Gregory A. Holt

Biobased composition boards made from cotton gin and guayule wastes: select physical and mechanical properties

Using biomass materials such as cotton gin byproducts (CGB) and guayule wastes in value-added products can help the economics of these crops, and additionally, aid in alleviating waste management and environmental problems. A study was conducted to assess important physical and mechanical properties of composition boards made from select CGB and guayule waste. Boards were made from five different ratios of cotton gin and guayule wastes: 100 : 0, 75 : 25, 50 : 50, 25 : 75, and 0 : 100. Overall, the biobased CGB and guayule waste boards showed great potential. However, refinement is needed to further enhance the performance of these biomasses for composite board applications.

Cotton bale moisture meter comparison at different locations.

Seven commercially available portable cotton bale moisture content (mc) meter-probe combinations were purchased by each of the three Agricultural Research Service Cotton Ginning Research Units and examined for precision and accuracy when used with commercially ginned cotton. The devices were used to measure the mc at the same six locations on a total of 96 cotton bales. Lint samples were obtained from the same locations in the bales for mc determination by the oven method resulting in more than 7000 meter readings with corresponding reference mc values. Based on oven-mc, the lint samples had mc in the range 2.3% to 9.4% wet basis. The oven-mc wet basis for the different samples in the same bale had a standard error from 0.15% to 0.42% wet basis. The different meters produced significantly different readings from each other, and these were significantly different from the oven-based mc. Most of the meters were found to have a significant offset from the oven-based mc ranging from -3.3 to 3.3 percentage points. However, the standard deviation of the difference between the individual readings of the meters and the oven-based mc resulted in estimates of precision of plus or minus one percentage point for most of the individual meters.

Influence of Harvesting and Gin Cleaning Practices on Southern High Plains Cotton Quality

Southern High Plains cotton has improved over the last ten years with regard to yield and fiber length and strength. In light of increased adoption of picker harvesting to preserve fiber quality and improve harvest productivity, ginning practices are needed which preserve fiber quality and maximize return to the producer. The objective of this work was to investigate the influence of harvest method, number of seed-cotton extractor cleaners (e.g. stick machines), and seed-cotton cleaning rate on foreign matter content, lint value, and fiber and yarn quality of cotton produced in the Southern High Plains. Compared to using only one stick machine, the use of two stick machines in the seed-cotton cleaning system removed more foreign material from both picker- and stripper-harvested cotton, but more foreign material was removed by the stick machines from stripper-harvested cotton because it had higher initial foreign matter content. Seed-cotton cleaning rate had no influence on stick machine cleaning performance for picked cotton but higher cleaning rates reduced stick machine cleaning performance for stripper-harvested cotton. Picker-harvested cotton exhibited improved HVI and AFIS fiber quality and higher bale values compared to stripper-harvested cotton. The use of two stick machines improved fiber color properties and reduced lint foreign matter content. Seed-cotton cleaning rate had a minimal effect on fiber quality and bale value was not influenced by the number of stick machines or seed-cotton cleaning rate. Total lint value, on a production area basis, was higher for stripper-harvested cotton after both lint cleaners compared to picker-harvested cotton due to yield differences. Yarn imperfections were reduced for ring spun yarn produced from picker-harvested cotton processed through one stick machine at the high cleaning rate. The findings of this work support a recommendation for using one stick machine in seed-cotton cleaning systems processing picker-harvested cotton and two stick machines in systems processing stripper-harvested cotton.

Assessment of particulate matter and ammonia emission concentrations and respective plume profiles from a commercial poultry house

Poultry-emitted air pollutants, including particulate matter (PM) and ammonia, have raised concerns due to potential negative effects on human health and the environment. However, developing and optimizing remediation technologies requires a better understanding of air pollutant concentrations, the emission plumes, and the relationships between the pollutants. Therefore, we conducted ten field experiments to characterize PM (total suspended particulate [TSP], particulate matter less than 10 μm in aerodynamic diameter [PM10], and particulate matter less than 2.5 μm in aerodynamic diameter [PM2.5]) and ammonia emission-concentration profiles from a typical commercial poultry house. The emission factors of the poultry house, which were calculated using the concentrations and fan speed, were 0.66 (0.29-0.99) g NH3-N bird-1d-1 for ammonia, 52 (44-168) g d-1AU-1 (AU = animal unit = 500 kg) for TSP, 3.48 (1.16-9.03) g d-1AU-1 for PM10, and 0.07 (0.00-0.36) g d-1AU-1 for PM2.5. PM and ammonia emission concentrations decreased as distance from the fan increased. Although emission concentrations were similar in the daytime and nighttime, diurnal and nocturnal plume shapes were different due to the increased stability of the atmosphere at night. Particle size distribution analysis revealed that, at a given height, the percentage of PM10 and PM2.5 was consistent throughout the plume, indicating that the larger particles were not settling out of the airstream faster than the smaller particles. Overall, the direction of the measured air pollutant emission plumes was dominated by the tunnel fan ventilation airflow rate and direction instead of the ambient wind speed and direction. This is important because currently-available air dispersion models use ambient or modeled wind speed and direction as input parameters. Thus, results will be useful in evaluating dispersion models for ground-level, horizontally-released, point sources and in developing effective pollutant remediation strategies for emissions.

Lidar Method to Estimate Emission Rates from Extended Sources

AbstractPollutant emissions to the atmosphere commonly derive from nonpoint sources that are extended in space. Such sources may contain area, volume, line, or a combination of emission types. Currently, point measurements, often combined with models, are the primary means by which atmospheric emission rates are estimated from extended sources. Point measurement arrays often lack in spatial and temporal resolution and accuracy. In recent years, lidar has supplemented point measurements in agricultural research by sampling spatial ensembles nearly instantaneously. Here, a methodology using backscatter data from an elastic scanning lidar is presented to estimate emission rates from extended sources. To demonstrate the approach, a known amount of particulate matter was released upwind of a vegetative environmental buffer, a barrier designed to intercept emissions from animal production facilities. The emission rate was estimated downwind of the buffer, and the buffer capture efficiency (percentage of particl...

Collection Efficiency Evaluation of Baffle-Type Pre-Separator Configurations: Effects of Baffle Location and Inlet Velocities

Some cotton gins across the Cotton Belt use an abatement system consisting of a baffle-type pre-separator followed by cyclones to control the emissions from the cotton gins various exhausts. Very limited information exists in the literature which discusses the effects of baffle location and critical velocity on the pre-separators collection efficiency. In this study, a range of critical air velocities and loading rates were evaluated to determine the effect of baffle location of the pre-separators collection efficiency when using cotton gin waste. None of the treatments significantly affected the over-sized cyclone or over-all collection efficiency. The pre-separator collection efficiency was higher (81%) when the baffle placed at one-third the overall width of the pre-separator from the inlet than when placed at one-half (78%) or two-thirds (75%). The pre-separator collection efficiency was 79.4% at 18.3-m s-1 (3600-fpm) inlet velocity which was significantly higher than 78.2% at 20.3 m s-1 (4000 fpm) and 78.5% at 22.4 m s-1 (4400 fpm). Loading rate did significantly affect the pre-separator efficiency, but not to the extent of inlet velocity. The sieve analysis indicated that the pre-separator removed the majority of material larger than 180 µm; however, the pre-separator did allow a substantial amount of lint to pass through to the cyclone. The baffle-type pre-separator performed well in reducing the course material loading rate entering the cyclone.

Manual Fractionation of MDTA-3 Trash Samples from Cotton Lint

One goal of lint cleaning at a cotton gin is to reduce the non-lint material to an acceptable level with minimal fiber damage. In an effort to improve lint cleaner performance, an initial study was conducted on lint collected before and after lint cleaning from 9 commercial gins across the cotton belt to characterize non-lint content. Samples from this study were first processed with a MDTA-3 (Micro Dust and Trash Analyzer 3, SDL Atlas, Stockport, England) to separate lint, trash, fiber fragments, and dust to determine the fractional composition of the original sample. The trash portion was retained for additional manual fractionation to determine the percent of material classified as seed coat fragments (SCF), motes, funiculi, sticks, leaf, bark, lint, and “other” material. Leaf, SCF, and sticks were the largest fractions accounting for 81% of the total trash sample. Overall, total trash decreased by 57% due to lint cleaning, and trash fractions remained consistent in samples before and after lint cleaning. Lint cleaning efficiency in terms of SCF was less than the overall cleaning efficiency, and lint cleaning efficiency for bark, mote, and other (all minor components) was higher than the overall cleaning efficiency. The lint cleaning efficiency for SCF was increased significantly when higher SCF levels were found before the lint cleaner, but this trend was not found for other fractions. Results of this experiment will help direct future studies to improve lint cleaning.