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Experimental investigation of loading frequency influence on a strength of asphalt interlayer bonding

Górszczyk Jarosław, Malicki Konrad

Archives of Civil Engineering

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2020

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Vol. 66, nr 1

197--208

EN

The article presents a new approach to testing the strength of asphalt interlayer bonding. Two loading methods were used: static load and cyclic load. Before carrying out static shear strength tests, the interlayer bonding was subjected to cyclic loads with a constant number of cycles but with different frequencies. A number of layered samples with and without geosynthetic interlayers were tested at the set temperature. The comparative analyses allowed to determine the functions approximating the impact of the cyclic load frequency on the static strength of bonding at selected interlayer contact conditions. It was also possible to indicate the frequency of cyclic load at which this parameter has the largest and smallest impact on the static strength of the asphalt interlayer bonding.

PL

W niniejszym artykule przedstawiono wyniki badań wpływu obciążeń cyklicznych o różnych częstotliwościach na wartości statycznej wytrzymałości na ścinanie połączeń międzywarstwowych mieszanek mineralno-asfaltowych. Badaniom poddano próbki warstwowe z połączeniami z geosyntetyczną warstwą pośrednią oraz bez tej warstwy. Badania statyczne przeprowadzono wg metody Leutnera. Częstotliwości obciążeń cyklicznych dobrano w taki sposób, aby nawiązywały do rzeczywistych prędkości ruchu pojazdów samochodowych, a charakterystykę cyklu obciążenia ustalono tak, aby naprężenia styczne w strefie kontaktu odpowiadały naprężeniom stycznym w konstrukcji nawierzchni od obciążenia kołem pojazdu ciężkiego.

2

An experimental study of emission and combustion characteristics of marine diesel engine with fuel injector malfunctions

Kowalski J.

Polish Maritime Research

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2016

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nr 1

77--84

EN

The presented paper shows the results of the laboratory study on the relation between chosen malfunctions of a fuel injector and composition of exhaust gas from the marine engine. The object of research is a marine 3-cylinder, four-stroke, direct injection diesel engine with an intercooler system. The engine was loaded with a generator and supercharged. The generator was electrically connected to the water resistance. The engine operated with a load between 50 kW and 250 kW at a constant speed. The engine load and speed, parameters of the turbocharger, systems of cooling, fuelling, lubricating and air exchange, were measured. Fuel injection and combustion pressures in all cylinders of the engine were also recorded. Exhaust gas composition was recorded by using a electrochemical gas analyzer. Air pressure, temperature and humidity were also recorded. Emission characteristics of the engine were calculated according to ISO 8178 standard regulations. During the study the engine operated at the technical condition recognized as „working properly” and with simulated fuel injector malfunctions. Simulation of malfunctions consisted in the increasing and decreasing of fuel injector static opening pressure, decalibration of fuel injector holes and clogging 2 neighboring of 9 fuel injector holes on one of 3 engine cylinders.

3

Labolatory study on influence of the exhaut gas composition in marine four-stroke diesel engine

Kowalski J.

Journal of Polish CIMAC

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2012

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Vol. 7, no 1

109-116

EN

Presented paper shows results of laboratory tests on the relationship between the throttling of a cross area of an exhaust outlet duct and the composition of exhaust gas from the marine engine. The object of research is a laboratory four-stroke diesel engine, worked with a load from 50kW to 250kW at a constant speed equal 750rpm. During the laboratory tests over 50 parameters were measured of the engine with technical condition recognized as a "working properly" and with simulated the exhaust outlet duct throttling. The simulation consisted of changing the angle of the barrier mounted in the exhaust duct after the turbine, limiting duct cross-sectional area. Results of laboratory research confirm that the best indicator of the throttling of the exhaust gas duct among considered thermodynamic parameters of the engine is pressure of exhaust gas after turbine. Unfortunately mentioned pressure is usually very little and for this reason technically difficult to measure during on-board operation. In the case of measuring the composition of exhaust gas, the throttling of the exhaust gas duct causes visible changes of the oxygen and carbon oxide quantity in the exhaust gas. Other measured gaseous components changed not significant during the throttling of the exhaust gas. The conclusion is that the results of measurements of the composition of exhaust gas may contain valuable diagnostic information about the technical condition of the exhaust gas duct of the marine engine.

4

Laboratory study on influence of air duct throttling on exhaust gas composition in marine four - stroke diesel engine

Kowalski J.

Journal of KONES

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2012

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Vol. 19, No. 1

191-198

EN

Presented paper shows results of laboratory tests on the relationship between the throttling of a cross area of an air intake duct and the composition of exhaust gas from the marine engine. The object of research is a laboratory four-stroke diesel engine, worked with a load from 50kW to 250kW at a constant speed. During the laboratory, tests over 50 parameters were measured of the engine with technical condition recognized as a “working properly” and with a simulated the air intake duct throttling. The simulation consisted of inserting the throttling flanges to the air intake duct before compressor, limiting duct cross-sectional area by 20% and 60% respectively. The results of laboratory research confirm that the effect of the air intake duct throttling on the engine thermodynamic parameters is clearly visible only at considerable throttling. In the case of measuring the composition of exhaust gas, both mole fractions and emissions of gaseous components markedly affected even at low throttling. For example, 20% throttling of the cross section of the air intake duct increase the mole fraction of carbon monoxide in exhaust gas almost 44% during working the engine with load equal to 250kW, and only 10% of the temperature after air cooler. Keep in mind that the temperature after air cooler was an engine parameter, which undergoes the greatest change during the simulation of that malfunction. The conclusion is that the results of measurements of the composition of exhaust gas may contain valuable diagnostic information about the technical condition of the air delivery to the engine system.

5

Badania cech wytrzymałościowych fizycznego modelu gabionu

Surowiecki A., Kozłowski W.

Zeszyty Naukowe Politechniki Rzeszowskiej. Budownictwo i Inżynieria Środowiska

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2011

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z. 58, nr 3/II

87-92

PL

Temat artykułu dotyczy ścian oporowych skonstruowanych z koszy siatkowokamiennych (tzw. gabionów), stosowanych w budownictwie komunikacyjnym w celu zabezpieczenia skarp budowli ziemnych przed osuwiskami. Celem artykułu jest oszacowanie cech wytrzymałościowych gabionu w funkcji parametrów zmiennych związanych z kruszywem wypełniającym kosz i siatkową powłoką kosza. Metoda badawcza jest oparta na podstawie autorskich pomiarów przestrzennego stanu odkształcenia fizycznych modeli gabionów, wykonanych w skali laboratoryjnej.

EN

The subject of the paper refers to gabion retaining walls, as the solution of earthen structures protection of motor roads and railway roads against the slope failures. Were presented the test of estimation of strength characteristics of gabions on the basis of deformations researches of physical gabion models. In particular estimated: the factor of horizontal pressure, the effect of load capacity increase on account of net-basket and the horizontal reinforcing rod and shear strength.

6

Wynik długotrwałego badania współczynnika parcia bocznego w ośrodku rozdrobnionym metodą pomiaru oporów tarcia

Kaczmarek J.

Górnictwo i Geoinżynieria

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2011

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R. 35, z. 2

313-318

PL

Uzasadniono konieczność prowadzenia długotrwałych badań współczynnika parcia bocznego w ośrodku, w którym posadowiono konstrukcję podziemną. Przedstawiono schemat aparatu do badania współczynnika parcia bocznego w gruntach. Omówiono jego konstrukcję oraz sposób wykonywania pomiaru. Zamieszczono wynik badania kąta tarcia wewnętrznego w drobnoziarnistych odpadach przemysłowych. Badanie kąta tarcia wewnętrznego odpadów przeprowadzono w aparacie bezpośredniego ścinania. W oparciu o wyznaczony kąt tarcia wewnętrznego wyznaczono spoczynkowy współczynnik parcia bocznego Ko. Dla badanych odpadów przemysłowych ustalono, metodą pomiaru oporów tarcia, współczynnik parcia bocznego w doświadczeniu długotrwałym, w którym czas badania wynosił 16 miesięcy. Określono początkowy współczynnik parcia bocznego Ko(1), bezpośrednio po obciążeniu próbki, oraz współczynnik parcia bocznego ustalony po szesnastu miesiącach Ko(2), przy stałym w trakcie badania obciążeniu.

EN

In the paper the results of the long-term lab investigation of the at-rest earth pressure coefficient are provided. It has been shown that in the case of the at-rest earth pressure coefficient such approach is necessary. A scheme of the laboratory model is presented. Its construction as well as the measurement method are also discussed. The results concerning the investigation of the internal friction angle are provided - the examination has been performed by the direct shear test. Based on the values of the internal friction angle the earth pressure coefficient Ko has been estimated. For investigated industrial waste the at-rest earth pressure coefficient has been determined by the method of friction resistance measurement. The testing time is sixteen months. The value of the initial coefficient Ko(1) (immediately after loading the sample) as well as the value of coefficient Ko(2) (after 16 months with constant loading) have been estimated.