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Publications from the year 2020
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Spectroscopic Optical Coherence Tomography for Thin Layer and Foil Measurements
- Aleksandra Kamińska
- Marcin Strąkowski
- Jerzy Pluciński
The main goal of this research was to assess if it is possible to evaluate the thickness of thin layers (both thin films on the surface and thin layers below the surface of the tested object) and foils using optical coherence tomography (OCT) for thickness assessment under the resolution of the standard commercially available OCT measurement system. In the proposed solution, light backscattered from the evaluated thin layer has been expressed as a multiple beam interference. Therefore, the OCT system was modeled as a two-beam interferometer (e.g., Michelson), in which one beam propagates from the reference arm and the other comes from a Fabry–Pérot interferometer. As a consequence, the mathematical model consists of the main Michelson interferometer, in which the measuring arm represents the Fabry–Pérot interferometer. The parameters of the layer (or foil) are evaluated by analyzing the minimum value of the interference contrast. The model developed predicts the behavior of the thin layers made from different materials (with different refractive indexes) with different thickness and located at different depths. To verify the correctness of the proposed model, an experiment with a wedge cell has been carried out. The wedge cell was shifted across the scanning beam using a linear translation stage with a micrometer screw under the scanning head. The relationship between the thickness of the gap of the wedge cell and the OCT output signal is presented. For the additional verification of the proposed model, the results of the measurements of the thickness of the thin foil were compared with the theoretical results of the simulations. The film thickness was evaluated based on the calculated positions of the minimum value of interference contrast. A combination of the standard potentialities of OCT with the proposed approach to analyzing the signal produces new metrological possibilities. The method developed allows us to evaluate thickness under the resolution of the system and the location of the layer as well. This produces the possibility of measuring a layer which is covered by another layer. Moreover, it is possible to create a thickness map with high sensitivity to thickness changes. These experiments and simulations are the culmination of preliminary research for evaluating the potential of the proposed measurement method.
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Spectroscopic studies of Nb-doped tricalcium phosphate glass-ceramics prepared by sol-gel method
- Wojciech Korzeniewski
- Agnieszka Witkowska
- Maciej Manecki
Calcium-phosphate based glasses and glass-ceramics play a crucial role in the tissue engineering development. Apart from their high biocompatibility and excellent ability to undergo varying degrees of resorbability1, they exhibit relatively high bioactivity and due to that they are commonly used as bone and dental implants. A substantial research effort is devoted to improve calcium-phosphate materials physico-chemical properties by tuning their degree of crystallinity and doping them with metal ions is one of the mostly researched strategies. The results found in the literature show that synthesized CaOP2O5-Nb2O5 compounds exhibit a good biocompatibility, very low cytotoxicity in respect to calciumphosphate doped with other metals and additionally can enhance human osteoblast function2,3. As of today structure of these materials is not thoroughly described. Therefore, the detailed structural investigation by means of spectroscopic studies, i.e. FTIR spectroscopy, Raman spectroscopy, XAFS spectroscopy, XPS and EDX, together with SEM imaging, XRD and BET surface area measurements, was realized to shed light on the relationship between materials structure and the presence of dopant. In this work, we show the results obtained for bioactive glass-ceramics, prepared via simple sol-gel method, with Ca/(P+Nb) molar ratio equal to 1.5 and with relative Nb contents of 0 mol% and 10 mol% of P. XRD patterns analysis shows that samples consist of tricalcium phosphate and hydroxyapatite phase. Raman spectra analysis confirms the incorporation of Nb into the material structure. Moreover, niobium doping leads to an increase in degree of crystallinity and crystallite size of the sample. Stoichiometry of the ceramics is as intended. Additionally, there is a greater proportion of carbonate groups in the doped material than in the undoped one (FTIR, Raman spectroscopy), and all samples exhibit calcium deficiency on the surface (XPS). XAFS analysis shows presence of octahedral coordination of niobium ions, with average oxidation state around +4.5 and XPS analysis indicates that on the sample surface the contribution of Nb+5 ions is greater than Nb+4 ions. Additionally it can be concluded, that Nb accumulates on materials surface.
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Spinon excitations in the quasi-one-dimensional S=12 chain compound Cs4CuSb2Cl12
- Thao Tran
- Chris A. Pocs
- Yubo Zhang
- Michał Winiarski
- Jianwei Sun
- Minhyea Lee
- Tyrel McQueen
The spin−1/2 Heisenberg antiferromagnetic chain is ideal for realizing one of the simplest gapless quantum spin liquids (QSLs), supporting a many-body ground state whose elementary excitations are fractional fermionic excitations called spinons. Here we report the discovery of such a one-dimensional (1D) QSL in Cs4CuSb2Cl12. Compared to previously reported S=1/2 1D chains, this material possesses a wider temperature range over which the QSL state is stabilized. We identify spinon excitations extending at T>0.8K, with a large T-linear contribution to the specific heat, γ=31.5(2)mJmol−1K−2, which contribute itinerantly to thermal transport up to temperatures as high as T=35K. At T=0.7K, we find a second-order phase transition that is unchanged by a μ0H=5T magnetic field. Cs4CuSb2Cl12 reveals new phenomenology deep in the 1D QSL regime, supporting a gapped QSL phase over a wide temperature range compared to many other experimental realizations.
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Spirala 2 (wg Ulama) z cyklu No Quick Response
- Krzysztof Wróblewski
Spirala 2 (wg Stanisława Ulama) Obraz odnosi się do modelu matematycznego nazywanego Spiralą Ulama, który polega na okrężnym zapisie w polu kwadratu liczb naturalnych od 1 do nieskończoności. Taki zapis uwidacznia szczególne wzory, które powstają z położenia liczb pierwszych (niepodzielnych). Liczby pierwsze tworzą ciągi mniej lub bardziej regularne w układzie diagonalnym, poziomym i pionowym. W obrazie Spirala 2 wykorzystany został zestaw liczb od 1 do 1600. Położenia liczb pierwszych są malowane czernią i bielą, natomiast położenie pozostałych liczb kolorami podstawowymi i pochodnymi w różnej tonacji. Kolory "wędrują" progresywnie za liczbami po kształcie spirali. Sekwencyjny rytm przerywany jest położeniem liczby pierwszej. W wyniku tego zabiegu samorzutnie powstają grupy różnych form i kolorów, przy czym żadna z nich nie jest dominująca w całości układu. Poszczególne kształty są tylko cząstkami większej całości. W spirali Ulama podobnie jak w ciągu Fibonacciego występuje rodzaj harmonijnej jedności. Krzysztof Wróblewski
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Społeczna odpowiedzialność biznesu w branży odzieżowej - perspektywa polskiego konsumenta
- Ewa Marjańska
- Piotr Grudowski
- Anna Wendt
- Mateusz Muchlado
Przesunięcie produkcji do krajów dotkniętych ubóstwem towarzyszy podejściu kładącemu nacisk na szybkie odpowiedzialność i tanie udostępnianie trendów modowych konsumentom oraz systemowi wytwarzania opartemu na popycie biznesu, w przemyśle odzieżowym. W artykule zwrócono uwagę na: świadomość, postawy, zachowania etyczne oraz zrównoważony sposób postrzegania jakości produktów „fast fashion” w perspektywie społecznej odpowiedzialności. Na rozwój, podstawie metody CAWI i PAPI przeprowadzono badanie polskich konsumentów deklarujących zachowania przemysł odzieżowy, nabywcze związane z „fast fashion”. Badania wykazały, że działania związane ze społeczną odpowiedzialnością fast fashion biznesu w branży odzieżowej są istotne dla klientów, jednak cena jest najważniejszym czynnikiem przy podejmowaniu decyzji o zakupie. Ocena świadomości konsumentów w zakresie CSR może posłużyć do ukierunkowania przyszłych działań edukacyjnych w tym obszarze, zwłaszcza w dobie przyspieszonej konsumpcji i celów zrównoważonego rozwoju. Wyniki badań mogą też być przesłanką do określenia kierunku działań związanych z CSR dla sprzedawców „fast fashion”.
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Społeczna odpowiedzialność biznesu w kontekście strategii wybranych spółek posiadających istotne znaczenie dla gospodarki
- Sebastian Skuza
- Anna Modzelewska
- Malwina Popiołek
- Marta Szeluga-Romańska
Przedmiotem badań jest analiza sposobów realizacji strategii społecznej odpowiedzialności biznesu przez przez wybrane spółki z udziałem Skarbu Państwa.
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Stability analysis of interconnected discrete-time fractional-order LTI state-space systems
- Łukasz Grzymkowski
- Damian Trofimowicz
- Tomasz Stefański
In this paper, a stability analysis of interconnected discrete-time fractional-order (FO) linear time-invariant (LTI) state-space systems is presented. A new system is formed by interconnecting given FO systems using cascade, feedback, parallel interconnections. The stability requirement for such a system is that all zeros of a non-polynomial characteristic equation must be within the unit circle on the complex z-plane. The obtained theoretical results lead to a numerical test for stability evaluation of interconnected FO systems. It is based on modern root-finding techniques on the complex plane employing triangulation of the unit circle and Cauchy’s argument principle. The developed numerical test is simple, intuitive and can be applied to a variety of systems. Furthermore, because it evaluates the function related to the characteristic equation on the complex plane, it does not require computation of state-matrix eigenvalues. The obtained numerical results confirm the efficiency of the developed test for the stability analysis of interconnected discrete-time FO LTI state-space systems.
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Stability analysis of nanobeams in hygrothermal environment based on a nonlocal strain gradient Timoshenko beam model under nonlinear thermal field
- Subrat Kumar Jena
- S. Chakraverty
- Mohammad Malikan
This article is dedicated to analyzing the buckling behavior of nanobeam subjected to hygrothermal environments based on the principle of the Timoshenko beam theory. The hygroscopic environment has been considered as a linear stress field model, while the thermal environment is assumed to be a nonlinear stress field based on the Murnaghan model. The size-dependent effect of the nanobeam is captured by the nonlocal strain gradient theory (NSGT), and the governing equations of the proposed model have been derived by implementing a variational principle. The critical buckling loads have been calculated for the hinged–hinged boundary condition by incorporating the Navier approach and considering other elasticity theories such as classical elasticity theory, Eringen nonlocal elasticity theory, and strain gradient theory along with the NSGT. The present model is also validated with the pre-existing model in exceptional cases. Further, a parametric investigation has been performed to report the influence of various scaling parameters like hygroscopic environment, thermal environment, length-to-diameter ratio, small scale parameter, and length scale parameter on critical buckling loads by considering both the linear and nonlinear temperature distributions.
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Stabilizing lactate production through repeated batch fermentation of food waste and waste activated sludge
- Xianbao Xu
- Wenjuan Zhang
- Xia Gu
- Zhichao Guo
- Jian Song
- Daan Zhu
- Yanbiao Liu
- Yanan Liu
- Gang Xue
- Xiang Li
- Jacek Mąkinia
Bio-valorization of organic waste streams, such as food waste and waste activated sludge, to lactic acid (LA) has recently drawn much attention. It offers an opportunity for resource recovery, alleviates environmental issues and potentially turns a profit. In this study, both stable and high LA yield (0.72 ± 0.15 g/g total chemical oxygen demand) and productivity rate (0.53 g/L•h) were obtained through repeated batch fermentation. Moreover, stable solubilization and increase in the critical hydrolase activities were achieved. Depletions of ammonia and phosphorus were correlated with the LA production. The relative abundance of the key LA bacteria genera (i.e., Alkaliphilus, Dysgonomonas, Enterococcus and Bifidobacterium) stabilized in the repeated batch reactor at a higher level (44.5 ± 2.53%) in comparison with the batch reactor (26.2 ± 4.74%). This work show a practical way for the sustainable valorization of organic wastes to LA by applying the repeated batch mode during biological treatment.
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Standardy Profesjonalnego Public Relations
- Jacek Barlik
- Ewa Hope
- Jerzy Olędzki
- Krystyna Wojcik
" Standardy przedstawiają wartości i pryncypia uzasadniające konieczność dokonywania odpowiednich wyborów. Public relations ma godzić interesy zleceniodawców, przedstawicieli mediów i różnych grup społeczeństwa, a przy tym pozostawać w zgodzie z normami etycznymi i odwoływać się do takich wartości jak szacunek, godność, rzetelność, uczciwość, prawda, wiarygodność, niezależność, lojalność i zaufanie. Opracowanie "Standardów profesjonalnego Public Relations" zostało przygotowane przez społeczny zespół ekspertów - autorzy dokumentu, w przekonaniu, że profesjonalizm i etyka są ze sobą nierozerwalnie połączone -zwłaszcza w dziedzinach, które - jak PR, wpływają na kondycję społeczeństwa."
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Stanowisko laboratoryjne do badania procesów wibroakustycznych w rejonie głowicy cylindrowej silnika z zapłonem samoczynnym - wyniki badań pilotażowych
- Jacek Rudnicki
W artykule przedstawiono założenia oraz ich praktyczną realizację w odniesieniu do stanowiska laboratoryjnego przeznaczonego do badania procesów wibroakustycznych w rejonie głowicy silnika z zapłonem samoczynnym. Podstawowym założeniem podczas realizacji tego projektu było stworzenie możliwości dydaktycznych oraz naukowo – badawczych w zakresie obserwacji i rejestracji procesów drganiowych w rejonie głowicy cylindrowej silnika z zapłonem samoczynnym podczas pracy układu rozrządu napędzane go ze źródła zewnętrznego. Umożliwia to wyselekcjonowanie prawie „czystej” postaci tych procesów, pochodzących wyłącznie od pracy układu rozrządu bez zakłóceń spowodowanych pracą innych przekładni i mechanizmów w rzeczywistym silniku oraz zjawisk gazodynamicznych związanych ze spalaniem. Fakt ten pozwala na rejestrację wartości wybranych wskaźników opisujących drgania tego węzła konstrukcyjnego silnika, odpowiednie opracowanie powstałych zapisów i ich ewentualne wykorzystanie we wnioskowaniu diagnostycznym np. w zakresie oceny faz rozrządu. Innym sposobem wykorzystania tak uzyskanych wyników jest możliwość wykorzystania tych zapisów do filtracji wyników uzyskanych na obiekcie rzeczywistym czyli funkcjonującym silniku.
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Stanowisko wizualizacji zdarzeń w systemie STRADAR – realizacja i funkcje dla operatora
- Bartosz Czaplewski
- Sylwester Kaczmarek
- Jacek Litka
It is crucial for the Border Guard to be equipped with a communication-teleinformatic infrastructure designed to support them in efficient realization of their operational tasks. STRADAR – a system which results are presented in this paper – is such an infrastructure. It is a distributed solution for the maritime division of the border guard. The system, with the use of a network of sensors located in both stationary and mobile points collects, archives and processes information and multimedia data, which can be made available to the staff on their demand. STRADAR consists of a number of functional elements. The paper includes a detailed description of one of them. This element being Event Visualization Post EVP, which utilizes multidisplay set up in the Centrum, to display multimedia presentation of information and data for both archival and current situations.
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Static and Dynamic Mechanical Properties of 3D Printed ABS as a Function of Raster Angle
- Mateusz Galeja
- Aleksander Hejna
- Paulina Kosmela
- Arkadiusz Kulawik
Due to the rapid growth of 3D printing popularity, including fused deposition modeling (FDM), as one of the most common technologies, the proper understanding of the process and influence of its parameters on resulting products is crucial for its development. One of the most crucial parameters of FDM printing is the raster angle and mutual arrangement of the following filament layers. Presented research work aims to evaluate different raster angles (45°, 55°, 55’°, 60° and 90°) on the static, as well as rarely investigated, dynamic mechanical properties of 3D printed acrylonitrile butadiene styrene (ABS) materials. Configuration named 55’° was based on the optimal winding angle in filament-wound pipes, which provides them exceptional mechanical performance and durability. Also in the case of 3D printed samples, it resulted in the best impact strength, comparing to other raster angles, despite relatively weaker tensile performance. Interestingly, all 3D printed samples showed surprisingly high values of impact strength considering their calculated brittleness, which provides new insights into understanding the mechanical performance of 3D printed structures. Simultaneously, it proves that, despite extensive research works related to FDM technology, there is still a lot of investigation required for a proper understanding of this process.
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Step on It Bringing Fullwave Finite-Element Microwave Filter Design up to Speed
- Łukasz Balewski
- Grzegorz Fotyga
- Adam Lamęcki
- Michał Mrozowski
- Martyna Mul
- Piotr Sypek
- Damian Szypulski
There are many steps in the design of a microwave filter: mathematically describing the filter characteristics, representing the circuit as a network of lumped elements or as a coupling matrix, implementing the distributed elements, finding the initial dimensions of the physical structure, and carrying out numerical tuning using electromagnetic (EM) simulators. The whole process is painstaking and time-consuming, and it requires a great deal of engineering expertise. Microwave filters are extremely complex geometric structures, and their simple circuits are often quite hard to represent. Moreover, manufacturing them is costly: to be sure that the hardware resulting from the design will meet the performance goals, rigorous computer tools are used to determine the physical dimensions and evaluate all of the adjustments at the final stage. This last stage is particularly challenging, and advanced computational techniques are required.
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Storage electric multiple units on partially electrified suburban railway lines
- Aleksander Jakubowski
- Natalia Karkosińska-Brzozowska
- Krzysztof Karwowski
- Andrzej Wilk
The paper presents possible environmental, energy and economical gains implied by replacing conventional traction vehicles with independent powered electric multiple units (IPEMU) on partially electrified suburban railways. IPEMUs can operate in two modes of power supply – using overhead catenary or onboard battery storage. Appropriate computer simulations were carried out in the Matlab program, indicating the parameters of storage electric multiple units.
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Strategic Flexibility as a Mediator in Relationship between Managerial Decisions and Organizational Learning: Ambidexterity Perspective
- Monika Stelmaszczyk
- Agata Pierścieniak
Purpose: The purpose of the article is to determine strategic flexibility in the relationship between managerial decisions and organizational learning. The analyses are conducted in the ambidexterity convection. Design/Methodology/Approach: The study was conducted at a textile company. The company is a leader in the textile recycling industry in Poland. Empirical data were collected using the PAPI technique. The survey questionnaire was addressed to all 138 company managers. The response rate was 57%. Linear regression analyses were performed to test the research hypotheses. The significance of indirect effects was checked using the bootstrap method. Findings: Our findings show that as the ambidexterity oriented managerial decisions increases, the organizational learning ambidexterity increases. This relationship mediates strategic flexibility through variable flexibility resources and flexibility coordination. In fact, we have indicated the effect of double mediation. This means that there is a relationship between the independent variable and the dependent variable because of interacting resource flexibility and coordination flexibility. Practical Implications: Our study shows that managerial decisions in the company will become more conducive for improving current ideas and introducing new ideas, including ways of their implementation if the enterprise undertakes the proposed steps. They include the acquisition of resources, to develop practical skills, to care in maintaining relatively low costs and shortening task execution duration, to be able to switch to alternative uses of resources. Originality/Value: The value of our research is gaining new knowledge about strategic flexibility. Arguing its necessity for the existence of relationships between managerial decisions and organizational learning, using the ambidexterity convention, improves the knowledge regarding the identity of this category of flexibility.
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Stratification of nano-pigments in anti-corrosive coatings by means of magnetic field
- Andrzej Miszczyk
- Kazimierz Darowicki
The concept of self-stratification of coatings, although attractive, causes difficulties in its practical use, especially when pigments are added to the resins. An alternative way of obtaining a multilayer structure in a single step was presented. Using the inhomogeneous magnetic field and magnetically active components of the coating, the possibility of vertically graded differentiation of the one layer properties has been verified. For this purpose, the magnetic properties of nickel ferrite (NiFe2O4) nano-particles and magnetic field for their transport in a wet coating were used. It has been shown that it is possible to use the magnetic field to transport magnetic ferrite, used as active anticorrosive pigments, near the coating/substrate interface, in the initially homogeneous wet paint layer, during film formation. These results prove that magnetic ferrite pigments can be magnetically manipulated in liquid coating layer applied on the substrate. Using the impedance spectroscopy technique, it was possible to detect stratification by analyzing complex capacity diagrams. As a result of impedance tests, better anti-corrosive properties of the system hardened in the presence of the magnetic field were demonstrated.
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Stream Reasoning to Improve Decision-Making in Cognitive Systems
- Caterine Silva de Oliveira
- Franco Giustozzi
- Cecilia Zanni-Merk
- Cesar Sanin
- Edward Szczerbicki
ABSTRACT Cognitive Vision Systems have gained a lot of interest from industry and academia recently, due to their potential to revolutionize human life as they are designed to work under complex scenes, adapting to a range of unforeseen situations, changing accordingly to new scenarios and exhibiting prospective behavior. The combination of these properties aims to mimic the human capabilities and create more intelligent and efficient environments. Contextual information plays an important role when the objective is to reason such as humans do, as it can make the difference between achieving a weak, generalized set of outputs and a clear, target and confident understanding of a given situation. Nevertheless, dealing with contextual information still remains a challenge in cognitive systems applications due to the complexity of reasoning about it in real time in a flexible but yet efficient way. In this paper, we enrich a cognitive system with contextual information coming from different sensors and propose the use of stream reasoning to integrate/process all these data in real time, and provide a better understanding of the situation in analysis, therefore improving decision-making. The proposed approach has been applied to a Cognitive Vision System for Hazard Control (CVP-HC) which is based on Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA) and has been designed to ensure that workers remain safe and compliant with Health and Safety policy for use of Personal Protective Equipment (PPE).
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Stress Monitoring System for Individuals with Autism Spectrum Disorders
- Michał Tomczak
- Marek Wójcikowski
- Bogdan Pankiewicz
- Jacek Łubiński
- Jakub Majchrowicz
- Daria Majchrowicz
- Anna Walasiewicz
- Tomasz Kiliński
- Małgorzata Szczerska
In this article, a stress monitoring system tailored for individuals with Autism Spectrum Disorders (ASD) and developed for the educational institution is presented. People with ASD face problems with effective stress management due to their high self-perceived levels of stress, poor ability to cope with it, and dificulties with the accurate detection of the source of stress. Consistently, being able to measure stress appears to be highly vital for this specifc group. The design and construction of the measuring system are introduced. The stress monitoring system including autonomic wearable device (wristband), both the electronics and mechanical part, as well as the software application for data analysis are shown. The wearable device includes sensors for measuring heart rate, skin resistance, temperature and movement. A dedicated software application allows for generating reports to evaluate therapeutic effects. The complex stress monitoring system has been tested in an educational institution. It can provide signifcant support in the stress management of people with ASD and become a meaningful assistance in the therapy of neurodiverse individuals.
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Stress-driven nonlocal elasticity for nonlinear vibration characteristics of carbon/boron-nitride hetero-nanotube subject to magneto-thermal environment
- Hamid M. Sedighi
- Mohammad Malikan
Stress-driven nonlocal theory of elasticity, in its differential form, is applied to investigate the nonlinear vibrational characteristics of a hetero-nanotube in magneto-thermal environment with the help of finite element method. In order to more precisely deal with the dynamic behavior of size-dependent nanotubes, a two-node beam element with six degrees-of freedom including the nodal values of the deflection, slope and curvature is introduced. In comparison with the conventional beam element, the vector of nodal displacement for the proposed element has one additional component indicating the nodal curvature to comply with the stress-driven nonlocal beam model. The nonlinear term associated with the von Kármán strain is included in the governing equation of motion and it is assumed that the nanotube structure is exposed to temperature changes and surrounded by a magnetic field. The obtained results endorsing the amplitude-dependence of the nonlinear frequencies are justified compared to those reported in the literature and a detailed study is conducted to explore the effect of different parameters on the vibrational behavior of the considered nano-hetero-structure.