ABSTRACT
Tooth wear is one of the dental abnormalities commonly found in different populations. The objective of this work is to conduct a parametric analysis to evaluate the texture influence on the human dental surface hardness, considered here as the ratio between contact force and contact area, obtained through homogenization procedure. A code was implemented using the statistical package R for parametric analysis. The computational approach consists of three routines: numerical generation of surfaces, based on Pearson system; the second, a script coupled to the Finite Element program Abaqus, for the modelling of the micro-contacts; the third for homogenization and statistical analysis of results. The average curvature of the roughness exerts the greatest influence on the surface hardness. The parameters that most influence the development of contact forces are kurtosis followed by skewness.
Subject(s)
Hardness , Humans , Surface PropertiesABSTRACT
This study presents the operation of a biotrickling filter when treating a monochlorobenzene (MCB) contaminated gaseous emission. Treatment dynamics were characterised by exposing the reactor to various MCB Organic Loads (OL). The use of different growth support materials, namely limestone, sand, ceramic and PVC pall-rings, was investigated. Limestone led to dogging of the reactor due to the accumulation of surface precipitates, but PVC pall-rings allowed for a uniform biofilm growth. The biotrickling filter presented maximum removal efficiency (RE, 95%) under OL regimes of 10 g m(-3)-reactor h(-1). Treatment inhibition was observed when the reactor was exposed to OL of 45 g m(-3)-reactor h(-1), with RE reaching a minimum value (8%) and elimination capacity of 8 g m(-3)-reactor h(-1). The first half of the reactor height was the predominant section for MCB biodegradation and increasing the mineral medium recirculation rate was beneficial for the overall treatment.
