70 research outputs found
Investigation of the effect of relative humidity on polymers by depth sensing indentation
This article was published in the serial, Journal of Materials Science [© Springer]. The definitive version is available from: http://www.springerlink.com/content/y2g413h8h2l6044m/Stereolithography (SL) resins absorb varying
amounts of moisture dependent on the relative humidities,
which can significantly affect the mechanical properties. In
this work, the influence of relative humidity (RH) on the
mechanical behaviour of an SL resin is investigated using
depth sensing indentation (DSI). The samples were conditioned
by two methods. In the first method, samples were
pre-conditioned at 33.5, 53.8, 75.3 and 84.5% RH using
saturated salt solutions. These preconditioned samples
were tested at 33.5% RH, using a humidity control unit
(HCU) to control RH in the DSI system. In the second
method, samples were conditioned and tested at 33.5, 53.8,
75.3 and 84.5% RH by regulating humidity in the DSI
system using the HCU. Temperature was kept constant at
22.5 C for the conditioning and DSI testing. It was seen
that hardness and modulus decreased with increasing RH
and conditioning time but recovered significantly when
tested after drying. This study demonstrates that RH needs
to be taken into account during the DSI testing of
polymers
The influence of turpentine additive on the ecological parameters of diesel engines
After Lithuania’s accession to the EU it is very important to use a larger amount of renewable fuel. Based on economic and environmental considerations in Lithuania, we are interested in studying the effects of turpentine contents in the blended turpentine-diesel fuel on the engine performance and pollutant emission of compression ignition (CI) engine. Therefore, we used engine test facilities to investigate the effects on the engine performance and pollutant emission of 5 % turpentine in the fuel blend. The tests were carried out in the laboratory on an engine dynamometer of the car Audi 1Z and tractor D21 diesel engines. The experimental results showed that turpentine used in the fuel blend for these diesel engines had a positive influence on the engine performance and exhaust emission
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