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81.
Schmidt Sherry L. Myers Michele D. Kelley Stephen S. McMillan James D. Padukone Nandan 《Applied biochemistry and biotechnology》1997,(1):469-482
The use of membrane processes for the recovery of fermentation products has been gaining increased acceptance in recent years.
Pervaporation has been studied in the past as a process for simultaneous fermentation and recovery of volatile products such
as ethanol and butanol. However, membrane fouling and low permeate fluxes have imposed limitations on the effectiveness of
the process. In this study, we characterize the performance of a substituted polyacetylene membrane, poly[(l-trimethylsilyl)-l-propyne]
(PTMSP), in the recovery of ethanol from aqueous mixtures and fermentation broths. Pervaporation using PTMSP membranes shows
a distinct advantage over conventional poly(dimethyl siloxane) (PDMS) membranes in ethanol removal. The flux with PTMSP is
about threefold higher and the concentration factor is about twofold higher than the corresponding performance achieved with
PDMS under similar conditions. The performance of PTMSP with fermentation broths shows a reduction in both flux and concentration
factor relative to ethanol-water mixtures. However, the PTMSP membranes indicate initial promise of increased fouling resistance
in operation with cell-containing fermentation broths. 相似文献
82.
The complexity of different quality standards can, in principle, be covered by different approaches and strategies. In-depth
process mapping of quality control (QC) work streams was used by the analytical laboratories of Lonza AG to show up the principle
differences in being compliant to different quality systems. The results identified two main drivers for all necessary actions:
process-related activities and infrastructure-related activities. In addition, a clear indication of the economic impact of
these driving forces was gained, which led the laboratories to decide on a process-oriented approach. This approach has the
advantage of being able to reflect the different demands of different quality assurance (QA) regulations within the same QC
organizational structure. Following the process helps avoid unnecessary efforts in analytical work and represents a very economical
approach, at the same time, providing high flexibility to react to different QA or customer demands.
Received: 5 July 2002 Accepted: 12 November 2002
Acknowledgements The process-oriented approach resulted from many, very challenging discussions for which I would like to thank the staff
of my organization (Analytics & QC), especially, the QA staff and the LIMS team.
Presented at Analytica Conference, 23–26 April 2002, Munich, Germany
Correspondence to B. Ciommer 相似文献
83.
Corrado Di Natale Manuela Zude-SasseAntonella Macagnano Roberto PaolesseBernd Herold Arnaldo D’Amico 《Analytica chimica acta》2002,459(1):107-117
Visual aspect and aroma are among the most important features of fruit that determine consumer preferences. Electronic nose and spectroscopic techniques have shown positive results in evaluating some basic analytical parameters of fruit and global features such as the cultivar.In this paper, we illustrate and discuss a study aimed at evaluating the improvement derived by the fusion of visible spectra and electronic nose data. These experiments were performed on a population of yellow peaches belonging to two cultivars. Each sample was measured by visible optical spectroscopy and by electronic nose. In addition, a number of reference parameters were also measured by conventional destructive methodologies.Collected data were analysed individually and then fused together in order to classify the two cultivars and to estimate the reference parameters. Data fusion was performed building the outer product matrix for each measurement. The set of matrices was then successively unfolded and analysed by conventional chemometrics tools.Results were improved using outer products, for instance in classification average percentage errors of 25, 10, and 7 for electronic nose, spectra, and outer product, respectively was achieved. Regression analysis provides the evidence of a substantial orthogonal appearance of the datasets, which offer former hidden information on fruit classification. 相似文献
84.
Alessandro Lezzi Sandra Cobianco Arnaldo Roggero 《Journal of polymer science. Part A, Polymer chemistry》1994,32(10):1877-1883
A series of chelating resins, derived from a macroreticular styrene-divinylbenzene (2%) copolymer beads grafted with various poly(ethylene glycols) HO? (? CH2? CH2? O? )n? H(n = 0, 4, 9, 13) and containing thiol groups as chelating functions, have been synthesized in a three-step reaction sequence. The structure of the functionalized resins was confirmed by IR spectrophotometry, elemental analysis, and differential scanning calorimetry. The complexation behavior of these thiol resins was investigated towards Hg(II), Cu(II), and Pb(II) ions in aqueous solution by a batch equilibration technique. The influence of pH on adsorption capacity was also examined. The adsorption values for metal ions' intake followed the order Hg(II) > Cu(II) > Pb(II). The affinity of these polymers towards Hg(II) ions was so high that the total mercury level in the liquid decreased from 20 ppm to below 10 ppb after 2 h of treatment. Polymers can be regenerated by washing with a solution of hydrochloric acid (6N) and 10% by weight of an aqueous solution of thiourea. © 1994 John Wiley & Sons, Inc. 相似文献
85.
通过仿真计算分析了激光在光束控制系统通道内传输所产生的热效应及其对远场光束质量的影响。激光传播由近轴波方程描述,用快速傅里叶变换技术求解;激光热效应引起的流场密度变化采用完全Navier-Stokes方程计算。计算给出了不同波长、不同吸收系数条件下的远场光斑情况。计算结果表明,在典型的工作条件和状态下,较高能量激光在光束控制系统通道内产生的热效应影响不容忽视,它会明显降低远场目标处的能量集中度,增大光斑的发散。 相似文献
86.
87.
Andrey G. Kazakov Taisya Y. Ekatova Julia S. Babenya Sergey S. Belyshev Vadim V. Khankin Alexander A. Kuznetsov Sergey E. Vinokurov Boris F. Myasoedov 《Molecules (Basel, Switzerland)》2022,27(10)
A new method of production of one of the most widely used isotopes in nuclear medicine, 177Lu, with high chemical purity was developed; this method includes irradiation of the HfO2 target with bremsstrahlung photons. The irradiated target was dissolved in HF and then diluted and placed onto a column filled with LN resin. Quantitative sorption of 177Lu could be observed during this process. The column later was rinsed with the mixture of 0.1 M HF and 1 M HNO3 and then 2 M HNO3 to remove impurities. Quantitative desorption of 177Lu was achieved by using 6 M HNO3. The developed method of 177Lu production ensures high purification of this isotope from macroquantities of hafnium and zirconium and radioactive impurities of carrier-free yttrium. The content of 177mLu in 177Lu in photonuclear production was determined. Due to high chemical and radionuclide purity, 177Lu obtained by the developed method can be used in nuclear medicine. 相似文献
88.
Mahesh Attimarad Katharigatta Narayanaswamy Venugopala Muhammad S. Chohan Marysheela David Efren II Plaza Molina Nagaraja Sreeharsha Anroop Balachandran Nair Christophe Tratrat Abdulrahman Ibrahim Altaysan Abdulmalek Ahmed Balgoname 《Molecules (Basel, Switzerland)》2022,27(10)
A rapid and reproducible hydrophilic liquid chromatography (HILIC) process was established for concomitant determination of remogliflozin etabonate (RE), vildagliptin (VD), and metformin (MF) in a formulation. A face-centered central composite experimental design was employed to optimize and predict the chromatographic condition by statistically studying the surface response model and design space with desirability close to one. A HILIC column with a simple mobile phase of acetonitrile (65% v/v) and 20 mM phosphate buffer (35% v/v, pH 6, controlled with orthophosphoric acid) was used to separate RE, VD, and MF. RE, VD, and MF were separated in 3.6 min using an isocratic mode mobile phase flow at a flow rate of 1.4 mL at room temperature, and the analytes were examined by recording the absorption at 210 nm. The developed HILIC method was thoroughly validated for all parameters recommended by ICH, and linearity was observed in the ranges 20–150 µg/mL, 10–75 µg/mL, and 50–750 µg/mL for RE, VD, and MF, respectively, along with excellent regression coefficients (r2 > 0.999). The calculated percentage relative deviation and relative error ascertained the precision and accuracy of the method. The selectivity and accuracy were further confirmed by the high percentage recovery of added standard drugs to the formulation using the standard addition technique. The robustness of the HILIC processes was confirmed by developing a half-normal probability plot and Pareto chart, as the slight variation of a single factor had no significant influence on the assay outcomes. Utilization of the optimized HILIC procedure for concurrent quantification of RE, VD, and MF in solid dosage forms showed accurate and reproducible results. Hence, the fast HILIC method can be regularly employed for the quality assurance of pharmaceutical preparations comprising RE, VD, and MF. 相似文献
89.
基于主成分原理的多元质量控制图的构造 总被引:2,自引:1,他引:1
控制图是从事统计质量管理经常使用的重要工具,经过多年的发展和实践,一元质量控制图业已得到普遍推广,可是如何开展多元质量控制仍有许多问题值得探讨。在这篇文章中,我们着重讨论了基于主成分分析的多元质量控制图的构造,并结合从企业现场采集到的数据给出了具体的应用说明。 相似文献
90.
高等院校概率论数理统计课程分级教学的实践与思考 总被引:2,自引:1,他引:1
系统介绍了我校概率论数理统计课程分级教学的改革实践与经验,深入分析了目前存在的主要问题,并初步探讨了构建合理的分级教学模式、全面提高教学质量的关键因素及解决途径. 相似文献