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1

Investigation of the mechanism of moisture absorption in colloidal museum materials in order to improve the safety of exhibits and improve the hygiene of museum rooms

Dovhaliuk Volodymyr, Ujma Adam, Chovniuk Yurii

System Safety : Human - Technical Facility - Environment

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2019

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Vol. 1, nr 1

805--809

EN

Moisture sorption is one of the most important destruction factors for colloidal capillary-porous exhibits in museums (painting, clothing etc.), which is dependent on microclimate in museum rooms. The analysis of moisture sorption properties, kinetics of sorption and swelling of textile museum exhibits is carried out. Isotherms of desorption of viscose and woollen yarns and fabrics of different density (and threads of them) are identical. The analysis of the isotherms of fabrics of various fibre cloths and threads of them shows that they all are similar in shape to the curves and have the form typical for leading capillary-porous bodies. The hysteresis loop for almost all tissues is observed throughout the range of relative humidity of the medium. In this work, the characteristics of the hysteresis loop (area, limited by it, length of the loop), which are of informational significance in the description of the processes of isothermal sorption-desorption of the materials mentioned above, are indicated. The research results allow optimizing of microclimate control in museum rooms for elimination of destruction of exhibits, improve the safety of storage and ensure the hygiene of the air indoor environmental.

2

Time of Exploitation and Detergency Properties of Low SAPS Engine Oil

Mamgbi R., Cerny J., Barifaijo E.

Nafta-Gaz

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2013

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R. 69, nr 1

57--65

EN

The work is focused on the verification of the premature deterioration of the detergent and dispersant capabilities and some properties of a new generation of so-called “Low SAPS” motor oils, particularly when operating in extended service intervals mode for diesel and petrol engines. Some European automakers have introduced extended service interval checks to 30.000 km for petrol and up to 50.000 km for diesel engines. Service inspections also involve changing of motor oils. To extend this interval it is necessary to ensure not only good quality motor oil, but also sufficient quality motor oil. The paper described changes in the composition of oils, which occurred with the introduction of EURO IV emission limits, which limited the contents of some elements in the oil. In particular, the phosphorus and sulfur content and the amount of sulphated ash substances, i.e. organometallic compounds. Organic compounds of calcium or magnesium are used as active detergents and reducing their contents can change the detergent properties of oils. Attention was paid to gasoline and diesel engines, mainly German manufacturers, namely Audi and Volkswagen cars, Skoda, Porsche and Toyota. 23 samples (13 from diesel engines and 6 from gasoline engines) of used motor oil 14.000÷33.000 km old flexibly extended drained interval from gasoline and diesel engines were taken from a licensed Prague car repair service and analyzed for the normal parameters of motor oils, such as viscosity, total acid number (TAN), total number base number (TBN) and strong base number (SBN), carbon residue, insoluble impurities in pentane (ISP), blotter drop test, soot content and nitrate plus 4 samples taken from earlier drained intervals of 7600÷15.000 km were analyzed only for a blotter spot test as a comparative standard. The relative change in viscosity at 40oC and 100oC were found to be within the accepted 20÷25% range. The carbon residue did not surpass the upper limit. Gasoline oils were found to contain relatively high amounts of insoluble impurities in pentane as compared to diesel oil. A significant decrease in TBN and a massive increase in TAN was observed. Nitrate contents for gasoline oils were relatively high but well below the upper limit.

PL

Niektórzy europejscy producenci samochodów zwiększyli limity przebiegów pomiędzy przeglądami serwisowymi do 30.000 km dla silników benzynowych i do 50.000 km dla silników Diesla. Zwiększenie limitów przebiegu jest możliwe dzięki podwyższeniu jakości silników, ale wymaga również stosowania wysokiej jakości olejów silnikowych. W artykule przedstawiono zmiany właściwości myjących i dyspergujących nowej generacji niskopopiołowych olejów silnikowych (Low SAPS) w przypadkach długich przebiegów pomiędzy przeglądami. Oleje takie zostały opracowane aby wypełnić restrykcyjne limity wynikające z normy EURO IV, ograniczające udziały związków fosforu, siarki i siarczanów w olejach silnikowych, a także emisję popiołów powstających ze związków metaloorganicznych wapnia lub magnezu, które w olejach są stosowane jako detergenty. Badania prowadzono przy wykorzystaniu silników benzynowych i wysokoprężnych, wyprodukowanych przez firmy Audi, Volkswagen, Skoda, Porsche oraz Toyota. Testowano 23 próbki oleju silnikowych po przebiegu od 15 000 do 33.000 km, które zostały pobrane w firmowych warsztatach samochodowych w Pradze. Kontrolowano zmiany podstawowych parametrów olejów silnikowych, takich jak: lepkość, liczba kwasowa (TAN) i zasadowa (TBN), pozostałość po koksowaniu, stężenie zanieczyszczeń nierozpuszczalnych w pentanie (ISP) oraz zawartość azotanów. Przedstawiono wpływ przebiegu, typu silnika i rodzaju paliwa na zmiany parametrów olejów silnikowych. Największe pogorszenia jakości badanych olejów obserwowano w przypadku silników benzynowych.

3

FDTD analysis of magnetized plasma using an equivalent lumped circuit

Moryc A., Gwarek W.

Journal of Telecommunications and Information Technology

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2005

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nr 2

75-78

EN

The paper describes a new approach to electromagnetic analysis of magnetized plasma using finite difference time domain (FDTD) method. An equivalent lumped circuit describing an FDTD cell filled with plasma is developed and applied in the analysis. Such a method is proved more effective than previously reported methods. The new approach is verified on a canonical example of known analytical solution.