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Recent items
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Tailoring a low-energy ball milled MnCo2O4 spinel catalyst to boost oxygen evolution reaction performance
- Sylwia Pawłowska
- Krystian Lankauf
- Patryk Błaszczak
- Jakub Karczewski
- Karolina Górnicka
- Grzegorz Cempura
- Piotr Jasiński
- Sebastian Molin
The development of cost-efficient oxygen evolution reaction (OER) catalysts is one of the most important tasks facing modern techniques for hydrogen production. In this work, for the first time, a low-energy ball milling process of MnCo2O4 (MCO) spinel powders, with a mechanical modification time exceeding 1 day was used. After 6 days of ball-milling, the obtained overpotential of the electrocatalyst reached the value of 375 mV at 10 mA cm-2, which is a relatively low value obtained for this type of compound. The studies showed how the mechanical (low-energy long-term milling process) and chemical modification of the fragmented spinel powder nanoparticle surfaces affects the increase of the electrocatalytic properties. The addition of the appropriate amount of conductive carbon black (cCB) and Nafion ionomer to the ink of the MCO spinel also has a significant effect on the improvement of the catalytic performance of the manganese-cobalt oxide during the milling process. By reducing the amount of Nafion to 10% of its initial value, the overpotential dropped to 352 mV at 10 mA cm-2 after 30 days of ball-milling. This shows that catalyst ink and layer composition are important factors influencing the catalyst’s efficiency in the OER
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Tailoring diamondised nanocarbon-loaded poly(lactic acid) composites for highly electroactive surfaces: extrusion and characterisation of filaments for improved 3D-printed surfaces
- Mateusz Cieślik
- Agnieszka Susik
- Mariusz Banasiak
- Robert Bogdanowicz
- Krzysztof Formela
- Jacek Ryl
A new 3D-printable composite has been developed dedicated to electroanalytical applications. Two types of diamondised nanocarbons - detonation nanodiamonds (DNDs) and boron-doped carbon nanowalls (BCNWs) - were added as fillers in poly(lactic acid) (PLA)-based composites to extrude 3D filaments. Carbon black served as a primary filler to reach high composite conductivity at low diamondised nanocarbon concentrations (0.01 to 0.2 S/cm, depending on the type and amount of filler). The aim was to thoroughly describe and understand the interactions between the composite components and how they affect the rheological, mechanical and thermal properties, and electrochemical characteristics of filaments and material extrusion printouts. The electrocatalytic properties of composite-based electrodes, fabricated with a simple 3D pen, were evaluated using multiple electrochemical techniques (cyclic and differential pulse voltammetry and electrochemical impedance spectroscopy). The results showed that the addition of 5 wt% of any of the diamond-rich nanocarbons fillers significantly enhanced the redox process kinetics, leading to lower redox activation overpotentials compared with carbon black–loaded PLA. The detection of dopamine was successfully achieved through fabricated composite electrodes, exhibiting lower limits of detection (0.12 μM for DND and 0.18 μM for BCNW) compared with the reference CB-PLA electrodes (0.48 μM). The thermogravimetric results demonstrated that both DND and BCNW powders can accelerate thermal degradation. The presence of diamondised nanocarbons, regardless of their type, resulted in a decrease in the decomposition temperature of the composite. The study provides insight into the interactions between composite components and their impact on the electrochemical properties of 3D-printed surfaces, suggesting electroanalytic potential.
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Tailoring optical constants of few-layer black phosphorus coatings: Spectroscopic ellipsometry approach supported by ab-initio simulation
- Aleksandra Wieloszyńska
- Krzysztof Pyrchla
- Paweł Jakóbczyk
- Dawid Lentka
- Mirosław Sawczak
- Łukasz Skowroński
- Robert Bogdanowicz
2D black phosphorus (BP) has attracted extensive attention as an anisotropic platform for novel optoelectronic and polarizing optics applications. Insight into the factors that tune the optical and polarizing properties of 2D BP reveals their essential influence on BP-based photonic and optoelectronic devices. In this work, studies of the optical constants of few-layer black phosphorus coatings are studied and discussed, with particular emphasis on the complex dielectric function. Herein, the complex optical constants of multi-flake composite films in the energy range of 1.38–6.2 eV by spectroscopic ellipsometry with the use of the classical optical model have been determined. Classical optical simulations were supplied by dielectric function estimations delivered by density functional theory. Additionally, few-layer black phosphorus coatings were imaged by polarizing microscopy and investigated by Raman spectroscopy, revealing a size-tunable flake composition. The pattern analysis of the polarization images reveals a shift in polarization anisotropy originated mainly from the central region of the flake. The semi-isotropic optical properties suggest that the extinction coefficient of BP flakes defines the applications of BP in photonics, waveguides, and directional optoelectronic devices.
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Tam gdzie fikcja spotyka się z rzeczywistością
- Jacek Lebiedź
Na tyłach budynku A Wydziału Elektroniki, Telekomunikacji i Informatyki (tego z zerami i jedynkami na elewacji) mieści się laboratorium odmienne wyglądem od innych laboratoriów politechnicznych. Zajmuje ono sięgającą czwartego piętra czarną sześcienną kostkę dobudowaną 10 lat temu w bezpośrednim sąsiedztwie audytorium, któremu od dwóch lat patronuje doc. Marianna Sankiewicz, przysiadłszy na ławeczce przed jego wejściem. Wydaje się, że nie tylko zaprasza do audytorium, ale również do wspomnianego wyżej nietypowego laboratorium, do którego prowadzą drzwi przed wejściem do audytorium.
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Targeting Spike‐ACE2 Interface of SARS‐CoV‐2 and its Omicron Variant: A Comparative Screening of Potential Inhibitors for Existing and Anticipating Variants Using Molecular Modelling Approach
- Dineshbabu Takkella
- Sudhanshu Sharma
- Radosław Krzemieniecki
- Ashok Pabbathi
- Subrahmanyam Sappati
- Krishna Gavvala
The recent COVID pandemic has shown major impact on public health and economic crisis. Despite the development of many vaccines and drugs against the severe acute respiratory syndrome (SARS) coronavirus 2, the pandemic still persists. The continued spread of the virus is largely driven by the emergence of viral variants such as α, β, γ, delta, epsilon spike, omicron and its subvariants (BA.1,2,3) which can evade the current vaccines through mutations in the spike protein.[1] For instance, spike to omicron has modifications at different mutations (D405N, K417N, S477N, E484A, Q493R, N501Y, Y505H).[1b] These mutations will affect functional properties and hence may alter the specificity towards potential drug candidates. Therefore, it is important to understand the role of these mutations on interactions with existing drug candidates. In this study, we focus on the two forms of SARS-CoV-2, such as wild-type spike and omicron and unveil their interactions with different drugs. For this purpose, we have taken about hundred drugs categorised in twelve groups of anticancer, natural products, enzyme inhibitors, antivirals, antioxidants, anti-bacterials, anti-malarials, antidiabetics, antimicrobials, anti-inflammatory, antifungals and other drugs. We used in-silico methods to understand the effect of these drug molecules on wild type and omicron spike RBD at the interface of ACE2 enzyme. Based on molecular docking results, we have chosen 7 best docked compounds and studied their interaction patterns in detail by molecular dynamics simulation.
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Technical and economic analysis of energy storage in the compressed air technology with low capacity for the production plant
- Krzysztof Kosowski
- Marian Piwowarski
- Wojciech Włodarski
- Paweł Ziemiański
- Gabriel Pawlak
Compressed air energy storage (CAES) system is a promising technology due to its numerous advantages, including relatively low maintenance cost, a long lifespan and high operational flexibility. This article explores the possibility of designing a CAES power plant as a source of electricity and heat for an existing industrial plant. The study involves the technical analysis of the power plant parameters and the economic analysis of the pro- ject’s feasibility. The proposed power plant is an innovative solution with an air expander with an external combustion chamber and a bypass that allows the combustion of virtually any fuel, making it particularly environmentally friendly. In the system, the use of a combustion chamber at the outlet of the turbine makes the chamber operate at a constant pressure that is close to atmospheric pressure. The designed power plant has a capacity of approx. 3.1 MW. Turbine operation reaches an efficiency of about 76%. Additional modification of the power plant and the use of heat from compressor cooling could increase the power of the power plant by about 0.5 MW. The conducted financial analysis showed that the project is economically feasible under the adopted assumptions in three modeled scenarios. Under the most optimistic scenario, the internal rate of return (IRR) reached 14.27%, and the investment return time was 10 years. When using long-term energy prices data, it was 7.46% and 23 years, respectively. The proposed CAES system is original and competitive in comparison to the currently used solutions.
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Techniki zwiększania efektywności metody elementów skończonych poprzez redukcję dziedziny obliczeniowej z wykorzystaniem własności geometrii struktur
- Małgorzata Warecka
Współczesna elektronika ze względu na swój szybki rozwój wymaga od nas efektywnego modelowania zjawisk polowych. Celem rozprawy jest zwiększanie efektywności metody elementów skończonych poprzez redukcję dziedziny obliczeniowej z wykorzystaniem własności geometrii struktur oraz jej hybrydyzację z użyciem technik analitycznych. Rozprawa zawiera przegląd stanu wiedzy na temat dostępnych obecnie technik modelowania jak również opis kluczowych aspektów metody elementów skończonych. W ramach przeprowadzonych badań powstało pięć algorytmów, które obejmują zarówno rozpraszanie fali elektromagnetycznej jak i analizy prowadnic falowych czy struktur rezonansowych. Zaprezentowane techniki wykorzystują między innymi symetrię osiową czy dekompozycję dziedziny. Praca zawiera hybrydyzację metody elementów skończonych wykorzystującą uogólnioną macierz impedancji, która pozwala w łatwy sposób modelować otwartą przestrzeń. Przebadane zostały również ograniczenia związane z jej wykorzystaniem do modelowania struktur periodycznych w porównaniu z periodycznymi warunkami brzegowymi. Praca obejmuje dwie struktury rezonansowe, przy czym jedna z nich wymaga rozwiązania nieliniowego problemu własnego. Dla wszystkich zaproponowanych technik w celu potwierdzenia poprawności prezentowanych podejść, otrzymane wyniki porównano z rezultatami dostępnymi w literaturze oraz otrzymanymi innymi uznanymi metodami.
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Technique for reducing erosion in large-scale circulating fluidized bed units
- Jarosław Grochowalski
- Agata Widuch
- Sławomir Sładek
- Bartłomiej Melka
- Marcin Nowak
- Adam Klimanek
- Marek Andrzejczyk
- Marcin Klajny
- Lucyna Czarnowska
- Bartłomiej Hernik
- Zhou Minmin
- Sebastian Pawlak
- Wojciech Adamczyk
This paper presents a methodology, implemented for a real industrial-scale circulating fluidized bed boiler, to mitigate the risk of heating surfaces exposed to an intensive particle erosion process. For this purpose, a machine learning algorithm was developed to support the boiler reliability management process. Having a tool that can help mitigate the risk of uncontrolled power unit failure without expensive and technically complex modernization is desired. A virtual procedure can be seen as a milestone towards the application of digital models to the diagnostic procedure of large power units, providing answers for many scenarios that cannot be normally studied during boiler operation. The predictive model developed in this work allows us to provide the requested feedback to the unit control systems regarding possible changes in boiler operating conditions and reduce the erosion effect. The functionality of the discussed methodology is investigated via application of the developed multiphase computational model.
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Techno-economic assessment of cooperation of hybrid renewable energy sources with hydrogen storage
- Jakub Łukasik
- Marcin Jewartowski
- Jan Wajs
The paper presents a technical and economic analysis of the power supply for a model industrial facility with the use of the most promising renewable energy sources (RES), supported by a hydrogen energy storage. This scenario was compared with the variants of supplying the facility directly from the grid and from RES without energy storage. A strategy was proposed for powering the plant aimed at maximising self-consumption of self-generated electricity. In this paper the importance of hybrid renewable energy systems (HRES) with hydrogen energy storage in the Polish Power System is pointed out. For the analysed industrial object, the modelling and optimisation of the systems were performed in the HOMER software, in terms of the lowest net present cost. Attention was also paid to the need to compress hydrogen and the associated electricity consumption.
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Techno-economic evaluation of combined cycle gas turbine and a diabatic compressed air energy storage integration concept
- Sylwia Kruk-Gotzman
- Iliya Iliev
- Gabriel-Paul Negreanu
- Janusz Badur
- Paweł Ziółkowski
More and more operational flexibility is required from conventional power plants due to the increasing share of weather-dependent renewable energy sources (RES) generation in the power system. One way to increase power plant’s flexibility is integrating it with energy storage. The energy storage facility can be used to minimize ramping or shutdowns and therefore should lower overall generating costs and CO2 emissions. In this article, we examined the effects of a combined cycle gas turbine (CCGT) power plan and a compressed air energy storage (CAES) system integration. The main feature of the CCGT-CAES integration concept is using the CCGT installation as a heat recipient and provider for the CAES installation. This approach was applied to a real-life case study of the PGE Gorz´ow CCGT power plant. First, technical feasibility of itegrating a CCGT plant with a CAES system was verified and the restrictions on the operating conditions were identified. Next, the improvement in flexibility was quantified by the additional profits gained from the integration. Polish day-ahead electricity prices were used as a measure for remunerating flexibility. Two models were developed in the Python computer programming language: a thermodynamic one and an economic one. The former was buit without the use of flowsheeting software or purpose-built industry specific tool. The latter was implemented within the frame of the PuLP library and solved using its default solver (CBC). By means of mixed integer linear programming (MILP) optimal generation schedules and maximum profits were found for three cases: an independent operation of the CCGT, an integrated CCGT-CAES plant and an integrated CCGT-ES plant with 81% storage efficiency. The results of the computational simulations contradict the supposition that the integration is economically viable, even if mechanical energy storage efficiency of 81% is assumed. Regarding the impact of the integration on the optimal schedule, although it is negligible for the 56% mechanical energy storage efficiency case, a significant change in operation profiles is observed for the 81% case. The model developed here can be used either when making decisions about investment in flexibility improvements or for planning daily operation of a generating unit.
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Technological solutions for boosting hydrogen role in decarbonization strategies and net-zero goals of world shipping: Challenges and perspectives
- Anh Tuan Hoang
- Ashok Pandey
- Francisco Javier Martinez De Osés
- Wei-Hsin Chen
- Zafar Said
- Kim Hoong Ng
- Ümit Ağbulut
- Wiesław Tarełko
- Aykut I. Ölçer
- Xuan Phuong Nguyen
Facing the problems concerning greenhouse gas (GHG) emissions from international ocean shipping has meant that the latest regulations of the International Maritime Organization, issued on 1st January 2023, have come into force, with the aim of reducing GHG emissions from maritime activities. Hydrogen has been suggested as an alternative fuel to achieve decarbonization ambitions in the near future. Although hydrogen has been investigated and developed over the years, its application in ocean freight is still at an embryonic stage, with a very limited number of studies exploring its feasibility. Therefore, this work comprehensively reviewed the pertinent knowledge in the field, associated with the production, storage, and energy-derivation of hydrogen on ships and aims to identify the potential issues and provide possible solutions for fueling the shipping industry with hydrogen energy. It was found that the under-par development of hydrogen-based energy for the shipping industry can be explained by the following reasons: (i) the inability of space-limited ships to use the currently available hydrogen technologies; (ii) difficulties in hydrogen storage; (iii) under-developed infrastructure at hydrogen-bunkering ports; (iv) high retrofitting, maintenance, and operating costs; (v) incomplete guidelines, international rules and regulations for the implementation of hydrogen in fueling global shipping; and (vi) cheaper conventional fuels leading to the reluctancy of industry players to become involved in such a green transition. Finally, several suggestions relating to technological aspects and policy implications were given aiming at advocating the green transition of hydrogen-powered maritime industries for cleaner and more sustainable global trading.
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Technological vs. Non-Technological Mindsets: Learning From Mistakes, and Organizational Change Adaptability to Remote Work
- Wioleta Kucharska
- Maciej Kucharski
The permanent implementation of the change in working methods, e.g., working in the virtual space, is problematic for some employees and, as a result, for management leaders. To explore this issue deeper, this study assumes that mindset type: technological vs. non-technological, may influence the organizational adaptability to change. Moreover, the key interest of this research is how non-technological mindsets adapt to remote work in the long run. Based on the OLS regression (SPSS PROCESS), authors analyze three data sets gathered via the questionnaire distributed using the CAWI method among Polish knowledge workers; the first data set was gathered in December 2019 before the COVID-19 crisis, and the next in 2021 and 2022. Findings revealed that before COVID-19, high intensity of contacts via technology-supported change adaptability only for the IT industry. Results obtained two and three years later exposed that interactions via technology also increased the change adaptability in other sectors. This study confirms that the technological environment can change the employee mindset. Nevertheless, at the same time, the adaptability process can be prolonged and complex even for highly educated knowledge workers’ groups. Since there is no development without technology today - patience and long-run perspective thinking are recommended to achieve sustainable growth. It is critical. Adaptation to technology-dominated virtual workspaces must continue, even if this is problematic for non-technological mindsets; abandoning this idea will only make the inevitable transformation longer and more challenging. Collective intelligence creation requires inclusion and patience instead of exclusion of those who face problems or abandonment of change when facing implementation problems rooted in mindsets.
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Technologies for Joining and Forming Thin-Walled Structures in the Construction of Transportation Vehicles
- Dariusz Fydrych
- Andrzej Kubit
- Ján Slota
- Agnieszka Kowalczyk
Editorial
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Technology adoption review for ageing well: analysis of technical solutions
- Ishaya Gambo
- M. Victoria Bueno-Delgado
- Kerli Mooses
- Francisco J. Melero Muñoz
- Rina Zviel-Girshin
- Aliaksei Andrushevich
- Michael Mrissa
- Agnieszka Landowska
- Kuldar Taveter
While several technological solutions are available for older adults to improve their wellbeing and quality of life, little is known about the gaps between the needs, provided solutions, and their adoption from a more pragmatic perspective. This paper reports on reviewing existing technological solutions for older adults, which span the work life, life in the community, and wellbeing at home. We analyzed 50 different solutions to uncover both negative and positive features of these solutions from the perspective of the impact of technology adoption on the quality of life of older adults. Our approach harnesses holistic reasoning to determine the most suitable technologies available today and provides suggestions for improvement toward designing and implementing better solutions.
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Technology brands in the digitally-based and network economy. Setting the background
- Wioleta Kucharska
- Ewa Lechman
This chapter defines and draws a general picture on Digital Technologies and Technology Brands’ meaning in the current economy. It contextualises the role and channels of digital technology’s impact on their shaping technology brands in network economy. It briefly explains why digital, innovative technologies constitute a perfect background and environment for technology brands of global scope. It discusses the place of technology brands in modern and technology-driven economies, showing their contribution to economic activities, jobs creation, and business running modes—both in economic and managerial terms. Furthermore, it proposes further studies directions.
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Technology-Enhanced Environmental Learning: Co-design of Educational Mobile Application Case
- Jolanta Kowal
- Helena Anacka
- Iwona Nowakowska
- Ewa Duda
- Hanna Obracht-Prondzyńska
The process of co-creating an educational mobile application to support environmentally friendly behavior is presented in this paper. The research material consisted of quantitative data collected on the application during the first testing phase by early adopters. The results suggest that the most frequently used features of the app were related to transport and educational activities. While women tended to split their time between transport and learning, men focused mainly on transport. This study contributes to the growing field of the use of educational mobile applications for the promotion of environmentally friendly behavior. The study results can support the design and development of future applications that encourage sustainable practices, benefit society, and contribute to a more sustainable future.
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Telomerase inhibition - unfulfilled hopes in the perfect molecular target
- Natalia Maciejewska
Telomerase plays a pivotal role in cell proliferation, homeostasis, and neoplastic transformation, making it a promising molecular target for cancer chemotherapy. Of note, although hTERT has been explored thoroughly as a target, none of the promising molecules has been approved as a drug until now. The subject of research conducted as part of my doctoral dissertation is explaining the cellular and molecular mechanism of action of new heterocyclic compounds derived from the class of carbazole, pyrazole, and anthraquinone. Of all the candidates tested, only anthraquinones inhibited telomerase activity. I have shown that the most active compound (TXT4), apart from the typical features of telomerase targeting molecules, also preferentially damages DNA on telomeres. Furthermore, I have found that TXT4 has an additional mechanism of action, consisting of multidirectional inhibition of tyrosine kinases. From among carbazoles, I selected compounds 5aa and 8, which primary mechanism of action is reactive oxygen species production. In addition, I showed that the most promising compound from the pyrazole class is PCH-1, whose anticancer activity is based on the stabilization of tubulin polymerization - the cytoskeleton-forming protein. On the basis of the conducted research, I determined the main mechanisms of action of new anti-cancer compounds, which in the future may employ as the basis for the design and synthesis of new potential pharmaceutical agents.
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Temperature Evolution, Material Flow, and Resulting Mechanical Properties as a Function of Tool Geometry during Friction Stir Welding of AA6082
- Aleksandra Laska
- Behzad Sadeghi
- Behzad Sadeghian
- Aboozar Taherizadeh
- Marek Szkodo
- Pasquale Cavaliere
The friction stir welding process was simulated for joining AA6082 aluminum alloy with the use of the computational fluid dynamics method. Two different tool geometries were used—a tapered cylindrical pin (simple pin) and a hexagonal pin with grooves (complex pin). The analysis of the simulations performed was discussed in terms of temperature evolution during the process, total heat input, residual stresses and material flow. Simulations revealed that a 5% higher temperature, equal to maximum 406 °C, was provided when using the complex pin than with the simple pin. Higher temperature and higher shear stresses during the welding with the complex pin caused the introduction of higher residual stresses in the weld. Experimental results on the produced welds allowed observation of the microstructure of the joints, hardness tests in cross sections and tensile strength tests. Due to the higher temperature during the process with the complex pin and the more efficient recrystallization process, grain refinement in the SZ was more pronounced. The average grain size in the stir zone for the weld produced with the complex pin was equal to 11 ± 1 µm, and in the case of the simple pin 14 ± 1 µm. The presented hardness profiles revealed that the weld produced with a complex pin had higher hardness in the stir zone, equal to 89.5 ± 1.3 HV, which is consistent with the Hall-Petch relationship. The obtained UTS values corresponded to the joint efficiency of 72.5 ± 4.9% and 55.8 ± 8.6% for the weld produced with the complex pin and the simple pin.
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Tensile and flexural moduli for human orbital wall bones – comparative study
- Paweł Lemski
- Krzysztof Żerdzicki
- Paweł Kłosowski
- Andrzej Skorek
- Marcin Zmuda Trzebiatowski
The main aims of the current research were: (1) to analyze in detail the tensile modulus and ultimate tensile strength (UTS) of orbital wall bones separately for the left and right orbit of the same cadaver and (2) to compare the obtained results with a flexural modulus of the left and right orbit reported earlier by A. C. van Leeuwen et al. [14]. A set of 54 specimens of orbital superior and/or medial walls harvested from 16 human skulls (4 female, 12 male) were tensioned at 0.01 mm/s till fracture. The samples were taken always from both orbits of the same cadaver. For each sample, cross-section area, apparent density, tensile modulus, and UTS were identified. For pooled female and male group apparent density for right and left orbit was identified to be 1.59 (± 0.52 SD) g/cm3 and 1.51 (±0.48 SD) g/cm3, tensile modulus of 2028 (±1729 SD) MPa and of 2706 (±2812 SD) MPa, and UTS of 14.17 (±15.00 SD) MPa and of 15.03 (±11.44 SD) MPa, respectively. For tensile tests, there were no statistical differences between the left and right orbit for pooled male and female groups for (a) apparent density (Student’s t-test p = 0.567), (b) UTS (Mann–Whitney U-test p = 0.350) and (c) tensile modulus (Mann–Whitney U-test p = 0.716). For bending tests, there were no statistical differences between the left and right orbit for the pooled male and female group for (a) orbital wall thickness (Student’s t-test p = 0.811) and (b) flexural modulus (Mann–Whitney U-test p = 0.206). The comparative analysis between tensile and flexural moduli for pooled left and right groups (with no distinction for male and female) revealed no statistically significant difference (Mann–Whitney U-test p = 0.074). The maximum tensile modulus was 7279 MPa and 9913 MPa for the right and left orbit, respectively, and was similar to the maximum flexural modulus of 6870 MPa and 9170 MPa reported in an earlier study, for the right and left orbit, respectively.
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Teoretyczno-doświadczalne modelowanie konwekcji wymuszonej nanocieczy
- Przemysław Kozak
Przedłożona rozprawa doktorska dotyczy badań eksperymentalnych oraz numerycznych konwekcji wymuszonej nanocieczy. Badane nanociecze wytworzone były z cieczy bazowych takich jak woda demineralizowana i mieszaniny wody z glikolem etylenowym w trzech proporcjach objętościowych 90:10, 80:20 i 60:40. Jako nanocząstki użyto Al2O3, a wytworzone nanociecze miały koncentracje masowe 0,1%, 1% i 5%. Wyznaczono eksperymentalnie dynamiczny współczynnik lepkości oraz współczynnik przewodzenia ciepła badanych nanocieczy. Wyznaczono współczynnik intensyfikacji cieplno-hydraulicznej badanych nanocieczy. Wyniki eksperymentalne porównano z wynikami obliczeń numerycznych.
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Terminal charging scheduling of battery electric buses based on vehicle routing problem
- Bálint Csonka
- Mikołaj Bartłomiejczyk
Electric buses are considered to be a viable solution for reducing emission in dense urban areas. However, the greater charging time is a huge challenge for operators. In this paper, charging scheduling method was elaborated based on vehicle routing problem using mixed-integer linear programming model. The main novelty of the paper is the combination of modelling aspect, namely flexible turn sequence and heterogeneous shared charging infrastructure. It was found that the method helps to reduce dwelling time and the number of buses in operation. In the future, we plan to integrate driver regulations, heterogeneous bus fleet, multiple depots and terminals into the model.
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Testing of Technical Fabrics under Fast Camera Control
- Paweł Kłosowski
- Krystyna Michałowska
- Marek Przyborski
- Wojciech Jurczak
The dynamic development of measurement and recording techniques has been changing the way one conceives material strength. In this study, two different methods of evaluating the strength of fabrics are compared. The first is the typical and commonly used technique based on the use of a testing machine. The second method uses the so-called “fast camera” to monitor the entire process of the destruction of a fabric sample and analyse the behav-iour of the fabric during the experiment. Both methods provide interesting data and present a very specific way of experimentally evaluating the strength of fabrics.
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Testing the Effect of Bathymetric Data Reduction on the Shape of the Digital Bottom Model
- Wiktor Mujta
- Marta Wlodarczyk-Sielicka
- Andrzej Stateczny
Depth data and the digital bottom model created from it are very important in the inland and coastal water zones studies and research. The paper undertakes the subject of bathymetric data processing using reduction methods and examines the impact of data reduction according to the resulting representations of the bottom surface in the form of numerical bottom models. Data reduction is an approach that is meant to reduce the size of the input dataset to make it easier and more efficient for analysis, transmission, storage and similar. For the purposes of this article, test datasets were created by discretizing a selected polynomial function. The real dataset, which was used to verify the analyzes, was acquired using an interferometric echosounder mounted on a HydroDron- 1 autonomous survey vessel. The data were collected in the ribbon of Lake Klodno, Zawory. Data reduction was conducted in two commercial programs. Three equal reduction parameters were adopted for each algorithm. The research part of the paper presents the results of the conducted analyzes of the reduced bathymetric datasets based on the visual comparison of numerical bottom models, isobaths, and statistical parameters. The article contains tabular results with statistics, as well as the spatial visualization of the studied fragments of numerical bottom models and isobaths. This research is being used in the course of work on an innovative project that aims to develop a prototype of a multi-dimensional and multi-temporal coastal zone monitoring system using autonomous, unmanned floating platforms at a single survey pass.
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Textile reinforced concrete members subjected to tension, bending, and in-plane loads: Experimental study and numerical analyses
- Adam Ścięgaj
- Sebastian Almfeldt
- Fredrik Larsson
- Karin Lundgren
Textile reinforced concrete has raised increasing research interest during the last years, mainly due to its potential to be used for freeform shell structures involving complex load situations. Yet, most experimental work has focused on test setups with primarily uniaxial loading. In the current work, such setups are complemented with a novel test setup of deep beams, including in-plane bending and shear. Further, nonlinear finite element analyses were carried out, applying an earlier calibrated bond-slip relation and efficiency factors for strength and stiffness of the textile reinforcement. It was found that the structural behaviour in terms of the overall stiffness, ultimate load and deformation, number of cracks, and total (summed) crack width, could be described with reasonably good accuracy. The inclusion of a calibrated efficiency factor for the stiffness of the yarn was shown to be vital. Moreover, it was shown to be important to weaken and randomise the material properties of the concrete at the location of transverse yarns, to trigger localisation (cracking) in the numerical model.
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Texture or Linker? Competitive Patterning of Receptor Assembly toward Ultra-Sensitive Impedimetric Detection of Viral Species at Gold-Nanotextured Titanium Surfaces
- Wiktoria Lipińska
- Adrian Olejnik
- Monika Janik
- Mateusz Brodowski
- Karolina Sapiega
- Mattia Pierpaoli
- Katarzyna Siuzdak
- Robert Bogdanowicz
- Jacek Ryl
In this work, we study the electrodes with a periodic matrix of gold particles pattered by titanium dimples and modified by 3-mercaptopropionic acid (MPA) followed by CD147 receptor grafting for specific impedimetric detection of SARS-CoV-2 viral spike proteins. The synergistic DFT and MM/MD modeling revealed that MPA adsorption geometries on the Au–Ti surface have preferential and stronger binding patterns through the carboxyl bond inducing an enhanced surface coverage with CD147. Control of bonding at the surface is essential for oriented receptor assembling and boosted sensitivity. The complex Au–Ti electrode texture along with optimized MPA concentration is a crucial parameter, enabling to reach the detection limit of ca. 3 ng mL–1. Scanning electrochemical microscopy imaging and quantum molecular modeling were performed to understand the electrochemical performance and specific assembly of MPA displaying a free stereo orientation and not disturbed by direct interactions with closely adjacent receptors. This significantly limits nonspecific interceptor reactions, strongly decreasing the detection of receptor-binding domain proteins by saturation of binding groups. This method has been demonstrated for detecting the SARS virus but can generally be applied to a variety of protein–antigen systems. Moreover, the raster of the pattern can be tuned using various anodizing processes at the titania surfaces.
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The accessibility, necessity, and significance of certified reference materials for total selenium content and its species to improve food laboratories' performance
- Chintankumar Padariya
- Małgorzata Rutkowska
- Piotr Konieczka
Micronutrients are one of the most important groups of nutrients that our body needs daily in trace amounts to tackle deficiencies. Selenium (Se) is a mineral that occurs naturally in foods and is an essential component of selenoproteins that support the healthy functioning of the human body. Therefore, monitoring dietary Se concentrations must be a higher priority to meet daily intakes. Fulfillment can be addressed through applying various analytical techniques, and the certified reference materials (CRMs) tool plays a crucial role in quality assurance/quality control (QA/QC). The availability of certified CRMs for total Se content with addition to their species is presented. The review emphasizes the necessity of incorporating more food matrix CRMs certifying Se species, apart from total Se content, to meet method validation requirements for food analysis laboratories. This would help CRM producers bridge the gap between available food matrix materials that are not certified for Se species.
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The Action Mechanisms, Anti-Cancer and Antibiotic-Modulation Potential of Vaccinium myrtillus L. Extract
- Mikayel Ginovyan
- Anush Babayan
- Anahit Shirvanyan
- Alvard Minasyan
- Barbara Kusznierewicz
- Izabela Koss-Mikołajczyk
- Anne Vejux
- Agnieszka Bartoszek-Pączkowska
- Naira Sahakyan
Herbal medicinal products containing Vaccinium myrtillus L. (bilberry) fruits and fruit extracts are widely available in the market. Although bilberry leaves and stems are considered as bio-waste, they contain much higher levels of phenolic compounds than fruits. The study aimed to investigate the antimicrobial and anticancer potential of aerial part extracts from Vaccinium myrtillus L. (V. myrtillus, VM) plants harvested at high altitudes in Armenian landscape and characterize the bioactive phytochemicals. For evaluation of antioxidant properties, chemical-based tests (total phenolic and flavonoid content, and antiradical activity in 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) tests) and cellular antioxidant activity (CAA) assay were applied. Genotoxicity and anticancer properties of the extract alone and in combination with fluorouracil were explored in human cancer and normal cell lines. Antibacterial properties of V. myrtillus ex- tract alone and in combination with antibiotics, as well as their effect on proton-flux rate through cell membrane were explored on bacterial strains. The characterization of active phytochemicals was done using Liquid Chromatography-Quadrupole-Orbitrap High-Resolution Mass Spectrometry (LC-Q-Orbitrap HRMS).The V. myrtillus aerial part extract demonstrated promising antioxidant properties in all tests. The selective cytotoxic activity was documented against various cancer cell lines (human colon adenocarcinoma (HT29), human breast cancer (MCF- 7) and human cervical carcinoma (HeLa)), while it did not inhibit the growth of tested human normal primary renal mixed epithelial cells (HREC) even at 10-fold higher concentrations. The extract did not have genotoxic properties in comet assay making it a potential source for the development of anticancer preparations. The investigated extract did not directly inhibit the growth of Escherichia coli (E. coli) and Salmonella typhimurium (S. typhimurium) strains at up to 1 mg/mL concentration. However, V. myrtillus extract enhanced the kanamycin intake and increased its efficiency against E. coli strain. The phytochemical characterization of the extract showed the presence of different groups of phenolics. Based on obtained data, we suggest the aerial parts of the V. myrtillus plant as an alternative source of bioactive natural products for food supplements, nutraceuticals, functional foods and medicine.
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The Application of Cluster Analysis in the Assessment of the Weldability of Unalloyed Steels
- Anna Szewczyk
- Klaudia Górska
- Adrian Wolski
- Dariusz Fydrych
Non-alloy steels constitute a large group of steels characterised by diversified chemical composition, structural morphology and a wide range of mechanical properties (determining weldability). The paper presents results of multidimensional analyses (based on cluster analysis) of 110 selected unalloyed steel grades. Properties adopted as diagnostic features included the chemical composition, mechanical properties (yield point) and values of selected indicators concerning susceptibility to technological crack formation. The analyses (performed using Ward’s and k-means methods) resulted in a division of the 110 steels into five steel groups (clusters). The comparison of results obtained using two clustering methods and involving various classification criteria revealed that multidimensional analyses constituted a prospective method making it possible to assess the weldability of steels. However, results of such multidimensional analyses should be subjected to thorough and substantive analyses.
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The Application of Dynamic Electrochemical Impedance Spectroscopy (DEIS) Technique in Corrosion and Corrosion Inhibition Studies
- Paweł Ślepski
- Husnu Gerengi
- Moses Solomon
- Saviour Umoren
orrosion studies have attracted considerable interest in the areas of materials chemistry and industrial chemistry, as it affects the direct and indirect costs of industry, leading to huge economic setbacks due to the need for repair, maintenance, and even shutdowns due corrosion damage. This new volume is a comprehensive resource that presents new and up-to-date, theoretical, and experimental corrosion inhibition studies.
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The Arnold conjecture in $ \mathbb C\mathbb P^n $ and the Conley index
- Luca Asselle
- Marek Izydorek
- Maciej Starostka
n this paper we give an alternative, purely Conley index based proof of the Arnold conjecture in CP^n asserting that a Hamiltonian diffeomorphism of CP^n endowed with the Fubini-Study metric has at least (n+1) fixed points.
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The assessment of solar photovoltaic in Poland: the photovoltaics potential, perspectives and development
- Bartłomiej Igliński
- Grzegorz Piechota
- Urszula Kiełkowska
- Wojciech Kujawski
- Michał Bernard Pietrzak
- Mateusz Skrzatek
The following article explains the current condition of the photovoltaics sector both in Poland and worldwide. Recently, a rapid development of solar energy has been observed in Poland and is estimated that the country now has about 700,000 photovoltaics prosumers. In October 2021, the total photovoltaics power in Poland amounted to nearly 5.7 GW. The calculated technical potential of photovoltaics in Poland is 153.484 PJ (42.634 TWh). This would cover 26.04% of Poland’s electricity needs. The main aim of the article is to assess the level of development of the photovoltaic market in Poland, the genesis of its creation, description of the current situation and determination of the development opportunities. As part of the aim, programs supporting the development of solar energy in Poland have been described and the SWOT analysis has also been performed. The strengths of photovoltaics include high social acceptance and low costs of photovoltaics system operation, while opportunities include rapidly increasing technological efficiency and decreasing cost of solar systems. On the other hand, weaknesses include the high costs of photovoltaics systems and the disparities in the amount of solar energy reaching the market during the year, whereas climate change and the coronavirus pandemic are threats. In 2020, PV became an investment hit in the energy sector and an economic driver in Poland. In the difficult time of two lockdowns caused by the global pandemic, domestic PV made a significant contribution to the maintenance of investment processes in the amount of PLN 9.5 billion and provided Poland with 35 thousand jobs. In 2020, 1.5% of the country’s electricity came from PV sources. In 2021, it will be 3.5%, and by 2025, solar energy will provide approx. 10% of Poland’s electricity. It is worth examining the development of photovoltaics from a broad and long-term perspective. The spectacular development of photovoltaics in Poland is due to hitting the right time window and reducing technology costs, but most of all, it is based on the cooperation of stakeholders and trust in the regulatory environment.
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The Challenge of Quantification: An Interdisciplinary Reading
- Marta Kuc-Czarnecka
- Monica Di Fiore
- Samuele Lo Piano
- Arnald Puy,
- Andrea Saltelli,
The present work looks at what we call “the multiverse of quantification”, where visible and invisible numbers permeate all aspects and venues of life. We review the contributions of different authors who focus on the roles of quantification in society, with the aim of capturing different and sometimes separate voices. Several scholars, including economists, jurists, philosophers, sociologists, communication and data scientists, express concerns or identify critical areas of our relationship with new technologies of ‘numericization’. While mindful of the important specificities of the different families of quantification, we use our broad and holis- tic canvas to explore possible spaces for a more systematic investigation of incumbent and novel quantifications, as to increase communication among disciplinary communities, and among these and society, in the pursuit a democratic agency and self-defence.
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The characterization of collagen‑based scaffolds modified with phenolic acids for tissue engineering application
- Beata Kaczmarek-Szczepańska
- Izabela Polkowska
- Marcin Małek
- Janusz Kluczyński
- Katarzyna Paździor-Czapula
- Marcin Wekwejt
- Michno Anna
- Anna Ronowska
- Anna Pałubicka
- Beata Nowicka
- Iwona Otrocka-Domagała
The aim of the experiment was to study the morphology of collagen-based scaffolds modified by caffeic acid, ferulic acid, and gallic acid, their swelling, and degradation rate, as well as the biological properties of scaffolds, such as antioxidant activity, hemo- and cytocompatibility, histological observation, and antibacterial properties. Scaffolds based on collagen with phenolic acid showed higher swelling rate and enzymatic stability compared to scaffolds based on pure collagen, and the radical scavenging activity was in the range 85–91%. All scaffolds were non-hemolytic and compatible with surrounding tissues. Collagen modified by ferulic acid showed potentially negative effects on hFOB cells as a significantly increased LDH release was found, but all of the studied materials had antimicrobial activity against Staphylococcus aureus and Escherichia coli. It may be assumed that phenolic acids, such as caffeic, ferulic, and gallic acid, are modifiers and provide novel biological properties of collagen-based scaffolds. This paper provides the summarization and comparison of the biological properties of scaffolds based on collagen modified with three different phenolic acids.
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The coexistence and competition of canonical and comammox nitrite oxidizing bacteria in a nitrifying activated sludge system – Experimental observations and simulation studies
- Jacek Mąkinia
- Mohamad-Javad Mehrani
- Przemysław Kowal
- Dominika Sobotka
- Martyna Godzieba
- Sławomir Ciesielski
- Jianhua Guo
The second step of nitrification can be mediated by nitrite oxidizing bacteria (NOB), i.e. Nitrospira and Nitrobacter, with different characteristics in terms of the r/K theory. In this study, an activated sludge model was developed to account for competition between two groups of canonical NOB and comammox bacteria. Heterotrophic denitrification on soluble microbial products was also incorporated into the model. Four 5-week washout trials were carried out at dissolved oxygen-limited conditions for different temperatures (12℃ vs. 20℃) and main substrates (NH4+-N vs. NO2--N). Due to the aggressive reduction of solids retention time (from 4 to 1 d), the biomass concentrations were continuously decreased and stabilized after two weeks at a level below 400 mg/L. The collected experimental data (N species, biomass concentrations, and microbiological analyses) were used for model calibration and validation. In addition to the standard predictions (N species and biomass), the newly developed model also accurately predicted two microbiological indicators, including the relative abundance of comammox bacteria as well as nitrifiers to heterotrophs ratio. Sankey diagrams revealed that the relative contributions of specific microbial groups to N conversion pathways were significantly shifted during the trial. The contribution of comammox did not exceed 5% in the experiments with both NH4+-N and NO2--N substrates. This study contributes to a better understanding of the novel autotrophic N removal processes (e.g. deammonification) with nitrite as a central intermediate product.
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The comparison of antioxidant properties and nutrigenomic redox-related activities of vitamin C, C-vitamers, and other common ascorbic acid derivatives
- Patrycja Jakubek
- Klaudia Suliborska
- Monika Kuczyńska
- Muhammad Asaduzzamana
- Karol Parchem
- Izabela Koss-Mikołajczyk
- Barbara Kusznierewicz
- Wojciech Chrzanowski
- Jacek Namieśnik
- Agnieszka Bartoszek-Pączkowska
The term ‘vitamin C’ describes a group of compounds with antiscorbutic activity of L-ascorbic acid (AA). Despite AA’s omnipresence in plant-derived foods, its derivatives have also been successfully implemented in the food industry as antioxidants, including the D-isomers, which lack vitamin C activity. This study aimed to determine the relationship between redox-related activities for five derivatives of AA using electrochemical, chemical, and biological approaches. Here we report that AA, C-vitamers, and other commonly consumed AA derivatives differ in their redox-related activities. As long as the physiological range of concentrations was maintained, there was no simple relationship between their redox properties and biological activity. Clear distinctions in antioxidant activity were observed mostly at high concentrations, which were strongly correlated with electrochemical and kinetic parameters describing redox-related properties of the studied compounds. Despite obvious similarities in chemical structures and antioxidant activity, we showed that C-vitamers may exhibit different nutrigenomic effects. Together, our findings provide a deeper insight into so far underinvestigated area combining chemical properties with biological activities of commonly applied AA derivatives.
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The complexity of bicriteria tree-depth
- Piotr Borowiecki
- Dariusz Dereniowski
- Dorota Osula
The tree-depth problem can be seen as finding an elimination tree of minimum height for a given input graph G. We introduce a bicriteria generalization in which additionally the width of the elimination tree needs to be bounded by some input integer b. We are interested in the case when G is the line graph of a tree, proving that the problem is NP-hard and obtaining a polynomial-time additive 2b-approximation algorithm. This particular class of graphs received significant attention in the past, mainly due to a number of potential applications, e.g.in parallel assembly of modular products, or parallel query processing in relational databases, as well as purely combinatorial applications including searching in tree-like partial orders (which in turn generalizes binary search on sorted data).
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The congruence of mental models in entrepreneurial teams – implications for performance and satisfaction in teams operating in an emerging economy
- Paweł Ziemiański
- Katarzyna Stankiewicz
- Michał Tomczak
- Beata Krawczyk-Bryłka
Purpose – The paper aims to explore the relationship between the congruence of mental models held by the members of entrepreneurial teams operating in an emerging economy (Poland) and entrepreneurial outcomes (performance and satisfaction). Design/methodology/approach – The data obtained from 18 nascent and 20 established entrepreneurial teams was analysed to answer hypotheses. The research was quantitative and was conducted using an online questionnaire. Data was collected from each of the teams at two stages. Members of entrepreneurial teams were surveyed independently, which allowedmeasuring the congruence of their mental models pertaining to running a venture. Findings – Findings reveal that team members’ mental model congruence is significantly related to financial performance and members’ satisfaction in the case of established entrepreneurial teams. However, in the case of nascent teams, there is no relationship between analysed variables. Practical implications – Implications for theory and practice are offered with a special emphasis on entrepreneurship education. The concept of team mental model congruence is proposed to be included in training of nascent entrepreneurial teams, experienced companies and students. Originality/value – The concept of team mental models investigated by the authors has been underexplored in entrepreneurship research. Results indicate that at least in some entrepreneurial teams, team mental models’ congruence is related to obtained outcomes. The paper proposes that principles of effectuation and causation can serve as the lens through which the mental model pertaining to running a venture can be analysed. It allows expanding studies on the congruence of team mental models in entrepreneurial teams beyond the strategic consensus.
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The correlation between nutritional and health potential and antioxidant properties of raw edible oils from cultivated and wild plants
- Dorota Martysiak-Żurowska
- Małgorzata Orzołek
The nutritional properties and health potential of oils from 15 various cultivated and wild plants were investigated on the basis of the fatty acids profiles, total carotenoids and tocopherols content, antioxidant properties and health potential indexes such as atherogenicity index (AI). The oil contents of the plants varied between 0.9 g/100 g for lychee seeds and 29.7 g/100 g for borage seeds. The tocopherol content in oils ranged from 0.31 (lingonberry fruits) to 226.23 mg/100 g (hawthorn pulp), carotenoids ranged from 0.36 (borage seeds) to 14.22 mg/100 g (blackcurrant seeds). In four oils (raspberry seed, strawberry seed, lingonberry fruits, blackcurrant seeds) the PUFA contents contributed over 70% of the total fatty acids (FA), which was associated with the best values health potential indexes. It was found that TAC (Total Antioxidant Capacity) can be an indirect measure of the levels of carotenoids and tocopherols in oils. Additionally, a positive correlation between the level of carotenoids and the FA n-3 was demonstrated. Determining such relationships may facilitate research into new sources of valuable edible oils useful for the production of functional foods, dietary supplements and cosmetics.
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The correlation of fractal dimension to fracture surface slope for fatigue crack initiation analysis under bending-torsion loading in high-strength steels
- Wojciech Macek
- Ricardo Branco
- Przemysław Podulka
- Reza Masoudi Nejad
- José Domingos Costa
- J. A. M. Ferreira
- C. Capela
In this study, the fractal dimension of fatigue fracture surfaces is investigated in order to find an alternative failure loading indicator. Some of many metrological factors are generalized by reducing the fracture surface structure to one factor and develop an entire fracture surface procedure by analyzing the impact of surface slope and calculation resolution. Three notched geometries are studied under cyclic bending-torsion: 34CrNiMo6 high-strength steel bars with transverse blind holes; (ii) 34CrNiMo6 high-strength steel bars with lateral U-shaped notches; and (iii) 18Ni300 maraging steel hollow bars with transverse holes produced by selective laser melting. The surface topographies of fatigue fractures were measured with an optical profilometer. The bending-torsion ratio, maximum local von Mises equivalent stress and the number of cycles to crack initiation are examined using the fractal dimension. Moreover, a comparison was also made for conventional surface topography parameters such as root mean square height and void volume. A fatigue crack initiation model based on surface topography and loading conditions is proposed. The model relies on the product of the maximum local von Mises equivalent stress and the fractal dimension divided by the root mean square height to void volume ratio. The results show that the fracture plane geometry, expressed by the fractal dimension Df, can facilitate the estimation of post-failure loading history. In particular, the analysis based on the enclosing boxes method (EBM) is more accurate when it is used as an extra-fine resolution without any plane leveling.
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The Cultures of Knowledge Organizations: Knowledge, Learning, Collaboration (KLC)
- Wioleta Kucharska
- Denise A. D. Bedford
This book focuses on seeing, understanding, and learning to shape an organization’s essential cultures. The book is grounded on a fundamental assumption that every organization has a de facto culture. These “de facto cultures” appear at first glance to be serendipitous, vague, invisible, and unmanaged. An invisible and unrecognized de facto culture can undermine business goals and strategies and lead to business failures. The authors believe that humans can learn to “see” culture around them and understand their influence on individuals, teams, organizations, and societies. At its core, the book lays out the levels of culture to help the reader “see” and learn how to shape a knowledge organization’s cultures. Learning to see and understand the culture, mainly organizational culture, is critical in today’s hyperdynamic knowledge economy. Culture will always dominate strategy in any economy. However, it can play an even more significant role in the knowledge economy, where knowledge is the primary form of capital and the most critical production factor. To thrive and survive in the knowledge economy, managers must “see” their company culture’s power to shape the company’s course and learn to gain and sustain knowledge, learning, and collaboration (KLC) cultures synergy. Hyperdynamic business reality requires smart actions. When managers “see” their cultures as an asset, they have an opportunity to shape those cultures and use them for the company’s best.
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The dependence of linear viscoelasticity limits of cold-recycled mixtures on time of curing and compaction method
- Mariusz Jaczewski
- Cezary Szydłowski
- Bohdan Dołżycki
Cold-recycled mixtures are currently among the most widely used and investigated methods that enable recycling of old pavement structures in an environmentally friendly manner. Upon milling, the old pavement structure – whose gradation can be improved with addition of virgin aggregate – is mixed and compacted at ambient temperature. The main binding agents are bituminous emulsion and cement. Due to their dual binding behaviour, cold-recycled mixtures present various problems and challenges in terms of correct testing. One of such challenges is the testing of stiffness modulus of cold-recycled mixtures. Apart from dependence of modulus on test temperature and time of curing, recent research proved its highly nonlinear behaviour, much wider than that of classical asphalt mixtures. The paper presents the results of research of linear viscoelasticity limits based on testing conducted in Simple Performance Tester (SPT) device for one cold-recycled mixture recipe, using samples prepared and compacted in different manner. One mixture was prepared in laboratory conditions from materials obtained from the field section. Second mixture was prepared on the basis of field-mixed materials (material prepared and mixed in field, compacted in laboratory). Additionally, cores obtained from the field at 28 and 180 days after compaction were tested. All mixtures were tested at the temperature of 20 C. Tests were performed 7, 14, 28, 42, 90 and 180 days after compaction. The controlled strain mode was chosen, with strain ranging from 20 to 200 lstrain. Stiffness modulus and phase angle were measured. The test showed that the linear viscoelasticity limits for stiffness modulus testing changed with the time that had elapsed since the compaction for all specimens – the initially low values (of 45–55 lstrain) increased with time and reached constant values (of 75–95 lstrain), with different levels depending on the specimen preparation method.
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The Design of Cavity Resonators and Microwave Filters Applying Shape Deformation Techniques
- Michał Baranowski
- Łukasz Balewski
- Adam Lamęcki
- Michał Mrozowski
- Jaione Galdeano
This article introduces shape deformation as a new approach to the computer-aided design (CAD) of high-frequency components. We show that geometry deformation opens up new design possibilities and offers additional degrees of freedom in the 3-D modeling of microwave structures. Such design flexibility is highly desirable if the full potential of additive manufacturing (AM) is to be exploited in the fabrication of RF and microwave devices. The use of deformation techniques in the design of high-frequency components allows the attainment of improved electrical parameters, such as high-quality factors for cavity resonators and wide higher-order mode separation. In this work, shape deformation with radial basis functions (RBFs) is integrated with an electromagnetic field simulator based on the 3-D finite-element method (FEM), allowing the semiautomated optimization of microwave components, such as cavity resonators and filters. The proposed strategy is used for the design of high Q-factor cavity resonators, cavity bandpass filters with improved spurious mode separation, and a compact twisted waveguide filter. Three designs of waveguide cavity filters with complex geometry are experimentally verified using 3-D-printed prototypes fabricated with selective laser melting (SLM) technology
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The Double Cognitive Bias of Mistakes: A Measurement Method
- Wioleta Kucharska
- Denise A. D. Bedford
- Aleksandra Kopytko
There is no learning without mistakes. However, making mistakes among knowledge workers is s�ll seeing shameful. There is a clash between posi�ve a�tudes and beliefs regarding the power of gaining new (tacit) knowledge by ac�ng in new contexts and nega�ve a�tudes and beliefs toward accompanying mistakes that are sources of learning. These contradictory a�tudes create a bias that is doubled by the other shared solid belief that “BOSSES NEVER MAKE MISTAKES.” The double cogni�ve bias of mistakes introduced by Kucharska and Bedford (2023) is assumed in this paper to harm organiza�onal learning and collec�ve intelligence development. To jus�fy this point empirically in this paper, the authors propose a procedure enabling the measurement of the double cogni�ve bias of mistakes. Moreover, to validate the proposed method, authors empirically examine the influence of the KLC cultures’ synergy on knowledge sharing and organiza�onal intelligence and compare obtained results with the effect observed for the sample free of the double bias of mistakes. Novelty: this studyis the first to propose iden�fying the double bias of mistakes and empirically exposing its impacts.
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The Effect of C45 Carbon Black-Phosphomolybdic Acid Nanocomposite on Hydrogenation and Corrosion Resistance of La2Ni9Co Hydrogen Storage Alloy
- Krystyna Giza
- Edyta Owczarek
- Andrzej Miszczyk
In this paper, we analysed the influence of corrosion processes and the addition of a carbon black-heteropoly phosphomolybdic acid (C45-MPA) nanocomposite on the operating parameters of a hydride electrode obtained on the basis of the intermetallic compound La2Ni9Co. The electrochemical properties of negative electrodes for NiMH batteries were studied using galvanostatic charge/discharge curves, the potentiostatic method, and electrochemical impedance spectroscopy (EIS). The morphology and chemical composition analysis of the studied electrodes were investigated by means of scanning electron microscopy (SEM) with supporting energy-dispersive X-ray analysis (EDS). For more structural information, FTIR analysis was performed. The results indicate that the presence of the C45-MPA nanocomposite in the electrode material increased both the discharge capacity of the hydride electrode and the exchange current density of the H2O/H2 system. The heteropoly acid-modified electrode is also more resistant to high discharge current densities due to its catalytic activity.
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The effect of hybridization of fire retarded epoxy/flax-cotton fiber laminates by expanded vermiculite: Structure-property relationship study
- Mateusz Barczewski
- Kamila Sałasińska
- Wojciech Raś
- Aleksander Hejna
- Sławomir Michałowski
- Paulina Kosmela
- Joanna Aniśko
- Anna Boczkowska
- Marek Szostak
The study describes the hybridization of epoxy/flax-cotton (EP/FF) composites containing ammonium polyphosphate (APP) with micrometric expanded vermiculite (VMT) (1–10 wt%). The efficiency of hybridization of flame retarded epoxy/flax-cotton composites was assessed by performing static tensile and flexural strength evaluation, supplemented by impact strength measurements of the composites. Moreover, thermal and thermomechanical analyses (DMA, DSC, and TGA) were performed. Epoxy composites were subjected to flammability using a PCFC microcalorimeter and cone calorimeter measurement to assess the burning behavior of composites. The introduction of the low-cost plate-shaped filler resulted in several favorable thermal effects while deteriorating the structure of the composite. The addition of small amounts of vermiculite (1–2 wt%) into the matrix modified with APP enabled the reduction of heat release rate (HRR) and total heat release (THR) by 60% and 20%, respectively. The comprehensive structure-properties analysis determined the critical filler contents, yielding synergistic flame-retardant effects with a limited negative impact on the composites' performance.
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The effect of impacted third molars on second molar external root resorption, a cross-sectional cone beam computed tomography study
- G. Gürses
- A. Akçakaya
- A. Aktı
- Olgun Aydin
Background: Third molars have the highest prevalence of impaction in teeth and can cause pathological damage on the adjacent second molars. This study aims to evaluate the effects of factors related to impacted third molars on external root resorption (ERR) in adjacent second molars using cone-beam computed tomography (CBCT). Material and Methods: In CBCTs, the effect of impacted third molars on the root surface of adjacent second molars was investigated. Inclusion criteria for subjects were being older than 16 and younger than 55, presence of at least one impacted third molar and adjacent second molar. Exclusion criteria were pathology, a follicle gap greater than 5 mm, crowned second molar, severe decay, an artifact on a radiologic image, and previous surgery on the second or third molars. The investigations were made based on age range, gender, tooth inclination, Pell-Gregory classification, retention type, contact area, root formation, pericoronal width, and tooth absence on the same quadrant for potential risk factors. The collected data were statistically analyzed with R software. The Chi-Square test was used to find out any significant difference. Logistic regression analyses were done for potential risk factors for ERR. Results: A total of 437 impacted third molars and adjacent second molars were investigated using CBCT. Of these, 381 met the inclusion criteria. Mesioangular and horizontal inclination, Pell-Gregory Class B-C, contact area, and retention type were found the statistically potential risk factors for ERR. Conclusions: The impacted third molar with horizontal or mesioangular position, and osseous retention, with Pell and Gregory Class B and C, are more likely to cause external root resorption in adjacent second molars
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The effect of multiaxial geocomposite reinforcement on fatigue performance and crack propagation delay in double-layered asphalt beams
- Piotr Jaskuła
- Dawid Ryś
- Cezary Szydłowski
- Michał Golos
- K. Kornacka
- Joanna Żółtko
- Jacek Kawalec
- Marcin Stienss
The presented study investigates the effect of a recently developed multiaxial geocomposite made of polypropylene geogrid and non-woven fabric on the delay of crack propagation, based on four-point bending tests of large asphalt concrete beams – both for reinforced and non-reinforced specimens. Several approaches are described in this study, including analysis of stiffness modulus decrease and analysis of crack propagation using dissipated energy. The study also includes investigation of the impact of reinforcement on shear resistance of the inter-layer bond. The reinforced system displays reduced decrease in stiffness during cyclic loading; it is able to bear loads over a longer period, in contrast to the unreinforced system. An increase in fatigue life by a factor of 10–22 is possible, as compared to the unreinforced system. The factor of relative increase in the number of cycles to the first initiation of crack in lower asphalt layer when reinforcement is introduced ranges from 5 to 10.
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The effect of PEDOT morphology on hexavalent chromium reduction over 2D TiO2/PEDOT photocatalyst under UV–vis light
- Agnieszka Sulowska
- Agnieszka Fiszka Borzyszkowska
- Karolina Cysewska
- Katarzyna Siwińska-Ciesielczyk
- Konstantin Nikiforow
- Grzegorz Trykowski
- Anna Zielińska-Jurek
The present study represents an approach to apply organic-inorganic hybrid materials for photocatalytic removal of heavy metals from the aqueous environment. The photocatalytic activity of the semiconductor modified with the conjugated polymer may depends on the conjugated polymer type, its amount and morphology. Therefore, in the present study the effect of poly (3, 4-ethylenedioxythiophene) (PEDOT) morphology on adsorption and photoreduction of Cr(VI) to Cr(III) under simulated solar light (UV–vis) and vis light (λ > 400 nm) was investigated. The composite of titanium (IV) oxide and PEDOT of different morphology was obtained using the waterin- oil microemulsion method. The obtained hybrid photocatalysts were characterized by diffuse reflectance spectroscopy (DR/UV–vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM, TEM), specific surface area (BET) and X-ray photoelectron spectroscopy (XPS) analyzes. PEDOT and its composites with TiO2 nanosheets of anatase were used for the degradation of highly toxic Cr(VI) under the simulated solar light. The 2D TiO2/PEDOT composite with PEDOT microvesicular morphology reveals the highest efficiency of Cr(VI) photoreduction to Cr(III). The synergistic
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The effect of sunscreen 4‐methylbenzylidene camphor in different and reproductive models, its bioaccumulation and molecular effects on ligand‐receptor interaction, and protein expression
- Cassandra Lax
- Elin Wicksell
- Anastasia Grip
- Jenni Viivi Linnea Niemi
- Wen Liu
- Alexandra Rafeletou
- Błażej Kudłak
- Helgi B. Schiöth
4-Methylbenzylidene camphor (4-MBC) is a photo-absorbing UV filter prevalently used in cosmetics, which can be absorbed into circulation and cause systemic effects. 4-MBC is continued to be released in the environment despite the growing knowledge about its bioaccumulation and endocrine disrupting effects. Previous reviews have mentioned UV-filter together but this review considers 4-MBC alone, due to its prevalence and concerning health effects. This review considers 4-MBC’s potential effects on human health regarding systemic and molecular effects, with the main focus on reproduction. Also, the potential bioaccumulation and interactions with receptor systems such as the oestrogen receptors β and α, and progesterone receptor are covered. Additionally, previous studies about 4-MBC’s effects on mRNA and protein expression, especially in the prostate and the brain are analysed. Furthermore, 4-MBC is reported to act with inflammatory pathways by activating p38 MAPK and NF-κB, leading to the production of inflammatory TNF-α and IL-6. 4-MBC was also found to induce apoptosis and inhibit cell proliferation and DNA repair. In conclusion, 4-MBC has wide-ranging effects in many different models interacting with multiple pathways causing long-term effects even at low doses and this knowledge can guide governmental risk assessment, regulation divisions and chemical industries.
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The effect of thermal modification on the quality of the milled surface of beech and pine wood
- Richard Kminiak
- Lukas Adamčík
- Daniel Chuchała
The article deals with the effect of thermal modification on the quality of the created surface during milling on CNC milling cutters. The quality of the created surface is evaluated based on surface roughness, specifically its roughness parameter Ra. The observed surface is created by a shank cutter with a diameter of 20 mm and three cutting edges in a spiral at a standard speed of 18,000. min-1. The article compares thermally modified pine wood and beech wood of at temperatures of 160, 180, 200 and 220°C with a reference sample of kiln dried wood of the given wood species. The article also monitors the variability of the quality of the created surface due to the change in the feed speed of 2, 4 and 6 m·min-1 and the thickness of removal of 1, 3 and 5 mm within the given degree of thermal modification. The article points to the fact that the average value of the arithmetic mean height (Ra) is below 10 μm for both types of wood, regardless of the degree of thermal modification. This meets the general requirements for the surface quality of furniture blanks. The mutual comparison of wood species showed that beech wood forms an average of 1.5 μm higher quality surface than wood pine. Thermal modification within both studied wood species improves the quality indicators of the created surface. In terms of the effect of specific temperatures, the highest quality of the created surface is at 180°C and deteriorates in the range of 180, 200, 160, 220°C. From the point of view of the influence of the investigated technological factors, no statistically significant influence of either the feed speed or the thickness of removed layer was demonstrated.