Operational Field Trial Research Articles

Decisions, Decisions … and Even More Decisions: Evaluation of a Digitized Mission Support System in the Land Warfare Domain

Digitized mission support systems are currently being introduced in the military arena. The projected benefits include quicker, better informed, more efficient decision making by the teams using them; however, these claims are often made without appropriate scientific testing. A live operational field trial of a land warfare digital mission support system was observed, and an integrated framework of Human Factors methods was used to evaluate performance with the mission support system. The findings indicated that, as a corollary of various flaws associated with the digital system, decision making was found to be more difficult, more drawn out, and more susceptible to error. Rather than augment the decision-making process, in some cases these flaws were seen to create further decision-making requirements for users. In closing, the implications of this study and the wider naturalistic decision making literature for the design of digitized mission support systems are discussed.

Comparison of four glyphosate herbicide formulations for white spruce release treatment

An operational field trial was established to compare the efficacy and white spruce (Picea glauca (Moench) Voss.) tolerance of three alternative glyphosate formulations to Vision®, Canada's originally registered forestry formulation. The trial was done at operational scale (minimum treatment unit 7 ha) using helicopter application of all products. The tested alternatives included two new generic formulations, recently registered for forestry in Canada (Glyfos-Forza® and Vantage®), and one widely used formulation in the United States (Accord®). All four formulations provided greater than 90% control of bluejoint reedgrass (Calamagrostis canadensis (Michx.) Beauv.) through 23 months post-treatment (p > 0.27). Assessed over the same period, the three Canadian formulations provided equivalent white spruce tolerance (p > 0.10), with seedlings exhibiting only minor, non-lethal herbicide injury. Accord®, not registered for use in Canada, consistently provided the best crop tolerance, but differences were only statistically significant 11 months post-treatment (p = 0.10). The results suggest that foresters may choose among the glyphosate formulations available in Canada without concern for product-related differences in efficacy and white spruce tolerance. Key words: glyphosate, white spruce, conifer tolerance, Calamagrostis canadensis, efficacy

Comparison of an Organophosphate Insecticide with a Mycoinsecticide for the Control of Oedaleus senegalensis (Orthoptera: Acrididae) and Other Sahelian Grasshoppers at an Operational Scale

Operational scale field trials were conducted in 1996 and 1997, in the east of the Niger Republic, on 50 and 800 hectare plots, to compare the efficacy of an oil based formulation of the entomopathogenic fungus, Metarhizium anisopliae (flavoviride) var. acridum (Deuteromycotina: Hyphomycetes) with fenitrothion for the control of Sahelian grasshoppers. The Senegalese Grasshopper Oedaleus senegalensis Krauss was the most abundant species in the trials. M. anisopliae was applied at 5 x 1012 spores ha-1 at volume application rates of 2 and 0.5 l ha-1 in successive years. Fenitrothion was applied at 220 g/ha-1 at 1.25 and 0.22 l ha-1 volume application rates. Ultra low volume equipment mounted on a vehicle (1996) or a fixed wing aircraft (1997) was used for application. The M. anisopliae treatment reduced the grasshopper population significantly after 7 days and by 93% within 16 days. Fenitrothion caused a population reduction of more than 90% shortly after application, but due to immigration, the grasshopper population recovered to the initial level within 16 days. Grasshoppers treated with the fungus and given the opportunity to thermoregulate in the sun died more slowly than grasshoppers incubated in the shade. The survival of spores in the spray residue of the M. anisopliae plots assessed by exposing grasshoppers to the sprayed vegetation at intervals and monitoring disease levels during subsequent laboratory incubation, showed the spray residue to remain highly infective, for three weeks after spraying. At the end of the 1997 season, egg pod density and viability in the plot treated with the fungus was reduced compared with both untreated and the fenitrothion plots. Compared with the existing practice of large-scale treatment of grasshopper infestations with fenitrothion, use of M. anisopliae would not only be safer to mammals and less damaging to non-target organisms, but also be more effective in the long-term control of grasshoppers.

Glyphosate efficacy on eastern Canadian forest weeds. Part I: experimental design and on-target deposit

Experimental methods and resulting on-target deposit data are presented for an operational field trial designed to evaluate glyphosate (Vision®) efficacy using two different dispersal systems (AU5000 Micronairs® and conventional hydraulic nozzles). A range of glyphosate rates (0, 0.25, 0.50, 0.75, and 1.00 kg acid equivalent per hectare) was aerially applied in a randomized complete block design to four cutover sites in New Brunswick. Formulation, tank-mix, droplet, and chemical analyses were conducted to quantify actual on-target deposit for each treatment. Data for the calibrated portion of each swath suggested that the Micronair system produced a slightly narrower drop-diameter spectrum (0–677 μm, volume median diameter = 300 μm) than the hydraulic system (0–1085 μm, volume median diameter = 425 μm). Analysis of variance and orthogonal contrasts indicated that on-target deposit for the Micronair system (average accountability = 71%) was not significantly different from that of the hydraulic system (average accountability = 82%) for three of four rates tested. Unrepresentative meteorological and site conditions affecting Micronair treatments in two blocks resulted in reduced deposit for the treatment of 1.00 kg acid equivalent per hectare. Substantial variability within treatments was observed for both dispersal systems (41 and 47% coefficient of variation for Micronair and hydraulic systems, respectively). Overall, results suggest no significant differences between the two dispersal systems (as calibrated) in terms of on-target deposit efficiency or variability. Both on-target droplet density and chemical deposit data reflected differences associated with blocks. This fact highlights the need for further studies on meteorological and operational factors on deposit.

The Bristol University Neutron Dosimetry System

The neutron dosimetry system developed at Bristol is approaching the stage of operational field trials. The system is based on recording recoil proton tracks in conventionally etched PADC plastic using a fully automated image analysis system developed in this laboratory. Two features contribute to the achievement of a low dose threshold: high quality plastic is manufactured in this laboratory and undergoes extensive quality control tests prior to acceptance for use in dosimetry, and a readout system with high efficiency for rejecting background events is used. The principal dosemeter that has been developed consists of three orthogonal elements, each containing two 3 cm x 1 cm plastics on either side of a polyethylene radiator. On each plastic an area of 0.15 cm2 is scanned giving a total active area of 0.90 cm2. Each plastic is coded in both arabic numerals for manual identification and a corresponding bar code for computer recognition. There is provision for the inclusion of a seventh pre-dosed plastic for calibration purposes. The track counts from the six plastics are added with different weightings to achieve a measure of dose which is independent of irradiation direction when worn on the body. The device has been calibrated using monoenergetic neutrons in the range 100 keV to 14.7 MeV at NPL, and using the recent CENDOS exposure. If the track counts are added without weighting, the device has a nominal response of 120 tracks cm-2.mSv-1 and an energy threshold at 200 keV. Taken together with a background of 20 track cm-2, a dose threshold of around 80 µSv is implied. A simpler dosemeter, using a single plastic/radiator combination, may also be considered. If a 1 cm2 device is used for normal incidence exposure the dose threshold is calculated to be 25 µSv. The lower figure is produced because the simpler device contains no plastics edge-on to the beam.

24-Type loop checking system - Application and field test results in the bell telephone system

A simple inexpensive system for checking transmission on subscriber lines has been developed. The system includes a small portable loop checker for use at the customer location and a sweep-frequency generator located at the central office. Operational field trials to determine the most effective methods of applying the system and the results obtained are discussed.