An easily implementable signal conditioning circuit for resistive humidity and temperature sensors is presented. It is based on a relaxation oscillator in which both the frequency and the duty-cycle of the square-wave output signal simultaneously carry information from two different types of sensors. The output frequency is linearly related to the resistive unbalance of an active bridge, whereas the duty-cycle is independently controlled by a thermal sensor for controlling temperature error of the humidity sensor (RH). The design, analysis, and experimental characterization of the circuit and its application to a sol-gel thin film porous γ-Al2O3-based humidity sensor and resistance temperature detector are reported. Experimental results confirm the theoretical value predicted. The circuit covering wide resistance measurement range has the potential for remotely monitoring measurement parameters accurately.

Relaxation Oscillator-Based Active Bridge Circuit for Linearly Converting Resistance to Frequency of Resistive Sensor

This work concerns the selection of input-output pairs for improved training of multilayer perceptrons, in the context of approximation of univariate real functions. A criterion for the choice of the number of neurons in the hidden layer is also provided. The main idea is based on the fact that Chebyshev polynomials can provide approximations to bounded functions up to a prescribed tolerance, and, in turn, a polynomial of a certain order can be fitted with a three-layer perceptron with a prescribed number of hidden neurons. The results are applied to a sensor identification example.

Specification of Training Sets and the Number of Hidden Neurons for Multilayer Perceptrons

Analysis of the propagation of measurement error into a computed quantity such as building aerial emissions provides insight into which measurements are most critical and which would have the most impact on the computed quantity if improved. An analysis of different instrument measurements, sampling periods, and sites together comprise an objective means of determining optimal sampling strategies for measurements used to compute aerial emissions from livestock facilities. This article describes the uncertainty analysis for a measurement system used in emissions research, and how it can lead to improvements in measurement system design and implementation to obtain estimates of uncertainty in emissions. The system analyzed was used in a broiler house emission monitoring project that was part of the U.S. EPA Air Consent Agreement. The project required U.S. EPA category I Quality Assurance Project Plan (QAPP) Data Quality Objectives (DQO), which were developed from this uncertainty analysis. Results of the uncertainty analysis suggest that the combined standard uncertainty in ammonia emission from broiler houses in the study was typically less than 6%; it increased with uncertainty in ventilation rate, but decreased as ventilation rate and number of fans running increased. The combined standard uncertainty was quantified for normal measurement conditions (Case 1) and for conditions in which the instrumentation was at the calibration threshold (Case 2). A key conclusion was that, for the measurement system employed in this project, uncertainty in the measurements associated with ventilation rate are the major contributors to emissions rate uncertainty (ranging from 78% to 98.9% of combined standard emission uncertainty).

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1153&context=abe_eng_pubs

Building emissions uncertainty estimates

The flow rate of a conducting liquid is generally measured by an electromagnetic flowmeter, which requires a magnetization coil and a set of sensing electrodes. However, the size and cost of the flow head of this flowmeter generally become very high due to the large size of the magnetizing coil and core material. In this paper, a novel low-cost bridge-type technique of flow measurement of a conducting liquid has been described. In this technique, the lumped-parameter impedances among four electrodes placed at a radial distance apart in a flow-sensing tube form a Wheatstone bridge network. Each of these impedances is a combination of electrode polarization impedances and other impedances. Since the electrode polarization impedances are functions of the flow rate of the conducting liquid and some other parameters, the polarization impedances between two electrodes placed in two locations along the flow path of the conducting liquid may be taken as a measure of the flow rate of the liquid, with the other parameters remaining constant. The nonlinearity of these impedance variations with the flow rate is minimized by the proposed bridge-circuit near-balanced condition. The bridge is excited by a stabilized sinusoidal oscillator and balanced at the no-flow condition of the liquid. The output of the bridge network is converted into a 1- to 5-V dc signal in a signal conditioner circuit. The design aspects, theoretical analysis, and calibration data are presented in this paper. The experimental characteristic of the flowmeter is found to follow the theoretical equation and has good repeatability over the entire operating zone.

A Novel Technique of Flow Measurement for a Conducting Liquid

This report describes the measurement methodologies and results of ammonia (NH3) emissions from two typical Tyson broiler production houses located in western Kentucky. During this study, comprised over 13 months and with six flocks per house, a total of 12 flocks of high quality emissions data were collected. Continuous measurement over a one-year period allowed for delineation of variations in emissions due to seasonal effects, animal growth cycles, and litter conditions. The study was led by Iowa State University (ISU), in collaboration with the University of Kentucky (UK). Data from this study add to and improve the national inventory on ammonia emissions from animal feeding operations (AFOs), especially broiler houses in the southeastern United States. The two broiler houses monitored in this study are designated as Tyson 1-5 or T1-5 and Tyson 3-3 or T3-3 in this report. The monitoring periods reported are 10/07/05 – 11/27/06 for T3-3 and 12/09/05 – 1/09/07 for T1-5. Note that ammonia monitoring began on 10/01/05 in both houses, but no birds were placed in T1-5 until 12/09/05, explaining the different emissions reporting periods. The ammonia emissions reported in this study are based on continuous measurements of ammonia concentration in the inlet and exhaust air and the corresponding mechanical ventilation rate at each broiler house. Two Mobile Air Emissions Monitoring Units (MAEMUs), housing state-of-the-art measurement equipment, calibration accessories, and data acquisition systems, were developed at Iowa State University and used for this monitoring project. Prior to the initiation of monitoring, a series of performance tests were conducted to confirm that the monitoring systems were working as designed and to determine representative locations for air sampling points. An EPA Category 1 Quality Assurance Project Plan (QAPP) – a substantial, 400-page document that outlines the methodologies for the project – was developed by the monitoring team. This Category 1 QAPP was reviewed and approved by EPA. In addition, the project underwent and passed two technical audits: a technical audit by Battelle personnel (contractors hired by EPA) confirming conformance of the project implementation with our QAPP, and an additional technical audit conducted by two nationally prominent agriculture air quality scientists. Disciplines Agriculture | Bioresource and Agricultural Engineering | Poultry or Avian Science Comments The magnitude of ammonia emissions in this study is expressed as annual total on the basis of per bird, per animal unit (AU, = 500 kg or 1100 lb live body weight) or per 1,000 birds marketed, daily mean, daily maximum, flock total, during downtime (i.e., between flocks), and, with a 10% or less uncertainty. These respective values are: a) annual (365-d) emission (including downtime emissions) of 5.1 US tons per house or 77.9 lb/1,000 birds marketed (or 35.4 g/bird marketed); b) 12-flock daily mean (± standard deviation) emission of 30.8 ± 20.0 lb/d-house or 0.91 ± 1.29 lb/AU-d; c) maximum grow-out daily emission of 67.4 lb/ d-house for T1-5 and 78.2 lb/d-house for T3-3; d) mean (± SD) flock total emission of 1545 ± 298 lb/flock; and e) mean (± SD) downtime emission of 19.3 ± 18.2 lb/d-house. Flocks on new litter had a lower emission rate of 27.2 ± 20.6 lb/d-house, as compared to 32.0 ± 19.6 lb/d-house for flocks on built-up litter. Ammonia emission tended to be higher during the warmer weather. Bird age is the predominant influencing factor on ammonia emissions. As such, an empirical equation has been established that relates ammonia emission to This report is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/abe_eng_reports/15 bird age for the monitored broiler houses. Compared with the US EPA ammonia emission factor of 100 g/yrbird (100 g/bird marketed), the magnitude of emission reported from this study is 35.4% of the EPA cited value. The use of an emission factor is not advised for systems such as broiler facilities in which substantial progressive daily variation occurs as birds grow and then are removed repeatedly over a year. The use of emission per 1000 birds marketed more realistically captures the events and allows for emission inventory tracking. Authors Robert T. Burns, Hongwei Xin, Richard S. Gates, Hong Li, Steven J. Hoff, Lara B. Moody, Douglas G. Overhults, and John W. Earnest This report is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/abe_eng_reports/15 Tyson Broiler Ammonia Emission Monitoring Project: Final Report Prepared by Iowa State University and University of Kentucky Key Project Personnel: Robert Burns – Iowa State University Hongwei Xin – Iowa State University Rich Gates – University of Kentucky Hong Li – Iowa State University Steve Hoff – Iowa State University Lara Moody – Iowa State University Doug Overhults – University of Kentucky John Earnest – University of Kentucky Other Project Personnel: Ross Muhlbauer Beth Ramey Tim Shepherd Guillerma Maia Carl Pederson Maria Amaral Zhiping Zhu Anshu Singh Jeremiah Davis Linda Stanton Heidi Anderson Marcello Brauer Brian Zelle Filipe Nascimineto Shafi Rahman Ricardo Vigodeiras Nurun Nahar Jamie Pursewell Lana Meyer Steve Trabue Adam Cook Ken Casey Jay Duncan Date of Report: May 1, 2007 Executive Summary This report describes the measurement methodologies and results of ammonia (NH3) emissions from two typical Tyson broiler production houses located in western Kentucky. During this study, comprised over 13 months and with six flocks per house, a total of 12 flocks of high quality emissions data were collected. Continuous measurement over a one-year period allowed for delineation of variations in emissions due to seasonal effects, animal growth cycles, and litter conditions. The study was led by Iowa State University (ISU), in collaboration with the University of Kentucky (UK). Data from this study add to and improve the national inventory on ammonia emissions from animal feeding operations (AFOs), especially broiler houses in the southeastern United States. The two broiler houses monitored in this study are designated as Tyson 1-5 or T1-5 and Tyson 3-3 or T3-3 in this report. The monitoring periods reported are 10/07/05 – 11/27/06 for T3-3 and 12/09/05 – 1/09/07 for T1-5. Note that ammonia monitoring began on 10/01/05 in both houses, but no birds were placed in T1-5 until 12/09/05, explaining the different emissions reporting periods. The ammonia emissions reported in this study are based on continuous measurements of ammonia concentration in the inlet and exhaust air and the corresponding mechanical ventilation rate at each broiler house. Two Mobile Air Emissions Monitoring Units (MAEMUs), housing state-of-the-art measurement equipment, calibration accessories, and data acquisition systems, were developed at Iowa State University and used for this monitoring project. Prior to the initiation of monitoring, a series of performance tests were conducted to confirm that the monitoring systems were working as designed and to determine representative locations for air sampling points. An EPA Category 1 Quality Assurance Project Plan (QAPP) – a substantial, 400-page document that outlines the methodologies for the project – was developed by the monitoring team. This Category 1 QAPP was reviewed and approved by EPA. In addition, the project underwent and passed two technical audits: a technical audit by Battelle personnel (contractors hired by EPA) confirming conformance of the project implementation with our QAPP, and an additional technical audit conducted by two nationally prominent agriculture air quality scientists. The magnitude of ammonia emissions in this study is expressed as annual total on the basis of per bird, per animal unit (AU, = 500 kg or 1100 lb live body weight) or per 1,000 birds marketed, daily mean, daily maximum, flock total, during downtime (i.e., between flocks), and, with a 10% or less uncertainty. These respective values are: a) annual (365-d) emission (including downtime emissions) of 5.1 US tons per house or 77.9 lb/1,000 birds marketed (or 35.4 g/bird marketed); b) 12-flock daily mean (± standard deviation) emission of 30.8 ± 20.0 lb/d-house or 0.91 ± 1.29 lb/AU-d; c) maximum grow-out daily emission of 67.4 lb/d-house for T1-5 and 78.2 lb/d-house for T3-3; d) mean (± SD) flock total emission of 1545 ± 298 lb/flock; and e) mean (± SD) downtime emission of 19.3 ± 18.2 lb/d-house. Flocks on new litter had a lower emission rate of 27.2 ± 20.6 lb/d-house, as compared to 32.0 ± 19.6 lb/d-house for flocks on built-up litter. Ammonia emission tended to be higher during the warmer weather. Bird age is the predominant influencing factor on ammonia emissions. As such, an empirical equation has been established Tyson Broiler Ammonia Emission Monitoring Project Final Report-Page 1 that relates ammonia emission to bird age for the monitored broiler houses. Compared with the US EPA ammonia emission factor of 100 g/yr-bird (100 g/bird marketed), the magnitude of emission reported from this study is 35.4% of the EPA cited value. The use of an emission factor is not advised for systems such as broiler facilities in which substantial progressive daily variation occurs as birds grow and then are removed repeatedly over a year. The use of emission per 1000 birds marketed more realistically captures the events and allows for emission inventory tracking. Introduction Ammonia emissions from animal feeding operations (AFOs) have been estimated to represent the largest portion of the national ammonia emissions inventory in the United States (Battye et al. 1994). According to the most recent estimates by EPA (2005), broilers constitute 54% of poultry contributions to the U.S. ammonia inventory, and 14.8% of animal agriculture emissions. A comprehensive review by the National Academy of Science (NAS, 2003) regarding air emissions data pertaining to the U.S. AFOs conclud

/pdf/tyson-broiler-ammonia-emission-monitoring-project-final-16czysk77n.pdf

Tyson Broiler Ammonia Emission Monitoring Project: Final Report

http://ieeexplore.ieee.org/iel5/9/24099/01098786.pdf

O. Schuck

Papers

Measurement systems - Application and design [Book Reviews]