Comparison of Ammonia Emissions from Poultry Houses Based on Diurnal Integration vs. Daily Means of Gas Concentration and Building Ventilation Rate
Quantification of aerial emissions from animal feeding operations (AFOs) requires the knowledge of both concentration of the constituent of interest and the ventilation rate (VR) through the emitting source. Daily emissions can be and are normally determined from diurnal integration of frequent measurements, referred to as the diurnal integration method (DIM), but is resource intensive. Alternatively, daily emission may be more economically estimated from daily means of concentration and VR, referred to as diurnal means method (DMM). In this study, DMM was compared with DIM in determining daily ammonia (NH3) emissions from mechanically ventilated laying-hen, turkey and broiler houses under U.S. production conditions. Results show that deviations in daily NH3 emissions between DMM and DIM methods ranged from as small as < 3% (e.g., for medium age turkey under both cold and warm weather conditions) to as high as 98% (e.g., broiler houses in summer). Deviations were related with coefficient of variation (CV) of VR or NH3 concentration, although prediction of the deviation using CV of VR and/or NH3 concentration alone will likely not produce reliable results. The study suggests that caution must be taken when using DMM to estimate daily NH3 emissions from poultry houses under typical US production conditions.
AMMONIA EMISSIONS FROM U.S. POULTRY HOUSES: PART I – MEASUREMENT SYSTEM AND TECHNIQUES
A multi-state, multi-disciplinary research project is currently underway to quantify aerial ammonia (NH3) emissions from selected US poultry houses with different housing and management schemes. A series of publications will result from this study. This paper highlights the system and techniques used by the participating institutions to continuously measure NH3 and carbon dioxide concentrations and determine building ventilation rate. Specifically, a portable monitoring unit (PMU) has been developed and refined for field measurement and acquisition of NH3 level, CO2 level and building static pressure. Ammonia level is measured with electro-chemical sensors that undergo cyclic purging to avoid sensor saturation. Building ventilation rate is directly measured by calibrating the airflow rates of fans in-situ with a Fan Assessment Numeration System (FANS) device and recording of fans runtime, or indirectly calculated using the CO2 balance method based on the latest metabolic rate information for the modern birds (W-36 laying hens). Comparative tests were conducted between the PMU and a chemiluminescence NH3 analyzer in a field emission laboratory (FEL), and there were no significant differences between the two measurement methods (P=0.33).
Discourse Forms and Processes in Indigenous Lowland South America: An Areal-Typological Perspective
▪ Abstract In indigenous lowland South America there are several discourse forms and processes that are shared by groups of people of distinct genetic linguistic affiliations; this leads us to posit this large region, which we label greater Amazonia, as a discourse area, a concept that parallels the notion of linguistic area. The discourse forms and processes we examine are ceremonial dialogue, dialogical performance, templatic ratifying, echo speech, ceremonial greeting, ritual wailing, evidentiality, speech reporting practices, parallelism, special languages, and shamanistic language use. We hypothesize that in lowland South America, discourse is the matrix for linguistic diffusion, i.e., that linguistic areas emerge within discourse areas. What we propose then is a discourse-centered approach to language change and history, parallel to a discourse-centered approach to language structure and use. Our survey includes a plea for a careful archiving of recorded and written materials dealing with lowland So...