Following the massive outbreak of SARS (Severe Acute Respiratory Syndrome) in early 2003, the drainage systems in high-rise residential buildings have become a major concern. Inappropriate drainage ...system design may cause pressure fluctuations and depletion of the water trap seal. In Taiwan, most vertical drainage stack pipes serving medium-height apartment blocks are designed as 2 or more vertical pipe systems. A prediction method to determine the air pressure distribution within the single-stack vertical drainage system with a single discharge has already been established. This paper expands this prediction method to allow the air pressure distribution of the 2-pipe vertical drainage and vent system, which is widely used in Taiwan, to be predicted. Comparisons between the measured data and calculated values reveal that the prediction method can reproduce the negative and positive peak air pressure values within the 2-pipe vertical drainage stack given single point discharge and steady flow conditions. A prediction model based on empirical parameters offers a reference for drainage system designers designing and maintaining water trap functions in buildings. This prediction method can be easily applied to drainage system design.
Berries generally represent the primary food source used by Black Bears (Ursus americanus) during summer and sometimes fall. Our study attempted to identify factors influencing the abundance of these ...critical resources for Black Bears in Quebec. We used data from the ecological inventories of the Ministère de l’Environnement du Québec. Three different study areas were selected, including the Papineau-Labelle Wildlife Reserve (326 sample plots; 24 species), the Laurentides Wildlife Reserve (679 sample plots; 16 species) and the Côte-Nord administrative region (1944 sample plots; 30 species). Each site represented a different bioclimatic domain. Characteristics of the dominant vegetation (density and height), soil texture, and drainage classes (vertical or oblique) were used as analysis factors. In general, height and density of the dominant vegetation had a significant effect on the abundance of berry plants. Berry plants were more abundant in plots where dominant vegetation height and density were low. Soil texture had little effect on the abundance of berry plants, and the influence of drainage varied depending on the region. This study allowed us to determine the optimal sites of berry resources for Black Bears.
Various back-analysis methods have been used to predict soil properties. A genetic algorithm (GA) back-analysis method is proposed to overcome the local convergence problem of the existing methods. ...The applicability of the proposed method is analyzed in comparison with other back-analysis methods. The results indicate that the consolidation properties in a multi-layer soft clay ground can be properly predicted using the GA back-analysis at a relatively early stage in the surcharge process. This allows a reliable estimation of the final settlement during the soil improvement process, and also allows the prediction of the continuous settlement due to the surcharge from the subsequently built structures on the improved ground.
Clogging effects on nonwoven geotextile filters can reduce the drainage capacity of vertical drainage materials installed in clay deposits. The preceding clogging retention improvement can be ...increased if the nonwoven geotextile filter is treated by negative ion material in accordance to the knowledge that fine soil particle is negatively charged material. In this study, column tests were conducted to examine the effects of negative-ion treatment by using various types of ion-treated nonwoven geotextile filters. It was found that the negative ion treatment gave apparent increase of drainage capacity after long time as describe on this paper. Clogging effects of two nonwoven geotextile filters treated by negative ion (10 %; NI-10 and 20 %; NI-20) were compared to non-ion treated one (control) by long term filtration test. Finally, the highest drainage capacity was obtained by NI-20 followed by NI-10.
Experimental study on the heat loss from vertical drainage stack, through which some amount of hot water is drained, is conducted in a laboratory. Effects of some factors, such as total volume and ...flow rate of drained water, pipe length, material of pipe, on the heat loss are investigated. To estimate the heat loss, an analytical model is proposed. It uses the steady falling-film theory and the unsteady thermal conduction equation in pipe wall. It was shown that the heat losses predicted by the simplified analytical model are nearly equal to the experimental ones. A set of numerical experiments using the analytical model is conducted according to design experiment theory. Some significant factors which influence the heat loss are clarified and quantitative effects of each factor on the heat loss are expressed in the form of simple regression equations. These equations are useful to evaluate the energy saving design of drain pipe system. Moreover heat loss from the vertical drainage stack is compared with that from the horizontal drain pipe, which is discussed in the previous paper by the authors. It was shown that the former is greater than the later.
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