Modelling the leaching of imazapyr in a railway embankment

The use of herbicides on railway tracks is known to present a risk to groundwater, but little is known of the mechanisms influencing leaching through the coarse material used to construct railway embankments. Therefore, in the present study, four different models based on the convection-dispersion equation (CDE) were compared with previously reported field data on the leaching of imazapyr. In particular, the significance of non-equilibrium processes was investigated by comparing different CDE formulations accounting for preferential finger flow, particle-facilitated transport and kinetic sorption. The traditional CDE assuming 'local equilibrium' based on 24 h batch sorption data gave poor results (model efficiency - 1.1). It strongly underestimated leaching of imazapyr in the first 4 months following application, thus confirming the importance of non-equilibrium transport processes. Accounting for short-term sorption kinetics made little difference, giving similar results to the 'local equilibrium' CDE simulation. A simulation accounting for particle-facilitated transport could accurately match this accelerated transport, and also gave the best overall fit to the data (model efficiency 0.76). However, not even this model could match the long-term retention of imazapyr residues observed close to the soil surface more than 1 year after application, and it also underestimated the time of breakthrough to groundwater. This strongly suggests that a long-term retention/sorption process not included in any of the models tested (i.e. sorption hysteresis or bound residues) acted to retard leaching. The formation of 'protected' residues was also indicated by a much slower degradation of imazapyr more than 1 year after application. Industry.     

Comparison of Alkali and Conventional Corn Wet-Milling: 1-kg Procedures

An alkali corn wet-milling process was developed to evaluate the process as a method to produce high purity corn starch and coproducts with added value. Using a single hybrid (R1064 × LH59), the effects of alkali concentration (0.18–0.82% NaOH), time (29–61 min), and temperature (36–75°C) were investigated. Starch yield was not affected by steep time or temperature. Starch yield was optimal at 65.2% using 0.5% alkali. Increasing the concentration of alkali to 0.82% or decreasing it to 0.18% caused a decrease in starch yield of 8–10 percentage points. Other wet-milling products (fiber, germ, and gluten) also were affected. Steep conditions of 0.5% NaOH, 60 min, and 45°C gave optimal starch yield. Comparisons between alkali and sulfur dioxide wet-milling processes, using 1-kg sample size, were performed on 10 commercial yellow dent corn hybrids. The alkali process averaged 1.7 percentage points more starch than the sulfur dioxide process. Each hybrid had a higher starch yield when wet-milled with the alkali method. Alkali wet-milling produced pure corn starch with <0.30% protein (db).     

Effect of Corn Oil on Thin Stillage Evaporators

Removal of the germ at the front end of the dry-grind ethanol process using the Quick Germ process reduces the amount of oil in thin stillage. Thin stillage with 4–6% solids is dewatered to 25–30% solids by evaporation. Thin stillage evaporators in a dry-grind ethanol plant foul and have to be periodically taken down for maintenance and cleaning. Fouling caused by thin stillage containing different amounts of oil was studied using an annular fouling probe. It was determined that the rate of fouling in a drygrind ethanol plant is three times higher when compared with that in a wet-milling ethanol plant. The addition of oil to wet-milled thin stillage significantly affected the rate of fouling. Fouling resistance increased with an increase in oil concentration for wet-milled thin stillage up to a concentration of 1.41%. At a concentration of 1.47%, the rate of fouling decreased. As the concentration of oil increased in dry-grind ethanol thin stillage, the rate of fouling decreased. These results suggest that the Quick Germ process will reduce the rate of heat transfer equipment fouling in a drygrind ethanol plant, which will decease capital costs and maintenance costs.     

Fate of Bt Protein and Influence of Corn Hybrid on Ethanol Production

Corn hybrids were compared to determine the fate of recombinant Bt protein (CRY1Ab from Bacillus thuringiensis) in coproducts from dry grind and wet‐milled corn during production of fuel ethanol. Two pairs of Bt and non‐Bt hybrids were wet milled, and each fraction was examined for the presence of the Bt protein. Bt protein was found in the germ, gluten, and fiber fractions of Bt hybrids. In addition, one set of Bt and non‐Bt hybrids were treated by the dry‐grind ethanol process and Bt protein was monitored during each step of the process. The Bt protein was not detected after liquefaction. Subsequent experiments determined that the Bt protein is rapidly denatured at liquefaction temperatures. Finally, five hybrids were compared for ethanol yield after dry grinding. Analysis of fermentation data with an F‐test revealed the percent of total starch available for conversion into ethanol varied significantly among the hybrids (P < 0.002), indicating ethanol yield is not exclusively dependent on starch content. No difference, however, was observed between Bt and non‐Bt corn hybrids for either ethanol productivity or yield.     

Comparison of Yield and Composition of Oil Extracted from Corn Fiber and Corn Bran

We recently reported that corn fiber oil contains high levels of three potential cholesterol-lowering phytosterol components: ferulate-phytosterol esters (FPE) (3–6 wt%), free phytosterols (1–2 wt%), and phytosterol-fatty acyl esters (7–9 wt%). A previous study also indicated that corn bran oil contained less phytosterol components than corn fiber oil. The current study was undertaken to attempt to confirm this preliminary observation using more defined conditions. Accordingly, oil was extracted from corn fiber and corn bran prepared under controlled laboratory conditions, using the same sample of corn hybrid kernels for each, and using recognized bench-scale wet-milling, and dry-milling procedures, respectively. After extraction, the chemical composition of the phytosterol components in the oil were measured. This study confirmed our previous observation—that FPE levels were higher in corn fiber oil than in corn bran oil. During industrial wet-milling, almost all of the FPE are recovered in the fiber fraction (which contains both fine and coarse fiber). During laboratory-scale wet-milling, ≈60–70% of the FPE are recovered in the coarse fiber (pericarp) and 30–40% are recovered in the fine fiber. During laboratory-scale dry-milling, <20% of the FPE are recovered in the bran (pericarp), and the rest in the grits. The recoveries of the other two phytosterol components (free phytosterols and phytosterol-fatty acyl esters) revealed a more complex distribution, with significant levels found in several of the dry- and wet-milled products.     

Einfluss von Blattdüngung und Lagerverfahren auf die Druckstellenempfindlichkeit von Äpfeln

The influence of foliar fertilization and storage method on the bruise sensitivity of apples was investigated. The foliar fertilization was carried out with calcium, manganese or zinc by the cultivars ‘Braeburn’ and ‘Jonagold’. Fruits have been stored at 2°C in normal atmosphere (cold storage) or in film bags (CA-/ULO-storage (CA?=?controlled atmosphere, ULO?=?ultra low oxygen) for three months. Monthly fruits were bruised with a penetrometer applying a range of pressures. One day later the appearance of bruises was evaluated. Increasing pressures resulted in bruises of increasing severity. Foliar fertilization had no effect on the bruise susceptibility of both cultivars. The application of manganese and zinc led to an increase of manganese and zinc concentration in the leaves. The calcium concentration of fruits was not affected by the manganese and zinc application. The application of calcium increased the calcium concentration in the leaves and fruits to a lower degree, but no effect on the bruise sensitivity could be observed. No differences were observed in storage conditions, but duration of storage increased the bruise sensitivity of ‘Braeburn’. In comparison of the cultivars ‘Braeburn’ was less sensitive than ‘Jonagold’.     

Effect of Sodium Hydroxide,Calcium Hydroxide,and Potassium Hydroxide on Debranning of Corn

The effect of sodium hydroxide, calcium hydroxide, and potassium hydroxide, and processing conditions (alkali concentration and soaking time) on corn debranning was studied at a temperature of 55°C. Fiber yield, soluble dry matter loss, and total dry matter removed were determined for different alkalies and processing conditions. Sodium hydroxide and potassium hydroxide resulted in maximum fiber yields of 3.38 and 3.48%; maximum soluble dry matter loss of 7.63 and 10.96%; and maximum total dry matter removed of 10.52 and 13.26%. Calcium hydroxide at 6% concentration level resulted in negligible fiber yield, soluble dry matter loss, and total dry matter removed with soak times up to 16 hr. Sodium hydroxide has higher debranning action than potassium hydroxide at 3 and 6% concentration levels; whereas, at 9% concentration level, potassium hydroxide has higher debranning action.     

Effect of Kernel Size,Location, and Type of Damage on Popping Characteristics of Popcorn

Popping characteristics, specifically expansion volume and popping time, were studied for damaged popcorn. A single variety of commercial undamaged yellow popcorn was separated into four size fractions (D < 4.36, 4.36 < D < 5.16, 5.16 < D < 5.95, and D > 5.95 mm) by screening with round-hole sieves. Kernels were damaged using a razor knife by either slicing a 2-mm diameter piece of the endosperm or the germ or by cutting through the pericarp and seed coat into the endosperm or the germ ≈2 mm. A total of five combinations of location and damage were studied (tip cap removed, side cut, side sliced, germ cut, and germ sliced) for each kernel size. A control sample with no damage was also analyzed for each size fraction. All of the damaged kernels (regardless of type of damage) popped, but they had expansion volumes 9.1–47.5% smaller than those of undamaged kernels. The expansion volume of damaged kernels increased by 52.5–85.7%, depending on the damage, when the size of the kernel increased from <4.36 mm to >5.95 mm. Removing the tip cap and slicing through the germ caused less loss of expansion volume than did other types of damage. Damaged popcorn kernels had faster popping times (12.2–24.0 sec) than did undamaged kernels (30.9–34.6 sec). Popping times increased with increasing kernel size for all types of damage.     

Quick Fiber Process: Effect of Mash Temperature,Dry Solids,and Residual Germ on Fiber Yield and Purity

Preliminary calculations showed that recovery of fiber before fermentation in the dry grind ethanol facilities known as the Quick Fiber process increases fermenter capacity and reduces ethanol production cost by as much as 4 ¢/gal. The objective of the current research was to evaluate the effect of mash temperature, dry solids, and residual germ on fiber yield and purity when using the quick fiber process. Fiber was recovered by flotation and skimming, while maintaining a specified temperature, dry solids, and residual germ in the mash. Varying temperature and dry solids in the mash resulted in a statistically significant effect on the fiber yield, neutral detergent fiber (NDF) content, and weight of NDF/100 g of dry corn. Varying residual germ in the mash resulted in statistically significant differences for NDF through dilution and the weight of NDF/100 g of dry corn. The highest fiber yield was 10.9% at 45°C, 23% dry solids, and 15% residual germ; the highest NDF was 50.9% at 30°C, 21% dry solids, and 0% residual germ. The highest weight of NDF/100 g of dry corn was observed at 45°C, 23% dry solids, and 0% residual germ.