Nowe zasoby w kolekcji Artykuły http://suw.biblos.pk.edu.pl/ Biblioteka Politechniki Krakowskiej lipinska@biblos.pk.edu.pl 60 <![CDATA[The effect of surface treatment with isocyanate and aromatic carbodiimide of thermally expanded vermiculite used as a functional filler for polylactide-based composites]]> Fri, 22 Oct 2021 08:00:52 +0200 Barczewski, Mateusz; Mysiukiewicz, Olga; Hejna, Aleksander; Biskup, Radosław; Szulc, Joanna; Michałowski, Sławomir; Piasecki, Adam; Kloziński, Arkadiusz
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Abstrakt: In this work, thermally expanded vermiculite (TE-VMT) was surface modified and used as a filler for composites with a polylactide (PLA) matrix. Modification of vermiculite was realized by simultaneous ball milling with the presence of two PLA chain extenders, aromatic carbodiimide (KI), and 4,4’-methylenebis(phenyl isocyanate) (MDI). In addition to analyzing the particle size of the filler subjected to processing, the efficiency of mechanochemical modification was evaluated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The composites of PLA with three vermiculite types were prepared by melt mixing and subjected to mechanical, thermomechanical, thermal, and structural evaluation. The structure of composites containing a constant amount of the filler (20 wt%) was assessed using FTIR spectroscopy and SEM analysis supplemented by evaluating the final injection-molded samples’ physicochemical properties. Mechanical behavior of the composites was assessed by static tensile test and impact strength hardness measurements. Heat deflection temperature (HDT) test and dynamic thermomechanical analysis (DMTA) were applied to evaluate the influence of the filler addition and its functionalization on thermomechanical properties of PLA-based composites. Thermal properties were assessed by differential scanning calorimetry (DSC), pyrolysis combustion flow calorimetry (PCFC), and thermogravimetric analysis (TGA). The use of filler-reactive chain extenders (CE) made it possible to change the vermiculite structure and obtain an improvement in interfacial adhesion and more favorable filler dispersions in the matrix. This translated into an improvement in impact strength and an increase in thermo-mechanical stability and heat release capacity of composites containing modified vermiculites.]]>
<![CDATA[Impact of different epoxidation approaches of tall oil fatty acids on rigid polyurethane foam thermal insulation]]> Fri, 22 Oct 2021 07:58:08 +0200 Abolins, Arnis; Pomilovskis, Ralfs; Vanags, Edgars; Mierina, Inese; Michałowski, Slawomir; Fridrihsone, Anda; Kirpluks, Mikelis
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Abstrakt: A second-generation bio-based feedstock-tall oil fatty acids-was epoxidised via two pathways. Oxirane rings were introduced into the fatty acid carbon backbone using a heterogeneous epoxidation catalyst-ion exchange resin Amberlite IR-120 H or enzyme catalyst Candida antarctica lipase B under the trade name Novozym® 435. High functionality bio-polyols were synthesised from the obtained epoxidated tall oil fatty acids by oxirane ring-opening and subsequent esterification reactions with different polyfunctional alcohols: trimethylolpropane and triethanolamine. The synthesised epoxidised tall oil fatty acids (ETOFA) were studied by proton nuclear magnetic resonance. The chemical structure of obtained polyols was studied by Fourier-transform infrared spectroscopy and size exclusion chromatography. Average molecular weight and polydispersity of polyols were determined from size exclusion chromatography data. The obtained polyols were used to develop rigid polyurethane (PU) foam thermal insulation material with an approximate density of 40 kg/m3. Thermal conductivity, apparent density and compression strength of the rigid PU foams were determined. The rigid PU foams obtained from polyols synthesised using Novozym® 435 catalyst had superior properties in comparison to rigid PU foams obtained from polyols synthesised using Amberlite IR-120 H. The developed rigid PU foams had an excellent thermal conductivity of 21.2-25.9 mW/(m·K).]]>
<![CDATA[Optimal reduction in the number of test vectors for soft processor cores implemented in FPGA]]> Fri, 22 Oct 2021 07:55:28 +0200 Węgrzyn, Mariusz; Jamro, Ernest; Dąbrowska-Boruch, Agnieszka; Wiatr, Kazimierz
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Abstrakt: Testing FPGA-based soft processor cores requires a completely different methodology in comparison to standard processors. The stuck-at fault model is insufficient, as the logic is implemented by lookup tables (LUTs) in FPGA, and this SRAM-based LUT memory is vulnerable to single-event upset (SEU) mainly caused by cosmic radiations. Consequently, in this paper, we used combined SEU-induced and stuck-at fault models to simulate every possible fault. The test program written in an assembler was based on the bijective property. Furthermore, the fault detection matrix was determined, and this matrix describes the detectability of every fault by every test vector. The major novelty of this paper is the optimal reduction in the number of required test vectors in such a way that fault coverage is not reduced. Furthermore, this paper also studied the optimal selection of test vectors when only 95% maximal fault coverage is acceptable; in such a case, only three test vectors are required. Further, local and global test vector selection is also described.]]>
<![CDATA[Maintenance strategies, periodic renovations and building modernisation in the aspect of the criterion of the whole life costs]]> Fri, 22 Oct 2021 07:52:36 +0200 Przesmycka, Apolonia; Wieczorek, Damian
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Abstrakt: The article deals with the issues of building exploitation and maintenance and focuses on the characteristics of the maintenance strategies mentioned in the ISO 15686-5:2017 Buildings and constructed assets - Service life planning - Part 5: Life-cycle costing. The article describes all three strategies recommended by the ISO standard (preventive, corrective and deferred maintenance). The purpose of the article is to conduct whole life costs analysis of three variants of modernisations, renovations and maintenance strategies for a selected building. The methods of economic efficiency assessment were used, such as net present value (NPV) method and internal rate of return (IRR) method.]]>
<![CDATA[A novel fast feedforward neural networks training algorithm]]> Thu, 21 Oct 2021 13:36:24 +0200 Bilski, Jerzy; Kowalczyk, Bartosz; Marjański, Andrzej; Gandor, Michał; Zurada, Jacek
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Abstrakt: In this paper a new neural networks training algorithm is presented. The algorithm originates from the Recursive Least Squares (RLS) method commonly used in adaptive filtering. It uses the QR decomposition in conjunction with the Givens rotations for solving a normal equation - resulting from minimization of the loss function. An important parameter in neural networks is training time. Many commonly used algorithms require a big number of iterations in order to achieve a satisfactory outcome while other algorithms are effective only for small neural networks. The proposed solution is characterized by a very short convergence time compared to the well-known backpropagation method and its variants. The paper contains a complete mathematical derivation of the proposed algorithm. There are presented extensive simulation results using various benchmarks including function approximation, classification, encoder, and parity problems. Obtained results show the advantages of the featured algorithm which outperforms commonly used recent state-of-the-art neural networks training algorithms, including the Adam optimizer and the Nesterov’s accelerated gradient.]]>
<![CDATA[Multiple steady states in the photocatalytic reactor for colored compounds degradation]]> Thu, 21 Oct 2021 13:31:00 +0200 Szyman, Jakub
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Abstrakt: The paper reports the occurrence of multiple steady-state zones in most of the constructions of fixed-bed photocatalytic reactors. Such a phenomenon has not been ever observed in a field of photocatalytic reactors. The simulation has been provided for a common case in a photocatalysis—the degradation of colored compounds. The mathematical model of the photocatalytic reactor with immobilized bed has been stated by a simple ideal mixing model (analogous to the CSTR model). The solution has been continued by the two parameters—the Damköhler number and the absorption coefficient related to the inlet stream concentration. Some branches of steady states include the limit point. The performed two-parametric continuation of the limit point showed the cusp bifurcation point. Besides the numerical simulation, the physical explanation of the observed phenomenon has been provided; the multiple steady-states occurrence is controlled by light absorption–reaction rate junction. When the reaction rate is limited by the light absorption, we can say that a light barrier occurs. The dynamical simulations show that when the process is operated in a field of multiple steady states, the overall reactor efficiency is related to the reactor set-up mode.]]>
<![CDATA[Triangular functionally graded porous moderately thick plates-deformations and free vibrations]]> Wed, 20 Oct 2021 14:02:21 +0200 Muc, Aleksander
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Abstrakt: Since the finite element analysis of deformations for plates made of functionally graded materials cannot be carried out with the use of commercial FE packages, aconsistent method of analytical analysis is proposed in the paper. The method of the analysis is based on the application of the weighted residuals and the Bubnov–Galerkin method. The 2D formulation of moderately thick plates is adopted herein for classical and transverse shear deformation plate models (first and third order). Plate deformations subjected to uniform normal pressure and free vibrations are considered. The validity of the analytical model was verified by the comparison of results with FE analysis for isotropic plates. Two correction multipliers were proposed in order to take into account the unsymmetric composition of functionally graded porous plate walls.]]>
<![CDATA[Performance analysis of rough set–based hybrid classification systems in the case of missing values]]> Wed, 20 Oct 2021 12:19:52 +0200 Nowicki, Robert K.; Seliga, Robert; Żelasko, Dariusz; Hayashi, Yoichi
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Abstrakt: The paper presents a performance analysis of a selected few rough set–based classification systems. They are hybrid solutions designed to process information with missing values. Rough set-–based classification systems combine various classification methods, such as support vector machines, k–nearest neighbour, fuzzy systems, and neural networks with the rough set theory. When all input values take the form of real numbers, and they are available, the structure of the classifier returns to a non–rough set version. The performance of the four systems has been analysed based on the classification results obtained for benchmark databases downloaded from the machine learning repository of the University of California at Irvine.]]>
<![CDATA[A novel grid-based clustering algorithm]]> Wed, 20 Oct 2021 12:17:22 +0200 Starczewski, Artur; Scherer, Magdalena M.; Książek, Wojciech; Dębski, Maciej; Wang, Lipo
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Abstrakt: Data clustering is an important method used to discover naturally occurring structures in datasets. One of the most popular approaches is the grid-based concept of clustering algorithms. This kind of method is characterized by a fast processing time and it can also discover clusters of arbitrary shapes in datasets. These properties allow these methods to be used in many different applications. Researchers have created many versions of the clustering method using the grid-based approach. However, the key issue is the right choice of the number of grid cells. This paper proposes a novel grid-based algorithm which uses a method for an automatic determining of the number of grid cells. This method is based on the kdist function which computes the distance between each element of a dataset and its kth nearest neighbor. Experimental results have been obtained for several different datasets and they confirm a very good performance of the newly proposed method.]]>
<![CDATA[Influence of structural schemes on the shaping of historical wooden buildings: on the examples of traditional Chinese pavilions, pavilions of the Chinoiserie style and Ukrainian wooden churches]]> Wed, 20 Oct 2021 12:13:46 +0200 Ivashko, Yulia; Chang, Peng; Dmytrenko, Andrii; Kozłowski, Tomasz; Mykhailovskyi, Denys
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Abstrakt: In this paper, without denying the influence of the function on design, the influence of traditional constructive schemes on design is presented on the examples of Chinese pavilions and Ukrainian wooden churches. It is demonstrated how structural systems directly determined massing design: for example, the traditional Chinese dougong construction determined the original shape of curved Chinese roofs, and how the use of log construction in Ukrainian wooden churches-without crossbars or with crossbars-with load redistribution slightly inclined to the central axis, determined tower compositions with a combination of individual masses open to the zenith of the dome in the interior. It is shown how, in the case of a simplified copying of only the external form, without conforming to the form in the structural scheme, the form turns into a decoration, as in the European Chinoiserie style.]]>
<![CDATA[A short history of the form of octagonal and elliptical city squares]]> Wed, 20 Oct 2021 12:10:24 +0200 Motak, Maciej; Woźniczka, Magdalena
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Abstrakt: The article starts with the short discussion of two geometrical figures, i.e., octagon and ellipse, their genesis in architecture and urban design, and the examples of buildings whose plans were based upon them. Then, the selected octagonal and elliptical city squares are discussed: their genesis, context, layout, architecture surrounding the square, objects appearing in the square and, most specially, urban form and composition. The theory of architectural-landscape interiors has been applied to pinpoint the type of city squares by the assessing of the degree of openings in the square’s perimeter. The review consists of 22 case studies (9 octagonal and 13 elliptical) from the 15ᵗʰ to the 20ᵗʰ century. The last discussed case in each group, both atypical created in Krakow in the 20ᵗʰ century, are discussed even more thoroughly. The conclusions were presented first separately for octagonal and elliptical city squares and finally also for both groups in a comparative way.]]>
<![CDATA[Effect of reclaimed asphalt shingles addition on asphalt concrete dynamic modulus master curves]]> Tue, 19 Oct 2021 12:08:22 +0200 Zieliński, P.
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Abstrakt: The paper presents the comparison of dynamic modulus and phase lag in different loading conditions for asphalt concrete mixture with or without reclaimed asphalt shingles (RAS) addition. For each mixture, 6 samples were tested using the four point bending beam method, at four temperatures and at six frequencies. The results of the study were subjected to the analysis of the statistical significance of differences between mixtures. The graphic form of results presentation includes Black curves and Cole-Cole plots. Then, matching the sigmoidal functions enabled the creation of master curves of the complex stiffness module and the phase shift angle, being a function of the load frequency. It has been observed that the mixture with the addition of RAS has higher stiffness and elasticity in the range of higher temperatures (20°C and 30°C) and lower load frequencies, which results in higher values of the complex stiffness module and lower values of the phase lag. At 0°C, the behavior of both mixtures is very similar, while at 10°C significant differences between the tested mixtures were found only for low frequency loads (up to 5 Hz). Test results have shown that mixtures with the addition of RAS have a lower thermal sensitivity in terms of the complex stiffness modulus and phase lag than the reference mixture. The above results confirmed an improvement in rutting resistance for RAS mixes observed in previous work.]]>
<![CDATA[Switching arc energy limitation approach for LV circuit breakers]]> Tue, 19 Oct 2021 11:38:24 +0200 Smugala, Dariusz; Bonk, Michal
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Abstrakt: This paper presents an experimentally verified approach to deriving switching arc energy limitations for low-voltage (LV) circuit breakers (CBs). Air-insulated contactors equipped with additional vacuum-insulated (VI) arcing contacts were tested for AC and DC current interruption efficiency, respectively. In the study, the contact arrangements of reed relay VI contact switches of low current breaking capacity combined with air-insulated contactors were examined. Tests were performed on selected LV CBs inductively loaded for LV power network rated voltages. A comparative analysis of the arc energy resulting from various arc time durations recorded during the switching-off operation was performed. Using a variety of either basic CB air-insulated contact systems or combined contact systems, a practical assessment of the proposed idea for enhancing the arc quenching efficiency was undertaken. As a result of the implementation of the proposed idea, the arc burning duration time was indicated as being hundreds of times shorter. In most cases, a complete arc reduction was achieved. Moreover, the resulting arc energy dissipation during the breaking operation was substantially minimized. Consequently, a significant increase in the total current breaking capacity of the tested CBs was achieved.]]>
<![CDATA[Biologiczne tusze do drukowania 3D narządów i tkanek]]> Tue, 19 Oct 2021 10:56:59 +0200 Głąb, Magdalena; Słota, Dagmara
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Abstrakt: Biodrukowanie 3D jest technologią wykazującą duży potencjał w medycynie regeneracyjnej. Technologia umożliwia wytworzenie trójwymiarowych funkcjonalnych tkanek i sztucznych narządów w oparciu o odpowiednie tusze biologiczne. Przegląd dostarcza informacji o biotuszach stosowanych w technologii biodruku 3D. W najnowszych doniesieniach literaturowych uwzględniano podział biotuszy ze względu na ich zastosowanie w wytwarzaniu konkretnych tkanek i narządów. Główną uwagę zwrócono na biotusze przeznaczone do regeneracji tkanki chrzęstnej, kostnej oraz nerwowej. Ponadto zaprezentowano także najnowsze badania prowadzone w kierunku opracowania biotuszy stosowanych w odbudowie skóry, naczyń krwionośnych, a także wątroby.]]>
<![CDATA[Transient CFD simulation of charging hot water tank]]> Tue, 19 Oct 2021 09:27:15 +0200 Dzierwa, Piotr; Taler, Jan; Peret, Patryk; Taler, Dawid; Trojan, Marcin
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Abstrakt: This paper presents characteristics of heat accumulation system operation in one of the Polish combined heat and power (CHP) plants. The heat source cooperating with this installation is cogeneration units consisting of gas engines with a total heat output of 8 MWt and total electrical power of 8 MWe. The total thermal capacity of the non-pressure hot water accumulator is 75 MWh. An important issue in the case of hot water tanks is thermal stratification caused by the difference in density between higher-temperature water, located at the top of the hot water storage tank and colder water at its bottom. The article presents the results of numerical analysis based on the axial-symmetric model of a hot water tank using Ansys Fluent R19.2 software. Simulations with the Computational Fluid Dynamics (CFD) method were carried out for the process of charging the heat accumulator lasting 10 h. The effect of mesh density on the obtained results was analysed. The results were compared with the measurement data from the CHP plant. Heat losses from the hot water tank were compared with the measurement data from the CHP plant. Heat losses from the hot water tank were taken into account and the density characteristics of the heat flux lost to the environment were presented.]]>
<![CDATA[On the question of stepwise [4+2] cycloaddition reactions and their stereochemical aspects]]> Tue, 19 Oct 2021 09:18:34 +0200 Jasiński, Radomir
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Abstrakt: Even at the end of the twentieth century, the view of the one-step [4+2] cycloaddition (Diels-Alder) reaction mechanism was widely accepted as the only possible one, regardless of the nature of the reaction components. Much has changed in the way these reactions are perceived since then. In particular, multi-step mechanisms with zwitterionic or diradical intermediates have been proposed for a number of processes. This review provided a critical analysis of such cases.]]>
<![CDATA[Near-to-zero switching synchronization approach for DC electromagnet actuated relays]]> Thu, 14 Oct 2021 14:35:46 +0200 Smugala, D.; Gebczyk, J.; Wawro, M.; Czuchra, W.
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Abstrakt: This paper puts forward an idea for DC electromagnetically (EM) actuated switching devices operation improvement by means of an electronic controller application. The idea is aimed at applying compensation for the movable armature inertia and the time required for coil (de)energization. Based on the results of the measurements of the tested contactors switching parameters, the most efficient (de)energizing conditions for neartozero synchronized switching (NZSS) method application were determined. The NZSS process realization approach operates on the principle of controlling the driving coil supply voltage delivery moment. By means of the same controller circuit, voltage-zero-synchronized (VZS) contacts making and current-zero-synchronized (CZS) contacts breaking operations were realized. The method was experimentally verified for various supply conditions and load parameters. Long-term tests confirm the suitability of the method for low-voltage (LV) EM actuated switching devices. The circuit was able to control various EM drives with no modification required for the structure in which it was used.]]>
<![CDATA[Właściwości mechaniczne i użytkowe rur stalowych w gatunku C/6/X52]]> Thu, 14 Oct 2021 14:32:36 +0200 Jonderko, Henryk; Psonka, Wojciech; Stankiewicz, Marek
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<![CDATA[Właściwości mechaniczne i użytkowe rur stalowych w gatunku C/6/X52]]> Thu, 14 Oct 2021 14:12:54 +0200 Jonderko, Henryk; Psonka, Wojciech; Stankiewicz, Marek
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<![CDATA[Podstawowe własności mechaniczne stali S.A. 387 Grade 22 Class 2 w zakresie temperatury eksploatacji]]> Thu, 14 Oct 2021 14:10:53 +0200 Stankiewicz, Marek; Baran, Marek; Stępień, Tadeusz
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<![CDATA[Weryfikacja młotów udarnościowych w świetle wymagań normy ASTM E23 i procedury NIST]]> Thu, 14 Oct 2021 14:09:06 +0200 Stankiewicz, Marek; Cęckiewicz, Stanisław
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<![CDATA[Właściwości mechaniczne blach stalowych w zbiornikach paliwowych narażonych na długotrwałe oddziaływanie korozji atmosferycznej]]> Thu, 14 Oct 2021 14:06:53 +0200 Siudut, Janusz; Stankiewicz, Marek
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<![CDATA[Ocena wiarygodności badań twardości złączy spawanych przenośnymi twardościomierzami MICRODUR]]> Thu, 14 Oct 2021 14:04:42 +0200 Stankiewicz, Marek; Psonka, Wojciech; Faligowski, Andrzej
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<![CDATA[Tradycja na nowo odkryta]]> Thu, 14 Oct 2021 14:02:21 +0200 Olesiak, Justyna
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Abstrakt: Artykuł we wstępie przybliża aspekty programowe, funkcjonalne i estetyczne tradycyjnego budownictwa łemkowskiego w regionie Sądecczyzny. Podjęto próbę syntezy i na jej podstawie sformułowania wytycznych projektowych dla obiektów współczesnych. Jak się okazuje, wiele prawideł, według których kształtowano tradycyjne budynki, znajduje odzwierciedlenie w wymogach architektury energooszczędnej i przyjaznej środowisku. Przedstawiona w artykule propozycja projektowa - dom energooszczędny w Królowej Górnej - wpisuje się w nurt architektury wernakularnej i zorientowanej na zrównoważony rozwój.]]>
<![CDATA[Spawanie rur w gatunku Gr. C/6/X52 drutem proszkowym]]> Thu, 14 Oct 2021 13:13:34 +0200 Stankiewicz, Marek; Jonderko, Henryk; Kijowski, Dariusz; Psonka, Wojciech
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Abstrakt: W publikacji przedstawiono własności mechaniczne i użytkowe rur w potrójnym gatunku Gr. C/6/X52 wg ASTM i API 5L oraz zaproponowano technologię spawania FCAW z użyciem drutu rdzeniowego OK Tubrod 15.11 gwarantującą uzyskanie wymaganych własności mechanicznych, w tym wysokiej udarności KCV w temperaturze -50°C.]]>
<![CDATA[Porównanie różnych metod wyznaczania granicy plastyczności w statycznej próbie rozciągania metali i stopów]]> Thu, 14 Oct 2021 13:08:23 +0200 Stankiewicz, Marek; Psonka, Wojciech
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<![CDATA[Granice akceptowalności wyników kontroli jakości żaroodpornych wymurówek pieców grzewczych]]> Thu, 14 Oct 2021 13:05:46 +0200 Stankiewicz, Marek; Rybak, Marek
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<![CDATA[Review of solutions for the use of phase change materials in geopolymers]]> Thu, 14 Oct 2021 10:06:55 +0200 Łach, Michał; Pławecka, Kinga; Bąk, Agnieszka; Adamczyk, Marcin; Bazan, Patrycja; Kozub, Barbara; Korniejenko, Kinga; Lin, Wei-Ting
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Abstrakt: The paper deals with the possibility of using Phase Change Materials (PCM) in concretes and geopolymer composites. The article presents the most important properties of PCM materials, their types, and their characteristics. A review of the latest research results related to their use in geopolymer materials is presented. The benefits of using PCM in building materials include the improvement of thermal comfort inside the building, and also the fact that the additive in the form of PCM reduces thermal gradients and unifies the temperature inside the concrete mix, which can reduce the risk of cracking. The paper also presents a critical analysis related to the feasibility of mass scale implementations of such composites. It was found that the use of PCM in sustainable construction is necessary and inevitable, and will bring a number of benefits, but it still requires large financial resources and time for more comprehensive research. Despite the fact that PCM materials have been known for many years, it is necessary to refine their form to very stable phases that can be used in general construction as well as to develop them in a cost-effective form. The selection of these materials should also be based on the knowledge of the matrix material.]]>
<![CDATA[Investigation on green synthesis, biocompatibility, and antibacterial activity of silver nanoparticles prepared using Cistus incanus]]> Thu, 14 Oct 2021 08:48:36 +0200 Florkiewicz, Wioletta; Pluta, Klaudia; Malina, Dagmara; Rudnicka, Karolina; Żywicka, Anna; Duarte Guigou, Martin; Tyliszczak, Bożena; Sobczak-Kupiec, Agnieszka
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Abstrakt: This paper describes the plant-mediated preparation of silver nanoparticles with aqueous extract and infusion of Cistus incanus leaves. To evaluate aqueous extract and infusion antioxidant capacity and total phenolic content the DPPH and Folin–Ciocalteau methods were utilized. The antioxidant capacity and total phenolic content of extract and infusion were equal to 85.97 ± 6.54 mg gallic acid equivalents per gram of dry weight.; 10.76 ± 0.59 mg/mL and 12.65 ± 1.04 mg gallic acid equivalents per gram of dry weight.; 3.10 ± 0.14 mg/mL, respectively. The formed nanoparticles displayed the characteristic absorption band in the 380–450 nm wavelength range. The average size of particles was in the 68.8–71.2 nm range. Morphology and phase composition analysis revealed the formation of spherical nanoparticles with a face-centred cubic structure. Immune compatibility tests of nanoparticles and plant extracts showed no activation of the THP1-XBlue™ monocyte. Cytotoxicity tests performed with L929 mice fibroblasts showed that nanoparticles should be utilized at a concentration of 16 ppm. The minimum inhibitory concentrations determined with the microdilution method for nanoparticles prepared with plant infusion for S. aureus and S. epidermidis were 2 ppm and 16 ppm, respectively.]]>
<![CDATA[Values of the historical parks and gardens of psychiatric hospitals in Kulparków and Kobierzyn as the basis for their revalorization]]> Thu, 14 Oct 2021 08:44:42 +0200 Staniewska, Anna; Petryshyn, Halyna; Lukashchuk, Halyna; Kliusa, Tetiana; Koprynia, Karolina
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Abstrakt: This paper discusses the revalorization of a historical park landscape with therapeutic features of psychiatric hospitals from the second half of the nineteenth and at the beginning of the twentieth century. It presents the history and architectural and landscape values of historical complexes of psychiatric hospitals in Kulparków near Lviv and in Kobierzyn near Cracow. The main features of these park and garden compositions are presented based on historic data and archival sources, the literature, surveys and field research. Despite the passage of time, the preservation of the original park compositions allows one to highlight their primary features and supplement them with harmoniously chosen contemporary elements. As a proposal of contemporary actions, revalorization concepts prepared in recent years developed as part of Master’s thesis projects were presented.]]>
<![CDATA[Formulation and evaluation of organo-mineral fertilizers based on sewage sludge optimized for maize and sunflower crops]]> Thu, 14 Oct 2021 08:41:52 +0200 Kominko, Halyna; Gorazda, Katarzyna; Wzorek, Zbigniew
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Abstrakt: The depletion of natural resources, energy consumption and environmental issues relating to fertilizer production processes are driving a move towards a more sustainable use of resources and the recycling of nutrients. With regard to the fertilizer industry, this gives the opportunity to use the fertilizing potential of alternative raw materials. This paper evaluates the possibility of using dried sewage sludge in the manufacture of organo-mineral fertilizers. Fertilizers based on sewage sludge with an addition of poultry litter ash and mineral fertilizers were developed and characterized in the study. It was possible to produce multicomponent organo-mineral fertilizers with optimized compositions for maize and sunflower crops, characterized by total nutrient content over 20%. Moreover, they contained beneficial secondary nutrients and micronutrients originated from waste materials. The fertilizers were free of pathogens and fulfilled the requirements related to heavy metal content according to Polish legislation. The method of manufacturing organo-mineral fertilizers based on waste materials is a simple waste management solution offering organic matter and nutrient recycling in line with the circular economy and reducing reliance on imported raw materials.]]>
<![CDATA[Evaluating the environmental impact of using cargo bikes in cities: a comprehensive review of existing approaches]]> Thu, 14 Oct 2021 08:39:20 +0200 Vasiutina, Hanna; Szarata, Andrzej; Rybicki, Stanisław
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Abstrakt: The impact of the use of cargo bicycles for delivery processes on the environment is undeniably positive: it leads to the reduction of pollutants, noise, and vibrations caused by traditional vehicles; decreases traffic jams; causes more effective use of public space; and others. But how should such an effect be measured? What tools should be used to justify the necessity for change to more sustainable means of transport? How can we improve the state of the environment considering the interests of logistics service providers? There is a large amount of scientific literature dedicated to this problem: by using different modeling approaches, authors attempt to address the issue of sustainable transport. This paper conducts a literature review in the field of green cargo deliveries, investigates the benefits and drawbacks of integrating cargo bikes in urban logistics schemes, and examines methodologies and techniques for evaluating the impact of using cargo bicycles on the environment. By providing an opportunity to get acquainted with the situation in the sphere of green deliveries, the authors aim to encourage a breakthrough in the field of sustainable transport that may be achieved by using cargo bikes in modern cities. We review the existing approaches and tools for modeling transport emissions and state the significant positive environmental consequences.]]>
<![CDATA[Operational problems of tramway infrastructure in sharp curves]]> Thu, 14 Oct 2021 08:36:02 +0200 Czyczuła, Włodzimierz; Rochel, Maciej
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Abstrakt: Elements of the tramway track that require special attention in the design and maintenance of the tramway infrastructure are sharp curves (curves with small radii). In such places, there are a number of unfavourable operational problems, which are discussed in the article below. It describes the characteristics of such geometric elements and analyses the interaction of the wheel-rail system. Moreover, the most important operational problems are presented, such as the wear of wheels and tramway rails, the buckling of the rails, and noise and vibrations occurring during the passage of the tram. Methods of reducing unfavourable phenomena occurring on curves in the tramway infrastructure were also highlighted.]]>
<![CDATA[Właściwości mechaniczne rur ze stali w gatunku Gr. 6 według ASTM A 333]]> Thu, 14 Oct 2021 08:32:51 +0200 Jonderko, Henryk; Psonka, Wojciech; Stankiewicz, Marek
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<![CDATA[Właściwości połączeń spawanych materiałów różnorodnych]]> Thu, 14 Oct 2021 08:27:51 +0200 Tasak, Edmund; Stankiewicz, Marek; Gierlicki, Ryszard; Ziewiec, Krzysztof
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<![CDATA[Zmiana własności plastycznych po spawaniu stali 2,25Cr-1Mo w czasie obróbki cieplnej]]> Thu, 14 Oct 2021 08:25:33 +0200 Stankiewicz, Marek; Tasak, Edmund
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<![CDATA[Połączenia spawane rur Gr. C/6/X52 wg ASTM i API – własności mechaniczne]]> Thu, 14 Oct 2021 08:23:03 +0200 Stankiewicz, Marek; Jonderko, Henryk; Kijowski, Dariusz; Psonka, Wojciech; Tasak, Edmund
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<![CDATA[Change in the ductility properties of 2,25Cr–1Mo steel during post-welding heat treatment]]> Thu, 14 Oct 2021 08:20:27 +0200 Stankiewicz, M.; Tasak E.
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<![CDATA[Ocena podstawowych właściwości stali S460M w szerokim zakresie temperatur obniżonych i podwyższonych]]> Thu, 14 Oct 2021 08:18:04 +0200 Stankiewicz, Marek
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<![CDATA[Porównanie wyników badań udarności stali konstrukcyjnych określonych w oparciu o normy PN-EN 10045-1 i ASTM E23]]> Thu, 14 Oct 2021 08:15:21 +0200 Stankiewicz, Marek; Ziółkowski, Eugeniusz
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<![CDATA[Kwasoodporna stal ASTM 304L o nietypowym stanie dostawy]]> Thu, 14 Oct 2021 08:11:50 +0200 Stankiewicz, Marek; Stępień, Tadeusz
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<![CDATA[Własności połączeń spawanych stali P22 po stopniowym chłodzeniu]]> Wed, 13 Oct 2021 14:50:23 +0200 Stankiewicz, Marek; Tasak, Edmund
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<![CDATA[S690QL – krajowa stal klasy N-A-XTRA]]> Wed, 13 Oct 2021 14:48:13 +0200 Stankiewicz, Marek; Prószyński, Maciej
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Abstrakt: W artykule przedstawiono wyniki badań fizykomechanicznych i strukturalnych stali S690QL, które wskazują na możliwość stosowania tej stali w wyższych temperaturach eksploatacji niż wynika to z zaleceń normy PN—EN 10137:2000. Jednocześnie wskazano na niedociągnięcia technologiczne w procesie wytwarzania skutkujące niedostateczną jednorodnością materiału.]]>
<![CDATA[PGS/HAp microporous composite scaffold obtained in the TIPS-TCL-SL method: an innovation for bone tissue engineering]]> Wed, 13 Oct 2021 13:18:15 +0200 Piszko, Paweł; Sobczak-Kupiec, Agnieszka
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Abstrakt: In this research, we synthesize and characterize poly(glycerol sebacate) pre-polymer (pPGS) (1H NMR, FTiR, GPC, and TGA). Nano-hydroxyapatite (HAp) is synthesized using the wet precipitation method. Next, the materials are used to prepare a PGS-based composite with a 25 wt.% addition of HAp. Microporous composites are formed by means of thermally induced phase separation (TIPS) followed by thermal cross-linking (TCL) and salt leaching (SL). The manufactured microporous materials (PGS and PGS/HAp) are then subjected to imaging by means of SEM and µCT for the porous structure characterization. DSC, TGA, and water contact angle measurements are used for further evaluation of the materials. To assess the cytocompatibility and biological potential of PGS-based composites, preosteoblasts and differentiated hFOB 1.19 osteoblasts are employed as in vitro models. Apart from the cytocompatibility, the scaffolds supported cell adhesion and were readily populated by the hFOB1.19 preosteoblasts. HAp-facilitated scaffolds displayed osteoconductive properties, supporting the terminal differentiation of osteoblasts as indicated by the production of alkaline phosphatase, osteocalcin and osteopontin. Notably, the PGS/HAp scaffolds induced the production of significant amounts of osteoclastogenic cytokines: IL-1β, IL-6 and TNF-α, which induced scaffold remodeling and promoted the reconstruction of bone tissue. Initial biocompatibility tests showed no signs of adverse effects of PGS-based scaffolds toward adult BALB/c mice.]]>
<![CDATA[Review of the applications of biomedical compositions containing hydroxyapatite and collagen modified by bioactive components]]> Wed, 13 Oct 2021 13:09:35 +0200 Sobczak-Kupiec, Agnieszka; Drabczyk, Anna; Florkiewicz, Wioletta; Głąb, Magdalena; Kudłacik-Kramarczyk, Sonia; Słota, Dagmara; Tomala, Agnieszka; Tyliszczak, Bożena
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Abstrakt: Regenerative medicine is becoming a rapidly evolving technique in today’s biomedical progress scenario. Scientists around the world suggest the use of naturally synthesized biomaterials to repair and heal damaged cells. Hydroxyapatite (HAp) has the potential to replace drugs in biomedical engineering and regenerative drugs. HAp is easily biodegradable, biocompatible, and correlated with macromolecules, which facilitates their incorporation into inorganic materials. This review article provides extensive knowledge on HAp and collagen-containing compositions modified with drugs, bioactive components, metals, and selected nanoparticles. Such compositions consisting of HAp and collagen modified with various additives are used in a variety of biomedical applications such as bone tissue engineering, vascular transplantation, cartilage, and other implantable biomedical devices.]]>
<![CDATA[Polymer-ceramic biocomposites based on PVP/histidine/hydroxyapatite for hard tissue engineering applications]]> Wed, 13 Oct 2021 13:02:08 +0200 Sobczak-Kupiec, Agnieszka; Tomala, Agnieszka Maria; López, Cristina Domínguez; Drabczyk, Anna; Tyliszczak, Bożena
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Abstrakt: Polymer and hydroxyapatite (HAP) composites have growing interest in bone regeneration. Commonly used for these applications is polyvinylpyrrolidone (PVP), which represents excellent biological inertness, is biocompatible, and do not adversely interact with HAP. For this reason, in our studies, we have focused on 3-igreedient biocomposites based on PVP/histidine/HAP investigating their mechanical performance, morphology, swelling property and incubation response. The objective is to determine the effect of histidine on the UV cross-linked hydroxyapatite-polymers composites particularly focused on the role of their composition on structure, mechanical properties, and biocompatibility. The results confirm bioactivity of this material and it desirable features for orthopedics.]]>
<![CDATA[Tradycja i współczesność w architekturze Zakopanego. Wybrane aspekty]]> Wed, 13 Oct 2021 12:32:28 +0200 Węcławowicz-Gyurkovich, Ewa; Godula-Węcławowicz, Róża
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Abstrakt: Drewniana architektura Zakopanego, intensywnie rozwijającego się z końcem XIX i w pierwszej dekadzie XX wieku, stanowi odmienny od innych regionów fenomen. Jest wypadkową tradycji kultury górali podhalańskich i motywów zaczerpniętych ze stylistyki historycznej, twórczo przetworzonych przez Stanisława Witkiewicza w oryginalny styl w architekturze i zdobnictwie. Styl zakopiański został zaadaptowany przez kolejne pokolenia Podhalan, którzy nadal uznają go za własny; co więcej, do dziś stanowi wzorzec dla architektów i projektantów. W nowych realizacjach w Zakopanem można zaobserwować rozmaite formy budynków – twórcze interpretacje stylu, realizacje kontrowersyjne albo powierzchownie nawiązujące do tradycji. Długie trwanie idei Witkiewicza wpisuje się w kulturową kategorię „tradycji wynalezionej”, rozumianej procesualnie, podlegającej przekształceniom i reinterpretacji.]]>
<![CDATA[Podstawowe własności mechaniczne stali S.A. 387 Gr.11 Cl.2 w podwyższonej temperaturze]]> Wed, 13 Oct 2021 11:16:59 +0200 Stankiewicz, Marek; Baran, Marek; Stępień, Tadeusz
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<![CDATA[Hierarchical FeCo/C@Ni(OH)2 heterostructures for enhanced oxygen evolution activity]]> Wed, 13 Oct 2021 10:19:54 +0200 Xie, Cong; Zhang, Xiao; Matras-Postolek, Katarzyna; Yang, Ping
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Abstrakt: Layered Ni(OH)2 nanosheets are considered as one of the most promising oxide evolution reaction (OER) catalysts due to its excellent oxidation and reduction reaction performance which has been extensively studied. However, there is a big gap between the Ni(OH)2 nanosheets and noble metal catalysts in terms of the OER activity which is difficult to meet the request of application. Here, a strategy was developed to deposit Ni(OH)2 nanosheets on FeCo/C nanocubes surface to create a hierarchical heterostructure as a new type of non-noble metal catalyst. The initial overpotential of the prepared FeCo/C@Ni(OH)2 catalyst is as low as 212 mV and the Tafel slope is smaller compared with the precursor materials. The composite materials revealed enhanced cycle stability which can maintain more than 90% of initial current density after running for 10 h under 100 mV overpotential. The improvement of OER activity is ascribed to the FeCo/C nanocubes, which can not only improve the charge transport of the material, but also prevent the agglomeration of Ni(OH)2 nanosheets. The exciting features of FeCo/C@Ni(OH)2 nanocomposite open up the possibilities of preparing efficient and stable non-noble metal catalysts for OER electrocatalysts.]]>
<![CDATA[Validation of a 1:8 scale measurement stand for testing airborne sound insulation]]> Wed, 13 Oct 2021 08:27:22 +0200 Szeląg, Agata; Baruch‐Mazur, Katarzyna; Brawata, Krzysztof; Przysucha, Bartosz; Mleczko, Dominik
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Abstrakt: This paper contains a detailed description of the design and validation of a measurement stand for testing the airborne sound insulation of specimens made at a small scale. The stand is comprised of two coupled reverberation rooms in which the geometry represents the full‐size reverberation rooms used at the AGH University of Science and Technology at a 1:8 scale. The paper proves that both the scaled measurement stand and the testing methodology conform to the ISO 10140 standards, and that the obtained measurement uncertainty does not exceed the maximum values specified in ISO 12999‐1. Moreover, the calculated uncertainty of measurements obtained for the 1:8 scale stand is comparable with the typical uncertainty given in ISO 12999‐1 and the uncertainty obtained on the full‐scale measurement stand. In connection with the above, the authors have proved that by using the scaled‐down measurement stands, one can obtain reliable and repeatable results of measurements of airborne sound insulation.]]>
<![CDATA[Smartphone-based human sitting behaviors recognition using inertial sensor]]> Wed, 13 Oct 2021 08:24:49 +0200 Kumar Sinha, Vikas; Kumar Patro, Kiran; Pławiak, Paweł; Jaya Prakash, Allam
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Abstrakt: At present, people spend most of their time in passive rather than active mode. Sitting with computers for a long time may lead to unhealthy conditions like shoulder pain, numbness, headache, etc. To overcome this problem, human posture should be changed for particular intervals of time. This paper deals with using an inertial sensor built in the smartphone and can be used to overcome the unhealthy human sitting behaviors (HSBs) of the office worker. To monitor, six volunteers are considered within the age band of 26 ± 3 years, out of which four were male and two were female. Here, the inertial sensor is attached to the rear upper trunk of the body, and a dataset is generated for five different activities performed by the subjects while sitting in the chair in the office. Correlation-based feature selection (CFS) technique and particle swarm optimization (PSO) methods are jointly used to select feature vectors. The optimized features are fed to machine learning supervised classifiers such as naive Bayes, SVM, and KNN for recognition. Finally, the SVM classifier achieved 99.90% overall accuracy for different human sitting behaviors using an accelerometer, gyroscope, and magnetometer sensors.]]>
<![CDATA[In search of effective UiO-66 metal-organic frameworks for artificial kidney application]]> Wed, 13 Oct 2021 08:21:39 +0200 Dymek, Klaudia; Kurowski, Grzegorz; Kuterasiński, Łukasz; Jędrzejczyk, Roman; Szumera, Magdalena; Sitarz, Maciej; Pajdak, Anna; Kurach, Łukasz; Boguszewska-Czubara, Anna; Jodłowski, Przemysław J.
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Abstrakt: The removal of uremic toxins from patients with acute kidney injury is a key issue in improving the quality of life for people requiring peritoneal dialysis. The currently utilized method for the removal of uremic toxins from the human organism is hemodialysis, performed on semipermeable membranes where the uremic toxins, along with small molecules, are separated from proteins and blood cells. In this study, we describe a mixed-linker modulated synthesis of zirconium-based metal–organic frameworks for efficient removal of uremic toxins. We determined that the efficient adsorption of uremic toxins is achieved by optimizing the ratio between −amino functionalization of the UiO-66 structure with 75% of −NH2 groups within organic linker structure. The maximum adsorption of hippuric acid and 3-indoloacetic acid was achieved by UiO-66-NH2 (75%) and by UiO-66-NH2 (75%) 12.5% HCl prepared by modulated synthesis. Furthermore, UiO-66-NH2 (75%) almost completely adsorbs 3-indoloacetic acid bound to bovine serum albumin, which was used as a model protein to which uremic toxins bind in the human body. The high adsorption capacity was confirmed in recyclability test, which showed almost 80% removal of 3-indoloacetic acid after the third adsorption cycle. Furthermore, in vitro cytotoxicity tests as well as hemolytic activity assay have proven that the UiO-66-based materials can be considered as potentially safe for hemodialytic purposes in living organisms.]]>
<![CDATA[Przyczyny pękania rur ze stali X20CrMoV121 podczas gięcia na zimno]]> Wed, 13 Oct 2021 08:18:18 +0200 Mazur, Marek; Stankiewicz, Marek
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<![CDATA[Mn:CsPbBr3 nanoplatelets for bright white-emitting displays]]> Tue, 12 Oct 2021 11:54:14 +0200 Zhao, Yubin; Xie, Cong; Zhang, Xiao; Matras-Postolek, Katarzyna; Yang, Ping
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Abstrakt: Controlled ion-exchange reactions endow CsPbX3 nanocrystals (NCs) with superior photoluminescence (PL) properties. In this study, MnX2 (X = Cl and Br) was used as the precursor of Mn for cation-exchange reactions to synthesize Mn-doped CsPbBr3 nanoplatelets (NPLs). The anion-derived cation-exchange reactions occur within a short period of time. The PL peaks of CsPbBr3 NPLs were adjusted from 460 to 500 nm (redshift) by controlling the thickness of NPLs. The ion-exchange process of MnBr2 and CsPbBr3 NPLs resulted in Mn doping because of the PL peak (∼610 nm) of Mn ions observed. With increasing MnBr2 incorporation, CsPbBr3 NPLs excited d-d transfer from Mn ions, resulting in an increased PL intensity of Mn ions. Two PL peaks from CsPbBr3 NPLs and Mn ions were obtained, in which the PL color of Mn:CsPbBr3 composites changed from blue to white. The PL quantum yield (PLQYs) of Mn:CsPbBr3 composites is up to 64.4%. Br ion-derived ion exchange plays an important role for Mn ions that enter the crystal lattices instead of Pb NPLs. After ion exchange, the morphology of the sample remained unchanged. However, the PLQYs of the sample increased. The average lifetimes of the sample depended strongly on the emission wavelength. With the increasing amount of Mn doping, the lifetime was increased to 1.63 ms (λem = 610 nm) from the ns level. A white-emitting sample with the Commission Internationale de I′Eclairage (CIE) coordinates of 0.3013 and 0.3089, as well as PLQYs of 95% were obtained by adding green-emitting CsPbBr3 nanocrystals in Mn:CsPbBr3 NPLs, suggesting an important application in displaying devices.]]>
<![CDATA[Mesoporous silica-coated CsPbX3 nanocrystals with high stability and ion-exchange resistance for bright white-emitting displays]]> Tue, 12 Oct 2021 11:28:33 +0200 Shi, Wenbin; Zhang, Xiao; Matras-Postolek, Katarzyna; Yang, Ping
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Abstrakt: All-inorganic metal halide perovskite (CsPbX3) nanocrystals (NCs) have attracted much attention due to their excellent photoelectric properties. However, CsPbX3 NCs are easily affected by polar solvents because of their ionic crystal nature, which led to luminescence quenching. In this paper, mesoporous silica nanoparticles (MSNs) were used as carriers to anchor CsPbX3 NCs for effectively improving the resistance of CsPbX3 NCs in polar solvents. CsPbX3@MSN composites were created via a sol–gel-assisted ligand exchanging process. The photoluminescence (PL) intensity of the CsPbX3@MSNs composite still maintained more than 50% of their initial value after 60 min of treatment with water and ethanol. The mesoporous structures of SiO2 spheres facilitate efficient coupling of CsPbX3 NCs to improve the stability and decrease surface defects, resulting in high PL quantum yield. CsPbX3@MSN composites have unique advantages for white-light-emitting diodes (LEDs) as solid-state luminescent materials. White LED devices were fabricated using CsPbX3@MSN composites as the solid-state light-emitting conversion layer. The color temperature was 6838 K, and the luminous efficiency was 8.9 lm/W. Its coincidence degree with the gamut space specified by NTSC 1953 is 135%, and the coincidence degree with the gamut space specified by ITU-R B.T. 2020 (Rec. 2020) is 95%.]]>
<![CDATA[A matrix FMEA analysis of variable delivery vane pumps]]> Tue, 12 Oct 2021 10:46:30 +0200 Fabiś-Domagała, Joanna; Domagała, Mariusz; Momeni, Hassan
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Abstrakt: Hydraulic systems are widely used in the aeronautic, machinery, and energy industries. The functions that these systems perform require high reliability, which can be achieved by examining the causes of possible defects and failures and by taking appropriate preventative measures. One of the most popular methods used to achieve this goal is FMEA (Failure Modes and Effects Analysis), the foundations of which were developed and implemented in the early 1950s. It was systematized in the following years and practically implemented. It has also been standardized and implemented as one of the methods of the International Organization for Standardization (ISO) 9000 series standards on quality assurance and management. Apart from wide application, FMEA has a number of weaknesses, which undoubtedly include risk analysis based on the RPN (Risk Priority Number), which is evaluated as a product of severity, occurrence, and detection. In recent years, the risk analysis has been very often replaced by fuzzy logic. This study proposes the use of matrix analysis and statistical methods for performing simplified RCA (Root Cause Analysis) and for classification potential failures for a variable delivery vane pump. The presented methodology is an extension of matrix FMEA and allows for prioritizing potential failures and their causes in relation to functions performed by pump components, the end effects, and the defined symptoms of failure of the vane pump.]]>
<![CDATA[Modelling of cnditional scalar dissipation rate in turbulent premixed combustion]]> Tue, 12 Oct 2021 10:42:45 +0200 Amzin, Shokri; Domagała, Mariusz
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Abstrakt: In turbulent premixed flames, for the mixing at a molecular level of reactants and products on the flame surface, it is crucial to sustain the combustion. This mixing phenomenon is featured by the scalar dissipation rate, which may be broadly defined as the rate of micro-mixing at small scales. This term, which appears in many turbulent combustion methods, includes the Conditional Moment Closure (CMC) and the Probability Density Function (PDF), requires an accurate model. In this study, a mathematical closure for the conditional mean scalar dissipation rate, , in Reynolds, Averaged Navier–Stokes (RANS) context is proposed and tested against two different Direct Numerical Simulation (DNS) databases having different thermochemical and turbulence conditions. These databases consist of lean turbulent premixed V-flames of the CH4-air mixture and stoichiometric turbulent premixed flames of H2-air. The mathematical model has successfully predicted the peak and the typical profile of with the sample space ζ and its prediction was consistent with an earlier study.]]>