Exposure to fine particulate matter in ten night clubs in Athens Greece: studying the effect of ventilation, cigarette smoking and resuspension

The aim of the present work is to study the occupants' exposure to fine particulate concentrations in ten nightclubs (NCs) in Athens, Greece. Measurements of PM1 and PM 2.5 were made in the outdoor and indoor environment of each NC. The average indoorPM1 andPM 2.5 concentrations were found to be 181.77 μgm−3 and 454.08 μg m−3 respectively, while the corresponding outdoor values were 11.04 μg m−3 and 32.19 μg m−3. Ventilation and resuspension rates were estimated through consecutive numerical experiments with an indoor air quality model and were found to be remarkably lower than the minimum values recommended by national standards. The relative effects of the ventilation and smoking on the occupants' exposures were examined using multiple regression techniques. Itwas found that given the low ventilation rates, the effect of smoking as well as the occupancy is of the highest importance. Numerical evaluations showed that if the ventilation rates were at the minimum values set by national standards, then the indoor exposures would be reduced at the 70% of the present exposure values.

Superfast non-linear diffusion: capillary transport in particulate porous media

The migration of liquids in porous media, such as sand, has been commonly considered at high saturation levels with liquid pathways at pore dimensions. In this letter we reveal a low saturation regime observed in our experiments with droplets of extremely low volatility liquids deposited on sand. In this regime the liquid is mostly found within the grain surface roughness and in the capillary bridges formed at the contacts between the grains. The bridges act as variable-volume reservoirs and the flow is driven by the capillary pressure arising at the wetting front according to the roughness length scales. We propose that this migration (spreading) is the result of interplay between the bridge volume adjustment to this pressure distribution and viscous losses of a creeping flow within the roughness. The net macroscopic result is a special case of non-linear diffusion described by a superfast diffusion equation (SFDE) for saturation with distinctive mathematical character. We obtain solutions to a moving boundary problem defined by SFDE that robustly convey a time power law of spreading as seen in our experiments.

Inhalation exposure to particulate matter in rooms with underfloor air distribution

This work investigated the personal exposure to indoor particulate matters using the intake fraction metric and provided a possible way to trace the particle inhaled from an indoor particle source. A turbulence model validated by the particle measurements in a room with underfloor air distribution (UFAD) system was used to predict the indoor particle concentrations. Inhalation intake fraction of indoor particles was defined and evaluated in two rooms equipped with the UFAD, i.e., the experimental room and a small office. According to the exposure characteristics and a typical respiratory rate, the intake fraction was determined in two rooms with a continuous and episodic (human cough) source of particles, respectively. The findings showed that the well-mixing assumption of indoor air failed to give an accurate estimation of inhalation exposure and the average concentration at return outlet or within the overall room could not relate well the intake fraction to the amount of particle emitted from an indoor source.

Best practice in the training, appointment and remuneration of members of dispute boards for large infrastructure projects

This paper reports part of a qualitative study into evolving practice in the implementation of the Dispute Adjudication Board (DAB) construction dispute resolution technique, a variant of the Dispute Review Board (DRB) concept used in the US and Canada. Data was collected through a focus group interview of 20 highly experienced dispute resolution practitioners from engineering and the law. The group was assembled from members of FIDIC-NET with direct experience of project DABs. The part reported here concerns practice and procedure for establishing DABs. The main findings are that: constitution of the DABs is often delayed because of either project owners' ignorance of the DAB process or deterrence by the cost of the DABs; such owners also tend to insist on appointing DAB members from local engineers and lawyers without sufficient understanding of the DAB process; rates of remuneration of DAB members vary widely; the training provision for DAB membership and advocacy skills is inadequate; the process of selecting candidates for DAB membership and negotiating the tripartite agreement between each member and the contractual parties needs to be navigated with great care to avoid raising ethical problems. The research contribution is threefold. First, it highlights the importance of realistic fees for DAB members within a standard framework in achieving timely establishment of a board that works well as a team. Second, it illustrates the use of qualitative focus group interview to study the impact of new contract terms from multiple stakeholder perspectives. Finally, it identifies areas where further research is needed.