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Number of results: 295
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Abstract

This paper addresses the problem of road safety regarding barrier placement as relative to the curb. A short summary of existing regulations is presented. Numerical simulations using the explicit finite element system Ls-Dyna are shown. In the analysis, variable distance between the barrier and the curb is assumed. The obtained result reveals that the distance has little impact on the working width of the barrier.

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Authors and Affiliations

K. Wilde
K. Jamroz
D. Burski
M. Budzyński
S. Burzyński
J. Chróścielewski
W. Witkowski
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Abstract

The aim of the presented paper is to show the results of shape optimization of railway polynomial transition curves (TCs) of 5th, 7th, and 9th degrees through the use of the full vehicle model and new criteria of assessement concerning the jerk value. The search for the proper shape of TCs means that in this work, the evaluation of TC properties is based on select quantities and the generation of such a shape through the use of mathematically understood optimization methods. The studies presented have got a character of the numerical tests. For this work, advanced vehicle models describing dynamical track-vehicle and vehicle-passenger interactions as well as optimization methods were exploited. In the software vehicle model of a 2-axle freight car, the track discrete model, non-linear descriptions of wheel-rail contact are applied. This part of the software, the vehicle simulation software, is combined with a library optimization procedure into the final computer program.

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Authors and Affiliations

K. Zboiński
P. Woznica
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Abstract

The Medical Simulation Center at the Medical University of Białystok was created as part of a broader project. Throughout Poland there are 12 such centers, and each with a somewhat different concept. The common denominator is that they help medical, nursing, and obstetrics students test their knowledge and skills in practice. The Medical Simulation Center in Białystok boasts a sizeable set of simulation facilities, including an operating room, ambulance, emergency ward, labor ward, and nurse’s station. The technicians devise scenarios for students to enable them to practice reacting to specific cases. All the facilities are equipped with state-of-the-art audio-video equipment to record lessons for later review and analysis.

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Authors and Affiliations

Jakub Ostałowski
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Abstract

This study aims to design a novel air cleaning facility which conforms to the current situation in China, and moreover can satisfy our demand on air purification under the condition of poor air quality, as well as discuss the development means of a prototype product. Air conditions in the operating room of a hospital were measured as the research subject of this study. First, a suitable turbulence model and boundary conditions were selected and computational fluid dynamics (CFD) software was used to simulate indoor air distribution. The analysis and comparison of the simulation results suggested that increasing the area of air supply outlets and the number of return air inlets would not only increase the area of unidirectional flow region in main flow region, but also avoid an indoor vortex and turbulivity of the operating area. Based on the summary of heat and humidity management methods, the system operation mode and relevant parameter technologies as well as the characteristics of the thermal-humidity load of the operating room were analyzed and compiled. According to the load value and parameters of indoor design obtained after our calculations, the airflow distribution of purifying the air-conditioning system in a clean operating room was designed and checked. The research results suggested that the application of a secondary return air system in the summer could reduce energy consumption and be consistent with the concept of primary humidity control. This study analyzed the feasibility and energy conservation properties of cleaning air-conditioning technology in operating rooms, proposed some solutions to the problem, and performed a feasible simulation, which provides a reference for practical engineering.

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Authors and Affiliations

X.R. Ding
Y.Y. Cino
Y.Y. Chen
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Abstract

A description of direct simulation of crosswind loads caused by critical vortex excitation and the response of the structure to these loads are presented in this paper. Tower-like structures of circular cross-sections are considered. A proposed mathematical model of vortex excitation has been numerically implemented and a selfserving computer program was created for the purpose. This software, cooperating with the FEM system, allows for a simulation of a crosswind load and lateral response in real time, meaning that at each time step of the calculations the load is generated using information regarding displacements seen beforehand. A detailed description of the mathematical model is neglected in this paper, which is focused on numerical simulations. WAWS and AR methods are used in simulations.

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Authors and Affiliations

T. Lipecki
A. Flaga
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Abstract

This study was carried out on the background of Sutong Bridge project based on fracture mechanics, aiming at analyzing the growth mechanism of fatigue cracks of a bridge under the load of vehicles. Stress intensity factor (SIF) can be calculated by various methods. Three steel plates with different kinds of cracks were taken as the samples in this study. With the combination of finite element analysis software ABAQUS and the J integral method, SIF values of the samples were calculated. After that, the extended finite element method in the simulation of fatigue crack growth was introduced, and the simulation of crack growth paths under different external loads was analyzed. At last, we took a partial model from the Sutong Bridge and supposed its two dangerous parts already had fine cracks; then simulative vehicle load was added onto the U-rib to predict crack growth paths using the extended finite element method.

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Authors and Affiliations

H. Zhu
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Abstract

The object of the present study is to investigate the influence of damping uncertainty and statistical correlation on the dynamic response of structures with random damping parameters in the neighbourhood of a resonant frequency. A Non-Linear Statistical model (NLSM) is successfully demonstrated to predict the probabilistic response of an industrial building structure with correlated random damping. A practical computational technique to generate first and second-order sensitivity derivatives is presented and the validity of the predicted statistical moments is checked by traditional Monte Carlo simulation. Simulation results show the effectiveness of the NLSM to estimate uncertainty propagation in structural dynamics. In addition, it is demonstrated that the uncertainty in damping indeed influences the system response with the effects being more pronounced for lightly damped structures, higher variability and higher statistical correlation of damping parameters.

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Authors and Affiliations

B. Tiliouine
B. Chemali
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Abstract

Simulation-based models standing in for the real world are unfettered by any biological, emotional, historical, logical, or practical limitations.

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Authors and Affiliations

Katarzyna Kasia
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Abstract

Prof. Daniel Wójcik from the Nencki Institute of Experimental Biology explains the principles of brain modelling

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Authors and Affiliations

Daniel Wójcik
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Abstract

Dr. Takao Ishikawa from the University of Warsaw talks about why perhaps not all scientists should aim to become professors, and explains what we can learn from yeast proteins.

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Authors and Affiliations

Takao Ishikawa
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Abstract

This article presents a sequential model of the heating-remelting-cooling of steel samples based on the finite element method (FEM) and the smoothed particle hydrodynamics (SPH). The numerical implementation of the developed solution was completed as part of the original DEFFEM 3D package, being developed for over ten years, and is a dedicated tool to aid physical simulations performed with modern Gleeble thermo-mechanical simulators. Using the developed DEFFEM 3D software to aid physical simulations allows the number of costly tests to be minimized, and additional process information to be obtained, e.g. achieved local cooling rates at any point in the sample tested volume, or characteristics of temperature changes. The study was complemented by examples of simulation and experimental test results, indicating that the adopted model assumptions were correct. The developed solution is the basis for the development of DEFFEM 3D software aimed at developing a comprehensive numerical model allows the simulation of deformation of steel in semi solid state.

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Authors and Affiliations

M. Hojny
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Abstract

The hulls of naval ships are exposed to forces and moments coming from internal and external sources. Usually, these are interactions that can be described mathematically by harmonic and polyharmonic functions. The shock of UNDEX type (underwater explosion) works completely differently and its time waveform is difficult to describe with mathematical functions as pressure vs. time. The paper presents a simplification of physical and mathematical models of 1-D kickoff pressure whose aim is performance the simulation of the external force of the detonation wave. The proposed models were verified and tuned on naval, sea trials. The main goals of the proposed models are to perform simulation calculations of the detonation pressure for different explosion charge weights from different distances of the UNDEX epicentre for the design process of machine foundation. The effects of pressure are transformed as impulses exposed on shock absorber mounted at light shock machine.

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Authors and Affiliations

Andrzej Grządziela
Agata Załęska-Fornal
Marcin Kluczyk
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Abstract

Antarctica is a land of surprises. How low are the lowest temperatures ever recorded there? Is there life at –50°C? Is there anywhere on the continent tourists can actually enjoy swimming?

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Authors and Affiliations

Stanisław Rakusa-Suszczewski
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Abstract

This paper provides an analysis of the evacuation process in a road tunnel in the event of a fire, using the example of the tunnel under the Luboń Mały mountain currently being constructed on Expressway S7’s Lubień – Rabka-Zdrój section. As fires are the largest and most dangerous events occurring in road tunnels, it is important to predict the evacuation process as early as at the design stage. The study described here used numerical modelling to simulate evacuation, which made it possible to determine the required safe evacuation time of all tunnel users in a fire. On the basis of the parameters of the tunnel under Luboń Mały, numerical studies were performed for four different fire scenarios, three of which assumed various fire locations with the currently designed two traffic lanes. The fourth variant accounted for the planned extension of the roadway to include three traffic lanes. Eventually, four numerical models were developed involving various fire ignition locations and numbers of potential tunnel users. The values of initial-boundary conditions used in the simulation, such as movement speed during evacuation, shoulder breadth and pre-movement time, were specified on the basis of experimental data for an evacuation performed in smoke conditions in the Emilia tunnel in Laliki. The results lead to the conclusion that if the time of reaching critical conditions in the tunnel is not shorter than 5 minutes 40 seconds for the current design state and 5 minutes 47 seconds for three lanes, the distribution of evacuation exits in the tunnel under Luboń Mały will ensure safe evacuation.
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Bibliography

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[2] A . Voeltzel, A. Dix, A comparative analysis of the Mont Blanc, Tauern and Gotthard tunnel fires. World Road Association (PIARC ) 324, 18-34 (2004).
[3] I . Maevski, Design Fires in Road Tunnels, A synthesis of Highway Practice. New York: Transportation Research Board NCHR P National Cooperative Highway Research Program Synthesis 415. (2011).
[4] British Standard. The application of fire safety engineering principles to fire safety design of buildings. Human factors. Life safety strategies. Occupant evacuation, behaviour and condition, BSI. PD 7974-6:2004.
[5] E . Ronchi, P. Colonna, J. Capote, D. Alvear, N. Berloco, A. Cuesta, The evaluation of different evacuation models for assessing road tunnel safety analyses. Tunnelling and Underground Space Technology 30, 74-84 (2012). doi: 10.1016/j.tust.2012.02.008
[6] E . Ronchi, M. Kinsey, Evacuation models of the future: insights from an online survey of user’s experiences and needs. Advanced Research Workshop – Evacuation and Human Behaviour in Emergency Situations 145-155 (2011).
[7] N. Schmidt-Polończyk. Ocena możliwości stosowania wentylacji wzdłużnej w długich tunelach drogowych. Assessment of the possibility to apply longitudinal ventilation in long road tunnels. PhD thesis, AGH UST (2016).
[8] Road Tunnels: Operational Strategies for Emergency Ventilation. France: PIARC Committee on Road Tunnels (2011).
[9] M . Kinateder, P. Pauli, M. Müller, J. Krieger, F. Heimbecher, I. Rönnau, Human behaviour in severe tunnel accidents: Effects of information and behavioural training. Transportation Research Part F: Traffic Psychology and Behaviour 17, 20-32 (2013). doi: 10.1016/j.trf.2012.09.001
[10] E . Ronchi, K. Fridolf, H. Frantzich, D. Nilsson, A.L. Walter, H. Modig, A tunnel evacuation experiment on movement speed and exit choice in smoke. Fire Safety Journal 97, 126-136 (2018). doi: 10.1016/j.firesaf.2017.06.002
[11] M . Seike, N. Kawabata, M. Hasegawa, Evacuation speed in full-scale darkened tunnel filled with smoke. Fire Safety Journal 91, 901-907, (2017). doi: 10.1016/j.firesaf.2017.04.034
[12] C. Casse, S. Caroly, Analysis of critical incidents in tunnels to improve learning from experience. Safety Science 116, 222-230 (2019), DOI : 10.17632/scrdwnzc7t.1
[13] K . Fridolf, E. Ronchi, D. Nilsson, H. Frantzich, The representation of evacuation movement in smoke-filled underground transportation systems. Tunnelling and Underground Space Technology 90, 28-41 (2019), doi: 10.1016/j. tust.2019.04.016
[14] J. Porzycki, N. Schmidt-Polończyk, J. Wąs, Pedestrian behavior during evacuation from road tunnel in smoke condition – Empirical results. PLOS ONE 13 (8), e0201732 (2019). doi: 10.1371/journal.pone.0201732
[15] I. Donald, D. Canter, Intentionality and fatality during the King’s Cross underground fire. European Journal of Social Psychology 22 (3), 203-218 (1992).
[16] K . Fridolf, D. Nilsson, H. Frantzich, Fire Evacuation in Underground Transportation Systems: A Review of Accidents and Empirical Research. Fire Technology 49 (2), 451-475 (2013). doi: 10.1007/s10694-011-0217-x
[17] Thunderhead Engineering. Pathfinder 2014.2 Verification and Validation (2014).
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[19] P. Liszka, Ocena bezpieczeństwa ewakuacji w tunelu pod Luboniem Małym. Master’s Thesis, AGH University of Science and Technology (2018).
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[22] RABT : Forschungsgesellschaft fur Strassen-and Verkehrswesen, Richtlinien fuer Ausstattung und Betrieb von Strassentunneln (2006).

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Authors and Affiliations

Natalia Schmidt-Polończyk
1
ORCID: ORCID
Zbigniew Burtan
1
ORCID: ORCID
Piotr Liszka
1

  1. AGH University of Science and Technology, Al. A. Mickiewicza 30, 30-059 Krakow, Poland
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Abstract

The irregularity profiles of steel samples after vapour blasting were measured. A correlation analysis of profile parameters was then carried out. As the result, the following parameters were selected: Pq, Pt, PDq, Pp/Pt and Pku. Surface profiles after vapour blasting were modeled. The modeled surfaces were correctly matched to measured surfaces in 78% of all analyzed cases. The vapour blasting experiment was then carried out using an orthogonal selective research plan. The distance between the nozzle and sample d and the pressure of feed system p were input parameters; selected surface texture coefficients were output parameters. As the result of the experiment, regression equations connecting vapour blasting process parameters p and d with selected profile parameters were obtained. Finally, 2D profiles of steel samples were forecasted for various values of vapour blasting parameters. Proper matching accuracy of modeled to measured profiles was assured in 75% of analyzed cases.
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Authors and Affiliations

Paweł Pawlus
Rafał Reizer
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Abstract

This paper proposes a new approach for calculating the impulse response of room acoustics. Impulse response provides unique characterization of any discrete lineartime invariant (LTI) systems. We assume that the room is a linear time-invariant system and the impulse response is calculated simply by sending a Dirac Impulse into the system as input and getting the response from the output. Then, the output of the system is represented as a sum of time-shifted weighted impulse responses. Both mathematical justifications for the proposed method and results from simulation software developed to evaluate the proposed approach are presented in detail.

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Authors and Affiliations

Adil Alpkocak
Malik Sis
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Abstract

The paper deals with calibration of the simulation models of hydraulic part of an irrigation project. Calibrated simulation model can be used in design, reconstruction, enlargement or maintenance of the pressurized irrigation systems. Computer model of the water distribution system is a valuable tool which can assist engineers and planners in analyzing the hydraulic performance of water delivery systems. Calibration of the water distribution model consists in comparison of pressures and flows predicted with observed pressures and flows for known operating conditions (i.e., pump operation, tank levels, pressure-reducing valve settings), and adjustment of the input data for the model to improve agreement between observed and predicted values. In practice, given a set or sets of measured state variables, engineers apply trial and error techniques with their judgment to vary the parameters and accomplish this task. Trial and error techniques are tedious do not guarantee reasonable results. The paper introduces the methodology of determination of calibrated parameters automatically. Described methodology of calibration is based on optimizing procedures using the harmony search approach.

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Authors and Affiliations

Milan Čistý
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Abstract

Optical coherence tomography (OCT) – a kind of optical counterpart of ultrasound imaging – is continually being improved as image contrast boosting techniques are developed.

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Authors and Affiliations

Karol Karnowski
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Abstract

Weather forecasting requires knowledge of the laws of atmospheric movement. Apart from classic fluid mechanics, we must consider the rotational motion of our planet, the differential heating of its surface through the absorption of solar radiation, as well as water evaporation and condensation processes.

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Authors and Affiliations

Lech Łobocki
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Abstract

Prof. Przemysław Perlikowski, a mechanical engineer, and his wife Asst. Prof. Renata Perlikowska, who studies opioid peptides used in medicine, discuss the challenges of research work and life.

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Authors and Affiliations

Przemysław Perlikowski
Renata Perlikowska
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Abstract

We talk to Prof. Stanisław Filipowicz, Vice-President of the Polish Academy of Sciences, about the significance of truth, the role of fiction, the consequences of living in a culture of excess, and the crisis of democracy.

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Authors and Affiliations

Stanisław Filipowicz
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Abstract

They are unfairly regarded as junk protein, but the truth is they have not been properly studied due to a lack of suitable tools. So how much do we really know about non-globular proteins?

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Authors and Affiliations

Aleksandra Gruca
Marcin Grynberg

Abstract

Polish-Belgian relations are not just about economics or joint membership in European institutions. Rather, they are a story of centuries-old friendship between two nations that cherish freedom. This was the leitmotif of a conference held on the occasion of the 100th anniversary of the establishment of diplomatic relations between the two countries. The conference took place at the headquarters of the Belgian Ambassador in Poland on 11 April 2019, with Polish Senator Anna Maria Anders in attendance.

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Abstract

We all face a wide array of different choices every day of our lives. Asst. Prof. Miłosz Kadziński explains how artificial intelligence could be used to help us make decisions.

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Authors and Affiliations

Miłosz Kadziński
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Abstract

Dr. Aleksandra Przegalinska explains why we find humanoid robots so creepy and considers whether watching machines play football is actually fun.

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Authors and Affiliations

Aleksandra Przegalińska

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