Daniel Pieniak

Chosen Aspects of Municipal Transport Operation on the Example of the City of Lublin

Abstract The paper presents some aspects of operation of municipal transport system in the city of Lublin (Poland). Organization of Lublin Municipal Transport Company was described, its efficiency and perspectives of development. Particular attention was paid to the rules of adjustment to the EU requirements, and to the influence of demographic and social factors. Infrastructure of public transport in Lublin was analyzed (busses, trolley‐busses, bus stations, fixed objects and bus stops), as well as configuration of bus and trolley‐bus lines. Some specific proposals were also put forward regarding development solutions: development plan of trolley‐bus traction, plan of inter‐connection bus station, development plan of bus traction, introduction of advanced IT solutions into the public transport management and natural gas (CNG) fuelling of the city busses. Keywords: urban transport, urban transport problems.

RELIABILITY ANALYSIS OF THE SELECTED BRANDS OF CITY BUSES AT MUNICIPAL TRANSPORT COMPANY / PORÓWNAWCZA ANALIZA NIEZAWODNOŚCI AUTOBUSÓW KOMUNIKACJI MIEJSKIEJ

Abstract The purpose of this paper was to present a reliability comparison of city transport buses on the example of Solaris Urbino 12 and Mercedes- Benz 628 Conecto LF at Municipal Transport Company in Lublin. A reliability index for the most failure parts and complex systems for the period of time up to first damage was determined. It has been demonstrated, that during the operation significant reliability differences occur between the buses produced nowadays. Streszczenie Celem pracy było porównanie niezawodności autobusów miejskich na przykładzie marki Solaris Urbino 12 i Mercedes-Benz 628 Conecto LF w Miejskim Przedsiębiorstwie Komunikacyjnym w Lublinie. Wyznaczono wskaźniki niezawodności najbardziej awaryjnych układów i zespołów w zakresie czasu do pierwszego uszkodzenia. Wykazano, że w praktyce eksploatacyjnej występują znaczące różnice niezawodności pomiędzy współcześnie produkowanymi autobusami znanych firm.

Reliability assessment of a truck engine based on measurements of combustion chamber tightness

The article shows an analysis of the reliability of a compression-ignition engine used in a medium duty truck. The criterion for the reliability assessment was the decrease in combustion chamber tightness. The analysis was based on the results of compression pressure tests and leak-down tests conducted during a long-term operation of 5 trucks. Experimental survival functions and then continuous reliability functions, fitted to the empirical ones, were determined along with the failure rate functions.

Preliminary analysis of the availability of the medium firefighting vehicles chassis / Wstępna analiza gotowości podwozi średnich samochodów pożarniczych

Abstract The paper presents analysis of the availability of medium firefighting and rescue vehicles chassis used by State Fire Brigade in Warsaw. For analysis of availability of vehicles chassis the technical availability factor has been used. Additionally, in the paper time to restore of the vehicles chassis regarding causes of unavailability has been presented. In the tests the data obtained from the Decision Support System (DSS) of Warsaw State Fire Brigade were applied. The research included the period from January 2012 to May 2015. Based on the results, it can be statement that the operating mileage is the crucial factor of operating degradation of firefighting vehicles chassis. Streszczenie W artykule przedstawiono analizę gotowości podwozi średnich samochodów ratowniczo-gaśniczych użytkowanych przez Państwową Straż Pożarną na terenie miasta stołecznego Warszawa. Do analizy gotowości podwozi samochodów pożarniczych wykorzystano współczynnik gotowości technicznej. Ponadto w artykule przedstawiono czasy odnowy podwozi samochodów w zależności od przyczyn stanu niezdatności. W badaniach wykorzystano dane pozyskane z Systemu Wspomagania Decyzji ST (SWD-ST) Komendy Miejskiej PSP m. st. Warszawa. Zakres badań obejmował przedział czasu od stycznia 2012 r. do maja 2015 r. Na podstawie wyników badań można stwierdzić, że dominującym czynnikiem degradacji eksploatacyjnej samochodów pożarniczych jest przebieg eksploatacyjny pojazdu.

Comparative study of wear resistance of the composite with microhybrid structure and nanocomposite

Abstract The aim of the study was to compare microhardness and wear resistance of ceramic-polymer composites with micro and nano-hybrid structure. For the studies commercial composites were used, containing filler particles of the same type but different sizes, nano-sized (Filtek Ultimate) and micro-sized (Filtek Z250) composites. Tribological testing was conducted using ball-on-disc micro-tribometer. Vickers testing method was applied for microhardness studies with the use of Futertech FM 700 device. It has been demonstrated that the wear of Filtek Ultimate is almost twice lower in comparison to wear of Filtek Z250 composite. It has been concluded that the use of filler nanoparticles significantly increased wear resistance of the material. Additionally, lack of correlation between material microhardness and wear resistance has been demonstrated.

Study of ceramic-polymer composites reliability based on the bending strength test

Abstract In this paper the reliability assessment of structural reliability of the selected light-cured dental composites based on the biaxial flexural strength test results has been presented. A two-parameter Weibull distribution was applied as a reliability model in order to estimate probability of strength maintenance in the analysed population. Weibull distribution parameters were interpreted as a characteristic material strength (scale parameter) and structural reliability parameter in terms of ability to maintain strength by each of specimen from the general population (shape parameter). 20 composite specimens underwent strength tests, including 2 “flow” type composites and 2 standard composites (with typical filler content). “Flow” type composites were characterized with lower characteristic strength and higher structural reliability comparing to other studied composites.