The conventional “pump-and-treat' technology for subsurface remediation of groundwater contaminated with volatile organic compounds(VOCs) such as 1,1,1-trichloroethane(TCA), a common chlorinated organic solvent, ...The conventional “pump-and-treat' technology for subsurface remediation of groundwater contaminated with volatile organic compounds(VOCs) such as 1,1,1-trichloroethane(TCA), a common chlorinated organic solvent, has limitation of prohibitively long treatment time due to extremely low water solubility of the VOCs. Surfactant-based soil remediation has emerged as the effective technology that substantially reduces the treatment time. In order to make the whole process economical, the surfactant used in soil washing has to be recovered and reused. This study examined the recovery of anionic surfactant, sodium dodecyl sulfate(SDS), from soil remediation fluids containing TCA, using a bench-scale membrane pervaporation unit. The effects of high TCA concentration, surfactant dosage, and flow rate on permeation flux and selectivity(α value) of the process were evaluated. In general, higher surfactant concentration yielded lower TCA flux and constant water flux, resulting in declining α values; higher flow rate of TCA feed stream results in higher VOC flux and selectivity, an indication of the effect of concentration polarization; higher TCA feed concentration produces higher TCA permeation across the membrane, however, the selectivity was virtually unchanged unless the total TCA concentration exceeded 2000 ppm.展开更多
trichloroethane(TCA), a common chlorinated organic solvent and volatile organic compound(VOC), was removed from contaminated groundwater by using a bench-scale membrane pervaporation unit. The effects of TCA concentra...trichloroethane(TCA), a common chlorinated organic solvent and volatile organic compound(VOC), was removed from contaminated groundwater by using a bench-scale membrane pervaporation unit. The effects of TCA concentration, temperature, and flow rate on permeation flux and selectivity(α value) of the process were evaluated. In general, higher temperature leads to higher VOC flux but lower selectivity; higher flow rate of TCA feed stream results in higher VOC flux and selectivity, an indication of the effect of concentration polarization; higher TCA feed concentration produces higher TCA permeation, however, the selectivity was virtually unchanged.展开更多
Many edible legumes contain high amounts of proteins, fibers, minerals and vitamins. Their essential amino acid composition and concentration complements the amino acids in wheat and other cereals. In addition, breads...Many edible legumes contain high amounts of proteins, fibers, minerals and vitamins. Their essential amino acid composition and concentration complements the amino acids in wheat and other cereals. In addition, breads fortified with protein rich legumes make the breads more palatable. In this study, we evaluated breads made from wheat flour partially substituted with soybean, navy bean, and lupin flours at 10%, 20%, and 30% levels. The physicochemical properties of breads were measured and compared with the control (made from 100% wheat flour). Statistical analysis was used to assess the significance of the differences. The breads fortified with soybean, lupin and navy bean flours showed remarkable springiness, similar to the breads made from wheat flour. However, the higher amount of substitution increased the firmness of the breads, probably due to the incorporation of additional fibers and proteins into the formulations. Compared to wheat bread, the volumes of 90:10 wheat-soybean, wheat-lupin, and wheat-navy bean breads decreased about 7%, 2%, and 10%, respectively. Higher substitution levels would result in a higher reduction in volume for all legumes tested. The volume reduction as a result of legume substitution appears to be navy bean flour > soybean flour > lupin flour. The inclusion of legumes in the bread formulations imparts a slightly darker crust color and crumb color with the exception of breads with the soybean flour substitution. Lupin appears to be the best substitution candidate among the legumes tested for fortified bread making. Lupin can be presented as a high-value protein source in developing marketable foods for health conscious consumers.展开更多
A novel amperometric biosensor prototype was fabricated using screen printing technique. The disposable single-use strips were made from conductive carbon ink and modified with fructosyl amino acid oxidase. The electr...A novel amperometric biosensor prototype was fabricated using screen printing technique. The disposable single-use strips were made from conductive carbon ink and modified with fructosyl amino acid oxidase. The electrodes and conducting paths were made solely with carbon ink and characterized by conductivity and cyclic voltammetry. The biosensor showed high current output, large linearity, and effectiveness for fructosyl valine as well as human blood samples. Amperometric studies were carried out using both fructosyl valine and human blood samples. With 5 uL sample volume, the biosensor showed strong amperometric response with good linearity for a wide range (0 to 8 mM). Diabetic and healthy blood samples showed sufficient difference in their amperometric responses that correlate well with their different hemoglobin A1c levels. These results demonstrate the feasibility of using this type of inexpensive single-use biosensor strips as the basis for determining hemoglobin A1c levels for diabetic patients.展开更多
文摘The conventional “pump-and-treat' technology for subsurface remediation of groundwater contaminated with volatile organic compounds(VOCs) such as 1,1,1-trichloroethane(TCA), a common chlorinated organic solvent, has limitation of prohibitively long treatment time due to extremely low water solubility of the VOCs. Surfactant-based soil remediation has emerged as the effective technology that substantially reduces the treatment time. In order to make the whole process economical, the surfactant used in soil washing has to be recovered and reused. This study examined the recovery of anionic surfactant, sodium dodecyl sulfate(SDS), from soil remediation fluids containing TCA, using a bench-scale membrane pervaporation unit. The effects of high TCA concentration, surfactant dosage, and flow rate on permeation flux and selectivity(α value) of the process were evaluated. In general, higher surfactant concentration yielded lower TCA flux and constant water flux, resulting in declining α values; higher flow rate of TCA feed stream results in higher VOC flux and selectivity, an indication of the effect of concentration polarization; higher TCA feed concentration produces higher TCA permeation across the membrane, however, the selectivity was virtually unchanged unless the total TCA concentration exceeded 2000 ppm.
文摘trichloroethane(TCA), a common chlorinated organic solvent and volatile organic compound(VOC), was removed from contaminated groundwater by using a bench-scale membrane pervaporation unit. The effects of TCA concentration, temperature, and flow rate on permeation flux and selectivity(α value) of the process were evaluated. In general, higher temperature leads to higher VOC flux but lower selectivity; higher flow rate of TCA feed stream results in higher VOC flux and selectivity, an indication of the effect of concentration polarization; higher TCA feed concentration produces higher TCA permeation, however, the selectivity was virtually unchanged.
文摘Many edible legumes contain high amounts of proteins, fibers, minerals and vitamins. Their essential amino acid composition and concentration complements the amino acids in wheat and other cereals. In addition, breads fortified with protein rich legumes make the breads more palatable. In this study, we evaluated breads made from wheat flour partially substituted with soybean, navy bean, and lupin flours at 10%, 20%, and 30% levels. The physicochemical properties of breads were measured and compared with the control (made from 100% wheat flour). Statistical analysis was used to assess the significance of the differences. The breads fortified with soybean, lupin and navy bean flours showed remarkable springiness, similar to the breads made from wheat flour. However, the higher amount of substitution increased the firmness of the breads, probably due to the incorporation of additional fibers and proteins into the formulations. Compared to wheat bread, the volumes of 90:10 wheat-soybean, wheat-lupin, and wheat-navy bean breads decreased about 7%, 2%, and 10%, respectively. Higher substitution levels would result in a higher reduction in volume for all legumes tested. The volume reduction as a result of legume substitution appears to be navy bean flour > soybean flour > lupin flour. The inclusion of legumes in the bread formulations imparts a slightly darker crust color and crumb color with the exception of breads with the soybean flour substitution. Lupin appears to be the best substitution candidate among the legumes tested for fortified bread making. Lupin can be presented as a high-value protein source in developing marketable foods for health conscious consumers.
文摘A novel amperometric biosensor prototype was fabricated using screen printing technique. The disposable single-use strips were made from conductive carbon ink and modified with fructosyl amino acid oxidase. The electrodes and conducting paths were made solely with carbon ink and characterized by conductivity and cyclic voltammetry. The biosensor showed high current output, large linearity, and effectiveness for fructosyl valine as well as human blood samples. Amperometric studies were carried out using both fructosyl valine and human blood samples. With 5 uL sample volume, the biosensor showed strong amperometric response with good linearity for a wide range (0 to 8 mM). Diabetic and healthy blood samples showed sufficient difference in their amperometric responses that correlate well with their different hemoglobin A1c levels. These results demonstrate the feasibility of using this type of inexpensive single-use biosensor strips as the basis for determining hemoglobin A1c levels for diabetic patients.
