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Extraction Data (extraction + data)
Selected AbstractsAnalysis of Soil Vapor Extraction Data to Evaluate Mass-Transfer Constraints and Estimate Source-Zone Mass FluxGROUND WATER MONITORING & REMEDIATION, Issue 3 2010Mark L. Brusseau Methods are developed to use data collected during cyclic operation of soil vapor extraction (SVE) systems to help characterize the magnitudes and time scales of mass flux associated with vadose zone contaminant sources. Operational data collected at the Department of Energy's Hanford site are used to illustrate the use of such data. An analysis was conducted of carbon tetrachloride vapor concentrations collected during and between SVE operations. The objective of the analysis was to evaluate changes in concentrations measured during periods of operation and nonoperation of SVE, with a focus on quantifying temporal dynamics of the vadose zone contaminant mass flux, and associated source strength. Three mass flux terms, representing mass flux during the initial period of an SVE cycle, during the asymptotic period of a cycle, and during the rebound period, were calculated and compared. It was shown that it is possible to use the data to estimate time frames for effective operation of an SVE system if a sufficient set of historical cyclic operational data exists. This information could then be used to help evaluate changes in SVE operations, including system closure. The mass flux data would also be useful for risk assessments of the impact of vadose zone sources on groundwater contamination or vapor intrusion. [source] Simulation and optimization of supercritical fluid purification of phytosterol estersAICHE JOURNAL, Issue 4 2009Tiziana Fornari Abstract Supercritical carbon dioxide extraction to separate phytosterol esters from fatty acid esters and tocopherols was simulated and optimized using the group contribution equation of state. Experimental extraction data at 328 K, pressures ranging from 200 to 280 bar and solvent-to-feed ratio around 25, was employed to verify the performance of the thermodynamic model. The raw material is the product obtained after a two-step enzymatic reaction carried out on soybean oil deodorizer distillates, and contains mainly fatty-acid ethyl esters, tocopherols and phytosterol esters. The extraction process was simulated using model substances to represent the complex multicomponent feed material. Nonlinear programming techniques were applied to find out optimal process conditions for a steady-state countercurrent process with partial reflux of the extract. The process optimization procedure predicts that a product with 94.2 wt % of phytosterol ester purity and 80% yield could be achieved. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Pacemaker and Defibrillator Lead Extraction: Predictors of Mortality during Follow-UpPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2010SHOAIB HAMID M.D. Background:Extraction of cardiac implantable electric devices is an accepted procedure when systems become infected or malfunction. However, there is an associated morbidity and mortality. We report our 5-year experience and identify predictors of mortality, and long-term follow-up. Methods:We analyzed extraction data from January 2003 to November 2007. Extraction methods used were: locking stylets, telescoping sheaths ± laser, and femoral work stations. Results:One hundred and eighty-three cases were referred, aged 65 ± 16 years (range 28,83); 76% were males. Mean implant time was 75 months (range 4,312 months) and indications were: pocket infection (48%), nonfunctioning lead (22%), erosion through skin (18%), endocarditis/septicemia (11%), bilateral superior vena cava thrombosis (0.5%), and painful lead (0.5%). The number of leads extracted were 369, with complete removal in 90.7% and partial in 7.6%. There were no intraoperative deaths but five (2.7%) died within the same admission as their extraction from overwhelming sepsis. Twelve deaths (6.6%) occurred during an average follow-up of 965 days (range 40,1670). Multivariate logistic regression demonstrated that C-reactive protein preprocedure was predictive of acute in-hospital mortality. Conclusions:Intravascular lead extraction is a safe and efficient method of removing leads. However, there is a subgroup of patients with systemic sepsis with raised inflammatory markers who are at high risk of in-hospital mortality. Long-term follow-up demonstrates mortality which is a marker of the underlying etiology for device implantation, with heart failure patients particularly at risk. (PACE 2010; 33:209,216) [source] Modelling approaches to compare sorption and degradation of metsulfuron-methyl in laboratory micro-lysimeter and batch experimentsPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 12 2003Maik Heistermann Abstract Results of laboratory batch studies often differ from those of outdoor lysimeter or field plot experiments,with respect to degradation as well as sorption. Laboratory micro-lysimeters are a useful device for closing the gap between laboratory and field by both including relevant transport processes in undisturbed soil columns and allowing controlled boundary conditions. In this study, sorption and degradation of the herbicide metsulfuron-methyl in a loamy silt soil were investigated by applying inverse modelling techniques to data sets from different experimental approaches under laboratory conditions at a temperature of 10 °C: first, batch-degradation studies and, second, column experiments with undisturbed soil cores (28 cm length × 21 cm diameter). The column experiments included leachate and soil profile analysis at two different run times. A sequential extraction method was applied in both study parts in order to determine different binding states of the test item within the soil. Data were modelled using ModelMaker and Hydrus-1D/2D. Metsulfuron-methyl half-life in the batch-experiments (t1/2 = 66 days) was shown to be about four times higher than in the micro-lysimeter studies (t1/2 about 17 days). Kinetic sorption was found to be a significant process both in batch and column experiments. Applying the one-rate-two-site kinetic sorption model to the sequential extraction data, it was possible to associate the stronger bonded fraction of metsulfuron-methyl with its kinetically sorbed fraction in the model. Although the columns exhibited strong significance of multi-domain flow (soil heterogeneity), the comparison between bromide and metsulfuron-methyl leaching and profile data showed clear evidence for kinetic sorption effects. The use of soil profile data had significant impact on parameter estimates concerning sorption and degradation. The simulated leaching of metsulfuron-methyl as it resulted from parameter estimation was shown to decrease when soil profile data were considered in the parameter estimation procedure. Moreover, it was shown that the significance of kinetic sorption can only be demonstrated by the additional use of soil profile data in parameter estimation. Thus, the exclusive use of efflux data from leaching experiments at any scale can lead to fundamental misunderstandings of the underlying processes. Copyright © 2003 Society of Chemical Industry [source] | ||||||||||