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Tytuł:
Cyber-physical test environment for the identification of interacting wear effects in feed axes
Autorzy:
Bott, Alexander
Stöbel, Robin
Osen, Gregor
Fleischer, Jürgen
Powiązania:
https://bibliotekanauki.pl/articles/2200264.pdf
Data publikacji:
2023
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
machine dynamics
wear effect
feed axes
cyber-physical system
Opis:
For a comprehensive optimization and control of production processes, cyber-physical systems are necessary to include machines' time-dependent properties. These wear effects in machine tools, especially the feed axes, can significantly influence the process quality and are a steady research focus. However, the interaction of wear effects between different feed axes has received little attention. Especially models that represent the combined wear influence of different interacting feed axes on the control parameters and machine dynamics hold great potential. To close this knowledge gap, this paper proposes a cyber-physical test environment to identify the interaction of wear effects in feed axes. For this test environment, the relevant boundary conditions of different feed axes in machine tools and their systematic interaction are presented. Through these conditions, a physical test setup is derived and, analogous to this, a virtual model is created. This holistic approach represents the physical and virtual interaction between different components.
Źródło:
Journal of Machine Engineering; 2023, 23, 1; 123--132
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model‐free sliding mode control for a nonlinear teleoperation system with actuator dynamics
Autorzy:
Abdelwaheb, Henni Mansour
Abderrahmane, Kacimi
AEK, Belaidi
Powiązania:
https://bibliotekanauki.pl/articles/27314234.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
model free sliding mode controller
teleoperation robotic system
actuator dynamics
time-varying delay
model uncertainty
Opis:
Teleoperation robotic systems control, which enables humans to perform activities in remote situations, has become an extremely challenging field in recent decades. In this paper, a Model Free Proportional‐Derivative Slid‐ ing Mode Controller (MFPDSMC) is devoted to the syn‐ chronization problem of teleoperation systems subject to actuator dynamics, time‐varying delay, model uncer‐ tainty, and input interaction forces. For the first time, the teleoperation model used in this study combines actuator dynamics and manipulator models into a single equation, which improves model accuracy and brings it closer to the actual system than in prior studies. Further, the proposed control approach, called Free, involves the simple mea‐ surement of inputs and outputs to enhance the system’s performance without relying on any knowledge from the mathematical model. In addition, our strategy includes a Sliding Mode term with the MFPD term to increase system stability and attain excellent performance against external disturbances. Finally, using the Lyapunov func‐ tion under specified conditions, asymptotic stability is established, and simulation results are compared and provided to demonstrate the efficacy of the proposed strategy.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2023, 17, 1; 69--77
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on resilience model of UAV swarm based on complex network dynamics
Autorzy:
Wei, Kunlun
Zhang, Tao
Chuanfu, Zhang
Powiązania:
https://bibliotekanauki.pl/articles/28328275.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
UAV swarm
resilience
SIS
system dynamics
topology
Opis:
Unmanned Aerial Vehicle (UAV) swarms are utilized in various missions and operated within an open environment that is prone to disruptions. The resilience of UAV swarms, an important requirement, mainly revolves around ensuring stable and uninterrupted operations. Malicious attacks can implement the adverse impacts of potential threats through swarm communication links. In this context, the SIS (Susceptible → Infected → Susceptible) method is suitable for describing the information transmission within UAV swarms. An enhanced resilience model of the UAV swarm is proposed in this study, which incorporates the factors of self-dynamics, dynamics of topology, dynamics of information transmission, and SIS into the complex network model. Self-dynamics refer to the internal dynamics of the drones. In this paper, dynamics of topology consist of three factors: the varying distance between drones, the incoming degrees of each drone, and the number of communication types between drones. Lastly, dynamics of information transmission are characterized by SIS. The model proposed in this paper has the capability to effectively capture changes in the network topology as well as the dynamics of the system, which are significant contributors to the loss of resilience. And then, the average number of susceptible drones is utilized as the metric to evaluate the resilience of the swarm. Furthermore, an experiment is conducted where a UAV swarm successfully carries out a surveillance mission to demonstrate the advantages of our proposed method. The proposed model not only enables the support of mission planning but also facilitates the design enhancements of UAV swarms.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 4; art. no. 173125
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Alignment of circular economy business models for framing national sustainable economic development
Autorzy:
Atstaja, Dzintra
Cudecka-Purina, Natalija
Hrinchenko, Raisa
Koval, Viktor
Grasis, Janis
Vesere, Rudite
Powiązania:
https://bibliotekanauki.pl/articles/2142872.pdf
Data publikacji:
2022
Wydawca:
Centrum Badań i Innowacji Pro-Akademia
Tematy:
business models
circular economy
system dynamics
sustainability
modele biznesowe
gospodarka o obiegu zamkniętym
dynamika systemów
zrównoważony rozwój
Opis:
Circular economy offers opportunities to boost jobs and tackle climate change. The article reflects aspects of the impact on the environment through sectoral policies to support the circular economy because current business as usual model, based on the linear economy principle leads to a staggering inefficiency in nature resources are managed, with increased pollution, loss of ecosystems and substantial losses of value with each product disposed. This requires a change not only in consumer behaviour but even more on the resource extraction and material production side. The purpose of the research paper is to develop a decision-making matrix providing a step-by-step approach for the policymakers.
Źródło:
Acta Innovations; 2022, 42; 5-14
2300-5599
Pojawia się w:
Acta Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
BEYOND THE BLACK BOX: TOWARDS A SYSTEMS THEORY OF FARMING FAMILY AND FAMILY FARM
POZA CZARNĄ SKRZYNKĘ – W STRONĘ SYSTEMOWEJ TEORII RODZINY ROLNICZEJ I JEJ GOSPODARSTWA
Autorzy:
Pietrzak, Michał
Ziętara, Wojciech
Powiązania:
https://bibliotekanauki.pl/articles/2130405.pdf
Data publikacji:
2022-03-28
Wydawca:
Instytut Ekonomiki Rolnictwa i Gospodarki Żywnościowej - Państwowy Instytut Badawczy
Tematy:
rodzinne gospodarstwo rolnicze
myślenie systemowe
dynamika systemów
nowa ekonomia instytucjonalna
family farm
systems thinking
system dynamics
new institutional economics
Opis:
The aim of this article is to present the need for a view of a family farm that is complementary to neoclassical economics and outline the framework concepts on which the future systems theory of family farms could be based. The article is a conceptual overview. The paper presents the development of economics and organization of farms. It was emphasized that in addition to the analytical approach, which today fits into the neoclassical mainstream of economic thought, the organic approach, which is related to the contemporary systems approach, was also important in the discipline. The authors presented two trends considered to be the foundation of the target theory of family farms: systems thinking and new institutional economics. An outline of the concept of a new approach to family farms is presented as a systemic whole connecting the family and its household involved in agricultural production, with the possibility of reducing internal transaction costs (agency costs) being an important attribute of this whole. Family farms still remain the predominant form of agricultural activity in Poland, Europe, and other continents. The family nature of the entities creates their specificity both in terms of goals and behaviors, which is difficult to reduce to the neoclassical model of firm, which seeks to maximize profits. What is needed is a holistic, systems approach complementary to the predominant neoclassical approach, considering close relations between the family and the agricultural production unit.
Celem niniejszego artykułu jest przedstawienie potrzeby komplementarnego względem ekonomii neoklasycznej spojrzenia na rodzinne gospodarstwo rolnicze (RGR), a następnie zarysowanie ramowych koncepcji, na których mogłaby się oprzeć przyszła systemowa teoria RGR. Artykuł ma charakter przeglądowo-koncepcyjny. W tekście dokonano przeglądu rozwoju dyscypliny ekonomiki i organizacji gospodarstw rolniczych. Podkreślono, że oprócz podejścia analitycznego, które obecnie wpisuje się w główny, tj. neoklasyczny nurt myśli ekonomicznej, istotne miejsce w tej dyscyplinie zajmowało podejście organiczne, którego współczesne echa można odnaleźć w podejściu systemowym. Następnie przedstawiono dwa nurty uznane za fundamenty docelowej teorii RGR: myślenie systemowe oraz nową ekonomię instytucjonalną. Przedstawiono zarys koncepcji nowego podejścia do rodzinnego gospodarstwa rolniczego postrzeganego jako systemowa całość łącząca rodzinę i jej gospodarstwo domowe zaangażowane w produkcję rolniczą, przy czym istotnym atrybutem tej całości jest zdolność do redukcji wewnętrznych kosztów transakcyjnych (kosztów agencji). W konkluzji stwierdzono, że gospodarstwa rodzinne wciąż pozostają dominującą formą prowadzenia działalności rolniczej w Polsce, Europie i na innych kontynentach. Rodzinny charakter tych podmiotów tworzy ich specyfikę zarówno na poziomie celów, jak i zachowań, którą trudno zredukować do neoklasycznego modelu maksymalizującej zyski firmy. Potrzebne jest – komplementarne wobec dominującego ujęcia neoklasycznego – podejście holistyczne, systemowe, uwzględniające ścisłe związki między rodziną a rolniczą jednostką produkcyjną.
Źródło:
Zagadnienia Ekonomiki Rolnej; 2022, 370, 1; 42-86
0044-1600
2392-3458
Pojawia się w:
Zagadnienia Ekonomiki Rolnej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamics of pertinent project delay variables in the Thai construction sector: mathematical analysis
Autorzy:
Ajayi, Babatunde Oluwaseun
Chinda, Thanwadee
Powiązania:
https://bibliotekanauki.pl/articles/2105324.pdf
Data publikacji:
2022
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
construction delay
DEMATEL analysis
system dynamics
preconstruction
project management
poóźnienie budowlane
analiza DEMATEL
dynamika układu
przekonstrukcje
zarządzanie projektem
Opis:
Project completion behind schedule is a struggle for the construction sector, affecting time, cost, and quality. This investigation has been necessitated by the lingering nature of project delay risks despite many extant analyses. This study collated expert opinions from the Thai construction sector on salient construction delay variables and their influence on each other for DEMATEL-SD analysis. The collated data were analysed and found consistent with a Cronbach’s alpha of 0.939. Then, the DEMATEL technique was used to establish the influence weight of factors for the System dynamics (SD) analysis. It was discovered that minimising the design error at the preconstruction stage significantly reduces the magnitude of delay. Increasing values of design error and change order increase the rework profile. Besides, the project delivery within the scheduled 232 weeks can be ensured by minimising the threat of design error, design change, change order, rework, productivity problem, and by improving project management. This study adopted a hybrid mathematical system to holistically examine the construction delay risk by comprehensively exploring the dynamics of influencing variables and investigating their impact on the project scheme. The system helps project stakeholders to arrive at an effective decision in overcoming delay risks, thus minimising the cost overrun and improving the project quality.
Źródło:
Engineering Management in Production and Services; 2022, 14, 2; 26--45
2543-6597
2543-912X
Pojawia się w:
Engineering Management in Production and Services
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of propeller emergence on hull, propeller, engine, and fuel consumption performance in regular head waves
Autorzy:
Ghaemi, Mohammad Hossein
Zeraatgar, Hamid
Powiązania:
https://bibliotekanauki.pl/articles/32898210.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship dynamics
ship propulsion system
propeller ventilation
propeller emergence
sea waves
Opis:
In this study, the impact of propeller emergence on the performance of a ship (speed), propeller (thrust, torque, and RPM), a diesel engine (torque and RPM) and fuel consumption are analysed under severe sea conditions. The goal is to describe the variation in the system variables and fuel consumption rather than analysing the motion of the ship or the phenomenon of propeller ventilation in itself. A mathematical model of the hull, propeller, and engine interactions is developed in which the propeller emergence is included. The system parameters are set using model experiments, empirical formulae, and available data for the engine. The dynamic response of the system is examined in regular head waves under submerged and emerged conditions of the propeller. The pulsatility and the extent of variation of 20 selected variables for the coupled system of hull, propeller, and engine are elaborated using quantitative and qualitative terms and absolute and relative scales. The simulation begins with a ship moving on a straight path, in calm water, with a constant speed for the ship, propeller and engine under steady conditions. The ship then encounters regular head waves with a known time series of the total resistance of the ship in waves. Large motions of the ship create propeller emergence, which in turn reduces the propeller thrust and torque. This study shows that for a specific ship, the mean ship speed, shaft angular velocity, and engine power were slightly reduced in submerged conditions with respect to calm water. We compared the mean values of the variables to those in the emerged condition, and found that the shaft angular velocity was almost the same, the ship speed was considerably reduced, and the engine power significantly dropped with respect to calm water. The ratios of the amplitude of fluctuation to the mean (Amp/Mean) for the ship speed and angular velocity of the shaft under both conditions were considerable, while the Amp/Mean for the power delivered by the engine was extremely high. The outcomes of the study show the degree of influence of propeller emergence on these variables. We identify the extent of each change and categorise the variables into three main groups based on the results.
Źródło:
Polish Maritime Research; 2022, 4; 56-76
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long-term trend of electric vehicle sales in Thailand
Autorzy:
Chinda, Thanwadee
Powiązania:
https://bibliotekanauki.pl/articles/2105320.pdf
Data publikacji:
2022
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
electric vehicle
system dynamics modelling
trend
Thailand
pojazd elektryczny
modelowanie dynamiki systemu
kierunek rozwoju
Tajlandia
Opis:
This research study aims at examining the long-term trend of EV sales in Thailand, utilising the system dynamics (SD) modelling approach. This approach is commonly used to model complex systems with causal relationships among key factors within the system. The developed SD model consists of five key factors affecting electric vehicle (EV) sales, namely, the environment, economy, charging infrastructure, government support, and battery maintenance. The simulation results show the increase in EV sales by ten times in the next 20 years with implementation plans related to the five key factors. The government support factor is the most important in enhancing EV sales in the short term. Several government support plans should be initiated to attract more EV consumers, such as subsidies and tax reductions. The environment and charging infrastructure factors are crucial to increasing EV sales in the long term. The enforcement of the CO2 tax and the provision of charging stations all around the country should be established to achieve a sustainable EV market in the long term. This research study contributes to the Thai government and automotive industry to better understand the complex relationships among key factors affecting EV sales. The related sectors may use the study results to plan for EV campaigns to promote the use of EVs and achieve a sustainable EV market.
Źródło:
Engineering Management in Production and Services; 2022, 14, 1; 13--25
2543-6597
2543-912X
Pojawia się w:
Engineering Management in Production and Services
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mathematical model for controlling a quadrotor UAV
Model matematyczny do sterowania czterowirnikowym BSP
Autorzy:
Kowalik, Rafał
Łusiak, Tomasz
Novak, Andrej
Powiązania:
https://bibliotekanauki.pl/articles/36444941.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
UAV control system
dynamics model
quadrotor
linearization
system kontroli BSP
model dynamiki
czterowimikowy BSP
linearyzacja
Opis:
Given the recent surge in interest in UAVs and their potential applications, a great deal of work has lately been done in the field of UAV control. However, UAVs belong to a class of nonlinear systems that are inherently difficult to control. In this study we devised a mathematical model for a PID (proportional integral derivative) control system, designed to control a quadrotor UAV so that it follows a predefined trajectory. After first describing quadrotor flight dynamics, we present the control model adopted in our system (developed in MATLAB Simulink). We then present simulated results for the use of the control system to move a quadrotor UAV to desired locations and along desired trajectories. Positive results of these simulation support the conclusion that a quadrotor UAV spatial orientation control system based on this model will successfully fulfil its task also in real conditions.
Wobec rosnącego zainteresowania bezzałogowymi statkami powietrznymi (BSP) i ich potencjalnymi zastosowaniami, w ostatnim czasie wykonano wiele prac w dziedzinie ich lepszego sterowania. BSP jednak należą do klasy nielinearnych systemów, które są z natury trudne do sterowania. W niniejszej pracy opracowano model matematyczny dla systemu sterowania opartego na metodzie PID (proportional integral derivative), zaprojektowanego do sterowania czterowirnikowym BSP tak, aby podążał on po wcześniej zdefiniowanej trajektorii. Opisano dynamiki lotu czterowirnikowym BSP i zaprezentowano model kontroli zastosowany w naszym systemie (opracowany w programie MATLAB Simulink). Przedstawione są wyniki symulacji użycia systemu do sterowania czterowirnikowym BSP w celu jego przemieszczenia się do pożądanej lokalizacji oraz wzdłuż pożądanej trajektorii. Wyniki tych symulacji potwierdzają wniosek, że oparty na tym modelu system sterowania dla czterowirnikowego BSP może z powodzeniem spełnić swoje zadanie również w warunkach rzeczywistych.
Źródło:
Transactions on Aerospace Research; 2021, 3 (264); 58-70
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza numeryczna odciążania pomieszczeń gaszonych gazem
Numerical study of pressure relief in gas-extinguished enclosures
Autorzy:
Październik, Michał.
Powiązania:
Zeszyty Naukowe SGSP 2021, nr 79, s. 31-49
Współwytwórcy:
Boroń, Sylwia Autor
Kubica, Przemysław Autor
Szkoła Główna Służby Pożarniczej oth
Data publikacji:
2021
Tematy:
Analiza numeryczna
Ciśnienie
Fire Dynamics Simulator
Gaszenie (pożarnictwo)
Gazy
Mechanika płynów
Modele matematyczne
Pomieszczenia
Sprzęt ratowniczo-gaśniczy
Symulacja
System wentylacyjny
Artykuł problemowy
Artykuł z czasopisma naukowego
Opis:
W artykule przedstawiono wyniki badań analizy porównawczej w zakresie przyrostu ciśnienia po wyładowaniu gazu gaśniczego w pomieszczeniu odciążonym bezpośrednio na zewnątrz. Przeprowadzono analizy numeryczne za pomocą oprogramowania PyroSim 2020, z wykorzystaniem modelu turbulencji LES. Wnioski płynące z powyższych badań mogą być wykorzystane przy projektowaniu stałych urządzeń gaśniczych gazowych.
Bibliografia, wykaz norm na stronach 47-48.
Dostawca treści:
Bibliografia CBW
Artykuł
Tytuł:
CFD Analysis of an Innovative Wind Tower Design with Wind-Inducing Natural Ventilation Technique for Arid Climatic Conditions
Autorzy:
Obeidat, Bushra
Kamal, Hammam
Almalkawi, Amal
Powiązania:
https://bibliotekanauki.pl/articles/1839069.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
wind tower
computational fluid dynamics
natural ventilation
wind pressure fluctuation
indoor air quality
passive ventilation system
Opis:
Wind towers are passive architectural elements traditionally used to ventilate buildings in the Middle East’s hot and arid regions. Some recent design initiatives in Jordan are particularly interested in using passive systems for natural ventilation. This paper focuses on an innovative wind tower design as a passive ventilation system, which will be integrated into a train station design in Aqaba, Jordan to improve the air quality in indoor spaces and reduce the cooling loads. The design uses wind-induced effects as the motivating forces to improve natural ventilation. The study optimized the wind tower and evaluated its performance using Autodesk Computational Fluid Dynamics (CFD) simulations and Grasshopper Rhino plug-ins. Airflow and distribution through the tower were analyzed using the CFD model. Grasshopper definitions were used to examine the tower efficiency in lowering the indoor air temperature. Simulations indicated the potential of the proposed wind tower to reduce the temperature by 6.164°C and supply the interior space with the required fresh air rates. This article outlines how wind towers can be used in contemporary architecture and incorporate the simulation methods to pave the way for architects to effectively validate the performance of their design proposals at the early design stage.
Źródło:
Journal of Ecological Engineering; 2021, 22, 2; 86-97
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Colorimetric Parameters Modeling of Test Micro-Ecosystems for Lands Pollution Remote Sensing
Autorzy:
Vуsotska, Olena
Greben, Aleksandr
Kalashnikova, Vasilisa
Klochko, Tetiana
Rakhmetullina, Saule
Kotyra, Andrzej
Mamyrbaev, Orken
Iskakova, Aigul
Powiązania:
https://bibliotekanauki.pl/articles/1839122.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
pollution
system dynamics
colorimetric parameters
remote sensing
Opis:
The paper describes a methodology of determining the toxicity sources, using bioassay based on the wildlife objects that change their colorimetric parameters under the influence of toxic factors. The work explores the dynamism of the colorimetric attributes associated with plant pigments. It can be determined by computer processing of the data obtained from digital remote sensing of the lands affected by toxic pollution by means of such relatively low-cost and straightforward methods as digital photography from an aircraft or a drone. The results obtained do not allow direct measurements but rather serve as a basis for the development and characterization of new biomarkers.
Źródło:
Journal of Ecological Engineering; 2021, 22, 2; 161-168
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Do seasonal dynamics influence traits and composition of macrobenthic assemblages of Sundarbans Estuarine System, India?
Autorzy:
Bhowmik, M.
Mandal, S.
Powiązania:
https://bibliotekanauki.pl/articles/2079001.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
seasonal dynamics
macrobenthic assemblage
macroinvertebrate
climate change
taxonomic analysis
ecosystem functioning
biological trait
estuarine system
India
Opis:
The present study investigates the influence of seasonal dynamics on macrobenthic assemblages in four seasons of 2017—2018 from the central sector of Indian Sundarbans which is under the constant threat of climate change. Besides taxonomic analysis, a traitbased approach has also been applied to assess the change in their ecosystem functioning. The maximum species density (11675 ± 11883.31 ind. m−2) was observed during the spring season which declines considerably in the monsoon season (5875 ± 6224.08 ind. m−2). A total of 95 macrobenthic taxa were recorded from Sundarbans and they were dominated by families like Capitellidae, Donacidae, Magelonidae, Nereididae, Paraonidae and Spionidae. Overall, polychaetes have shown higher taxonomic and functional variation than other groups. Opportunistic polychaete species have shown a prominent compositional shift during post-monsoon seasons. Both the univariate and multivariate analyses have shown a significant relation between macrobenthic composition and environmental parameters. SIMPER has depicted that environmental parameters made the station 4 unique for several types of molluscs like Acteocina estriata, Stenothyra deltae and Meretrix meretrix during spring. Trait percentages also showed a seasonal succession pattern and among the trait categories, burrowers and deposit feeders dominated the estuary. A gradual increase in suspension feeders in spring has been noticed. RLQ approach with fourth-corner analysis was used to unravel the relationship between traits and environmental parameters. Hence, the present study provided a comprehensive idea about the species composition along with their trait categories from such a dynamic habitat. That could be the first stepping stone for a long term monitoring of macrobenthic assemblages from this largest delta on earth.
Źródło:
Oceanologia; 2021, 63, 1; 80-98
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear homogeneous dynamical system of fully cracked concrete beam
Autorzy:
Mohan, G.
Pandey, U. K.
Powiązania:
https://bibliotekanauki.pl/articles/1818788.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
non-linear dynamics
two-DOF systems
homogeneous dynamical systems
bilinearity ratio
cracked concrete beams
fixed beam
dynamika nieliniowa
układ dynamiczny
system homogeniczny
belka betonowa
Opis:
Purpose: Purpose of this paper is the theoretical formulation of elasto-dynamics behaviour of fully cracked concrete beams for two-degree of freedom (DOF) dynamical system. Such modelled system is demonstrated by a new class of two-DOF conservative, fully-nonlinear systems known as nonlinear homogeneous dynamical (NHD) systems. Design/methodology/approach: The theoretical formulation of Two-DOF dynamical system has been developed by using the fundamental concept of structural analysis. Further, the behaviour of such class of conservative dynamical system has been concluded by using MATLAB. Findings: Findings can be distinguished into two aspects. First, when subjected to service loads, reinforced concrete structures possess tension cracks. Due to load variation with time leads the breathing action (opening-closing-reopening) of existing cracks and the behaviour of such structures are nonlinearly-elastic. Second, such class of fully nonlinear dynamical system possess dependence of stiffness coefficients on nodal displacements. Research limitations/implications: The mechanism behind such class of fully nonlinear dynamical system is not yet fully explored. Practical implications: Practical implications are related to the structural response of fully cracked concrete beam to different earthquake excitation, especially to understand the response of such nonlinear homogeneous elasto-dynamical system with two-DOF concrete beam. Originality/value: Elasto-dynamics of fully cracked concrete beams.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2021, 106, 1; 5--19
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluid dynamic and acoustic optimization methodology of a formula-student race car engine exhaust system using multilevel numerical CFD models
Autorzy:
Mohamad, Barhm
Ali, Mohammed Qasim
Neamah, Hayder Ahmed
Zelentsov, Andrei
Amroune, Salah
Powiązania:
https://bibliotekanauki.pl/articles/328318.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
engine performance
sound pressure level
computational fluid dynamics
modeling
simulation
exhaust system
wydajność silnika
poziom ciśnienia akustycznego
obliczeniowa mechanika płynów
modelowanie
symulacja
układ wydechowy
Opis:
In this work a multilevel CFD analysis have been applied for the design of an engine exhaust system include manifold and muffler with improved characteristics of noise reduction and fluid dynamic response. The approaches developed and applied for the optimization process range from the 1D to fully 3D CFD simulation, exploring hybrid approaches based on the integration of a 1D model and 3D tools. Once the best configuration has been defined, the 1D-3D approach has been adopted to confirm the prediction carried out by means of the simplified approach, studying also the impact of the new configuration on the engine performances.
Źródło:
Diagnostyka; 2020, 21, 3; 103-111
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 156

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