A method developed for the screening of diethylene glycol (DEG) in toothpaste was released by the FDA in 2007. This method could not only quantify the DEG but also confirm if any potential interfering peak is pre- sen...A method developed for the screening of diethylene glycol (DEG) in toothpaste was released by the FDA in 2007. This method could not only quantify the DEG but also confirm if any potential interfering peak is pre- sent. However, disadvantages of this method such as intermittent shortages of the key reagent acetonitrile and the shorter than expected column-life issues have prompted a search for alternative solutions. An im- provement with an alternate “greener” extraction solvent is presented, and the method comparison and vali- dation are described in this article. The greener extraction solvent, ethanol with limited water, provided a better efficiency for the toothpaste sampling procedures. The limit of detection (LOD) and limit of quantita- tion (LOQ) are 0.0025% and 0.0084% in (w/w) unit, respectively. The sample recovery is 101.2%.展开更多
Several fields,such as biological,medical,public health,agricultural sciences,etc.,require circular balanced repeated measurement designs with fewer unequal number of repeated measure-ments than the number of treatmen...Several fields,such as biological,medical,public health,agricultural sciences,etc.,require circular balanced repeated measurement designs with fewer unequal number of repeated measure-ments than the number of treatments.Also,the availability and high cost of experimental subjects in these fields prefer the design in fewer experimental units.However,balancing the carryover effects of the treatments in minimal experimental subjects is one of the problems in this case.In this paper,several new series of minimal circular nearly strongly balanced RMDs in periods of two and three different sizes are constructed.The proposed construction of designs has high efficiency and,therefore,can save the cost of experimentations due to a fewer exper-imental subjects.Most of the designs are very useful because of the unavailability of strongly balanced RMDs for these combinations of parameters.A list of sets of shifts for the construction of minimal circular nearly SBRMDs has also been mentioned in the Appendix.展开更多
Nanofiltration(NF)using loose membranes has a high application potential for advanced treatment of drinking water by selectively removing contaminants from the water,while membrane fouling remains one of the biggest p...Nanofiltration(NF)using loose membranes has a high application potential for advanced treatment of drinking water by selectively removing contaminants from the water,while membrane fouling remains one of the biggest problems of the process.This paper reported a seven-month pilot study of using a loose NF membrane to treat a sand filtration effluent which had a relatively high turbidity(∼0.4 NTU)and high concentrations of organic matter(up to 5 mg/L as TOC),hardness and sulfate.Results showed that the membrane demonstrated a high rejection of TOC(by<90%)and a moderately high rejection of two pesticides(54%–82%)while a moderate rejection of both calcium and magnesium(∼45%)and a low rejection of total dissolved solids(∼27%).The membrane elements suffered from severe membrane fouling,with the membrane permeance decreased by 70%after 85 days operation.The membrane fouling was dominated by organic fouling,while biological fouling was moderate.Inorganic fouling was mainly caused by deposition of aluminum-bearing substances.Though inorganic foulants were minor contents on membrane,their contribution to overall membrane fouling was substantial.Membrane fouling was not uniform on membrane.While contents of organic and inorganic foulants were the highest at the inlet and outlet region,respectively,the severity of membrane fouling increased from the inlet to the outlet region of membrane element with a difference higher than 30%.While alkaline cleaning was not effective in removing the membrane foulants,the use of ethylenediamine tetraacetate(EDTA)at alkaline conditions could effectively restore the membrane permeance.展开更多
Quadrisyllabic words and phrases with normal stress of Mandarinwere used to study the tonal coarticuation.It was firstly found that the F<sub>0</sub>perturbation at the starting—point and the ending—poin...Quadrisyllabic words and phrases with normal stress of Mandarinwere used to study the tonal coarticuation.It was firstly found that the F<sub>0</sub>perturbation at the starting—point and the ending—point of the F<sub>0</sub> curve ineach syllable caused by tonal coarticulation is larger than the intrinsic F<sub>0</sub> dif-ference of vowels at the starting—point and the ending—point of it.As for thetonal coarticulation,it was discovered that tonal coarticulation in word andphrase with normal stress is different to that in the nonsense sequence with evenstress,and in word and phrase with normal stress,the tonal coarticulatory ef-fects are unidirectional,and the carryover effect does not extend to theending—point of tone—section of the following syllable and the anticipatory ef-fect does not extend to the starting-point of tone-section of the preceding one,and the F<sub>0</sub> perturbation by tonal coarticulation has its pattern.展开更多
文摘A method developed for the screening of diethylene glycol (DEG) in toothpaste was released by the FDA in 2007. This method could not only quantify the DEG but also confirm if any potential interfering peak is pre- sent. However, disadvantages of this method such as intermittent shortages of the key reagent acetonitrile and the shorter than expected column-life issues have prompted a search for alternative solutions. An im- provement with an alternate “greener” extraction solvent is presented, and the method comparison and vali- dation are described in this article. The greener extraction solvent, ethanol with limited water, provided a better efficiency for the toothpaste sampling procedures. The limit of detection (LOD) and limit of quantita- tion (LOQ) are 0.0025% and 0.0084% in (w/w) unit, respectively. The sample recovery is 101.2%.
文摘Several fields,such as biological,medical,public health,agricultural sciences,etc.,require circular balanced repeated measurement designs with fewer unequal number of repeated measure-ments than the number of treatments.Also,the availability and high cost of experimental subjects in these fields prefer the design in fewer experimental units.However,balancing the carryover effects of the treatments in minimal experimental subjects is one of the problems in this case.In this paper,several new series of minimal circular nearly strongly balanced RMDs in periods of two and three different sizes are constructed.The proposed construction of designs has high efficiency and,therefore,can save the cost of experimentations due to a fewer exper-imental subjects.Most of the designs are very useful because of the unavailability of strongly balanced RMDs for these combinations of parameters.A list of sets of shifts for the construction of minimal circular nearly SBRMDs has also been mentioned in the Appendix.
文摘Nanofiltration(NF)using loose membranes has a high application potential for advanced treatment of drinking water by selectively removing contaminants from the water,while membrane fouling remains one of the biggest problems of the process.This paper reported a seven-month pilot study of using a loose NF membrane to treat a sand filtration effluent which had a relatively high turbidity(∼0.4 NTU)and high concentrations of organic matter(up to 5 mg/L as TOC),hardness and sulfate.Results showed that the membrane demonstrated a high rejection of TOC(by<90%)and a moderately high rejection of two pesticides(54%–82%)while a moderate rejection of both calcium and magnesium(∼45%)and a low rejection of total dissolved solids(∼27%).The membrane elements suffered from severe membrane fouling,with the membrane permeance decreased by 70%after 85 days operation.The membrane fouling was dominated by organic fouling,while biological fouling was moderate.Inorganic fouling was mainly caused by deposition of aluminum-bearing substances.Though inorganic foulants were minor contents on membrane,their contribution to overall membrane fouling was substantial.Membrane fouling was not uniform on membrane.While contents of organic and inorganic foulants were the highest at the inlet and outlet region,respectively,the severity of membrane fouling increased from the inlet to the outlet region of membrane element with a difference higher than 30%.While alkaline cleaning was not effective in removing the membrane foulants,the use of ethylenediamine tetraacetate(EDTA)at alkaline conditions could effectively restore the membrane permeance.
文摘Quadrisyllabic words and phrases with normal stress of Mandarinwere used to study the tonal coarticuation.It was firstly found that the F<sub>0</sub>perturbation at the starting—point and the ending—point of the F<sub>0</sub> curve ineach syllable caused by tonal coarticulation is larger than the intrinsic F<sub>0</sub> dif-ference of vowels at the starting—point and the ending—point of it.As for thetonal coarticulation,it was discovered that tonal coarticulation in word andphrase with normal stress is different to that in the nonsense sequence with evenstress,and in word and phrase with normal stress,the tonal coarticulatory ef-fects are unidirectional,and the carryover effect does not extend to theending—point of tone—section of the following syllable and the anticipatory ef-fect does not extend to the starting-point of tone-section of the preceding one,and the F<sub>0</sub> perturbation by tonal coarticulation has its pattern.
