Investigation of passenger's oscillatory comfort in the bus with respect to the seat position and quality

Doktorska disertacija pod nazivom „Istraživanјe oscilatornog komfora putnika u autobusu sa aspekta položaja i kvaliteta sedišta“ imala je za cilj određivanje oscilatornih karakteristika sedišta u cilju poboljšanja udobnosti korisnika čiji je komfor u pojedinim zonama na platformi autobusa u realnim uslovima eksploatacije smanjen ili ugrožen. Drugi cilj istraživanja je bio provera hipoteze da li promena oscilatornih parametara pojedinih sedišta može da omogući da se postigne ujednačen nivo oscilatornog komfora za sve putnike, bez obzira na njihov položaj na platformi autobusa. U radu je definisan originalni prostorni oscilatorni model međugradskog autobusa IK 301, sa 65 stepeni slobode, koji je poslužio kao konkretna podloga za simulaciono istraživanje "zona jednakog oscilatornog komfora". U oscilatorni model je kao pobuda uvedeno sedam različitih neravnosti kolovoza, snimljenih u realnim uslovima eksploatacije, pri različitim brzinama kretanja mernog vozila (tri loše asfalt-betonske podloge pri brzinama od 64 km/h, 72 km/h i 80 km/h; dobar asfalt-beton i vrlo dobra cement-betonska podloga pri brzini od 80 km/h, kao i dve vremenski smaknute pobude - dobar asfalt-beton i vrlo dobar asfalt-beton pri brzini od 90 km/h). Za svakog korisnika autobusa i za svaku oscilatornu pobudu određen je komfor po metodi za kvantifikovanje vibracija celog tela čoveka, prema međunarodnom standardu ISO 2631 (1997). Uvođenje realnih neravnosti kolovoza omogućilo je da se u obzir uzmu različiti uslovi eksploatacije, što je naročito važno prilikom određivanja oscilatornih zona i pravilnog izbora sedišta kojima treba da se poboljša oscilatorna udobnost u autobusu. Poređenje oscilatornih veličina utvrđenih simulacijom sa kriterijumima koji postavlja međunarodni standard ISO 2631 omogućilo je da se oscilatorni komfor oceni na svakom pojedinačnom sedištu. Pokazalo se da se na platformi vozila mogu definisati "zone približno jednakog komfora". Najkomfornija zona nalazi se u srednjem delu vozila (između osovina), a zona najnižeg komfora se nalazi na zadnjem prepustu, što je potvrđeno rezultatima istraživanja za sve vrste podloga i pri svim razmatranim brzinama kretanja...The aim of doctoral dissertation entitled "Investigation of passengers’ oscillatory comfort in the bus with respect to the seat position and quality" was to define the oscillatory parameters of bus user’s seats with goal to improve ride comfort for users sitting in the platform zones with lower or jeopardized oscillatory comfort, while the bus is running under real operating conditions. The second goal of investigation was to check the hypothesis whether the seats with oscillatory parameters that enable improved vibratory comfort also enable achievement of uniform ride comfort level for all bus occupants, regardless of a seat position on the bus platform. The thesis defines the original spatial oscillatory model of the intercity bus IK 301 with 65 degrees of freedom, used as the basis to determine, by means of simulations, the "almost equal oscillatory comfort zones". The oscillatory model was excited by seven different road roughnesses, registered in service at different speeds (three asphalt-concrete roads in bad conditions recorded at speeds of 64 km/h, 72 km/h and 80 km/h; asphalt-concrete pavement in good condition and cement-concrete pavement in very good condition, both recorded at speed of 80 km/h and two time-staggered excitations - asphalt-concrete in good condition and asphalt-concrete in very good condition, both recorded at speed of 90 km/h). The oscillatory comfort has been determined for each bus occupant and for each excitation signal, according the method for quantifying the whole body vibration prescribed by the international standard ISO 2631 (1997). The introduction of the real excitations into the model allowed the consideration of different bus service conditions, which is especially important for the definition of oscillatory comfort zones and proper choice of seats which should improve the ride comfort. Comparison of oscillatory values defined through simulation and comfort criteria from international standard ISO 2631 (1997) allowed to assess the oscillatory comfort for each particular seat. It is confirmed that the "zones of approximately equal oscillatory comfort" on the vehicle platform can be defined. The most comfortable oscillatory zone is in the middle of the vehicle (between the front and the rear bus axle) and the less comfortable oscillatory zone is on the rear overhang, which is approved by the results of investigation for all road surfaces and for all bus speeds considered..

Prediction of Fuel and Exhaust Emission Costs of Heavy-Duty Vehicles Intended for Gas Transportation

This research focuses on heavy-duty vehicles intended to transport compressed natural gases, i.e., class-2 dangerous goods. The analysis includes heavy-duty vehicles powered by diesel and compressed natural gas and trailers with two body types. The body types used in the research are battery bodies and multiple-element gas containers, with pressure vessels made of composite materials (Type-4) and steel (Type-1). The paper presents the methodological procedure for predicting fuel and exhaust gas emission costs as a function of fuel consumption and transported gas quantities. The effects of different types of bodies and different types of fuel on the transported quantities of gas, vehicle mass utilization, fuel consumption, and exhaust gas emissions are shown. The obtained results show that bodies with Type-4 pressure vessels transport 44% more gas than bodies with Type-1 pressure vessels for one turn. The most cost-effective solution for emission costs is diesel-powered, newer-technology vehicles and Type-4 vessels, requiring EUR 2.82 per ton of gas. Similarly, the most economical choice for fuel costs is compressed natural-gas-powered vehicles with Type-4 bodies and a cost of EUR 19.77 per ton of gas. The research results’ practical application pertains to the selection procedures of vehicles and bodies intended for the transport of gases; they should be considered in the decision-making process, with the aim of attaining a sustainable transport sector with lower costs and less impact on the environment

Analysis of vibration effects on the comfort of intercity bus users by oscillatory model with ten degrees of freedom

The paper analyzes the effects of vibrations on the comfort of intercity bus IK-301 users. Evaluation of vibration effects was carried out according to the criteria set out in the 1997 ISO 2631-1 standard for comfort in public means of transport. Comfort is determined for the space of a driver, passenger in the middle part of the bus and passenger in the rear overhang. Also, the allowable exposure time to vibrations in drivers for the reduced comfort criterion was determined according to the 1978 ISO 2631-1 standard. The bus spatial oscillatory model with ten degrees of freedom was developed for the needs of the analysis. Bus excitation was generated applying the Power Spectral Density of the asphalt-concrete road roughness, as described by the H. Braun model. The allowable vibration exposure time for the driver's body decreases as the spring stiffness of the driver's seat suspension system increases. Simulation was performed using the MATLAB software

Development of Pedestrian Alert System for Use in Electric Vehicles

Modern technology has made electric vehicles more accessible, which is important for the preservation of the environment. Although eco-friendly, from the standpoint of pedestrian safety, they may be baleful. The low levels of noise emitted by electric vehicles at speeds lower than 20 km/h are not sufficient for the pedestrian to become aware of the approaching vehicle based on sound. The topic of this paper is the research of sounds used to warn pedestrians of an incoming electric vehicle, while the goal is to single out the most suitable applicable sound based on an unique self-developed multiparameter methodology (which has been experimentally proved). The paper contains the results of the experiments, both of selecting the most suitable applicable sound and driving-range testing

Analysis of external costs of CO2 emissions for CNG buses in intercity bus service

Within the transport sector, road transport is the largest source of Carbon Dioxide (CO2) emissions. Greater use of vehicles that run on clean alternative fuels can contribute to reduce CO2 emissions. This paper gives special attention to the Compressed Natural Gas (CNG) buses and their comparison with conventional diesel buses, which in countries such as Serbia have a dominant share. Justification of using CNG buses in order to mitigate climate changes is measured by realised annual and average external costs of CO2 emissions. These external costs provide a basis for future use of economic instruments by which negative impacts of transport on the environment can be limited. Research of CO2 emissions and external costs of CO2 emissions in intercity bus service was conducted for three technical-technological concepts of CNG buses in comparison to the two types of conventional diesel buses. Analysis was carried out according to four various scenarios that define different operating conditions on the road network of the Serbia. Obtained results show that CNG buses reduce annual external costs of CO2 emissions by 2…24% compared to conventional diesel buses. Obtained average external costs of CO2 emissions per 100 bus-kms show to what extent their changes are a result of changes of external costs of CO2 emissions and to what extent they are due to changes of operating conditions on the road network

Nafta u sigurnosti energetske opskrbe Hrvatske, budući trendovi i izazovi

Sigurnost opskrbe energijom je jedan od temeljnih ciljeva energetske strategije i politike EU i Republike Hrvatske. Nafta već nekoliko desetljeća ima dominantan udio u energetskoj potrošnji, ali vezano uz strateško opredjeljenje prema klimatskim promjenama i stvaranju niskougljičnog gospodarstva predviđa se da će obnovljivi izvori preuzeti vodeću ulogu u potrošnji energije iza 2030. U radu će se naglasiti važnost nafte u sigurnosti opskrbe energijom Hrvatske, kao i globalni, regionalni i lokalni izazovi koji utječu na sigurnost opskrbe, posebno u tranzicijskom razdoblju dekarbonizacije energetskog sektora. To se primarno odnosi na energetsku i klimatsku politiku, cijene nafte, političke izazove, investicijske prijetnje i prilike, trendove te predviđanja u vezi domaće proizvodnje nafte i naftnih derivate, konkurentnost rafinerija i njihovu modernizacije, kao i sustav obveznih zaliha. Uz to, analiza će obuhvatiti povezanost između naftovodnih sustava Hrvatske i srednjoistočne Europe, s obzirom da mogućnost opskrbe iz više pravaca i izvora predstavlja važan čimbenik sigurnosti opskrbe energijom

REPUBLIKA HRVATSKA U GLOBALNOM SVIJETU NAFTE

Crude oil had a significant influence on the development of both global and Croatian economies. The dynamic growth of production, refining and consumption of crude oil, especially in the 1970s and 1980s was followed by and influenced the significantly higher growth rates of the gross domestic product than those occurred during the last years. Major oil companies were the leaders of the economic development on the global level, while at the local level such leaders are smaller national companies, such as INA Plc. and JANAF Plc. in Croatia. Oil economy developed in turbulent conditions of crude oil market with constant oscillations of crude oil prices, through adjustments to the challenges of implementing new energy policies and measures with regard to climate changes, political crises, and others. Over the last years, a stagnation in crude oil production and consumption has been observed on the global level (4,2 -4,3 billion tons), with a decline being recorded in the developed countries, while higher growth rates have been noticed in China, India and the emerging Asian economies. The beginnings of crude oil (exploration and production) in Croatia dated back to the first half of the 19th century and the end of the 19th century and the beginning of the 20th century (refineries) respectively. The bloom of the Croatian oil economy during the 1970s and 1980s was marked by the crude oil production hitting a record high of 3,1 mil. tons (in 1981) in comparison with the present 613 thousand tons (in 2015) and refining of an all-time high amounting to 9,2 mil. tons (in 1979) as compared to the present 3,5 mil. tons. Croatia contributes with 0,145 pro mille in the global oil production and with 0,862 pro mille in the global oil consumption. Further development and globalisation of oil sector may occur through intensifying the activities on crude oil exploration and production both in Croatia and abroad, but also along with the refineries modernization and increase of share on both domestic and foreign markets. Crude oil transport followed the development of crude oil refining on the domestic market, and especially on the foreign markets of the countries of South-Eastern and Central Europe, with the highest transport of 9,7 mil. tons being achieved in 1990, as compared to 6,2 mil. tons in 2015, with the growth trend being observed owing to increase in transport for foreign refineries and their diversification of crude oil imports from the Omišalj direction. The diversification strategy directed towards storage of crude oil and petroleum products further supports the growth of oil companies and Croatian economy as well. The Croatian oil economy will still remain under the influence of volatile oil market characterised by: price volatility, global trend of reducing the petroleum products consumption, stricter regulations and quality standards, policies and measures for enhancing the security of supply, growing costs and investments together with pressures of reducing prices, growth trend of imports and competitiveness of petroleum products, diversification of supply sources and routes and other. Therefore, continuous adjustments are necessary, as well as prompt responses to challenges and development of new strategies for diversification and growth.Nafta je imala značajni utjecaj na razvoj svjetskog pa tako i hrvatskog gospodarstva. Dinamičan rast proizvodnje, prerade i potrošnje nafte, posebno 1970. tih i 1980. tih godina bio je praćen i utjecao je na znatno veće stope rasta bruto domaćeg proizvoda nego su one posljednjih godina. Velike nafte kompanije bile su nositelji gospodarskog razvoja na svjetskoj razini, a na lokalnoj razini to su manje nacionalne kompanije, kao što su INA d.d. i JANAF d.d. u Hrvatskoj. Naftno gospodarstvo razvijalo se u turbuletnim uvjetima naftnog tržišta uz stalne oscilacije cijena nafte, prilagođavajući se izazovima provedbe novih energetskih politika i mjera u vezi klimatskih promjena, političkim krizama, i dr. Posljednjih godina proizvodnja i potrošnja nafte stagniraju na svjetskoj razini (4,2 -4,3 milijarde tona), pri čemu se u razvijenim državama bilježi pad, a veće stope rasta u Kini, Indiji i rastućim ekonomijama Azije. Počeci nafte (istraživanje i proizvodnja) u Hrvatskoj bili su u prvoj polovici 19. stoljeća, odnosno krajem 19. i početkom 20. stoljeća (rafinerije). Procvat naftnog gospodarstva Hrvatske u 1970. tim i 1980. tim godinama obilježili su rekordna proizvodnja nafte od 3,1 mil. tona (1981.) prema današnjih 613 tisuća tona (2015.) i rekordna prerada od 9,2 mil. tona (1979.) prema današnjih 3,5 mil. tona. Hrvatska sudjeluje s 0,145 promila u svjetskoj proizvodnji nafte i s 0,862 promila u svjetskoj potrošnji nafte. Daljnji razvoj i globalizacija naftnog sektora može se desiti intenziviranjem istraživanja i proizvodnje nafte kako u Hrvatskoj tako i u inozemstvu, ali i uz modernizaciju rafinerija i povećanje udjela na domaćem i inozemnim tržištima. Transport nafte pratio je razvoj prerade nafte na domaćem tržištu, ali posebno na inozemnim tržištima država jugoistočne i srednje Europe, pa je tako najveći transport od 9,7 mil. tona ostvaren u 1990. prema 6,2 mil. tona u 2015. s trendom rasta zbog povećanja transporta za inozemne rafinerije i njihove diverzifikacije uvoza nafte iz pravca Omišlja. Strategija diverzifikacije prema skladištenju nafte i naftnih derivata podržava i dalje rast kako naftnih kompanija tako i hrvatske ekonomije. Naftno gospodarstvo Hrvatske biti će i dalje pod utjecajem promjenjivog naftnog tržišta kojeg obilježava: promjenjivost cijena, globalni trend smanjenja potrošnje derivata, stroža regulativa i standardi kvalitete, politika i mjere za povećanjem sigurnosti opskrbe, rast troškova i investicija uz pritiske smanjenja cijena, trend rasta uvoza i konkurentnosti derivata, diverzifikacija izvora i pravaca opskrbe, i dr. Zbog toga su nužne kontinuirane prilagodbe, brzi odgovori na izazove i razvoj novih strategija diverzifikacije i rasta

Checking the formulation modeling process of industrial mill for different types of grinding bodies

This paper presents checking the formulation modeling process of industrial mill for different types of grinding bodies. It is known that changing the type of drilling bodies realizes various efficiency of grinding the mineral raw materials and/or different grinding fineness. This paper gives a hypothesis on bulk mass (density) of a mill batch as an influential factor to the size of specific grinding capacity of the specific mineral resources. The experiment was carried out in the industrial conditions of grinding when the Damkohler's criteria Daq-d = q-d/n*ps was calculated [1]. Verification of this formulation was done in the industrial conditions, and testing results are present in this paper