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Search results for: DYNAMIC IMPACT
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Dynamic Modeling of COVID-19 Disease with Impact of Lockdown in Pakistan and Malaysia
PublicationBeing researchers, it is an utmost responsibility to provide insight on social issues thus, this work addresses the dynamic modeling of first and most contagious disease named as COVID-19 caused by coronavirus. The first case of COVID-19 appeared in Pakistan was on 26th February 2020 and in Malaysia on 27th February 2020; both patients had foreign travel history. In the paper, the number of total affected cases and total deaths...
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DYNAMIC ANALYSIS OF THE IMPACT OF VIBRATION ON HISTORICAL BUILDINGS - AN OWN PROJECT OF EXTERNAL STAIRCASE
PublicationThis article presents numerical simulations that concern modeling of interaction of the external staircase’s construction with the observation deck on historic water tower located at Gdansk University of Technology. The interaction occurring according to various methods of the staircase's construction support on the wall of the historic tower was compared. The external staircase that allows for entering onto the monument was subjected...
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Identification analysis of dynamic changes in the composition of biogas and their impact on the operation of internal combustion engines
PublicationW pracy zamieszczono wyniki badań składu biogazu pozyskiwanego na komunalnym wysypisku śmieci. Pozyskiwany biogaz jest wykorzystywany do zasilania biogazowych zespołów prądotwórczych wyposażonych w silniki o zapłonie iskrowym dostosowanych do zasilania tym paliwem. Pozyskiwany biogaz powstaje w sposób naturalny w procesie beztlenowej fermentacji zachodzącej przez ok. 20 lat, w organicznej części pryzmy odpadów składowanych na wysypisku...
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ANALYSIS OF IMPACT of SHIP model parameters on changes of control quality index in ship dynamic positioning system
PublicationIn this work there is presented an analysis of impact of ship model parameters on changes of control quality index in a ship dynamic positioning system designed with the use of a backstepping adaptive controller. Assessment of the impact of ship model parameters was performed on the basis of Pareto-Lorentz curves and ABC method in order to determine sets of the parameters which have either crucial, moderate or low impact on objective...
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New devices to capture the temperature effect under dynamic compression and impact perforation of polymers, application to PMMA
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Coupled DEM/CFD analysis of impact of free water on the static and dynamic response of concrete in tension regime
PublicationW tym artykule zbadano numerycznie quasi-statyczne i dynamiczne zachowanie częściowo nasyconego płynem betonu w warunkach dwuwymiarowego (2D) jednoosiowego rozciągania w mezoskali. Obliczono, jaki wpływ ma zawartość wolnego płynu porowego (gazu i wody) na proces pękania i wytrzymałość betonu w rozciąganiu. Do symulacji zachowania betonu całkowicie i częściowo nasyconego płynem w warunkach quasi-statycznych i dynamicznych wykorzystano...
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Dynamic analysis of the impact of the wind spectrum according to the theory of Davenport for lightweight structures of the roof in sports hall Czyzyna in Cracow.
PublicationThe main aim of this analysis is to characterize numerical simulations connected with modeling dynamic influence of wind on the lightweight structures of the roof in sports hall – “Czyżyna”. This hall is built in Cracow. The article also involves the proposals of the solutions connected with dynamic influence of the wind – Davenport’s method has been used. These proposals have not been taken into consideration at the detailed engineering...
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The impact of air humidity on the operation of proton exchange membrane fuel cells determined using dynamic electrochemical impedance spectroscopy
PublicationThis paper describes the changes in the fuel cell impedance across a range of current loads and humidity changes. The changes of each equivalent circuit parameters representing specific processes occurring in fuel cells, as a function of humidity and current changes, were determined. Within the combined scope of current and humidity, the optimal working conditions of the cells were determined, corresponding to the lowest impedance...
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The impact of filler thermomechanical modifications on static and dynamic mechanical performance of flexible foamed polyurethane/ground tire rubber/zinc borate composites
PublicationThe rapid development of the automotive industry is very beneficial to many aspects of human life, but it is also a very significant environmental burden. The most straightforward impact is related to the generation of exhaust, but the management of post-consumer car parts is also a major challenge. Among them, waste tires are very burdensome due to their enormous numbers. Therefore, it is essential to develop novel, environmentally...
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A LABORATORY STAND FOR THE ANALYSIS OF DYNAMIC PROPERTIES OF THERMOCOUPLES
PublicationIn the present elaboration, problems connected with measurements of high variable temperatures of gases are introduced and the impact of dynamic properties of different construction solutions of thermoelements on the accuracy of the measurements is considered. A laboratory stand built within research under doctoral thesis, destined for analysis of dynamic properties of thermocouples is also described. Results of numerical simulation...
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An Evaluation Engine for Dynamic Ranking of Cloud Providers
PublicationThe paper focuses on creation of an effective dynamic ranking service for IaaS, PaaS and SaaS cloud providers. It considers building a quality model for this purpose along with definition of quality measure- ment procedures. The paper discusses several techniques known from already existing price comparison engines that could be modified and adopted for comparison of cloud providers. A technique for filtering measured data is proposed,...
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Experimental dynamic study on a timber-frame house using shaking table
PublicationThe aim of this paper is to show the results of the shaking table experimental study concerning the behaviour of the model of the timber-frame house under earthquake excitation and impact loading. In order to determine the basic dynamic properties of the undamaged structure, the free vibration and the sweep-sine tests were first conducted. Then, the model was excited using the time history record of the El Centro earthquake of...
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Export diversification and economic development: A dynamic spatial data analysis
PublicationThis paper contributes to the empirical literature on the relationship between “export variety” (export diversification) and economic development by relaxing the assumption of cross-country independence and allowing for spatial diffusion of shocks in observed and unobserved factors. Export variety is measured for a balanced panel of 114 countries (1992–2012) using very detailed information on their exports (HS 6-digit product level)....
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DYNAMIC RESPONSE OF FORUM GDANSK STRUCTURE DUE TO RAIL TRAFFIC
PublicationThe paper presents the study of the impact of vibration induced by the movement of the railway rolling stock on the Forum Gdańsk structure. This object is currently under construction and is located over the railway tracks in the vicinity of the Gdańsk Główny and Gdańsk Śródmieście railway stations. The analysis covers the influence of vibrations on the structure itself and on the people within. The in situ measurements on existing...
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Identification of dynamic parameters in the context of diagnostics of steel tank with different level of liquid.
PublicationThe paper presents an experimental study to identify the dynamic parameters of a water-filled tank model. The experimental modal analysis approach involving the excitation at one point of the structure and acquisition of vibra tions at selected points distri buted over the tank surface allowed to determine the resonance frequencies, mode shapes and damping ratios. The main aim of the research was to examine the influence of...
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Static and Dynamic Mechanical Properties of 3D Printed ABS as a Function of Raster Angle
PublicationDue 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...
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Experimental determination of dynamic properties of cylindrical steel tank model filled with liquid
PublicationIn technical branches, such as chemical or petroleum industries, cylindrical steel tanks are essential structures used for storage of liquid products. Any failure might have disastrous consequences, therefore their safety and reliability is essential. The aim of the present paper is to show the results of the experimental study which has been conducted on a scaled model of a real tank used in Poland. The investigation was carried...
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Consideration of dynamic loads in the determination of axle load spectra for pavement design
PublicationAxle load spectra constitute a crucial part of the data for pavement design and pavement distress analysis. Typically, axle load spectra represent static load from vehicles and do not include dynamic loads generated by vehicles in motion. While dynamic loads can significantly contribute to faster pavement distress, this fact is mostly omitted in pavement design methods. The paper presents a methodology for consideration of dynamic...
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Behaviour of steel columns under impact
PublicationOne of import issues related to the idea of sustainable society is the safety of civil engineering structures. The safety and reliability of steel structures under impact loading is among a number of different aims during the design state. The aim of this paper is to present the results of investigation focused on dynamic behaviour of steel columns under impact loading. Modal and transient dynamic analyses using Finite Element...
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Effect of pavement roughness and vehicle dynamic loads on decrease of fatigue life of flexible pavements
PublicationDue to the fact that pavement surfaces are not ideally even, dynamic loads of vehicle axles deviate from static loads. Higher dynamic loads contribute to faster pavement distress. The distribution of dynamic loads is similar to normal distribution and can be described by static load and factors DI (dynamic impact) and DLC (dynamic load coefficient). With the deterioration of pavement condition its evenness decreases as well and...
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Merton-type default risk and financial performance: the dynamic panel moderation of firm size
PublicationPurpose – The main purpose of this study is to evaluate the probability of default and examine the relationship between default risk and financial performance, with dynamic panel moderation of firm size. Design/methodology/approach – This study utilizes a total of 1,500 firm-year observations from 2013 to 2018 using dynamic panel data approach of generalized method of moments to test the relationship between default risk and financial...
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Optimization of the Relative Humidity of Reactant Gases in Hydrogen Fuel Cells Using Dynamic Impedance Measurements
PublicationWater management is a key factor affecting the efficiency of proton exchange membrane fuel cells (PEMFCs). The currently used monitoring methods of PEMFCs provide limited information about which processes or components that humidity has a significant impact upon. Herein, we propose the use of a novel approach of impedance measurements using a multi-sinusoidal perturbation signal, which enables impedance measurements under dynamic...
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ON ESTIMATION OF OCCUPANT SAFETY IN VEHICULAR CRASHES INTO ROADSIDE OBSTACLES USING NON-LINEAR DYNAMIC ANALYSIS
PublicationThe article describes a comparison of two general methods of occupants safety estimation based on a numerical examples. The so-called direct method is mainly based on the Head Injury Criterion of a crash test dummy in a vehicle with passive safety system while the indirect method uses a European standards approach to estimate impact severity level. Numerical simulations in LS-DYNA have been conducted.
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Grid-Forming Operation of Energy-Router Based on Model Predictive Control with Improved Dynamic Performance
PublicationThe focus of this study is on the grid-forming operation of the Energy Router (ER) based on Model Predictive Control (MPC). ER is regarded as a key component of microgrids. It is a converter that interfaces the microgrid (s) with the utility grid. The ER has a multiport structure and bidirectional energy flow control. The ER concept can be implemented in Nearly Zero-Energy Buildings (NZEB) to provide flexible energy control. A...
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Nonlinear dynamic analysis of the pure “buckling” mechanism during blow-out trauma of the human orbit
PublicationConsidering the interplay between orbital bones and intraorbital soft tissues, commonly accepted patterns of the blow-out type of trauma within the human orbit require more thorough investigation to assess the minimal health-threatening impact value. Two different three-dimensional finite element method (FEM) models of the human orbital region were developed to simulate the pure “buckling” mechanism of orbital wall fracture in...
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Computational Fluid Dynamic study on the wind characteristics of a multifunctional building system model in developed coastal cities
PublicationThis paper presents an approach for providing innovative technology by applying fluid mechanics to the field of architectural design. The aim is to make a building’s shape profitable and strengthen environmental protection by using the wind force to create an integrated wind absorption definition for a multifunctional building system model. Furthermore, taking control of the wind flow over an object can have an impact on not only...
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A Method of Assessment of the Liquid Sloshing Impact on Ship Transverse Stability
PublicationLiquid sloshing phenomenon taking place in partly filled ships? tanks directly affects the stability of a vessel. However, only static calculations are carried out onboard ships nowadays and static transfer of liquid weight is taken into account in the course of routine stability calculation. The paper is focused on a dynamic heeling moment due to liquid sloshing in tanks onboard ships. The set of numerical simulations of liquid...
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Mechanical response of 6061-T6 aluminium alloy subjected to dynamic testing at low temperature: Experiment and modelling
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The experimental identification of the dynamic coefficients of two hydrodynamic journal bearings operating at constant rotational speed and under nonlinear conditions.
PublicationHydrodynamic bearings are commonly used in ship propulsion systems. Typically, they are calculated using numerical or experimental methods. This paper presents an experimental study through which it has been possible to estimate 24 dynamic coefficients of two hydrodynamic slide bearings operating under nonlinear conditions. During the investigation, bearing mass coefficients are identified by means of a newly developed algorithm....
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Dynamic analysis of lightweight structure of the Viaduct Millau in France subjected to the wind fluctuations described by Karman’s and Davenport’s spectrum
PublicationThe article presents numerical simulations for wind impact modelling on the Millau Viaduct structure in France performed with two independent spectrum generation methods. The viaduct's construction in affected by strong forces, as it is situated in the Tarn river's valley. Thus, the loading coming from the wind cannot be modelled, the way it is in case of simple structures as static loading, but as a loading in a form of a spectrum...
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The Impact of Sloshing Liquids on Ship Stability for Various Dimensions of Partly Filled Tanks
PublicationLiquid sloshing phenomenon taking place in partly filled ships' tanks directly affects the stability of a vessel. However, only static calculations are carried out onboard ships nowadays and static transfer of liquid weight is taken into account in the course of routine stability calculation. The paper is focused on a dynamic heeling moment due to liquid sloshing in tanks onboard ships. A number of numerical simulations of liquid...
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Dynamics analysis of footbridge mode shapes the s8 expressway on the basis of the results of in situ tests
PublicationNon-destructive diagnostics for structure may use dynamic measurements realized during vibrations of a facility induced by dynamic environmental impact, enforced by the use of inductors or impulse impact. Dynamic tests and the analysis were undertaken for a footbridge situated over the expressway S8. The studies in situ allowed for dynamic characteristics to be determined: frequency, shape modes and damping for respective frequency...
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Experimental and numerical study on deformed steel columns subjected to impact load during earthquakes
PublicationThe soft-storey failure is one of the most typical types of damage observed in buildings during earthquakes. The failure of an upper soft storey of a structure results in large impact load acting on the lower floors and if the resistance of the structural members of the lower storeys is not sufficient it may further lead to progressive collapse of the whole building. The aim of the present paper is to investigate the dynamic behaviour...
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The consequences of dynamic BPM
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Dynamic coloring of graphs
PublicationDynamics is an inherent feature of many real life systems so it is natural to define and investigate the properties of models that reflect their dynamic nature. Dynamic graph colorings can be naturally applied in system modeling, e.g. for scheduling threads of parallel programs, time sharing in wireless networks, session scheduling in high-speed LAN's, channel assignment in WDM optical networks as well as traffic scheduling. In...
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Predicting the impact of traffic–induced vibrations on buildings using artificial neural networks
PublicationTraffic–induced vibrations may constitute a considerable load to a building, cause cracking of plaster, cracks in load–bearing elements or even a global structural collapse of the whole structure [1-4]. Vibrations measurements of real structures are costly and laborious, not justified in all cases. The aim of the paper is to create an original algorithm, to predict the negative dynamic impact on the examined residential building...
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The impact of technological and structural changes in the national economy on the labour-capital relations
PublicationThe aim of the research presented in this paper is to present the relations between labour and capital in the national economy, resulting from technological and structural changes taking place in the years 1991 to 2008. The structure of the paper is as follows. It first presents the functional determinants for the Polish economy in 1991-2008 affecting the phenomenon subject to study. Then it presents the preliminary analysis of...
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Impact and stretching standardized tests as useful tools for assessment of viscoelastic behavior for highly rubberized asphalt binder
PublicationAsphalt binder is generally identified as a brittle material at low service temperature or under high-speed load, and the brittleness becomes serious after weathering aging. Improving the toughness of asphalt binder through adding high-content of crumb tire rubber is an efficient method to solve this problem. Devulcanized rubber modified asphalt binder (DRMA) with different contents (15–40%) of devulcanized rubber (DR) were prepared...
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Solving the Problem of Dynamic Adaptability of Artificial Intelligence Systems that Control Dynamic Technical Objects
PublicationThis paper investigates the increase in the response speed and stability of artificial intelligence systems that control dynamic technical objects. The problem of calculating the optimal time of switching an artificial intelligence system between software classes by the criterion of the rigidity degree of the model of a control object is considered. The solution of this problem is proposed for the general case of the control object...
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Active dynamic thermography in cardiosurgery
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On dynamic equations with deviating arguments
PublicationPraca dotyczy istnienia rozwiązań równań dynamicznych z odchylonymi argumentami. Podane zostały warunki dostateczne na istnienie rozwiązania. Dwa przykłady ilustrują otrzymane wyniki.
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Selected Features of Dynamic Voting
PublicationIn multi-agent systems composed of autonomous agents with local knowledge, it is often desirable to aggregate their knowledge in order to make an educated decision. One of the methods of agreeing to a common decision is voting. A new history-based dynamic weight protocol allows for identification of the agents which contribute to the correct system decision. The main advantage of this approach, compared to static weighted system...
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The Dynamic Model of Magnetic Hysteresis
PublicationThis paper presents the scalar dynamic magnetic hysteresis model based on the Preisach theory. The important role in this theory played hysteresis operator states. The changes of these operators` states are not immediate in the dynamic model but they are a function of time and parameter k representing the magnetic properties of the material. In this paper the transient state of the hysteresis operator is defined by the nonlinear...
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Dynamic ranking of cloud providers
PublicationThe paper focuses on how to create an effective dynamic ranking service for IaaS,PaaS and SaaS cloud providers. It considers building of a quality model for thispurpose along with definition of quality measurement procedures. The paper discussesseveral techniques known from already existing price comparison engines that couldbe modified and adopted for comparison of cloud providers. Furthermore, a tech-nique for filtering measured...
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Dynamic charging of electric buses
PublicationDespite the continuous development of electrochemical battery technology and the multitude of electric buses on offer, it is still not possible to exploit electric buses in urban transport on an all-day basis without the necessity of charging them. It is therefore necessary to build point-to-point contact charging stations or induction charging stations at the terminals. This results in substantial financial outlays connected with...
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Tyre dynamic radius determination
PublicationW artykule opisano stanowisko wykorzystywane do badania oporu toczenia opon samochodowych znajdujące się w Katedrze Konstrukcji Maszyn i Pojazdów Wydziału Mechanicznego Politechniki Gdańskiej. Przedstawiono wyniki badań promienia dynamicznego opony Michelin 165/80R13 83T z bieżnikiem CLASSIC przeprowadzone z wykorzystaniem tego stanowiska na nawierzchni Safety Walk 80. Badania przeprowadzono zmieniając: prędkość jazdy, obciążenie...
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Dynamic characteristics of interaperitoneal perfusion.
PublicationPrzedstawiono wyniki badań laboratoryjnych perfuzyjnego przepływu przez model jamy brzusznej człowieka. Szczególną uwagę zwrócono na techniczne aspekty modelu oraz wyników badań. Omówiono technikę pomiarową oraz przeanalizowano rezultaty pod kątem teorii przepływów przez zbiorniki i reaktory.
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Active dynamic thermography in mammography.
PublicationW artykule przedstawiono zaproponowany numeryczny model termiczny piersi z nowotworem umiejscowionym na różnych głębokościach. Przedstawione są wyniki symulacji modelu dla różnych warunków zewnętrznego pobudzenia termicznego powierzchni piersi. Pokazano również wyniki przykładowego badania termograficznego piersi z nowotworem.
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Dynamic thermography in diagnostics of onychomycosis.
PublicationW pracy zaprezentowano wyniki badań grzybicy paznokci przy użyciu termografii dynamicznej. Przedstawione wyniki badań pokazują, że metoda ta może okazać się skuteczna przy określaniu stanu mikrokrążenia w tkance pod paznokciem, co pozwoliłoby określić stopień zaawansowania choroby grzybiczej, a więc także umożliwiałoby ocenę postępów leczenia tej przypadłości.
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Static and dynamic concrete calculations: Breakable aggregates in DEM model
PublicationThe paper deals with the calculations of a 3-point bending beam under static and dynamic loads. The real microstructure was obtained from laboratory tests using micro-tomography images. The quasi-static results were compared directly with experimental data at both macro and micro levels. Subsequently, higher strain rates were applied to investigate dynamic effects. The study focused on the influence of dynamic loading on the macroscopic...