Carbon Dioxide Production in Animal Houses: A literature review

This article deals with carbon dioxide production from farm animals; more specifically, it addresses the possibilities of using the measured carbon dioxide concentration in animal houses as basis for estimation of ventilation flow (as the ventilation flow is a key parameter of aerial emissions from animal houses). The investigations include measurements in respiration chambers and in animal houses, mainly for growing pigs and broilers. Over the last decade a fixed carbon dioxide production of 185 litres per hour per heat production unit, hpu (i.e. 1000 W of the total animal heat production at 20 oC) has often been used. The article shows that the carbon dioxide production per hpu increases with increasing respiration quotient. As the respiration quotient increases with body mass for growing animals, the carbon dioxide production per heat production unit also increases with increased body mass. The carbon dioxide production is e.g. less than 185 litres per hour per hpu for weaners and broilers and higher for growing finishing pigs and cows. The analyses show that the measured carbon dioxide production is higher in full scale animal houses than measured in respiration chambers, due to differences in manure handling. In respiration chambers there is none or very limited carbon dioxide contribution from manure; unlike in animal houses, where a certain carbon dioxide contribution from manure handling may be foreseen. Therefore, it is necessary to make a correction of data from respiration chambers, when used in full scale animal buildings as basis for estimation of ventilation flow. Based on the data reviewed in this study, we recommend adding 10% carbon dioxide production to the laboratory based carbon dioxide production for animal houses with slatted or solid floors, provided that indoor manure cellars are emptied regularly in a four weeks interval. Due to a high and variable carbon dioxide production in deep straw litter houses and houses with indoor storage of manure longer than four weeks, we do not recommend to calculate the ventilation flow based on the carbon dioxide concentration for these houses

Carbon Dioxide Production in Animal Houses: A Literature Review

This article deals with carbon dioxide production from farm animals; more specifically, it addresses the possibilities of using the measured carbon dioxide concentration in animal houses as basis for estimation of ventilation flow (as the ventilation flow is a key parameter of aerial emissions from animal houses). The investigations include measurements in respiration chambers and in animal houses, mainly for growing pigs and broilers.Over the last decade a fixed carbon dioxide production of 185 litres per hour per heat production unit, hpu (i.e. 1000 W of the total animal heat production at 20 oC) has often been used. The article shows that the carbon dioxide production per hpu increases with increasing respiration quotient. As the respiration quotient increases with body mass for growing animals, the carbon dioxide production per heat production unit also increases with increased body mass. The carbon dioxide production is e.g. less than 185 litres per hour per hpu for weaners and broilers and higher for growing finishing pigs and cows.The analyses show that the measured carbon dioxide production is higher in full scale animal houses than measured in respiration chambers, due to differences in manure handling. In respiration chambers there is none or very limited carbon dioxide contribution from manure; unlike in animal houses, where a certain carbon dioxide contribution from manure handling may be foreseen. Therefore, it is necessary to make a correction of data from respiration chambers, when used in full scale animal buildings as basis for estimation of ventilation flow. Based on the data reviewed in this study, we recommend adding 10% carbon dioxide production to the laboratory based carbon dioxide production for animal houses with slatted or solid floors, provided that indoor manure cellars are emptied regularly in a four weeks interval. Due to a high and variable carbon dioxide production in deep straw litter houses and houses with indoor storage of manure longer than four weeks, we do not recommend to calculate the ventilation flow based on the carbon dioxide concentration for these houses

Apollo 11 Reloaded: Optimization-based Trajectory Reconstruction

This paper wants to be a tribute to the Apollo 11 mission, that celebrated its 50th anniversary in 2019. By using modern methods based on numerical optimization we reconstruct critical phases of the original mission, and more specifically the ascent of the Saturn V, the translunar injection maneuver that allowed the crew to leave the Earth’s sphere of influence, and the Moon landing sequence, starting from the powered descent initiation. Results were computed by employing pseudospectral methods, and show good agreement with the original post-flight reports released by NASA after the successful completion of the mission

MATECH - Werkstoff- und Technologieentwicklung zum Mikrowellensintern von Hochleistungskeramik Abschlussbericht

Die Mikrowellensintertechnologie verspricht verschiedene Vorteile bei der industriellen Herstellung von Hochleistungskeramiken. Bisherige Erfahrungen lagen nur im Labormassstab vor, da weltweit keine produktionsnahen Mikrowellensinteranlagen verfuegbar waren. Die Entwicklung und Erprobung von Prototypen fuer die Serienproduktion von Hochleistungskeramiken war ein wesentlicher Projektinhalt. Im Falle der untersuchten Mischkeramikwerkstoffe Al_2O_3-Ti(C,N), liess sich keine reproduzierbare Verdichtung erzielen. Die auf die Anwendung als Schneidstoff angepasste Si_3N_4-Werkstoffzusammensetzung laesst sich mit Mikrowellen bis zur geschlossenen Porositaet verdichten. Ein anschliessendes Drucksintern ist in jedem Fall notwendig. Das Mikrowellensintern von AlN im groesseren Massstab hat sich ebenfalls als machbar gezeigt. Die relevanten Werkstoffeigenschaften sind mit den konventionell gesinterten Referenzen vergleichbar. (orig.)Microwave sintering is a promising technology for industrial production of heavy-duty ceramics. So far, only laboratory-scale experience is available, so te project comprised the development and testing of prototypes for serial production. In the case of the investigated mixed ceramics Al_2O_3-Ti(C,N), no reproducible densification was observed, while Si_3N_4 materials could be densified to closed porosity. In any case, subsequent pressure sintering is indispensable. Microwave sintering of AlN was feasible on a large scale. The relevant material characteristics are comparable with conventionally sintered reference materialsSIGLEAvailable from TIB Hannover: DtF QN1(84,43) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Development of a dynamic model to predict PM10 emissions from swine houses

Influences on dust emissions from livestock operations are number, weight, and kind of animals and characteristics of the housing system. Diff erences between facilities cannot be explained solely by mechanistic input variables. Th e objective of this study was to characterize the main input variables for modeling emissions of particulate matter with a mass median diameter 6410 \u3bcm (PM10) from swine facilities using a databased model. Investigations were performed in mechanically ventilated facilities for weaning, growing-fi nishing, and sows in Italy and Germany. Th e measurements included inside and outside concentration of airborne PM10 particles (scatter light photometry), ventilation rate (calibrated measuring fans), indoor air climate at a measuring frequency of 60 s, feeding times, and animal-related data such as weight and animal activity. Dust concentration and emission were simulated using a dynamic transfer function. Th e results indicated that the average PM10 emission rate was infl uenced considerably by housing system. Th e simulation of the PM10 emission rate resulted in a mean percentage error per data set of 21 to 39%, whereas the average simulated and measured emission rate per data set diff ered by about 4 to 19%. High prediction errors occurred especially during situations in which the absolute level and spatial location of the measured activity peaks did not correspond with the measured dust peaks. Further recommendations of the study were to improve continuous and accurate measurements of input variables, such as the activity level in animal houses, and to optimize the amount of measuring days in relation to the model accuracy