The investigation of traffic flow dynamics of road with traffic lights

In this paper, using discrete model of traffic flow the dynamics of traffic flow against traffic lights controlled road section points was analyzed. In the article is determined what is going on with the traffic flows when period of traffic lights switching was chosen. For the results, road points at different distances from traffic light-controlled road points were chosen. The flow, velocity and density dynamics of traffic flows are determined at different points before the traffic lights. Fundamental diagrams to determine the dependence of traffic flow and density are developed

A mathematical model and simulation results of the dynamic system railway vehicle wheel–track with a wheel flat

A mathematical model of the system Railway Vehicle Wheel–Track with a wheel flat of a wheelset has been made. The system Railway Vehicle Wheel–Track has been examined on the vertical plane. The mathematical model of the system Railway Vehicle Wheel–Track has employed linear, nonlinear, elastic and damping discrete elements. Rail dynamics haves been described using the finite element method. The unevenness of the rail and the wheel of the wheelset have been evaluated considering the contact between the rail and the wheel flat of the wheelset. The analysis of dynamic processes taking place in a railway vehicle wheel with the wheel flat moving at speed V = 60 km/h has been accomplished. The results of mathematical modelling of the above introduced dynamic system have been presented along with graphically displayed research findings of the conducted research. Article in English. Dinaminės sistemos „Geležinkelių vagono ratas – kelias“ su rato iščiuoža matematinis modelis ir modeliavimo rezultatai Santrauka Sukurtas sistemos „Geležinkelių vagono ratas – kelias“ su aširačio rato iščiuoža matematinis modelis. Sistema „Geležinkelių vagono ratas – kelias“ nagrinėjama vertikalioje plokštumoje. Sistemos „Geležinkelių vagono ratas – kelias“ matematiniame modelyje yra panaudoti tiesiniai ir netiesiniai tamprieji ir slopinimo diskretiniai elementai. Bėgio dinamika aprašoma baigtinių elementų metodu. Kontakte tarp bėgio ir aširačio rato su iščiuoža įvertinti bėgio ir aširačio rato nelygumai. Atlikta geležinkelio vagono rato su iščiuoža, judančio greičiu V = 60 km/val., dinaminių procesų analizė. Pateikti šios dinaminės sistemos matematinio modeliavimo rezultatai. Tyrimų rezultatai pavaizduoti grafiškai ir pateiktos tyrimų išvados. Reikšminiai žodžiai: rato bėgio kontaktas, dinamika, pagreitis, penetracija, skaitinis metodas

Mathematical modelling of network traffic flow

The article describes mathematical models of traffic flows to initiate different traffic flow processes. Separate elements of traffic flow models are made in a way to be connected together to get a single complex model. A model of straight road with different boundary conditions is presented as a separate part of the network traffic flow model. First testing is conducted in case the final point of the whole modelled traffic line is closed and no output from that point is possible. The second test is performed when a constant value of traffic flow speed and traffic flow rate is entered. Mathematical simulation is carried out and the obtained results are listed. First published online: 27 Oct 201

Simulation of dynamic processes in hydraulic accumulators

The article focuses on pressure pulsations in hydraulic systems, the means reducing them and examines the structure of hydraulic accumulators, including their features and differences. Using the method of characteristics and Fortran software, a dynamic model of a hydraulic system is created. By changing the content of a hydraulic accumulator, the paper analyzes the amplitude of pressure waves, the distance between hydraulic accumulators and the dependency of the pulsations of pressure waves on the aforementioned sizes. First published online: 27 Oct 201

Investigation into the hydrodynamic processes of fitting connections for determining pressure losses of transport hydraulic drive

The article presents the findings of theoretical and experimental research on hydraulic processes occurring in the hydraulic drives of transport machines. The paper analyses the influence of hydrodynamic processes on the flow characteristics of fluid considering different hydraulic fitting connections. The performed analysis is based on numerical simulations using Navier–Stokes equations for the velocity field. The dynamics of fluid flow in the hydraulic system has been investigated taking into account the main parameters like system flow rate in the range of 5 to 100 L/min, the diameter of the pipeline making 1/2” and fitting standards DKOL, ORFS, BSP and JIS. As a result, pressure drop, power losses, resistance and flow coefficients at different fitting connections have been obtained. The article compares the provided results with the findings given employing the calculation method for the standard of equivalent length fitting. To simulate fluid flow, a mesh independence study and turbulence calculations have been performed. Simulation results have been examined conducting physical experiments on measuring pressure losses. Each experimental research includes three measurements of connections bearing in mind each fitting standard

Trolley motion control based on S-shaped velocity profile for quay crane cargo oscillation comparison

Quay cranes are used to move containers from ship to store in minimum time so that the load reaches its destination without payload oscillation. During the operations, containers are suspended by cables and it’s free to swing by motion. This paper investigates the two different velocity profiling techniques used for quay crane control and cargo stabilization. A laboratory scaled model of a crane is used to experimentally research, where the trolley acceleration is used as input, for suppressing the container sway. The residual cargo oscillation problems using different velocity profiles are discussed. Article in English. Krantinės krano vežimėlio judėjimo valdymas taikant S formos greičio profilį siekiant palyginti krantinės krano krovinio svyravimus Santrauka Krantinės kranai yra naudojami konteineriams transportuoti iš laivo į krantą siekiant užtikrinti minimalų krovos laiką taip, kad krovinys pasiektų savo tikslą esant minimaliems svyravimas. Atliekant tokius krovos darbus krantinės kranu konteineris kabo ant lynų, todėl dėl transportavimo judesių gali atsirasti svyravimų. Šiame darbe analizuojami du skirtingi greičio profiliai, naudojami krantinės krano vežimėlio judesiui valdyti ir kroviniui stabili­zuoti. Eksperimentiniams tyrimams buvo panaudotas mažesnio mastelio laboratorinis krantinės krano modelis, kuriame valdomas vežimėlio pagreitis naudojamas konteinerio svyravimams slopinti. Darbe analizuojama išliekamųjų svyravimų problema ir skirtingų greičio valdymo profilių įtaka šiems svyravimams. Reikšminiai žodžiai: konteinerinis kranas, krovimo procesas, konteinerio svyravimai, eksperimentinė analizė, valdymo sistemos, greičio profiliavimas, trapecinis profilis, S formos profilis

Determination of traffic flow parameters in different traffic flow interaction cases

Modelling of straight road section consisting of one traffic line gives the opportunity to simulate “follow the car” system. In general it looks like a line of vehicles, going one after another. Kinetic theory, used in this paper describes traffic flow system as a straight unbroken line with limited flow speed and concentration. Such model also gives the opportunity to derive traffic lines intersections. For example, intersection could be derived like a point with traffic lines coming and outgoing from this point by only changing boundary conditions. Mathematical model is built using characteristic method. First Published Online: 27 Oct 201

New automatic impulse extinguishing device

A simple way to increase the extinguishing water surface area is to atomize water into fine drops. The smaller drops are developed, the better use of water properties can be implemented and less water is consumed in fire fighting. The automatic impulse extinguishing is created. The main aim of the investigation is to develop the approach to investigate the dynamic and hydrodynamic processes in the extinguishing device. The mathematical model of the extinguishing device is presented, where the flow of liquid and gas and the interaction of liquid with the gas are taken into account. The flow of fluids in a hydraulic system is described by a system of equations of a hyperbolic type, which is solved by a characteristics method. An instance of the mathematical simulation of the activity of extinguishing device is shown. First published online: 27 Oct 201

Modelling of internal combustion engines’ emission through the use of traffic flow mathematical models

Road traffic flows on a straight road segment are modelled in this article. The mathematical model of traffic flows has been constructed by using the method of lumped parameters. CO2, CO, CH, NOx, PM regression equations of internal combustion engines’ (ICE) emission has been developed. The accuracy of regression equations is 0.98÷0.99. The article presents assumptions for constructing the mathematical model, description of the mathematical model and gives simulation results. Traffic flow parameters, such as traffic flow concentration and traffic flow speed are presented as modelling results. ICE emission depending on the concentration and traffic flow speed are presented as well

Analysis into the selection of a ballast water treatment system

Today, it is very important to select and install the optimal equipment for the treatment of ballast water in existing ships. Increasing cargo volumes demand for a greater number of ships for transportation and expanded navigation geography as well as result in increased amount of discharged ballast water. Consequently, sea water pollution is increasing and invasive microorganisms appear that the existing flora and fauna are unaccustomed to. In order to protect territorial waters from these invasive species, International Maritime Organization (IMO) requirements have been implemented that regulate the quality parameters of discharged ballast water from ships. This problem has become particularly relevant for operational ships, in which ballast water treatment equipment and technical solutions had not been anticipated in the design stage. This article provides a comparative analysis of the treatment equipment of ballast water and the related technical parameters, in order to distinguish the most important equipment criteria. A Carrier, according to its technical characteristics, was analysed together with the water treatment method for operated bulk. An expert evaluation for the characteristics of the technical equipment was established