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Promet - Traffic&Transportation journal

Accelerating Discoveries in Traffic Science

Accelerating Discoveries in Traffic Science

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Federico Dušman
1996 (Vol 8), Issue 6
The report describes the application of the internationalISO 9000 standards in the engines and vehicles indusuy, thatforms part of the 'hardware induslly'. As opposed to classicalinduslly, engines and vehicles industry tends to computer integratedmanufacturing and is realized on the level of the worldwidecooperative system. The international ISO 9000 standardsmake the basis of the organizational aspect of quality andhave a great influence to the technical aspect of product andproduction quality. These standards presume the existence ofall written documents of the quality system that can be fullycomputerized. The basic phases of application of the standards,the certification procedure of the quality system and organizationsthat carry it out are mentioned. The advantagesand the imperfections of certification are pointed out.

Čedomir Dundović
1996 (Vol 8), Issue 6
The loading efficiency of harbor quayside and mobilecranes affects significantly the time duration a ship has tospend at a quay. Therefore, the dimensions of the quaysideloading equipment have to he detennined precisely on the basis of hypothetical production efficiency or the actual loadingcapacity of the harbor quayside and/or mobile cranes.When determining the theoretical average efficiency it issupposed that all the variable factors are contained within theposition of the starting point of the crane hook path, the positionof a half-loaded ship, mean sea level, and the distance ofthe ship center-line from the end point of the hook path at thequayside.The author studies the possibilities to peiform a more correctevaluation of efficiency of harbor quayside and mobilecranes, using the developed analytical method for calculatingthe time duration of the operating cycle traject01y.The applied method is based on the assumed conditionsand empirically determined factors that define single parametersin the path of the gripping device material point in order tofind out the necesswy simplifications in calculating the efficiencyof harbor loading equipment.

Ivan Smerdu
1996 (Vol 8), Issue 6
The article deals with the benefits of additional brake systems,and especially the potential to increase the travellingspeed without an impact of safety and without additional energysupply. These systems are environmentally friendly, as theydo not cause any hwmful emissions to the environment. Thesystems described are today most widely used and have thebest prospects in the future development.Additional brake systems have fundamentally changed theway of driving, also because the psychophysical condition ofthe driver who is operating a vehicle on such a system, is highlysatisfactory. The benefits gained from additional brake systemsexceed incalculably the purchase cost; it would be recommendableto fit out all motor freight vehicles with these systems.

Nenad Zuber, Ivan Smoljan
1996 (Vol 8), Issue 6
The analytical data on the status of road traffic safety inthe Republic ofCroatia in 1995 as compared to the year1994indicates a slight decrease in the number of injuries and fatalinjuries sustained in road traffic accidents, in the incidence ofaccidents with injuries and incidence of accidents in general,despite the reported increase in motor fuel sales and active integrationof a substantial segment of the road system in the Republicof Croatia.Regardless of the causes of road traffic accidents, relevantfactors of influence, types of road traffic accidents, locations,vehicle structure and technical functioning status, and circumstancesof accidents, it is indisputable that the years of servicei.e. experience (or better, non-experience) of drivers appear tobe of major impact upon the number of accidents. Of 62,120road traffic accidents in 1994, 44.4% of accidents resultingfrom driver error were caused by drivers having up to threeyears of driving experience, making 42.9% of all accidents.This fact is both logical and notorious, applying not only tothe Republic of Croatia but to most European countries. Themethods and activities taken to change these figures (effecttheir decrease) differ.

Josip Zavada
1996 (Vol 8), Issue 6
The paper deals with simulated train runs by application ofa mathematical operation model, aimed at reaching the optimumoperation per the criterion of minimum fuel consumption.The results obtained in the process of simulation indicate thatsubstantial savings of fuel can be reached by completion of optimumrun. The elaboration of operation information is recommendedfor practical application of the obtained results. Theauthor lists the required contents and form( at) of informationto be of use to the operator in the completion of the proposedoperation plan. The paper also deals with the simulation completedfor the series 2061 diesel locomotive in the traction ofpassenger and freight trains on the concrete realistic trackprofile. Furthermore the paper provides the recommendationsfor an all-inclusive traction simulation and application of theresults obtained.

Anton Dolenc, Heinz Waras
1996 (Vol 8), Issue 4-5
Designing technological marketing mix (TM-MIX) in differenttraffic, transport and telecommunication systems has abasic feature of a 'decision-making problem' (DMP ). The paperdiscusses mathematical constructs and procedures applicablein developing TM alternatives and in the choice of the bestcombination (composition) ofTM-mix. Algorithm for solving a'General Choice Problem' is presented. Expert Choice Softwareand other decision-support tools have substantial theoreticalsupport in the denoted concepts, procedures and algorithms.

Josip Stepanić, Željko Cvirin
1996 (Vol 8), Issue 4-5
Wo Treibsto.ffe verbrannt werden, entstehen auch Emissionen.In der aktuellen Situation gehoren also Fahrzeugemissionenzu den Hauptthemen. Die Hauptanteile der Abgasemissionenentstehen bei den heutigen katalytischen Abgasnachbehandlungen wiihrend des Kaltstarts und der Kaltlaufphase,solange der Katalysator seine optimale Betriebstemperaturnoch nicht erreicht hat. Dies gilt besonders fur die HC-Emissionen./m Bemiihen, die Luftqualitiit in den europiiischen Uindemund vor allem in den GrojJstiidten zu verbessern und den Vorgabender Weltgesundheitsorganisation (WHO) anzupassen,entwickelt die Kommission der EU eine Serie von Direktivenzur Senkung der Schadstoffemissionen der Strassenfahrzeuge.Um dieses Ziel zu erreichen, hat die Kommission vor etwa zweiJahren zusammen mit den Verbiinden der europiiischen Automobil-und Mineralolindustrie ein gemeinsames Programm(das 'European Programme on Emissions, Fuels & Engine technologies' EPEFE) aufgestellt. Dieses beinhaltet gemeinsameForschungsprogramme, Abgastests sowie Kosten-Nutzen-Analysen.

Čedomir Ivaković, Jasna Jurum
1996 (Vol 8), Issue 4-5
This paper deals with the model for determining the capacityof a river port. The basic parameters of the model are determinedby the size of the aquatorium and the possibilities of locatingquays in the dock basin as well as their number. Thenumber of quays and the static and dynamic capacity of theport - harbour depend on the sizes of the vessels planned fordocking. The analysis considers the push tows Europe 1 and 2and the Danube barges on the basis ofwhich the length of theoperative coastline is determined which in turn is related to the/,ength of the railway tracks, roads, and cargo depots.

Josip Zavada, Ivan Mavrin
1996 (Vol 8), Issue 4-5
The paper studies the regeneration possibilities of Dieselexhaust particle filters, as well as the resulting problems.The application of exhaust particle filters is more and morerequired, because of the increasingly severe limitations imposedon the exhaust emissions of the Diesel engine vehicles.They are particularly necessary on lorries and buses. The particlestrapped in filters increase the counterpressure in the exhaustgases and reduce the engine performance. The most suitablemethod for perfO!ming regeneration is to bum the combustibleparticles trapped in the filter.The temperature of the Diesel engine exhaust gases in thementioned vehicles is not high enough to ignite the particles.To reach the temperatures higher than 550°C, certain measureshave to be undertaken. There are efficient measures outsidethe engine or their combination with measures within theengine.The paper deals especially with measures undertaken outsidethe engine, such as heating the filter using a burner, electricheater or microwave energy, use of fuel additives or applicationof a catalyser.

Anton Černaj, Želimir Dobovišek, Breda Kegl
1996 (Vol 8), Issue 4-5
Basic requirements related to fuel injection system of upgradedturbocharged articulated truck diesel engines are listedand discussed. An example of the FIE matching approach toupgrading of a heavy duty diesel engine is presented. The applicationof hollow cam fuel injection pump may offer a furtherextension of its use in order to uprate diesel engine peiformance.

Nada Štrumberger
1996 (Vol 8), Issue 4-5
There are more than 100 million cars driving on the roadsof Europe, and as many as 40 million only in Germany. Theaverage driving life of an automobile is 13 years. In Gemwnyabout 2.8 million cars are discarded annually, and in Europemore than 10 million passenger cars.In taking care of the old cars, the question is whether toseparate the precious metals from the catalytic converters, as itis known that the car manufacturers have had to install catalyticconverters in the cars in the EC countries starting from JS'April 1993, in order to reduce the harmful exhaust emissions.Collecting of catalytic converters and retrieving of preciousmetals has first started in Europe in 1971. By the year 1994 thequota was estimated at about 450 kg of platinum and 90 kg ofrhodium, and these numbers are expected to increase gradually.A car is not a homogeneous thing. By disassembling it, themetal elements reach the foreseen quota of reusability. There isa greater problem with non-metals, one part of which ends upat the dumping place. The car users take out from the old carpartly the propelling fluid and the cars are disassembled intosingle parts that are being sold directly or recycled. Takingcare of cars has not been organized up to now. The owner hadto pay taxes for that, according to the car type.The system of providing for the cars in the future should bea network one. A network system achieves in cooperation withthe existing car owners a regionally demarcated disassemblingnetwork. The network system takes over, apart from networkdistribution, also the future coordi1wtion net and forms a connectingpoint for the car manufacturers and the recycling ofsecondary raw materials.

Rudi Drevenšek, Marko Košir
1996 (Vol 8), Issue 4-5
ELGREGO SYSTEM startet den Dieselmotor bei extremniedriegen Temperaturen, sogar bis -30°C als wi:iren Sie in denTropen bei +30°C.Stellen Sie sich das Starten eines Dieselmotors bei -30°Cvor. Frost, zugefrorene Leitungen, zehjl.Ussiger Treibstoff,schwache Baterie und vor lhnen nnoch viele Kilometer bis zumZiel.In weniger als 10 Minuten erwi:irmt das ELGREGO SYSTEMden Dieseltreibstoff auf ungefi:ihr- 1 C und ermoglicht soden sofortigen Start des Motors.104Das ELGREGO SYSTEM verhindert das Zufrieren vonLeitungen, Verdickung des Treibstoffs oder das Zufrieren vomWasser bei niedrigen Temperaturen so das die Batterie denMotor mit Leichtigkeit starten.LKWs, Busse, Traktoren, Buldoser und andere lndustriemaschinendie Dieseltreibstoff verbrauchen, werden Dank desELGREGO SYSTEM auch bei niedrigen Temperaturen problemlosstarten und fahren.Des ELGREGO SYSTEM garantiert einen minimalenstromverbrauch von nurl3,5 A.M it dem ELGREGO SYSTEM sparen Sie Zeit, Geld, Treibstoffund lhre Nerven, den lhr Motor und Leute werden rechtzeitigmit der Arbeit beginnen.

Miomir Lazović
1996 (Vol 8), Issue 4-5
The contens, activities and practical methods of the programmreliability of the vehicle are showed. The programmcovers all the phases in the development of the vehicle: concept,design, testing, production and documentation. The programmis based on the relevant parameters of reliability andmaintainability of the vehicle which we can use to define'weakly places', colective Loading and there duration. The programm reliability is made on the form of diagramm flowwhere we have defined requirements of the users, flow and thecontens of the programm activities, expected effects, controlpoints, ...

Borivoj Galović, Sanja Steiner
1996 (Vol 8), Issue 4-5
Vectored propulsion is a new concept of aircraft attitudecontrol by engines jet-deflection. Thrust vectoring researchhas become actualized during the last ten years, mainly formilitary application.The carried out experimental projects confirm the effectivenessof the thrust-vectoring systems in both conventionalaircraft attitude control and post-stall maneuverability enhancement.Apart from military aviation, the results of thrust-vectoringresearch are applicable in civil aviation, especially in STOLand VTOL aircraft design.

Josip Stepanić
1996 (Vol 8), Issue 4-5
In the production of motor vehicle assemblies, as well as ofentire motor vehicles, apart from taking into consideration andadopting a whole range of regulations, standards, conditions,etc., it is ve1y important to carry out the designing and productionin such a way as to enable greater uniformity and replaceabilityof elements and assemblies in a possibly greaternumber of other assemblies and entire vehicles.Greatly increased production of motor vehicles in manycountries of the world, together with the total increase in thenumber of produced vehicles, as well as the frequent change ofmake, result in an incredibly large number of items, components,in the production.Standardization and unification of production to typicalsamples would result in huge savings, at the same time providinghigher quality, reliability and life time of the product. Moreeasily applicable and less expensive automation would providegreater productivity. Basically, the product would be technicallyeasier to use, maintain, and overhaul. Less rime and lesseffort would be needed for the qualified staff to be trained inthe maintenance and overhaul operations.

Ivan Mavrić
1996 (Vol 8), Issue 4-5
The article deals with the problem of assessing the optimalvolume and period for the replacement of ship equipment. Theintroduction analyses the character and the volume of technicalmaintenance and the repair of the ship equipment, certainassemblies and elements of that equipment. Possible tasks andvarious ways in which they can be solved are defined. The statisticalmodelling of random processes is particularly stressed.Eventually, the numerical example of statistical modelling oftechnical maintenance and the assessment of the optimal replacementperiod of the ship pump bearing is given.

Joško Rapanić
1996 (Vol 8), Issue 4-5
The objective of all the braking systems fitted in vehicles isto reduce the speed, as well as to keep them at a standstill. Inorder to increase the active road traffic safety, the experts inthe leading vehicle manufacturer companies are trying from day to day to find a more efficient solution of the highest possiblequality. Braking problems, i.e. problems of stopping the vehiclesare closely related to time, forces, momentum, mass andother physical quantities. This is best seen in the braking ofheavy duty vehicles, trucks, buses, where the braking efficacyis questionable due to high inertia forces caused by heavyweight and more recently relatively high speeds. Such vehiclesare fitted with system of brakes that operate on compressed airor combination of pneumatics and hydraulics, since the driverhas not got enough power to achieve appropriate braking effect.However, the biggest problems occur by trucks runningdownhill, when the braking system is operated continuously fora longer period of time. This causes heating and overheating ofthe system elements ('fading'), thus reducing the braking effect.In extreme cases, particularly if the system is poorly maintained,it can eventually fail completely.Because of the mentioned reasons for difficulties in brakingof trucks, such vehicles have been recently fitted with anauxiliary slow-down system. This system is completely independentfromthe main one on the wheels and is used exclusivelyfor slowing down or for maintaining of speed.

Miomir Lazović
1996 (Vol 8), Issue 4-5
In the article is given some acceptable metodology for projectingand designing of complex mechanical systems as like asvehicle, construction and other, ... with consideration of themaintenance and vehicle maintenability. The analysis is orderedon the problem of bilding the structure of product andtheir functional or designing decomose. At the same time it wasdiscused about level of the structure regarding to requirementsto easy maintenance. The modularity structure of a vehicle isthe condition of modern and effectivenes approach to maintenancewith complitly infOimation support.

Sanja Steiner, Borivoj Galović, Stanislav Pavlin
1996 (Vol 8), Issue 4-5
Respecting the requirements for preservation and protectionof the environment, the present day is marked by implementation of legislative regulations in order to reduce the adverseeffects of transport vehicles.The increasingly strict eco-regulations in air traffic areaimed at reducing the aircraft engine emissions and gradualelimination of noise producing aircraft.Apart from the USA, operational restrictions have been announcedalso by other ICAO members, such as the ECACcountries, Australia, Japan and New Zealand.In spite of a good geo-traffic position and the tendency ofintegration into the European and world traffic routes, Croatiahas found itself, due to the process of gaining independence,defending its vital national interests and organization of civilaircraft authorities, lagging behind with the implementation ofthe present international regulations regarding environmentalprotection criteria in aircraft operations.

Mirko Čudina
1996 (Vol 8), Issue 4-5
Among all auxilimy units of the air cooled diesel engine acooling fan is the noisiest. One of the noise generation mechanismsis the blade interaction with the vortices occurring in theradial and axial clearances of the fan due to the pressure differencebetween the pressure and suction side of the rotorblade. This mechanism of noise generation is especially distinctif the fan is operating in a heavily loaded condition, i.e.,at partial flow rate, when the pressure differences are greater._In this paper the effects of radial and axial clearances betweenthe rotor and stator of the fan on the emitted noise and performances of the fan will be presented and discussed. The experimentalresults have shown that the radial and axial clearancehave its optimum with regard to the best value of emittednoise, performances, dimensions and technology of productionof the fan.

Čedomir Ivaković
1996 (Vol 8), Issue 3
The paper analyzes the methodology of determining thesize of containers and their exchangeability in a terminal. Thesize of containers affects the exchangeability as well as the averageusability of capacity and the lack of uniformity in the deliveryof cargo suitable for container transport. These assumptionsdefine the size of the depot, the lengths and widths of theroad and railway tracks and manipulation areas, and also thenumber and size of shipping quays. Apart from these elementsthe static and dynamic capacity of the terminal depend also onthe handling equipment.

Ivan Mavrin
1996 (Vol 8), Issue 3
In this paper the possibility of application of the cylinderdiagnostics on vibrarion basis is given. A new method is defined.It shows advantages in comparison to the other knownmethods. The influence of various pressures in Ihe cylinder andthe influence of engine working cycle on determining of thecylinder wear are analyzed The theoretical assumptions andexperimental results have proved that this method is a newpossibility for defining the tec!VIical state of the cylinder withoutbeing disassembled, especially suitable for the practicalapplication.

Vladimir Zarić
1996 (Vol 8), Issue 3
The armed forces of the Republic of Croatia have beenfrom the very start of the war, imposed by the aggressor andall the time during the war, exposed to many demands and engagementof all human and material resources was required.Military air force has contributed by its sophisticatedmeans (helicopters, aeroplanes, equipment for air monitoringand guiding and air defence) to the success of all the operationsduring the war which resulted in its successful end andthe liberation of the occupied territories.The helicopters and their crews have performed numerouscombat tasks. One of them is fire support of armed helicoptersto the military units on land, against objects on land and in air.The helicopter pilots (crews) have very professionally performedthe given tasks of fire support to the military units onland.The experiences acquired during the war needed to be generalisedand the combat manoeuvres against objects on landand in air in the uncontrolled zone of the Croatian airspaceoperationalised in order to maximally utilise the possibilitiesof the aircraft and to transfer knowledge (the combat techniques)to young pilots and other crew members.This paper verifies such capabilities of the aircraft and thecrew according to war experiences and the tactics for using thearmed helicopters of the western countries (armed forces).

Ivan Mahalec
1996 (Vol 8), Issue 1-2
The paper considers the surge of a spring, retained at oneend and controlled by a cam at the other end. The periodic liftfunction of the cam was approximately replaced by the Fourierpoly nom. The forced displacement amplitudes were determinedfor each harmonic of this poly nom. The theory of forced longitudinal vibrations of a bar with continuously distributed mass,elasticity and dumping was applied to simulate the motion ofspring coils. It was found out that two or more modes may consistconcurrently in the spring. This was obtained by analyzingmathematical formulas and by comparing computed and publishedmeasured results. The line spectrum of the Fourier serieswas introduced as a useful tool for estimating the influence ofthe high order harmonics on the spring surge.

Mladen Begović, Slavko Šarić, Miroslav Mikula
1996 (Vol 8), Issue 1-2
Modelling of traffic processes in telecommunication systemsin the process of the shift of technologies is indispensablefor purposes of planning and designing the extension of capacitiesand monitoring of the existing traffic flows. The paperdeals with the traffic problem in the telecommunication systemin the period of the exchange of technologies, discussing trafficas a random process and expounding the need for modellingtraffic processes by way of servicing models.

Adolf Malić
1996 (Vol 8), Issue 1-2
Paklenica National Park, covering an area of 3.617 ha,( 1.447 acres) belongs to the group of smaller Croatian nationalparks. It is situated on the Southern slopes of Mount Velebit descendingto the lower coast region, near the Adriatic Highwayand the small town of Starigrad-Paklenica. From the NationalPark, it takes approximately 45 km (26 miles) by road to thenearest/own of any size, Zadar. The sea routes from StarigradPaklenicato Rijeka and Zadar; passing through the LowerVelebit Channel (Podvelebitski kanal) and the Pag and the VirPassages (Paski i Virski prolaz), are not used for public transportas regular ferry and ship links. From the East, Paklenica isclosed by the high Velebit ridge running from Rujan to SveloBrdo. Traffic access to the National Park is therefore easiestfrom the low coastal area from the Southern Starigrad-Paklenicasuburb.The main access route to Paklenica National Park today isthe Adriatic Highway, or E-65 road.

Berislav Grozdanić
1996 (Vol 8), Issue 1-2
During the Croatian War the military forces of the RepublicofCroatia were faced both with foreseen and unforeseen demandsregarding successful airspace combat actions, requiringfull engagement of all human and physical resources of theCroatian Military Air Force.Military Air Force, the most sophisticated part of thearmed forces, has contributed to the success of the operationsby acting in and from airspace against ground and sea targets.The supersonic aircraft efficiency in combat action overairspace targets can be increased by acquiring knowledge regardingthe maximal maneuvering capabilities, application ofgraphic-analytic modeling during flight preparations, educationof pilots and other participants in order to maximally exploitthe aricraft capabilites applying the forced turn. Graphicanalyticmethod of preparing the pilot for combat mission isone of the methods used at a higher level of psychological, theoreticaland practical realizations of the next flight conditions.It is applied in order to increase the efficiency of air-combatand to reduce one's own losses.

Ivan Bošnjak
1996 (Vol 8), Issue 1-2
Designing technological marketing mix (TM-MIX) in differenttraffic, transport and telecommunication systems has abasic feature of a 'decision-making problem' (DMP ). The paperdiscusses mathematical constructs and procedures applicablein developing TM alternatives and in the choice of the bestcombination (composition) ofTM-mix. Algorithm for solving a'General Choice Problem' is presented. Expert Choice Softwareand other decision-support tools have substantial theoreticalsupport in the denoted concepts, procedures and algorithms.


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