Werner Zimmt

Efficient extraction method to collect sugar from sweet sorghum

BackgroundSweet sorghum is a domesticated grass containing a sugar-rich juice that can be readily utilized for ethanol production. Most of the sugar is stored inside the cells of the stalk tissue and can be difficult to release, a necessary step before conventional fermentation. While this crop holds much promise as an arid land sugar source for biofuel production, a number of challenges must be overcome. One lies in the inherent labile nature of the sugars in the stalks leading to a short usable storage time. Also, collection of sugars from the sweet sorghum stalks is usually accomplished by mechanical squeezing, but generally does not collect all of the available sugars.ResultsIn this paper, we present two methods that address these challenges for utilization of sweet sorghum for biofuel production. The first method demonstrates a means to store sweet sorghum stalks in the field under semi-arid conditions. The second provides an efficient water extraction method that can collect as much of the available sugar as feasible. Operating parameters investigated include temperature, stalk size, and solid–liquid ratio that impact both the rate of sugar release and the maximal amount recovered with a goal of low water use. The most desirable conditions include 30°C, 0.6 ratio of solid to liquid (w/w), which collects 90 % of the available sugar. Variations in extraction methods did not alter the efficiency of the eventual ethanol fermentation.ConclusionsThe water extraction method has the potential to be used for sugar extraction from both fresh sweet sorghum stalks and dried ones. When combined with current sugar extraction methods, the overall ethanol production efficiency would increase compared to current field practices.

EFFECTIVE NITRATE CONTROL WITH ELECTROKINETICS IN SANDY SOIL

Nitrate contamination of surface and ground water is a problem worldwide. Nitrate in drinking water presents a human health risk. The major source of nitrate contamination is believed to be nitrogen fertilizer from agricultural fields. Best Management Practices have been developed to guide fertilizer use and minimize nitrogen losses, but they do not address control of nitrate movement from the crop root zone. It is proposed that electrokinetics, an in-situ method, could be used to control nitrate movement, retaining it near the root zone. This article reports results from a study on nitrate movement and pH changes in a vertical, partially saturated sandy soil column subjected to an electrical current. The highest measured nitrate concentration (7155 mg/L) was within 5 mm of the anode after application of a 6 h 80 mA current. The nitrate concentration at the cathode was 1/5 of the inflow solute concentration. The pH was 11 near the cathode, 3.5 near the anode, and showed little change in intermediate layers. Studies of different nitrate concentrations and electrical current levels suggest that 80 mA electrical current applied for 6 h duration might effectively control nitrate migration in similar sandy soil conditions.

Nitrate pollution control in different soils by electrokinetic technology

Previous studies found that a small DC electrical current could attract anions to the anode in sandy soil, even with solute flow towards the cathode. Laboratory experiments were conducted in a vertical, partially saturated column with different soils to determine if nitrate transport could similarly be controlled using electrokinetic (EK) technology. Nitrate concentration, pH value, electrical potential difference, and soil water content were measured for three soils at selected times at different distances from the anode. Constant electrical current was applied to the system for 9 h, and measurements continued for a total of 48 h. The results demonstrated that nitrate can be strongly retained near the anode against gravity in sandy soil with an 80 mA (0.5 mA/cm2) current input. When the percentage of clay in the soil was increased, the EK effect on ion movement decreased; the transport of both ions and water were inhibited by fine clay particles. The loamy soil showed a slight increase in nitrate concentration near the anode, but the clayey soil showed no change. An increase in pH near the cathode was seen in all soils. Water content for sandy soil was higher at the bottom of the column and lower at the top of the column, but for loam and clay soils, the lowest water content was found above the cathode near the bottom of the column. Electrical potential difference between the two electrodes showed that the sandy soil required the highest electrical potential difference to obtain the desired current level; loamy and clayey soils required less. For sandy soil, the highest potential difference was found near the top of the column, but for loam and clay soils, the highest electrical potential difference was measured near the bottom, next to the cathode, suggesting that these locations were the critical zones limiting electrical ion transport.

THE USE OF POLYTETRAFLUOROETHYLENE (PTFE) FILM FOR STORAGE SUPPORTS

AbstractWide-format rolls of polytetrafluoroethylene (PTFE) film, best known as plumbers or Teflon tape, are being developed for use as a final covering on storage supports for objects with particularly fragile or vulnerable surfaces. The films smooth and pliable characteristics are well suited to protecting fragile surfaces from abrasion and similar mechanical damage. Included in the paper are descriptions of how the film was used for rehousing projects at the Arizona State Museum.

Testing for Gums, Starches, and Mucilages in Artifacts with O-toluidine

The o-toluidine test for complex carbohydrates was first developed for the identification of gums, mucilages, and starches using small samples from artifacts. This test as described for the analysis of museum collections was revised by systematically testing reference materials. This paper reports on the color reactions obtained on treating reference materials with the o-toluidine reagent to better understand the resultant color reactions of various gums, mucilages, and starches. The green color reaction commonly reported in the literature was found to be only partially accurate. This test will yield a green color for polysaccharides that yield only aldohexoses upon hydrolysis, such as starches and certain mucilages. Gum exudates and mucilages that are polysaccharides of both aldohexoses and aldopentoses yield a brown color reaction. Also discussed are the classification, sources, and uses of various plant polysaccharides and where this microchemical test was useful in understanding the collections at the Arizona State Museum.

Nitrate Pollution Control in Different Soils by Electrokinetic

Laboratory experiments were conducted to determine if nitrate transport in soils can be controlled using electrokinetic (EK) technology. Nitrate concentration, pH, electrical potential and soil water content were measured in soil column tests with three soils at different distances from the anode and at desired times. Constant electrical current was applied to the system for 9 hrs and continued for a total of 48 hrs. The results showed that in sandy soils nitrate can be strongly retained near the anode, even against gravity and drainage effects. When the percentage of clay in the soil was increased, the EK effect was decreased; due to the increase of fine clay particles both the transports of ions and the water were inhibited. The loam soil showed slight increase of nitrate concentration near the anode, but the clay soil showed no change. An increase of pH near the cathode was seen in all soils. Water content measurement showed that in sandy soil, water content was higher at the bottom and lower at the top, but for loam and clay soil, the lowest water content was at the layer just above the cathode. The electrical potential required to obtain constant amperage was 97.23 V in sandy soil, 18.24 V in loamy soil and 14.22 V in clayey soil. For sandy soil, the highest potential fraction was found near the top of the column in the system, but for loam and clay soil, the highest potential portion was near the bottom, next to the cathode, suggesting that these locations were the critical zones limiting the ion transport.