William F. Wilcke

ESTIMATION OF WEIGHT PERCENTAGE OF SCABBY WHEAT KERNELS USING AN AUTOMATIC MACHINE VISION AND NEURAL NETWORK BASED SYSTEM

In examining the quality of wheat for pricing purposes, or the scab–resistance of wheat as required for breeding research, it is important to rapidly determine the weight percentage of scabby kernels (WPSK). This study involved development of an automatic system to perform such tasks. This system is based on the color features of scabby kernels captured by a machine vision system. The color features were processed to produce numerical values that were correlated to WPSK using a neural network. Schemes were developed to synchronize an automatic sample feeder with image capturing, followed by automatic image processing and neural network computing. Wheat kernels were distributed in a single layer for image capturing, which minimized the random errors caused by overlapping of kernels and eliminated the need to acquire multiple images to represent a single sample when kernels are distributed in multiple overlapping layers. Statistical analysis indicates that the correlation coefficient between estimated WPSK and actual WPSK was 0.96, with a mean absolute error of 1.32% and maximum absolute error of 5.22%. The system could be stabilized through an online color–compensation procedure that dealt with illumination variations.

Overwintering Mortality of Indianmeal Moth (Lepidoptera: Pyralidae) in Southern Minnesota

Abstract Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), has been classified as one of the most cold-tolerant pests of stored grain. In this study, the supercooling point (SCP) of field-collected, cold-acclimated fifth instars was determined as an index of cold hardiness. In addition, mortality of laboratory-reared and field-collected, cold-acclimated fifth instars exposed to −10°C was measured to understand the ability of P. interpunctella to survive winter conditions. Finally, the overwintering mortality of this species in southern Minnesota was measured in grain bins filled with shelled corn. The SCP of field-collected, cold-acclimated fifth instars was approximately −24°C before their release in grain bins. Mortality of laboratory-reared fifth instars exposed to −10°C reached 100% after only 12 h, whereas the same percentage was achieved after 312 h for field-collected, cold-acclimated individuals. Overwintering mortality of P. interpunctella under field conditions reached 100% in all locations inside the grain bins; however, depth within the grain mass, location inside the grain bin, and the duration of exposure to outdoor conditions significantly affected the rate of mortality. A mathematical model for the overwintering mortality of P. interpunctella is proposed as a first step to forecast early season infestations under field conditions.

STRUCTURE–FUNCTION RELATIONSHIPS OF HIGHLY REFINED CELLULOSE

Highly Refined Cellulose (HRC) used in this project was made from fibrous agricultural residues through a patented proprietary process. The structural properties of HRC are of great importance to its applications. The relationships between its structural and functional properties were studied in this research. The lignin, hemicellulose, and cellulose content of HRC were measured using thermogravity analysis. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to identify and characterize the chemical structure of HRC. A Micromeritics ASAP 2000 was used to analyze the morphology of HRC, and crystallinity ratio was obtained through X–ray diffraction. The raw material had hemicellulose content ranging from 25% to 35%, while HRC had less than 2% hemicellulose. Lignin content was reduced from 35% of raw materials to 22.3% of HRC. The DRIFTS of HRC indicated that the resultant HRC materials had a structure typical of cellulose. The water retention capacity (WRC) and oil retention capacity (ORC) of HRC were 23.5–40.0 g water per gram sample and 13.7–20.8 g oil per g sample. These values were greater than those for the raw materials. The Langmuir surface area, BET surface area, and pore diameter of HRC were 7 to 11 times, 4 to 7 times, and 1.2 to 1.5 times values for the raw materials, respectively. The linear correlation coefficients between WRC and BET surface area, and between WRC and Langmuir surface area, were 0.93 and 0.96, respectively. Crystallinity ratio (1.5–2.2) was negatively correlated with both BET surface area and Langmuir surface area. The linear correlation coefficient between crystallinity ratio and pore diameter was 0.84. This study provides basic understanding of the properties of HRC and information that can be used to design and control the manufacturing of HRC products.

Ozone-Aided Corn Steeping Process

ABSTRACT The present research evaluated the feasibility of using ozone (O3) to replace sulfur dioxide (SO2) in corn steeping. Traditionally, steep water contains 0.1–0.2% sulfur dioxide to promote starch-protein separation and high starch yields, and to control microbial growth. However, residual SO2 in starch products affects product quality and jeopardizes the “organic products” claims. Also, SO2 discharged to the environment pollutes water and air. Ozone is a strong oxidant and disinfectant with a capability to control the growth of putrefactive microorganisms in steeping systems, and to break down the endosperm protein matrix and, hence, improve starch release. This study demonstrates that an ozone-aided steeping (OAS) process had starch yields as high as conventional SO2 steeping. OAS processes can be conducted at a lower temperature (20°C vs. 50°C) and for shorter times (36 hr vs. 48 hr) than the conventional SO2 processes, suggesting significant energy savings and increased productivity. We have fo...

Mortality of Indianmeal Moth (Lepidoptera: Pyralidae) Populations Under Fluctuating Low Temperatures : Model Development and Validation

Abstract A model for predicting mortality of Indianmeal moth larvae [Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)] under fluctuating low-temperature conditions was developed. The time and temperature combinations required to achieve 100% mortality of field-collected, cold-acclimated P. interpunctella larvae obtained from laboratory mortality experiments were used to develop the mortality model. Accumulation of mortality rate over time was called the cumulative lethality index (CLI). Complete mortality of insect populations would occur when CLI equals 1. Observed mortality of field-collected, cold-acclimated P. interpunctella larvae in five 76.2-T (3,000-bu) shelled corn bins located in Rosemount, MN, during the winters of 2003–2004 and 2004–2005 were used to validate the CLI model (i.e., mortality model). Excellent agreement between predicted and measured time to 100% larval mortality was observed. The CLI model would be useful for developing low-temperature aeration management strategies for controlling overwintering P. interpunctella in grain bins. In addition, this model will be useful when determining if additional control measures will be required as a result of above-seasonal ambient temperatures.

Auger-Stirring Wet and Dry Corn — Airflow Resistance and Bulk Density Effects

ABSTRACT EIGHT tests were carried out to define effects of auger stirring on the airflow resistance and bulk density of wet and dry shelled corn placed in a bin by gravity or by spreader. Stirring decreased bulk density of corn placed with a spreader, but increased or left unchanged the bulk density of gravity-placed corn.

Harvesting, Storing, and Post-Harvest Management of Soybeans

Publisher Summary This chapter describes the systems and procedures for harvesting, drying, handling, and storing Soybeans (SB). These operations are interdependent and all must be carried out correctly so that the quantity and quality of the soybeans are as high as is practicable when the crop is marketed and processed. The chapter presents some recommendations for harvesting, drying, handling, and storing soybeans, along with some history, recent developments, and trends for the future. The most important property of soybeans associated with their harvesting, drying, handling, and storing is moisture content. Soybean moisture content is defined assuming soybeans consist of two components: water and dry matter. Wet-basis moisture contents are used in the grain trade and in most other instances. Dry-basis moisture contents are sometimes used in research, especially related to the drying process. The chapter highlights that all moisture contents stated in the chapter are on wet basis.

MATHEMATICAL MODEL FOR SIMULATING HEADSPACE AND GRAIN TEMPERATURES IN GRAIN BINS

A computer simulation model for predicting temperatures of headspace air and the top meter of grain under both naturally and mechanically ventilated grain bin conditions is presented. Headspace air temperature was estimated using energy balances for the bin roof, exposed wall in the headspace, and headspace air exchange as a result of both natural and mechanical ventilation. Sub-models for estimating radiation (solar, sky, earth, and re-radiation) on bin roof and wall, and natural ventilation of the headspace due to wind and thermal buoyancy forces were involved in the headspace air temperature prediction model. Grain temperature was modeled by considering heat transfer due to conduction, natural convection caused by temperature differences between grain and ambient air, and convection due to forced air movement through grain during aeration or mechanical ventilation of the headspace. The accuracy and validity of the model are discussed. Simulations were conducted using 30 years of weather data for Minneapolis-St. Paul, Minnesota, and Lexington, Kentucky, for winter and summer conditions. Sensitivity analyses for the effect of bin surface conditions (new and weathered galvanized steel, and black- and white-colored steel bin surfaces) on the headspace air and grain temperatures were conducted. Headspace air changes per hour and headspace air temperatures were calculated for 10 and 20 m diameter bins with various sizes of eave gap and roof vents, and for two bin surface conditions (new galvanized steel and white-colored bin surfaces). Regression models to predict the number of air changes per hour in the headspace as a function of the ratio of headspace open area to headspace volume were developed. For galvanized steel bin surfaces, increasing openings in the headspace to increase natural ventilation reduced headspace air and grain temperatures. For white-colored bin surfaces, minimizing natural ventilation reduced headspace air and grain temperatures.

Effect of Broken Corn on Indianmeal Moth Survivability

Survivability of Indianmeal moth, Plodia interpunctella (Hubner), larvae fed a standard laboratory diet, whole corn with 0% broken kernels, whole corn with 5 to 7% broken kernels, and 100% broken corn kernels were assessed in our laboratory at 28oC, 65% RH, and 14 h light :10 h dark photoperiod cycle. A conventional low-oil yellow dent corn (about 3.9% oil content) and a highoil corn hybrid (about 7.7% oil content) were tested. Survivability was measured as the percentage emergence of pre-pupae, pupae, and adults at the end of the rearing period. For the standard laboratory diet, a mean ± SD of 97.5% ± 2.9 larvae survived. The mean ± SD percentages of larval survival for the conventional low-oil yellow dent corn were 6.7 ± 2.9, 63.8 ± 4.8, and 80.0 ± 14.7 for 0, 7, and 100% broken kernels, respectively. The mean ± SD percentages of larval survival for the highoil corn hybrid were 28.3 ± 12.6, 81.3 ± 4.8, and 100.0 ± 0.0 for 0, 5, and 100% broken kernels, respectively. Larval growth rate for high-oil corn was faster than for low-oil corn. Results indicate that cleaning corn before storage could reduce Indianmeal moth problems. Also, Indianmeal moth problems in high-oil corn varieties might be slightly greater than in corn varieties with normal oil levels.