Risk assessment in a research laboratory during sol–gel synthesis of nano-TiO2

The occupational risks in the nanotechnology research laboratories are an important topic since a great number of researchers are involved in this area. The risk assessment performed by both qualitative and quantitative methods is a necessary step for the management of the occupational risks. Risk assessment could be performed by qualitative methods that gather consensus in the scientific community. It is also possible to use quantitative methods, based in different technics and metrics, as indicative exposure limits are been settled by several institutions. While performing the risk assessment, the information on the materials used is very important and, if it is not updated, it could create a bias in the assessment results. The exposure to TiO2 nanoparticles risk was assessed in a research laboratory using a quantitative exposure method and qualitative risk assessment methods. It was found the results from direct-reading Condensation Particle Counter (CPC) equipment and the CB Nanotool seem to be related and aligned, while the results obtained from the use of the Stoffenmanager Nano seem to indicate a higher risk level.

Rockburst laboratory tests database - Application of data mining techniques

Rockburst is characterized by a violent explosion of a block causing a sudden rupture in the rock and is quite common in deep tunnels. It is critical to understand the phenomenon of rockburst, focusing on the patterns of occurrence so these events can be avoided and/or managed saving costs and possibly lives. The failure mechanism of rockburst needs to be better understood. Laboratory experiments are undergoing at the Laboratory for Geomechanics and Deep Underground Engineering (SKLGDUE) of Beijing and the system is described. A large number of rockburst tests were performed and their information collected, stored in a database and analyzed. Data Mining (DM) techniques were applied to the database in order to develop predictive models for the rockburst maximum stress (σRB) and rockburst risk index (IRB) that need the results of such tests to be determined. With the developed models it is possible to predict these parameters with high accuracy levels using data from the rock mass and specific project.

Organic load of substrata for wastewater treatment constructed wetlands

In Portugal the use of Constructed Wetlands (CW) for wastewater treatment has been increasing. However a number of these facilities need new strategies to achieve better efficiency. Keeping the culms of reeds on the CW beds not always results as desired, but the use of widely available agro-forest wastes, may be suitable as CW support matrix. This study was performed at lab-scale with dried culms of Phragmites and eucalyptus bark maintained in tap water, to assess them as CW substrata. With a 7 days residence time in water, Phragmites culms added a high organic load (about 400 mg L-1 BOD5) to the medium, while the eucalyptus bark added only, about 60 mg L-1 BOD5. However, by lixiviation, the organic load decreased to about 25 mg L-1 BOD5 in 5 weeks. With the organic load reduction of the leachate water, its surface tension increased, approaching the surface tension of tap water.

Characterization of microbial populations in a wastewater treatment plant focusing on Staphylococcus aureus and Pseudomonas aeruginosa

Dissertação de mestrado em Bioengenharia