The Optimal Implementation of On-Line Optimization for Chemical and Refinery Processes.

On-line optimization is an effective approach for process operation and economic improvement and source reduction in chemical and refinery processes. On-line optimization involves three steps of work as: data validation, parameter estimation, and economic optimization. This research evaluated statistical algorithms for gross error detection, data reconciliation, and parameter estimation, and developed an open-form steady state process model for the Monsanto designed sulfuric acid process of IMC Agrico Company. The plant model was used to demonstrate improved economics and reduced emissions from on-line optimization and to test the methodology of on-line optimization. Also, a modified compensation strategy was proposed to improve the misrectification of data reconciliation algorithms and it was compared with measurement test method. In addition, two ways to conduct on-line optimization were studied. One required two separated optimization problems to update parameters, and the other combined data validation and parameter estimation into one optimization problem. Two-step estimation demonstrated a better performance in estimation accuracy than one-step estimation for sulfuric acid process, while one-step estimation required less computation time. The measurement test method, Tjoa-Biegler\u27 contaminated Gaussian distribution method, and robust method were evaluated theoretically and numerically to compare the performance of these methods. Results from these evaluation were used to recommend the best way to conduct on-line optimization. The optimal procedure is to conduct combined gross error detection and data reconciliation to detect and rectify gross errors in plant data from DCS using Tjoa-Biegler\u27s method or robust method. This step generates a set of measurements containing only random errors which is used for simultaneous data reconciliation and parameter estimation using the least squares method (the normal distribution). Updated parameters are used in the plant model for economic optimization that generates optimal set points for DCS. Applying this procedure to the Monsanto sulfuric acid plant had an increased profit of 3% over current operating condition and an emission reduction of 10% which is consistent with other reported applications. Also, this optimal procedure to conduct on-line optimization has been incorporated into an interactive on-line optimization program which used a window interface developed with Visual Basic and GAMS to solve the nonlinear optimization problems. This program is to be available through the EPA Technology Tool Program

Extension and parameterization of high-order density dependence in Skyrme forces

The three-body force is indispensable in nuclear energy density functionals which leads to a density dependent two-body term in the Hartree-Fock approach. Usually a single factional power of density dependency has been adopted. We consider the possibility of an additional higher-order density dependence in extended Skyrme forces. As a result, new extended Skyrme parametertizations based on the SLy4 force are obtained and the improvements in descriptions of global nuclei have been demonstrated. The higher-order term can also substantially affect nuclear properties in the high density region in general ways.Comment: 6 pages, 5 figure

Comparison of Functional and Cognitive Capacity Among Cancer Survivors and Cancer-free Individuals in an Older US population

Background The global population is aging rapidly, and cancer is one of the major health concerns of an aging population. Older cancer survivors can be challenged by the toxicities associated with cancer and its treatment in addition to the normal declines in functional and cognitive capacities due to aging. However, we only have limited data on whether older cancer survivors have worse functional and cognitive capacity profiles than their cancer-free counterparts. Method For this study, 7,459 participants from Health and Retirement Study (HRS) and completed functional capacity questionnaire between Feb 2016 to April 2018 were included, among which 1,238 are cancer survivors, and the rest are cancer-free. Answers from biennial HRS questionnaires were used for exposure and outcome ascertainment. Poisson regression models with robust variance were used to estimate the risk ratio (RR) for the association between cancer history and prevalence of functional and cognitive limitation. Stratified analysis by race/ethnicity was performed to explore potential race/ethnic group differences. Sensitivity analyses excluding demented participants were performed to evaluate the reliability of the primary analyses. Results A significant positive association was observed between cancer history and any disability in basic ADLs (adjusted Risk Ratio = 1.09, 95% CI (1.01, 1.18). A significant positive association was observed between cancer history and any disability in IADLs (adjusted Risk Ratio = 1.11 (1.02, 1.22). Cognitive capacity did not differ significantly between cancer survivors and cancer-free participants. Low educational level, depressive symptoms within 12-month, and dementia history may also contribute to poor functional and cognitive capacities. Stratified analyses showed that non-Hispanic white has similar results to the analytic population. Because of group size, other race/ethnic groups do not show statistically significant associations, but the point estimate directions are similar to the analytic population except for gender. Sensitivity analysis results were similar to that of the primary analysis. Conclusion Older U.S. individuals with cancer history have reduced functional capacities but not cognitive capacity compared to older U.S. individuals without cancer history. More research is needed to study these differences and how to improve older cancer survivors’ functional capacity, therefore optimizing health in elderly cancer survivors

Microstructure and morphological characterization of lead-contaminated clay with nanoscale zero-valent iron (nZVI) treatment

The increasing use of nanoscale zero-valent iron (nZVI) for soil and groundwater remediation has raised concerns about its potential effect on soil properties. Numerous laboratory and field studies have demonstrated its excellent capability to immobilize contaminants and enhance contaminated soil. However, a few studies have shed light on the changes in the microstructure and morphology of the soil due to nZVI treatment. This study explores the variation in particle morphology and microstructure in nZVI-treated soil. A series of microscale experiments, including field emission scanning electron microscopy (FESEM), particle size analysis, mercury injection porosimetry (MIP), optical microscopic analysis, and particle shape tests, were conducted on nZVI-treated samples. The dosages of nZVI used were 0%, 0.2%, 1%, 5%, and 10% of the contaminated soil. Morphological characterization suggested that the addition of nZVI resulted in the occurrence of larger-sized particles, on-particle branched structures, finer pore size distribution, aggregation, and a flocculent network in the soil structure. The aggregated and bonded soil particles via nZVI could be one of the mechanisms for its variation in geotechnical characteristics. The findings of this study may improve our understanding of soil improvement using nZVI treatment

Simultaneous stabilization of Pb and improvement of soil strength using nZVI

This study demonstrates the feasibility of nanoscale Zero-Valent Iron (nZVI) for simultaneous stabilization of Pb and improvement of soil strength via batch experiments. The soil samples were prepared using slurry and pre-consolidation method at nZVI doses of 0.2%, 1%, 5%, and 10% (by dry weight). The physicochemical and geotechnical properties of Pb-contaminated soil treated by nZVI were analyzed. The results indicate that the contamination of Pb(II) resulted in a notable reduction in the undrained shear strength of soil from 16.85 kPa to 7.25 kPa. As expected, the Pb in exchangeable and carbonate-bound fractions decreased significantly with the increasing doses of nZVI. Meanwhile, the undrained shear strength of Pb-contaminated soil enhanced substantially as the increase of nZVI, from 25.83 kPa (0.2% nZVI treatment) to 69.33 kPa (10% nZVI treatment). An abundance of bubbles, generated from the oxidation of nZVI, was recorded. The mechanisms for simultaneous stabilization of Pb and soil improvement primarily include: 1) the precipitation and transformation of Pb-/Fe-hydrated oxides on the soil particles and their induced bounding effects; 2) the increased drainage capability of soil as the occupation of nZVI aggregates and bubbles in the macropores space and 3) the lower soil density derived from the increase in microbubbles retained in the soil. This study is provided to facilitate the application of nZVI in the redevelopment of contaminated soil

On the use of reduced basis methods to accelerate and stabilize the Parareal method

We propose a modified parallel-in-time - Parareal - multi-level time integration method which, in contrast to previous methods, uses a coarse solver based on the information from the fine solver at each iteration through the construction of a reduced model. This approach is demonstrated to offer two substantial advantages: it accelerates convergence of the original parareal method and we furthermore demonstrate that the reduced basis stabilizes the parareal method for purely advective problems where instabilities are known to arise. When combined with empirical interpolation techniques (EIM), we discuss the use of this approach to solve both linear and nonlinear problems and highlight the minimal changes required to utilize this algorithm to accelerate existing implementations. We illustrate advantages through the algorithmic design, through analysis of stability, convergence, and computational complexity, and through several numerical examples

Experimental study of the usage of combined biopolymer and plants in reinforcing the clayey soil exposed to acidic and alkaline contaminations

In the last decade, biopolymers have been extensively studied, showing a great potential in soil reinforcement and the promotion of vegetation growth with limited environmental impact. In this paper, a soil reinforcing method with combined biopolymer (xanthan gum, XG) and plants (oat) was proposed to strengthen the clayey soil with different pore fluid pH values. A series of laboratory tests were conducted, mainly including the plant cultivation tests and the direct shear tests. It was found that oats grew better in the neutral, weakly acidic, and weakly alkaline soil environments. Both 0.25% XG and 0.50% XG that mostly promoted plant growth, also led to higher soil shear strength. An excessive XG content (e.g., 0.75% and 1.00%) may lead to the formation of a hard XG–soil matrix, preventing oat growth and therefore resulting in a lower shear strength. The XG–oat combination was found to be more effective in treating the soils with acidic pH values. Furthermore, the XG–oat combination is able to reduce the types and contents of heavy metal elements in the soil. Therefore, we suggest using biopolymers in combination with plants to improve the stability and geotechnical performances of the shallow soil slopes that are exposed to acidic and alkaline contamination

Effects of Billet-Making Methods on Volatile Flavor Components of Sanhua Plum Fruit Billets Based on Headspace-Gas Chromatography-Ion Mobility Spectroscopy and Electronic Nose

In order to investigate the effect of billet-making methods on the volatile components of the Sanhua plum fruit billets, electronic nose and headspace-gas chromatography-ion mobility spectroscopy (HS-GC-IMS) were used to analyze and compare the volatile components of four groups of samples of salt cured, sulfite mixed salt cured, lactic acid bacteria fermented fruit billets and fresh fruit control. The results showed that both the electronic nose linear discriminant analysis (LDA) and the principal component analysis based on the HS-GC-IMS assay results clearly distinguished the four groups of samples, the flavor characteristics of fresh fruits were significantly changed after different curing treatments, and the differences among fruit blanks samples were significant. HS-GC-IMS detected and identified a total of 49 volatile compounds in four groups of samples, and the high relative contents were mainly alcohols, esters and aldehydes. The relative odor activity value (ROAV) showed significant differences in key flavor substances among the three fruit billets, the lactic acid fermented fruit billet had the highest total peak volume of volatile flavor substances (194760) and the most types of key flavor substances (10), mainly short-chain aldehydes. From the perspective of flavor richness of fruit billets, the flavor quality of fruit billet by lactic acid fermentation was considered to be better. The results of this study provided an useful reference for the selection of the billet-making methods of Sanhua plums

Certified reduced basis method for electromagnetic scattering and radar cross section estimation

We study nontrivial applications of the reduced basis method (RBM) for electromagnetic applications with an emphasis on scattering and the estimation of radar cross section (RCS). The method and several extensions are explained with two examples with different characteristics. Parameters that are allowed to vary within the model include frequency, incident angle and measurement angle as well as the geometry of the scatterers. With appropriate applications of the empirical interpolation method (EIM), transformation of the domain, configuration of perfectly matched layer, exponential convergence of the reduced basis solution over the entire parameter domain is achieved. Moreover, we demonstrate that this approach allows for the effective capture of the critical behavior, in this case through shapes that minimize scattering. This further highlights the robustness and quality of the greedy approximation and the reduced basis method approach. (C) 2012 Elsevier B.V. All rights reserved