Reducing wheel wear of a motorised metro car on a curved track with a small curve radius

A structural solution was proposed to enable passive control of the wheelsets of a motorised metro car on curved track with a small curve radius. This effect was achieved by varying the stiffness of the guidance of the wheelsets in the horizontal plane of the frame of each bogie on which the wagon body rests. This ensured the required critical speed of the metro wagon when moving on straight track, and allowed for reduced mechanical wheel wear and better steering of the bogies when moving on curved track with a small radius of curvature. Parameters specific to the design of modern metro cars were taken into account. Current knowledge of non-linear lateral dynamics of rail vehicles and the specialist computer programme Vi-Rail were used to perform the calculations involving simulation models

New possibilities to reduce wheel and rail wear in the operation of metro wagons on curved track with small curve radii without considering propulsion and braking systems

This paper analyses the parameters relevant to the operation of underground cars in traffic on straight and curved tracks with small curve radii. Current knowledge of non-linear lateral dynamics of rail vehicles and the specialist computer programme Vi-Rail were used to build models and perform simulation calculations. A solution was proposed to enable passive control of wheelsets with very high guiding stiffnesses, without the need for systems to force the axles of the wheelsets to align radially in a curved track. This effect was achieved by varying the guidance stiffness in the horizontal plane of the frame of each bogie. The adopted course of action offers simplicity of solution, low manufacturing costs, high critical speed on straight track and extended service life of the metro wagons resulting from reduced mechanical wear of wheels and rails. A multi-criteria evaluation was carried out, confirming improved bogie controllability and reduced impact of the metro wagon wheelsets on the curved track. Comparisons were made of the design volumes for metro model wagons with bogies with symmetric and unsymmetric axle-guide stiffness arrangements of the wheelsets

Hydrorafinowany olej roślinny jako potencjalne biopaliwo do zasilania silników o zapłonie samoczynnym

Hydro-treating vegetable oils or animal fats is an alternative process to esterification for the production of biodiesel. Hydro-treated products are also called renewable diesel fuels. Hydro-treated vegetable oils (HVO) do not have the harmful effects of FAME biodiesel such as increased NOₓ emissions, deposit formation, storage stability problems, faster aging of the engine oil or poor cold performance. HVO are straight chain paraffinic hydrocarbons which are free of aromatic hydrocarbons, oxygen and sulphur and have a high cetane number. In the article below, the authors conduct a comprehensive analysis and evaluation of the possibility of running compression-ignition engine on the hydro-treated vegetable oil, which is a second-generation biofuel. On its basis, the information on the assessment of emissions of selected toxic components of exhaust gases and pollutants of the injection system when the engine is powered with this type of fuel, was systematized. The article ends with conclusions from the conducted analyses.Motor Transport ISSN 1731-2795 Volume (65), Issue (1), 2022 DOI: 10.5604/01.3001.0015.8709 Hydrorafinowany olej roślinny jako potencjalne biopaliwo do zasilania silników o zapłonie samoczynnym Mieczysław Sikora [email protected] Instytut Pojazdów i Maszyn Roboczych PW, Zakład Silników Spalinowych Piotr Orliński [email protected] Instytut Pojazdów i Maszyn Roboczych PW, Zakład Silników Spalinowych Jan Matej [email protected] Instytut Pojazdów i Maszyn Roboczych PW, Zakład Pojazdów Szynowych Streszczenie: Hydrorafinacja olejów roślinnych lub tłuszczów zwierzęcych jest procesem alternatywnym do estryfikacji służącej do produkcji biodiesla. Produkty hydrorafinowane nazywane są również odnawialnymi olejami napędowymi. Hydrorafinowane oleje roślinne (HVO) nie mają szkodliwych skutków biodiesla typu FAME, takich jak zwiększona emisja NOₓ, tworzenie się osadów, problemy ze stabilnością przechowywania, szybsze starzenie się oleju silnikowego lub złe właściwości w niskich temperaturach. HVO to prostołańcuchowe węglowodory parafinowe, które są wolne od węglowodorów aromatycznych, tlenu i siarki oraz mają wysoką liczbę cetanową. W poniższym artykule autorzy dokonują kompleksowej analizy i oceny możliwości zasilania silnika o zapłonie samoczynnym hydrorafinowanym olejem roślinnym będącym biopaliwem drugiej generacji. Na jej podstawie usystematyzowano informacje dotyczące oceny emisji wybranych składników toksycznych spalin oraz zanieczyszczeń układu wtryskowego przy zasilaniu silnika tego typu paliwem. Artykuł kończą wnioski z przeprowadzonych analiz

New results on light nuclei, hyperons and hypernuclei from HADES (HADES collaboration)

International audienceIn March 2019 the HADES experiment recorded 14 billion Ag+Ag collisions at √sNN = 2.55 GeV as a part of the FAIR phase-0 physics program. In this contribution, we present and investigate our capabilities to reconstruct and analyze weakly decaying strange hadrons and hypernuclei emerging from these collisions. The focus is put on measuring the mean lifetimes of these particles

Metabolic syndrome is associated with similar long-term prognosis in non-obese and obese patients. An analysis of 45 615 patients from the nationwide LIPIDOGRAM 2004-2015 cohort studies

Aims We aimed to evaluate the association between metabolic syndrome (MetS) and long-term all-cause mortality. Methods The LIPIDOGRAM studies were carried out in the primary care in Poland in 2004, 2006 and 2015. MetS was diagnosed based on the National Cholesterol Education Program, Adult Treatment Panel III (NCEP/ATP III) and Joint Interim Statement (JIS) criteria. The cohort was divided into four groups: non-obese patients without MetS, obese patients without MetS, non-obese patients with MetS and obese patients with MetS. Differences in all-cause mortality was analyzed using Kaplan-Meier and Cox regression analyses. Results 45,615 participants were enrolled (mean age 56.3, standard deviation: 11.8 years; 61.7% female). MetS was diagnosed in 14,202 (31%) by NCEP/ATP III criteria, and 17,216 (37.7%) by JIS criteria. Follow-up was available for 44,620 (97.8%, median duration 15.3 years) patients. MetS was associated with increased mortality risk among the obese (hazard ratio, HR: 1.88 [95% CI, 1.79-1.99] and HR: 1.93 [95% CI 1.82-2.04], according to NCEP/ATP III and JIS criteria, respectively) and non-obese individuals (HR: 2.11 [95% CI 1.85-2.40] and 1.7 [95% CI, 1.56-1.85] according to NCEP/ATP III and JIS criteria respectively). Obese patients without MetS had a higher mortality risk than non-obese patients without MetS (HR: 1.16 [95% CI 1.10-1.23] and HR: 1.22 [95%CI 1.15-1.30], respectively in subgroups with NCEP/ATP III and JIS criteria applied). Conclusions MetS is associated with increased all-cause mortality risk in non-obese and obese patients. In patients without MetS obesity remains significantly associated with mortality. The concept of metabolically healthy obesity should be revised