Ruminant animals produce methane through metabolic processes, with implications for production efficiency and contributions to atmospheric accumulation of greenhouses gases. A Ruminant Emission Measurement System (REMS) was designed, constructed and tested at the Metabolism Unit of the Beef Cattle and Sheep Field Laboratory at the University of Illinois at Urbana-Champaign to quantify these emission rates for varying dietary components. REMS is a hyperbaric positive-pressure ventilated hood-type open-circuit respiration chamber system and measures and compares instantaneous methane concentrations between gas entering and exiting a chamber in order to calculate emission rate produced by beef cattle. A series of pumps, sampling tubes, solenoids, connections and chambers are utilized in the measuring process, and therefore many opportunities for dilution or leakage exist. Quality control is crucial in the application of this system to ensure the reliability of the emissions measurements, and a Quality Assurance Project Plan (QAPP) was developed to ensure consistency and reliability during testing. The QAPP presented in this document includes an introduction to all components within this system, quality control tests for each of those components, and general guidelines on the use and maintenance of the system. The document is arranged in four sections followed by the appendix, arranged in chapters for this thesis. The first chapter provides a general introduction to this document, including a description of a Quality Assurance Project Plan and its implementation. The second chapter gives a general description of the system that was constructed, including all the components that make up this system and their functionality. The components include: the gas sampling multiplexer for switching between and directing gas samples to the analyzer; six orifice meters for measuring and controlling ventilation rates; six individual chambers, in each of which the head of one animal is placed during monitoring; a Heating, Ventilating and Cooling (HVAC) system for maintaining comfortable temperature and humidity inside the chambers; the gas analyzer; and system control software.The third chapter focuses on quality assurance tests that were done in order to validate the performance of each component. One crucial assumption for the system operation is that the chamber and other components do not allow inward leakage to occur, thus a leakage test was conducted on the multiplexer, each chamber and the sampling line. In order to show that the chambers maintain positive pressure during test conditions, an internal pressure map was conducted. A calibration was completed for the orifice meters to ensure reliability of ventilation measurements. A calibration was also completed for the gas analyzer to ensure reliability of gas concentration measurement. A tracer-gas recovery test was conducted to validate the performance of the overall system for measuring generation of gas within each chamber. The fourth chapter covers usage and related topics, including the necessary preparations before a test, physical or remote monitoring during a test and data analysis upon concluding a test. General maintenance issues are also discussed and should be followed closely to ensure the well-being of the equipment and integrity of data collected during experiments.The appendices cover specific instructions on using the system control software, conducting a multiplexer leakage test, calibrating the gas analyzer, conducting a system evaluation test, conducting a system performance test, preparations for experiments and operation of the building ventilation system.
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Quality assurance project plan for a ruminant emission measurement system
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