There are several ways to convert a closure or interior operation to a different operation that has particular desirable properties. In this paper, we axiomatize three ways to do so, drawing on disparate examples from the literature, including tight closure, basically full closure, and various versions of integral closure. In doing so, we explore several such desirable properties, including hereditary, residual, and cofunctorial, and see how they interact with other properties such as the finitistic property.

This paper presents a fault detection and diagnosis (FDD) algorithm for various faults in the primary air data sensors (PADS) of an aircraft in the presence of external disturbances such as atmospheric turbulence. Rapid wind variations due to turbulence induce excessive error in the externally fitted air data probe measurements, which may lead to loss of control and misinterpretations by the flight crew. In adverse environmental conditions, the FDD of air data prefers robust and adaptive air data estimates that use an analytical redundancy approach with fewer computations. The proposed method considers the kinematics of the aircraft instead of the dynamics used in the state-of-the-art algorithms. The advantage of using kinematics is that it can reduce modeling errors significantly, avoiding high false alarm rates in the FDD process. For the estimation of stable and accurate air data under external disturbance, the inertial navigation system and global positioning system (INS/GPS) output are considered instead of actual air data probe or sensor measurements. The proposed algorithm uses estimates of air data using an exponentially weighted adaptive extended Kalman filter (EW-AEKF) to detect and diagnose PADS faults, which can perform well even in the presence of uncertain noise due to atmospheric turbulence experienced during flight. The simulation was carried out to validate the algorithm with flight data obtained from the X-Plane flight simulator under moderate atmospheric turbulence. The simulation experiments were carried out using the MATLAB programming platform. The results show that the proposed method achieves satisfactory FDD performance with lower root mean square error (RMSE) and computation time than traditional EKF-based algorithms.

Numerous perennial horticultural crops are grown across the southeastern United States. Blueberry and blackberry (also known as caneberry) are commonly found in roadside stands, promote agritourism via pick-your-own markets, are important for fresh market commercial production in the region, and when processed, provide desirable value added products. Season-long weed control using residual herbicides is crucial for these perennial fruit crops to maximize berry quality and yield. Studies performed from 2012 to 2014 in Lanier and Clinch counties in Georgia evaluated the effects of repeated applications of indaziflam at 35, 75, or 145 g ai ha−1 applied biannually in March and September (five total applications) on growth of ‘Alapaha’ rabbiteye and ‘Palmetto’ highbush blueberry, and ‘Apache’ thornless blackberry. All indaziflam treatments were mixed with glufosinate, and a glufosinate-only treatment was included as a check. Minor leaf chlorosis (<10%) was noted within 30 d after application for all blueberries for all treatments, but this was always transient. Blueberry stem diameter was not different for any treatment, even when indaziflam was applied up to 725 g ai ha−1 over 3 yr as compared to glufosinate alone. There was no chlorosis or stem diameter differences for blackberry noted for any treatment. Indaziflam applied in blueberry and blackberry production provides season-long control of numerous troublesome weed species, without causing injury or negatively impacting crop growth.

Currently, there are seven herbicides labeled for U.S. tobacco production; however, additional modes of action are greatly needed in order to reduce the risk of herbicide resistance. Field experiments were conducted at five locations during the 2017 and 2018 growing seasons to evaluate flue-cured tobacco tolerance to S-metolachlor applied pretransplanting incorporated (PTI) and pretransplanting (PRETR) at 1.07 (1×) and 2.14 (2×) kg ai ha−1. Severe injury was observed 6 wk after transplanting at the Whiteville environment in 2017 when S-metolachlor was applied PTI. End-of-season plant heights from PTI treatments at Whiteville were likewise reduced by 9% to 29% compared with nontreated controls, although cured leaf yield and value were reduced only when S-metolachlor was applied PTI at the 2× rate. Severe growth reduction was also observed at the Kinston location in 2018 where S-metolachlor was applied at the 2× rate. End-of-season plant heights were reduced 11% (PTI, 2×) and 20% (PRETR, 2×) compared with nontreated control plants. Cured leaf yield was reduced in Kinston when S-metolachlor was applied PRETR at the 2× rate; however, treatments did not impact cured leaf quality or value. Visual injury and reductions in stalk height, yield, quality, and value were not observed at the other three locations. Ultimately, it appears that injury potential from S-metolachlor is promoted by coarse soil texture and high early-season precipitation close to transplanting, both of which were documented at the Whiteville and Kinston locations. To reduce plant injury and the negative impacts to leaf yield and value, application rates lower than 1.07 kg ha−1 may be required in these scenarios.

This article presents a potential analytic redundancy approach to detect faults in the air data sensor of an aircraft. In modern aircraft, fault detection of air data sensors is performed using a complex voting mechanism, which requires the availability of redundant air data sensor in all situations. However, to continuously monitor operation and performance of these sensors, the analytic redundancy-based air data estimation and fault detection is highly preferred than estimation with air data probe measurements. The proposed algorithm uses the kinematics of aircraft to estimate air data and detect air data sensor fault. In this paper, a simple mathematical model is developed, which does not consider the forces and moments acting on aircraft and uses measurements only from the Inertial Measurement Unit (IMU) and Navigation System Data (NSD). In order to implement this approach, the Iterated Optimal Extended Kalman Filter (IOEKF) is developed to estimate air data, which provides an accurate and stable estimation. With the estimated states, the physical air data sensor measurements are compared and the residual is calculated to track each sensor performance and to detect the occurrence of a fault. The key advantage of this approach is that it does not require complex dynamic equations and is free from system uncertainties. The proposed algorithm is simulated in MATLAB software using flight simulator flight data and validated using the real-time flight data of Cessna Citation II transport aircraft.

Bermudagrass is a major forage species throughout Georgia and the Southeast. An essential part of achieving high-yielding, top-quality forages is proper weed control. Indaziflam is a residual herbicide that controls many broadleaf and grass species by inhibiting cellulose biosynthesis. Research conducted in Tift and Colquitt counties in Georgia determined optimal PRE rates for indaziflam for bermudagrass forage production. Treatments applied at spring greenup of established ‘Alicia’ bermudagrass included indaziflam at 47, 77, 155, or 234 g ai ha−1 PRE, pendimethalin at 4,480 g ha−1 PRE, a split application of indaziflam at 47 g ha−1 PRE followed by the same rate applied POST after the first cutting, and a nontreated control (seven treatments in all). Forages were machine harvested three times each year for each location beginning at least 47 d after treatment (DAT), with final cuttings up to 168 DAT. For all treatments, fresh- and dry-weight yields at each harvest and totals for the season did not differ from the nontreated control. Indaziflam at 155 and 234 g ha−1 did cause minor stunting at 44 DAT, but this was transient and not observed at the second harvest. Indaziflam applied PRE has the potential to provide residual control of troublesome weeds in bermudagrass forage and hay production, with ephemeral stunting at the recommended application rates.

S-Metolachlor is commonly used by soybean and cotton growers, especially with POST treatments for overlapping residuals, to obtain season-long control of glyphosate- and acetolactate synthase (ALS)–resistant Palmer amaranth. In Crittenden County, AR, reports of Palmer amaranth escapes following S-metolachlor treatment were first noted at field sites near Crawfordsville and Marion in 2016. Field and greenhouse experiments were conducted to confirm S-metolachlor resistance and to test for cross-resistance to other very-long-chain fatty acid (VLCFA)–inhibiting herbicides in Palmer amaranth accessions from Crawfordsville and Marion. Palmer amaranth control in the field (soil <3% organic matter) 14 d after treatment (DAT) was ≥94% with a 1× rate of acetochlor (1,472 g ai ha–1; emulsifiable concentrate formulation) and dimethenamid-P (631 g ai ha–1). However, S-metolachlor at 1,064 g ai ha–1 provided only 76% control, which was not significantly different from the 1/2× and 1/4× rates of dimethenamid-P and acetochlor (66% to 85%). In the greenhouse, Palmer amaranth accessions from Marion and Crawfordsville were 9.8 and 8.3 times more resistant to S-metolachlor compared with two susceptible accessions based on LD50 values obtained from dose–response experiments. Two-thirds and 1.5 times S-metolachlor at 1,064 g ha–1 were the estimated rates required to obtain 90% mortality of the Crawfordsville and Marion accessions, respectively. Data collected from the field and greenhouse confirm that these accessions have evolved a low level of resistance to S-metolachlor. In an agar-based assay, the level of resistance in the Marion accession was significantly reduced in the presence of a glutathione S-transferase (GST) inhibitor, suggesting that GSTs are the probable resistance mechanism. With respect to other VLCFA-inhibiting herbicides, Marion and Crawfordsville accessions were not cross-resistant to acetochlor, dimethenamid-P, or pyroxasulfone. However, both accessions, based on LD50 values obtained from greenhouse dose–response experiments, exhibited reduced sensitivity (1.5- to 3.6-fold) to the tested VLCFA-inhibiting herbicides.

Three field experiments were conducted in 1987 through 1989 to evaluate hogpotato control and rotational crop response resulting from applications of five herbicides. At the end of the first year, triclopyr and imazapyr controlled hogpotato late-season as high as 87 and 94%, respectively. Following a sequential application in 1988, triclopyr and imazapyr controlled 94 and 100% of hogpotato, respectively, during the 1989 growing season. Hogpotato biomass, collected at the termination of the experiments, was reduced by all treatments at all locations except at Altus where dicamba was applied in 1987 followed by a spot application of glyphosate in 1988. Soils from these experiments were bioassayed for residual herbicide activity using three potential rotational crop species. Tebuthiuron and imazapyr caused the greatest biomass reductions with cotton and wheat being the most sensitive species to these herbicides.

Palmer amaranth is the most troublesome weed of soybean in the southern United States. Field experiments were conducted at two Arkansas locations to determine the effect of drill-seeded soybean density on Palmer amaranth emergence. Experimental factors were multiple soybean seeding rates planted on a 19-cm-wide row spacing and the presence or absence of a PRE residual herbicide (flumioxazin plus pyroxasulfone). Soybean groundcover was measured throughout the growing season and daily soil temperature was recorded in selected soybean densities. In the absence of a PRE residual herbicide, at least a 1.7-fold reduction in Palmer amaranth emergence occurred when soybean were present. Differences in Palmer amaranth emergence occurred among soybean densities for both locations, suggesting the value of crop canopy in preventing Palmer amaranth emergence in the absence of an effective residual herbicide. In plots treated with the PRE herbicide, no difference in Palmer amaranth emergence occurred among soybean densities, except for the absence of soybean. Achievement of 95% groundcover by soybean reduced daily soil temperature fluctuations, which in turn reduced Palmer amaranth emergence. For both locations, soybean grain yields were greatest at the highest seeding rate (617,500 seed ha−1). In the presence of flumioxazin plus pyroxasulfone applied PRE, greater grain yields occurred compared to the absence of a PRE herbicide at both Fayetteville and Marianna. Based on this research, an effective PRE-applied residual herbicide has more influence on Palmer amaranth emergence than soybean density, and Palmer amaranth germination and emergence are dependent upon daily soil temperature fluctuations, which is a function of soybean density.

Sedges are problematic weeds that reduce quality of turfgrass sod, and herbicides may be needed for control prior to harvesting. The objective of this research was to evaluate application timing of halosulfuron and sulfentrazone on sod quality, tensile strength, and postharvest rooting of four warm-season turfgrasses. Bermudagrass injury from herbicides was minimal (< 10%), but injury to centipedegrass, St. Augustinegrass, and zoysiagrass was detected before harvesting and generally increased with sulfentrazone rate from 0.21 to 0.84 kg ai ha−1. Sod tensile strength was not reduced from the nontreated for bermudagrass and centipedegrass treated with herbicides, but tensile strength was reduced 15 and 22% following herbicide applications 1 wk before harvesting (WBH) St. Augustinegrass and zoysiagrass, respectively. Sulfentrazone at 0.84 kg ha−1 reduced zoysiagrass tensile strength 20% from the nontreated, but other treatments did not reduce measurements. Turfgrass injury from halosulfuron was negligible on all species, and treatments did not affect sod tensile strength of the four species. Treatments did not affect root mass of any species at 4 wk after sod transplanting. Sod quality after transplanting was reduced from the nontreated on several dates for centipedegrass and St. Augustinegrass when treated with sulfentrazone 1 and 2 WBH, and zoysiagrass quality was reduced from treatments 4 WBH. Bermudagrass quality after transplanting was not reduced from the nontreated by any herbicides. Results suggest sod harvesting should be delayed 1, > 2, > 2, and ≥ 4 weeks after sulfentrazone applications at labeled rates for bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass, respectively. Sod harvesting should be delayed 1, 2, ≥ 4, and 2 wk after halosulfuron treatments at 0.07 kg ai ha−1 for bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass, respectively.

Field studies were conducted 2004 and 2005 to evaluate weed control following POST applications of glyphosate in combination with either S-metolachlor (premix formulation), pyrithiobac, or trifloxysulfuron in conjunction with glyphosate in second-generation glyphosate-resistant cotton (Roundup Ready Flex). These herbicides were applied in combination with glyphosate in a two-application program at the 2-leaf (LF) (followed by glyphosate alone at the 10-LF growth stage), 6-LF (following glyphosate alone at the 2-LF growth stage), or 10-LF (following glyphosate alone at the 2-LF growth stage) cotton growth stages. No differences in weed control between residual herbicide were observed for goosegrass, hemp sesbania, Johnsongrass, Palmer amaranth, redroot pigweed, sicklepod, or smellmelon. Optimum control of barnyardgrass and browntop millet was achieved with glyphosate plus S-metolachlor. No differences were observed among application timings for control of goosegrass, hemp sesbania, Johnsongrass, pitted morningglory, and smellmelon. Control of barnyardgrass, browntop millet, Palmer amaranth, redroot pigweed, and sicklepod was optimized with residual herbicide application at the 2- or 10-LF timing. No yield differences were observed between residual herbicides, and seed cotton yield averaged 2,800 kg/ha. Yield was maximized when residual herbicide was applied at the 2- or 10-LF growth stage (2,960 to 2,730 kg/ha). Analysis based on numerical yield at particular residual-herbicide application timings and calculated yield for each timing based on the percentage of a standard three-application glyphosate program indicated the most consistent residual-herbicide timing for optimizing yield in a reduced-input Roundup Ready Flex weed-control program occurred at the two-leaf growth stage. All reduced-input programs, however, resulted in cotton yield of at least 93% of that obtained with the standard program.

Horseweed (Conyza canadensis) is a common weed in no-till crop production systems. It is problematic because of the frequent occurrence of biotypes resistant to glyphosate and acetolactate synthase (ALS)-inhibiting herbicides and its ability to complete its life cycle as a winter or summer annual weed. Tactics to control horseweed while controlling other winter annual weeds routinely fail; herbicide application timing and spring emergence patterns of horseweed may be responsible. The objectives of this experiment were to (1) determine the influence of fall and spring herbicides with and without soil residual horseweed activity on spring-emerging glyphosate-resistant (GR) horseweed density and (2) evaluate the efficacy and persistence of saflufenacil on GR horseweed. Field studies were conducted in southern Indiana and Illinois from fall 2006 to summer 2007 and repeated in 2007 to 2008. Six preplant herbicide treatments were applied at four application timings: early fall, late fall, early spring, and late spring. Horseweed plants were counted every 2 wk following the first spring application until the first week of July. Horseweed almost exclusively emerged in the spring at both locations. Spring horseweed emergence was higher when 2,4-D + glyphosate was fall-applied and controlled other winter annual weeds. With fall-applied 2,4-D + glyphosate, over 90% of the peak horseweed density was observed before April 25. In contrast, only 25% of the peak horseweed density was observed in the untreated check by April 25. Starting from the initiation of horseweed emergence in late March, chlorimuron + tribenuron applied early fall or early spring, and spring-applied saflufenacil at 100 g ai/ha provided greater than 90% horseweed control for 12 wk. Early spring–applied saflufenacil at 50 g ai/ha provided 8 wk of greater than 90% residual control, and early spring–applied simazine provided 6 wk of greater than 90% control. When applied in late spring, saflufenacil was the only herbicide treatment that reduced horseweed densities by greater than 90% compared to 2,4-D + glyphosate. We concluded from this research that fall applications of nonresidual herbicides can increase the rate and density of spring emerging horseweed. In addition, spring-applied saflufenacil provides no-till producers with a new preplant herbicide for foliar and residual control of glyphosate- and ALS-resistant horseweed.

Indaziflam is an effective PRE herbicide for annual bluegrass control, but soil residual effects could inhibit spring turf establishment in treated areas. To test this hypothesis, field experiments were conducted to evaluate establishment of bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass after fall indaziflam applications. Lateral spread of turfgrasses from plugs in summer generally had no meaningful differences from treatments. However, high indaziflam rates (70 and 140 g ai ha−1) had approximately two-fold more nonrooted stolons than the nontreated control while low rates (17.5 and 35 g ha−1), oxadiazon at 3360 g ai ha−1, and prodiamine at 840 g ai ha−1 were similar to the nontreated. Indaziflam at 70 g ha−1 and prodiamine applications in fall reduced sprig establishment of the four turf species from the nontreated control, but oxadiazon and low rates of indaziflam were similar. Bermudagrass establishment from seed was significantly reduced (20 to 50%) by indaziflam at 35 to 140 g ha−1, prodiamine, and oxadiazon, on several dates, but the low rate of indaziflam was similar to the nontreated at 10 wk after seeding. Overall, fall indaziflam applications at 17.5 to 35 g ha−1 appear safe on vegetative establishment of four warm-season turfgrasses in spring but reseeding bermudagrass in areas treated with rates > 17.5 g ha−1 may cause unacceptable delays in growth.

Isoxaflutole, a preemergence herbicide for use in corn, causes bleaching of plant tissue and plant death at low rates. A concern regarding widespread use of isoxaflutole is the unintentional exposure of high-value, minor hectareage crops that may be sensitive. Unintentional exposure could occur because of carryover from a previous application, spray drift, or contamination of irrigation water. The objective of this study was to determine the potential for injury to nine minor hectareage Michigan crops. Crops evaluated were: adzuki bean, alfalfa, carrot, cucumber, dry bean (navy and black beans), onion, sugar beet, and tomato. Experiments were conducted in the greenhouse to evaluate injury from low rates of isoxaflutole applied to soil to simulate carryover as well as low concentrations of isoxaflutole in 2.54 cm of irrigation water applied over the course of 1 h to 15-cm-tall plants. Isoxaflutole rates and concentrations that cause 20% injury (I20) were calculated using Seefeldt's log-logistic dose–response model. Regardless of application type, onion was always the least sensitive plant to isoxaflutole (I20 = 37 g/ha applied to soil and 194 μg/L in irrigation water), whereas navy bean and black bean were the most sensitive (I20 = 9 g/ha applied to soil and 5 μg/ L in irrigation water). The remaining plants exhibited intermediate sensitivity. All of the rates that resulted in injury were substantially less than the rates used for weed control in corn. Carryover from isoxaflutole applications in corn production may require plant back restrictions for certain sensitive crops.