Henry D. Bowen

Comparison of Temperature Correction Methods for Hot Wire Anemometers

ABSTRACT HOT wire anemometer readings for air velocity and mass flux need to be corrected for temperature whenever the test temperature differs from the calibration temperature. Three correction methods to account for differences between the test and calibration temperatures were compared. Anemometer mass flux data were taken at 23.4°C and 40.0°C. The 40.0°C data was corrected to a predicted mass flux at 23.4°C by using the three methods. The Bremhorst procedure, which linearly related the square of the anemometer voltage to the test temperature, was more accurate than either the method recommended by manufacturers, involving temperature difference only, or another method that included both temperature differences and property temperature dependence. For mass fluxes from 1 to 6 kg/m^s, the percent error of the Bremhorst procedure ranged from —8.8% to 2.7% while the latter two methods ranged between 56.1% and 9.1%. The Bremhorst procedure corrected the 40.0°C data to 23.4°C data with resulting mass fluxes being within the 5% accuracy of the anemometer for mass fluxes of 2 kg/m^s or greater.

Dual Particle-Specie Concept for Improved Electrostatic Deposition Through Space-Charge Field Enhancement

A method is developed for enhancing the space-charge deposition of airborne particulates within electrostatically shielded target systems. Upon uniform dispersion of an active specie of particulate along with an inert specie within the target confines, differential electrical migration velocities can be effected to assure preferential deposition of all particles of the active specie before depletion of the interspersed clouds space-charge field. Theoretical equations provide for judicious selection of relative application volumes and particle radii for the two distinct species. The model shows, for example, that when utilized for agricultural pesticide spraying of the interior regions of plant canopies, all toxic pesticide droplets can be electrostatically deposited prior to a 35-percent depletion of the clouds space-charge field if a) at least 80 percent as much inert spray is dispersed along with the toxic spray, and b) if the toxic-to-inert specie radii ratio is ¿ 5. For this specific example of pesticide application, poor deposition of the remaining inert spray under electric-field depletion conditions would be of neither economic nor ecological consequence. The method is also applicable to numerous industrial uses in which space-charge generates the dominant force field for removal of particulate material out of air or other gas streams (e.g., fugitive dust control, precipitation of air-polluting emissions, resource recovery, etc.).

Hydrodynamic Instability of Charged Pesticide Droplets Settling from Crop-Spraying Aircraft: Theoretical Implications

ABSTRACT LARGE-mass droplets of dia.>300 to 400 jwrn enhance gravitational settling from crop-spraying aircraft, but electrostatic forces prove ineffective in their subsequent control at crop elevation. Theoretical development is presented of a process for in-flight creation of a secondary population of high charge-to-mass droplets amenable to electrostatic deposition within the crop vicinity as based upon Rayleigh hydrodynamic instability of charged liquid spheres.

Integration of a Cogeneration System into a Swine Operation: I. Model Development and System Description

ABSTRACT THE development of a mathematical model simulating the operation of a biogas-fueled, engine-generator cogeneration sytem, a thermal energy storage and utilization system, an anaerobic digester, and the electrical and hot water demands on a farrow-to-fmish swine farm is presented. The components of the model were validated with data collected on the University of Nebraska Energy Integrated Farm. The model was written and presented in context of integrating cogenerator operation into a swine operation. This is the first in a series of two papers detailing the integration of a biogas-fueled cogeneration system into a farmstead.

Simulation of Cotton Radicle Elongation During Emergence

ABSTRACT AN empirical computer simulation model for pre-dicting cotton radicle elongation under either constant or fluctuating conditions of the soil physical environment was developed from a set of experimental constant environment radicle growth data—radicle response for four levels each of temperature, moisture, and impedance. Output is radicle elongation with time.

Thermocouple Sensing of Soil Temperature from a Moving Vehicle

ABSTRACT A bare thermocouple attached to the trailing edge of the shank of a tillage tool by means of a can tilevered steel wire spring in conjunction with a can-cellation compensation network proved to be an effective transducer for precise measurements of soil temperatures at the 2.54 - 15.24 cm (1-6 in.) depths, when moving through the soil at tractor speeds.

The boll weevil (Coleoptera: Curculionidae) feeding process: A simulation model

Abstract A model is presented for predicting boll weevil, Anthonomus grandis Boheman, feeding damage to cotton. The model uses appropriate probability theory based on behavioral components of male and nonreproducing female boll weevils and includes the effects of (1) differential feeding site preferences, (2) previous damage to the sites, and (3) individual insect behavior extended to feeding damage caused by a population of insects. The model is sensitive to both crop and insect parameters. An example of how this model can be used in an insect-crop ecosystem simulation is offered.