Communications - Scientific Letters of the University of Zilina, 2003 (vol. 5), issue 1
Articles
Assesment of the Impact of Road Traffic on Air Pollution
Daniela Durcanska, Milan Moravcik
Communications - Scientific Letters of the University of Zilina 2003, 5(1):5-15 | DOI: 10.26552/com.C.2003.1.5-15 
The negative impact of traffic on air pollution is a generally known fact. Automobile traffic has a great share in polluting the ground layer of the atmosphere where life develops and this applies especially to emissions, i. e. concentrations of polluting substances being emitted. This is the result of emissions of the main polluting substances produced by automobile traffic (CO - carbon monoxide, NOx - sum of nitrogen oxides and VOC - volatile organic compounds) just above the surface of the earth.The article deals with the influence of automobile traffic on air pollution using the methodology of calculating the volume of generated pollutants applied...
Possibilities of Solution of an Automobile Designing and Operation in Relation to the Environment
Vladimir Hlavna, Rastislav Istenik
Communications - Scientific Letters of the University of Zilina 2003, 5(1):16-25 | DOI: 10.26552/com.C.2003.1.16-25
The impact on the environment caused by operation of automobiles is obvious. Although production of emissions in steady-state operations is more or less successfully solved, unsteady operational modes result in a substantially greater impact on the environment. They are, in particular, an engine start and an automobile start up. The article deals with an analysis of an automobile start up and offers some ways of reducing the impact on the environment during the start up.
The Diesel Fuel Post-Injection into Engine Cylinder as Method of Nox Reduction
Zygmunt Szlachta, Jerzy Cisek
Communications - Scientific Letters of the University of Zilina 2003, 5(1):26-35 | DOI: 10.26552/com.C.2003.1.26-35
The possibilities of limiting the emission of nitrogen oxides in the cylinder of the diesel engine by means of its design and operating parameters are limited. This is why studies of the effectiveness of various methods for NOx reduction in exhaust gases are being undertaken. The method used by the authors involves the utilization of a reducing agent in the form of chemically active hydrocarbons (radicals) from the fuel. In order to obtain partially oxidized and thermally decomposed hydrocarbons, the post-injection of fuel (the injection of an additional portion of fuel) into the diesel engine cylinder during the expansion stroke was implemented. To...
On the Design of Running Gears with Radial Steering Wheel Sets
Oldrich Polach
Communications - Scientific Letters of the University of Zilina 2003, 5(1):36-42 | DOI: 10.26552/com.C.2003.1.36-42
Noise reduction of railway vehicles can be reached by suitable design of their bogies and running gears. Radial steering wheel sets avoid curve squeal. Besides they reduce lateral forces between the wheel and rail and their wear. Design principles for the development of interconnected self-steering wheel sets are introduced on examples of bogies for new articulated vehicles TEŽ and coupled single-axle running gears FEBA for commuter trains NSB Class 72 from Bombardier Transportation Winterthur.
Rail Geometry Analysis (From the Point of View of Wearing in the Operation)
Juraj Gerlici, Tomas Lack
Communications - Scientific Letters of the University of Zilina 2003, 5(1):43-51 | DOI: 10.26552/com.C.2003.1.43-51
Rail geometry analysis is, from the point of view of wearing in the operation, the question of present railway vehicles operation practice. The sequels of negative influence are reflected on the environment state. For the influence rate assessment various methods are used. The wearing state of rail road track is possible to assess in different manners. One of them is the assessment of geometric contact of railway wheel and rail profile. The significant information on the rail track operation state are Delta R function, Tangens Gamma function, effective conicity equivalent conicity, rail profile in the track wear analysis on the ground of real and theoretic...
Transport Policy Related to Road Transport and Sustainable Development
Jozef Gnap, Vladimir Konecny
Communications - Scientific Letters of the University of Zilina 2003, 5(1):52-61 | DOI: 10.26552/com.C.2003.1.52-61
Development in almost all sectors of economy will immediately affect the transport sector. We can say that growth in economy leads automatically to growth in road transport. As a continuous process the road transport industry produces vehicles by new technologies and transport operators finance this section by purchasing new trucks and coaches. There is a continual and tightened process in the road transport legislation, the EU has elaborated conceptions for achieving sustainable development. The state transport policy of the Slovak Republic has to reflect specified results and conceptions, otherwise road transport in the Slovak Republic becomes the...
A Vessel for the Complex Supplying and Wastes Collection of Inland Ships on the Danube
Peter Patek, Jaroslav Borsky, Ivan Kotvan
Communications - Scientific Letters of the University of Zilina 2003, 5(1):62-69 | DOI: 10.26552/com.C.2003.1.62-69
Safe and reliable outgoing/filling of fuels and collection of sewage is important for continuous navigation and environmental protection. The supply vessel on the base of DEIIb barge was designed and built up for these purposes. The investor is the Division Port of Slovak Navigation and Ports Comp. and the builder is H.A.W.K. Comp. in Bratislava. The design and construction are made by the Department of Cars, Ships and Engines, Slovak University of Technology in Bratislava. This contribution demonstrates the project and general arrangement of this vessel.
Utilization of a Pseudo-Stochastic Model of Terrain in Simulation of Vibrations and Snubbing in Road Means of Transport
Blahoslav Harman, Viktor Ferencey
Communications - Scientific Letters of the University of Zilina 2003, 5(1):70-75 | DOI: 10.26552/com.C.2003.1.70-75
Physical and geometrical properties of environment lead to mathematical models of terrain- vehicle interaction. The basic idea of the presented approach is to construct a two - dimensional function whose three-dimensional graph has properties similar to the terrain to be modeled. The idea of the paper is expected to be used in simulation of phenomena connected with impacts of vibrations and snubbing to humans as well as on technological factors.
Quality Assessment of Construction Schedules
Roman Marcinkowski
Communications - Scientific Letters of the University of Zilina 2003, 5(1):76-83 | DOI: 10.26552/com.C.2003.1.76-83
Preparing a schedule is a creative activity. Depending on the planner's imagination and inventiveness different visions of the plan of the same project are created. At this stage it is worth asking which plan is the best, with which scenario for the works execution the effect of the contractor's construction operation is the most desirable. This article presents a formalized method of construction schedules' quality assessment. Its methodical basis is constituted by the model of production scheduling process in a construction execution unit. The assessment of schedules is referred to the absolute scale (in interval 0,1) and is objectified using the...