ethylated fuel, and the standard mixture of light liquids for 1000 h. Concretes modified with polymer dispersions, especially with the styrene–butadiene dispersion(PC2),indicatedasmallerdegreeofliquidpenetrationintothedepthofsamplescompared to the control concrete. The compressive strength for tested concretes, determined after 1000 h of storage in crude-oil products, in comparison to the strength of samples stored in de-mineralized water was significantly decreased, with the maximum differences equal to 12% for PC2 concrete.]]>
<![CDATA[Tron królowej lodu]]> Tue, 03 Dec 2019 10:38:30 +0100 Kozłowski, Tomasz
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<![CDATA[[Wstęp]]]> Tue, 03 Dec 2019 10:24:52 +0100 Kozłowski, Tomasz
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<![CDATA[W poszukiwaniu nowej jakości przestrzeni miasta – obszar centrum Dąbrowy Górniczej]]> Tue, 03 Dec 2019 09:02:37 +0100 Musiał, Robert
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Abstrakt: Możliwość realizacji nowej struktury miasta na terenach poprzemysłowych, jak i konieczność przekształceń struktur istniejących, pozwalają na kreację nowych przestrzeni publicznych. Procesom tym towarzyszy problem nadania lub przywrócenia im cech miejskich tworzących klimat przestrzeni miasta. W artykule omówiono zagadnienie rozwiązań planistycznych w oparciu o wartości przestrzenne zachowane w istniejącej strukturze miasta. Zwrócono uwagę na znaczenie regulacji planistycznych zawartych w planach miejscowych jako instrumentu chroniącego przestrzeń publiczną.]]>
<![CDATA[Formula for determining the construction workers productivity including environmental factors]]> Mon, 02 Dec 2019 13:54:10 +0100 Malara, Jarosław; Plebankiewicz, Edyta; Juszczyk, Michał
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Abstrakt: The aim of this study is to build a mathematical model of the productivity of construction workers. It does so by selecting 17 factors that influence the productivity of construction workers and categorising them into five groups. For the mathematical description of the factors, fuzzy logic was used. A formula for calculating the work productivity of construction workers is proposed. The novelty of the approach proposed by the authors is rooted in the consideration of various factors that have the potential to influence the productivity of construction workers. To present the way the formula operates, a single assessment of ceiling formwork was undertaken. The verification of a model confirmed its capability of analyzing, evaluating, and predicting the productivity of construction workers with satisfying accuracy.]]>
<![CDATA[Signatures of the crypto-currency market decoupling from the Forex]]> Mon, 02 Dec 2019 13:51:32 +0100 Drożdż, Stanisław; Minati, Ludovico; Oświęcimka, Paweł; Stanuszek, Marek; Wątorek, Marcin
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Abstrakt: Based on the high-frequency recordings from Kraken, a cryptocurrency exchange and professional trading platform that aims to bring Bitcoin and other cryptocurrencies into the mainstream, the multiscale cross-correlations involving the Bitcoin (BTC), Ethereum (ETH), Euro (EUR) and US dollar (USD) are studied over the period between 1 July 2016 and 31 December 2018. It is shown that the multiscaling characteristics of the exchange rate fluctuations related to the cryptocurrency market approach those of the Forex. This, in particular, applies to the BTC/ETH exchangerate,whoseHurstexponentbytheendof2018startedapproachingthevalueof0.5,whichis characteristic of the mature world markets. Furthermore, the BTC/ETH direct exchange rate has already developed multifractality, which manifests itself via broad singularity spectra. A particularly significant result is that the measures applied for detecting cross-correlations between the dynamics of the BTC/ETH and EUR/USD exchange rates do not show any noticeable relationships. This could be taken as an indication that the cryptocurrency market has begun decoupling itself from the Forex.]]>
<![CDATA[Role of polypropylene fibres in concrete spalling risk mitigation in fire and test methods of fibres effectiveness evaluation]]> Mon, 02 Dec 2019 08:02:43 +0100 Hager, Izabela; Mróz, Katarzyna
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Abstrakt: The explosive behaviour of concrete in fire is observed in rapidly heated concrete. The main factors controlling the occurrence of spalling are related to the material’s low porosity and high density as well as the limited ability to transport gases and liquids. Thus, for high-strength, ultrahigh-strength, and reactive powder concrete, the risk of spalling is much higher than for normal-strength concrete. The paper presents the discussion on the leading hypothesis concerning the occurrence of concrete spalling. Moreover, the methods for spalling prevention, such as polypropylene fibre application, which has been found to be an effective technological solution for preventing the occurrence of spalling, are presented. Various tests and testing protocols are used to screen concrete mixes propensity toward spalling and to evaluate the polypropylene fibres’ effectiveness in spalling risk mitigation. The most effective testing methods were selected and their advantages were presented in the paper. The review was based mainly on the authors’ experiences regarding high performance concrete, reactive powder concrete testing, and observations on the effect of polypropylene fibres on material behaviour at high temperature.]]>
<![CDATA[Analysis of the results obtained from the application of the two-stage method with calculations of some statically indeterminate trusses]]> Mon, 02 Dec 2019 07:58:31 +0100 Rębielak, Janusz
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Abstrakt: The paper presents results of calculations of forces in members of selected types of statically indeterminate trusses carried out by application of the two-stage method of computations of such structural systems. The method makes possible to do the simple and approximate calculations of the complex trusses in two stages, in each of which is calculated a statically determinate truss being an appropriate counterpart of the basic form of the statically indeterminate truss structure. Systems of the statically determinate trusses considered in the both stages are defined by cancelation of members, number of which is equal to the statically indeterminacy of the basic truss. In the paper are presented outcomes obtained in the two-stage method applied for two different shapes of trusses and carried out for various ways of removing of appropriate members from the basic trusses. The results are compared with outcomes gained due to application of suitable computer software for computation of the same types of trusses and for the same structural conditions. ]]>
<![CDATA[Applying computational geometry to designing an occlusal splint]]> Mon, 02 Dec 2019 07:54:58 +0100 Tomaka, Agnieszka Anna; Luchowski, Leszek; Pojda, Dariusz; Skabek, Krzysztof; Tarnawski, Michał
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Abstrakt: The occlusal splint is one of the methods of treatment of discrepancies between the centric relation and maximal intercuspation (CR/MI), and other temporomandibular joint (TMJ) disorders. It is also a method of reducing the effects of bruxism. Designing an occlusal splint for a given relation between the maxilla and the mandible involves: creating partial surfaces, integrating them, and producing the splint on a 3D printer. The paper presents and compares some techniques used to design splint surfaces under a required therapeutic maxilla-mandible relation. Our main effort consisted in understanding the orthodontist’s way of forming the splint and choosing – or creating – computational geometry tools to support his work.]]>