Abstract

The use of the extract obtained as a leaching of the coconut fiber (Cocos nucifera) as a biostimulant for the remediation of a savanna soil contaminated with heavy oil was evaluated. Through standardized procedures, the main characteristics of the extract, oil and soil were obtained. The soil was contaminated with 100 mL of heavy oil per kilogram. Four experimental units of 1 kg each were established, leaving the first as a pattern without treatment and 3 treated with extract in proportions of 50, 100 and 150 mL, each with 3 replicates distributed at random. The units were left under controlled laboratory conditions and the percentage of oils and fats and the pH were determined every 7 days by means of the EPA 9071b and ASTM D4972 standards, until complying with the Venezuelan standard Decree 2635. It was concluded by means of a Factorial ANOVA analysis, that both the volume of extract applied and the exposure time exert a statistically significant influence on the percentage of oils and fats and the pH with 95% confidence level. All soil units treated with extract reached the limit value established in Decree 2635 at 28 days.

Abstract

Within the paper production process, certain surface properties of the paper web, e.g. smoothness and gloss, are produced or modified by so-called calenders. This paper machine device consists of several rolls, which apply high pressure and temperature on the paper web. Calenders exhibit large widths up to more than 10 m. Therefore, it is challenging to precisely adjust the required mechanical forces in order to apply a defined line load across the entire width of the paper web. By making use of Voith’s Nipco technology, both line load and roll deflection are controlled by multiple pistons which can be individually adjusted. This is achieved by pressure oil injection. The piston works also as a hydrostatic bearing in such a way that a thin lubrication film is formed between the stationary piston head and the rotating roll shell. Additional oil is injected into the roll for cooling purposes. Within this paper we present an industry-related approach to take advantage of present-day Moving Particle Simulation (MPS) methods. Hereto, we used the commercial software Particleworks® for a numerical investigation of the flow phenomena within a calender roll. The focus of our investigation were the churning losses caused by the interaction between the rotating oil and the mounted piston head. For this purpose, simulations of different oil volumes were performed. The results show that the piston head has a clear impact on the flow field. Firstly, the oil is reflected in upstream direction, causing disturbances in the subsequent flow. Secondly, the oil which streams around the piston rod leads to the formation of a Kármán vortex street. Thirdly, a reduction of oil volume results in a reduction of the churning loss.