Search

Byline: E. LeHuuNho, B. Leitl, M. Schatzmann Air quality is one of the major environmental concerns in cities as it has a direct impact on human health. One of the biggest sources of air pollution is urban traffic. To predict air quality in urban areas, significant effort and considerable funding has been, and is being, spent in developing numerical models for urban dispersion and in obtaining experimental datasets. So far, less effort has been expended on providing formalised procedures and reference data suitable for model validation. At the Meteorological Institute of the University of Hamburg, a project has been started to compile a database of wind-tunnel measurements, which can be used for validation of microscale dispersion models. Laser Doppler Anemometer measurements were made on several configurations of the building arrangements. Mean velocity, as well as the intensity of turbulence and the Reynolds stress, were obtained.

One of the key issues of recent research on the dispersion inside complex urban environments is the ability to predict individual exposure (maximum dosages) of an airborne material which is released continuously from a point source. The present work addresses the question whether the computational fluid dynamics (CFD)–Reynolds-averaged Navier–Stokes (RANS) methodology can be used to predict individual exposure for various exposure times. This is feasible by providing the two RANS concentration moments (mean and variance) and a turbulent time scale to a deterministic model. The whole effort is focused on the prediction of individual exposure inside a complex real urban area. The capabilities of the proposed methodology are validated against wind-tunnel data (CUTE experiment). The present simulations were performed ‘blindly’, i.e. the modeller had limited information for the inlet boundary conditions and the results were kept unknown until the end of the COST Action ES1006. Thus, a high uncertainty of the results was expected. The general performance of the methodology due to this ‘blind’ strategy is good. The validation metrics fulfil the acceptance criteria. The effect of the grid and the turbulence model on the model performance is examined. [ABSTRACT FROM PUBLISHER]

In the framework of the German Atmospheric Research Program AFO-2000 a system of consistent coupled numerical models has been developed. The purpose of the model system is to serve as a tool for the execution of European urban air quality regulations. A consortium with the acronym VALIUM was formed, which consisted of German research institutes, environmental consultancies and an environmental agency. A substantial part of the VALIUM program was devoted to the generation of a set of high quality data for the validation of the numerical model system. The validation data are based on a combination of field studies, tracer experiments and corresponding wind tunnel experiments. The field experiments were carried out inside and around a street canyon in a city district of Hanover/Germany. After a brief introduction to the VALIUM project a summary of the main results will be given. [ABSTRACT FROM AUTHOR]

Focuses on the development of experimental datasets and numerical models for urban dispersion to predict air quality in urban areas. Major source of air pollution; Application of Laser Doppler Anemometer measurements; Mean free stream velocity through a Prandtl-tube/pressure transducer system.

Purpose: To evaluate long-term outcomes of AdVance and AdVanceXP male slings in patients with persistent stress urinary incontinence (SUI) after transurethral resection of the prostate (TURP)., Methods: A total of 18 consecutive patients received AdVance (n=14) or AdVanceXP (n=4) male sling implantation between 2007 and 2013. Continence was determined by pad use, 24-hour pad testing and validated questionnaires (International Consultation on Incontinence Questionnaire Short Form, ICIQ-SF). Quality of life was evaluated by International Quality of Life (IQoL) score. Patient satisfaction was measured with patient's global impression of improvement score. Cure was defined as 0-5 g in the 24-hour pad test. Statistical analysis included Fisher exact and Wilcoxon test (P<0.05)., Results: Follow-up was available for 15 patients who underwent further analysis. After a median follow-up of 70 months (range, 18-83 months), mean daily pad usage was 1.8±2.1 pads (P=0.015 vs. baseline level). Mean IQoL score was 66.4±31.6 (P=0.050 vs. baseline level), and mean ICIQ-SF score was 9.5±6.6 (P=0.077 vs. baseline level). Based on 24-hour pad testing, mean daily urine loss was 31.2±64.5 g (median, 0 g; range, 0-209 g). Cure rate was 46.7%, and cure-and-improved rate was 60.0%. Assessing predictive features for success, better results were found in patients who needed up to 4 pads preoperatively (P=0.041) as well as for patients ≤71 years at the time of implantation (P=0.041)., Conclusions: The findings indicate that AdVance and AdVanceXP implantation can be performed effectively and safely in men suffering from SUI after TURP. However, long-term success rates seem to be lower compared to SUI after radical prostatectomy and patients should be counseled accordingly., Competing Interests: R. M. Bauer declares consultancy work, lectures, and participation in clinical trials for AMS (Minnetonka, MN, USA) and Promedon (Cordoba, Argentina). C. Gozzi is the Co-founder of the AdVance male sling. The remaining authors have nothing to disclose.

The capability to predict short-term maximum individual exposure is very important for several applications including, for example, deliberate/accidental release of hazardous substances, odour fluctuations or material flammability level exceedance. Recently, authors have proposed a simple approach relating maximum individual exposure to parameters such as the fluctuation intensity and the concentration integral time scale. In the first part of this study (Part I), the methodology was validated against field measurements, which are governed by the natural variability of atmospheric boundary conditions. In Part II of this study, an in-depth validation of the approach is performed using reference data recorded under truly stationary and well documented flow conditions. For this reason, a boundary-layer wind-tunnel experiment was used. The experimental dataset includes 196 time-resolved concentration measurements which detect the dispersion from a continuous point source within an urban model of semi-idealized complexity. The data analysis allowed the improvement of an important model parameter. The model performed very well in predicting the maximum individual exposure, presenting a factor of two of observations equal to 95%. For large time intervals, an exponential correction term has been introduced in the model based on the experimental observations. The new model is capable of predicting all time intervals giving an overall factor of two of observations equal to 100%.

A set of parameters is introduced to characterize the dispersion of puff releases based on the measured dosage. These parameters are the dosage, peak concentration, arrival time, peak time, leaving time, ascent time, descent time and duration. Dimensionless numbers for the scaling of the parameters are derived from dimensional analysis. The dimensionless numbers are tested and confirmed based on a statistically representative wind tunnel dataset. The measurements were carried out in a 1:300 scale model of the Central Business District in Oklahoma City. Additionally, the effect of the release duration on the puff parameters is investigated., (Copyright © 2014 Elsevier B.V. All rights reserved.)