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Sample records for critical solvents optimization

  1. Criticality safety of solvent extraction process

    International Nuclear Information System (INIS)

    Tachimori, Shoichi; Miyoshi, Yoshinori

    1987-01-01

    The article presents some comments on criticality safety of solvent extraction processes. When used as an extracting medium, tributyl phosphate extracts nitric acid and water, in addition to nitrates of U and Pu, into the organic phase. The amount of these chemical species extracted into the organic phase is dependent on and restricted by the concentrations of tributyl phosphate and other components. For criticality control, measures are taken to decrease the concentration of tributyl phosphate in the organic phase, in addition to control of the U and Pu concentrations in the feed water phase. It should be remembered that complexes of tributyl phosphate with nitrates of such metals as Pu(IV), Pu(VI), U(IV) and Th(IV) do not dissolve uniformly in the organic phase. In criticality calculation for solution-handling systems, U and Pu are generally assumed to have a valence of 6 and 4, respectively. In the reprocessing extraction process, however, U and Pu can have a valence of 4, and 3 and 6, respectively. The organic phase and aqueous phase contact in a counter-current flow. U and Pu will be accumulated if they are not brought out of the extraction system by this flow. (Nogami, K.)

  2. Caustic-Side Solvent Extraction: Chemical and Physical Properties of the Optimized Solvent

    Energy Technology Data Exchange (ETDEWEB)

    Delmau, L.H.

    2002-10-08

    This work was undertaken to optimize the solvent used in the Caustic Side Solvent Extraction (CSSX) process and to measure key chemical and physical properties related to its performance in the removal of cesium from the alkaline high-level salt waste stored in tanks at the Savannah River Site. The need to adjust the solvent composition arose from the prior discovery that the previous baseline solvent was supersaturated with respect to the calixarene extractant. The following solvent-component concentrations in Isopar{reg_sign} L diluent are recommended: 0.007 M calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) extractant, 0.75 M 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) phase modifier, and 0.003 M tri-n-octylamine (TOA) stripping aid. Criteria for this selection included BOBCalixC6 solubility, batch cesium distribution ratios (D{sub Cs}), calculated flowsheet robustness, third-phase formation, coalescence rate (dispersion numbers), and solvent density. Although minor compromises within acceptable limits were made in flowsheet robustness and solvent density, significant benefits were gained in lower risk of third-phase formation and lower solvent cost. Data are also reported for the optimized solvent regarding the temperature dependence of D{sub Cs} in extraction, scrubbing, and stripping (ESS); ESS performance on recycle; partitioning of BOBCalixC6, Cs-7SB, and TOA to aqueous process solutions; partitioning of organic anions; distribution of metals; solvent phase separation at low temperatures; solvent stability to elevated temperatures; and solvent density and viscosity. Overall, the technical risk of the CSSX process has been reduced by resolving previously identified issues and raising no new issues.

  3. Critical Casimir effect in a polymer chain in supercritical solvents.

    Science.gov (United States)

    Sumi, Tomonari; Imazaki, Nobuyuki; Sekino, Hideo

    2009-03-01

    Density fluctuation effects on the conformation of a polymer chain in a supercritical solvent were investigated by performing a multiscale simulation based on the density-functional theory. We found (a) a universal swelling of the polymer chain near the critical point, irrespective of whether the polymer chain is solvophilic or solvophobic, and (b) a characteristic collapse of the polymer chain having a strong solvophilicity at a temperature slightly higher than the critical point, where the isothermal compressibility becomes less than the ideal one.

  4. Optimization of the GBMV2 implicit solvent force field for accurate simulation of protein conformational equilibria.

    Science.gov (United States)

    Lee, Kuo Hao; Chen, Jianhan

    2017-06-15

    Accurate treatment of solvent environment is critical for reliable simulations of protein conformational equilibria. Implicit treatment of solvation, such as using the generalized Born (GB) class of models arguably provides an optimal balance between computational efficiency and physical accuracy. Yet, GB models are frequently plagued by a tendency to generate overly compact structures. The physical origins of this drawback are relatively well understood, and the key to a balanced implicit solvent protein force field is careful optimization of physical parameters to achieve a sufficient level of cancellation of errors. The latter has been hampered by the difficulty of generating converged conformational ensembles of non-trivial model proteins using the popular replica exchange sampling technique. Here, we leverage improved sampling efficiency of a newly developed multi-scale enhanced sampling technique to re-optimize the generalized-Born with molecular volume (GBMV2) implicit solvent model with the CHARMM36 protein force field. Recursive optimization of key GBMV2 parameters (such as input radii) and protein torsion profiles (via the CMAP torsion cross terms) has led to a more balanced GBMV2 protein force field that recapitulates the structures and stabilities of both helical and β-hairpin model peptides. Importantly, this force field appears to be free of the over-compaction bias, and can generate structural ensembles of several intrinsically disordered proteins of various lengths that seem highly consistent with available experimental data. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Polymer models with optimal good-solvent behavior

    Science.gov (United States)

    D'Adamo, Giuseppe; Pelissetto, Andrea

    2017-11-01

    We consider three different continuum polymer models, which all depend on a tunable parameter r that determines the strength of the excluded-volume interactions. In the first model, chains are obtained by concatenating hard spherocylinders of height b and diameter rb (we call them thick self-avoiding chains). The other two models are generalizations of the tangent hard-sphere and of the Kremer-Grest models. We show that for a specific value r* , all models show optimal behavior: asymptotic long-chain behavior is observed for relatively short chains. For r < r* , instead, the behavior can be parametrized by using the two-parameter model, which also describes the thermal crossover close to the θ point. The bonds of the thick self-avoiding chains cannot cross each other, and therefore the model is suited for the investigation of topological properties and for dynamical studies. Such a model also provides a coarse-grained description of double-stranded DNA, so that we can use our results to discuss under which conditions DNA can be considered as a model good-solvent polymer.

  6. Optimizing Reasonableness, Critical Thinking, and Cyberspace

    Science.gov (United States)

    Ikuenobe, Polycarp

    2003-01-01

    In this paper, the author argues that the quantity, superabundance of information, easy availability, and quick access to information in cyberspace may engender critical thinking and the optimization of reasonableness. This point is different from, but presupposes, the commonplace view that critical thinking abilities, criteria, processes, and…

  7. Density Changes in the Optimized CSSX Solvent System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.D.

    2002-11-25

    Density increases in caustic-side solvent extraction (CSSX) solvent have been observed in separate experimental programs performed by different groups of researchers. Such changes indicate a change in chemical composition. Increased density adversely affects separation of solvent from denser aqueous solutions present in the CSSX process. Identification and control of factors affecting solvent density are essential for design and operation of the centrifugal contactors. The goals of this research were to identify the factors affecting solvent density (composition) and to develop correlations between easily measured solvent properties (density and viscosity) and the chemical composition of the solvent, which will permit real-time determination and adjustment of the solvent composition. In evaporation experiments, virgin solvent was subjected to evaporation under quiescent conditions at 25, 35, and 45 C with continuously flowing dry air passing over the surface of the solvent. Density and viscosity were measured periodically, and chemical analysis was performed on the solvent samples. Chemical interaction tests were completed to determine if any chemical reaction takes place over extended contact time that changes the composition and/or physical properties. Solvent and simulant, solvent and strip solution, and solvent and wash solution were contacted continuously in agitated flasks. They were periodically sampled and the density measured (viscosity was also measured on some samples) and then submitted to the Chemical Sciences Division of Oak Ridge National Laboratory for analysis by nuclear magnetic resonance (NMR) spectrometry and high-performance liquid chromatography (HPLC) using the virgin solvent as the baseline. Chemical interaction tests showed that solvent densities and viscosities did not change appreciably during contact with simulant, strip, or wash solution. No effects on density and viscosity and no chemical changes in the solvent were noted within

  8. Process optimization for inkjet printing of triisopropylsilylethynyl pentacene with single-solvent solutions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xianghua, E-mail: xhwang@hfut.edu.cn [Key Lab of Special Display Technology, Ministry of Education, National Engineering Lab of Special Display Technology, National Key Lab of Advanced Display Technology, Academy of Opto-Electronic Technology, Hefei University of Technology, Hefei 230009 (China); Yuan, Miao [Key Lab of Special Display Technology, Ministry of Education, National Engineering Lab of Special Display Technology, National Key Lab of Advanced Display Technology, Academy of Opto-Electronic Technology, Hefei University of Technology, Hefei 230009 (China); School of Electronic Science & Applied Physics, Hefei University of Technology, Hefei 230009 (China); Xiong, Xianfeng; Chen, Mengjie [Key Lab of Special Display Technology, Ministry of Education, National Engineering Lab of Special Display Technology, National Key Lab of Advanced Display Technology, Academy of Opto-Electronic Technology, Hefei University of Technology, Hefei 230009 (China); Qin, Mengzhi [Key Lab of Special Display Technology, Ministry of Education, National Engineering Lab of Special Display Technology, National Key Lab of Advanced Display Technology, Academy of Opto-Electronic Technology, Hefei University of Technology, Hefei 230009 (China); School of Electronic Science & Applied Physics, Hefei University of Technology, Hefei 230009 (China); Qiu, Longzhen; Lu, Hongbo; Zhang, Guobing; Lv, Guoqiang [Key Lab of Special Display Technology, Ministry of Education, National Engineering Lab of Special Display Technology, National Key Lab of Advanced Display Technology, Academy of Opto-Electronic Technology, Hefei University of Technology, Hefei 230009 (China); Choi, Anthony H.W. [Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong (China)

    2015-03-02

    Inkjet printing of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-PEN), a small molecule organic semiconductor, is performed on two types of substrates. Hydrophilic SiO{sub 2} substrates prepared by a combination of surface treatments lead to either a smaller size or a coffee-ring profile of the single-drop film. A hydrophobic surface with dominant dispersive component of surface energy such as that of a spin-coated poly(4-vinylphenol) film favors profile formation with uniform thickness of the printed semiconductor owing to the strong dispersion force between the semiconductor molecules and the hydrophobic surface of the substrate. With a hydrophobic dielectric as the substrate and via a properly selected solvent, high quality TIPS-PEN films were printed at a very low substrate temperature of 35 °C. Saturated field-effect mobility measured with top-contact thin-film transistor structure shows a narrow distribution and a maximum of 0.78 cm{sup 2}V{sup −1} s{sup −1}, which confirmed the film growth on the hydrophobic substrate with increased crystal coverage and continuity under the optimized process condition. - Highlights: • Hydrophobic substrates were employed to inhibit the coffee-ring effect. • Contact-line pinning is primarily controlled by the dispersion force. • Solvent selection is critical to crystal coverage of the printed film. • High performance and uniformity are achieved by process optimization.

  9. Optimization of soy isoflavone extraction with different solvents using the simplex-centroid mixture design.

    Science.gov (United States)

    Yoshiara, Luciane Yuri; Madeira, Tiago Bervelieri; Delaroza, Fernanda; da Silva, Josemeyre Bonifácio; Ida, Elza Iouko

    2012-12-01

    The objective of this study was to optimize the extraction of different isoflavone forms (glycosidic, malonyl-glycosidic, aglycone and total) from defatted cotyledon soy flour using the simplex-centroid experimental design with four solvents of varying polarity (water, acetone, ethanol and acetonitrile). The obtained extracts were then analysed by high-performance liquid chromatography. The profile of the different soy isoflavones forms varied with different extractions solvents. Varying the solvent or mixture used, the extraction of different isoflavones was optimized using the centroid-simplex mixture design. The special cubic model best fitted to the four solvents and its combination for soy isoflavones extraction. For glycosidic isoflavones extraction, the polar ternary mixture (water, acetone and acetonitrile) achieved the best extraction; malonyl-glycosidic forms were better extracted with mixtures of water, acetone and ethanol. Aglycone isoflavones, water and acetone mixture were best extracted and total isoflavones, the best solvents were ternary mixture of water, acetone and ethanol.

  10. Optimal (Solvent) Mixture Design through a Decomposition Based CAMD methodology

    DEFF Research Database (Denmark)

    Achenie, L.; Karunanithi, Arunprakash T.; Gani, Rafiqul

    2004-01-01

    Computer Aided Molecular/Mixture design (CAMD) is one of the most promising techniques for solvent design and selection. A decomposition based CAMD methodology has been formulated where the mixture design problem is solved as a series of molecular and mixture design sub-problems. This approach is...

  11. Estimation of the Critical Temperatures of Some More Deep Eutectic Solvents from Their Surface Tensions

    Directory of Open Access Journals (Sweden)

    Yizhak Marcus

    2018-01-01

    Full Text Available The critical temperatures of two dozen deep eutectic solvents, for only some of which these have been estimated previously, were estimated from the temperature dependences of their surface tensions and densities available in the literature according to the Eötvös and the Guggenheim expressions.

  12. Optimization of a flow injection analysis system for multiple solvent extraction

    International Nuclear Information System (INIS)

    Rossi, T.M.; Shelly, D.C.; Warner, I.M.

    1982-01-01

    The performance of a multistage flow injection analysis solvent extraction system has been optimized. The effect of solvent segmentation devices, extraction coils, and phase separators on performance characteristics is discussed. Theoretical consideration is given to the effects and determination of dispersion and the extraction dynamics within both glass and Teflon extraction coils. The optimized system has a sample recovery similar to an identical manual procedure and a 1.5% relative standard deviation between injections. Sample throughput time is under 5 min. These characteristics represent significant improvements over the performance of the same system before optimization. 6 figures, 2 tables

  13. Optimally Fortifying Logic Reliability through Criticality Ranking

    Directory of Open Access Journals (Sweden)

    Yu Bai

    2015-02-01

    Full Text Available With CMOS technology aggressively scaling towards the 22-nm node, modern FPGA devices face tremendous aging-induced reliability challenges due to bias temperature instability (BTI and hot carrier injection (HCI. This paper presents a novel anti-aging technique at the logic level that is both scalable and applicable for VLSI digital circuits implemented with FPGA devices. The key idea is to prolong the lifetime of FPGA-mapped designs by strategically elevating the VDD values of some LUTs based on their modular criticality values. Although the idea of scaling VDD in order to improve either energy efficiency or circuit reliability has been explored extensively, our study distinguishes itself by approaching this challenge through an analytical procedure, therefore being able to maximize the overall reliability of the target FPGA design by rigorously modeling the BTI-induced device reliability and optimally solving the VDD assignment problem. Specifically, we first develop a systematic framework to analytically model the reliability of an FPGA LUT (look-up table, which consists of both RAM memory bits and associated switching circuit. We also, for the first time, establish the relationship between signal transition density and a LUT’s reliability in an analytical way. This key observation further motivates us to define the modular criticality as the product of signal transition density and the logic observability of each LUT. Finally, we analytically prove, for the first time, that the optimal way to improve the overall reliability of a whole FPGA device is to fortify individual LUTs according to their modular criticality. To the best of our knowledge, this work is the first to draw such a conclusion.

  14. Applications of genetic algorithms to optimization problems in the solvent extraction process for spent nuclear fuel

    International Nuclear Information System (INIS)

    Omori, Ryota, Sakakibara, Yasushi; Suzuki, Atsuyuki

    1997-01-01

    Applications of genetic algorithms (GAs) to optimization problems in the solvent extraction process for spent nuclear fuel are described. Genetic algorithms have been considered a promising tool for use in solving optimization problems in complicated and nonlinear systems because they require no derivatives of the objective function. In addition, they have the ability to treat a set of many possible solutions and consider multiple objectives simultaneously, so they can calculate many pareto optimal points on the trade-off curve between the competing objectives in a single iteration, which leads to small computing time. Genetic algorithms were applied to two optimization problems. First, process variables in the partitioning process were optimized using a weighted objective function. It was observed that the average fitness of a generation increased steadily as the generation proceeded and satisfactory solutions were obtained in all cases, which means that GAs are an appropriate method to obtain such an optimization. Secondly, GAs were applied to a multiobjective optimization problem in the co-decontamination process, and the trade-off curve between the loss of uranium and the solvent flow rate was successfully obtained. For both optimization problems, CPU time with the present method was estimated to be several tens of times smaller than with the random search method

  15. Optimization of solvent extraction of shea butter (Vitellaria paradoxa) using response surface methodology and its characterization.

    Science.gov (United States)

    Ajala, E O; Aberuagba, F; Olaniyan, A M; Onifade, K R

    2016-01-01

    Shea butter (SB) was extracted from its kernel by using n-hexane as solvent in an optimization study. This was to determine the optima operating variables that would give optimum yield of SB and to study the effect of solvent on the physico-chemical properties and chemical composition of SB extracted using n-hexane. A Box-behnken response surface methodology (RSM) was used for the optimization study while statistical analysis using ANOVA was used to test the significance of the variables for the process. The variables considered for this study were: sample weight (g), solvent volume (ml) and extraction time (min). The physico-chemical properties of SB extracted were determined using standard methods and Fourier Transform Infrared Spectroscopy (FTIR) for the chemical composition. The results of RSM analysis showed that the three variables investigated have significant effect (p food, biodiesel production, cosmetics, medicinal and pharmaceutical purposes than shea butter extracted using solvent extraction method (SBS). Fourier Transform Infrared Spectroscopy (FTIR) results obtained for the two samples were similar to what was obtainable from other vegetable oil.

  16. Optimization of flavanones extraction by modulating differential solvent densities and centrifuge temperatures.

    Science.gov (United States)

    Chebrolu, Kranthi K; Jayaprakasha, G K; Jifon, J; Patil, Bhimanagouda S

    2011-07-15

    Understanding the factors influencing flavonone extraction is critical for the knowledge in sample preparation. The present study was focused on the extraction parameters such as solvent, heat, centrifugal speed, centrifuge temperature, sample to solvent ratio, extraction cycles, sonication time, microwave time and their interactions on sample preparation. Flavanones were analyzed in a high performance liquid chromatography (HPLC) and later identified by liquid chromatography and mass spectrometry (LC-MS). The five flavanones were eluted by a binary mobile phase with 0.03% phosphoric acid and acetonitrile in 20 min and detected at 280 nm, and later identified by mass spectral analysis. Dimethylsulfoxide (DMSO) and dimethyl formamide (DMF) had optimum extraction levels of narirutin, naringin, neohesperidin, didymin and poncirin compared to methanol (MeOH), ethanol (EtOH) and acetonitrile (ACN). Centrifuge temperature had a significant effect on flavanone distribution in the extracts. The DMSO and DMF extracts had homogeneous distribution of flavanones compared to MeOH, EtOH and ACN after centrifugation. Furthermore, ACN showed clear phase separation due to differential densities in the extracts after centrifugation. The number of extraction cycles significantly increased the flavanone levels during extraction. Modulating the sample to solvent ratio increased naringin quantity in the extracts. Current research provides critical information on the role of centrifuge temperature, extraction solvent and their interactions on flavanone distribution in extracts. Published by Elsevier B.V.

  17. A new decomposition-based computer-aided molecular/mixture design methodology for the design of optimal solvents and solvent mixtures

    DEFF Research Database (Denmark)

    Karunanithi, A.T.; Achenie, L.E.K.; Gani, Rafiqul

    2005-01-01

    This paper presents a novel computer-aided molecular/mixture design (CAMD) methodology for the design of optimal solvents and solvent mixtures. The molecular/mixture design problem is formulated as a mixed integer nonlinear programming (MINLP) model in which a performance objective is to be optim......This paper presents a novel computer-aided molecular/mixture design (CAMD) methodology for the design of optimal solvents and solvent mixtures. The molecular/mixture design problem is formulated as a mixed integer nonlinear programming (MINLP) model in which a performance objective...... is to be optimized subject to structural, property, and process constraints. The general molecular/mixture design problem is divided into two parts. For optimal single-compound design, the first part is solved. For mixture design, the single-compound design is first carried out to identify candidates...... and then the second part is solved to determine the optimal mixture. The decomposition of the CAMD MINLP model into relatively easy to solve subproblems is essentially a partitioning of the constraints from the original set. This approach is illustrated through two case studies. The first case study involves...

  18. Derivation of Reliable Geometries in QM Calculations of DNA Structures: Explicit Solvent QM/MM and Restrained Implicit Solvent QM Optimizations of G-Quadruplexes.

    Science.gov (United States)

    Gkionis, Konstantinos; Kruse, Holger; Šponer, Jiří

    2016-04-12

    Modern dispersion-corrected DFT methods have made it possible to perform reliable QM studies on complete nucleic acid (NA) building blocks having hundreds of atoms. Such calculations, although still limited to investigations of potential energy surfaces, enhance the portfolio of computational methods applicable to NAs and offer considerably more accurate intrinsic descriptions of NAs than standard MM. However, in practice such calculations are hampered by the use of implicit solvent environments and truncation of the systems. Conventional QM optimizations are spoiled by spurious intramolecular interactions and severe structural deformations. Here we compare two approaches designed to suppress such artifacts: partially restrained continuum solvent QM and explicit solvent QM/MM optimizations. We report geometry relaxations of a set of diverse double-quartet guanine quadruplex (GQ) DNA stems. Both methods provide neat structures without major artifacts. However, each one also has distinct weaknesses. In restrained optimizations, all errors in the target geometries (i.e., low-resolution X-ray and NMR structures) are transferred to the optimized geometries. In QM/MM, the initial solvent configuration causes some heterogeneity in the geometries. Nevertheless, both approaches represent a decisive step forward compared to conventional optimizations. We refine earlier computations that revealed sizable differences in the relative energies of GQ stems computed with AMBER MM and QM. We also explore the dependence of the QM/MM results on the applied computational protocol.

  19. Optimal Furosemide Therapy in Critically Ill infants

    NARCIS (Netherlands)

    M.M.J. van der Vorst

    2007-01-01

    textabstractFurosemide as continuous infusion is used in infants after cardiopulmonary bypass (CPB) surgery and during extracorporeal membrane oxygenation (ECMO). The currently used regimens which start with low dose (0.05 - 0.1 mg/kg.hr) may not be optimal in this group of patients with

  20. Outcomes Related to the Use of Frozen Plasma or Pooled Solvent/Detergent-Treated Plasma in Critically Ill Children

    DEFF Research Database (Denmark)

    Camazine, Maraya N; Karam, Oliver; Colvin, Ryan

    2017-01-01

    OBJECTIVE: To determine if the use of fresh frozen plasma/frozen plasma 24 hours compared to solvent detergent plasma is associated with international normalized ratio reduction or ICU mortality in critically ill children. DESIGN: This is an a priori secondary analysis of a prospective, observati......OBJECTIVE: To determine if the use of fresh frozen plasma/frozen plasma 24 hours compared to solvent detergent plasma is associated with international normalized ratio reduction or ICU mortality in critically ill children. DESIGN: This is an a priori secondary analysis of a prospective....... SETTING: One hundred one PICUs in 21 countries. PATIENTS: All critically ill children admitted to a participating unit were included if they received at least one plasma unit during six predefined 1-week (Monday to Friday) periods. All children were exclusively transfused with either fresh frozen plasma...... was independently associated with reduced ICU mortality (odds ratio, 0.40; 95% CI, 0.16-0.99; p = 0.05). CONCLUSIONS: Solvent detergent plasma use in critically ill children may be associated with improved survival. This hypothesis-generating data support a randomized controlled trial comparing solvent detergent...

  1. Solvent Optimization for Efficient Enzymatic Monoacylglycerol Production Based on a Glycerolysis Reaction

    DEFF Research Database (Denmark)

    Damstrup, Marianne; Jensen, Tine; Sparsø, Flemming V.

    2005-01-01

    This study was aimed at screening solvent systems of varying polarities to identify suitable solvents for efficient and practical enzymatic glycerolysis. Several pure solvents and solvent mixtures were screened in a batch reaction system consisting of glycerol, sunflower oil, and Novozymo (R) 435...

  2. Optimization of nanolime solvent for the consolidation of coarse porous limestone

    Science.gov (United States)

    Borsoi, Giovanni; Lubelli, Barbara; van Hees, Rob; Veiga, Rosário; Silva, António Santos

    2016-09-01

    The potentialities of nanomaterials for application in the field of conservation have been widely investigated in the last two decades. Among nanomaterials, nanolimes, i.e., dispersions of lime nanoparticles in alcohols are promising consolidating products for calcareous materials. Nanolimes are effective in recovering the very superficial loss of cohesion of decayed materials, but they do not always provide sufficient mass consolidation. This limitation is mainly related to the deposition of the nanoparticles nearby the surface of the material. Experimental research has been set up with the aim of improving the in-depth deposition of lime nanoparticles. Previous research by the authors has shown that nanolime deposition within a substrate can be controlled by adapting the nanolimes properties (kinetic stability and evaporation rate) to the moisture transport behavior of the substrate. Nanolime properties can be modified by the use of different solvents. In this research, nanolime dispersions have been further optimized for application on Maastricht limestone, a coarse porous limestone. Firstly, nanolimes were synthesized and dispersed in ethanol and/or water, both pure and mixed in different percentages. Subsequently, based on the kinetic stability of the nanolime dispersions, the most promising solvent mixtures were selected and applied on the limestone. The deposition of lime nanoparticles within the limestone was studied by phenolphthalein test, optical microscopy and scanning electron microscopy. The results confirm that nanolime dispersed in a mixture of ethanol (95 %) and water (5 %) can guarantee a better nanoparticles in-depth deposition within coarse porous substrates, when compared to dispersions in pure ethanol.

  3. The optimal blood glucose level for critically ill adult patients.

    Science.gov (United States)

    Lv, Shaoning; Ross, Paul; Tori, Kathleen

    2017-09-01

    Glycaemic control is recognized as one of the important aspects in managing critically ill patients. Both hyperglycaemia and hypoglycaemia independently increase the risk of patient mortality. Hence, the identification of optimal glycaemic control is of paramount importance in the management of critically ill patients. The aim of this literature review is to examine the current status of glycaemic control in critically ill adult patients. This literature review will focus on randomized controlled trials comparing intensive insulin therapy to conventional insulin therapy, with an objective to identify optimal blood glucose level targets for critically ill adult patients. A literature review was conducted to identify large randomized controlled trials for the optimal targeted blood glucose level for critically ill adult patients published since 2000. A total of eight studies fulfilled the selection criteria of this review. With current human and technology resources, the results of the studies support commencing glycaemic control once the blood glucose level of critically ill patients reaches 10 mmol/L and maintaining this level between 8 mmol/L and 10 mmol/L. This literature review provides a recommendation for targeting the optimal blood glucose level for critically ill patients within moderate blood glucose level target range (8-10 mmol/L). The need for uniformed glucometrics for unbiased reporting and further research for optimal blood glucose target is required, especially in light of new technological advancements in closed-loop insulin delivery and monitoring devices. This literature review has revealed a need to call for consensus in the measurement and reporting of glycaemic control using standardized glucometrics. © 2017 British Association of Critical Care Nurses.

  4. Optimization Study for Butanol Extraction from Butanol-Water Using Fatty Acid Methyl Ester (FAME) as Solvent

    International Nuclear Information System (INIS)

    Nurul Izzati Ab Rahim; Mohd Irfan Hatim Mohamed Dzahir; Wan Nurul Hidayah Wan Othman

    2015-01-01

    The oil crisis, warned the humanity's depends on oil was not sustainable and recently, there are plenty of renewable resources had been developed. Much attention has been given to the solvent extraction process to separate butanol from butanol-water mixture using fatty acid methyl ester (FAME) as a solvent. In this respect, the use of FAME as a green solvent which are locally available has greater potential for butanol extraction process. Therefore, an experimental work has been carried out to study its feasibility as a potential solvent. A single stage extraction process as performed to evaluate the ability to achieve optimal extract butanol. The extraction process was carried out to evaluate the distribution coefficient of butanol with the effects of other parameters such as reaction temperature (50-70 degree Celsius) and butanol-water mixture to solvent ratio (1:1, 1:1.5, 1:2). The constant parameter is the stirring speed (300 rpm). Response Surface Methodology (RSM) in conjunction with the Central Composition Design (CCD) as employed to statistically evaluate and optimize the butanol extraction process. It was found that the distribution coefficient has achieved an optimum level of 1.92 % at the following conditions: (i) butanol-water mixtures to solvent ratio (1:1.48) and (ii) reaction temperature (62.75 degree Celsius). (author)

  5. Optimal recovery sequencing for critical infrastructure resilience assessment.

    Energy Technology Data Exchange (ETDEWEB)

    Vugrin, Eric D.; Brown, Nathanael J. K.; Turnquist, Mark Alan (Cornell University, Ithaca, NY)

    2010-09-01

    Critical infrastructure resilience has become a national priority for the U. S. Department of Homeland Security. System resilience has been studied for several decades in many different disciplines, but no standards or unifying methods exist for critical infrastructure resilience analysis. This report documents the results of a late-start Laboratory Directed Research and Development (LDRD) project that investigated the identification of optimal recovery strategies that maximize resilience. To this goal, we formulate a bi-level optimization problem for infrastructure network models. In the 'inner' problem, we solve for network flows, and we use the 'outer' problem to identify the optimal recovery modes and sequences. We draw from the literature of multi-mode project scheduling problems to create an effective solution strategy for the resilience optimization model. We demonstrate the application of this approach to a set of network models, including a national railroad model and a supply chain for Army munitions production.

  6. Optimal design of advanced distillation configuration for enhanced energy efficiency of waste solvent recovery process in semiconductor industry

    International Nuclear Information System (INIS)

    Chaniago, Yus Donald; Minh, Le Quang; Khan, Mohd Shariq; Koo, Kee-Kahb; Bahadori, Alireza; Lee, Moonyong

    2015-01-01

    Highlights: • Thermally coupled distillation process is proposed for waste solvent recovery. • A systematic optimization procedure is used to optimize distillation columns. • Response surface methodology is applied to optimal design of distillation column. • Proposed advanced distillation allows energy efficient waste solvent recovery. - Abstract: The semiconductor industry is one of the largest industries in the world. On the other hand, the huge amount of solvent used in the industry results in high production cost and potential environmental damage because most of the valuable chemicals discharged from the process are incinerated at high temperatures. A distillation process is used to recover waste solvent, reduce the production-related costs and protect the environment from the semiconductor industrial waste. Therefore, in this study, a distillation process was used to recover the valuable chemicals from semiconductor industry discharge, which otherwise would have been lost to the environment. The conventional sequence of distillation columns, which was optimized using the Box and sequential quadratic programming method for minimum energy objectives, was used. The energy demands of a distillation problem may have a substantial influence on the profitability of a process. A thermally coupled distillation and heat pump-assisted distillation sequence was implemented to further improve the distillation performance. Finally, a comparison was made between the conventional and advanced distillation sequences, and the optimal conditions for enhancing recovery were determined. The proposed advanced distillation configuration achieved a significant energy saving of 40.5% compared to the conventional column sequence

  7. Preload assessment and optimization in critically ill patients.

    Science.gov (United States)

    Voga, Gorazd

    2010-01-01

    Preload assessment and optimization is the basic hemodynamic intervention in critically ill. Beside clinical assessment, non-invasive or invasive assessment by measurement of various pressure or volume hemodynamic variables, are helpful for estimation of preload and fluid responsiveness. The use of dynamic variables is useful in particular subgroup of critically ill patients. In patients with inadequate preload, fluid responsiveness and inadequate flow, treatment with crystalloids or colloids is mandatory. When rapid hemodynamic response is necessary colloids are preferred.

  8. Reducing refinery CO2 emissions through amine solvent upgrade and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Thiago V.; Valenzuela, Michelle [The Dow Chemical Company, Midland, MI (United States)

    2012-07-01

    Regional initiatives are underway to reduce and limit the emissions of greenhouse gases. With CO2 emissions making up over 80% of the greenhouse gases, cap-and-trade programs will focus on those industries that consume the most energy. Refineries are among the top energy consumers and are seeking opportunities to reduce usage. With tightening margins, energy management programs will not only help refineries meet CO{sub 2} emission regulations, but can also provide a competitive advantage. With the trend towards heavier and higher sulfur containing crudes, refineries are increasing processing capabilities, which can include capital-intensive projects and additional energy consumption. Energy conservation plans should include optimization of these processes. One area to consider includes the acid gas removal systems in refineries. Through the selection and use of optimal solvents and implementation of energy efficiency techniques, which require minimal capital investment and expenditures, refineries can reduce energy usage, overall CO{sub 2} emissions, and total cost in acid gas systems. This paper will discuss these approaches and share case studies detailing the implementation and results. (author)

  9. Optimization of preparation conditions of polyamide thin film composite membrane for organic solvent nanofiltration

    International Nuclear Information System (INIS)

    Namvar-Mahboub, Mahdieh; Pakizeh, Majid

    2014-01-01

    Separation performance of polyamide composite membranes is affected by several parameters during formation of thin upper layer via interfacial polymerization. We investigated the effect of various polyamide synthesis conditions on the performance of organic solvent resistant polyamide composite membranes through the model equations designed by 2-level fractional factorial design. The dewaxing solvent recovery was selected as separation process. Five factors were changed in two level includin; TMC concentration (0.05-0.1%), MPD concentration (1-2%), support immersion time in organic solution (2-4 min), support immersion time in aqueous solution (1-2 min), and curing temperature (70-80 .deg. C). The resultant equations showed 93.48% and 94.82% of the variability (R 2 adj ) in data used to fit oil rejection and permeate flux models, respectively. The analysis of variance revealed that both models were high significant. It was also observed that TMC concentration, MPD concentration and immersion time in TMC have more pronounced effect on the oil rejection and permeate flux than other factors and interactions. Optimal polyamide preparation conditions were obtained using multiple response method for 94% oil rejection as target value. According to the results, the best value of permeate flux (8.86 l/(m 2 ·h)) was found at TMC concentration of 0.1%, MPD concentration of 1.94%, immersion time in TMC of 3.88 min, immersion time in MPD of 1.95 min and curing temperature of 71.96 .deg. C with desirability factor of 1

  10. Optimization of the solvent-based dissolution method to sample volatile organic compound vapors for compound-specific isotope analysis.

    Science.gov (United States)

    Bouchard, Daniel; Wanner, Philipp; Luo, Hong; McLoughlin, Patrick W; Henderson, James K; Pirkle, Robert J; Hunkeler, Daniel

    2017-10-20

    The methodology of the solvent-based dissolution method used to sample gas phase volatile organic compounds (VOC) for compound-specific isotope analysis (CSIA) was optimized to lower the method detection limits for TCE and benzene. The sampling methodology previously evaluated by [1] consists in pulling the air through a solvent to dissolve and accumulate the gaseous VOC. After the sampling process, the solvent can then be treated similarly as groundwater samples to perform routine CSIA by diluting an aliquot of the solvent into water to reach the required concentration of the targeted contaminant. Among solvents tested, tetraethylene glycol dimethyl ether (TGDE) showed the best aptitude for the method. TGDE has a great affinity with TCE and benzene, hence efficiently dissolving the compounds during their transition through the solvent. The method detection limit for TCE (5±1μg/m 3 ) and benzene (1.7±0.5μg/m 3 ) is lower when using TGDE compared to methanol, which was previously used (385μg/m 3 for TCE and 130μg/m 3 for benzene) [2]. The method detection limit refers to the minimal gas phase concentration in ambient air required to load sufficient VOC mass into TGDE to perform δ 13 C analysis. Due to a different analytical procedure, the method detection limit associated with δ 37 Cl analysis was found to be 156±6μg/m 3 for TCE. Furthermore, the experimental results validated the relationship between the gas phase TCE and the progressive accumulation of dissolved TCE in the solvent during the sampling process. Accordingly, based on the air-solvent partitioning coefficient, the sampling methodology (e.g. sampling rate, sampling duration, amount of solvent) and the final TCE concentration in the solvent, the concentration of TCE in the gas phase prevailing during the sampling event can be determined. Moreover, the possibility to analyse for TCE concentration in the solvent after sampling (or other targeted VOCs) allows the field deployment of the sampling

  11. Optimized Solvent for Energy-Efficient, Environmentally-Friendly Capture of CO{sub 2} at Coal-Fired Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Farthing, G. A.; Rimpf, L. M.

    2014-04-30

    The overall goal of this project, as originally proposed, was to optimize the formulation of a novel solvent as a critical enabler for the cost-effective, energy-efficient, environmentally-friendly capture of CO{sub 2} at coal-fired utility plants. Aqueous blends of concentrated piperazine (PZ) with other compounds had been shown to exhibit high rates of CO{sub 2} absorption, low regeneration energy, and other desirable performance characteristics during an earlier 5-year development program conducted by B&W. The specific objective of this project was to identify PZ-based solvent formulations that globally optimize the performance of coal-fired power plants equipped with CO{sub 2} scrubbing systems. While previous solvent development studies have tended to focus on energy consumption and absorber size, important issues to be sure, the current work seeks to explore, understand, and optimize solvent formulation across the full gamut of issues related to commercial application of the technology: capital and operating costs, operability, reliability, environmental, health and safety (EH&S), etc. Work on the project was intended to be performed under four budget periods. The objective of the work in the first budget period has been to identify several candidate formulations of a concentrated PZ-based solvent for detailed characterization and evaluation. Work in the second budget period would generate reliable and comprehensive property and performance data for the identified formulations. Work in the third budget period would quantify the expected performance of the selected formulations in a commercial CO{sub 2} scrubbing process. Finally, work in the fourth budget period would provide a final technology feasibility study and a preliminary technology EH&S assessment. Due to other business priorities, however, B&W has requested that this project be terminated at the end of the first budget period. This document therefore serves as the final report for this project. It

  12. Response Surface Optimization of Rotenone Using Natural Alcohol-Based Deep Eutectic Solvent as Additive in the Extraction Medium Cocktail

    Directory of Open Access Journals (Sweden)

    Zetty Shafiqa Othman

    2017-01-01

    Full Text Available Rotenone is a biopesticide with an amazing effect on aquatic life and insect pests. In Asia, it can be isolated from Derris species roots (Derris elliptica and Derris malaccensis. The previous study revealed the comparable efficiency of alcohol-based deep eutectic solvent (DES in extracting a high yield of rotenone (isoflavonoid to binary ionic liquid solvent system ([BMIM]OTf and organic solvent (acetone. Therefore, this study intends to analyze the optimum parameters (solvent ratio, extraction time, and agitation rate in extracting the highest yield of rotenone extract at a much lower cost and in a more environmental friendly method by using response surface methodology (RSM based on central composite rotatable design (CCRD. By using RSM, linear polynomial equations were obtained for predicting the concentration and yield of rotenone extracted. The verification experiment confirmed the validity of both of the predicted models. The results revealed that the optimum conditions for solvent ratio, extraction time, and agitation rate were 2 : 8 (DES : acetonitrile, 19.34 hours, and 199.32 rpm, respectively. At the optimum condition of the rotenone extraction process using DES binary solvent system, this resulted in a 3.5-fold increase in a rotenone concentration of 0.49 ± 0.07 mg/ml and yield of 0.35 ± 0.06 (%, w/w as compared to the control extract (acetonitrile only. In fact, the rotenone concentration and yield were significantly influenced by binary solvent ratio and extraction time (P<0.05 but not by means of agitation rate. For that reason, the optimal extraction condition using alcohol-based deep eutectic solvent (DES as a green additive in the extraction medium cocktail has increased the potential of enhancing the rotenone concentration and yield extracted.

  13. Optimization of partial multicanonical molecular dynamics simulations applied to an alanine dipeptide in explicit water solvent.

    Science.gov (United States)

    Okumura, Hisashi

    2011-01-07

    The partial multicanonical algorithm for molecular dynamics and Monte Carlo simulations samples a wide range of an important part of the potential energy. Although it is a strong technique for structure prediction of biomolecules, the choice of the partial potential energy has not been optimized. In order to find the best choice, partial multicanonical molecular dynamics simulations of an alanine dipeptide in explicit water solvent were performed with 15 trial choices for the partial potential energy. The best choice was found to be the sum of the electrostatic, Lennard-Jones, and torsion-angle potential energies between solute atoms. In this case, the partial multicanonical simulation sampled all of the local-minimum free-energy states of the P(II), C(5), α(R), α(P), α(L), and C states and visited these states most frequently. Furthermore, backbone dihedral angles ϕ and ψ rotated very well. It is also found that the most important term among these three terms is the electrostatic potential energy and that the Lennard-Jones term also helps the simulation to overcome the steric restrictions. On the other hand, multicanonical simulation sampled all of the six states, but visited these states fewer times. Conventional canonical simulation sampled only four of the six states: The P(II), C(5), α(R), and α(P) states.

  14. Choline chloride-based deep eutectic solvents as additives for optimizing chromatographic behavior of caffeic acid

    International Nuclear Information System (INIS)

    Li, Guizhen; Zhu, Tao; Lei, Yingjie

    2015-01-01

    A series of deep eutectic solvents (DESs) were prepared using glycerol and choline chloride (ChCl), and Fourier transform infrared spectrometer (FT-IR) was used to analyze the spectra of glycerol, choline chloride and DESs based on glycerol and choline chloride. Then DESs were used as the additives of mobile phase to optimize chromatographic behavior of caffeic acid in high performance liquid chromatography (HPLC). A 17-run Box-Behnken design (BBD) was employed to evaluate effect of DESs as additives by analyzing the maximum theoretical plate number. Three factors, reaction temperature (60 .deg. C, 80 .deg. C, 100 .deg. C), molar ratio of glycerol and choline chloride (2 : 1, 3 : 1, 4 : 1, n/n), and volume percent of additives (0.05%, 0.10%, 0.15%, v/v), were investigated in BBD. The optimum experiment condition was that of reaction temperature (80 .deg. C), molar ratio of glycerol and ChCl (3 : 1, n/n), and volume percent of additive (0.10%, v/v). The mean chromatographic theoretical plate number of the caffeic acid this condition was 1567.5, and DESs as additives shorten the retention time and modify the chromatogram shape, proving DESs as additives for effective theoretical plate number and column efficiency in HPLC.

  15. Choline chloride-based deep eutectic solvents as additives for optimizing chromatographic behavior of caffeic acid

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guizhen; Zhu, Tao; Lei, Yingjie [Tianjin University of Technology, Tianjin (China)

    2015-10-15

    A series of deep eutectic solvents (DESs) were prepared using glycerol and choline chloride (ChCl), and Fourier transform infrared spectrometer (FT-IR) was used to analyze the spectra of glycerol, choline chloride and DESs based on glycerol and choline chloride. Then DESs were used as the additives of mobile phase to optimize chromatographic behavior of caffeic acid in high performance liquid chromatography (HPLC). A 17-run Box-Behnken design (BBD) was employed to evaluate effect of DESs as additives by analyzing the maximum theoretical plate number. Three factors, reaction temperature (60 .deg. C, 80 .deg. C, 100 .deg. C), molar ratio of glycerol and choline chloride (2 : 1, 3 : 1, 4 : 1, n/n), and volume percent of additives (0.05%, 0.10%, 0.15%, v/v), were investigated in BBD. The optimum experiment condition was that of reaction temperature (80 .deg. C), molar ratio of glycerol and ChCl (3 : 1, n/n), and volume percent of additive (0.10%, v/v). The mean chromatographic theoretical plate number of the caffeic acid this condition was 1567.5, and DESs as additives shorten the retention time and modify the chromatogram shape, proving DESs as additives for effective theoretical plate number and column efficiency in HPLC.

  16. Solvent extraction

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, D.M.; Latimer, E.G.

    1988-01-05

    It is an object of this invention to provide for the demetallization and general upgrading of heavy oil via a solvent extracton process, and to improve the efficiency of solvent extraction operations. The yield and demetallization of product oil form heavy high-metal content oil is maximized by solvent extractions which employ either or all of the following techniques: premixing of a minor amount of the solvent with feed and using countercurrent flow for the remaining solvent; use of certain solvent/free ratios; use of segmental baffle tray extraction column internals and the proper extraction column residence time. The solvent premix/countercurrent flow feature of the invention substantially improves extractions where temperatures and pressures above the critical point of the solvent are used. By using this technique, a greater yield of extract oil can be obtained at the same metals content or a lower metals-containing extract oil product can be obtained at the same yield. Furthermore, the premixing of part of the solvent with the feed before countercurrent extraction gives high extract oil yields and high quality demetallization. The solvent/feed ratio features of the invention substanially lower the captial and operating costs for such processes while not suffering a loss in selectivity for metals rejection. The column internals and rsidence time features of the invention further improve the extractor metals rejection at a constant yield or allow for an increase in extract oil yield at a constant extract oil metals content. 13 figs., 3 tabs.

  17. Increasing the sampling efficiency of protein conformational transition using velocity-scaling optimized hybrid explicit/implicit solvent REMD simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yuqi; Wang, Jinan; Shao, Qiang, E-mail: qshao@mail.shcnc.ac.cn, E-mail: Jiye.Shi@ucb.com, E-mail: wlzhu@mail.shcnc.ac.cn; Zhu, Weiliang, E-mail: qshao@mail.shcnc.ac.cn, E-mail: Jiye.Shi@ucb.com, E-mail: wlzhu@mail.shcnc.ac.cn [ACS Key Laboratory of Receptor Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203 (China); Shi, Jiye, E-mail: qshao@mail.shcnc.ac.cn, E-mail: Jiye.Shi@ucb.com, E-mail: wlzhu@mail.shcnc.ac.cn [UCB Pharma, 216 Bath Road, Slough SL1 4EN (United Kingdom)

    2015-03-28

    The application of temperature replica exchange molecular dynamics (REMD) simulation on protein motion is limited by its huge requirement of computational resource, particularly when explicit solvent model is implemented. In the previous study, we developed a velocity-scaling optimized hybrid explicit/implicit solvent REMD method with the hope to reduce the temperature (replica) number on the premise of maintaining high sampling efficiency. In this study, we utilized this method to characterize and energetically identify the conformational transition pathway of a protein model, the N-terminal domain of calmodulin. In comparison to the standard explicit solvent REMD simulation, the hybrid REMD is much less computationally expensive but, meanwhile, gives accurate evaluation of the structural and thermodynamic properties of the conformational transition which are in well agreement with the standard REMD simulation. Therefore, the hybrid REMD could highly increase the computational efficiency and thus expand the application of REMD simulation to larger-size protein systems.

  18. Solvent Composition is Critical for Carbodiimide Cross-Linking of Hyaluronic Acid as an Ophthalmic Biomaterial

    Directory of Open Access Journals (Sweden)

    Jui-Yang Lai

    2012-10-01

    Full Text Available Hyaluronic acid (HA is one of the most important ophthalmic biomaterials, while also being used for tissue engineering and drug delivery. Although chemical cross-linking is an effective way to improve the material performance, it may as a consequence be detrimental to the living cells/tissues. Given that the cross-linking efficiency is mediated by the solvent composition during the chemical modification, this study aims to explore the stability and biocompatibility of carbodiimide cross-linked HA in relation to material processing conditions by varying the acetone/water volume ratio (from 70:30 to 95:5 at a constant 1-ethyl-3-(3-dimethyl aminopropyl carbodiimide (EDC concentration of 100 mM. Our results indicated that after the EDC treatment in the presence of an acetone/water mixture (85:15, v/v, the HA hydrogel membranes have the lowest equilibrium water content, the highest stress at break and the greatest resistance to hyaluronidase digestion. Live/Dead assays and pro-inflammatory cytokine expression analyses showed that the cross-linked HA hydrogel membranes, irrespective of the solvent composition, are compatible with human RPE cell lines without causing toxicity and inflammation. However, it should be noted that the test samples prepared by the cross-linking in the presence of acetone/water mixtures containing 70, 75, and 95 vol % of acetone slightly inhibit the metabolic activity of viable ARPE-19 cultures, probably due to the alteration in the ionic interaction between the medium nutrients and polysaccharide biomaterials. In summary, the water content, mechanical strength and RPE cell proliferative capacity strongly depends on the solvent composition for carbodiimide cross-linking of HA materials.

  19. Multiple responses optimization in the development of a headspace gas chromatography method for the determination of residual solvents in pharmaceuticals

    Directory of Open Access Journals (Sweden)

    Carla M. Teglia

    2015-10-01

    Full Text Available An efficient generic static headspace gas chromatography (HSGC method was developed, optimized and validated for the routine determination of several residual solvents (RS in drug substance, using a strategy with two sets of calibration. Dimethylsulfoxide (DMSO was selected as the sample diluent and internal standards were used to minimize signal variations due to the preparative step. A gas chromatograph from Agilent Model 6890 equipped with flame ionization detector (FID and a DB-624 (30 m×0.53 mm i.d., 3.00 µm film thickness column was used. The inlet split ratio was 5:1. The influencing factors in the chromatographic separation of the analytes were determined through a fractional factorial experimental design. Significant variables: the initial temperature (IT, the final temperature (FT of the oven and the carrier gas flow rate (F were optimized using a central composite design. Response transformation and desirability function were applied to find out the optimal combination of the chromatographic variables to achieve an adequate resolution of the analytes and short analysis time. These conditions were 30 °C for IT, 158 °C for FT and 1.90 mL/min for F. The method was proven to be accurate, linear in a wide range and very sensitive for the analyzed solvents through a comprehensive validation according to the ICH guidelines. Keywords: Headspace gas chromatography, Residual solvents, Pharmaceuticals, Surface response methodology, Desirability function

  20. Optimization of direct solvent lipid extraction kinetics on marine trebouxiophycean alga by central composite design – Bioenergy perspective

    International Nuclear Information System (INIS)

    Mathimani, Thangavel; Uma, Lakshmanan; Prabaharan, Dharmar

    2017-01-01

    Highlights: • Direct solvent extraction is an appropriate pretreatment for marine C. vulgaris. • 2:1 chloroform/methanol, 1:5 DCW/solvent, 65 °C and 120 min time are optimal variables. • Favorable R"2, Prob > F, F value and desirability ratio for all models was observed. • Precision and compatibility of the optimized process suit well with Picochlorum sp. • Fuel properties of biodiesel comply ASTM, EN and ISO standards. - Abstract: This present work compares various pretreatment techniques, single/binary solvent system, biomass drying methods and biomass particle sizes to ascertain effective lipid extraction process for marine trebouxiophycean microalga Chlorella vulgaris BDUG 91771. Of the tested methods, homogenization or direct solvent extraction (DSE) pretreatment, chloroform/methanol binary solvent system, and ≤600 µm particle size extracted maximum lipid of 22.1% irrespective of different biomass drying methods. Further, considering low energy consumption and industrial feasibility, optimization of DSE process kinetics was performed by central composite design. According to central composite design, high lipid recovery was attained with 2:1 chloroform/methanol ratio, 1:5 dry cell weight/solvent ratio, 65 °C temperature, 120 min reaction time, and it was highly validated by regression analysis, coefficient determination, F-value, coefficient variation, desirability ratio of the models. It is noteworthy that, the optimized DSE process was compatible with another trebouxiophycean alga Picochlorum sp. BDUG 91281 through biological and technical replicates. In a bioenergy outlook, fuel properties of C. vulgaris BDUG 91771 biodiesel such as degree of unsaturation (69.03), long chain saturation factor (2.49), cold filter plugging point (−9.75 °C), cloud point (8.1 °C), pour point (0.66 °C), saponification value (248.2 mg KOH/g), acid value (0.51 mg KOH/g), ash content (0.019%), insoluble impurities (0.022 g/kg) and viscosity (4.1 cSt) comply ASTM

  1. Cost-Optimal Analysis for Nearly Zero Energy Buildings Design and Optimization: A Critical Review

    Directory of Open Access Journals (Sweden)

    Maria Ferrara

    2018-06-01

    Full Text Available Since the introduction of the recast of the EPBD European Directive 2010/31/EU, many studies on the cost-effective feasibility of nearly zero-energy buildings (NZEBs were carried out either by academic research bodies and by national bodies. In particular, the introduction of the cost-optimal methodology has given a strong impulse to research in this field. This paper presents a comprehensive and significant review on scientific works based on the application of cost-optimal analysis applications in Europe since the EPBD recast entered into force, pointing out the differences in the analyzed studies and comparing their outcomes before the new recast of EPBD enters into force in 2018. The analysis is conducted with special regard to the methods used for the energy performance assessment, the global cost calculation, and for the selection of the energy efficiency measures leading to design optimization. A critical discussion about the assumptions on which the studies are based and the resulting gaps between the resulting cost-optimal performance and the zero energy target is provided together with a summary of the resulting cost-optimal set of technologies to be used for cost-optimal NZEB design in different contexts. It is shown that the cost-optimal approach results as an effective method for delineating the future of NZEB design throughout Europe while emerging criticalities and open research issues are presented.

  2. Optimal use of atherectomy in critical limb ischemia.

    Science.gov (United States)

    Rundback, John H; Herman, Kevin Chaim

    2014-09-01

    Critical limb ischemia (CLI) is the most severe and debilitating form of peripheral arterial disease and is associated with high rates of limb loss and cardiovascular mortality. The unique physical environment of tibial occlusive disease underlying most CLI cases limits treatment options and long-term durability, with resulting frequent rates of persistent obstruction, restenosis, and reintervention. Atherectomy represents a potential strategy to improve acute and late results when treating patients with CLI. Available atherectomy devices each have specific performance characteristics, evidentiary rationale, and limitations that mandate a clear understanding of the optimal albeit evolving use of this category of interventional tools. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Resin purification from Dragons Blood by using sub critical solvent extraction method

    Science.gov (United States)

    Saifuddin; Nahar

    2018-04-01

    Jernang resin (dragon blood) is the world's most expensive sap. The resin obtained from jernang that grows only on the islands of Sumatra and Borneo. Jernang resin is in demand by the State of China, Hong Kong, and Singapore since they contain compounds that have the potential dracohordin as a medicinal ingredient in the biological and pharmacological activity such as antimicrobial, antiviral, antitumor and cytotoxic activity. The resin extracting process has conventionally been done by drizzly with maceration method as one way of processing jernang, which is done by people in Bireuen, Aceh. However, there are still significant obstacles, namely the quality of the yield that obtained lower than the jernang resin. The technological innovation carried out by forceful extraction process maceration by using methanol produced a yield that is higher than the extraction process maceration method carried out in Bireuen. Nevertheless, the use of methanol as a solvent would raise the production costs due to the price, which is relatively more expensive and non-environmentally friendly. To overcome the problem, this research proposed a process, which is known as subcritical solvent method. This process is cheap, and also abundant and environmentally friendly. The results show that the quality of jernang resins is better than the one that obtained by the processing group in Bireuen. The quality of the obtained jernang by maceration method is a class-A quality based on the quality specification requirements of jernang (SNI 1671: 2010) that has resin (b/b) 73%, water (w/w) of 6.8%, ash (w/b) 7%, impurity (w/w) 32%, the melting point of 88°C and red colours. While the two-stage treatment obtained a class between class-A and super quality, with the resin (b/b) 0.86%, water (w/w) of 6.5%, ash (w/w) of 2.8%, levels of impurities (w/w) of 9%, the melting point of 88 °C and dark-red colours.

  4. Application of 2k Full Factorial Design in Optimization of Solvent-Free Microwave Extraction of Ginger Essential Oil

    Directory of Open Access Journals (Sweden)

    Mumtaj Shah

    2014-01-01

    Full Text Available The solvent-free microwave extraction of essential oil from ginger was optimized using a 23 full factorial design in terms of oil yield to determine the optimum extraction conditions. Sixteen experiments were carried out with three varying parameters, extraction time, microwave power, and type of sample for two levels of each. A first order regression equation best fits the experimental data. The predicted values calculated by the regression model were in good agreement with the experimental values. The results showed that the extraction time is the most prominent factor followed by microwave power level and sample type for extraction process. An average of 0.25% of ginger oil can be extracted using current setup. The optimum conditions for the ginger oil extraction using SFME were the extraction time 30 minutes, microwave power level 640 watts, and sample type, crushed sample. Solvent-free microwave extraction proves a green and promising technique for essential oil extraction.

  5. Economic risk analysis and critical comparison of optimal biorefinery concepts

    DEFF Research Database (Denmark)

    Cheali, Peam; Posada, John A.; Gernaey, Krist

    2016-01-01

    In this paper, eight optimal biorefinery concepts for biofuels and biochemicals production are critically analyzed and compared in terms of their techno-economic performance and associated economic risks against historical market fluctuations. The investigated biorefinery concepts consider...... different combinations of biomass feedstock (lignocellulosic versus algal) and conversion technologies (biochemical versus thermochemical). In addition, the economic performance of each biorefinery concept is tested assuming a sudden drop in oil prices in order to compare the fitness/survival of each...... concept under extreme market disturbances. The analyses reveal amongst others that: (i) lignocellulosic bioethanol production is not economically feasible considering a drop in oil prices (a negative internal rate of return); (ii) a multi-product biorefinery concept, where bioethanol is upgraded to higher...

  6. Systemic study of solvent-assisted active loading of gambogic acid into liposomes and its formulation optimization for improved delivery.

    Science.gov (United States)

    Tang, Wei-Lun; Tang, Wei-Hsin; Szeitz, Andras; Kulkarni, Jayesh; Cullis, Pieter; Li, Shyh-Dar

    2018-06-01

    The solvent-assisted active loading technology (SALT) was developed for encapsulating a water insoluble weak base into the liposomal core in the presence of 5% DMSO. In this study, we further examined the effect of various water miscible solvents in promoting active loading of other types of drugs into liposomes. To achieve complete drug loading, the amount of solvent required must result in complete drug solubilization and membrane permeability enhancement, but must be below the threshold that induces liposomal aggregation or causes bilayer disruption. We then used the SALT to load gambogic acid (GA, an insoluble model drug that shows promising anticancer effect) into liposomes, and optimized the loading gradient and lipid composition to prepare a stable formulation (Lipo-GA) that displayed >95% drug retention after incubation with serum for 3 days. Lipo-GA contained a high drug-to-lipid ratio of 1/5 (w/w) with a mean particle size of ∼75 nm. It also displayed a prolonged circulation half-life (1.5 h vs. 18.6 h) and enhanced antitumor activity in two syngeneic mice models compared to free GA. Particularly, complete tumor regression was observed in the EMT6 tumor model for 14 d with significant inhibition of multiple oncogenes including HIF-1α, VEGF-A, STAT3, BCL-2, and NF-κB. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Solvent optimization extraction of antioxidants from foxtail millet species' insoluble fibers and their free radical scavenging properties.

    Science.gov (United States)

    Bangoura, Mohamed Lamine; Nsor-Atindana, John; Ming, Zhou Hui

    2013-11-15

    In this study, water and 80% of four organic solvents were employed to optimize the extraction of antioxidants from two species of foxtail millet's insoluble fibers under the same temperature, time, and solid/solvent ratio. The results showed that the acetone was able to extract the maximum amount of antioxidants (2.32 mg/g fiber for white specie and 3.86 mg/g fiber for yellow specie) followed by methanol and propanol from both samples. The neutral and the ethanol on the other hand extracted small amount of the antioxidants from the two fiber materials. While considerable level of Total Polyphenols Content (TPC) was recorded in both the water and the organic solvents' extracts, only traces of Total Flavonoid content (TFC) were observed in water, methanol and ethanol extracts. Propanol and acetone extracts was negative to the TFC test. The potency of both white and yellow foxtail millets' insoluble fibers antioxidant extracts was investigated using five different in vitro tests. It was realized that there was a variation in their capacities to quench DPPH and ABTS(+) radicals for the time running of 0-60 min. The samples from the yellow cereal exhibited high inhibition capacity against ABTS(+). No correlation was observed between TPC and radical scavenging capacities for DPPH and ABTS(+). In general, the yellow species contained more antioxidants in comparison with the white one and this accounted for its high antioxidant activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Optimization of methotrexate loaded niosomes by Box-Behnken design: an understanding of solvent effect and formulation variability.

    Science.gov (United States)

    Zidan, Ahmed S; Mokhtar Ibrahim, Mahmoud; Megrab, Nagia A El

    2017-09-01

    Dermal drug delivery system which localizes methotrexate (MTX) in the skin is advantageous in topical treatment of psoriasis. The aim of the current study was to understand dilution effects and formulation variability for the potential formation of niosomes from proniosome gels of MTX. Box-Behnken's design was employed to prepare a series of MTX proniosome gels of Span 40, cholesterol (Chol-X 1 ) and Tween 20 (T20-X 2 ). Short chain alcohols (X 3 ), namely ethanol (Et), propylene glycol (Pg) and glycerol (G) were evaluated for their dilution effects on proniosomes. The responses investigated were niosomal vesicles size (Y 1 ), MTX entrapment efficiency percent (EE%-Y 2 ) and zeta potential (Y 3 ). MTX loaded niosomes were formed immediately upon hydration of the proniosome gels with the employed solvents. Addition of Pg resulted in a decrease of vesicular size from 534 nm to 420 nm as Chol percentage increased from 10% to 30%, respectively. In addition, increasing the hydrophilicity of the employed solvents was enhancing the resultant zeta potential. On the other hand, using Et in proniosomal gels would abolish Chol action to increase the zeta potential value and hence less stable niosomal dispersion was formed. The optimized formula of MTX loaded niosomes showed vesicle size of 480 nm, high EE% (55%) and zeta potential of -25.5 mV, at Chol and T20 concentrations of 30% and 23.6%, respectively, when G was employed as the solvent. Hence, G was the solvent of choice to prepare MTX proniosomal gels with a maintained stability and highest entrapment.

  9. Rheological profiling of organogels prepared at critical gelling concentrations of natural waxes in a triacylglycerol solvent.

    Science.gov (United States)

    Patel, Ashok R; Babaahmadi, Mehrnoosh; Lesaffer, Ans; Dewettinck, Koen

    2015-05-20

    The aim of this study was to use a detailed rheological characterization to gain new insights into the gelation behavior of natural waxes. To make a comprehensive case, six natural waxes (differing in the relative proportion of chemical components: hydrocarbons, fatty alcohols, fatty acids, and wax esters) were selected as organogelators to gel high-oleic sunflower oil. Flow and dynamic rheological properties of organogels prepared at critical gelling concentrations (Cg) of waxes were studied and compared using drag (stress ramp and steady flow) and oscillatory shear (stress and frequency sweeps) tests. Although, none of the organogels satisfied the rheological definition of a "strong gel" (G″/G' (ω) ≤ 0.1), on comparing the samples, the strongest gel (highest critical stress and dynamic, apparent, and static yield stresses) was obtained not with wax containing the highest proportion of wax esters alone (sunflower wax, SFW) but with wax containing wax esters along with a higher proportion of fatty alcohols (carnauba wax, CRW) although at a comparatively higher Cg (4%wt for latter compared to 0.5%wt for former). As expected, gel formation by waxes containing a high proportion of lower melting fatty acids (berry, BW, and fruit wax, FW) required a comparatively higher Cg (6 and 7%wt, respectively), and in addition, these gels showed the lowest values for plateau elastic modulus (G'LVR) and a prominent crossover point at higher frequency. The gelation temperatures (TG'=G″) for all the studied gels were lower than room temperature, except for SFW and CRW. The yielding-type behavior of gels was evident, with most gels showing strong shear sensitivity and a weak thixotropic recovery. The rheological behavior was combined with the results of thermal analysis and microstructure studies (optical, polarized, and cryo-scanning electron microscopy) to explain the gelation properties of these waxes.

  10. Solvent optimization on Taxol extraction from Taxus baccata L., using HPLC and LC-MS

    Directory of Open Access Journals (Sweden)

    H Sadeghi-aliabadi

    2009-10-01

    Full Text Available "nBackground and the purpose of the study: Taxol, a natural antitumor agent, was first isolated from the extract of the bark of Taxus brevifolia Nutt., which is potentially a limited source for Taxol. In the search of an alternative source, optimum and cost benefit extracting solvents, various solvents with different percentage were utilized to extract Taxol from needles of Taxus baccata. "nMethods: One g of the dried needles of Taxus baccata, collected from Torkaman and Noor cities of Iran, was extracted with pure ethanol or acetone and 50% and 20% of ethanol or acetone in water. Solvents were evaporated to dryness and the residues were dissolved in 5 ml of methanol and filtered. To one ml of the filtrate was added 50 μl of cinamyl acetate as the internal standard and 20 μl of the resulting solution was subjected to the HPLC to determine the extraction efficiencies of tested solvents. Five μl of filtrate was also subjected to the LC-MS using water/acetonitrile (10/90 as mobile phase and applying positive electrospray ionization (ESI to identify the authenticity of Taxol. "nResults: Results of this study indicated that Taxol extraction efficiency was enhanced as the percentage of ethanol or acetone was increased. HPLC analysis showed that Taxol could be quantified by UV detection using standard curve. The standard curve covering the concentration ranges of 7.8 - 500 μg/ml was linear (r2= 0.9992 and CV% ranged from 0.52 to 15.36. LC-MS analysis using ESI in positive-ion mode confirmed the authenticity of Taxol (m/z 854; M+H, as well as some adduct ions such as M+Na (m/z 876, M+K (m/z 892 and M+CH3CN+H2O (m/z 913. "nConclusions: The results suggest that 100% acetone is the best solvent for the extraction of Taxol from Taxus baccata needles.

  11. Optimization of co-solvent addition in supercritical fluid extraction of fat with carbon dioxide

    Directory of Open Access Journals (Sweden)

    Ivanov Dušica S.

    2011-01-01

    Full Text Available This investigation is concerned with supercritical fluid extraction (SFE using CO2, as an analytical technique for total fat extraction from food and feed samples. Its most significant advantages are safety, cleanness, and shorter extraction time. The main limitation of this technique includes the difficulty of extracting polar lipids due to the non-polar character of the solvent (CO2 used for the extraction. The influence of ethanol as a co-solvent on the SFE of mash pig feed was investigated in this paper. Total fat content was determined by SFE and Soxhlet method for ten commercially available mesh pig feeds. Yields of the fat extracted by both methods were plotted one against the other and compared. Statistically significant difference (p ≤ 0.05 has been found only between the total fat obtained by the Soxhlet extraction and SFE by pure CO2. Based on the mathematical model, maximum yield of the extracted fat is achieved at an ethanol addition of 0.67 ml/g of sample, when the other parameters are the same as recommended by the producer’s procedure.

  12. Optimal ROS Signaling Is Critical for Nuclear Reprogramming

    Directory of Open Access Journals (Sweden)

    Gang Zhou

    2016-05-01

    Full Text Available Efficient nuclear reprogramming of somatic cells to pluripotency requires activation of innate immunity. Because innate immune activation triggers reactive oxygen species (ROS signaling, we sought to determine whether there was a role of ROS signaling in nuclear reprogramming. We examined ROS production during the reprogramming of doxycycline (dox-inducible mouse embryonic fibroblasts (MEFs carrying the Yamanaka factors (Oct4, Sox2, Klf4, and c-Myc [OSKM] into induced pluripotent stem cells (iPSCs. ROS generation was substantially increased with the onset of reprogramming. Depletion of ROS via antioxidants or Nox inhibitors substantially decreased reprogramming efficiency. Similarly, both knockdown and knockout of p22phox—a critical subunit of the Nox (1–4 complex—decreased reprogramming efficiency. However, excessive ROS generation using genetic and pharmacological approaches also impaired reprogramming. Overall, our data indicate that ROS signaling is activated early with nuclear reprogramming, and optimal levels of ROS signaling are essential to induce pluripotency.

  13. Process optimization for production and purification of a thermostable, organic solvent tolerant lipase from Acinetobacter sp. AU07

    Directory of Open Access Journals (Sweden)

    P. Gururaj

    Full Text Available ABSTRACT The purpose of this study was to isolate, purify and optimize the production conditions of an organic solvent tolerant and thermostable lipase from Acinetobacter sp. AU07 isolated from distillery waste. The lipase production was optimized by response surface methodology, and a maximum production of 14.5 U/mL was observed at 30 ºC and pH 7, using a 0.5% (v/v inoculum, 2% (v/v castor oil (inducer, and agitation 150 rpm. The optimized conditions from the shake flask experiments were validated in a 3 L lab scale bioreactor, and the lipase production increased to 48 U/mL. The enzyme was purified by ammonium sulfate precipitation and ion exchange chromatography and the overall yield was 36%. SDS-PAGE indicated a molecular weight of 45 kDa for the purified protein, and Matrix assisted laser desorption/ionization time of flight analysis of the purified lipase showed sequence similarity with GDSL family of lipases. The optimum temperature and pH for activity of the enzyme was found to be 50 ºC and 8.0, respectively. The lipase was completely inhibited by phenylmethylsulfonyl fluoride but minimal inhibition was observed when incubated with ethylenediaminetetraacetic acid and dithiothreitol. The enzyme was stable in the presence of non-polar hydrophobic solvents. Detergents like SDS inhibited enzyme activity; however, there was minimal loss of enzyme activity when incubated with hydrogen peroxide, Tween 80 and Triton X-100. The kinetic constants (Km and Vmax revealed that the hydrolytic activity of the lipase was specific to moderate chain fatty acid esters. The Vmax, Km and Vmax/Km ratio of the enzyme were 16.98 U/mg, 0.51 mM, and 33.29, respectively when 4-nitrophenyl palmitate was used as a substrate.

  14. Production, Optimization, and Characterization of Organic Solvent Tolerant Cellulases from a Lignocellulosic Waste-Degrading Actinobacterium, Promicromonospora sp. VP111.

    Science.gov (United States)

    Thomas, Lebin; Ram, Hari; Kumar, Alok; Singh, Ved Pal

    2016-07-01

    High costs of natural cellulose utilization and cellulase production are an industrial challenge. In view of this, an isolated soil actinobacterium identified as Promicromonospora sp. VP111 showed potential for production of major cellulases (CMCase, FPase, and β-glucosidase) utilizing untreated agricultural lignocellulosic wastes. Extensive disintegration of microcrystalline cellulose and adherence on it during fermentation divulged true cellulolytic efficiency of the strain. Conventional optimization resulted in increased cellulase yield in a cost-effective medium, and the central composite design (CCD) analysis revealed cellulase production to be limited by cellulose and ammonium sulfate. Cellulase activities were enhanced by Co(+2) (1 mM) and retained up to 60 °C and pH 9.0, indicating thermo-alkaline tolerance. Cellulases showed stability in organic solvents (25 % v/v) with log P ow  ≥ 1.24. Untreated wheat straw during submerged fermentation was particularly degraded and yielded about twofold higher levels of cellulases than with commercial cellulose (Na-CMC and avicel) which is especially economical. Thus, this is the first detailed report on cellulases from an efficient strain of Promicromonospora that was non-hemolytic, alkali-halotolerant, antibiotic (erythromycin, kanamycin, rifampicin, cefaclor, ceftazidime) resistant, multiple heavy metal (Mo(+6) = W(+6) > Pb(+2) > Mn(+2) > Cr(+3) > Sn(+2)), and organic solvent (n-hexane, isooctane) tolerant, which is industrially and environmentally valuable.

  15. Methods optimization for the first time core critical

    International Nuclear Information System (INIS)

    Yan Liang

    2014-01-01

    The PWR reactor core commissioning programs the content of the first critical reactor physics experiment, and describes thc physical test method. However, all the methods arc not exactly the same but efficient. This article aims to enhance the reactor for the first time in the process of critical safety, shorten the overall time of critical physical test for the first time, and improve the integrity of critical physical test data for the first time and accuracy, eventually to improve the operation of the plant economic benefit adopting sectional dilution, power feedback for Doppler point improvement of physical test methods, and so on. (author)

  16. Optimization of 2-ethylhexyl palmitate production using lipozyme RM IM as catalyst in a solvent-free system.

    Science.gov (United States)

    Richetti, Aline; Leite, Selma G F; Antunes, Octávio A C; de Souza, Andrea L F; Lerin, Lindomar A; Dallago, Rogério M; Paroul, Natalia; Di Luccio, Marco; Oliveira, J Vladimir; Treichel, Helen; de Oliveira, Débora

    2010-04-01

    This work reports the application of a lipase in the 2-ethylhexyl palmitate esterification in a solvent-free system with an immobilized lipase (Lipozyme RM IM). A sequential strategy was used applying two experimental designs to optimize the 2-ethylhexyl palmitate production. An empirical model was then built so as to assess the effects of process variables on the reaction conversion. Afterwards, the operating conditions that optimized 2-ethylhexyl palmitate production were established as being acid/alcohol molar ratio 1:3, temperature of 70 degrees C, stirring rate of 150 rpm, 10 wt.% of enzyme, leading to a reaction conversion as high as 95%. From this point, a kinetic study was carried out evaluating the effect of acid:alcohol molar ratio, the enzyme concentration and the temperature on product conversion. The results obtained in this step permit to verify that an excess of alcohol (acid to alcohol molar ratio of 1:6), relatively low enzyme concentration (10 wt.%) and temperature of 70 degrees C, led to conversions next to 100%.

  17. Optimization process condition for deacidification of palm oil by liquid-liquid extraction using NADES (Natural Deep Eutectic Solvent)

    Science.gov (United States)

    Israyandi, Zahrina, Ida; Mulia, Kamarza

    2017-03-01

    One of many steps in palm oil refining process is deacidification which aims to separate free fatty acids and other compounds from the oil. The deacidification process was using a green solvent, known as NADES, that consisted of betaine monohydrate and propionic acid at molar ratio of 1:8. In this study, the process conditions were optimized using the response surface method (RSM) through central composite design in order to predict the maximum distribution coefficient of palmitic acid. The obtained regression equation of the basic model for optimization was: y = 0.717 + 0.003x1 + 0.043 x2 + 0.148x3 - 0.005 x1x1 - 0.030 x2x2 + 0.047 x3x3 - 0.008 x1x2 + 0.008 x1x3 + 0.033 x2x3. The independent variables are x1 ≡ temperature (40, 60, 80 °C), x2≡ amount of palmitic acid in the palm oil (2, 5, 8 %) and x3 ≡ mass ratios of oil to NADES (1:2, 1:1, 2:1). The optimum process condition found was temperature of 62.3°C, palmitic acid content of 8%, and NADES to palm oil mass ratio of 1:2, resulting in the maximum distribution coefficient of 0.96.

  18. Optimization and application of homogeneous liquid-liquid extraction in preconcentration of copper (II) in a ternary solvent system

    Energy Technology Data Exchange (ETDEWEB)

    Farajzadeh, Mir Ali [Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)], E-mail: farajzade@yahoo.com; Bahram, Morteza [Department of Chemistry, Faculty of Science, Urmia University, Urmia (Iran, Islamic Republic of); Zorita, Saioa [Department of Analytical Chemistry, University of Lund, P.O. Box 124, 221 00 Lund (Sweden); Mehr, Behzad Ghorbani [Department of Chemistry, Faculty of Science, Urmia University, Urmia (Iran, Islamic Republic of)

    2009-01-30

    In this study a homogeneous liquid-liquid extraction based on the Ph-dependent phase-separation process was investigated using a ternary solvent system (water-acetic acid-chloroform) for the preconcentration of Cu{sup 2+} ions. 8-Hydroxy quinoline was used as the chelating agent prior to its extraction. Flame atomic absorption spectrophotometry using acetylene-air flame was used for the quantitation of analyte after preconcentration. The effect of various experimental parameters in extraction step was investigated using two optimization methods, one variable at a time and central composite design. The experimental design was done at five levels of operating parameters. Nearly the same optimized results were obtained using both methods: sample size, 5 mL; volume of NaOH 10 M, 2 mL; chloroform volume, 300 {mu}L; 8-hydroxy quinoline concentration more than 0.01 M and salt amount did not affect the extraction significantly. Under the optimum conditions the calibration graph was linear over the range 10-2000 {mu}g L{sup -1}. The relative standard deviation was 7.6% for six repeated determinations (C = 500 {mu}g L{sup -1}). Furthermore, the limit of detection (S/N = 3) and limit of quantification (S/N = 10) of the method were obtained as 1.74 and 6 {mu}g L{sup -1}, respectively.

  19. Critical solvent properties affecting the particle formation process and characteristics of celecoxib-loaded plga microparticles via spray-drying.

    Science.gov (United States)

    Wan, Feng; Bohr, Adam; Maltesen, Morten Jonas; Bjerregaard, Simon; Foged, Camilla; Rantanen, Jukka; Yang, Mingshi

    2013-04-01

    It is imperative to understand the particle formation mechanisms when designing advanced nano/microparticulate drug delivery systems. We investigated how the solvent power and volatility influence the texture and surface chemistry of celecoxib-loaded poly (lactic-co-glycolic acid) (PLGA) microparticles prepared by spray-drying. Binary mixtures of acetone and methanol at different molar ratios were applied to dissolve celecoxib and PLGA prior to spray-drying. The resulting microparticles were characterized with respect to morphology, texture, surface chemistry, solid state properties and drug release profile. The evaporation profiles of the feed solutions were investigated using thermogravimetric analysis (TGA). Spherical PLGA microparticles were obtained, irrespectively of the solvent composition. The particle size and surface chemistry were highly dependent on the solvent power of the feed solution. An obvious burst release was observed for the microparticles prepared by the feed solutions with the highest amount of poor solvent for PLGA. TGA analysis revealed distinct drying kinetics for the binary mixtures. The particle formation process is mainly governed by the PLGA precipitation rate, which is solvent-dependent, and the migration rate of celecoxib molecules during drying. The texture and surface chemistry of the spray-dried PLGA microparticles can therefore be tailored by adjusting the solvent composition.

  20. Optimization of critical medium components for higher phycocyanin ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-09-01

    Sep 1, 2009 ... culture medium was screened and optimized using the statistical experimental designs of Plackett- .... statistical inference for exploring the functional relation- ..... from the F-test with a very low probability value (0.0015).

  1. Optimization of the process loop for CO{sub 2} capture by solvents

    Energy Technology Data Exchange (ETDEWEB)

    Burkhardt, Thorsten; Camy-Portenabe, Julien; Fradet, Aude; Tobiesen, Andrew; Svendsen, Hallvard F [Institut Francais du Petrole, Vernaison (France)

    2006-07-01

    A plant for the CO{sub 2} capture of a coal fired power plant is simulated by three commercial simulation tools (i.e. Aspen Plus, Hysys and Protreat). The results are generally in reasonable agreement. However, the CO{sub 2} removal is significantly higher in the Aspen Plus simulation, most probably due to the used 'Radfrac' column model which does not account for the mass transfer resistance and the chemical kinetics, thus overestimating the CO{sub 2} absorption. An optimization is carried out with respect to lean loading level and circulation rate for a given base case. A lean loading of 0.24 molCO{sub 2}/molMEA represents the best compromise at the chosen conditions between sufficient stripping and a limited amine flow rate. A temperature approach of the rich lean cross exchanger is investigated and a decrease in the temperature approach from 10 to 5{sup o}C results in a decrease in the reboiler heat duty of 2%. 8 refs., 4 figs.

  2. Optimization of physical factors affecting the production of thermo-stable organic solvent-tolerant protease from a newly isolated halo tolerant Bacillus subtilis strain Rand

    Directory of Open Access Journals (Sweden)

    Salleh Abu

    2009-04-01

    Full Text Available Abstract Background Many researchers have reported on the optimization of protease production; nevertheless, only a few have reported on the optimization of the production of organic solvent-tolerant proteases. Ironically, none has reported on thermostable organic solvent-tolerant protease to date. The aim of this study was to isolate the thermostable organic solvent-tolerant protease and identify the culture conditions which support its production. The bacteria of genus Bacillus are active producers of extra-cellular proteases, and the thermostability of enzyme production by Bacillus species has been well-studied by a number of researchers. In the present study, the Bacillus subtilis strain Rand was isolated from the contaminated soil found in Port Dickson, Malaysia. Results A thermostable organic solvent-tolerant protease producer had been identified as Bacillus subtilis strain Rand, based on the 16S rRNA analysis conducted, as well as the morphological characteristics and biochemical properties. The production of the thermostable organic solvent-tolerant protease was optimized by varying various physical culture conditions. Inoculation with 5.0% (v/v of (AB600 = 0.5 inoculum size, in a culture medium (pH 7.0 and incubated for 24 h at 37°C with 200 rpm shaking, was the best culture condition which resulted in the maximum growth and production of protease (444.7 U/ml; 4042.4 U/mg. The Rand protease was not only stable in the presence of organic solvents, but it also exhibited a higher activity than in the absence of organic solvent, except for pyridine which inhibited the protease activity. The enzyme retained 100, 99 and 80% of its initial activity, after the heat treatment for 30 min at 50, 55, and 60°C, respectively. Conclusion Strain Rand has been found to be able to secrete extra-cellular thermostable organic solvent-tolerant protease into the culture medium. The protease exhibited a remarkable stability towards temperature and organic

  3. Critical solvent properties affecting the particle formation process and characteristics of celecoxib-loaded PLGA microparticles via spray-drying

    DEFF Research Database (Denmark)

    Wan, Feng; Bohr, Adam; Maltesen, Morten Jonas

    2013-01-01

    ) microparticles prepared by spray-drying. METHODS: Binary mixtures of acetone and methanol at different molar ratios were applied to dissolve celecoxib and PLGA prior to spray-drying. The resulting microparticles were characterized with respect to morphology, texture, surface chemistry, solid state properties...... and drug release profile. The evaporation profiles of the feed solutions were investigated using thermogravimetric analysis (TGA). RESULTS: Spherical PLGA microparticles were obtained, irrespectively of the solvent composition. The particle size and surface chemistry were highly dependent on the solvent...

  4. Kinetics and Optimization of Lipophilic Kojic Acid Derivative Synthesis in Polar Aprotic Solvent Using Lipozyme RMIM and Its Rheological Study

    Directory of Open Access Journals (Sweden)

    Nurazwa Ishak

    2018-02-01

    Full Text Available The synthesis of kojic acid derivative (KAD from kojic and palmitic acid (C16:0 in the presence of immobilized lipase from Rhizomucor miehei (commercially known as Lipozyme RMIM, was studied using a shake flask system. Kojic acid is a polyfunctional heterocycles that acts as a source of nucleophile in this reaction allowing the formation of a lipophilic KAD. In this study, the source of biocatalyst, Lipozyme RMIM, was derived from the lipase of Rhizomucor miehei immobilized on weak anion exchange macro-porous Duolite ES 562 by the adsorption technique. The effects of solvents, enzyme loading, reaction temperature, and substrate molar ratio on the reaction rate were investigated. In one-factor-at-a-time (OFAT experiments, a high reaction rate (30.6 × 10−3 M·min−1 of KAD synthesis was recorded using acetone, enzyme loading of 1.25% (w/v, reaction time of 12 h, temperature of 50 °C and substrate molar ratio of 5:1. Thereafter, a yield of KAD synthesis was optimized via the response surface methodology (RSM whereby the optimized molar ratio (fatty acid: kojic acid, enzyme loading, reaction temperature and reaction time were 6.74, 1.97% (w/v, 45.9 °C, and 20 h respectively, giving a high yield of KAD (64.47%. This condition was reevaluated in a 0.5 L stirred tank reactor (STR where the agitation effects of two impellers; Rushton turbine (RT and pitch-blade turbine (PBT, were investigated. In the STR, a very high yield of KAD synthesis (84.12% was achieved using RT at 250 rpm, which was higher than the shake flask, thus indicating better mixing quality in STR. In a rheological study, a pseudoplastic behavior of KAD mixture was proposed for potential application in lotion formulation.

  5. Kinetics and Optimization of Lipophilic Kojic Acid Derivative Synthesis in Polar Aprotic Solvent Using Lipozyme RMIM and Its Rheological Study.

    Science.gov (United States)

    Ishak, Nurazwa; Lajis, Ahmad Firdaus B; Mohamad, Rosfarizan; Ariff, Arbakariya B; Mohamed, Mohd Shamzi; Halim, Murni; Wasoh, Helmi

    2018-02-24

    The synthesis of kojic acid derivative (KAD) from kojic and palmitic acid (C16:0) in the presence of immobilized lipase from Rhizomucor miehei (commercially known as Lipozyme RMIM), was studied using a shake flask system. Kojic acid is a polyfunctional heterocycles that acts as a source of nucleophile in this reaction allowing the formation of a lipophilic KAD. In this study, the source of biocatalyst, Lipozyme RMIM, was derived from the lipase of Rhizomucor miehei immobilized on weak anion exchange macro-porous Duolite ES 562 by the adsorption technique. The effects of solvents, enzyme loading, reaction temperature, and substrate molar ratio on the reaction rate were investigated. In one-factor-at-a-time (OFAT) experiments, a high reaction rate (30.6 × 10 -3 M·min -1 ) of KAD synthesis was recorded using acetone, enzyme loading of 1.25% ( w / v ), reaction time of 12 h, temperature of 50 °C and substrate molar ratio of 5:1. Thereafter, a yield of KAD synthesis was optimized via the response surface methodology (RSM) whereby the optimized molar ratio (fatty acid: kojic acid), enzyme loading, reaction temperature and reaction time were 6.74, 1.97% ( w / v ), 45.9 °C, and 20 h respectively, giving a high yield of KAD (64.47%). This condition was reevaluated in a 0.5 L stirred tank reactor (STR) where the agitation effects of two impellers; Rushton turbine (RT) and pitch-blade turbine (PBT), were investigated. In the STR, a very high yield of KAD synthesis (84.12%) was achieved using RT at 250 rpm, which was higher than the shake flask, thus indicating better mixing quality in STR. In a rheological study, a pseudoplastic behavior of KAD mixture was proposed for potential application in lotion formulation.

  6. Multi-level iteration optimization for diffusive critical calculation

    International Nuclear Information System (INIS)

    Li Yunzhao; Wu Hongchun; Cao Liangzhi; Zheng Youqi

    2013-01-01

    In nuclear reactor core neutron diffusion calculation, there are usually at least three levels of iterations, namely the fission source iteration, the multi-group scattering source iteration and the within-group iteration. Unnecessary calculations occur if the inner iterations are converged extremely tight. But the convergence of the outer iteration may be affected if the inner ones are converged insufficiently tight. Thus, a common scheme suit for most of the problems was proposed in this work to automatically find the optimized settings. The basic idea is to optimize the relative error tolerance of the inner iteration based on the corresponding convergence rate of the outer iteration. Numerical results of a typical thermal neutron reactor core problem and a fast neutron reactor core problem demonstrate the effectiveness of this algorithm in the variational nodal method code NODAL with the Gauss-Seidel left preconditioned multi-group GMRES algorithm. The multi-level iteration optimization scheme reduces the number of multi-group and within-group iterations respectively by a factor of about 1-2 and 5-21. (authors)

  7. Vapour permeation for the recovery of organic solvents from waste air streams: separation capacities and process optimization

    NARCIS (Netherlands)

    Leemann, M.; Leemann, M.; Eigenberger, G.; Strathmann, H.

    1996-01-01

    Vapour permeation is a potentially suitable technology for the recovery of organic solvents from waste air streams. New solvent stable capillary membrane modules that are currently emerging on the market provide large membrane areas for an acceptable price and enhance the competitiveness of this

  8. Truss optimization with discrete design variables: a critical review

    DEFF Research Database (Denmark)

    Stolpe, Mathias

    2016-01-01

    problems. This, and other, observations lead to a set of recommended research tasks and objectives to bring the field forward. The development of a publicly available benchmark library is urgently needed to support development and assessment of existing and new heuristics and methods. Combined...... methods and meta heuristics. The field has experienced a shift in focus from deterministic methods to meta heuristics, i.e. stochastic search methods. Based on the reported numerical results it is however not possible to conclude that this shift has improved the competences to solve application relevant...... with this effort, it is recommended that the field begins to use modern methods such as performance profiles for fair and accurate comparison of optimization methods. Finally, theoretical results are rare in this field. This means that most recent methods and heuristics are not supported by mathematical theory...

  9. Optimization of oil yield from Hevea brasiliensis seeds through ultrasonic-assisted solvent extraction via response surface methodology

    Directory of Open Access Journals (Sweden)

    Val Irvin F. Mabayo

    2018-01-01

    Full Text Available The demand for oil has been increasing vastly over time, and the source of this has slowly been diminishing. The use of non-food feedstock is seen as a promising alternative source for the production of bio-based fuel. In this study, rubber (Hevea brasiliensis seeds were utilized as biomass in bio-oil production considering that these are non-edible and considered wastes in rubber tree plantations. In the oil extraction process, the rubber seed kernels were oven dried at 100 °C for 24 h, powdered and then dried further at 105 °C for 4 h. After characterization, optimization study was done using Design Expert 7.0 software through central composite design of the response surface methodology. Ultrasonication technology was employed in the oil extraction process which significantly reduced the reaction time needed for extraction to 15 min compared the conventional extraction method of at least 8 h. An optimum rubber seed oil (RSO yield of 30.3 ± 0.3% was obtained using 15 g biomass, 5:1 n-hexane to biomass (mL g−1 ratio, 50 μm resonance amplitude and 60 ± 5 °C temperature at 15 min reaction time. The oil yield at optimum condition was found to have 0.89 g mL−1 density at room temperature, 26.7 cSt kinematic viscosity at 40 °C and high heating value of 39.2 MJ kg−1. The Fourier Transform Infrared Radiation spectroscopy analysis of the RSO, at optimum condition, showed the presence of carboxylic acid and ester carbonyl functional groups which are good indicators as a potential source of biodiesel. Keywords: Hevea brasiliensis, Oil extraction, Optimization, Response surface methodology, Rubber seed oil, Ultrasonic-assisted solvent extraction

  10. Optimal critic learning for robot control in time-varying environments.

    Science.gov (United States)

    Wang, Chen; Li, Yanan; Ge, Shuzhi Sam; Lee, Tong Heng

    2015-10-01

    In this paper, optimal critic learning is developed for robot control in a time-varying environment. The unknown environment is described as a linear system with time-varying parameters, and impedance control is employed for the interaction control. Desired impedance parameters are obtained in the sense of an optimal realization of the composite of trajectory tracking and force regulation. Q -function-based critic learning is developed to determine the optimal impedance parameters without the knowledge of the system dynamics. The simulation results are presented and compared with existing methods, and the efficacy of the proposed method is verified.

  11. In silico optimization of critical currents in superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kimmel, Gregory; Sadovskyy, Ivan A.; Glatz, Andreas

    2017-07-01

    For many technological applications of superconductors the performance of a material is determined by the highest current it can carry losslessly-the critical current. In turn, the critical current can be controlled by adding nonsuperconducting defects in the superconductor matrix. Here we report on systematic comparison of different local and global optimization strategies to predict optimal structures of pinning centers leading to the highest possible critical currents. We demonstrate performance of these methods for a superconductor with randomly placed spherical, elliptical, and columnar defects.

  12. The hybrid MPC-MINLP algorithm for optimal operation of coal-fired power plants with solvent based post-combustion CO2 capture

    Directory of Open Access Journals (Sweden)

    Norhuda Abdul Manaf

    2017-03-01

    Full Text Available This paper presents an algorithm that combines model predictive control (MPC with MINLP optimization and demonstrates its application for coal-fired power plants retrofitted with solvent based post-combustion CO2 capture (PCC plant. The objective function of the optimization algorithm works at a primary level to maximize plant economic revenue while considering an optimal carbon capture profile. At a secondary level, the MPC algorithm is used to control the performance of the PCC plant. Two techno-economic scenarios based on fixed (capture rate is constant and flexible (capture rate is variable operation modes are developed using actual electricity prices (2011 with fixed carbon prices ($AUD 5, 25, 50/tonne-CO2 for 24 h periods. Results show that fixed operation mode can bring about a ratio of net operating revenue deficit at an average of 6% against the superior flexible operation mode.

  13. Critical overview of the development of the optimization requirement and its implementation

    International Nuclear Information System (INIS)

    Gonzalez, A.J.

    1988-01-01

    This paper is intended to provide a critical overview of the development of the optimization requirement of the system of dose limitation recommended by the International Commission on Radiological Protection (ICRP), as well as of its implementation. The concept of optimization began to evolve in the mid-1950s and was formally introduced as a requirement for radiation protection in 1978. Recommendations on its practical implementation have been available for five years. After such a long evolution, it seems reasonable to make a critical assessment of the development of the optimization concept, and this summary paper is intended to provide such an assessment. It does not include a description of the requirement or of any method for implementing it, since it is assumed that optimization is familiar by now. The paper concentrates rather on misunderstandings of and achievements owed to optimization and explores some of their underlying causes, the intention being to draw lessons from past experience and to apply them to future developments in this area. The paper presents an outlook on some remaining policy issues that still pending solution as well as some suggestions on prioritization of implementation of optimization and on standardizing the optimization protection

  14. Sub-critical water as a green solvent for production of valuable materials from agricultural waste biomass: A review of recent work

    Directory of Open Access Journals (Sweden)

    A. Shitu

    2015-07-01

    Full Text Available Agricultural waste biomass generated from agricultural production and food processing industry are abundant, such as durian  peel, mango peel, corn straw, rice bran, corn shell, potato peel and many more. Due to low commercial value, these wastes are disposed in landfill, which if not managed properly may cause environmental problems. Currently, environmental laws and regulations pertaining to the pollution from agricultural waste streams by regulatory agencies are stringent and hence the application of toxic solvents during processing has become public concern. Recent development in valuable materials extraction from the decomposition of agricultural waste by sub-critical water treatment from the published literature was review. Physico-chemical characteristic (reaction temperature, reaction time and solid to liquid ratio of the sub-critical water affecting its yield were also reviewed. The utilization of biomass residue from agriculture, forest wood production and from food and feed processing industry may be an important alternative renewable energy supply. The paper also presents future research on sub-critical water.

  15. Are optimal CO2 emissions really optimal? Four critical issues for economists in the greenhouse

    International Nuclear Information System (INIS)

    Azar, C.

    1998-01-01

    Although the greenhouse effect is by many considered as one of the most serious environmental problems, several economic studies of the greenhouse effect, most notably Nordhaus's DICE model, suggest that it is optimal to allow the emissions of greenhouse gases (GHG) to increase by a factor of three over the next century. Other studies have found that substantial reductions can be justified on economic grounds. This paper explores into the reasons for these differences and identifies four (partly overlapping) crucial issues that have to be dealt with when analysing the economics of the greenhouse effect low-probability but catastrophic events; cost evaluation methods; the choice of discount rate; the choice of decision criterion. The paper shows that (1) these aspects are crucial for the policy conclusions drawn from models of the economics of climate change, and that (2) ethical choices have to be made for each of these issues. This fact needs wider recognition since economics is very often perceived as a value neutral tool that can be used to provide policy makers with 'optimal' policies. 62 refs

  16. Adaptive Inverse Optimal Control for Rehabilitation Robot Systems Using Actor-Critic Algorithm

    Directory of Open Access Journals (Sweden)

    Fancheng Meng

    2014-01-01

    Full Text Available The higher goal of rehabilitation robot is to aid a person to achieve a desired functional task (e.g., tracking trajectory based on assisted-as-needed principle. To this goal, a new adaptive inverse optimal hybrid control (AHC combining inverse optimal control and actor-critic learning is proposed. Specifically, an uncertain nonlinear rehabilitation robot model is firstly developed that includes human motor behavior dynamics. Then, based on this model, an open-loop error system is formed; thereafter, an inverse optimal control input is designed to minimize the cost functional and a NN-based actor-critic feedforward signal is responsible for the nonlinear dynamic part contaminated by uncertainties. Finally, the AHC controller is proven (through a Lyapunov-based stability analysis to yield a global uniformly ultimately bounded stability result, and the resulting cost functional is meaningful. Simulation and experiment on rehabilitation robot demonstrate the effectiveness of the proposed control scheme.

  17. SWANS: A Prototypic SCALE Criticality Sequence for Automated Optimization Using the SWAN Methodology

    International Nuclear Information System (INIS)

    Greenspan, E.

    2001-01-01

    SWANS is a new prototypic analysis sequence that provides an intelligent, semi-automatic search for the maximum k eff of a given amount of specified fissile material, or of the minimum critical mass. It combines the optimization strategy of the SWAN code with the composition-dependent resonance self-shielded cross sections of the SCALE package. For a given system composition arrived at during the iterative optimization process, the value of k eff is as accurate and reliable as obtained using the CSAS1X Sequence of SCALE-4.4. This report describes how SWAN is integrated within the SCALE system to form the new prototypic optimization sequence, describes the optimization procedure, provides a user guide for SWANS, and illustrates its application to five different types of problems. In addition, the report illustrates that resonance self-shielding might have a significant effect on the maximum k eff value a given fissile material mass can have

  18. Adaptive critic designs for optimal control of uncertain nonlinear systems with unmatched interconnections.

    Science.gov (United States)

    Yang, Xiong; He, Haibo

    2018-05-26

    In this paper, we develop a novel optimal control strategy for a class of uncertain nonlinear systems with unmatched interconnections. To begin with, we present a stabilizing feedback controller for the interconnected nonlinear systems by modifying an array of optimal control laws of auxiliary subsystems. We also prove that this feedback controller ensures a specified cost function to achieve optimality. Then, under the framework of adaptive critic designs, we use critic networks to solve the Hamilton-Jacobi-Bellman equations associated with auxiliary subsystem optimal control laws. The critic network weights are tuned through the gradient descent method combined with an additional stabilizing term. By using the newly established weight tuning rules, we no longer need the initial admissible control condition. In addition, we demonstrate that all signals in the closed-loop auxiliary subsystems are stable in the sense of uniform ultimate boundedness by using classic Lyapunov techniques. Finally, we provide an interconnected nonlinear plant to validate the present control scheme. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Parametric Optimization of Some Critical Operating System Functions--An Alternative Approach to the Study of Operating Systems Design

    Science.gov (United States)

    Sobh, Tarek M.; Tibrewal, Abhilasha

    2006-01-01

    Operating systems theory primarily concentrates on the optimal use of computing resources. This paper presents an alternative approach to teaching and studying operating systems design and concepts by way of parametrically optimizing critical operating system functions. Detailed examples of two critical operating systems functions using the…

  20. Actor-critic-based optimal tracking for partially unknown nonlinear discrete-time systems.

    Science.gov (United States)

    Kiumarsi, Bahare; Lewis, Frank L

    2015-01-01

    This paper presents a partially model-free adaptive optimal control solution to the deterministic nonlinear discrete-time (DT) tracking control problem in the presence of input constraints. The tracking error dynamics and reference trajectory dynamics are first combined to form an augmented system. Then, a new discounted performance function based on the augmented system is presented for the optimal nonlinear tracking problem. In contrast to the standard solution, which finds the feedforward and feedback terms of the control input separately, the minimization of the proposed discounted performance function gives both feedback and feedforward parts of the control input simultaneously. This enables us to encode the input constraints into the optimization problem using a nonquadratic performance function. The DT tracking Bellman equation and tracking Hamilton-Jacobi-Bellman (HJB) are derived. An actor-critic-based reinforcement learning algorithm is used to learn the solution to the tracking HJB equation online without requiring knowledge of the system drift dynamics. That is, two neural networks (NNs), namely, actor NN and critic NN, are tuned online and simultaneously to generate the optimal bounded control policy. A simulation example is given to show the effectiveness of the proposed method.

  1. Design Optimization of Mixed-Criticality Real-Time Applications on Cost-Constrained Partitioned Architectures

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian; Pop, Paul

    2011-01-01

    In this paper we are interested to implement mixed-criticality hard real-time applications on a given heterogeneous distributed architecture. Applications have different criticality levels, captured by their Safety-Integrity Level (SIL), and are scheduled using static-cyclic scheduling. Mixed......-criticality tasks can be integrated onto the same architecture only if there is enough spatial and temporal separation among them. We consider that the separation is provided by partitioning, such that applications run in separate partitions, and each partition is allocated several time slots on a processor. Tasks...... slots on each processor and (iv) the schedule tables, such that all the applications are schedulable and the development costs are minimized. We have proposed a Tabu Search-based approach to solve this optimization problem. The proposed algorithm has been evaluated using several synthetic and real...

  2. Design of optimal solvent for extraction of bio–active ingredients from six varieties of Medicago sativa

    Directory of Open Access Journals (Sweden)

    Caunii Angela

    2012-10-01

    Full Text Available Abstract Background Extensive research has been performed worldwide and important evidences were collected to show the immense potential of plants used in various traditional therapeutic systems. The aim of this work is to investigate the different extracting solvents in terms of the influence of their polarity on the extracting ability of bioactive molecules (phenolic compounds from the M. sativa flowers. Results The total phenolic content of samples was determined using the Folin Ciocalteu (FC procedure and their antioxidant activity was assayed through in vitro radical decomposing activity using the radical DPPH° assay (IUPAC name for DPPH is (phenyl–(2,4,6–trinitrophenyl iminoazanium. The results showed that water was better than methanol and acetic acid for extracting bioactive compounds, in particular for total phenolic compounds from the flowers of alfalfa. The average content of bioactive molecules in methanol extract was 263.5±1.02 mg GAE/100g of dry weight lyophilized extract. The total phenolic content of the tested plant extracts was highly correlated with the radical decomposing activity. However, all extracts were free–radical inhibitors, but the water extract was more potent than the acetic and the methanol ones. The order of inhibitor effectiveness (expressed by IC50 proved to be: water extract (0.924mg/mL > acetic acid extract (0.154mg/mL > methanol (0.079mg/mL. The profiles of each extract (fingerprint were characterized by FT–MIR spectroscopy. Conclusions The present study compares the fingerprint of different extracts of the M. sativa flowers, collected from the wild flora of Romania. The total phenolic content of the tested plant extracts was highly correlated with the radical decomposing activity. The dependence of the extract composition on the solvent polarity (acetic acid vs. methanol vs. water was revealed by UV–VIS spectrometry and Infrared fingerprint.

  3. Solvent selection and optimization of α-chymotrypsin-catalyzed synthesis of N-Ac-Phe-Tyr-NH2 using mixture design and response surface methodology.

    Science.gov (United States)

    Hu, Shih-Hao; Kuo, Chia-Hung; Chang, Chieh-Ming J; Liu, Yung-Chuan; Chiang, Wen-Dee; Shieh, Chwen-Jen

    2012-01-01

    A peptide, N-Ac-Phe-Tyr-NH(2) , with angiotensin I-converting enzyme (ACE) inhibitor activity was synthesized by an α-chymotrypsin-catalyzed condensation reaction of N-acetyl phenylalanine ethyl ester (N-Ac-Phe-OEt) and tyrosinamide (Tyr-NH(2) ). Three kinds of solvents: a Tris-HCl buffer (80 mM, pH 9.0), dimethylsulfoxide (DMSO), and acetonitrile were employed in this study. The optimum reaction solvent component was determined by simplex centroid mixture design. The synthesis efficiency was enhanced in an organic-aqueous solvent (Tris-HCl buffer: DMSO: acetonitrile = 2:1:1) in which 73.55% of the yield of N-Ac-Phe-Tyr-NH(2) could be achieved. Furthermore, the effect of reaction parameters on the yield was evaluated by response surface methodology (RSM) using a central composite rotatable design (CCRD). Based on a ridge max analysis, the optimum condition for this peptide synthesis included a reaction time of 7.4 min, a reaction temperature of 28.1°C, an enzyme activity of 98.9 U, and a substrate molar ratio (Phe:Tyr) of 1:2.8. The predicted and the actual (experimental) yields were 87.6 and 85.5%, respectively. The experimental design and RSM performed well in the optimization of synthesis of N-Ac-Phe-Tyr-NH(2) , so it is expected to be an effective method for obtaining a good yield of enzymatic peptide. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  4. Optimizing gradient conditions in online comprehensive two-dimensional reversed-phase liquid chromatography by use of the linear solvent strength model

    DEFF Research Database (Denmark)

    Græsbøll, Rune; Janssen, Hans-Gerd; Christensen, Jan H.

    2017-01-01

    The linear solvent strength model was used to predict coverage in online comprehensive two-dimensional reversed-phase liquid chromatography. The prediction model uses a parallelogram to describe the separation space covered with peaks in a system with limited orthogonality. The corners of the par......The linear solvent strength model was used to predict coverage in online comprehensive two-dimensional reversed-phase liquid chromatography. The prediction model uses a parallelogram to describe the separation space covered with peaks in a system with limited orthogonality. The corners...... of the parallelogram are assumed to behave like chromatographic peaks and the position of these pseudo-compounds was predicted. A mix of 25 polycyclic aromatic compounds were used as a test. The precision of the prediction, span 0-25, was tested by varying input parameters, and was found to be acceptable with root...... factors were low, or when gradient conditions affected parameters not included in the model, e.g. second dimension gradient time affects the second dimension equilibration time. The concept shows promise as a tool for gradient optimization in online comprehensive two-dimensional liquid chromatography...

  5. Deasphalting solvents

    International Nuclear Information System (INIS)

    Carrillo, J. A; Caceres, J; Vela, G; Bueno, H

    1996-01-01

    This paper describes how the deasphalted oil (DMO) or demetalized oil (DMO) quality (CCR, Ni, V end asphaltenes contents) changes with: DAO or DMO yield, solvent/feed ratio, type of vacuum reside (from paraffinic to blends with vis breaking bottoms), extraction temperature and extraction solvent (propane, propylene, n-butane and I butane)

  6. Optimizing mission critical data dissemination in massive IoT networks

    KAUST Repository

    Farooq, Muhammad Junaid

    2017-06-29

    Mission critical data dissemination in massive Internet of things (IoT) networks imposes constraints on the message transfer delay between devices. Due to low power and communication range of IoT devices, data is foreseen to be relayed over multiple device-to-device (D2D) links before reaching the destination. The coexistence of a massive number of IoT devices poses a challenge in maximizing the successful transmission capacity of the overall network alongside reducing the multi-hop transmission delay in order to support mission critical applications. There is a delicate interplay between the carrier sensing threshold of the contention based medium access protocol and the choice of packet forwarding strategy selected at each hop by the devices. The fundamental problem in optimizing the performance of such networks is to balance the tradeoff between conflicting performance objectives such as the spatial frequency reuse, transmission quality, and packet progress towards the destination. In this paper, we use a stochastic geometry approach to quantify the performance of multi-hop massive IoT networks in terms of the spatial frequency reuse and the transmission quality under different packet forwarding schemes. We also develop a comprehensive performance metric that can be used to optimize the system to achieve the best performance. The results can be used to select the best forwarding scheme and tune the carrier sensing threshold to optimize the performance of the network according to the delay constraints and transmission quality requirements.

  7. Solvent substitution

    International Nuclear Information System (INIS)

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general ''Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated

  8. Solvent substitution

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.

  9. Hit Identification and Optimization in Virtual Screening: Practical Recommendations Based Upon a Critical Literature Analysis

    Science.gov (United States)

    Zhu, Tian; Cao, Shuyi; Su, Pin-Chih; Patel, Ram; Shah, Darshan; Chokshi, Heta B.; Szukala, Richard; Johnson, Michael E.; Hevener, Kirk E.

    2013-01-01

    A critical analysis of virtual screening results published between 2007 and 2011 was performed. The activity of reported hit compounds from over 400 studies was compared to their hit identification criteria. Hit rates and ligand efficiencies were calculated to assist in these analyses and the results were compared with factors such as the size of the virtual library and the number of compounds tested. A series of promiscuity, drug-like, and ADMET filters were applied to the reported hits to assess the quality of compounds reported and a careful analysis of a subset of the studies which presented hit optimization was performed. This data allowed us to make several practical recommendations with respect to selection of compounds for experimental testing, defining hit identification criteria, and general virtual screening hit criteria to allow for realistic hit optimization. A key recommendation is the use of size-targeted ligand efficiency values as hit identification criteria. PMID:23688234

  10. Hit identification and optimization in virtual screening: practical recommendations based on a critical literature analysis.

    Science.gov (United States)

    Zhu, Tian; Cao, Shuyi; Su, Pin-Chih; Patel, Ram; Shah, Darshan; Chokshi, Heta B; Szukala, Richard; Johnson, Michael E; Hevener, Kirk E

    2013-09-12

    A critical analysis of virtual screening results published between 2007 and 2011 was performed. The activity of reported hit compounds from over 400 studies was compared to their hit identification criteria. Hit rates and ligand efficiencies were calculated to assist in these analyses, and the results were compared with factors such as the size of the virtual library and the number of compounds tested. A series of promiscuity, druglike, and ADMET filters were applied to the reported hits to assess the quality of compounds reported, and a careful analysis of a subset of the studies that presented hit optimization was performed. These data allowed us to make several practical recommendations with respect to selection of compounds for experimental testing, definition of hit identification criteria, and general virtual screening hit criteria to allow for realistic hit optimization. A key recommendation is the use of size-targeted ligand efficiency values as hit identification criteria.

  11. Critical evaluation and thermodynamic optimization of the U-Pb and U-Sb binary systems

    International Nuclear Information System (INIS)

    Wang, Jian; Jin, Liling; Chen, Chuchu; Rao, Weifeng; Wang, Cuiping; Liu, Xingjun

    2016-01-01

    A complete literature review, critical evaluation and thermodynamic optimization of the phase diagrams and thermodynamic properties of U-Pb and U-Sb binary systems are presented. The CALculation of PHAse Diagrams (CALPHAD) method was used for the thermodynamic optimization, the results of which can reproduce all available reliable experimental phase equilibria and thermodynamic data. The modified quasi-chemical model in the pair approximation (MQMPA) was used for modeling the liquid solution. The Gibbs energies of all terminal solid solutions and intermetallic compounds were described by the compound energy formalism (CEF) model. All reliable experimental data of the U-Pb and U-Sb systems have been reproduced. A self-consistent thermodynamic database has been constructed for these binary systems; this database can be used in liquid-metal fuel reactor (LMFR) research.

  12. Off-Policy Actor-Critic Structure for Optimal Control of Unknown Systems With Disturbances.

    Science.gov (United States)

    Song, Ruizhuo; Lewis, Frank L; Wei, Qinglai; Zhang, Huaguang

    2016-05-01

    An optimal control method is developed for unknown continuous-time systems with unknown disturbances in this paper. The integral reinforcement learning (IRL) algorithm is presented to obtain the iterative control. Off-policy learning is used to allow the dynamics to be completely unknown. Neural networks are used to construct critic and action networks. It is shown that if there are unknown disturbances, off-policy IRL may not converge or may be biased. For reducing the influence of unknown disturbances, a disturbances compensation controller is added. It is proven that the weight errors are uniformly ultimately bounded based on Lyapunov techniques. Convergence of the Hamiltonian function is also proven. The simulation study demonstrates the effectiveness of the proposed optimal control method for unknown systems with disturbances.

  13. SWANS: A Prototypic SCALE Criticality Sequence for Automated Optimization Using the SWAN Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Greenspan, E.

    2001-01-11

    SWANS is a new prototypic analysis sequence that provides an intelligent, semi-automatic search for the maximum k{sub eff} of a given amount of specified fissile material, or of the minimum critical mass. It combines the optimization strategy of the SWAN code with the composition-dependent resonance self-shielded cross sections of the SCALE package. For a given system composition arrived at during the iterative optimization process, the value of k{sub eff} is as accurate and reliable as obtained using the CSAS1X Sequence of SCALE-4.4. This report describes how SWAN is integrated within the SCALE system to form the new prototypic optimization sequence, describes the optimization procedure, provides a user guide for SWANS, and illustrates its application to five different types of problems. In addition, the report illustrates that resonance self-shielding might have a significant effect on the maximum k{sub eff} value a given fissile material mass can have.

  14. Optimization of superconductor--normal-metal--superconductor Josephson junctions for high critical-current density

    International Nuclear Information System (INIS)

    Golub, A.; Horovitz, B.

    1994-01-01

    The application of superconducting Bi 2 Sr 2 CaCu 2 O 8 and YBa 2 Cu 3 O 7 wires or tapes to electronic devices requires the optimization of the transport properties in Ohmic contacts between the superconductor and the normal metal in the circuit. This paper presents results of tunneling theory in superconductor--normal-metal--superconductor (SNS) junctions, in both pure and dirty limits. We derive expressions for the critical-current density as a function of the normal-metal resistivity in the dirty limit or of the ratio of Fermi velocities and effective masses in the clean limit. In the latter case the critical current increases when the ratio γ of the Fermi velocity in the superconductor to that of the weak link becomes much less than 1 and it also has a local maximum if γ is close to 1. This local maximum is more pronounced if the ratio of effective masses is large. For temperatures well below the critical temperature of the superconductors the model with abrupt pair potential on the SN interfaces is considered and its applicability near the critical temperature is examined

  15. A critical evaluation of worst case optimization methods for robust intensity-modulated proton therapy planning

    International Nuclear Information System (INIS)

    Fredriksson, Albin; Bokrantz, Rasmus

    2014-01-01

    Purpose: To critically evaluate and compare three worst case optimization methods that have been previously employed to generate intensity-modulated proton therapy treatment plans that are robust against systematic errors. The goal of the evaluation is to identify circumstances when the methods behave differently and to describe the mechanism behind the differences when they occur. Methods: The worst case methods optimize plans to perform as well as possible under the worst case scenario that can physically occur (composite worst case), the combination of the worst case scenarios for each objective constituent considered independently (objectivewise worst case), and the combination of the worst case scenarios for each voxel considered independently (voxelwise worst case). These three methods were assessed with respect to treatment planning for prostate under systematic setup uncertainty. An equivalence with probabilistic optimization was used to identify the scenarios that determine the outcome of the optimization. Results: If the conflict between target coverage and normal tissue sparing is small and no dose-volume histogram (DVH) constraints are present, then all three methods yield robust plans. Otherwise, they all have their shortcomings: Composite worst case led to unnecessarily low plan quality in boundary scenarios that were less difficult than the worst case ones. Objectivewise worst case generally led to nonrobust plans. Voxelwise worst case led to overly conservative plans with respect to DVH constraints, which resulted in excessive dose to normal tissue, and less sharp dose fall-off than the other two methods. Conclusions: The three worst case methods have clearly different behaviors. These behaviors can be understood from which scenarios that are active in the optimization. No particular method is superior to the others under all circumstances: composite worst case is suitable if the conflicts are not very severe or there are DVH constraints whereas

  16. Critical phenomena in communication/computation networks with various topologies and suboptimal to optimal resource allocation

    Science.gov (United States)

    Cogoni, Marco; Busonera, Giovanni; Anedda, Paolo; Zanetti, Gianluigi

    2015-01-01

    We generalize previous studies on critical phenomena in communication networks [1,2] by adding computational capabilities to the nodes. In our model, a set of tasks with random origin, destination and computational structure is distributed on a computational network, modeled as a graph. By varying the temperature of a Metropolis Montecarlo, we explore the global latency for an optimal to suboptimal resource assignment at a given time instant. By computing the two-point correlation function for the local overload, we study the behavior of the correlation distance (both for links and nodes) while approaching the congested phase: a transition from peaked to spread g(r) is seen above a critical (Montecarlo) temperature Tc. The average latency trend of the system is predicted by averaging over several network traffic realizations while maintaining a spatially detailed information for each node: a sharp decrease of performance is found over Tc independently of the workload. The globally optimized computational resource allocation and network routing defines a baseline for a future comparison of the transition behavior with respect to existing routing strategies [3,4] for different network topologies.

  17. Measurement of the main and critical parameters for optimal laser treatment of heart disease

    Science.gov (United States)

    Kabeya, FB; Abrahamse, H.; Karsten, AE

    2017-10-01

    Laser light is frequently used in the diagnosis and treatment of patients. As in traditional treatments such as medication, bypass surgery, and minimally invasive ways, laser treatment can also fail and present serious side effects. The true reason for laser treatment failure or the side effects thereof, remains unknown. From the literature review conducted, and experimental results generated we conclude that an optimal laser treatment for coronary artery disease (named heart disease) can be obtained if certain critical parameters are correctly measured and understood. These parameters include the laser power, the laser beam profile, the fluence rate, the treatment time, as well as the absorption and scattering coefficients of the target treatment tissue. Therefore, this paper proposes different, accurate methods for the measurement of these critical parameters to determine the optimal laser treatment of heart disease with a minimal risk of side effects. The results from the measurement of absorption and scattering properties can be used in a computer simulation package to predict the fluence rate. The computing technique is a program based on the random number (Monte Carlo) process and probability statistics to track the propagation of photons through a biological tissue.

  18. [Optimal energy supply in different age groups of critically ill children on mechanical ventilation].

    Science.gov (United States)

    Li, X H; Ji, J; Qian, S Y

    2018-01-02

    Objective: To analyze the resting energy expenditure and optimal energy supply in different age groups of critically ill children on mechanical ventilation in pediatric intensive care unit (PICU). Methods: Patients on mechanical ventilation hospitalized in PICU of Beijing Children's Hospital from March 2015 to March 2016 were enrolled prospectively. Resting energy expenditure of patients was calculated by US Med Graphic company critical care management (CCM) energy metabolism test system after mechanical ventilation. Patients were divided into three groups:10 years. The relationship between the measured and predictive resting energy expenditure was analyzed with correlation analysis; while the metabolism status and the optimal energy supply in different age groups were analyzed with chi square test and variance analysis. Results: A total of 102 patients were enrolled, the measured resting energy expenditure all correlated with predictive resting energy expenditure in different age groups (10 years ( r= 0.5, P= 0.0) ) . A total of 40 cases in group, including: 14 cases of low metabolism (35%), 14 cases of normal metabolism (35%), and 12 cases of high metabolism (30%); 45 cases in 3-10 years group, including: 22 cases of low metabolism (49%), 19 cases of normal metabolism (42%), 4 cases of high metabolism (9%); 17 cases in > 10 years group, including: 12 cases of low metabolism (71%), 4 cases of normal metabolism (23%), 1 case of high metabolism (6%). Metabolism status showed significant differences between different age groups ( χ (2)=11.30, P age groups ( F= 46.57, Pgroup, (184±53) kJ/ (kg⋅d) in 3-10 years group, and (120±30) kJ/ (kg⋅d) in > 10 years group. Conclusion: The resting energy metabolism of the critically ill children on mechanical ventilation is negatively related to the age. The actual energy requirement should be calculated according to different ages.

  19. Optimization of Multiple Seepage Piping Parameters to Maximize the Critical Hydraulic Gradient in Bimsoils

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2017-10-01

    Full Text Available Seepage failure in the form of piping can strongly influence the stability of block-in-matrix-soils (bimsoils, as well as weaken and affect the performance of bimsoil structures. The multiple-factor evaluation and optimization play a crucial role in controlling the seepage failure in bimsoil. The aim of this study is to improve the ability to control the piping seepage failure in bimsoil. In this work, the response surface method (RSM was employed to evaluate and optimize the multiple piping parameters to maximize the critical hydraulic gradient (CHG, in combination with experimental modeling based on a self-developed servo-controlled flow-erosion-stress coupled testing system. All of the studied specimens with rock block percentage (RBP of 30%, 50%, and 70% were produced as a cylindrical shape (50 mm diameter and 100 mm height by compaction tests. Four uncertain parameters, such as RBP, soil matrix density, confining pressure, and block morphology were used to fit an optimal response of the CHG. The sensitivity analysis reveals the influential order of the studied factors to CHG. It is found that RBP is the most sensitive factor, the CHG decreases with the increase of RBP, and CHG increases with the increase of confining pressure, soil matrix density, and block angularity.

  20. Analytical study on the criticality of the stochastic optimal velocity model

    International Nuclear Information System (INIS)

    Kanai, Masahiro; Nishinari, Katsuhiro; Tokihiro, Tetsuji

    2006-01-01

    In recent works, we have proposed a stochastic cellular automaton model of traffic flow connecting two exactly solvable stochastic processes, i.e., the asymmetric simple exclusion process and the zero range process, with an additional parameter. It is also regarded as an extended version of the optimal velocity model, and moreover it shows particularly notable properties. In this paper, we report that when taking optimal velocity function to be a step function, all of the flux-density graph (i.e. the fundamental diagram) can be estimated. We first find that the fundamental diagram consists of two line segments resembling an inversed-λ form, and next identify their end-points from a microscopic behaviour of vehicles. It is notable that by using a microscopic parameter which indicates a driver's sensitivity to the traffic situation, we give an explicit formula for the critical point at which a traffic jam phase arises. We also compare these analytical results with those of the optimal velocity model, and point out the crucial differences between them

  1. Solvent substitutes

    International Nuclear Information System (INIS)

    Evanoff, S.P.

    1995-01-01

    The environmental and industrial hygiene regulations promulgated since 1980, most notably the Superfund Amendments and Reauthorization Act (SARA), the Hazardous and Solid Waste Amendments to the Resources Conservation and Recovery Act (RCRA), and the Clean Air Act Amendments of 1990, have brought about an increased emphasis on user exposure, hazardous waste generation, and air emissions. As a result, industry is performing a fundamental reassessment of cleaning solvents, processes, and procedures. The more progressive organizations have made their goal the elimination of solvents that may pose significant potential human health and environmental hazards. This chapter discusses solvent cleaning in metal-finishing, metal-manufacturing, and industrial maintenance applications; precision cleaning; and electronics manufacturing. Nonmetallic cleaning, adhesives, coatings, inks, and aerosols also will be addressed, but in a more cursory manner

  2. Analysis and Optimization of Mixed-Criticality Applications on Partitioned Distributed Architectures

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian; Marinescu, S. O.; Pop, Paul

    2012-01-01

    Constrained (RC) messages, transmitted if there are no TT messages, and Best Effort (BE) messages. We assume that applications are scheduled using Static Cyclic Scheduling (SCS) or Fixed-Priority Preemptive Scheduling (FPS). We are interested in analysis and optimization methods and tools, which decide...... within predefined time slots, allocated on each processor. At the communication-level, TTEthernet uses the concepts of virtual links for the separation of mixed-criticality messages. TTEthernet integrates three types of traffic: Time-Triggered (TT) messages, transmitted based on schedule tables, Rate...... the mapping of tasks to PEs, the sequence and length of the time partitions on each PE and the schedule tables of the SCS tasks and TT messages, such that the applications are schedulable and the response times of FPS tasks and RC messages is minimized. We have proposed a Tabu Search-based meta...

  3. Optimizing critical heat flux enhancement through nano-particle-based surface modifications

    International Nuclear Information System (INIS)

    Truong, B.; Hu, L. W.; Buongiorno, J.

    2008-01-01

    Colloidal dispersions of nano-particles, also known as nano-fluids, have shown to yield significant Critical Heat Flux (CHF) enhancement. The CHF enhancement mechanism in nano-fluids is due to the buildup of a porous layer of nano-particles upon boiling. Unlike microporous coatings that had been studied extensively, nano-particles have the advantages of forming a thin layer on the substrate with surface roughness ranges from the sub-micron to several microns. By tuning the chemical properties it is possible to coat the nano-particles in colloidal dispersions onto the desired surface, as has been demonstrated in engineering thin film industry. Building on recent work conducted at MIT, this paper illustrates the maximum CHF enhancement that can be achieved based on existing correlations. Optimization of the CHF enhancement by incorporation of key factors, such as the surface wettability and roughness, will also be discussed. (authors)

  4. Adaptive Constrained Optimal Control Design for Data-Based Nonlinear Discrete-Time Systems With Critic-Only Structure.

    Science.gov (United States)

    Luo, Biao; Liu, Derong; Wu, Huai-Ning

    2018-06-01

    Reinforcement learning has proved to be a powerful tool to solve optimal control problems over the past few years. However, the data-based constrained optimal control problem of nonaffine nonlinear discrete-time systems has rarely been studied yet. To solve this problem, an adaptive optimal control approach is developed by using the value iteration-based Q-learning (VIQL) with the critic-only structure. Most of the existing constrained control methods require the use of a certain performance index and only suit for linear or affine nonlinear systems, which is unreasonable in practice. To overcome this problem, the system transformation is first introduced with the general performance index. Then, the constrained optimal control problem is converted to an unconstrained optimal control problem. By introducing the action-state value function, i.e., Q-function, the VIQL algorithm is proposed to learn the optimal Q-function of the data-based unconstrained optimal control problem. The convergence results of the VIQL algorithm are established with an easy-to-realize initial condition . To implement the VIQL algorithm, the critic-only structure is developed, where only one neural network is required to approximate the Q-function. The converged Q-function obtained from the critic-only VIQL method is employed to design the adaptive constrained optimal controller based on the gradient descent scheme. Finally, the effectiveness of the developed adaptive control method is tested on three examples with computer simulation.

  5. Implementation of quality by design principles in the development of microsponges as drug delivery carriers: Identification and optimization of critical factors using multivariate statistical analyses and design of experiments studies.

    Science.gov (United States)

    Simonoska Crcarevska, Maja; Dimitrovska, Aneta; Sibinovska, Nadica; Mladenovska, Kristina; Slavevska Raicki, Renata; Glavas Dodov, Marija

    2015-07-15

    Microsponges drug delivery system (MDDC) was prepared by double emulsion-solvent-diffusion technique using rotor-stator homogenization. Quality by design (QbD) concept was implemented for the development of MDDC with potential to be incorporated into semisolid dosage form (gel). Quality target product profile (QTPP) and critical quality attributes (CQA) were defined and identified, accordingly. Critical material attributes (CMA) and Critical process parameters (CPP) were identified using quality risk management (QRM) tool, failure mode, effects and criticality analysis (FMECA). CMA and CPP were identified based on results obtained from principal component analysis (PCA-X&Y) and partial least squares (PLS) statistical analysis along with literature data, product and process knowledge and understanding. FMECA identified amount of ethylcellulose, chitosan, acetone, dichloromethane, span 80, tween 80 and water ratio in primary/multiple emulsions as CMA and rotation speed and stirrer type used for organic solvent removal as CPP. The relationship between identified CPP and particle size as CQA was described in the design space using design of experiments - one-factor response surface method. Obtained results from statistically designed experiments enabled establishment of mathematical models and equations that were used for detailed characterization of influence of identified CPP upon MDDC particle size and particle size distribution and their subsequent optimization. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Optimization of the production of biodiesel by a commercial immobilized lipase in a solvent-free system using a response surface methodology

    Directory of Open Access Journals (Sweden)

    ZORICA KNEZEVIC

    2008-02-01

    Full Text Available Response surface methodology was used for the evaluation of the effects of various factors on the synthesis of biodiesel catalyzed with immobilized lipase from Rhizomucor miehei in a solvent-free system. The production of biodiesel was optimized and model response equations were obtained, enabling the prediction of biodiesel production from the values of the four main factors. It would seem that the reaction temperature and the amount of water predominantly determined the conversion process while the methanol/oil molar ratio had no significant influence on the reaction rate. The temperature and amount of water showed negative interactive effects on the observed reaction rate per amount of enzyme. However, there were no significant interactions among the other variables according to the test of statistical significance. The highest yield of 10.15 mol kg-1 enzyme was observed at 45 °C with a 6:1 methanol to oil molar ratio and with no added water in the system.

  7. The SWAN-SCALE code for the optimization of critical systems

    International Nuclear Information System (INIS)

    Greenspan, E.; Karni, Y.; Regev, D.; Petrie, L.M.

    1999-01-01

    The SWAN optimization code was recently developed to identify the maximum value of k eff for a given mass of fissile material when in combination with other specified materials. The optimization process is iterative; in each iteration SWAN varies the zone-dependent concentration of the system constituents. This change is guided by the equal volume replacement effectiveness functions (EVREF) that SWAN generates using first-order perturbation theory. Previously, SWAN did not have provisions to account for the effect of the composition changes on neutron cross-section resonance self-shielding; it used the cross sections corresponding to the initial system composition. In support of the US Department of Energy Nuclear Criticality Safety Program, the authors recently removed the limitation on resonance self-shielding by coupling SWAN with the SCALE code package. The purpose of this paper is to briefly describe the resulting SWAN-SCALE code and to illustrate the effect that neutron cross-section self-shielding could have on the maximum k eff and on the corresponding system composition

  8. Particle swarm optimization-based least squares support vector regression for critical heat flux prediction

    International Nuclear Information System (INIS)

    Jiang, B.T.; Zhao, F.Y.

    2013-01-01

    Highlights: ► CHF data are collected from the published literature. ► Less training data are used to train the LSSVR model. ► PSO is adopted to optimize the key parameters to improve the model precision. ► The reliability of LSSVR is proved through parametric trends analysis. - Abstract: In view of practical importance of critical heat flux (CHF) for design and safety of nuclear reactors, accurate prediction of CHF is of utmost significance. This paper presents a novel approach using least squares support vector regression (LSSVR) and particle swarm optimization (PSO) to predict CHF. Two available published datasets are used to train and test the proposed algorithm, in which PSO is employed to search for the best parameters involved in LSSVR model. The CHF values obtained by the LSSVR model are compared with the corresponding experimental values and those of a previous method, adaptive neuro fuzzy inference system (ANFIS). This comparison is also carried out in the investigation of parametric trends of CHF. It is found that the proposed method can achieve the desired performance and yields a more satisfactory fit with experimental results than ANFIS. Therefore, LSSVR method is likely to be suitable for other parameters processing such as CHF

  9. Combining nutrition and exercise to optimize survival and recovery from critical illness: Conceptual and methodological issues.

    Science.gov (United States)

    Heyland, Daren K; Stapleton, Renee D; Mourtzakis, Marina; Hough, Catherine L; Morris, Peter; Deutz, Nicolaas E; Colantuoni, Elizabeth; Day, Andrew; Prado, Carla M; Needham, Dale M

    2016-10-01

    Survivors of critical illness commonly experience neuromuscular abnormalities, including muscle weakness known as ICU-acquired weakness (ICU-AW). ICU-AW is associated with delayed weaning from mechanical ventilation, extended ICU and hospital stays, more healthcare-related hospital costs, a higher risk of death, and impaired physical functioning and quality of life in the months after ICU admission. These observations speak to the importance of developing new strategies to aid in the physical recovery of acute respiratory failure patients. We posit that to maintain optimal muscle mass, strength and physical function, the combination of nutrition and exercise may have the greatest impact on physical recovery of survivors of critical illness. Randomized trials testing this and related hypotheses are needed. We discussed key methodological issues and proposed a common evaluation framework to stimulate work in this area and standardize our approach to outcome assessments across future studies. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  10. An Optimized WSN Design for Latency-Critical Smart Grid Applications

    Directory of Open Access Journals (Sweden)

    Mounib Khanafer

    2017-01-01

    Full Text Available The growing popularity of the Internet of Things (IoT systems such as the smart grid, Body Area Networks (BANs, and the Intelligent Transportation System (ITS is driving Wireless Sensor Network (WSN systems to the limit in terms of abilities and performance. WSNs were initially designed for low power, low data rate, and latency-tolerant applications. However, this paradigm is changing because of the nature of the new applications. Therefore, instead of only focusing on power-efficient WSN design, researchers and industries are now developing Quality of Service (QoS protocols for WSNs. In addition to that, latency- and reliability-critical protocol designs are also becoming significantly important in WSNs. In this paper, we present an overview of some important smart grid latency-critical applications and highlight WSNs implementation challenges for these smart grid applications. Furthermore, we develop and evaluate two novel optimization models that solve for the optimum values of the end-to-end latency and power consumption in a clustered WSN given lower bounds on reliability and other network parameters.

  11. Optimal task mapping in safety-critical real-time parallel systems

    International Nuclear Information System (INIS)

    Aussagues, Ch.

    1998-01-01

    This PhD thesis is dealing with the correct design of safety-critical real-time parallel systems. Such systems constitutes a fundamental part of high-performance systems for command and control that can be found in the nuclear domain or more generally in parallel embedded systems. The verification of their temporal correctness is the core of this thesis. our contribution is mainly in the following three points: the analysis and extension of a programming model for such real-time parallel systems; the proposal of an original method based on a new operator of synchronized product of state machines task-graphs; the validation of the approach by its implementation and evaluation. The work addresses particularly the main problem of optimal task mapping on a parallel architecture, such that the temporal constraints are globally guaranteed, i.e. the timeliness property is valid. The results incorporate also optimally criteria for the sizing and correct dimensioning of a parallel system, for instance in the number of processing elements. These criteria are connected with operational constraints of the application domain. Our approach is based on the off-line analysis of the feasibility of the deadline-driven dynamic scheduling that is used to schedule tasks inside one processor. This leads us to define the synchronized-product, a system of linear, constraints is automatically generated and then allows to calculate a maximum load of a group of tasks and then to verify their timeliness constraints. The communications, their timeliness verification and incorporation to the mapping problem is the second main contribution of this thesis. FInally, the global solving technique dealing with both task and communication aspects has been implemented and evaluated in the framework of the OASIS project in the LETI research center at the CEA/Saclay. (author)

  12. The Efficacy of a Restart Break for Recycling with Optimal Performance Depends Critically on Circadian Timing

    Science.gov (United States)

    Van Dongen, Hans P.A.; Belenky, Gregory; Vila, Bryan J.

    2011-01-01

    deficits. Conclusions: The 34-hour restart break was adequate for maintaining performance in the case of optimal circadian placement of sleep and duty periods (control condition) but was inadequate (and perhaps even detrimental) for maintaining performance in a simulated nighttime duty schedule (experimental condition). Current US transportation hours-of-service regulations mandate time off duty but do not consider the circadian aspects of shift scheduling. Reinforcing a recent trend of applying sleep science to inform policymaking for duty and rest times, our findings indicate that restart provisions in hours-of-service regulations could be improved by taking the circadian timing of the duty schedules into account. Citation: Van Dongen HPA; Belenky G; Vila BJ. The efficacy of a restart break for recycling with optimal performance depends critically on circadian timing. SLEEP 2011;34(7):917-929. PMID:21731142

  13. A Critical Survey of Optimization Models for Tactical and Strategic Aspects of Air Traffic Flow Management

    Science.gov (United States)

    Bertsimas, Dimitris; Odoni, Amedeo

    1997-01-01

    This document presents a critical review of the principal existing optimization models that have been applied to Air Traffic Flow Management (TFM). Emphasis will be placed on two problems, the Generalized Tactical Flow Management Problem (GTFMP) and the Ground Holding Problem (GHP), as well as on some of their variations. To perform this task, we have carried out an extensive literature review that has covered more than 40 references, most of them very recent. Based on the review of this emerging field our objectives were to: (i) identify the best available models; (ii) describe typical contexts for applications of the models; (iii) provide illustrative model formulations; and (iv) identify the methodologies that can be used to solve the models. We shall begin our presentation below by providing a brief context for the models that we are reviewing. In Section 3 we shall offer a taxonomy and identify four classes of models for review. In Sections 4, 5, and 6 we shall then review, respectively, models for the Single-Airport Ground Holding Problem, the Generalized Tactical FM P and the Multi-Airport Ground Holding Problem (for the definition of these problems see Section 3 below). In each section, we identify the best available models and discuss briefly their computational performance and applications, if any, to date. Section 7 summarizes our conclusions about the state of the art.

  14. Measuring tele-ICU impact: does it optimize quality outcomes for the critically ill patient?

    Science.gov (United States)

    Goran, Susan F

    2012-04-01

    To determine the relationship between tele-ICU (intensive care unit) implementations and improvement in quality measures and patient outcomes. Tele-ICUs were designed to leverage scarce critical-care experts and promised to improve patient quality. Abstracts and peer-reviewed articles were reviewed to identify the associations between tele-ICU programmes and clinical outcomes, cost savings, and customer satisfaction. Few peer-reviewed studies are available and many variables in each study limit the ability to associate study conclusions to the overall tele-ICU programme. Further research is required to explore the impact of the tele-ICU on patient/family satisfaction. Research findings are highly dependent upon the level of ICU acceptance. The tele-ICU, in collaboration with the ICU team, can be a valuable tool for the enhancement of quality goals although the ability to demonstrate cost savings is extremely complex. Studies clearly indicate that tele-ICU nursing vigilance can enhance patient safety by preventing potential patient harm. Nursing managers and leaders play a vital part in optimizing the quality role of the tele-ICU through supportive modelling and the maximization of ICU integration. © 2012 Blackwell Publishing Ltd.

  15. Controlling solution-phase polymer aggregation with molecular weight and solvent additives to optimize polymer-fullerene bulk heterojunction solar cells

    KAUST Repository

    Bartelt, Jonathan A.; Douglas, Jessica D.; Mateker, William R.; El Labban, Abdulrahman; Tassone, Christopher J.; Toney, Michael F.; Fré chet, Jean Mj J; Beaujuge, Pierre; McGehee, Michael D.

    2014-01-01

    The bulk heterojunction (BHJ) solar cell performance of many polymers depends on the polymer molecular weight (M n) and the solvent additive(s) used for solution processing. However, the mechanism that causes these dependencies is not well

  16. Optimization of the Critical Parameters of the Spherical Agglomeration Crystallization Method by the Application of the Quality by Design Approach

    Directory of Open Access Journals (Sweden)

    Orsolya Gyulai

    2018-04-01

    Full Text Available This research work presents the use of the Quality by Design (QbD concept for optimization of the spherical agglomeration crystallization method in the case of the active agent, ambroxol hydrochloride (AMB HCl. AMB HCl spherical crystals were formulated by the spherical agglomeration method, which was applied as an antisolvent technique. Spherical crystals have good flowing properties, which makes the direct compression tableting method applicable. This means that the amount of additives used can be reduced and smaller tablets can be formed. For the risk assessment, LeanQbD Software was used. According to its results, four independent variables (mixing type and time, dT (temperature difference between solvent and antisolvent, and composition (solvent/antisolvent volume ratio and three dependent variables (mean particle size, aspect ratio, and roundness were selected. Based on these, a 2–3 mixed-level factorial design was constructed, crystallization was accomplished, and the results were evaluated using Statistica for Windows 13 program. Product assay was performed and it was revealed that improvements in the mean particle size (from ~13 to ~200 µm, roundness (from ~2.4 to ~1.5, aspect ratio (from ~1.7 to ~1.4, and flow properties were observed while polymorphic transitions were avoided.

  17. Optimization of the Critical Parameters of the Spherical Agglomeration Crystallization Method by the Application of the Quality by Design Approach.

    Science.gov (United States)

    Gyulai, Orsolya; Kovács, Anita; Sovány, Tamás; Csóka, Ildikó; Aigner, Zoltán

    2018-04-20

    This research work presents the use of the Quality by Design (QbD) concept for optimization of the spherical agglomeration crystallization method in the case of the active agent, ambroxol hydrochloride (AMB HCl). AMB HCl spherical crystals were formulated by the spherical agglomeration method, which was applied as an antisolvent technique. Spherical crystals have good flowing properties, which makes the direct compression tableting method applicable. This means that the amount of additives used can be reduced and smaller tablets can be formed. For the risk assessment, LeanQbD Software was used. According to its results, four independent variables (mixing type and time, dT (temperature difference between solvent and antisolvent), and composition (solvent/antisolvent volume ratio)) and three dependent variables (mean particle size, aspect ratio, and roundness) were selected. Based on these, a 2⁻3 mixed-level factorial design was constructed, crystallization was accomplished, and the results were evaluated using Statistica for Windows 13 program. Product assay was performed and it was revealed that improvements in the mean particle size (from ~13 to ~200 µm), roundness (from ~2.4 to ~1.5), aspect ratio (from ~1.7 to ~1.4), and flow properties were observed while polymorphic transitions were avoided.

  18. Optimization of Time-Partitions for Mixed-Criticality Real-Time Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian; Pop, Paul

    2011-01-01

    In this paper we are interested in mixed-criticality embedded real-time applications mapped on distributed heterogeneous architectures. The architecture provides both spatial and temporal partitioning, thus enforcing enough separation for the critical applications. With temporal partitioning, each...

  19. Optimization of the Critical Diameter and Average Path Length of Social Networks

    Directory of Open Access Journals (Sweden)

    Haifeng Du

    2017-01-01

    Full Text Available Optimizing average path length (APL by adding shortcut edges has been widely discussed in connection with social networks, but the relationship between network diameter and APL is generally ignored in the dynamic optimization of APL. In this paper, we analyze this relationship and transform the problem of optimizing APL into the problem of decreasing diameter to 2. We propose a mathematic model based on a memetic algorithm. Experimental results show that our algorithm can efficiently solve this problem as well as optimize APL.

  20. Stabilization of Li Metal Anode in DMSO-Based Electrolytes via Optimization of Salt-Solvent Coordination for Li-O 2 Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bin [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA 99354 USA; Xu, Wu [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA 99354 USA; Yan, Pengfei [Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99354 USA; Kim, Sun Tai [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA 99354 USA; Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798 South Korea; Engelhard, Mark H. [Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99354 USA; Sun, Xiuliang [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99354 USA; Mei, Donghai [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99354 USA; Cho, Jaephil [Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798 South Korea; Wang, Chong-Min [Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99354 USA; Zhang, Ji-Guang [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA 99354 USA

    2017-03-08

    The conventional DMSO-based electrolyte (1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in DMSO) is unstable against the Li metal anode and therefore cannot be used directly in practical Li-O2 batteries. Here, we demonstrate that a highly concentrated electrolyte based on LiTFSI in DMSO (with a molar ratio of 1:3) can greatly improve the stability of the Li metal anode against DMSO and significantly improve the cycling stability of Li-O2 batteries. This highly concentrated electrolyte contains no free DMSO solvent molecules, but only complexes of (TFSI–)a-Li+-(DMSO)b (where a + b = 4), and thus enhances their stability with Li metal anodes. In addition, such salt-solvent complexes have higher Gibbs activation energy barriers than the free DMSO solvent molecules, indicating improved stability of the electrolyte against the attack of superoxide radical anions. Therefore, the stability of this highly concentrated electrolyte at both Li metal anodes and carbon-based air electrodes has been greatly enhanced, resulting in improved cyclic stability of Li-O2 batteries. The fundamental stability of the electrolyte with free-solvent against the chemical and electrochemical reactions can also be used to enhance the stability of other electrochemical systems.

  1. Optimal Concentration of Organic Solvents to be Used in the Broth Microdilution Method to Determine the Antimicrobial Activity of Natural Products Against Paenibacillus Larvae

    Directory of Open Access Journals (Sweden)

    Cugnata Noelia Melina

    2017-06-01

    Full Text Available American Foulbrood (AFB is a bacterial disease, caused by Paenibacillus larvae, that affects honeybees (Apis mellifera. Alternative strategies to control AFB are based on the treatment of the beehives with antimicrobial natural substances such as extracts, essential oils and/or pure compounds from plants, honey by-products, bacteria and moulds. The broth microdilution method is currently one of the most widely used methods to determine the minimum inhibitory concentration (MIC of a substance. In this regard, the fact that most natural products, due to their lipophilic nature, must be dissolved in organic solvents or their aqueous mixtures is an issue of major concern because the organic solvent becomes part of the dilution in the incubation medium, and therefore, can interfere with bacterial viability depending on its nature and concentration. A systematic study was carried out to determine by the broth microdilution method the MIC and the maximum non inhibitory concentration (MNIC against P. larvae of the most common organic solvents used to extract or dissolve natural products, i.e. ethanol, methanol, acetonitrile, n-butanol, dimethylsulfoxide, and acidified hydromethanolic solutions. From the MIC and MNIC for each organic solvent, recommended maximum concentrations in contact with P. larvae were established: DMSO 5% (v/v, acetonitrile 7.5% (v/v, ethanol 7.5% (v/v, methanol 12% (v/v, n-butanol 1% (v/v, and methanol-water-acetic acid (1.25:98.71:0.04, v/v/v.

  2. In-situ transesterification of seeds of invasive Chinese tallow trees (Triadica sebifera L.) in a microwave batch system (GREEN(3)) using hexane as co-solvent: Biodiesel production and process optimization.

    Science.gov (United States)

    Barekati-Goudarzi, Mohamad; Boldor, Dorin; Nde, Divine B

    2016-02-01

    In-situ transesterification (simultaneous extraction and transesterification) of Chinese tallow tree seeds into methyl esters using a batch microwave system was investigated in this study. A high degree of oil extraction and efficient conversion of oil to biodiesel were found in the proposed range. The process was further optimized in terms of product yields and conversion rates using Doehlert optimization methodology. Based on the experimental results and statistical analysis, the optimal production yield conditions for this process were determined as: catalyst concentration of 1.74wt.%, solvent ratio about 3 (v/w), reaction time of 20min and temperature of 58.1°C. H(+)NMR was used to calculate reaction conversion. All methyl esters produced using this method met ASTM biodiesel quality specifications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Critical systematic evaluation and thermodynamic optimization of the Mn–RE system: RE = La, Ce, Pr, Nd and Sm

    International Nuclear Information System (INIS)

    Kim, Junghwan; Jung, In-Ho

    2012-01-01

    Highlights: ► The Mn–RE (RE = La, Ce, Pr, Nd and Sm) systems have been critically reviewed. ► The thermodynamic optimization of the Mn–RE systems have been performed. ► Systematic changes in the phase diagrams and thermodynamic properties were found. ► The systematic approach resolved inconsistencies in the experimental data. - Abstract: Critical evaluation and optimization of all available phase diagram and thermodynamic data for the Mn–RE (RE = La, Ce, Pr, Nd and Sm) systems have been conducted to obtain reliable thermodynamic functions of all the phases in the system. In the thermodynamic modeling, it is found that the Mn–RE systems show systematic changes in the phase diagrams and thermodynamic properties such as enthalpy of mixing in liquid state in the order of periodic number in the lanthanide series. This systematic thermodynamic modeling approach for all light RE elements can allow to resolve inconsistencies in the experimental data.

  4. Evaluation of the Hydraulic Performance and Mass Transfer Efficiency of the CSSX Process with the Optimized Solvent in a Single Stage of 5.5-Cm Diameter Centrifugal Contactor

    International Nuclear Information System (INIS)

    Law, J.D.; Tillotson, R.D.; Todd, T.A.

    2002-01-01

    The Caustic-Side Solvent Extraction (CSSX) process has been selected for the separation of cesium from Savannah River Site high-level waste. The solvent composition used in the CSSX process was recently optimized so that the solvent is no longer supersaturated with respect to the calixarene crown ether extractant. Hydraulic performance and mass transfer efficiency testing of a single stage of 5.5-cm ORNL-designed centrifugal contactor has been performed for the CSSX process with the optimized solvent. Maximum throughputs of the 5.5-cm centrifugal contactor, as a function of contactor rotor speed, have been measured for the extraction, scrub, strip, and wash sections of the CSSX flowsheet at the baseline organic/aqueous flow ratios (O/A) of the process, as well as at O/A's 20% higher and 20% lower than the baseline. Maximum throughputs are comparable to the design throughput of the contactor, as well as with throughputs obtained previously in a 5-cm centrifugal contactor with the non-optimized CSSX solvent formulation. The 20% variation in O/A had minimal effect on contactor throughput. Additionally, mass transfer efficiencies have been determined for the extraction and strip sections of the flowsheet. Efficiencies were lower than the process goal of greater than or equal to 80%, ranging from 72 to 75% for the extraction section and from 36 to 60% in the strip section. Increasing the mixing intensity and/or the solution level in the mixing zone of the centrifugal contactor (residence time) could potentially increase efficiencies. Several methods are available to accomplish this including (1) increasing the size of the opening in the bottom of the rotor, resulting in a contactor which is partially pumping instead of fully pumping, (2) decreasing the number of vanes in the contactor, (3) increasing the vane height, or (4) adding vanes on the rotor and baffles on the housing of the contactor. The low efficiency results obtained stress the importance of proper design of

  5. Optimization of the fuel assembly for the Canadian SuperCritical Water-cooled Reactor (SCWR)

    Energy Technology Data Exchange (ETDEWEB)

    French, C., E-mail: Corey.French@cnsc-ccsn.gc.ca [Canadian Nuclear Safety Commission, Ottawa, Ontario (Canada); Bonin, H.; Chan, P.K. [Royal Military College of Ontario, Kingston, Ontario (Canada)

    2013-07-01

    An approach to develop a parametric optimization tool to support the Canadian Supercritical Water-cooled Reactor (SCWR) fuel design is presented in this work. The 2D benchmark lattices for 78-pin and 64-pin fuel assemblies are used as the initial models from which fuel performance and subsequent optimization stem from. A tandem optimization procedure is integrated which employs the steepest descent method. The physics codes WIMS-AECL, MCNP6 and SERPENT are used to calculate and verify select performance factors. The results are used as inputs to an optimization algorithm that yield optimal fresh fuel isotopic composition and lattice geometry. Preliminary results on verifications of infinite lattice reactivity are demonstrated in this paper. (author)

  6. Optimal and robust control of a class of nonlinear systems using dynamically re-optimised single network adaptive critic design

    Science.gov (United States)

    Tiwari, Shivendra N.; Padhi, Radhakant

    2018-01-01

    Following the philosophy of adaptive optimal control, a neural network-based state feedback optimal control synthesis approach is presented in this paper. First, accounting for a nominal system model, a single network adaptive critic (SNAC) based multi-layered neural network (called as NN1) is synthesised offline. However, another linear-in-weight neural network (called as NN2) is trained online and augmented to NN1 in such a manner that their combined output represent the desired optimal costate for the actual plant. To do this, the nominal model needs to be updated online to adapt to the actual plant, which is done by synthesising yet another linear-in-weight neural network (called as NN3) online. Training of NN3 is done by utilising the error information between the nominal and actual states and carrying out the necessary Lyapunov stability analysis using a Sobolev norm based Lyapunov function. This helps in training NN2 successfully to capture the required optimal relationship. The overall architecture is named as 'Dynamically Re-optimised single network adaptive critic (DR-SNAC)'. Numerical results for two motivating illustrative problems are presented, including comparison studies with closed form solution for one problem, which clearly demonstrate the effectiveness and benefit of the proposed approach.

  7. Organic solvent-free air-assisted liquid-liquid microextraction for optimized extraction of illegal azo-based dyes and their main metabolite from spices, cosmetics and human bio-fluid samples in one step.

    Science.gov (United States)

    Barfi, Behruz; Asghari, Alireza; Rajabi, Maryam; Sabzalian, Sedigheh

    2015-08-15

    Air-assisted liquid-liquid microextraction (AALLME) has unique capabilities to develop as an organic solvent-free and one-step microextraction method, applying ionic-liquids as extraction solvent and avoiding centrifugation step. Herein, a novel and simple eco-friendly method, termed one-step air-assisted liquid-liquid microextraction (OS-AALLME), was developed to extract some illegal azo-based dyes (including Sudan I to IV, and Orange G) from food and cosmetic products. A series of experiments were investigated to achieve the most favorable conditions (including extraction solvent: 77μL of 1-Hexyl-3-methylimidazolium hexafluorophosphate; sample pH 6.3, without salt addition; and extraction cycles: 25 during 100s of sonication) using a central composite design strategy. Under these conditions, limits of detection, linear dynamic ranges, enrichment factors and consumptive indices were in the range of 3.9-84.8ngmL(-1), 0.013-3.1μgmL(-1), 33-39, and 0.13-0.15, respectively. The results showed that -as well as its simplicity, fastness, and use of no hazardous disperser and extraction solvents- OS-AALLME is an enough sensitive and efficient method for the extraction of these dyes from complex matrices. After optimization and validation, OS-AALLME was applied to estimate the concentration of 1-amino-2-naphthol in human bio-fluids as a main reductive metabolite of selected dyes. Levels of 1-amino-2-naphthol in plasma and urinary excretion suggested that this compound may be used as a new potential biomarker of these dyes in human body. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Critical solvent thermodynamic effect on molecular recognition: The case of the complex formation of carboxylates and ammonium-squaramido based receptors

    Energy Technology Data Exchange (ETDEWEB)

    Piña, M. Nieves, E-mail: neus.pinya@uib.es; López, Kenia A.; Costa, Antoni; Morey, Jeroni, E-mail: jeroni.morey@uib.es

    2013-10-10

    Graphical abstract: - Highlights: • The enthalpy–entropy compensation in the complex is independent of the spacer used. • The enthalpy–entropy compensation is dependent on the microscopic nature of the binary mixture. • The enthalpy–entropy compensation is dependent on the proportion of the components of the binary mixture. - Abstract: An isothermal titration microcalorimetry (ITC) study on the supramolecular complex formation between carboxylates and ammonium-squaramido based receptors at different ethanol:water proportions is reported. The results obtained show that the formation enthalpy sign of a supramolecular complex in a water–ethanol binary mixture can be influenced by the proportion of the cosolvent. Moreover there is an enthalpy–entropy compensation process in the supramolecular complex formation; in poor water mixtures the process is endothermic, whilst in reach water mixtures the process is exothermic. This behavior is mostly due to the intrinsic nature of the mixture between water and ethanol, and particularly the process of solvation and desolvation of receptor, substrate and complex. When this study is repeated with binary mixtures of water–methanol and water–DMSO it is observed that the nature of the organic solvent affects the results. While the mixture water–methanol has a behavior similar to water–ethanol mixture, the water–DMSO mixture shows clear differences. In order to check this compensation process, △Cp values are calculated at two different proportions water–ethanol, and they are consistent with an enthalpy–entropy compensation process similar to that described by the inclusion process for certain hydrophilic cyclodextrines. The results obtained show that the enthalpy–entropy compensation detected in the supramolecular complex formation between carboxylates and ammonium-squaramido receptors is independent of the spacer used, and more dependent on the microscopic nature and proportion of the binary mixture.

  9. Critical solvent thermodynamic effect on molecular recognition: The case of the complex formation of carboxylates and ammonium-squaramido based receptors

    International Nuclear Information System (INIS)

    Piña, M. Nieves; López, Kenia A.; Costa, Antoni; Morey, Jeroni

    2013-01-01

    Graphical abstract: - Highlights: • The enthalpy–entropy compensation in the complex is independent of the spacer used. • The enthalpy–entropy compensation is dependent on the microscopic nature of the binary mixture. • The enthalpy–entropy compensation is dependent on the proportion of the components of the binary mixture. - Abstract: An isothermal titration microcalorimetry (ITC) study on the supramolecular complex formation between carboxylates and ammonium-squaramido based receptors at different ethanol:water proportions is reported. The results obtained show that the formation enthalpy sign of a supramolecular complex in a water–ethanol binary mixture can be influenced by the proportion of the cosolvent. Moreover there is an enthalpy–entropy compensation process in the supramolecular complex formation; in poor water mixtures the process is endothermic, whilst in reach water mixtures the process is exothermic. This behavior is mostly due to the intrinsic nature of the mixture between water and ethanol, and particularly the process of solvation and desolvation of receptor, substrate and complex. When this study is repeated with binary mixtures of water–methanol and water–DMSO it is observed that the nature of the organic solvent affects the results. While the mixture water–methanol has a behavior similar to water–ethanol mixture, the water–DMSO mixture shows clear differences. In order to check this compensation process, △Cp values are calculated at two different proportions water–ethanol, and they are consistent with an enthalpy–entropy compensation process similar to that described by the inclusion process for certain hydrophilic cyclodextrines. The results obtained show that the enthalpy–entropy compensation detected in the supramolecular complex formation between carboxylates and ammonium-squaramido receptors is independent of the spacer used, and more dependent on the microscopic nature and proportion of the binary mixture

  10. Process for hydrogenating coal and coal solvents

    Energy Technology Data Exchange (ETDEWEB)

    Shridharani, K.G.; Tarrer, A.R.

    1983-02-15

    A novel process is described for the hydrogenation of coal by the hydrogenation of a solvent for the coal in which the hydrogenation of the coal solvent is conducted in the presence of a solvent hydrogenation catalyst of increased activity, wherein the hydrogenation catalyst is produced by reacting ferric oxide with hydrogen sulfide at a temperature range of 260/sup 0/ C to 315/sup 0/ C in an inert atmosphere to produce an iron sulfide hydrogenation catalyst for the solvent. Optimally, the reaction temperature is 275/sup 0/ C. Alternately, the reaction can be conducted in a hydrogen atmosphere at 350/sup 0/ C.

  11. Process for hydrogenating coal and coal solvents

    Science.gov (United States)

    Tarrer, Arthur R.; Shridharani, Ketan G.

    1983-01-01

    A novel process is described for the hydrogenation of coal by the hydrogenation of a solvent for the coal in which the hydrogenation of the coal solvent is conducted in the presence of a solvent hydrogenation catalyst of increased activity, wherein the hydrogenation catalyst is produced by reacting ferric oxide with hydrogen sulfide at a temperature range of 260.degree. C. to 315.degree. C. in an inert atmosphere to produce an iron sulfide hydrogenation catalyst for the solvent. Optimally, the reaction temperature is 275.degree. C. Alternately, the reaction can be conducted in a hydrogen atmosphere at 350.degree. C.

  12. Two-Phase Iteration for Value Function Approximation and Hyperparameter Optimization in Gaussian-Kernel-Based Adaptive Critic Design

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2015-01-01

    Full Text Available Adaptive Dynamic Programming (ADP with critic-actor architecture is an effective way to perform online learning control. To avoid the subjectivity in the design of a neural network that serves as a critic network, kernel-based adaptive critic design (ACD was developed recently. There are two essential issues for a static kernel-based model: how to determine proper hyperparameters in advance and how to select right samples to describe the value function. They all rely on the assessment of sample values. Based on the theoretical analysis, this paper presents a two-phase simultaneous learning method for a Gaussian-kernel-based critic network. It is able to estimate the values of samples without infinitively revisiting them. And the hyperparameters of the kernel model are optimized simultaneously. Based on the estimated sample values, the sample set can be refined by adding alternatives or deleting redundances. Combining this critic design with actor network, we present a Gaussian-kernel-based Adaptive Dynamic Programming (GK-ADP approach. Simulations are used to verify its feasibility, particularly the necessity of two-phase learning, the convergence characteristics, and the improvement of the system performance by using a varying sample set.

  13. A single network adaptive critic (SNAC) architecture for optimal control synthesis for a class of nonlinear systems.

    Science.gov (United States)

    Padhi, Radhakant; Unnikrishnan, Nishant; Wang, Xiaohua; Balakrishnan, S N

    2006-12-01

    Even though dynamic programming offers an optimal control solution in a state feedback form, the method is overwhelmed by computational and storage requirements. Approximate dynamic programming implemented with an Adaptive Critic (AC) neural network structure has evolved as a powerful alternative technique that obviates the need for excessive computations and storage requirements in solving optimal control problems. In this paper, an improvement to the AC architecture, called the "Single Network Adaptive Critic (SNAC)" is presented. This approach is applicable to a wide class of nonlinear systems where the optimal control (stationary) equation can be explicitly expressed in terms of the state and costate variables. The selection of this terminology is guided by the fact that it eliminates the use of one neural network (namely the action network) that is part of a typical dual network AC setup. As a consequence, the SNAC architecture offers three potential advantages: a simpler architecture, lesser computational load and elimination of the approximation error associated with the eliminated network. In order to demonstrate these benefits and the control synthesis technique using SNAC, two problems have been solved with the AC and SNAC approaches and their computational performances are compared. One of these problems is a real-life Micro-Electro-Mechanical-system (MEMS) problem, which demonstrates that the SNAC technique is applicable to complex engineering systems.

  14. Clinical review: optimizing enteral nutrition for critically ill patients - a simple data-driven formula

    Science.gov (United States)

    2011-01-01

    In modern critical care, the paradigm of 'therapeutic nutrition' is replacing traditional 'supportive nutrition'. Standard enteral formulas meet basic macro- and micronutrient needs; therapeutic enteral formulas meet these basic needs and also contain specific pharmaconutrients that may attenuate hyperinflammatory responses, enhance the immune responses to infection, or improve gastrointestinal tolerance. Choosing the right enteral feeding formula may positively affect a patient's outcome; targeted use of therapeutic formulas can reduce the incidence of infectious complications, shorten lengths of stay in the ICU and in the hospital, and lower risk for mortality. In this paper, we review principles of how to feed (enteral, parenteral, or both) and when to feed (early versus delayed start) patients who are critically ill. We discuss what to feed these patients in the context of specific pharmaconutrients in specialized feeding formulations, that is, arginine, glutamine, antioxidants, certain ω-3 and ω-6 fatty acids, hydrolyzed proteins, and medium-chain triglycerides. We summarize current expert guidelines for nutrition in patients with critical illness, and we present specific clinical evidence on the use of enteral formulas supplemented with anti-inflammatory or immune-modulating nutrients, and gastrointestinal tolerance-promoting nutritional formulas. Finally, we introduce an algorithm to help bedside clinicians make data-driven feeding decisions for patients with critical illness. PMID:22136305

  15. Optimizing mission critical data dissemination in massive IoT networks

    KAUST Repository

    Farooq, Muhammad Junaid; Elsawy, Hesham; Zhu, Quanyan; Alouini, Mohamed-Slim

    2017-01-01

    Mission critical data dissemination in massive Internet of things (IoT) networks imposes constraints on the message transfer delay between devices. Due to low power and communication range of IoT devices, data is foreseen to be relayed over multiple

  16. Controlling solution-phase polymer aggregation with molecular weight and solvent additives to optimize polymer-fullerene bulk heterojunction solar cells

    KAUST Repository

    Bartelt, Jonathan A.

    2014-03-20

    The bulk heterojunction (BHJ) solar cell performance of many polymers depends on the polymer molecular weight (M n) and the solvent additive(s) used for solution processing. However, the mechanism that causes these dependencies is not well understood. This work determines how M n and solvent additives affect the performance of BHJ solar cells made with the polymer poly(di(2-ethylhexyloxy)benzo[1,2-b:4,5-b\\']dithiophene-co- octylthieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD). Low M n PBDTTPD devices have exceedingly large fullerene-rich domains, which cause extensive charge-carrier recombination. Increasing the M n of PBDTTPD decreases the size of these domains and significantly improves device performance. PBDTTPD aggregation in solution affects the size of the fullerene-rich domains and this effect is linked to the dependency of PBDTTPD solubility on M n. Due to its poor solubility high M n PBDTTPD quickly forms a fibrillar polymer network during spin-casting and this network acts as a template that prevents large-scale phase separation. Furthermore, processing low M n PBDTTPD devices with a solvent additive improves device performance by inducing polymer aggregation in solution and preventing large fullerene-rich domains from forming. These findings highlight that polymer aggregation in solution plays a significant role in determining the morphology and performance of BHJ solar cells. The performance of poly(di(2-ethylhexyloxy) benzo[1,2-b:4,5-b\\']dithiophene-co-octylthieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) bulk heterojunction solar cells strongly depends on the polymer molecular weight, and processing these bulk heterojunctions with a solvent additive preferentially improves the performance of low molecular weight devices. It is demonstrated that polymer aggregation in solution significantly impacts the thin-film bulk heterojunction morphology and is vital for high device performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Analysis on optimization of the critical path for civil construction period of Fangjiashan nuclear island constructed under EPC mode

    International Nuclear Information System (INIS)

    Liu Yongqing; Wu Youcong; Qiu Jinhong

    2011-01-01

    Based on the actual situation of nuclear island civil construction in Fangjiashan nuclear power plant and combined with the arrangement of the construction schedule, the analysis on optimization of the critical path for civil construction period is conducted. The result shows that on the premise of not increasing the contract price and the total engineering cost based on the original 57-month construction period, the construction period can be shorten to 21 month through strengthening the schedule control, keeping the critical work in a reasonable duration and rearranging the link between programmers. In addition, in view of the economic analysis, if we increase the mechanical engagement and adopt special method, the 2-month construction period can be even shortened to 20 months. (authors)

  18. New technology for optimized I and C maintenance and management of ageing of critical equipment in nuclear power plants

    International Nuclear Information System (INIS)

    Hashemian, H.M.

    2000-01-01

    Advanced sensors and new testing and maintenance technologies have become available over the last ten years for nuclear power plants (NPPs) to replace outdated, obsolete, and troublesome instruments, provide for management of ageing of critical plant equipment, optimize maintenance activities, reduce maintenance costs and personnel radiation exposure, and at the same time, improve plant safety and availability. These new developments are reviewed in this TECDOC. The material covered here has been summarized from NUREG/CR-5501, a 1998 report written by H.M. Hashemian and his co-authors for the US Nuclear Regulatory Commission. (author)

  19. Use of Monte Carlo Simulations to Determine Optimal Carbapenem Dosing in Critically Ill Patients Receiving Prolonged Intermittent Renal Replacement Therapy.

    Science.gov (United States)

    Lewis, Susan J; Kays, Michael B; Mueller, Bruce A

    2016-10-01

    Pharmacokinetic/pharmacodynamic analyses with Monte Carlo simulations (MCSs) can be used to integrate prior information on model parameters into a new renal replacement therapy (RRT) to develop optimal drug dosing when pharmacokinetic trials are not feasible. This study used MCSs to determine initial doripenem, imipenem, meropenem, and ertapenem dosing regimens for critically ill patients receiving prolonged intermittent RRT (PIRRT). Published body weights and pharmacokinetic parameter estimates (nonrenal clearance, free fraction, volume of distribution, extraction coefficients) with variability were used to develop a pharmacokinetic model. MCS of 5000 patients evaluated multiple regimens in 4 different PIRRT effluent/duration combinations (4 L/h × 10 hours or 5 L/h × 8 hours in hemodialysis or hemofiltration) occurring at the beginning or 14-16 hours after drug infusion. The probability of target attainment (PTA) was calculated using ≥40% free serum concentrations above 4 times the minimum inhibitory concentration (MIC) for the first 48 hours. Optimal doses were defined as the smallest daily dose achieving ≥90% PTA in all PIRRT combinations. At the MIC of 2 mg/L for Pseudomonas aeruginosa, optimal doses were doripenem 750 mg every 8 hours, imipenem 1 g every 8 hours or 750 mg every 6 hours, and meropenem 1 g every 12 hours or 1 g pre- and post-PIRRT. Ertapenem 500 mg followed by 500 mg post-PIRRT was optimal at the MIC of 1 mg/L for Streptococcus pneumoniae. Incorporating data from critically ill patients receiving RRT into MCS resulted in markedly different carbapenem dosing regimens in PIRRT from those recommended for conventional RRTs because of the unique drug clearance characteristics of PIRRT. These results warrant clinical validation. © 2016, The American College of Clinical Pharmacology.

  20. Critical path method as the criterion for optimization of business planning process

    OpenAIRE

    Butsenko Elena V.

    2016-01-01

    In today's economy the task of improving business planning is considered a necessary component of any enterprise management process and is precisely the solution drawn from that task which determines the financial policy and economic structure. The development of technologies based on the optimization of business planning is a very urgent scientific challenge. In this paper we propose to use the methods of network planning and management as a tool for economic and mathematical modeling to...

  1. Maintenance cost optimization in condition based maintenance: a case study for critical facilities

    OpenAIRE

    Filippo De Carlo; Maria Antonietta Arleo

    2013-01-01

    The increasing availability required to industrial plants and the limited budget often existing to assure it, require a careful formulation of maintenance optimization models. This need is primary for process plants, for which minimization of stops and maximization of their availability, are essential for ensuring targeted production and, therefore, profitability. In this context, the choice of the maintenance strategy is hence fundamental, depending on the system features and then on the eff...

  2. Hardware Genetic Algorithm Optimization by Critical Path Analysis using a Custom VLSI Architecture

    Directory of Open Access Journals (Sweden)

    Farouk Smith

    2015-07-01

    Full Text Available This paper propose a Virtual-Field Programmable Gate Array (V-FPGA architecture that allows direct access to its configuration bits to facilitate hardware evolution, thereby allowing any combinational or sequential digital circuit to be realized. By using the V-FPGA, this paper investigates two possible ways of making evolutionary hardware systems more scalable: by optimizing the system’s genetic algorithm (GA; and by decomposing the solution circuit into smaller, evolvable sub-circuits. GA optimization is done by: omitting a canonical GA’s crossover operator (i.e. by using a 1+λ algorithm; applying evolution constraints; and optimizing the fitness function. A noteworthy contribution this research has made is the in-depth analysis of the phenotypes’ CPs. Through analyzing the CPs, it has been shown that a great amount of insight can be gained into a phenotype’s fitness. We found that as the number of columns in the Cartesian Genetic Programming array increases, so the likelihood of an external output being placed in the column decreases. Furthermore, the number of used LEs per column also substantially decreases per added column. Finally, we demonstrated the evolution of a state-decomposed control circuit. It was shown that the evolution of each state’s sub-circuit was possible, and suggest that modular evolution can be a successful tool when dealing with scalability.

  3. Right dose, right now: using big data to optimize antibiotic dosing in the critically ill.

    Science.gov (United States)

    Elbers, Paul W G; Girbes, Armand; Malbrain, Manu L N G; Bosman, Rob

    2015-01-01

    Antibiotics save lives and are essential for the practice of intensive care medicine. Adequate antibiotic treatment is closely related to outcome. However this is challenging in the critically ill, as their pharmacokinetic profile is markedly altered. Therefore, it is surprising that critical care physicians continue to rely on standard dosing regimens for every patient, regardless of the actual clinical situation. This review outlines the pharmacokinetic and pharmacodynamic principles that underlie the need for individualized and personalized drug dosing. At present, therapeutic drug monitoring may be of help, but has major disadvantages, remains unavailable for most antibiotics and has produced mixed results. We therefore propose the AutoKinetics concept, taking decision support for antibiotic dosing back to the bedside. By direct interaction with electronic patient records, this opens the way for the use of big data for providing the right dose at the right time in each patient.

  4. Optimal system size for complex dynamics in random neural networks near criticality

    Energy Technology Data Exchange (ETDEWEB)

    Wainrib, Gilles, E-mail: wainrib@math.univ-paris13.fr [Laboratoire Analyse Géométrie et Applications, Université Paris XIII, Villetaneuse (France); García del Molino, Luis Carlos, E-mail: garciadelmolino@ijm.univ-paris-diderot.fr [Institute Jacques Monod, Université Paris VII, Paris (France)

    2013-12-15

    In this article, we consider a model of dynamical agents coupled through a random connectivity matrix, as introduced by Sompolinsky et al. [Phys. Rev. Lett. 61(3), 259–262 (1988)] in the context of random neural networks. When system size is infinite, it is known that increasing the disorder parameter induces a phase transition leading to chaotic dynamics. We observe and investigate here a novel phenomenon in the sub-critical regime for finite size systems: the probability of observing complex dynamics is maximal for an intermediate system size when the disorder is close enough to criticality. We give a more general explanation of this type of system size resonance in the framework of extreme values theory for eigenvalues of random matrices.

  5. Optimal system size for complex dynamics in random neural networks near criticality

    International Nuclear Information System (INIS)

    Wainrib, Gilles; García del Molino, Luis Carlos

    2013-01-01

    In this article, we consider a model of dynamical agents coupled through a random connectivity matrix, as introduced by Sompolinsky et al. [Phys. Rev. Lett. 61(3), 259–262 (1988)] in the context of random neural networks. When system size is infinite, it is known that increasing the disorder parameter induces a phase transition leading to chaotic dynamics. We observe and investigate here a novel phenomenon in the sub-critical regime for finite size systems: the probability of observing complex dynamics is maximal for an intermediate system size when the disorder is close enough to criticality. We give a more general explanation of this type of system size resonance in the framework of extreme values theory for eigenvalues of random matrices

  6. Correction of compressor critical speed condition through fluid-film bearing optimization

    International Nuclear Information System (INIS)

    Spencer, J.W.; Obeid, V.E.

    1985-01-01

    A critical speed condition for an overhung centrifugal compressor was corrected through a relatively minor bearing modification. The resonant condition was evaluated analytically through rotor dynamic analyses (stability and forced response) which included fluid film bearing characterization and rotor model generation (experimentally evaluated by model analysis). The importance of adequate specification, inspection, and analytical characterization, of fluid film bearings are discussed. The effects of unbalance on the stability of plain journal bearings are also commented upon. 1 ref., 6 figs

  7. Optimal Braking Patterns and Forces in Autonomous Safety-Critical Maneuvers

    OpenAIRE

    Fors, Victor

    2018-01-01

    The trend of more advanced driver-assistance features and the development toward autonomous vehicles enable new possibilities in the area of active safety. With more information available in the vehicle about the surrounding traffic and the road ahead, there is the possibility of improved active-safety systems that make use of this information for stability control in safety-critical maneuvers. Such a system could adaptively make a trade-off between controlling the longitudinal, lateral, and ...

  8. Strategies for the optimal timing to start renal replacement therapy in critically ill patients with acute kidney injury.

    Science.gov (United States)

    Bagshaw, Sean M; Wald, Ron

    2017-05-01

    Renal replacement therapy (RRT) is increasingly utilized to support critically ill patients with severe acute kidney injury (AKI). The question of whether and when to start RRT for a critically ill patient with AKI has long troubled clinicians. When severe complications of AKI develop, the need to commence RRT is unambiguous. In the absence of such complications but in the presence of severe AKI, the optimal time and thresholds for starting RRT are uncertain. The majority of existing data have largely been derived from observational studies. These have been limited due to confounding by indication, considerable heterogeneity in case mix and illness severity, and variably applied definitions for both AKI and for how "timing" was anchored relative to starting RRT. It is unclear whether a preemptive or earlier strategy of RRT initiation aimed largely at avoiding complications related to AKI or a more conservative strategy where RRT is started in response to developing complications leads to better patient-centered outcomes and health services use. This question has been the focus of 2 recently completed randomized trials. In this review, we provide an appraisal of available evidence, discuss existing knowledge gaps, and provide perspective on future research that will better inform the optimal timing of RRT initiation in AKI. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  9. Solvents and solvent effects in organic chemistry

    National Research Council Canada - National Science Library

    Reichardt, C; Welton, T

    2011-01-01

    .../guest complexation equilibria and reactions in biphasic solvent systems and neoteric solvents, respectively. More than 900 new references have been added, giving preference to review articles, and many older ones have been deleted. New references either replace older ones or are added to the end of the respective reference list of each chapter. Th...

  10. Design Optimization of Mixed-Criticality Real-Time Embedded Systems

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian; Pop, Paul

    2015-01-01

    is allocated several time slots on a processor. Tasks of different SILs can share a partition only if they are all elevated to the highest SIL among them. Such elevation leads to increased development costs, which increase dramatically with each SIL. Tasks of higher SILs can be decomposed into redundant...... structures of lower SIL tasks. We are interested to determine (i) the mapping of tasks to processors, (ii) the assignment of tasks to partitions, (iii) the decomposition of tasks into redundant lower SIL tasks, (iv) the sequence and size of the partition time slots on each processor, and (v) the schedule...... tables, such that all the applications are schedulable and the development costs are minimized. We have proposed a Tabu Search-based approach to solve this optimization problem. The proposed algorithm has been evaluated using several synthetic and real-life benchmarks....

  11. Organic Solvent Tropical Report

    International Nuclear Information System (INIS)

    COWLEY, W.L.

    2000-01-01

    This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an unmitigated organic solvent fire is within risk evaluation guidelines

  12. Canyon solvent cleaning

    International Nuclear Information System (INIS)

    Reif, D.J.

    1986-01-01

    The HM Process at the Savannah River Plant (SRP) uses 7.5% tributylphosphate in n-paraffin as an extraction solvent. During use, the solvent is altered due to hydrolysis and radiolysis, forming materials that influence product losses, produce decontamination, and separation efficiencies. Laboratory studies to improve online solvent cleaning have shown the carbonate washing, although removing residual solvent activity does not remove binding ligands that hold fission products in the solvent. Treatment of solvent by an alumina adsorption process removes binding ligands and significantly improves recycle solvent performance. Both laboratory work defining a full-scale alumina adsorption process and the use of the process to clean HM Process first cycle solvent are presented

  13. Solvent wash solution

    International Nuclear Information System (INIS)

    Neace, J.C.

    1986-01-01

    This patent describes a process for removing diluent degradation products from a solvent extraction solution comprising an admixture of an organic extractant for uranium and plutonium and a non-polar organic liquid diluent, which has been used to recover uranium and plutonium from spent nuclear fuel. Comprising combining a wash solution consisting of: (a) water; and (b) a positive amount up to about, an including, 50 volume percent of at least one highly-polar water-miscible organic solvent, based on the total volume of the water and the highly-polar organic solvent, with the solvent extraction solution after uranium and plutonium values have been stripped from the solvent extraction solution, the diluent degradation products dissolving in the highly-polar organic solvent and the extractant and diluent of the extraction solution not dissolving in the highly-polar organic solvent, and separating the highly-polar organic solvent and the extraction solution to obtain a purified extraction solution

  14. Conventional and accelerated-solvent extractions of green tea (camellia sinensis) for metabolomics-based chemometrics.

    Science.gov (United States)

    Kellogg, Joshua J; Wallace, Emily D; Graf, Tyler N; Oberlies, Nicholas H; Cech, Nadja B

    2017-10-25

    Metabolomics has emerged as an important analytical technique for multiple applications. The value of information obtained from metabolomics analysis depends on the degree to which the entire metabolome is present and the reliability of sample treatment to ensure reproducibility across the study. The purpose of this study was to compare methods of preparing complex botanical extract samples prior to metabolomics profiling. Two extraction methodologies, accelerated solvent extraction and a conventional solvent maceration, were compared using commercial green tea [Camellia sinensis (L.) Kuntze (Theaceae)] products as a test case. The accelerated solvent protocol was first evaluated to ascertain critical factors influencing extraction using a D-optimal experimental design study. The accelerated solvent and conventional extraction methods yielded similar metabolite profiles for the green tea samples studied. The accelerated solvent extraction yielded higher total amounts of extracted catechins, was more reproducible, and required less active bench time to prepare the samples. This study demonstrates the effectiveness of accelerated solvent as an efficient methodology for metabolomics studies. Copyright © 2017. Published by Elsevier B.V.

  15. A pH and solvent optimized reverse-phase ion-paring-LC–MS/MS method that leverages multiple scan-types for targeted absolute quantification of intracellular metabolites

    DEFF Research Database (Denmark)

    McCloskey, Douglas; Gangoiti, Jon A.; Palsson, Bernhard O.

    2015-01-01

    Comprehensive knowledge of intracellular biochemistry is needed to accurately understand, model, and manipulate metabolism for industrial and therapeutic applications. Quantitative metabolomics has been driven by advances in analytical instrumentation and can add valuable knowledge to the underst......Comprehensive knowledge of intracellular biochemistry is needed to accurately understand, model, and manipulate metabolism for industrial and therapeutic applications. Quantitative metabolomics has been driven by advances in analytical instrumentation and can add valuable knowledge...... existing reverse phase ion-paring liquid chromatography methods for separation and detection of polar and anionic compounds that comprise key nodes of intracellular metabolism by optimizing pH and solvent composition. In addition, the presented method utilizes multiple scan types provided by hybrid...

  16. Ionic liquid solutions as extractive solvents for value-added compounds from biomass.

    Science.gov (United States)

    Passos, Helena; Freire, Mara G; Coutinho, João A P

    2014-12-01

    In the past few years, the number of studies regarding the application of ionic liquids (ILs) as alternative solvents to extract value-added compounds from biomass has been growing. Based on an extended compilation and analysis of the data hitherto reported, the main objective of this review is to provide an overview on the use of ILs and their mixtures with molecular solvents for the extraction of value-added compounds present in natural sources. The ILs (or IL solutions) investigated as solvents for the extraction of natural compounds, such as alkaloids, flavonoids, terpenoids, lipids, among others, are outlined. The extraction techniques employed, namely solid-liquid extraction, and microwave-assisted and ultrasound-assisted extractions, are emphasized and discussed in terms of extraction yields and purification factors. Furthermore, the evaluation of the IL chemical structure and the optimization of the process conditions (IL concentration, temperature, biomass-solvent ratio, etc.) are critically addressed. Major conclusions on the role of the ILs towards the extraction mechanisms and improved extraction yields are additionally provided. The isolation and recovery procedures of the value-added compounds are ascertained as well as some scattered strategies already reported for the IL solvent recovery and reusability. Finally, a critical analysis on the economic impact versus the extraction performance of IL-based methodologies was also carried out and is here presented and discussed.

  17. Optimization, purification and characterization of novel thermostable, haloalkaline, solvent stable protease from Bacillus halodurans CAS6 using marine shellfish wastes: a potential additive for detergent and antioxidant synthesis.

    Science.gov (United States)

    Annamalai, Neelamegam; Rajeswari, Mayavan Veeramuthu; Thavasi, Rengathavasi; Vijayalakshmi, Shanmugam; Balasubramanian, Thangavel

    2013-07-01

    A protease producing marine bacterium, Bacillus halodurans CAS6 isolated from marine sediments, was found to produce higher enzyme by utilizing shrimp shell powder. Optimum culture conditions for protease production were 50 °C, pH 9.0, 30 % NaCl and 1 % shrimp shell powder (SSP) and the protease purified with a specific activity of 509.84 U/mg. The enzyme retained 100 % of its original activity even at 70 °C, pH 10.0 and 30 % NaCl for 1 h. The purified protease exhibited higher stability when treated with ionic, non-ionic (72-94 %) and commercial detergents (76-88 %), and organic solvents (88-126 %). Significant blood stain removal activity was found with the enzyme in washing experiments. The culture supernatant supplemented with 1 % SSP showed 93.67 ± 2.52 % scavenging activity and FT-IR analysis of the reaction mixture confirmed the presence of antioxidants such as cyclohexane and cyclic depsipeptide with aliphatic amino groups. These remarkable qualities found with this enzyme produced by Bacillus halodurans CAS6 could make this as an ideal candidate to develop the industrial process for bioconversion of marine wastes and antioxidant synthesis.

  18. [The optimal blood glucose target in critically ill patient: comparison of two intensive insulin therapy protocols].

    Science.gov (United States)

    Raurell Torredà, Marta; del Llano Serrano, César; Almirall Solsona, Dolors; Catalan Ibars, Rosa María; Nicolás Arfelis, José María

    2014-03-04

    Recent studies in critically ill patients receiving insulin intravenous therapy (IIT) have shown an increased incidence of severe hypoglycemia, while intermittent subcutaneous insulin «sliding scales» (conventional insulin therapy [CIT]) is associated with hyperglycemia. The objective of this study is to assess whether glycemic control range IIT can affect glucose levels and their variability and to compare it with CIT. Prospective comparative cohort study in intensive care unit, with 2 study periods: Period 1, IIT with glycemic target range 110-140 mg/dL, and Period 2, IIT of 140-180 mg/dL. In both periods CIT glycemic target was 110-180 mg/dL. We assessed severe hypoglycemia ( 216 mg/L) and the variability of blood glucose. We studied 221 patients with 12.825 blood glucose determinations. Twenty-six and 17% of patients required IIT for glycemic control in Period 1 and 2, respectively. Hypoglycemia was associated with a discontinuous nutritional intake, glycemic target 110-140 mg/dL and low body mass index (BMI) (P = .002). Hyperglycemia was exclusively associated with a history of diabetes mellitus (OR 2.6 [95% CI 1.6 to 4.5]). Glycemic variability was associated with a discontinuous nutritional intake, low BMI, CIT insulinization, diabetes mellitus, elderly and high APACHE II (P < .001). The use of IIT is useful to reduce the variability of blood glucose. Although the 140-180 mg/dL range would be more secure as to presenting greater variability and hyperglycemia, the 110-140 mg/dL range is most suitable. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  19. Optimal task mapping in safety-critical real-time parallel systems; Placement optimal de taches pour les systemes paralleles temps-reel critiques

    Energy Technology Data Exchange (ETDEWEB)

    Aussagues, Ch

    1998-12-11

    This PhD thesis is dealing with the correct design of safety-critical real-time parallel systems. Such systems constitutes a fundamental part of high-performance systems for command and control that can be found in the nuclear domain or more generally in parallel embedded systems. The verification of their temporal correctness is the core of this thesis. our contribution is mainly in the following three points: the analysis and extension of a programming model for such real-time parallel systems; the proposal of an original method based on a new operator of synchronized product of state machines task-graphs; the validation of the approach by its implementation and evaluation. The work addresses particularly the main problem of optimal task mapping on a parallel architecture, such that the temporal constraints are globally guaranteed, i.e. the timeliness property is valid. The results incorporate also optimally criteria for the sizing and correct dimensioning of a parallel system, for instance in the number of processing elements. These criteria are connected with operational constraints of the application domain. Our approach is based on the off-line analysis of the feasibility of the deadline-driven dynamic scheduling that is used to schedule tasks inside one processor. This leads us to define the synchronized-product, a system of linear, constraints is automatically generated and then allows to calculate a maximum load of a group of tasks and then to verify their timeliness constraints. The communications, their timeliness verification and incorporation to the mapping problem is the second main contribution of this thesis. FInally, the global solving technique dealing with both task and communication aspects has been implemented and evaluated in the framework of the OASIS project in the LETI research center at the CEA/Saclay. (author) 96 refs.

  20. Optimization of Process Parameters of Extraction of Amentoflavone, Quercetin and Ginkgetin from Taxus chinensis Using Supercritical CO2 Plus Co-Solvent

    Directory of Open Access Journals (Sweden)

    Xiao Ruan

    2014-10-01

    Full Text Available The effects of extraction time, temperature, pressure and different concentration of ethanol and their interactions on the yields of amentoflavone, quercetin and ginkgetin extracted from Taxus chinensis by supercritical CO2 were investigated by using a central composite design (CCD. An CCD experimental design with four factors and five levels was used to optimize the extraction parameters. Ultra performance liquid chromatography (UPLC was used to analyze the content of the tree components in the extracts. Experimental results show that the main effects of factors and their interactions are significant on the yields (p < 0.05. The optimal extraction conditions were established for the three compounds: yield of 4.47 mg/g for amentoflavone at 48 °C, 25 MPa, 2.02 h and 78.5% ethanol, 3.73 mg/g for quercetin at 46 °C, 24 MPa, 2.3 h, 82% ethanol and 3.47 mg/g for ginkgetin at 48 °C, 20 MPa, 2.38 h, 82% ethanol, respectively.

  1. The influence of solvent processing on polyester bioabsorbable polymers.

    Science.gov (United States)

    Manson, Joanne; Dixon, Dorian

    2012-01-01

    Solvent-based methods are commonly employed for the production of polyester-based samples and coatings in both medical device production and research. The influence of solvent casting and subsequent drying time was studied using thermal analysis, spectroscopy and weight measurement for four grades of 50 : 50 poly(lactic-co-glycolic acid) (PLGA) produced by using chloroform, dichloromethane, and acetone. The results demonstrate that solvent choice and PLGA molecular weight are critical factors in terms of solvent removal rate and maintaining sample integrity, respectively. The protocols widely employed result in high levels of residual solvent and a new protocol is presented together with solutions to commonly encountered problems.

  2. Influence of Solvent-Solvent and Solute-Solvent Interaction Properties on Solvent-Mediated Potential

    International Nuclear Information System (INIS)

    Zhou Shiqi

    2005-01-01

    A recently proposed universal calculational recipe for solvent-mediated potential is applied to calculate excess potential of mean force between two large Lennard-Jones (LJ) or hard core attractive Yukawa particles immersed in small LJ solvent bath at supercritical state. Comparison between the present prediction with a hypernetted chain approximation adopted for solute-solute correlation at infinitely dilute limit and existing simulation data shows high accuracy for the region with large separation, and qualitative reliability for the solute particle contact region. The calculational simplicity of the present recipe allows for a detailed investigation on the effect of the solute-solvent and solvent-solvent interaction details on the excess potential of mean force. The resultant conclusion is that gathering of solvent particles near a solute particle leads to repulsive excess PMF, while depletion of solvent particles away from the solute particle leads to attractive excess PMF, and minor change of the solvent-solvent interaction range has large influence on the excess PMF.

  3. Towards Efficient Energy Management of Smart Buildings Exploiting Heuristic Optimization with Real Time and Critical Peak Pricing Schemes

    Directory of Open Access Journals (Sweden)

    Sheraz Aslam

    2017-12-01

    Full Text Available The smart grid plays a vital role in decreasing electricity cost through Demand Side Management (DSM. Smart homes, a part of the smart grid, contribute greatly to minimizing electricity consumption cost via scheduling home appliances. However, user waiting time increases due to the scheduling of home appliances. This scheduling problem is the motivation to find an optimal solution that could minimize the electricity cost and Peak to Average Ratio (PAR with minimum user waiting time. There are many studies on Home Energy Management (HEM for cost minimization and peak load reduction. However, none of the systems gave sufficient attention to tackle multiple parameters (i.e., electricity cost and peak load reduction at the same time as user waiting time was minimum for residential consumers with multiple homes. Hence, in this work, we propose an efficient HEM scheme using the well-known meta-heuristic Genetic Algorithm (GA, the recently developed Cuckoo Search Optimization Algorithm (CSOA and the Crow Search Algorithm (CSA, which can be used for electricity cost and peak load alleviation with minimum user waiting time. The integration of a smart Electricity Storage System (ESS is also taken into account for more efficient operation of the Home Energy Management System (HEMS. Furthermore, we took the real-time electricity consumption pattern for every residence, i.e., every home has its own living pattern. The proposed scheme is implemented in a smart building; comprised of thirty smart homes (apartments, Real-Time Pricing (RTP and Critical Peak Pricing (CPP signals are examined in terms of electricity cost estimation for both a single smart home and a smart building. In addition, feasible regions are presented for single and multiple smart homes, which show the relationship among the electricity cost, electricity consumption and user waiting time. Experimental results demonstrate the effectiveness of our proposed scheme for single and multiple smart

  4. Molecular simulations of electrolyte structure and dynamics in lithium-sulfur battery solvents

    Science.gov (United States)

    Park, Chanbum; Kanduč, Matej; Chudoba, Richard; Ronneburg, Arne; Risse, Sebastian; Ballauff, Matthias; Dzubiella, Joachim

    2018-01-01

    The performance of modern lithium-sulfur (Li/S) battery systems critically depends on the electrolyte and solvent compositions. For fundamental molecular insights and rational guidance of experimental developments, efficient and sufficiently accurate molecular simulations are thus in urgent need. Here, we construct a molecular dynamics (MD) computer simulation model of representative state-of-the art electrolyte-solvent systems for Li/S batteries constituted by lithium-bis(trifluoromethane)sulfonimide (LiTFSI) and LiNO3 electrolytes in mixtures of the organic solvents 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL). We benchmark and verify our simulations by comparing structural and dynamic features with various available experimental reference systems and demonstrate their applicability for a wide range of electrolyte-solvent compositions. For the state-of-the-art battery solvent, we finally calculate and discuss the detailed composition of the first lithium solvation shell, the temperature dependence of lithium diffusion, as well as the electrolyte conductivities and lithium transference numbers. Our model will serve as a basis for efficient future predictions of electrolyte structure and transport in complex electrode confinements for the optimization of modern Li/S batteries (and related devices).

  5. Hazardous solvent substitution

    International Nuclear Information System (INIS)

    Twitchell, K.E.

    1995-01-01

    This article is an overview of efforts at INEL to reduce the generation of hazardous wastes through the elimination of hazardous solvents. To aid in their efforts, a number of databases have been developed and will become a part of an Integrated Solvent Substitution Data System. This latter data system will be accessible through Internet

  6. Optimization by simulation of the coupling between a sub-critical reactor and its spallation source. Towards a pilot reactor

    International Nuclear Information System (INIS)

    Kerdraon, D.

    2001-10-01

    Accelerator Driven Systems (ADS), based on a proton accelerator and a sub-critical core coupled with a spallation target, offer advantages in order to reduce the nuclear waste radiotoxicity before repository closure. Many studies carried out on the ADS should lead to the definition of an experimental plan which would federate the different works in progress. This thesis deals with the neutronic Monte Carlo simulations with the MCNPX code to optimize such a system in view of a pilot reactor building. First, we have recalled the main neutronic properties of an hybrid reactor. The concept of gas-cooled eXperimental Accelerator Driven System (XADS) chosen for our investigations comes from the preliminary studies done by the Framatome company. In order to transmute minor actinides, we have considered the time evolution of the main fuels which could be reasonably used for the demonstration phases. The neutronic parameters of the reactor, concerning minor actinide transmutation, are reported. Also, we have calculated the characteristic times and the transmutation rates in the case of 99 Tc and 129 I isotopes. We have identified some neutronic differences between an experimental and a power ADS according to the infinite multiplication coefficient, the shape factor and the level of flux to extend the demonstrator concept. We have proposed geometric solutions to keep the radial shape factor of a power ADS acceptable. In the last part, beyond the experimental XADS scope, we have examined the possible transition towards an uranium/thorium cycle based on Molten Salt Reactors using a power ADS in order to generate the required 233 U proportion. (author)

  7. Solvent - solute interaction

    International Nuclear Information System (INIS)

    Urbanczyk, A.; Kalinowski, M.K.

    1983-01-01

    The electronic absorption spectrum of vanadyl acetylacetonate has been studied in 15 organic solvents. It has been found that wavenumbers and molar absorptivities of the long-wavelength bands (d-d transitions) can be well described by a complementary Lewis acid-base model including Gutmann's donor number [Gutmann V., Wychera E., Inorg. Nucl. Chem. Letters 2, 257 (1966)] and acceptor number [Mayer U., Gutmann V., Gerger W., Monatsh. Chem. 106, 1235 (1975)] of a solvent. This model describes also the solvent effect of the hyperfine splitting constant, Asub(iso)( 51 V), from e.s.r. spectra of VOacac 2 . These observations are discussed in terms of the donor-acceptor concept for solvent-solute interactions. (Author)

  8. Cesium Removal from Savannah River Site Radioactive Waste Using the Caustic Side Solvent Extraction (CSSX) Process

    International Nuclear Information System (INIS)

    WALKER, DARREL

    2004-01-01

    Researchers at the Savannah River Technology Center (SRTC) successfully demonstrated the Caustic-Side Solvent Extraction (CSSX) process flow sheet using a 33-stage, 2-cm centrifugal contactor apparatus in two 24-hour tests using actual high level waste. Previously, we demonstrated the solvent extraction process with actual SRS HLW supernatant solution using a non-optimized solvent formulation. Following that test, the solvent system was optimized to enhance extractant solubility in the diluent by increasing the modifier concentration. We now report results of two tests with the new and optimized solvent

  9. Recovery of acid-degraded tributyl phosphate by solvent extraction

    International Nuclear Information System (INIS)

    Young, G.C.; Holladay, D.W.

    1981-01-01

    During nuclear fuel reprocessing the organic solvent becomes loaded with various acidic degradation products, which can be effectively removed through solvent extraction. Studies have been made with a small bench-scale solvent extraction system to optimize such parameters as pH of aqueous phase, phase ratio, residence time, flow rates, and temperature. The necessary decontamination factors have been obtained for various degradation products during continuous solvent extraction in one stage, with the aqueous phase being recycled. The aqueous phase contains compounds that can be degraded to gases to minimize waste disposal problems

  10. Morin-based nanofiltration membranes for organic solvent separation processes

    KAUST Repository

    Perez Manriquez, Liliana; Neelakanda, Pradeep; Peinemann, Klaus-Viktor

    2018-01-01

    In this work we demonstrate the successful optimization of the interfacial polymerization reaction for the manufacture of organic solvent nanofiltration membranes by replacing the toxic amines commonly used for this method with the natural occurring

  11. Two-Phase Iteration for Value Function Approximation and Hyperparameter Optimization in Gaussian-Kernel-Based Adaptive Critic Design

    OpenAIRE

    Chen, Xin; Xie, Penghuan; Xiong, Yonghua; He, Yong; Wu, Min

    2015-01-01

    Adaptive Dynamic Programming (ADP) with critic-actor architecture is an effective way to perform online learning control. To avoid the subjectivity in the design of a neural network that serves as a critic network, kernel-based adaptive critic design (ACD) was developed recently. There are two essential issues for a static kernel-based model: how to determine proper hyperparameters in advance and how to select right samples to describe the value function. They all rely on the assessment of sa...

  12. NOVEL POLYMERIC MEMBRANE FOR DEHYDRATION OF ORGANIC SOLVENTS

    Science.gov (United States)

    Pervaporation has emerged as an economically viable alternative technology for dehydration of organic solvents, removal of organic compounds and organic/organic separations. Development of a membrane system with suitable flux and selectivity characteristics plays a critical role...

  13. Purex process solvent: literature review

    Energy Technology Data Exchange (ETDEWEB)

    Geier, R.G.

    1979-10-01

    This document summarizes the data on Purex process solvent presently published in a variety of sources. Extracts from these various sources are presented herein and contain the work done, the salient results obtained, and the original, unaltered conclusions of the author of each paper. Three major areas are addressed: solvent stability, solvent quality testing, and solvent treatment processes. 34 references, 44 tables.

  14. Purex process solvent: literature review

    International Nuclear Information System (INIS)

    Geier, R.G.

    1979-10-01

    This document summarizes the data on Purex process solvent presently published in a variety of sources. Extracts from these various sources are presented herein and contain the work done, the salient results obtained, and the original, unaltered conclusions of the author of each paper. Three major areas are addressed: solvent stability, solvent quality testing, and solvent treatment processes. 34 references, 44 tables

  15. Neural-Network-Based Robust Optimal Tracking Control for MIMO Discrete-Time Systems With Unknown Uncertainty Using Adaptive Critic Design.

    Science.gov (United States)

    Liu, Lei; Wang, Zhanshan; Zhang, Huaguang

    2018-04-01

    This paper is concerned with the robust optimal tracking control strategy for a class of nonlinear multi-input multi-output discrete-time systems with unknown uncertainty via adaptive critic design (ACD) scheme. The main purpose is to establish an adaptive actor-critic control method, so that the cost function in the procedure of dealing with uncertainty is minimum and the closed-loop system is stable. Based on the neural network approximator, an action network is applied to generate the optimal control signal and a critic network is used to approximate the cost function, respectively. In contrast to the previous methods, the main features of this paper are: 1) the ACD scheme is integrated into the controllers to cope with the uncertainty and 2) a novel cost function, which is not in quadric form, is proposed so that the total cost in the design procedure is reduced. It is proved that the optimal control signals and the tracking errors are uniformly ultimately bounded even when the uncertainty exists. Finally, a numerical simulation is developed to show the effectiveness of the present approach.

  16. Separation by solvent extraction

    International Nuclear Information System (INIS)

    Holt, C.H. Jr.

    1976-01-01

    In a process for separating fission product values from U and Pu values contained in an aqueous solution, an oxidizing agent is added to the solution to secure U and Pu in their hexavalent state. The aqueous solution is contacted with a substantially water-immiscible organic solvent with agitation while the temperature is maintained at from -1 to -2 0 C until the major part of the water present is frozen. The solid ice phase is continuously separated as it is formed and a remaining aqueous liquid phase containing fission product values and a solvent phase containing Pu and U values are separated from each other. The last obtained part of the ice phase is melted and added to the separated liquid phase. The resulting liquid is treated with a new supply of solvent whereby it is practically depleted of U and Pu

  17. A framework for model-based optimization of bioprocesses under uncertainty: Identifying critical parameters and operating variables

    DEFF Research Database (Denmark)

    Morales Rodriguez, Ricardo; Meyer, Anne S.; Gernaey, Krist

    2011-01-01

    This study presents the development and application of a systematic model-based framework for bioprocess optimization, evaluated on a cellulosic ethanol production case study. The implementation of the framework involves the use of dynamic simulations, sophisticated uncertainty analysis (Monte...

  18. Theory of polyelectrolytes in solvents.

    Science.gov (United States)

    Chitanvis, Shirish M

    2003-12-01

    Using a continuum description, we account for fluctuations in the ionic solvent surrounding a Gaussian, charged chain and derive an effective short-ranged potential between the charges on the chain. This potential is repulsive at short separations and attractive at longer distances. The chemical potential can be derived from this potential. When the chemical potential is positive, it leads to a meltlike state. For a vanishingly low concentration of segments, this state exhibits scaling behavior for long chains. The Flory exponent characterizing the radius of gyration for long chains is calculated to be approximately 0.63, close to the classical value obtained for second order phase transitions. For short chains, the radius of gyration varies linearly with N, the chain length, and is sensitive to the parameters in the interaction potential. The linear dependence on the chain length N indicates a stiff behavior. The chemical potential associated with this interaction changes sign, when the screening length in the ionic solvent exceeds a critical value. This leads to condensation when the chemical potential is negative. In this state, it is shown using the mean-field approximation that spherical and toroidal condensed shapes can be obtained. The thickness of the toroidal polyelectrolyte is studied as a function of the parameters of the model, such as the ionic screening length. The predictions of this theory should be amenable to experimental verification.

  19. Hydrogenation of diesel aromatic compounds in supercritical solvent environment

    Directory of Open Access Journals (Sweden)

    E.P. Martins

    2000-09-01

    Full Text Available Reactions under supercritical conditions have been employed in many processes. Furthermore, an increasing number of commercial reactions have been conducted under supercritical or near critical conditions. These reaction conditions offer several advantages when compared to conditions in conventional catalytic processes in liquid-phase, gas-liquid interface, or even some gas-phase reactions. Basically, a supercritical solvent can diminish the reactant’s transport resistance from the bulk region to the catalyst surface due to enhancement of liquid diffusivity values and better solubility than those in different phases. Another advantage is that supercritical solvents permit prompt and easy changes in intermolecular properties in order to modify reaction parameters, such as conversion or selectivity, or even proceed with the separation of reaction products. Diesel fractions from petroleum frequently have larger than desirable quantities of aromatic compounds. Diesel hydrogenation is intended to decrease these quantities, i.e., to increase the quantity of paraffin present in this petroleum fraction. In this work, the hydrogenation of tetralin was studied as a model reaction for the aromatic hydrogenation process. A conventional gas-liquid-solid catalytic process was compared with that of supercritical carbon dioxide substrate under similar conditions. Additionally, an equilibrium conversion diagram was calculated for this reaction in a wide range of temperature and reactant ratios, so as to optimize the operational conditions and improve the results of subsequent experiments. An increase in the rate of reaction at 493 K in supercritical fluid, as compared to that in the conventional process, was observed.

  20. Solvent anode for plutonium purification

    International Nuclear Information System (INIS)

    Bowersox, D.F.; Fife, K.W.; Christensen, D.C.

    1986-01-01

    The purpose of this study is to develop a technique to allow complete oxidation of plutonium from the anode during plutonium electrorefining. This will eliminate the generation of a ''spent'' anode heel which requires further treatment for recovery. Our approach is to employ a solvent metal in the anode to provide a liquid anode pool throughout electrorefining. We use molten salts and metals in ceramic crucibles at 700 0 C. Our goal is to produce plutonium metal at 99.9% purity with oxidation and transfer of more than 98% of the impure plutonium feed metal from the anode into the salt and product phases. We have met these criteria in experiments on the 100 to 1000 g scale. We plan to scale our operations to 4 kg of feed plutonium and to optimize the process parameters

  1. Organic solvent topical report

    Energy Technology Data Exchange (ETDEWEB)

    COWLEY, W.L.

    1999-05-13

    This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an organic solvent fire is within risk evaluation guidelines. This report updates information contained in Analysis of Consequences of Postulated Solvent Fires in Hanford Site Waste Tanks. WHC-SD-WM-CN-032. Rev. 0A (Cowley et al. 1996). However, this document will not replace Cowley et al (1996) as the primary reference for the Basis for Interim Operation (BIO) until the recently submitted BIO amendment (Hanson 1999) is approved by the US Department of Energy. This conclusion depends on the use of controls for preventing vehicle fuel fires and for limiting the use of flame cutting in areas where hot metal can fall on the waste surface.The required controls are given in the Tank Waste Remediation System Technical Safety Requirements (Noorani 1997b). This is a significant change from the conclusions presented in Revision 0 of this report. Revision 0 of this calcnote concluded that some organic solvent fire scenarios exceeded risk evaluation guidelines, even with controls imposed.

  2. Organic solvent topical report

    Energy Technology Data Exchange (ETDEWEB)

    Cowley, W.L.

    1998-04-30

    This report is the technical basis for the accident and consequence analyses used in the Hanford Tank Farms Basis for Interim Operation. The report also contains the scientific and engineering information and reference material needed to understand the organic solvent safety issue. This report includes comments received from the Chemical Reactions Subcommittee of the Tank Advisory Panel.

  3. Organic solvent topical report

    International Nuclear Information System (INIS)

    COWLEY, W.L.

    1999-01-01

    This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an organic solvent fire is within risk evaluation guidelines. This report updates information contained in Analysis of Consequences of Postulated Solvent Fires in Hanford Site Waste Tanks. WHC-SD-WM-CN-032. Rev. 0A (Cowley et al. 1996). However, this document will not replace Cowley et al (1996) as the primary reference for the Basis for Interim Operation (BIO) until the recently submitted BIO amendment (Hanson 1999) is approved by the US Department of Energy. This conclusion depends on the use of controls for preventing vehicle fuel fires and for limiting the use of flame cutting in areas where hot metal can fall on the waste surface.The required controls are given in the Tank Waste Remediation System Technical Safety Requirements (Noorani 1997b). This is a significant change from the conclusions presented in Revision 0 of this report. Revision 0 of this calcnote concluded that some organic solvent fire scenarios exceeded risk evaluation guidelines, even with controls imposed

  4. Organic solvent topical report

    International Nuclear Information System (INIS)

    Cowley, W.L.

    1998-01-01

    This report is the technical basis for the accident and consequence analyses used in the Hanford Tank Farms Basis for Interim Operation. The report also contains the scientific and engineering information and reference material needed to understand the organic solvent safety issue. This report includes comments received from the Chemical Reactions Subcommittee of the Tank Advisory Panel

  5. DESIGNING GREENER SOLVENTS

    Science.gov (United States)

    Computer-aided design of chemicals and chemical mixtures provides a powerful tool to help engineers identify cleaner process designs and more-benign alternatives to toxic industrial solvents. Three software programs are discussed: (1) PARIS II (Program for Assisting the Replaceme...

  6. Critical thermodynamic evaluation and optimization of the Fe–B, Fe–Nd, B–Nd and Nd–Fe–B systems

    International Nuclear Information System (INIS)

    Van Ende, Marie-Aline; Jung, In-Ho

    2013-01-01

    Highlights: ► Complete critical evaluation of all available phase diagram and thermodynamic data for the Fe–Nd–B system for the first time. ► Thermodynamic database of optimized model parameters has been developed. ► Gibbs energies of binary and ternary solid and liquid phases were properly described. ► All reliable thermodynamic and phase diagram data were properly reproduced. ► Liquidus projection of the Fe–Nd–B system is properly predicted for the first time. - Abstract: All experimental data on phase equilibria and thermodynamic properties of the Fe–B, Fe–Nd and Nd–B binary and Fe–Nd–B ternary systems in literature were reviewed and critically examined. A set of optimized model parameters for all solid stoichiometric compounds, solid solutions and liquid phase was built to reproduce all available reliable thermodynamic properties and phase diagram data within experimental error limits. The solid solutions were modeled using the Compound Energy Formalism. The Modified Quasichemical Model in the pair approximation was used to describe the thermodynamic properties of the liquid solution accurately. The database of the model parameters can be used, along with the software for Gibbs energy minimization, to calculate any type of phase diagram section. Unexplored liquidus projection of the Fe–Nd–B ternary system was predicted from the thermodynamic models and optimized parameters.

  7. GPU-based stochastic-gradient optimization for non-rigid medical image registration in time-critical applications

    NARCIS (Netherlands)

    Staring, M.; Al-Ars, Z.; Berendsen, Floris; Angelini, Elsa D.; Landman, Bennett A.

    2018-01-01

    Currently, non-rigid image registration algorithms are too computationally intensive to use in time-critical applications. Existing implementations that focus on speed typically address this by either parallelization on GPU-hardware, or by introducing methodically novel techniques into

  8. Freeze drying optimization of polymeric nanoparticles for ocular flurbiprofen delivery: effect of protectant agents and critical process parameters on long-term stability.

    Science.gov (United States)

    Ramos Yacasi, Gladys Rosario; Calpena Campmany, Ana Cristina; Egea Gras, María Antonia; Espina García, Marta; García López, María Luisa

    2017-04-01

    The stabilization of flurbiprofen loaded poly-ɛ-caprolactone nanoparticles (FB-PɛCL-NPs) for ocular delivery under accurate freeze-drying (FD) process provides the basis for a large-scale production and its commercial development. Optimization of the FD to improve long-term stability of ocular administration's FB-PɛCL-NPs. FB-PɛCL-NPs were prepared by solvent displacement method with poloxamer 188 (P188) as stabilizer. Freezing and primary drying (PD) were studied and optimized through freeze-thawing test and FD microscopy. Design of experiments was used to accurate secondary drying (SD) conditions and components concentration. Formulations were selected according to desired physicochemical properties. Furthermore, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to study interactions components. Optimized FB-PɛCL-NPs, stabilized with 3.5% (w/w) P188 and protected with 8% (w/w) poly(ethylene glycol), was submitted to precooling at +10 °C for 1 h, freezing at -50 °C for 4 h, PD at +5 °C and 0.140 mbar for 24 h and a SD at +45 °C during 10 h. These conditions showed 188.4 ± 1.3 nm, 0.087 ± 0.014, 85.5 ± 1.4%, 0.61 ± 0.12%, -16.4 ± 0.1 mV and 325 ± 7 mOsm/kg of average size, polydispersity index, entrapment efficiency, residual moisture, surface charge and osmolality, respectively. It performed a long-term stability >12 months. DSC and XRD spectra confirmed adequate chemical interaction between formulation components and showed a semi-crystalline state after FD. An optimal freeze dried ocular formulation was achieved. Evidently, the successful design of this promising colloidal system resulted from rational cooperation between a good formulation and the right conditions in the FD process.

  9. Novel power flow problem solutions method’s based on genetic algorithm optimization for banks capacitor compensation using an fuzzy logic rule bases for critical nodal detections

    OpenAIRE

    Abdelfatah, Nasri; Brahim, Gasbaoui

    2011-01-01

    The Reactive power flow’s is one of the most electrical distribution systems problem wich have great of interset of the electrical network researchers, it’s  cause’s active power transmission reduction, power losses decreasing, and  the drop voltage’s increase. In this research we described the efficiency of the FLC-GAO approach to solve the optimal power flow (OPF) combinatorial problem. The proposed approach employ tow algorithms, Fuzzy logic controller (FLC) algorithm for critical nodal de...

  10. Neutronics optimization of LiPb-He dual-cooled fuel breeding blanket for the fusion-driven sub-critical system

    International Nuclear Information System (INIS)

    Zheng Shanliang; Wu Yican

    2002-01-01

    The concept of the liquid Li 17 Pb 83 and Helium gas dual-cooled Fuel Breeding Blanket (FBB) for the Fusion-Driven sub-critical System (FDS) is presented and analyzed. Taking self-sustaining tritium (TBR > 1.05) and annual output of 100 kg or more fissile 239 Pu (FBR > 0.238) as objective parameters, and based on the three-dimensional Monte Carlo neutron-photon transport code MCNP/4A, a neutronics-optimized calculation of different cases was carried out and the concept is proved feasible. In addition, the total breeding ratio (Br = Tbr + Fbr) is listed corresponding to different cases

  11. Optimizing therapeutic efficacy of chemopreventive agents: A critical review of delivery strategies in oral cancer chemoprevention clinical trials

    OpenAIRE

    Andrew S Holpuch; Kashappa-Goud H Desai; Steven P Schwendeman; Susan R Mallery

    2011-01-01

    Due to its characterized progression from recognized premalignant oral epithelial changes (i.e., oral epithelial dysplasia) to invasive cancer, oral squamous cell carcinoma represents an optimal disease for chemopreventive intervention prior to malignant transformation. The primary goal of oral cancer chemoprevention is to reverse, suppress, or inhibit the progression of premalignant lesions to cancer. Over the last several decades, numerous oral cancer chemoprevention clinical trials have as...

  12. Solvent selection methodology for pharmaceutical processes: Solvent swap

    DEFF Research Database (Denmark)

    Papadakis, Emmanouil; Kumar Tula, Anjan; Gani, Rafiqul

    2016-01-01

    A method for the selection of appropriate solvents for the solvent swap task in pharmaceutical processes has been developed. This solvent swap method is based on the solvent selection method of Gani et al. (2006) and considers additional selection criteria such as boiling point difference...... in pharmaceutical processes as well as new solvent swap alternatives. The method takes into account process considerations such as batch distillation and crystallization to achieve the swap task. Rigorous model based simulations of the swap operation are performed to evaluate and compare the performance...

  13. Improvements in solvent extraction columns

    International Nuclear Information System (INIS)

    Aughwane, K.R.

    1987-01-01

    Solvent extraction columns are used in the reprocessing of irradiated nuclear fuel. For an effective reprocessing operation a solvent extraction column is required which is capable of distributing the feed over most of the column. The patent describes improvements in solvent extractions columns which allows the feed to be distributed over an increased length of column than was previously possible. (U.K.)

  14. Solvent extraction columns

    International Nuclear Information System (INIS)

    Middleton, P.; Smith, J.R.

    1979-01-01

    In pulsed columns for use in solvent extraction processes, e.g. the reprocessing of nuclear fuel, the horizontal perforated plates inside the column are separated by interplate spacers manufactured from metallic neutron absorbing material. The spacer may be in the form of a spiral or concentric circles separated by radial limbs, or may be of egg-box construction. Suitable neutron absorbing materials include stainless steel containing boron or gadolinium, hafnium metal or alloys of hafnium. (UK)

  15. Hazardous solvent substitution

    International Nuclear Information System (INIS)

    Twitchell, K.E.

    1995-01-01

    Eliminating hazardous solvents is good for the environment, worker safety, and the bottom line. However, even though we are motivated to find replacements, the big question is 'What can we use as replacements for hazardous solvents?'You, too, can find replacements for your hazardous solvents. All you have to do is search for them. Search through the vendor literature of hundreds of companies with thousands of products. Ponder the associated material safety data sheets, assuming of course that you can obtain them and, having obtained them, that you can read them. You will want to search the trade magazines and other sources for product reviews. You will want to talk to users about how well the product actually works. You may also want to check US Environmental Protection Agency (EPA) and other government reports for toxicity and other safety information. And, of course, you will want to compare the product's constituent chemicals with the many hazardous constituency lists to ensure the safe and legal use of the product in your workplace

  16. SOLVENT FIRE BY-PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D; Samuel Fink, S

    2006-05-22

    Southwest Research Institute (SwRI) conducted a burn test of the Caustic-Side Solvent Extraction (CSSX) solvent to determine the combustion products. The testing showed hydrogen fluoride gas is not a combustion product from a solvent fire when up to 70% of the solvent is consumed. The absence of HF in the combustion gases may reflect concentration of the modifier containing the fluoride groups in the unburned portion. SwRI reported results for other gases (CO, HCN, NOx, formaldehyde, and hydrocarbons). The results, with other supporting information, can be used for evaluating the consequences of a facility fire involving the CSSX solvent inventory.

  17. Optimization of the representativeness and transposition approach, for the neutronic design of experimental programs in critical mock-up

    International Nuclear Information System (INIS)

    Dos-Santos, N.

    2013-01-01

    The work performed during this thesis focused on uncertainty propagation (nuclear data, technological uncertainties, calculation biases,...) on integral parameters, and the development of a novel approach enabling to reduce this uncertainty a priori directly from the design phase of a new experimental program. This approach is based on a multi-parameter multi-criteria extension of representativeness and transposition theories. The first part of this PhD work covers an optimization study of sensitivity and uncertainty calculation schemes to different modeling scales (cell, assembly and whole core) for LWRs and FBRs. A degraded scheme, based on standard and generalized perturbation theories, has been validated for the calculation of uncertainty propagation to various integral quantities of interest. It demonstrated the good a posteriori representativeness of the EPICURE experiment for the validation of mixed UOX-MOX loadings, as the importance of some nuclear data in the power tilt phenomenon in large LWR cores. The second part of this work was devoted to methods and tools development for the optimized design of experimental programs in ZPRs. Those methods are based on multi-parameters representativeness using simultaneously various quantities of interest. Finally, an original study has been conducted on the rigorous estimation of correlations between experimental programs in the transposition process. The coupling of experimental correlations and multi-parametric representativeness approach enables to efficiently design new programs, able to answer additional qualification requirements on calculation tools. (author) [fr

  18. Expanding solvent SAGD in heavy oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Govind, P.A. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[ConocoPhillips Canada Resources Corp., Calgary, AB (Canada); Das, S.; Wheeler, T.J. [Society of Petroleum Engineers, Richardson, TX (United States)]|[ConocoPhillips Co., Houston, TX (United States); Srinivasan, S. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Texas Univ., Austin, TX (United States)

    2008-10-15

    Steam assisted gravity drainage (SAGD) projects have proven effective for the recovery of oil and bitumen. Expanding solvent (ES) SAGD pilot projects have also demonstrated positive results of improved performance. This paper presented the results of a simulation study that investigated several important factors of the ES-SAGD process, including solvent types; concentration; operating pressure; and injection strategy. The objectives of the study were to examine the effectiveness of the ES-SAGD process in terms of production acceleration and energy requirements; to optimize solvent selection; to understand the effect of dilation in unconsolidated oil sands and the directional impact on reservoir parameters and oil production rate in ES-SAGD; and to understand the impact of operating conditions such as pressure, solvent concentration, circulation preheating period and the role of conduction heating and grid size in this process. The advantages of ES-SAGD over SAGD were also outlined. The paper presented results of sensitivity studies that were conducted on these four factors. Conclusions and recommendations for operating strategy were also offered. It was concluded that dilation is an important factor for SAGD performance at high operating pressure. 8 refs., 15 figs.

  19. Essential roles of protein-solvent many-body correlation in solvent-entropy effect on protein folding and denaturation: Comparison between hard-sphere solvent and water

    International Nuclear Information System (INIS)

    Oshima, Hiraku; Kinoshita, Masahiro

    2015-01-01

    In earlier works, we showed that the entropic effect originating from the translational displacement of water molecules plays the pivotal role in protein folding and denaturation. The two different solvent models, hard-sphere solvent and model water, were employed in theoretical methods wherein the entropic effect was treated as an essential factor. However, there were similarities and differences in the results obtained from the two solvent models. In the present work, to unveil the physical origins of the similarities and differences, we simultaneously consider structural transition, cold denaturation, and pressure denaturation for the same protein by employing the two solvent models and considering three different thermodynamic states for each solvent model. The solvent-entropy change upon protein folding/unfolding is decomposed into the protein-solvent pair (PA) and many-body (MB) correlation components using the integral equation theories. Each component is further decomposed into the excluded-volume (EV) and solvent-accessible surface (SAS) terms by applying the morphometric approach. The four physically insightful constituents, (PA, EV), (PA, SAS), (MB, EV), and (MB, SAS), are thus obtained. Moreover, (MB, SAS) is discussed by dividing it into two factors. This all-inclusive investigation leads to the following results: (1) the protein-water many-body correlation always plays critical roles in a variety of folding/unfolding processes; (2) the hard-sphere solvent model fails when it does not correctly reproduce the protein-water many-body correlation; (3) the hard-sphere solvent model becomes problematic when the dependence of the many-body correlation on the solvent number density and temperature is essential: it is not quite suited to studies on cold and pressure denaturating of a protein; (4) when the temperature and solvent number density are limited to the ambient values, the hard-sphere solvent model is usually successful; and (5) even at the ambient

  20. Solvent Extraction and Characterization of Neutral Lipids in Oocystis sp

    Energy Technology Data Exchange (ETDEWEB)

    Anthony, Renil [Department of Mechanical Engineering, Ohio University, Athens, OH (United States); Stuart, Ben, E-mail: stuart@ohio.edu [Department of Civil Engineering, Ohio University, Athens, OH (United States)

    2015-01-20

    Microalgae are a favorable feedstock for bioproducts and biofuels due to their high oil content, fast growth rates, and low resource demands. Solvent lipid extraction efficiency from microalgae is dependent on algal strain and the extraction solvent. Four non-polar extraction solvents were evaluated for the recovery of neutral cellular lipids from microalgae Oocystis sp. (University of Texas at Austin LB2396). Methylene chloride, hexane, diethyl ether, and cyclohexane were selected as the extraction solvents. The lipid extracts were derivatized and analyzed using gas chromatography–mass spectroscopy. All solvent extracts contained hexadecanoic acid, linoleic acid, and linolenic acid; accounting for 70% of total lipid content with a proportional wt% composition of the three fatty acids, except for the hexane extracts that showed only hexadecanoic acid and linoleic acid. While not statistically differentiated, methylene chloride proved to be the most effective solvent for Oocystis sp. among the four solvents tested with a total average neutral lipid recovery of 0.25% of dry weight followed by diethyl ether (0.18%), cyclohexane (0.14%), and hexane (0.11%). This research presents a simple methodology to optimize the selection of lipid specific extraction solvents for the microalgal strain selected.

  1. Solvent Extraction and Characterization of Neutral Lipids in Oocystis sp.

    Directory of Open Access Journals (Sweden)

    Renil eAnthony

    2015-01-01

    Full Text Available Microalgae are a favorable feedstock for bioproducts and biofuels due to their high oil content, fast growth rates and low resource demands. Solvent lipid extraction efficiency from microalgae is dependent on algal strain and the extraction solvent. Four non-polar extraction solvents were evaluated for the recovery of neutral cellular lipids from microalgae Oocystis sp. (UTEX LB2396. Methylene chloride, hexane, diethyl ether, and cyclohexane were selected as the extraction solvents. All solvent extracts contained hexadecanoic acid, linoleic acid and linolenic acid; accounting for 70% of total lipid content with a proportional wt% composition of the three fatty acids, except for the hexane extracts that showed only hexadecanoic acid and linoleic acid. While not statistically differentiated, methylene chloride proved to be the most effective solvent for Oocystis sp. among the four solvents tested with a total average neutral lipid recovery of 0.25% of dry weight followed by diethyl ether (0.18%, cyclohexane (0.14% and hexane (0.11%. This research presents a simple methodology to optimize the selection of lipid specific extraction solvents for the microalgal strain selected.

  2. Solvent Extraction and Characterization of Neutral Lipids in Oocystis sp

    International Nuclear Information System (INIS)

    Anthony, Renil; Stuart, Ben

    2015-01-01

    Microalgae are a favorable feedstock for bioproducts and biofuels due to their high oil content, fast growth rates, and low resource demands. Solvent lipid extraction efficiency from microalgae is dependent on algal strain and the extraction solvent. Four non-polar extraction solvents were evaluated for the recovery of neutral cellular lipids from microalgae Oocystis sp. (University of Texas at Austin LB2396). Methylene chloride, hexane, diethyl ether, and cyclohexane were selected as the extraction solvents. The lipid extracts were derivatized and analyzed using gas chromatography–mass spectroscopy. All solvent extracts contained hexadecanoic acid, linoleic acid, and linolenic acid; accounting for 70% of total lipid content with a proportional wt% composition of the three fatty acids, except for the hexane extracts that showed only hexadecanoic acid and linoleic acid. While not statistically differentiated, methylene chloride proved to be the most effective solvent for Oocystis sp. among the four solvents tested with a total average neutral lipid recovery of 0.25% of dry weight followed by diethyl ether (0.18%), cyclohexane (0.14%), and hexane (0.11%). This research presents a simple methodology to optimize the selection of lipid specific extraction solvents for the microalgal strain selected.

  3. Novel Power Flow Problem Solutions Method’s Based on Genetic Algorithm Optimization for Banks Capacitor Compensation Using an Fuzzy Logic Rule Bases for Critical Nodal Detections

    Directory of Open Access Journals (Sweden)

    Nasri Abdelfatah

    2011-01-01

    Full Text Available The Reactive power flow’s is one of the most electrical distribution systems problem wich have great of interset of the electrical network researchers, it’s  cause’s active power transmission reduction, power losses decreasing, and  the drop voltage’s increase. In this research we described the efficiency of the FLC-GAO approach to solve the optimal power flow (OPF combinatorial problem. The proposed approach employ tow algorithms, Fuzzy logic controller (FLC algorithm for critical nodal detection and gentic algorithm  optimization (GAO algorithm for optimal seizing capacitor.GAO method is more efficient in combinatory problem solutions. The proposed approach has been examined and tested on the standard IEEE 57-bus the resulats show the power loss minimization denhancement, voltage profile, and stability improvement. The proposed approach results have been compared to those that reported in the literature recently. The results are promising and show the effectiveness and robustness of the proposed approach.

  4. Optimization of Critical Hairpin Features Allows miRNA-based Gene Knockdown Upon Single-copy Transduction

    Directory of Open Access Journals (Sweden)

    Renier Myburgh

    2014-01-01

    Full Text Available Gene knockdown using micro RNA (miRNA-based vector constructs is likely to become a prominent gene therapy approach. It was the aim of this study to improve the efficiency of gene knockdown through optimizing the structure of miRNA mimics. Knockdown of two target genes was analyzed: CCR5 and green fluorescent protein. We describe here a novel and optimized miRNA mimic design called mirGE comprising a lower stem length of 13 base pairs (bp, positioning of the targeting strand on the 5′ side of the miRNA, together with nucleotide mismatches in upper stem positions 1 and 12 placed on the passenger strand. Our mirGE proved superior to miR-30 in four aspects: yield of targeting strand incorporation into RNA-induced silencing complex (RISC; incorporation into RISC of correct targeting strand; precision of cleavage by Drosha; and ratio of targeting strand over passenger strand. A triple mirGE hairpin cassette targeting CCR5 was constructed. It allowed CCR5 knockdown with an efficiency of over 90% upon single-copy transduction. Importantly, single-copy expression of this construct rendered transduced target cells, including primary human macrophages, resistant to infection with a CCR5-tropic strain of HIV. Our results provide new insights for a better knockdown efficiency of constructs containing miRNA. Our results also provide the proof-of-principle that cells can be rendered HIV resistant through single-copy vector transduction, rendering this approach more compatible with clinical applications.

  5. The reduction of optimal heat treatment temperature and critical current density enhancement of ex situ processed MgB2 tapes using ball milled filling powder

    Science.gov (United States)

    Fujii, Hiroki; Iwanade, Akio; Kawada, Satoshi; Kitaguchi, Hitoshi

    2018-01-01

    The optimal heat treatment temperature (Topt) at which best performance in the critical current density (Jc) property at 4.2 K is obtained is influenced by the quality or reactivity of the filling powder in ex situ processed MgB2 tapes. Using a controlled fabrication process, the Topt decreases to 705-735 °C, which is lower than previously reported by more than 50 °C. The Topt decrease is effective to suppress both the decomposition of MgB2 and hence the formation of impurities such as MgB4, and the growth of crystallite size which decreases upper critical filed (Hc2). These bring about the Jc improvement and the Jc value at 4.2 K and 10 T reaches 250 A/mm2. The milling process also decreases the critical temperature (Tc) below 30 K. The milled powder is easily contaminated in air and thus, the Jc property of the contaminated tapes degrades severely. The contamination can raise the Topt by more than 50 °C, which is probably due to the increased sintering temperature required against contaminated surface layer around the grains acting as a barrier.

  6. Ecological tax reform - an optimal solution?. Critical remarks on the DIW study ''Economic effects of an ecological tax reform''

    International Nuclear Information System (INIS)

    Boehringer, C.; Fahl, H.; Voss, A.

    1994-01-01

    Through the latest expertise of the German institute for economic research (DIW) regarding an ecological tax reform, the discussion about a tax system considering the shortage of the ressource environment and a deficiency of demand regarding the ressource work is newly provoked. The focus of this article is a critical dealing with the methodical procedure of the German institute for economic reserarch when analyzing the national economic effect of a concretely formulated ecological tax law scenario. When assessing the overall economic consequences of a tax reform, it is recommended to use an analysis instrument, which is farly more consistent compared to the instruments by DIW, and which is more problem adequate through the increased resort to financial knowledge. Based on the obvious weakness of the DIW study, a more extensive comprehension for an ecological tax reform is pleaded for, standing out for an application of taxes based on division of labour and oriented to the objective. (orig./UA) [de

  7. Clinical and preclinical validation of the serum free light chain assay: identification of the critical difference for optimized clinical use.

    Science.gov (United States)

    Hansen, Charlotte T; Münster, Anna-Marie; Nielsen, Lars; Pedersen, Per; Abildgaard, Niels

    2012-12-01

    The use of the assay for the measurements of free light chains in serum (sFLCs) is increasing. However, there are technical limitations that potentially affect the use in serial measurements. We need further knowledge on the standards of analytical precision, the utility of conventional population-based reference values and the critical difference (CD) between serial results required for significance. To answer these questions, the biological variation must be known. We determined the biological variation in healthy individuals and patients with plasma cell dyscrasia (PCD). We assessed the imprecision of the analysis in use from FreeLite™. We determined the reference interval (RI) in 170 healthy individuals. The biological variation is identical for healthy individuals and patients with PCD. The imprecision of the sFLC analysis cannot fulfil the desirable performance standards for a laboratory test, but are within the manufacturer's ±20% variation for quality control samples. RI showed a significant increase for κ FLC and κ/λ ratio with age, but not for λ. Critical difference was calculated to be 24% and 23% for κ and λ, respectively. We suggest the use of an age-dependent RI. When monitoring patients with PCD, their own former results are the best reference, and knowledge on CD is a valuable tool, which we describe for the first time. Also, it challenges the recently proposed International Myeloma Working Group 'paraprotein relapse criteria', recommending an increase of more than 25% in the involved FLC to indicate the need for initiation of retreatment. We recommend revision of this criterion. © 2012 John Wiley & Sons A/S.

  8. Solvent effects in chemistry

    CERN Document Server

    Buncel, Erwin

    2015-01-01

    This book introduces the concepts, theory and experimental knowledge concerning solvent effects on the rate and equilibrium of chemical reactions of all kinds.  It begins with basic thermodynamics and kinetics, building on this foundation to demonstrate how a more detailed understanding of these effects may be used to aid in determination of reaction mechanisms, and to aid in planning syntheses. Consideration is given to theoretical calculations (quantum chemistry, molecular dynamics, etc.), to statistical methods (chemometrics), and to modern day concerns such as ""green"" chemistry, where ut

  9. Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rajput, Nav Nidhi; Murugesan, Vijayakumar; Shin, Yongwoo; Han, Kee Sung; Lau, Kah Chun; Chen, Junzheng; Liu, Jun; Curtiss, Larry A.; Mueller, Karl T.; Persson, Kristin A.

    2017-04-10

    Fundamental molecular level understanding of functional properties of liquid solutions provides an important basis for designing optimized electrolytes for numerous applica-tions. In particular, exhaustive knowledge of solvation structure, stability and transport properties is critical for developing stable electrolytes for fast charging and high energy density next-generation energy storage systems. Here we report the correlation between solubility, solvation structure and translational dynamics of a lithium salt (Li-TFSI) and polysulfides species using well-benchmarked classical molecular dynamics simulations combined with nuclear magnetic resonance (NMR). It is observed that the polysulfide chain length has a significant effect on the ion-ion and ion-solvent interaction as well as on the diffusion coefficient of the ionic species in solution. In particular, extensive cluster formation is observed in lower order poly-sulfides (Sx2-; x≤4), whereas the longer polysulfides (Sx2-; x>4) show high solubility and slow dynamics in the solu-tion. It is observed that optimal solvent/salt ratio is essen-tial to control the solubility and conductivity as the addi-tion of Li salt increases the solubility but decreases the mo-bility of the ionic species. This work provides a coupled theoretical and experimental study of bulk solvation struc-ture and transport properties of multi-component electro-lyte systems, yielding design metrics for developing optimal electrolytes with improved stability and solubility.

  10. Solvent effects in the synergistic solvent extraction of Co2+

    International Nuclear Information System (INIS)

    Kandil, A.T.; Ramadan, A.

    1979-01-01

    The extraction of Co 2+ from a 0.1M ionic strength aqueous phase (Na + , CH 3 COOH) of pH = 5.1 was studied using thenoyltrifluoroacetone, HTTA, in eight different solvents and HTTA + trioctylphosphine oxide, TOPO, in the same solvents. A comparison of the effect of solvent dielectric constant on the equilibrium constant shows a synergism as a result of the increased hydrophobic character imparted to the metal complex due to the formation of the TOPO adduct. (author)

  11. Optimizing critical source control of five priority-regulatory trace elements from industrial wastewater in China: Implications for health management.

    Science.gov (United States)

    Wu, Wenjun; Wang, Jinnan; Yu, Yang; Jiang, Hongqiang; Liu, Nianlei; Bi, Jun; Liu, Miaomiao

    2018-04-01

    Anthropogenic emissions of toxic trace elements (TEs) have caused worldwide concern due to their adverse effects on human health and ecosystems. Based on a stochastic simulation of factors' probability distribution, we established a bottom-up model to estimate the amounts of five priority-regulatory TEs released to aquatic environments from industrial processes in China. Total TE emissions in China in 2010 were estimated at approximately 2.27 t of Hg, 310.09 t of As, 318.17 t of Pb, 79.72 t of Cd, and 1040.32 t of Cr. Raw chemicals, smelting, and mining were the leading sources of TE emissions. There are apparent regional differences in TE pollution. TE emissions are much higher in eastern and central China than in the western provinces and are higher in the south than in the north. This spatial distribution was characterized in detail by allocating the emissions to 10 km × 10 km grid cells. Furthermore, the risk control for the overall emission grid was optimized according to each cell's emission and risk rank. The results show that to control 80% of TE emissions from major sources, the number of top-priority control cells would be between 200 and 400, and less than 10% of the total population would be positively affected. Based on TE risk rankings, decreasing the population weighted risk would increase the number of controlled cells by a factor of 0.3-0.5, but the affected population would increase by a factor of 0.8-1.5. In this case, the adverse effects on people's health would be reduced significantly. Finally, an optimized strategy to control TE emissions is proposed in terms of a cost-benefit trade-off. The estimates in this paper can be used to help establish a regional TE inventory and cyclic simulation, and it can also play supporting roles in minimizing TE health risks and maximizing resilience. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Solvent extraction of zirconium

    International Nuclear Information System (INIS)

    Kim, S.S.; Yoon, J.H.

    1981-01-01

    The extraction of zirconium(VI) from an aqueous solution of constant ionic strength with versatic acid-10 dissolved in benzen was studied as a function of pH and the concentration of zirconium(VI) and organic acid. The effects of sulphate and chlorine ions on the extraction of the zirconium(VI) were briefly examined. It was revealed that (ZrOR 2 .2RH) is the predominant species of extracted zirconium(VI) in the versatic acid-10. The chemical equation and the apparent equilibrium constants thereof have been determined as follows. (ZrOsup(2+))aq+ 2(R 2 H 2 )sub(org) = (ZrOR 2 .2RH)sub(org)+2(H + )aq Ksub(Zr) = (ZrOR 2 .2RH)sub(org)(H + ) 2 /(ZrOsup(2+))sub(aq)(R 2 H 2 )sup(2)sub(org) = 3.3 x 10 -7 . The synergistic effects of TBP and D2EHPA were also studied. In the mixed solvent with 0.1M TBP, the synergistic effect was observed, while the mixed solvent with D2EHPA showed the antisynergistic effect. (Author)

  13. Optimal analysis of gas cooler and intercooler for two-stage CO2 trans-critical refrigeration system

    International Nuclear Information System (INIS)

    Li, Wenhua

    2013-01-01

    Highlights: • Simplified model for tube-fin gas cooler for CO 2 refrigeration system was presented and validated. • Several parameters were investigated using 1st law and 2nd law in component and system level. • Practical guidelines of optimum for tube-fin gas cooler and intercooler were proposed. - Abstract: Energy-based 1st law and exergy-based 2nd law are both employed in the paper to assess the optimal design of gas cooler and intercooler for two-stage CO 2 refrigeration system. A simplified mathematical model of the air-cooled coil is presented and validated against experimental data with good accuracy. The optimum circuit length under the influence of frontal air velocity and deep rows is investigated first. Thereafter, designed coil with optimum circuit length is further evaluated within the two-stage refrigeration system. It is found out the optimum point using 1st law does not coincide with the point using 2nd law in isolated component and the simulation results from isolated component by 2nd law are closer to system analysis. Results show optimum circuit length is much bigger for gas cooler than intercooler and the influence on the length from variation of frontal air velocity and deep rows may be neglected. There does exist optimum frontal air velocity which will decrease with more number of deep rows

  14. Optimization of critical factors to enhance polyhydroxyalkanoates (PHA) synthesis by mixed culture using Taguchi design of experimental methodology.

    Science.gov (United States)

    Venkata Mohan, S; Venkateswar Reddy, M

    2013-01-01

    Optimizing different factors is crucial for enhancement of mixed culture bioplastics (polyhydroxyalkanoates (PHA)) production. Design of experimental (DOE) methodology using Taguchi orthogonal array (OA) was applied to evaluate the influence and specific function of eight important factors (iron, glucose concentration, VFA concentration, VFA composition, nitrogen concentration, phosphorous concentration, pH, and microenvironment) on the bioplastics production. Three levels of factor (2(1) × 3(7)) variation were considered with symbolic arrays of experimental matrix [L(18)-18 experimental trails]. All the factors were assigned with three levels except iron concentration (2(1)). Among all the factors, microenvironment influenced bioplastics production substantially (contributing 81%), followed by pH (11%) and glucose concentration (2.5%). Validation experiments were performed with the obtained optimum conditions which resulted in improved PHA production. Good substrate degradation (as COD) of 68% was registered during PHA production. Dehydrogenase and phosphatase enzymatic activities were monitored during process operation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Alternative solvents for post combustion carbon capture

    Energy Technology Data Exchange (ETDEWEB)

    Arachchige, Udara S.P.R. [Telemark University College, Porsgrunn (Norway); Melaaen, Morten C. [Telemark University College, Porsgrunn (Norway); Tel-Tek, Porsgrunn (Norway)

    2013-07-01

    The process model of post combustion chemical absorption is developed in Aspen Plus for both coal and gas fired power plant flue gas treating. The re-boiler energy requirement is considered as the most important factor to be optimized. Two types of solvents, mono-ethylamine (MEA) and di-ethylamine (DEA), are used to implement the model for three different efficiencies. The re-boiler energy requirement for regeneration process is calculated. Temperature and concentration profiles in absorption column are analyzed to understand the model behavior. Re-boiler energy requirement is considerably lower for DEA than MEA as well as impact of corrosion also less in DEA. Therefore, DEA can be recommended as a better solvent for post combustion process for carbon capture plants in fossil fuel fired power industries.

  16. Phase equilibria and thermodynamics of the Fe–Al–C system: Critical evaluation, experiment and thermodynamic optimization

    International Nuclear Information System (INIS)

    Phan, Anh Thu; Paek, Min-Kyu; Kang, Youn-Bae

    2014-01-01

    In order to provide an efficient tool to design alloy chemistry and processing conditions for high-strength, lightweight steel, an investigation of the Fe–Al–C ternary system was carried out by experimental phase diagram measurement and a CALPHAD thermodynamic analysis. Discrepancies between previously available experimental results and thermodynamic calculations were identified. The Fe–Al sub-binary system was re-optimized in order to obtain an accurate description of the liquid phase, while Gibbs energies of solid phases were mainly taken from a previous thermodynamic modeling. Phase equilibria among face-centered cubic (fcc)/body-centered cubic (bcc)/graphite/κ-carbide/liquid phases in the Fe–Al–C system in the temperature range from 1000 to 1400 °C were obtained by chemical equilibration followed by quenching, and subsequent composition analysis using electron probe microanalysis/inductively coupled plasma spectroscopy. By merging the revised Fe–Al binary description with existing Fe–C and Al–C binary descriptions, a complete thermodynamic description of the Fe–Al–C system was obtained in the present study. The modified quasi-chemical model in the pair approximation was used to model the liquid phase, while solid solutions were modeled using compound energy formalism. A2/B2 order/disorder transition in the bcc phase was taken into account. Compared with previously known experiments/thermodynamic modeling, a better agreement was obtained in the present study, regarding the stable region of fcc and the solidification thermal peak of a ternary alloy near the liquidus temperature. The obtained thermodynamic description also reproduced various types of experimental data in the Fe–Al–C system such as isothermal sections, vertical sections, liquidus projection, etc. The solidification of various steel grades was predicted and discussed

  17. Optimal strategies for VOC emission abatement produced by solvent evaporation. The Italian case study; Strategie ottimali per la riduzione delle emissioni di composti organici volatili da uso di solventi: il caso italiano

    Energy Technology Data Exchange (ETDEWEB)

    Vetrella, G.; Cirillo, M.C. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1998-07-01

    This work analyses technologies and costs of VOC (volatile organic compounds) abatement in the activities which belong to the solvent evaporation sector, and then it singles out the most successful strategies from the costs point of view to reduce the sector emissions on the base of fixed abatement objectives. The Italian case is discussed. [Italian] Il lavoro analizza tecnologie e costi di abbattimento dei COV (composti organici volatili) nel settore evaporazione solventi, e individua la strategia piu' efficace dal punto di vista dei costi per ridurre le emissioni del settore sulla base di prefissati obiettivi di abbattimento. Analizza la situazione italiana.

  18. Efficient Power Scheduling in Smart Homes Using Hybrid Grey Wolf Differential Evolution Optimization Technique with Real Time and Critical Peak Pricing Schemes

    Directory of Open Access Journals (Sweden)

    Muqaddas Naz

    2018-02-01

    Full Text Available With the emergence of automated environments, energy demand by consumers is increasing rapidly. More than 80% of total electricity is being consumed in the residential sector. This brings a challenging task of maintaining the balance between demand and generation of electric power. In order to meet such challenges, a traditional grid is renovated by integrating two-way communication between the consumer and generation unit. To reduce electricity cost and peak load demand, demand side management (DSM is modeled as an optimization problem, and the solution is obtained by applying meta-heuristic techniques with different pricing schemes. In this paper, an optimization technique, the hybrid gray wolf differential evolution (HGWDE, is proposed by merging enhanced differential evolution (EDE and gray wolf optimization (GWO scheme using real-time pricing (RTP and critical peak pricing (CPP. Load shifting is performed from on-peak hours to off-peak hours depending on the electricity cost defined by the utility. However, there is a trade-off between user comfort and cost. To validate the performance of the proposed algorithm, simulations have been carried out in MATLAB. Results illustrate that using RTP, the peak to average ratio (PAR is reduced to 53.02%, 29.02% and 26.55%, while the electricity bill is reduced to 12.81%, 12.012% and 12.95%, respectively, for the 15-, 30- and 60-min operational time interval (OTI. On the other hand, the PAR and electricity bill are reduced to 47.27%, 22.91%, 22% and 13.04%, 12%, 11.11% using the CPP tariff.

  19. Sharp Interface Tracking in Rotating Microflows of Solvent Extraction

    International Nuclear Information System (INIS)

    Glimm, James; Almeida, Valmor de; Jiao, Xiangmin; Sims, Brett

    2013-01-01

    The objective of this project is to develop a specialized sharp interface tracking simulation capability for predicting interaction of micron-sized drops and bubbles in rotating flows relevant to optimized design of contactor devices used in solvent extraction processes of spent nuclear fuel reprocessing. The primary outcomes of this project include the capability to resolve drops and bubbles micro-hydrodynamics in solvent extraction contactors, determining from first principles continuum fluid mechanics how micro-drops and bubbles interact with each other and the surrounding shearing fluid for realistic flows. In the near term, this effort will play a central role in providing parameters and insight into the flow dynamics of models that average over coarser scales, say at the millimeter unit length. In the longer term, it will prove to be the platform to conduct full-device, detailed simulations as parallel computing power reaches the exaflop level. The team will develop an accurate simulation tool for flows containing interacting droplets and bubbles with sharp interfaces under conditions that mimic those found in realistic contactor operations. The main objective is to create an off-line simulation capability to model drop and bubble interactions in a domain representative of the averaged length scale. The technical approach is to combine robust interface tracking software, subgrid modeling, validation quality experiments, powerful computational hardware, and a team with simulation modeling, physical modeling and technology integration experience. Simulations will then fully resolve the microflow of drops and bubbles at the microsecond time scale. This approach is computationally intensive but very accurate in treating important coupled physical phenomena in the vicinity of interfaces. The method makes it possible to resolve spatial scales smaller than the typical distance between bubbles and to model some non-equilibrium thermodynamic features such as finite

  20. Sharp Interface Tracking in Rotating Microflows of Solvent Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Glimm, James [Stony Brook Univ., NY (United States); Almeida, Valmor de [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jiao, Xiangmin [Stony Brook Univ., NY (United States); Sims, Brett [City Univ. (CUNY), NY (United States). Borough of Manhattan Community College; Li, Xaiolin [Stony Brook Univ., NY (United States)

    2013-01-08

    The objective of this project is to develop a specialized sharp interface tracking simulation capability for predicting interaction of micron-sized drops and bubbles in rotating flows relevant to optimized design of contactor devices used in solvent extraction processes of spent nuclear fuel reprocessing. The primary outcomes of this project include the capability to resolve drops and bubbles micro-hydrodynamics in solvent extraction contactors, determining from first principles continuum fluid mechanics how micro-drops and bubbles interact with each other and the surrounding shearing fluid for realistic flows. In the near term, this effort will play a central role in providing parameters and insight into the flow dynamics of models that average over coarser scales, say at the millimeter unit length. In the longer term, it will prove to be the platform to conduct full-device, detailed simulations as parallel computing power reaches the exaflop level. The team will develop an accurate simulation tool for flows containing interacting droplets and bubbles with sharp interfaces under conditions that mimic those found in realistic contactor operations. The main objective is to create an off-line simulation capability to model drop and bubble interactions in a domain representative of the averaged length scale. The technical approach is to combine robust interface tracking software, subgrid modeling, validation quality experiments, powerful computational hardware, and a team with simulation modeling, physical modeling and technology integration experience. Simulations will then fully resolve the microflow of drops and bubbles at the microsecond time scale. This approach is computationally intensive but very accurate in treating important coupled physical phenomena in the vicinity of interfaces. The method makes it possible to resolve spatial scales smaller than the typical distance between bubbles and to model some non-equilibrium thermodynamic features such as finite

  1. Selective solvent extraction of oils

    Energy Technology Data Exchange (ETDEWEB)

    1938-04-09

    In the selective solvent extraction of naphthenic base oils, the solvent used consists of the extract obtained by treating a paraffinic base oil with a selective solvent. The extract, or partially spent solvent is less selective than the solvent itself. Selective solvents specified for the extraction of the paraffinic base oil are phenol, sulphur dioxide, cresylic acid, nitrobenzene, B:B/sup 1/-dichlorethyl ether, furfural, nitroaniline and benzaldehyde. Oils treated are Coastal lubricating oils, or naphthenic oils from the cracking, or destructive hydrogenation of coal, tar, lignite, peat, shale, bitumen, or petroleum. The extraction may be effected by a batch or counter-current method, and in the presence of (1) liquefied propane, or butane, or naphtha, or (2) agents which modify the solvent power such as, water, ammonia, acetonitrile, glycerine, glycol, caustic soda or potash. Treatment (2) may form a post-treatment effected on the extract phase. In counter-current treatment in a tower some pure selective solvent may be introduced near the raffinate outlet to wash out any extract therefrom.

  2. Selection and design of solvents

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    and design of solvents will be presented together with application examples. The selection problem is defined as finding known chemicals that match the desired functions of a solvent for a specified set of applications. The design problem is defined as finding the molecular structure (or mixture of molecules....... With increasing interest on issues such as waste, sustainability, environmental impact and green chemistry, the selection and design of solvents have become important problems that need to be addressed during chemical product-process design and development. Systematic methods and tools suitable for selection......) that match the desired functions of a solvent for a specified set of applications. Use of organic chemicals and ionic liquids as solvents will be covered....

  3. Solvent extraction of Zn and metals in Zn ores by nonphosphorous solvents

    International Nuclear Information System (INIS)

    Auchapt, J.M.; Tostain, Jacqueline.

    1975-07-01

    This bibliography follows a first work on Zn solvent extraction by organo-phosphorous compounds. The other solvents used in Zn extraction, are studied: oxygenated nonphosphorous solvents (ketones, alcohols, carboxylic acids, sulfonates), nitrogenous solvents and hydrocarbons [fr

  4. Cesium Concentration in MCU Solvent

    International Nuclear Information System (INIS)

    Walker, D

    2006-01-01

    During Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) operations, Cs-137 concentrations in product streams will vary depending on the location in the process and on the recent process conditions. Calculations of cesium concentrations under a variety of operating conditions reveal the following: (1) Under nominal operations with salt solution feed containing 1.1 Ci Cs-137 per gallon, the maximum Cs-137 concentration in the process will occur in the strip effluent (SE) and equal 15-16.5 Ci/gal. (2) Under these conditions, the majority of the solvent will contain 0.005 to 0.01 Ci/gal, with a limited portion of the solvent in the contactor stages containing ∼4 Ci/gal. (3) When operating conditions yield product near 0.1 Ci Cs-137/gal in the decontaminated salt solution (DSS), the SE cesium concentration will be the same or lower than in nominal operations, but majority of the stripped solvent will increase to ∼2-3 Ci/gal. (4) Deviations in strip and waste stream flow rates cause the largest variations in cesium content: (a) If strip flow rates deviate by -30% of nominal, the SE will contain ∼23 Ci/gal, although the cesium content of the solvent will increase to only 0.03 Ci/gal; (b) If strip flow rate deviates by -77% (i.e., 23% of nominal), the SE will contain 54 Ci/gal and solvent will contain 1.65 Ci/gal. At this point, the product DSS will just reach the limit of 0.1 Ci/gal, causing the DSS gamma monitors to alarm; and (c) Moderate (+10 to +30%) deviations in waste flow rate cause approximately proportional increases in the SE and solvent cesium concentrations. Recovery from a process failure due to poor cesium stripping can achieve any low cesium concentration required. Passing the solvent back through the contactors while recycling DSS product will produce a ∼70% reduction during one pass through the contactors (assuming the stripping D value is no worse than 0.36). If the solvent is returned to the solvent hold tank (containing additional

  5. Maternal death inquiry and response in India - the impact of contextual factors on defining an optimal model to help meet critical maternal health policy objectives

    Directory of Open Access Journals (Sweden)

    Kalter Henry D

    2011-11-01

    Full Text Available Abstract Background Maternal death reviews have been utilized in several countries as a means of identifying social and health care quality issues affecting maternal survival. From 2005 to 2009, a standardized community-based maternal death inquiry and response initiative was implemented in eight Indian states with the aim of addressing critical maternal health policy objectives. However, state-specific contextual factors strongly influenced the effort's success. This paper examines the impact and implications of the contextual factors. Methods We identified community, public health systems and governance related contextual factors thought to affect the implementation, utilization and up-scaling of the death inquiry process. Then, according to selected indicators, we documented the contextual factors' presence and their impact on the process' success in helping meet critical maternal health policy objectives in four districts of Rajasthan, Madhya Pradesh and West Bengal. Based on this assessment, we propose an optimal model for conducting community-based maternal death inquiries in India and similar settings. Results The death inquiry process led to increases in maternal death notification and investigation whether civil society or government took charge of these tasks, stimulated sharing of the findings in multiple settings and contributed to the development of numerous evidence-based local, district and statewide maternal health interventions. NGO inputs were essential where communities, public health systems and governance were weak and boosted effectiveness in stronger settings. Public health systems participation was enabled by responsive and accountable governance. Communities participated most successfully through India's established local governance Panchayat Raj Institutions. In one instance this led to the development of a multi-faceted intervention well-integrated at multiple levels. Conclusions The impact of several contextual

  6. Processing of polymers using reactive solvents

    NARCIS (Netherlands)

    Lemstra, P.J.; Kurja, J.; Meijer, H.E.H.; Meijer, H.E.H.

    1997-01-01

    A review with many refs. on processing of polymers using reactive solvents including classification of synthetic polymers, guidelines for the selection of reactive solvents, basic aspects of processing, examples of intractable and tractable polymer/reactive solvent system

  7. Handbook of organic solvent properties

    CERN Document Server

    Smallwood, Ian

    2012-01-01

    The properties of 72 of the most commonly used solvents are given, tabulated in the most convenient way, making this book a joy for industrial chemists to use as a desk reference. The properties covered are those which answer the basic questions of: Will it do the job? Will it harm the user? Will it pollute the air? Is it easy to handle? Will it pollute the water? Can it be recovered or incinerated? These are all factors that need to be considered at the early stages of choosing a solvent for a new product or process.A collection of the physical properties of most commonly used solvents, their

  8. Acetone-based cellulose solvent.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; Heinze, Thomas

    2014-08-01

    Acetone containing tetraalkylammonium chloride is found to be an efficient solvent for cellulose. The addition of an amount of 10 mol% (based on acetone) of well-soluble salt triethyloctylammonium chloride (Et3 OctN Cl) adjusts the solvent's properties (increases the polarity) to promote cellulose dissolution. Cellulose solutions in acetone/Et3 OctN Cl have the lowest viscosity reported for comparable aprotic solutions making it a promising system for shaping processes and homogeneous chemical modification of the biopolymer. Recovery of the polymer and recycling of the solvent components can be easily achieved. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Production of thermostable and organic solvent-tolerant alkaline ...

    African Journals Online (AJOL)

    An alkaliphilic bacterium producing organic solvent-tolerant and thermostable alkaline protease was isolated from poultry litter site and identified as Bacillus coagulans PSB-07. Protease production under different submerged fermentation conditions were investigated with the aim of optimizing yield of enzyme. B. coagulans ...

  10. Critical tuning of magnetron sputtering process parameters for optimized solar selective absorption of NiCrO{sub x} cermet coatings on aluminium substrate

    Energy Technology Data Exchange (ETDEWEB)

    Gaouyat, Lucie, E-mail: lucie.gaouyat@fundp.ac.be [Solid State Physics Laboratory, Research Center in Physics of Matter and Radiation (PMR), Facultés Universitaires Notre-Dame de la Paix (FUNDP), 61 rue de Bruxelles, B-5000 Namur (Belgium); Mirabella, Frédéric [CRM Group – AC and CS, 57b boulevard de Colonster, B-4000 Liège (Belgium); Deparis, Olivier [Solid State Physics Laboratory, Research Center in Physics of Matter and Radiation (PMR), Facultés Universitaires Notre-Dame de la Paix (FUNDP), 61 rue de Bruxelles, B-5000 Namur (Belgium)

    2013-04-15

    NiCrO{sub x} ceramic–metal composites (i.e. cermets) exhibit not only oxidation and moisture resistances, which are very important for industrial applications, but also remarkable solar selective absorption properties. In order to reach the best optical performances with only one coating layer, tuning of the magnetron sputtering process parameters (O{sub 2} flow rate, pressure and deposition time) was performed systematically. The process window turned out to be very narrow implying a critical tuning of the parameters. The optimal operating point was determined for a single layer coating of NiCrO{sub x} on an aluminium substrate, leading to a spectrally integrated solar absorption as high as 78%. Among various material properties, the focus was put on the optical reflectance of the coating/substrate system, which was measured by UV–vis–NIR spectrophotometry. Using complex refractive index data from the literature, the theoretical reflectance spectra were calculated and found to be in good agreement with the measurements. Chemical analysis combined with scanning electronic and atomic force microscopies suggested a cermet structure consisting of metallic Ni particles and a compound matrix made of a mixture of chromium oxide, nickel oxide and nickel hydroxide.

  11. Uranium refining by solvent extraction

    International Nuclear Information System (INIS)

    Kraikaew, J.

    1996-01-01

    The yellow cake refining was studied in both laboratory and semi-pilot scales. The process units mainly consist of dissolution and filtration, solvent extraction, and precipitation and filtration. Effect of flow ratio (organic flow rate/ aqueous flow rate) on working efficiencies of solvent extraction process was studied. Detailed studies were carried out on extraction, scrubbing and stripping processes. Purity of yellow cake product obtained is high as 90.32% U 3 O 8

  12. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    Science.gov (United States)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  13. Effect of solvent composition on dispersing ability of reaction sialon suspensions.

    Science.gov (United States)

    Xu, Xin; Oliveira, Marta; Ferreira, José M F

    2003-03-15

    This work focuses on the optimization of the rheological behavior of suspensions considering different solvent compositions. The effects of methyl ethyl ketone (MEK)/ethanol (E) solvent mixtures on reaction sialon suspensions were investigated by measuring sedimentation behavior, adsorption of dispersant, and flow behavior. It was shown that both the flow behavior and the sedimentation behavior strongly depended on selection of solvent composition. Using 3 wt% KD1 as dispersant, well-dispersed colloidal suspensions could be obtained in MEK-rich solvents. The suspensions with 60 vol% MEK/40 vol% E as solvent could be fitted to the Bingham model with very low yield stress, while suspensions with pure MEK or ethanol-rich mixtures as solvent showed pseudo plastic behavior with relatively high yield stress values. A model was proposed to explain the different flow behaviors of suspensions considering the different configurations of dispersant at particles' surfaces.

  14. LIGHT Is critical for IL-12 production by dendritic cells, optimal CD4+ Th1 cell response, and resistance to Leishmania major.

    Science.gov (United States)

    Xu, Guilian; Liu, Dong; Okwor, Ifeoma; Wang, Yang; Korner, Heinrich; Kung, Sam K P; Fu, Yang-Xin; Uzonna, Jude E

    2007-11-15

    Although studies indicate LIGHT (lymphotoxin (LT)-like, exhibits inducible expression and competes with HSV glycoprotein D for herpes virus entry mediator (HVEM), a receptor expressed by T lymphocytes) enhances inflammation and T cell-mediated immunity, the mechanisms involved in this process remain obscure. In this study, we assessed the role of LIGHT in IL-12 production and development of CD4(+) Th cells type one (Th1) in vivo. Bone marrow-derived dendritic cells from LIGHT(-/-) mice were severely impaired in IL-12p40 production following IFN-gamma and LPS stimulation in vitro. Furthermore, blockade of LIGHT in vitro and in vivo with HVEM-Ig and LT beta receptor (LTbetaR)-Ig leads to impaired IL-12 production and defective polyclonal and Ag-specific IFN-gamma production in vivo. In an infection model, injection of HVEM-Ig or LTbetaR-Ig into the usually resistant C57BL/6 mice results in defective IL-12 and IFN-gamma production and severe susceptibility to Leishmania major that was reversed by rIL-12 treatment. This striking susceptibility to L. major in mice injected with HVEM-Ig or LTbetaR-Ig was also reproduced in LIGHT(-/-) --> RAG1(-/-) chimeric mice. In contrast, L. major-infected LTbeta(-/-) mice do not develop acute disease, suggesting that the effect of LTbetaR-Ig is not due to blockade of membrane LT (LTalpha1beta2) signaling. Collectively, our data show that LIGHT plays a critical role for optimal IL-12 production by DC and the development of IFN-gamma-producing CD4(+) Th1 cells and its blockade results in severe susceptibility to Leishmania major.

  15. Optimization of the rheological properties of epoxy resins for glass and carbon reinforced plastics

    Science.gov (United States)

    Phyo Maung, Pyi; Malysheva, G.; Romanova, I.

    2016-10-01

    Vacuum assisted resin transfer moulding (VARTM) offers advantages such as simplicity, low cost of consumables, and the ability to carry out the impregnation process and curing without using expensive equipment and tooling. In the VARTM process, rheological properties of resin have a critical impact on the impregnation and curing process. In this article, the experimental results of viscosity are presented, including the glass transition temperature, and the tensile and bending strength of the epoxy binders with the amine hardener, which depend on the quantity of its active solvent composition. The active solvent used is diethylene glycol. It shows that for an increase in the content of the active solvent, a reduction in the viscosity and a reduction of the glass transition temperature and strength occurs. The optimum composition of the binder is selected by using the Pareto optimization criteria and the Cayley - Smorodinskaya method. By using the epoxy binder, the active solvent should not exceed 10-15% by weight. This approach helps to optimize the amount of active solvent added to the epoxy resins for the criterion of viscosity, strength, and heat resistance.

  16. A novel technique to determine concentration-dependent solvent dispersion in Vapex

    Energy Technology Data Exchange (ETDEWEB)

    Abukhalifeh, H.; Lohi, A.; Upreti, S. R. [Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario, M5B 2K3 (Canada)

    2009-07-01

    Vapex (vapor extraction of heavy oil and bitumen) is a promising recovery technology because it consumes low energy, and is very environmentally-friendly. The dispersion of solvents into heavy oil and bitumen is a crucial transport property governing Vapex. The accurate determination of solvent dispersion in Vapex is essential to effectively predict the amount and time scale of oil recovery as well to optimize the field operations. In this work, a novel technique is developed to experimentally determine the concentration-dependent dispersion coefficient of a solvent in Vapex process. The principles of variational calculus are utilized in conjunction with a mass transfer model of the experimental Vapex process. A computational algorithm is developed to optimally compute solvent dispersion as a function of its concentration in heavy oil. The developed technique is applied to Vapex utilizing propane as a solvent. The results show that dispersion of propane is a unimodal function of its concentration in bitumen. (author)

  17. A Novel Technique to Determine Concentration-Dependent Solvent Dispersion in Vapex

    Directory of Open Access Journals (Sweden)

    Hadil Abukhalifeh

    2009-10-01

    Full Text Available Vapex (vapor extraction of heavy oil and bitumen is a promising recovery technology because it consumes low energy, and is very environmentally-friendly. The dispersion of solvents into heavy oil and bitumen is a crucial transport property governing Vapex. The accurate determination of solvent dispersion in Vapex is essential to effectively predict the amount and time scale of oil recovery as well to optimize the field operations. In this work, a novel technique is developed to experimentally determine the concentration-dependent dispersion coefficient of a solvent in Vapex process. The principles of variational calculus are utilized in conjunction with a mass transfer model of the experimental Vapex process. A computational algorithm is developed to optimally compute solvent dispersion as a function of its concentration in heavy oil. The developed technique is applied to Vapex utilizing propane as a solvent. The results show that dispersion of propane is a unimodal function of its concentration in bitumen.

  18. Solvents interactions with thermochromic print

    Directory of Open Access Journals (Sweden)

    Mirela Rožić

    2017-12-01

    Full Text Available In this study, the interactions between different solvents (benzene, acetone, cyclohexanone, various alcohols and water and thermochromic printing ink were investigated. Thermochromic printing ink was printed on metal surface. Components of thermochromic printing inks are polymeric microcapsules and classic yellow offset printing ink. Below its activation temperature, dye and developer within the microcapsules form a blue coloured complex. Therefore, thermochromic print is green. By heating above the activation temperature, blue colour of the complex turns into the leuco dye colourless state and the green colour of the prints turns into the yellow colour of the classic offset pigment. The results of the interaction with various solvents show that the thermochromic print is stable in all tested solvents except in ethanol, acetone and cyclohexanone. In ethanol, the green colour of the print becomes yellow. SEM analysis shows that microcapsules are dissolved. In acetone and cyclohexanone, the green colour of the print turns into blue, and the microcapsules become significantly more visible. Thus, the yellow pigment interacts with examined ketones. Based on the obtained interactions it can be concluded that the microcapsules have more polar nature than the classical pigment particles. Solvent-thermocromic print interactions were analysed using Hansen solubility parameters that rank the solvents based on their estimated interaction capabilities.

  19. Hydrogenation of Isophthalonitrile with 1-Methylimidazole as an Effective Solvent for m-Xylenediamine Production

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Tae Young; Row, Sung Wook; Yoo, Kye Sang; Lee, Sang Duek [Environment and Process Technology Division, Seoul (Korea, Republic of); Lee, Do Weon [University of Seoul, Seoul (Korea, Republic of)

    2006-03-15

    1-methylimidazole was shown to outperform the other organic solvents in this reaction. Moreover, amount of ammonia with using 1-methylimidazole as a solvent was lower than other processes. Thus, 1-methylimidazole is an attractive solvent in IPN hydrogenation for the production of MXDA. The correct choice of a solvent is a critical factor to govern the catalytic activity with desirable hydrogenation. Conventionally, organic materials such as aromatic hydrocarbons, aliphatic alcohols, aliphatic hydrocarbons, dimethylformamide and dioxane were employed in this reaction. Several MXDA producing processes with the organic solvent including m-xylene, pseudocumene, mesitylene, ethylbenzene, methylpyridine, benzonitrile, m-tolunitrile, MXDA and cyanopyridine were disclosed. However, the solvents and ammonia were vaporized under the operation conditions leading to amine cleavage with the resulting formation of methylbenzyl amines or the consumption of ammonia was still significant. Recently, some researchers reported that a high yield of MXDA was achieved using isopropanol under relatively low pressure condition; however, the consumption of ammonia was very significant.

  20. Bioremediation potential of a newly isolate solvent tolerant strain Bacillus thermophilus PS11

    Directory of Open Access Journals (Sweden)

    PAYEL SARKAR

    2012-01-01

    Full Text Available The increased generation of solvent waste has been stated as one of the most critical environmental problems. Though microbial bioremediation has been widely used for waste treatment but their application in solvent waste treatment is limited since the solvents have toxic effects on the microbial cells. A solvent tolerant strain of Bacillus thermophilus PS11 was isolated from soil by cyclohexane enrichment. Transmission electron micrograph of PS11 showed convoluted cell membrane and accumulation of solvents in the cytoplasm, indicating the adaptation of the bacterial strain to the solvent after 48h of incubation. The strain was also capable of growing in presence of wide range of other hydrophobic solvents with log P-values below 3.5. The isolate could uptake 50 ng/ml of uranium in its initial 12h of growth, exhibiting both solvent tolerance and metal resistance property. This combination of solvent tolerance and metal resistance will make the isolated Bacillus thermophilus PS11 a potential tool for metal bioremediation in solvent rich wastewaters.

  1. Multiple sclerosis and organic solvents

    DEFF Research Database (Denmark)

    Mortensen, J T; Brønnum-Hansen, Henrik; Rasmussen, K

    1998-01-01

    We investigated a possible causal relation between exposure to organic solvents in Danish workers (housepainters, typographers/printers, carpenters/cabinetmakers) and onset of multiple sclerosis. Data on men included in the Danish Multiple Sclerosis Register (3,241 men) were linked with data from......, and butchers. Over a follow-up period of 20 years, we observed no increase in the incidence of multiple sclerosis among men presumed to be exposed to organic solvents. It was not possible to obtain data on potential confounders, and the study design has some potential for selection bias. Nevertheless......, the study does not support existing hypotheses regarding an association between occupational exposure to organic solvents and multiple sclerosis....

  2. Indium recovery by solvent extraction

    International Nuclear Information System (INIS)

    Fortes, Marilia Camargos Botelho

    1999-04-01

    Indium has been recovered as a byproduct from residues generated from the sulfuric acid leaching circuits in mineral plants for zinc recovery. Once its recovery comes from the slags of other metals recovery, it is necessary to separate it from the other elements which usually are present in high concentrations. Many works have been approaching this separation and indicate the solvent extraction process as the main technique used. In Brazilian case, indium recovery depends on the knowledge of this technique and its development. This paper describes the solvent extraction knowledge for the indium recovery from aqueous solutions generated in mineral plants. The results for determination of the best experimental conditions to obtain a high indium concentration solution and minimum iron poisoning by solvent extraction with di (2-ethylhexyl)-phosphoric acid (D2EHPA) solubilized in isoparafin and exxsol has been presented. (author)

  3. Solvent sorting in (mixed solvent electrolyte) systems: Time-resolved ...

    Indian Academy of Sciences (India)

    lar solvents as an effective single component dipo- lar liquid that is characterized ... and time (t) dependent solvation energy of mobile dipo- lar solute with density ..... Even though this way for modification of C is purely ad- hoc, the observation ...

  4. Solvent extraction of gold using ionic liquid based process

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Zunita, Megawati; Rizki, Z.; Dharmawijaya, P. T.

    2017-01-01

    In decades, many research and mineral processing industries are using solvent extraction technology for metal ions separation. Solvent extraction technique has been used for the purification of precious metals such as Au and Pd, and base metals such as Cu, Zn and Cd. This process uses organic compounds as solvent. Organic solvents have some undesired properties i.e. toxic, volatile, excessive used, flammable, difficult to recycle, low reusability, low Au recovery, together with the problems related to the disposal of spent extractants and diluents, even the costs associated with these processes are relatively expensive. Therefore, a lot of research have boosted into the development of safe and environmentally friendly process for Au separation. Ionic liquids (ILs) are the potential alternative for gold extraction because they possess several desirable properties, such as a the ability to expanse temperature process up to 300°C, good solvent properties for a wide range of metal ions, high selectivity, low vapor pressures, stability up to 200°C, easy preparation, environmentally friendly (commonly called as "green solvent"), and relatively low cost. This review paper is focused in investigate of some ILs that have the potentials as solvent in extraction of Au from mineral/metal alloy at various conditions (pH, temperature, and pressure). Performances of ILs extraction of Au are studied in depth, i.e. structural relationship of ILs with capability to separate Au from metal ions aggregate. Optimal extraction conditon in order to gain high percent of Au in mineral processing is also investigated.

  5. Solvents effects on crystallinity and dissolution of β-artemether.

    Science.gov (United States)

    Xu, Jianghui; Singh, Vikramjeet; Yin, Xianzhen; Singh, Parbeen; Wu, Li; Xu, Xiaonan; Guo, Tao; Sun, Lixin; Gui, Shuangying; Zhang, Jiwen

    2017-03-01

    β-artemether (ARM) is a widely used anti-malarial drug isolated from the Chinese antimalarial plant, Artemisia annua. The solvent effects on crystal habits and dissolution of ARM were thoroughly investigated and discussed herein. The ARM was recrystallized in nine different solvents of varied polarity, namely, methanol, ethanol, isopropanol, tetrahydrofuran, dichloromethane, trichloromethane, ethyl acetate, acetone and hexane by solvent evaporation method. The obtained crystals were morphologically characterized using scanning electron microscope (SEM). The average sizes of crystals were 1.80-2.64 μm calculated from microscopic images using Image-Pro software. No significant change in chemical structure was noticed after recrystallization and the specific band at 875 cm -1 wavenumber (C-O-O-C) confirmed the presence of most sensitive functional group in the ARM chemical structure. The existence and production of two polymorphic forms, polymorph A and polymorph B, was confirmed by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). The data suggested that the fabrication of polymorph B can be simply obtained from the recrystallization of ARM in a specific solvent. Significant effects of solvent polarity, crystals shapes and sizes on drug dissolution were noticed during in vitro dissolution test. The release kinetics were calculated and well fitted by the Higuchi and Hixon-Crowell models. The ARM-methanol and ARM-hexane showed highest and slowest dissolution, respectively, due to the effects of solvent polarity and crystal morphologies. Overall, proper selection of the solvents for the final crystallization of ARM helps to optimize dissolution and bioavailability for a better delivery of anti-malarial drug.

  6. Field demonstration of foam injection to confine a chlorinated solvent source zone.

    Science.gov (United States)

    Portois, Clément; Essouayed, Elyess; Annable, Michael D; Guiserix, Nathalie; Joubert, Antoine; Atteia, Olivier

    2018-05-01

    A novel approach using foam to manage hazardous waste was successfully demonstrated under active site conditions. The purpose of the foam was to divert groundwater flow, that would normally enter the source zone area, to reduce dissolved contaminant release to the aquifer. During the demonstration, foam was pre generated and directly injected surrounding the chlorinated solvent source zone. Despite the constraints related to the industrial activities and non-optimal position of the injection points, the applicability and effectiveness of the approach have been highlighted using multiple metrics. A combination of measurements and modelling allowed definition of the foam extent surrounding each injection point, and this appears to be the critical metric to define the success of the foam injection approach. Information on the transport of chlorinated solvents in groundwater showed a decrease of contaminant flux by a factor of 4.4 downstream of the confined area. The effective permeability reduction was maintained over a period of three months. The successful containment provides evidence for consideration of the use of foam to improve traditional flushing techniques, by increasing the targeting of contaminants by remedial agents. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. A multi target approach to control chemical reactions in their inhomogeneous solvent environment

    International Nuclear Information System (INIS)

    Keefer, Daniel; Thallmair, Sebastian; Zauleck, Julius P P; Vivie-Riedle, Regina de

    2015-01-01

    Shaped laser pulses offer a powerful tool to manipulate molecular quantum systems. Their application to chemical reactions in solution is a promising concept to redesign chemical synthesis. Along this road, theoretical developments to include the solvent surrounding are necessary. An appropriate theoretical treatment is helpful to understand the underlying mechanisms. In our approach we simulate the solvent by randomly selected snapshots from molecular dynamics trajectories. We use multi target optimal control theory to optimize pulses for the various arrangements of explicit solvent molecules simultaneously. This constitutes a major challenge for the control algorithm, as the solvent configurations introduce a large inhomogeneity to the potential surfaces. We investigate how the algorithm handles the new challenges and how well the controllability of the system is preserved with increasing complexity. Additionally, we introduce a way to statistically estimate the efficiency of the optimized laser pulses in the complete thermodynamical ensemble. (paper)

  8. Improved Purex solvent scrubbing methods

    International Nuclear Information System (INIS)

    Mailen, J.C.; Tallent, O.K.

    1984-01-01

    Studies of hydrazine and hydroxylamine salts as solvent scrubbing agents that can be decomposed into gases are summarized. Results from testing of countercurrent scrubbers and solid sorber columns that produce lesser amounts of permanent salts are reported. The status of studies of the acid-degradation of paraffin diluent and the options for removal of long-chain organic acids is given

  9. Risk assessment for halogenated solvents

    International Nuclear Information System (INIS)

    Travis, C.C.

    1988-01-01

    A recent development in the cancer risk area is the advent of biologically based pharmacokinetic and pharmacodynamic models. These models allow for the incorporation of biological and mechanistic data into the risk assessment process. These advances will not only improve the risk assessment process for halogenated solvents but will stimulate and guide basic research in the biological area

  10. High throughput research and evaporation rate modeling for solvent screening for ethylcellulose barrier membranes in pharmaceutical applications.

    Science.gov (United States)

    Schoener, Cody A; Curtis-Fisk, Jaime L; Rogers, True L; Tate, Michael P

    2016-10-01

    Ethylcellulose is commonly dissolved in a solvent or formed into an aqueous dispersion and sprayed onto various dosage forms to form a barrier membrane to provide controlled release in pharmaceutical formulations. Due to the variety of solvents utilized in the pharmaceutical industry and the importance solvent can play on film formation and film strength it is critical to understand how solvent can influence these parameters. To systematically study a variety of solvent blends and how these solvent blends influence ethylcellulose film formation, physical and mechanical film properties and solution properties such as clarity and viscosity. Using high throughput capabilities and evaporation rate modeling, thirty-one different solvent blends composed of ethanol, isopropanol, acetone, methanol, and/or water were formulated, analyzed for viscosity and clarity, and narrowed down to four solvent blends. Brookfield viscosity, film casting, mechanical film testing and water permeation were also completed. High throughput analysis identified isopropanol/water, ethanol, ethanol/water and methanol/acetone/water as solvent blends with unique clarity and viscosity values. Evaporation rate modeling further rank ordered these candidates from excellent to poor interaction with ethylcellulose. Isopropanol/water was identified as the most suitable solvent blend for ethylcellulose due to azeotrope formation during evaporation, which resulted in a solvent-rich phase allowing the ethylcellulose polymer chains to remain maximally extended during film formation. Consequently, the highest clarity and most ductile films were formed. Employing high throughput capabilities paired with evaporation rate modeling allowed strong predictions between solvent interaction with ethylcellulose and mechanical film properties.

  11. Optimal Bidding and Operation of a Power Plant with Solvent-Based Carbon Capture under a CO2 Allowance Market: A Solution with a Reinforcement Learning-Based Sarsa Temporal-Difference Algorithm

    Directory of Open Access Journals (Sweden)

    Ziang Li

    2017-04-01

    Full Text Available In this paper, a reinforcement learning (RL-based Sarsa temporal-difference (TD algorithm is applied to search for a unified bidding and operation strategy for a coal-fired power plant with monoethanolamine (MEA-based post-combustion carbon capture under different carbon dioxide (CO2 allowance market conditions. The objective of the decision maker for the power plant is to maximize the discounted cumulative profit during the power plant lifetime. Two constraints are considered for the objective formulation. Firstly, the tradeoff between the energy-intensive carbon capture and the electricity generation should be made under presumed fixed fuel consumption. Secondly, the CO2 allowances purchased from the CO2 allowance market should be approximately equal to the quantity of CO2 emission from power generation. Three case studies are demonstrated thereafter. In the first case, we show the convergence of the Sarsa TD algorithm and find a deterministic optimal bidding and operation strategy. In the second case, compared with the independently designed operation and bidding strategies discussed in most of the relevant literature, the Sarsa TD-based unified bidding and operation strategy with time-varying flexible market-oriented CO2 capture levels is demonstrated to help the power plant decision maker gain a higher discounted cumulative profit. In the third case, a competitor operating another power plant identical to the preceding plant is considered under the same CO2 allowance market. The competitor also has carbon capture facilities but applies a different strategy to earn profits. The discounted cumulative profits of the two power plants are then compared, thus exhibiting the competitiveness of the power plant that is using the unified bidding and operation strategy explored by the Sarsa TD algorithm.

  12. Liquid Salt as Green Solvent: A Novel Eco-Friendly Technique to Enhance Solubility and Stability of Poorly Soluble Drugs

    Science.gov (United States)

    Patel, Anant A.

    As a result of tremendous efforts in past few decades, various techniques have been developed in order to resolve solubility issues associated with class II and IV drugs, However, majority of these techniques offer benefits associated with certain drawbacks; majorly including low drug loading, physical instability on storage and excessive use of environmentally challenging organic solvents. Hence, current effort was to develop an eco-friendly technique using liquid salt as green solvent, which can offer improvement in dissolution while maintaining long term stability. The liquid salt formulations (LSF) of poorly soluble model drugs ibuprofen, gemfibrozil and indomethacin were developed using 1-Ethyl-3-methylimidazolium ethyl sulfate (EMIM ES) as a non-toxic and environmentally friendly alternate to organic solvents. Liquid medications containing clear solutions of drug, EMIM ES and polysorbate 20, were adsorbed onto porous carrier Neusilin US2 to form free flowing powder. The LSF demonstrated greater rate and extent of dissolution compared to crystalline drugs. The dissolution data revealed that more than 80% drug release from LSF within 20 mins compared to less than 18% release from pure drugs. As high as 70% w/w liquid loading was achieved while maintaining good flowability and compressibility. In addition, the LSF samples exposed to high temperature and high humidity i.e. 40°C/80% RH for 8 weeks, demonstrated excellent physical stability without any signs of precipitation or crystallization. As most desirable form of administration is tablet, the developed liquid salt formulations were transformed into tablets using design of experiment approach by Design Expert Software. The tablet formulation composition and critical parameter were optimized using Box-Behnken Design. This innovative liquid salt formulation technique offered improvement in dissolution rate and extent as well as contributed to excellent physical stability on storage. Moreover, this formulation

  13. Understanding Solvent Manipulation of Morphology in Bulk-Heterojunction Organic Solar Cells.

    Science.gov (United States)

    Chen, Yuxia; Zhan, Chuanlang; Yao, Jiannian

    2016-10-06

    Film morphology greatly influences the performance of bulk-heterojunction (BHJ)-structure-based solar cells. It is known that an interpenetrating bicontinuous network with nanoscale-separated donor and acceptor phases for charge transfer, an ordered molecular packing for exciton diffusion and charge transport, and a vertical compositionally graded structure for charge collection are prerequisites for achieving highly efficient BHJ organic solar cells (OSCs). Therefore, control of the morphology to obtain an ideal structure is a key problem. For this solution-processing BHJ system, the solvent participates fully in film processing. Its involvement is critical in modifying the nanostructure of BHJ films. In this review, we discuss the effects of solvent-related methods on the morphology of BHJ films, including selection of the casting solvent, solvent mixture, solvent vapor annealing, and solvent soaking. On the basis of a discussion on interaction strength and time between solvent and active materials, we believe that the solvent-morphology-performance relationship will be clearer and that solvent selection as a means to manipulate the morphology of BHJ films will be more rational. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Iodine removing method in organic solvent

    International Nuclear Information System (INIS)

    Suzuki, Takeo; Sakurai, Manabu

    1988-01-01

    Purpose: To effectively remove iodine in an organic solvent to thereby remove iodine in the solvent that can be re-used or put to purning treatment. Method: Organic solvent formed from wastes of nuclear facilities is mixed with basic lead acetate, or silica gel or activated carbon incorporated with such a compound to adsorb iodine in the organic solvent to the basic lead acetate. Then, iodine in the organic solvent is removed by separating to eliminate the basic lead acetate adsorbing iodine from the organic solvent or by passing the organic solvent through a tower or column charged or pre-coated with silica gel or activated carbon incorporated with lead acetate. By using basic lead acetate as the adsorbents, iodine can effective by adsorbed and eliminated. Thus, the possibility of circumstantial release of iodine can be reduced upon reusing or burning treatment of the organic solvent. (Kamimura, M.)

  15. Computer Aided Solvent Selection and Design Framework

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Conte, Elisa; Abildskov, Jens

    and computer-aided tools and methods for property prediction and computer-aided molecular design (CAMD) principles. This framework is applicable for solvent selection and design in product design as well as process design. The first module of the framework is dedicated to the solvent selection and design...... in terms of: physical and chemical properties (solvent-pure properties); Environment, Health and Safety (EHS) characteristic (solvent-EHS properties); operational properties (solvent–solute properties). 3. Performing the search. The search step consists of two stages. The first is a generation and property...... identification of solvent candidates using special software ProCAMD and ProPred, which are the implementations of computer-aided molecular techniques. The second consists of assigning the RS-indices following the reaction–solvent and then consulting the known solvent database and identifying the set of solvents...

  16. Canyon solvent cleaning with solid adsorbents

    International Nuclear Information System (INIS)

    Reif, D.J.

    1987-01-01

    The HM Process at the Savannah River Plant (SRP) uses 7.5% tributyl phosphate in n-paraffin as an extraction solvent. During use, the solvent is altered due to hydrolysis and radiolysis, forming materials that influence product losses, product decontamination, and separation efficiencies. Laboratory studies to improve online solvent cleaning have shown that carbonate washing, although removing residual solvent activity, does not remove binding ligands that hold fission products in the solvent. Treatment of solvent with a solid adsorbent removes binding ligands and significantly improves recycle solvent performance. Both laboratory work defining a full-scale adsorption process and the use of the process to clean HM Process first cycle solvent are presented

  17. CriticalEd

    DEFF Research Database (Denmark)

    Kjellberg, Caspar Mølholt; Meredith, David

    2014-01-01

    . Since the comments are not input sequentially, with regard to position, but in arbitrary order, this list must be sorted by copy/pasting the rows into place—an error-prone and time-consuming process. Scholars who produce critical editions typically use off-the-shelf music notation software......The best text method is commonly applied among music scholars engaged in producing critical editions. In this method, a comment list is compiled, consisting of variant readings and editorial emendations. This list is maintained by inserting the comments into a document as the changes are made......, consisting of a Sibelius plug-in, a cross-platform application, called CriticalEd, and a REST-based solution, which handles data storage/retrieval. A prototype has been tested at the Danish Centre for Music Publication, and the results suggest that the system could greatly improve the efficiency...

  18. Recent solvent extraction experience at Savannah River

    International Nuclear Information System (INIS)

    Gray, L.W.; Burney, G.A.; Gray, J.H.; Hodges, M.E.; Holt, D.L.; Macafee, I.M.; Reif, D.J.; Shook, H.E.

    1986-01-01

    Tributyl phosphate-based solvent extraction processes have been used at Savannah River for more than 30 years to separate and purify thorium, uranium, neptunium, plutonium, americium, and curium isotopes. This report summarizes the advancement of solvent extraction technology at Savannah River during the 1980's. Topics that are discussed include equipment improvements, solvent treatment, waste reduction, and an improved understanding of the various chemistries in the process streams entering, within, and leaving the solvent extraction processes

  19. Solvent extraction studies of RERTR silicide fuels

    International Nuclear Information System (INIS)

    Gouge, Anthony P.

    1983-01-01

    Uranium silicide fuels, which are candidate RERTR fuel compositions, may require special considerations in solvent extraction reprocessing. Since Savannah River Plant may be reprocessing RERTR fuels as early as 1985, studies have been conducted at Savannah River Laboratory to demonstrate the solvent extraction behavior of this fuel. Results of solvent extraction studies with both unirradiated and irradiated fuel are presented along with the preliminary RERTR solvent extraction reprocessing flow sheet for Savannah River Plant. (author)

  20. Restoring solvent for nuclear separation processes

    International Nuclear Information System (INIS)

    Reif, D.J.

    1987-01-01

    Solvent extraction separation processes are used to recover usable nuclear materials from spent fuels. These processes involve the use of an extractant/diluent (solvent) for separation of the reusable actinides from unwanted fission products. The most widely used processes employ tributyl phosphate as an extractant diluted with a normal-paraffin hydrocarbon. During use, the solvent is altered due to hydrolysis and radiolysis, forming materials that influence product losses, product decontamination, and separation efficiencies. In most processes, the solvent is recycled after cleaning. Solvent cleaning generally involves scrubbing with a sodium carbonate solution. Studies at the Savannah River Laboratory have shown that carbonate washing, although removing residual solvent activity, does not remove more solvent-soluble binding ligands (formed by solvent degradation), which hold fission products in the solvent. Treatment of the solvent with a solid adsorbent after carbonate washing removes binding ligands and significantly improves recycled solvent performance. Laboratory work to establish the advantage of adsorbent cleaning and the development of a full-scale adsorption process is described. The application of this process for cleaning the first cycle solvent of a Savannah River Plant production process is discussed

  1. Solvent Extraction of Furfural From Biomass

    Science.gov (United States)

    Humphrey, M. F.

    1984-01-01

    Solvent-extraction method reduces energy required to remove furfural produced during acid hydrolysis of biomass. Acid hydrolysis performed in vessel containing both solvents and reacting ingredients. With intimate contact between solvents and aqueous hydrolyis liqour, furfural removed form liquor almost as fast as it forms.

  2. Adaptive Resolution Simulation of MARTINI Solvents

    NARCIS (Netherlands)

    Zavadlav, Julija; Melo, Manuel N.; Cunha, Ana V.; de Vries, Alex H.; Marrink, Siewert J.; Praprotnik, Matej

    We present adaptive resolution dynamics simulations of aqueous and apolar solvents coarse-grained molecular models that are compatible with the MARTINI force field. As representatives of both classes solvents we have chosen liquid water and butane, respectively, at ambient temperature. The solvent

  3. Experimental determination of the LLE data of systems consisting of {hexane + benzene + deep eutectic solvent} and prediction using the Conductor-like Screening Model for Real Solvents

    NARCIS (Netherlands)

    Rodriguez Rodriguez, Nerea; Gerlach, T.; Scheepers, Daniëlle; Kroon, M.C.; Smirnova, I.

    2017-01-01

    Recently, deep eutectic solvents (DESs) have proven to be excellent extracting agents in the separation of aromatic components from their mixtures with aliphatic compounds. The tunable properties of the DESs allow to tailor-make optimal solvents for this application. In this work type III DESs,

  4. Anti-solvent co-crystallization of carbamazepine and saccharin.

    Science.gov (United States)

    Wang, In-Chun; Lee, Min-Jeong; Sim, Sang-Jun; Kim, Woo-Sik; Chun, Nan-Hee; Choi, Guang J

    2013-06-25

    The co-crystal approach has been investigated extensively over the past decade as one of the most promising methods to enhance the dissolution properties of insoluble drug substances. Co-crystal powders are typically produced by mechanical grinding (neat or wet) or a solution method (evaporation or cooling). In this study, high-purity carbamazepine-saccharin (CBZ-SAC) co-crystals were manufactured by a novel method, anti-solvent addition. Among various solvents, methanol was found to perform well with water as the anti-solvent for the co-crystallization of CBZ and SAC. When water was added to the methanol solution of CBZ and SAC at room temperature under agitation, nucleation of CBZ-SAC co-crystals occurred within 2-3 min. Co-crystallization was complete after 30 min, giving a solid yield as high as 84.5% on a CBZ basis. The effects of initial concentrations, focusing on the SAC/CBZ ratio, were examined to establish optimal conditions. The whole anti-solvent co-crystallization process was monitored at-line via ATR-FTIR analysis of regularly sampled solutions. The nucleation and crystal growth of CBZ-SAC co-crystals were detected by a significant increase in absorption in the range of 2400-2260 cm(-1), associated with the formation of hydrogen bonds between the carbonyl group in CBZ and the N-H of SAC. When CBZ hydrates were formed as impurities during anti-solvent co-crystallization, the hydrogen bonding between methanol and water was reduced greatly, primarily due to the incorporation of water molecules into the CBZ crystal lattice. In conclusion, an anti-solvent approach can be used to produce highly pure CBZ-SAC co-crystal powders with a high solid yield. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Versatile Production of Poly(Epsilon-Caprolactone Fibers by Electrospinning Using Benign Solvents

    Directory of Open Access Journals (Sweden)

    Liliana Liverani

    2016-04-01

    Full Text Available The electrospinning technique is widely used for the fabrication of micro- and nanofibrous structures. Recent studies have focused on the use of less toxic and harmful solvents (benign solvents for electrospinning, even if those solvents usually require an accurate and longer process of optimization. The aim of the present work is to demonstrate the versatility of the use of benign solvents, like acetic acid and formic acid, for the fabrication of microfibrous and nanofibrous electrospun poly(epsilon-caprolactone mats. The solvent systems were also shown to be suitable for the fabrication of electrospun structures with macroporosity, as well as for the fabrication of composite electrospun mats, fabricated by the addition of bioactive glass (45S5 composition particles in the polymeric solution.

  6. The Solvent Selection framework: solvents for organic synthesis, separation processes and ionic-organic synthesis

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Sansonetti, Sascha; Abildskov, Jens

    2012-01-01

    This paper presents a systematic integrated framework for solvent selection and solvent design. The framework is divided into several modules, which can tackle specific problems in various solvent-based applications. In particular, three modules corresponding to the following solvent selection pr...

  7. Solvent cleaning system and method for removing contaminants from solvent used in resin recycling

    Science.gov (United States)

    Bohnert, George W [Harrisonville, MO; Hand, Thomas E [Lee's Summit, MO; DeLaurentiis, Gary M [Jamestown, CA

    2009-01-06

    A two step solvent and carbon dioxide based system that produces essentially contaminant-free synthetic resin material and which further includes a solvent cleaning system for periodically removing the contaminants from the solvent so that the solvent can be reused and the contaminants can be collected and safely discarded in an environmentally safe manner.

  8. Insecticide solvents: interference with insecticidal action.

    Science.gov (United States)

    Brattsten, L B; Wilkinson, C F

    1977-06-10

    Several commercial solvent mixtures commonly used as insecticide carriers in spray formulations increase by more than threefold the microsomal N-demethylation of p-chloro N-methylaniline in midgut preparations of southern army-worm (Spodoptera eridania) larvae exposed orally to the test solvents. Under laboratory conditions, the same solvent mixtures exhibit a protective action against the in vivo toxicity of the insecticide carbaryl to the larvae. The data are discussed with respect to possible solvent-insecticide interactions occurring under field conditions and, more broadly, to potential toxicological hazards of these solvents to humans.

  9. Organic solvents in electromembrane extraction: recent insights

    DEFF Research Database (Denmark)

    Huang, Chuixiu; Gjelstad, Astrid; Pedersen-Bjergaard, Stig

    2016-01-01

    the introduction. Under the influence of an electrical field, EME is based on electrokinetic migration of the analytes through a supported liquid membrane (SLM), which is an organic solvent immobilized in the pores of the polymeric membrane, and into the acceptor solution. Up to date, close to 150 research...... articles with focus on EME have been published. The current review summarizes the performance of EME with different organic solvents and discusses several criteria for efficient solvents in EME. In addition, the authors highlight their personal perspective about the most promising organic solvents for EME...... and have indicated that more fundamental work is required to investigate and discover new organic solvents for EME....

  10. Effect of solvents on the enzyme mediated degradation of copolymers

    International Nuclear Information System (INIS)

    Banerjee, Aditi; Chatterjee, Kaushik; Madras, Giridhar

    2015-01-01

    The biodegradation of polycaprolactone (PCL), polylactic acid (PLA), polyglycolide (PGA) and their copolymers, poly (lactide-co-glycolide) and poly (D, L-lactide-co-caprolactone) (PLCL) was investigated. The influence of different solvents on the degradation of these polymers at 37 °C in the presence of two different lipases namely Novozym 435 and the free lipase of porcine pancreas was investigated. The rate coefficients for the polymer degradation and enzyme deactivation were determined using continuous distribution kinetics. Among the homopolymers, the degradation of PGA was nearly an order of magnitude lower than that for PCL and PLA. The overall rate coefficients of the copolymers were higher than their respective homopolymers. Thus, PLCL degraded faster than either PCL or PLA. The degradation was highly dependent on the viscosity of the solvent used with the highest degradation observed in acetone. The degradation of the polymers in acetone was nearly twice that observed in dimethyl sulfoxide indicating that the degradation decreases with increase in the solvent viscosity. The degradation of the polymers in water-solvent mixtures indicated an optimal water content of 2.5 wt% of water. (paper)

  11. Effect of pH on desorption of CO2 from alkanolamine - rich solvents

    Science.gov (United States)

    Du, Min

    2017-08-01

    Adipic acid was used as a pH regulator, which was added to 0.4 mol/L MEA, DEA and MDEA solvents during CO2 desorption process. It is found that when pH value of the solvents swing between 8-10, CO2 desorption rate enhanced, and energy consumption has declined obviously. This research may have reference significance on optimization of alkanolamine CO2 capture process.

  12. Encapsulation of azithromycin into polymeric microspheres by reduced pressure-solvent evaporation method

    DEFF Research Database (Denmark)

    Li, Xiujuan; Chang, Si; Du, Guangsheng

    2012-01-01

    Azithromycin loaded microspheres with blends of poly-l-lactide and ploy-D,L-lactide-co-glycolide as matrices were prepared by the atmosphere-solvent evaporation (ASE) and reduced pressure-solvent evaporation (RSE) method. Both the X-ray diffraction spectra and DSC thermographs demonstrated...... characteristics and release profiles of microspheres. In conclusion, the overall improvement of microspheres in appearance, encapsulation efficiency and controlled drug release through the RSE method could be easily fulfilled under optimal preparation conditions....

  13. Standardization of solvent extraction procedure for determination of uranium in seawater

    International Nuclear Information System (INIS)

    Sukanta Maity; Sahu, S.K.; Pandit, G.G.

    2015-01-01

    Solvent extraction procedure using ammonium pyrolidine dithiocarbamate complexing agent in methyl isobutyl ketone organic phase and acid exchange back-extraction is described for the simultaneous quantitative pre-concentration of uranium in seawater followed by its determination by differential pulse adsorptive stripping voltammetry. Solvent extraction time is optimized for extraction of uranium from seawater. Solvent extraction efficiency for uranium in seawater at different pH was carried out. The method gives a recovery of 98 ± 2 % for 400 mL sample at pH 3.0 ± 0.02, facilitating the rapid and interference free analysis of seawater samples. (author)

  14. Advanced integrated solvent extraction systems

    Energy Technology Data Exchange (ETDEWEB)

    Horwitz, E.P.; Dietz, M.L.; Leonard, R.A. [Argonne National Lab., IL (United States)

    1997-10-01

    Advanced integrated solvent extraction systems are a series of novel solvent extraction (SX) processes that will remove and recover all of the major radioisotopes from acidic-dissolved sludge or other acidic high-level wastes. The major focus of this effort during the last 2 years has been the development of a combined cesium-strontium extraction/recovery process, the Combined CSEX-SREX Process. The Combined CSEX-SREX Process relies on a mixture of a strontium-selective macrocyclic polyether and a novel cesium-selective extractant based on dibenzo 18-crown-6. The process offers several potential advantages over possible alternatives in a chemical processing scheme for high-level waste treatment. First, if the process is applied as the first step in chemical pretreatment, the radiation level for all subsequent processing steps (e.g., transuranic extraction/recovery, or TRUEX) will be significantly reduced. Thus, less costly shielding would be required. The second advantage of the Combined CSEX-SREX Process is that the recovered Cs-Sr fraction is non-transuranic, and therefore will decay to low-level waste after only a few hundred years. Finally, combining individual processes into a single process will reduce the amount of equipment required to pretreat the waste and therefore reduce the size and cost of the waste processing facility. In an ongoing collaboration with Lockheed Martin Idaho Technology Company (LMITCO), the authors have successfully tested various segments of the Advanced Integrated Solvent Extraction Systems. Eichrom Industries, Inc. (Darien, IL) synthesizes and markets the Sr extractant and can supply the Cs extractant on a limited basis. Plans are under way to perform a test of the Combined CSEX-SREX Process with real waste at LMITCO in the near future.

  15. Deacidification of Soybean Oil Combining Solvent Extraction and Membrane Technology

    Directory of Open Access Journals (Sweden)

    M. L. Fornasero

    2013-01-01

    Full Text Available The aim of this work was to study the removal of free fatty acids (FFAs from soybean oil, combining solvent extraction (liquid-liquid for the separation of FFAs from the oil and membrane technology to recover the solvent through nanofiltration (NF. Degummed soybean oil containing 1.05 ± 0.10% w/w FFAs was deacidified by extraction with ethanol. Results obtained in the experiences of FFAs extraction from oil show that the optimal operating conditions are the following: 1.8 : 1 w : w ethanol/oil ratio, 30 minutes extraction time and high speed of agitation and 30 minutes repose time after extraction at ambient temperature. As a result of these operations two phases are obtained: deacidified oil phase and ethanol phase (containing the FFAs. The oil from the first extraction is subjected to a second extraction under the same conditions, reducing the FFA concentration in oil to 0.09%. Solvent recovery from the ethanol phase is performed using nanofiltration technology with a commercially available polymeric NF membrane (NF-99-HF, Alfa Laval. From the analysis of the results we can conclude that the optimal operating conditions are pressure of 20 bar and temperature of 35°C, allowing better separation performance: permeate flux of 28.3 L/m2·h and FFA retention of 70%.

  16. Comparisons of amine solvents for post-combustion CO{sub 2} capture: A multi-objective analysis approach

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Anita S; Eslick, John C; Miller, David C; Kitchin, John R

    2013-10-01

    Amine solvents are of great interest for post-combustion CO{sub 2} capture applications. Although the development of new solvents is predominantly conducted at the laboratory scale, the ability to assess the performance of newly developed solvents at the process scale is crucial to identifying the best solvents for CO{sub 2} capture. In this work we present a methodology to evaluate and objectively compare the process performance of different solvents. We use Aspen Plus, with the electrolyte-NRTL thermodynamic model for the solvent CO{sub 2} interactions, coupled with a multi-objective genetic algorithm optimization to determine the best process design and operating conditions for each solvent. This ensures that the processes utilized for the comparison are those which are best suited for the specific solvent. We evaluate and compare the process performance of monoethanolamine (MEA), diethanolamine (DEA), and 2-amino-2-methyl-1-propanol (AMP) in a 90% CO{sub 2} capture process from a 550 MW coal fired power plant. From our analysis the best process specifications are amine specific and with those specific, optimized specifications DEA has the potential to be a better performing solvent than MEA, with a lower energy penalty and lower capital cost investment.

  17. The effect of solvent component on the discharge performance of Lithium-sulfur cell containing various organic electrolytes

    International Nuclear Information System (INIS)

    Kim, Seok; Jung, Yongju; Lim, Hong S.

    2004-01-01

    The effect of solvent component on the discharge performance of lithium-sulfur (Li/S) cell and the optimal composition of ternary electrolyte for the improved discharge performance of the cell have been investigated. The capacity value and capacity stability with cycle are dependent on the nature of solvent as well as the composition of mixed solvent. The change trend of discharge performance as a function of content of each solvent component is studied. Capacity value increases as the 1,3-dioxolane (DOX) content decreases. Average discharge voltage shows larger value when the 1,2-dimethoxy ethane (DME) content is small. Finally, we have obtained the optimal solvent composition by using a statistical method

  18. Development of Solvent Extraction Approach to Recycle Enriched Molybdenum Material

    Energy Technology Data Exchange (ETDEWEB)

    Tkac, Peter [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Brown, M. Alex [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Sen, Sujat [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Bowers, Delbert L. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Wardle, Kent [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Copple, Jacqueline M. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Pupek, Krzysztof Z. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Dzwiniel, Trevor L. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Pereira, Candido [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Krumdick, Gregory K. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-06-01

    Argonne National Laboratory, in cooperation with Oak Ridge National Laboratory and NorthStar Medical Technologies, LLC, is developing a recycling process for a solution containing valuable Mo-100 or Mo-98 enriched material. Previously, Argonne had developed a recycle process using a precipitation technique. However, this process is labor intensive and can lead to production of large volumes of highly corrosive waste. This report discusses an alternative process to recover enriched Mo in the form of ammonium heptamolybdate by using solvent extraction. Small-scale experiments determined the optimal conditions for effective extraction of high Mo concentrations. Methods were developed for removal of ammonium chloride from the molybdenum product of the solvent extraction process. In large-scale experiments, very good purification from potassium and other elements was observed with very high recovery yields (~98%).

  19. Deep Eutectic Solvents pretreatment of agro-industrial food waste.

    Science.gov (United States)

    Procentese, Alessandra; Raganati, Francesca; Olivieri, Giuseppe; Russo, Maria Elena; Rehmann, Lars; Marzocchella, Antonio

    2018-01-01

    Waste biomass from agro-food industries are a reliable and readily exploitable resource. From the circular economy point of view, direct residues from these industries exploited for production of fuel/chemicals is a winning issue, because it reduces the environmental/cost impact and improves the eco-sustainability of productions. The present paper reports recent results of deep eutectic solvent (DES) pretreatment on a selected group of the agro-industrial food wastes (AFWs) produced in Europe. In particular, apple residues, potato peels, coffee silverskin, and brewer's spent grains were pretreated with two DESs, (choline chloride-glycerol and choline chloride-ethylene glycol) for fermentable sugar production. Pretreated biomass was enzymatic digested by commercial enzymes to produce fermentable sugars. Operating conditions of the DES pretreatment were changed in wide intervals. The solid to solvent ratio ranged between 1:8 and 1:32, and the temperature between 60 and 150 °C. The DES reaction time was set at 3 h. Optimal operating conditions were: 3 h pretreatment with choline chloride-glycerol at 1:16 biomass to solvent ratio and 115 °C. Moreover, to assess the expected European amount of fermentable sugars from the investigated AFWs, a market analysis was carried out. The overall sugar production was about 217 kt yr -1 , whose main fraction was from the hydrolysis of BSGs pretreated with choline chloride-glycerol DES at the optimal conditions. The reported results boost deep investigation on lignocellulosic biomass using DES. This investigated new class of solvents is easy to prepare, biodegradable and cheaper than ionic liquid. Moreover, they reported good results in terms of sugars' release at mild operating conditions (time, temperature and pressure).

  20. Sustainable development of gree solvent separation process

    OpenAIRE

    Lisickov, Kiril; Fidancevska, Emilija; Grujic, Radoslav; Srebrenkoska, Vineta; Kuvendziev, Stefan

    2011-01-01

    Solvents defi ne a major part of the environmental performance of processes in the chemical industry and impact on cost, safety and health issues. The idea of green solvents expresses the goal to minimize the environmental impact resulting from the use of solvents in chemical production. In spite of conventional separation methods, precise process green technologies are based on the application of modern processes and process equipment as well as control and management...

  1. Supercritical solvent extraction of oil sand bitumen

    Science.gov (United States)

    Imanbayev, Ye. I.; Ongarbayev, Ye. K.; Tileuberdi, Ye.; Mansurov, Z. A.; Golovko, A. K.; Rudyk, S.

    2017-08-01

    The supercritical solvent extraction of bitumen from oil sand studied with organic solvents. The experiments were performed in autoclave reactor at temperature above 255 °C and pressure 29 atm with stirring for 6 h. The reaction resulted in the formation of coke products with mineral part of oil sands. The remaining products separated into SARA fractions. The properties of the obtained products were studied. The supercritical solvent extraction significantly upgraded extracted natural bitumen.

  2. Canyon solvent cleaning with activated alumina

    International Nuclear Information System (INIS)

    Reif, D.J.

    1987-01-01

    This paper presents recent work at SRL concerning the cleaning of solvent extraction solvent used at SRP. The paper explains why we undertook the work, and some laboratory studies on two approaches to solvent cleaning, namely extended carbonate washing and use of solid adsorbents. The paper then discusses scale-up of the preferred method and the results of the full-scale cleaning. 19 figs

  3. Simulation of equilibrium distribution data in a solvent extraction system

    International Nuclear Information System (INIS)

    Mondal, S.; Giriyalkar, A.B.; Singh, A.K.; Singh, D.K.; Hubli, R.C.

    2014-01-01

    In hydrometallurgy, solvent extraction has been proved to be the purification method to recover metal in high-pure form from impure solution. Any solvent extraction process is complex and based on some operating parameters which always lure the scientists to model them. Operating parameters like aqueous to organic volume ratio and concentration of feed are related to required number of stages for a product with specific recovery. So to determine final feed concentration or aqueous to organic volume ratio for a specific extractant concentration, one needs to carry out a number of extraction experiments tediously supported by analysis. Here an attempt is being made to model the distribution of solute between organic and aqueous phases with minimum analytical and experimental support for any system. The model can predict the effect on solvent extraction for a change in the aqueous to organic volume ratio i.e. slope of operating line, percentage loading of solvent, feed concentration, solvent concentration, number of stages and in the process it can help in optimizing conditions for the best result from a solvent extraction system. Uranium-7% TBP in dodecane system was taken up to validate the model. The predicted values of the model was tallied against uranium distribution between aqueous and organic phases in a running mixer settler. The equation for operating line i.e. straight line is derived from O/A=1.5 and considering barren organic contains 2 ppm uranium: y 1 = 0.667x 0 - .002. The extraction isotherm i.e. parabola equation came as : x 1 = 0.003y 0 2 + 0.723y 0 considering three points i.e. (0,0), (13,16.7) (uranium analysis for first stage of mixer-settler) and (25, 30.69) (feed concentration, loading capacity of solvent). Using these two equations the results that were obtained, predicted the solute distribution across different stages exactly as it is in the running mixer settler. Individual isotherms could also be drawn with the predicted results from the

  4. Aminosilicone solvent recovery methods and systems

    Science.gov (United States)

    Spiry, Irina Pavlovna; Perry, Robert James; Wood, Benjamin Rue; Singh, Surinder Prabhjot; Farnum, Rachel Lizabeth; Genovese, Sarah Elizabeth

    2018-02-13

    The present invention is directed to aminosilicone solvent recovery methods and systems. The methods and systems disclosed herein may be used to recover aminosilicone solvent from a carbon dioxide containing vapor stream, for example, a vapor stream that leaves an aminosilicone solvent desorber apparatus. The methods and systems of the invention utilize a first condensation process at a temperature from about 80.degree. C. to about 150.degree. C. and a second condensation process at a temperature from about 5.degree. C. to about 75.degree. C. The first condensation process yields recovered aminosilicone solvent. The second condensation process yields water.

  5. Molecular Thermodynamic Modeling of Mixed Solvent Solubility

    DEFF Research Database (Denmark)

    Ellegaard, Martin Dela; Abildskov, Jens; O’Connell, John P.

    2010-01-01

    A method based on statistical mechanical fluctuation solution theory for composition derivatives of activity coefficients is employed for estimating dilute solubilities of 11 solid pharmaceutical solutes in nearly 70 mixed aqueous and nonaqueous solvent systems. The solvent mixtures range from...... nearly ideal to strongly nonideal. The database covers a temperature range from 293 to 323 K. Comparisons with available data and other existing solubility methods show that the method successfully describes a variety of observed mixed solvent solubility behaviors using solute−solvent parameters from...

  6. Optimization of Temperature Distributions in Critical Cross-sections of Load-bearing Structures of Measurement Optical Systems of Autonomous Objects

    Directory of Open Access Journals (Sweden)

    Livshits Michael Yu.

    2017-01-01

    Full Text Available Problem of the automatic thermogradient stabilization of the constructive elements sizes is discussed. The actual problem is the determination of the control algorithm controlled heat sources, providing them with the minimum possible number of minimal deviation from the desired temperature in a given cross-section design. The proposed procedure for solving optimal control of temperature distribution in the numerical design of its implementation, allows obtaining results that are suitable for approximate implementation in on-Board computers, Autonomous systems and significantly reduce thermal deformation component of the measurement error.

  7. Quantitation of buried contamination by use of solvents. [degradation of silicone polymers by amine solvents

    Science.gov (United States)

    Pappas, S. P.; Hsiao, Y. C.; Hill, L. W.

    1973-01-01

    Spore recovery form cured silicone potting compounds using amine solvents to degrade the cured polymers was investigated. A complete list of solvents and a description of the effect of each on two different silicone polymers is provided.

  8. Cleanup of 7.5% tributyl phosphate/n-paraffin solvent-extraction solvent

    International Nuclear Information System (INIS)

    Reif, D.J.

    1987-02-01

    The HM process at the Savannah River Plant uses 7.5% tributyl phosphate in n-paraffin as an extraction solvent. During use, the solvent is altered due to hydrolysis and radiolysis, forming materials which influence product losses, product decontamination, and separation efficiencies. Laboratory studies to improve online solvent cleaning have shown that carbonate washing, although removing residual solvent activity, does not remove binding ligands which hold fission products in the solvent. Treatment of solvent by an alumina adsorption process removes binding ligands and significantly improves recycle solvent performance. Both laboratory work defining a full-scale alumina adsorption process and the use of the process to clean HM process first cycle solvent is discussed

  9. Implicit solvent simulations of DNA and DNA-protein complexes: Agreement with explicit solvent vs experiment

    Czech Academy of Sciences Publication Activity Database

    Chocholoušová, Jana; Feig, M.

    2006-01-01

    Roč. 110, č. 34 (2006), s. 17240-17251 ISSN 1520-6106 Keywords : implicit solvent * explicit solvent * protein DNA complex Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.115, year: 2006

  10. Fluid management in the intensive care unit: bioelectrical impedance vector analysis as a tool to assess hydration status and optimal fluid balance in critically ill patients.

    Science.gov (United States)

    Basso, Flavio; Berdin, Giovanna; Virzì, Grazia Maria; Mason, Giacomo; Piccinni, Pasquale; Day, Sonya; Cruz, Dinna N; Wjewodzka, Marzena; Giuliani, Anna; Brendolan, Alessandra; Ronco, Claudio

    2013-01-01

    Fluid balance disorders are a relevant risk factor for morbidity and mortality in critically ill patients. Volume assessment in the intensive care unit (ICU) is thus of great importance, but there are currently few methods to obtain an accurate and timely assessment of hydration status. Our aim was to evaluate the hydration status of ICU patients via bioelectric impedance vector analysis (BIVA) and to investigate the relationship between hydration and mortality. We evaluated 280 BIVA measurements of 64 patients performed daily in the 5 days following their ICU admission. The observation period ranged from a minimum of 72 h up to a maximum of 120 h. We observed the evolution of the hydration status during the ICU stay in this population, and analyzed the relationship between mean and maximum hydration reached and mortality--both in the ICU and at 60 days--using logistic regression. A state of overhydration was observed in the majority of patients (70%) on admission, which persisted during the ICU stay. Patients who required continuous renal replacement therapy (CRRT) were more likely to be overhydrated starting from the 2nd day of observation. Logistic regression showed a strong and significant correlation between mean/maximum hydration reached and mortality, both independently and correcting for severity of prognosis. Fluid overload measured by BIVA is a frequent condition in critically ill patients--whether or not they undergo CRRT--and a significant predictor of mortality. Hence, hydration status should be considered as an additional prognosticator in the clinical management of the critically ill patient. (i) On the day of ICU admittance, patients showed a marked tendency to overhydration (>70% of total). This tendency was more pronounced in patients on CRRT. (ii) Hyperhydration persisted during the ICU stay. Patients who underwent CRRT showed significantly higher hyperhydration from the 2nd day of hospitalization. (iii) Nonsurvivors showed worse hyperhydration

  11. Volatile solvents as drugs of abuse: focus on the cortico-mesolimbic circuitry.

    Science.gov (United States)

    Beckley, Jacob T; Woodward, John J

    2013-12-01

    Volatile solvents such as those found in fuels, paints, and thinners are found throughout the world and are used in a variety of industrial applications. However, these compounds are also often intentionally inhaled at high concentrations to produce intoxication. While solvent use has been recognized as a potential drug problem for many years, research on the sites and mechanisms of action of these compounds lags behind that of other drugs of abuse. In this review, we first discuss the epidemiology of voluntary solvent use throughout the world and then consider what is known about their basic pharmacology and how this may explain their use as drugs of abuse. We next present data from preclinical and clinical studies indicating that these substances induce common addiction sequelae such as dependence, withdrawal, and cognitive impairments. We describe how toluene, the most commonly studied psychoactive volatile solvent, alters synaptic transmission in key brain circuits such as the mesolimbic dopamine system and medial prefrontal cortex (mPFC) that are thought to underlie addiction pathology. Finally, we make the case that activity in mPFC circuits is a critical regulator of the mesolimbic dopamine system's ability to respond to volatile solvents like toluene. Overall, this review provides evidence that volatile solvents have high abuse liability because of their selective effects on critical nodes of the addiction neurocircuitry, and underscores the need for more research into how these compounds induce adaptations in neural circuits that underlie addiction pathology.

  12. Optimization of radiotherapy to target volumes with concave outlines: target-dose homogenization and selective sparing of critical structures by constrained matrix inversion

    Energy Technology Data Exchange (ETDEWEB)

    Colle, C; Van den Berge, D; De Wagter, C; Fortan, L; Van Duyse, B; De Neve, W

    1995-12-01

    The design of 3D-conformal dose distributions for targets with concave outlines is a technical challenge in conformal radiotherapy. For these targets, it is impossible to find beam incidences for which the target volume can be isolated from the tissues at risk. Commonly occurring examples are most thyroid cancers and the targets located at the lower neck and upper mediastinal levels related to some head and neck. A solution to this problem was developed, using beam intensity modulation executed with a multileaf collimator by applying a static beam-segmentation technique. The method includes the definition of beam incidences and beam segments of specific shape as well as the calculation of segment weights. Tests on Sherouse`s GRATISTM planning system allowed to escalate the dose to these targets to 65-70 Gy without exceeding spinal cord tolerance. Further optimization by constrained matrix inversion was investigated to explore the possibility of further dose escalation.

  13. Optimization of Methods for Articular Cartilage Surface Tissue Engineering: Cell Density and Transforming Growth Factor Beta Are Critical for Self-Assembly and Lubricin Secretion.

    Science.gov (United States)

    Iwasa, Kenjiro; Reddi, A Hari

    2017-07-01

    Lubricin/superficial zone protein (SZP)/proteoglycan4 (PRG4) plays an important role in boundary lubrication in articular cartilage. Lubricin is secreted by superficial zone chondrocytes and synoviocytes of the synovium. The specific objective of this investigation is to optimize the methods for tissue engineering of articular cartilage surface. The aim of this study is to investigate the effect of cell density on the self-assembly of superficial zone chondrocytes and lubricin secretion as a functional assessment. Superficial zone chondrocytes were cultivated as a monolayer at low, medium, and high densities. Chondrocytes at the three different densities were treated with transforming growth factor beta (TGF-β)1 twice a week or daily, and the accumulated lubricin in the culture medium was analyzed by immunoblots and quantitated by enzyme-linked immunosorbent assay (ELISA). Cell numbers in low and medium densities were increased by TGF-β1; whereas cell numbers in high-density cell cultures were decreased by twice-a-week treatment of TGF-β1. On the other hand, the cell numbers were maintained by daily TGF-β treatment. Immunoblots and quantitation of lubricin by ELISA analysis indicated that TGF-β1 stimulated lubricin secretion by superficial zone chondrocytes at all densities with twice-a-week TGF-β treatment. It is noteworthy that the daily treatment of TGF-β1 increased lubricin much higher compared with twice-a-week treatment. These data demonstrate that daily treatment is optimal for the TGF-β1 response in a higher density of monolayer cultures. These findings have implications for self-assembly of surface zone chondrocytes of articular cartilage for application in tissue engineering of articular cartilage surface.

  14. Optimization extraction conditions for improving phenolic content and antioxidant activity in Berberis asiatica fruits using response surface methodology (RSM).

    Science.gov (United States)

    Belwal, Tarun; Dhyani, Praveen; Bhatt, Indra D; Rawal, Ranbeer Singh; Pande, Veena

    2016-09-15

    This study for the first time designed to optimize the extraction of phenolic compounds and antioxidant potential of Berberis asiatica fruits using response surface methodology (RSM). Solvent selection was done based on the preliminary experiments and a five-factors-three-level, Central Composite Design (CCD). Extraction temperature (X1), sample to solvent ratio (X3) and solvent concentration (X5) significantly affect response variables. The quadratic model well fitted for all the responses. Under optimal extraction conditions, the dried fruit sample mixed with 80% methanol having 3.0 pH in a ratio of 1:50 and the mixture was heated at 80 °C for 30 min; the measured parameters was found in accordance with the predicted values. High Performance Liquid Chromatography (HPLC) analysis at optimized condition reveals 6 phenolic compounds. The results suggest that optimization of the extraction conditions is critical for accurate quantification of phenolics and antioxidants in Berberis asiatica fruits, which may further be utilized for industrial extraction procedure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Solvent-vapor-assisted imprint lithography

    NARCIS (Netherlands)

    Voicu, Nicoleta E.; Ludwigs, Sabine; Crossland, Edward J. W.; Andrew, Piers; Steiner, Ullrich

    2007-01-01

    Sub-micrometer features are replicated into high-molecular-weight polymer resists by using solvent-assisted nanoimprint lithography (see figure). By swelling the polymer in a controlled solvent-vapor atmosphere, millibar pressures and ambient temperatures are sufficient to achieve high-fidelity

  16. Into the depths of deep eutectic solvents

    NARCIS (Netherlands)

    Rodriguez, N.; Alves da Rocha, M.A.; Kroon, M.C.

    2015-01-01

    Ionic liquids (ILs) have been successfully tested in a wide range of applications; however, their high price and complicated synthesis make them infeasible for large scale implementation. A decade ago, a new generation of solvents so called deep eutectic solvents (DESs) was reported for the first

  17. Remediation of Contaminated Soils by Solvent Flushing

    NARCIS (Netherlands)

    Augustijn, Dionysius C.M.; Jessup, Ron E.; Rao, P. Suresh C.; Wood, A. Lynn

    1994-01-01

    Solvent flushing is a potential technique for remediating a waste disposal/spill site contaminated with organic chemicals. This technique involves the injection of a solvent mixture (e.g., water plus alcohols) that enhances contaminant solubility, reduces the retardation factor, and increases the

  18. Structuring of polymer solutions upon solvent evaporation

    NARCIS (Netherlands)

    Schaefer, C.; van der Schoot, P.|info:eu-repo/dai/nl/102140618; Michels, J. J.

    2015-01-01

    The morphology of solution-cast, phase-separated polymers becomes finer with increasing solvent evaporation rate. We address this observation theoretically for a model polymer where demixing is induced by steady solvent evaporation. In contrast to what is the case for a classical, thermal quench

  19. Nonlocal Poisson-Fermi model for ionic solvent.

    Science.gov (United States)

    Xie, Dexuan; Liu, Jinn-Liang; Eisenberg, Bob

    2016-07-01

    We propose a nonlocal Poisson-Fermi model for ionic solvent that includes ion size effects and polarization correlations among water molecules in the calculation of electrostatic potential. It includes the previous Poisson-Fermi models as special cases, and its solution is the convolution of a solution of the corresponding nonlocal Poisson dielectric model with a Yukawa-like kernel function. The Fermi distribution is shown to be a set of optimal ionic concentration functions in the sense of minimizing an electrostatic potential free energy. Numerical results are reported to show the difference between a Poisson-Fermi solution and a corresponding Poisson solution.

  20. Lithium current sources with an electrolyte based on aprotonic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Shembel, Ye.M.; Ksenzhek, O.S.; Litvinova, V.I.; Martynenko, T.L.; Raykhelson, L.B.; Sokolov, L.A.; Strizhko, A.S.

    1984-01-01

    Lithium current sources with an electrolyte based on aprotonic solvents are examined. The effect of the composition of the electrolyte solution on the solubility of SO2 and the excess pressure of the gas above the electrolyte solution is established. The temperature characteristics of the electrolyte are studied from the standpoint of salt solubility, the association between the discharge conditions, the macrostructure of the porous inert cathode and the degree of usage of the active cathode substance of the SO2 as the necessary aspects for solving the problems of optimizing a lithium and SO2 system.

  1. Solvent distillations studies for a reprocessing plant

    International Nuclear Information System (INIS)

    Ginisty, C.; Guillaume, B.

    1989-01-01

    The substantial amounts of solvent used in large reprocessing plants are such that considerable care must be paid to solvent management to limit the production of organic wastes. The installation of intensive treatment by chemical regeneration serves to increase the service life of the solvent. General solvent management, combined with a distillation unit under reduced pressure also helps to recycle the two components of the solvent at a low activity level. Distillation also serves to remove the heavy degradation products that are generally responsible for poor hydraulic behavior and for the holdup of radioactive products such as plutonium, zirconium and ruthenium. From the safety standpoint, the flashpoint of the distilled diluent tends to rise. It can therefore be recycled without risk

  2. Method of decomposing radioactive organic solvent wastes

    International Nuclear Information System (INIS)

    Uki, Kazuo; Ichihashi, Toshio; Hasegawa, Akira; Sato, Tatsuaki

    1986-01-01

    Purpose: To decompose radioactive organic solvent wastes or radioactive hydrocarbon solvents separated therefrom into organic materials under moderate conditions, as well as greatly decrease the amount of secondary wastes generated. Method: Radioactive organic solvent wastes comprising an organic phosphoric acid ester ingredient and a hydrocarbon ingredient as a diluent therefor, or radioactive hydrocarbon solvents separated therefrom are oxidatively decomposed by hydrogen peroxide in an aqueous phosphoric acid solution of phosphoric acid metal salts finally into organic materials to perform decomposing treatment for the radioactive organic solvent wastes. The decomposing reaction is carried out under relatively moderate conditions and cause less burden to facilities or the likes. Further, since the decomposed liquid after the treatment can be reused for the decomposing reaction as a catalyst solution secondary wastes can significantly be decreased. (Yoshihara, H.)

  3. The chemistry of nonaqueous solvents v.4 solution phenomena and aprotic solvents

    CERN Document Server

    Lagowski, J J

    1976-01-01

    The Chemistry of Nonaqueous Solvents, Volume IV: Solution Phenomena and Aprotic Solvents focuses on the chemistry of nonaqueous solvents, with emphasis on solution phenomena and aprotic solvents such as tetramethylurea, inorganic acid chlorides, cyclic carbonates, and sulfolane. This book is organized into seven chapters and begins with an overview of the theory of electrical conductivity and elementary experimental considerations, along with some of the interesting research on nonaqueous solvents. It then turns to a discussion on hydrogen bonding phenomena in nonaqueous systems as probed

  4. PARIS II: Computer Aided Solvent Design for Pollution Prevention

    Science.gov (United States)

    This product is a summary of U.S. EPA researchers' work developing the solvent substitution software tool PARIS II (Program for Assisting the Replacement of Industrial Solvents, version 2.0). PARIS II finds less toxic solvents or solvent mixtures to replace more toxic solvents co...

  5. Solubility of cefoxitin acid in different solvent systems

    International Nuclear Information System (INIS)

    Yuan, Fuhong; Wang, Yongli; Xiao, Liping; Huang, Qiaoyin; Xu, Jinchao; Jiang, Chen; Hao, Hongxun

    2016-01-01

    Highlights: • The solubility of cefoxitin acid in different solvent systems was measured. • Three models were used to correlate the solubility data. • The dissolution enthalpy of the dissolution process was calculated. - Abstract: Cefoxitin acid is one kind of important pharmaceutical intermediate. Its solubility is crucial for designing and optimizing the crystallization processes. In this work, the solubility of cefoxitin acid in organic solvents (methanol, acetonitrile, ethanol, isopropanol, n-propanol and ethyl acetate), water and water-methanol mixtures was measured spectrophotometrically using a shake-flask method within the temperature range 278.15–303.15 K. PXRD data and the Karl Fischer method were used to verify the crystal form stability of cefoxitin acid in the solubility measuring process. The melting points, the enthalpy and entropy of fusion were estimated. Results showed that the solubility of cefoxitin acid increases with the increasing temperature in all tested solvents in this work, and the solubility of cefoxitin acid increases with the increasing methanol concentration in water-methanol mixtures. The experimental solubility values were well correlated using the modified Apelblat equation, NRTL model and CNIBS/R-K model. An equation proposed by Williamson was adopted to calculate the molar enthalpy during the dissolution process.

  6. Optimization and critical evaluation of decellularization strategies to develop renal extracellular matrix scaffolds as biological templates for organ engineering and transplantation.

    Science.gov (United States)

    Caralt, M; Uzarski, J S; Iacob, S; Obergfell, K P; Berg, N; Bijonowski, B M; Kiefer, K M; Ward, H H; Wandinger-Ness, A; Miller, W M; Zhang, Z J; Abecassis, M M; Wertheim, J A

    2015-01-01

    The ability to generate patient-specific cells through induced pluripotent stem cell (iPSC) technology has encouraged development of three-dimensional extracellular matrix (ECM) scaffolds as bioactive substrates for cell differentiation with the long-range goal of bioengineering organs for transplantation. Perfusion decellularization uses the vasculature to remove resident cells, leaving an intact ECM template wherein new cells grow; however, a rigorous evaluative framework assessing ECM structural and biochemical quality is lacking. To address this, we developed histologic scoring systems to quantify fundamental characteristics of decellularized rodent kidneys: ECM structure (tubules, vessels, glomeruli) and cell removal. We also assessed growth factor retention--indicating matrix biofunctionality. These scoring systems evaluated three strategies developed to decellularize kidneys (1% Triton X-100, 1% Triton X-100/0.1% sodium dodecyl sulfate (SDS) and 0.02% Trypsin-0.05% EGTA/1% Triton X-100). Triton and Triton/SDS preserved renal microarchitecture and retained matrix-bound basic fibroblast growth factor and vascular endothelial growth factor. Trypsin caused structural deterioration and growth factor loss. Triton/SDS-decellularized scaffolds maintained 3 h of leak-free blood flow in a rodent transplantation model and supported repopulation with human iPSC-derived endothelial cells and tubular epithelial cells ex vivo. Taken together, we identify an optimal Triton/SDS-based decellularization strategy that produces a biomatrix that may ultimately serve as a rodent model for kidney bioengineering. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

  7. Distribution of multi-component solvents in solvent vapor extraction chamber

    Energy Technology Data Exchange (ETDEWEB)

    Das, S. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Marathon Oil Corp., Houston, TX (United States)

    2008-10-15

    Vapex process performance is sensitive to operating pressures, temperatures and the types of solvent used. The hydrocarbon solvents used in Vapex processes typically have between 5 and 10 per cent hydrocarbon impurities, and the accumulation of dense phases inside the vapor chamber reduces gravity drainage potential. This study investigated the partitioning of solvent compounds inside the vapor chamber during in situ Vapex processes.The aim of the study was to examine how the different components of the mixed solvent partitioned inside the extracted chamber during the oil and vapor phase. A 2-D homogenous reservoir model was used to simulate the Vapex process with a solvent mixture comprised of propane and methane at various percentages. The effect of injecting a hot solvent vapor was also investigated. The study showed that injected methane accumulated at both the top and the extraction interface. Accumulations near the top had a positive impact on solvent confinement in thin reservoirs. Diffusion of the solvent component was controlled by gas phase molecular diffusion, and was much faster than the diffusion of solvent molecules in the liquid phase. The use of hot solvent mixtures slowed the extraction process due to lower solvent solubility in the oil phase. It was concluded that the negative impact on viscosity reduction by dilution was not compensated by rises in temperature. 6 refs., 11 figs.

  8. Experiment on the treatment of waste extraction solvent from the molybdenum-99 process

    Energy Technology Data Exchange (ETDEWEB)

    Hsien-Ming Hsiao; Chang-Liang Hu; Kuang-Li Chien; Wen-Cheng Lee; Tsong-Yang Wei [Division of Chemical Engineering, Institute of Nuclear Energy Research, P.O. Box 3-7, Longtan 32546 Taiwan (China)

    2013-07-01

    In the Mo-99 (Molybdenum-99) isotope extraction test process for radiopharmaceutical applications, organic solvent is used to extract Mo-99 from an irradiated UO{sub 2} dissolution. The extraction solvent was stored when the test work was stopped. A total of about 120 liters of waste solvent was stored at INER (Institute of Nuclear Energy Research, Taiwan). The extraction solvent consisted of 5% di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and kerosene. The radionuclides found in the waste solvent include Cs-137, Am-241, Tc-99, and Sr-90, which give off gross alpha and beta radioactivity of 1898 and 471 Bq/ml, respectively. This study aims to remove radionuclides from the waste solvent using sodium carbonate and sodium hydroxide solutions in different concentrations. After mixing the waste solvent with the alkaline solution followed by settling, a third phase other than organic and aqueous phase appeared which is expected due to the saponification reaction. The experimental results showed that increasing the number of washing and the alkaline solution concentration could enhance the radionuclides removal rate. An optimal removal method was proposed using 2 M Na{sub 2}CO{sub 3} solution twice followed by 1 M NaOH solution one time for the third phase generated early in the mixing stages. The remaining gross alpha and beta radioactivity of the treated organic solvent was 2 and 3 Bq/ml, respectively. The treated solvent could be stabilized by ashing at 500 deg. C and then immobilized. The alkaline solution would be neutralized by hydrochloric or nitric acid and then treated using a variety of adsorbents or bone char via adsorption to remove nuclides to meet the wastewater discharge limitation. (authors)

  9. Characterization of Catalytic Fast Pyrolysis Oils: The Importance of Solvent Selection for Analytical Method Development

    Energy Technology Data Exchange (ETDEWEB)

    Ferrell, Jack R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ware, Anne E [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-02-25

    Two catalytic fast pyrolysis (CFP) oils (bottom/heavy fraction) were analyzed in various solvents that are used in common analytical methods (nuclear magnetic resonance - NMR, gas chromatography - GC, gel permeation chromatography - GPC, thermogravimetric analysis - TGA) for oil characterization and speciation. A more accurate analysis of the CFP oils can be obtained by identification and exploitation of solvent miscibility characteristics. Acetone and tetrahydrofuran can be used to completely solubilize CFP oils for analysis by GC and tetrahydrofuran can be used for traditional organic GPC analysis of the oils. DMSO-d6 can be used to solubilize CFP oils for analysis by 13C NMR. The fractionation of oils into solvents that did not completely solubilize the whole oils showed that miscibility can be related to the oil properties. This allows for solvent selection based on physico-chemical properties of the oils. However, based on semi-quantitative comparisons of the GC chromatograms, the organic solvent fractionation schemes did not speciate the oils based on specific analyte type. On the other hand, chlorinated solvents did fractionate the oils based on analyte size to a certain degree. Unfortunately, like raw pyrolysis oil, the matrix of the CFP oils is complicated and is not amenable to simple liquid-liquid extraction (LLE) or solvent fractionation to separate the oils based on the chemical and/or physical properties of individual components. For reliable analyses, for each analytical method used, it is critical that the bio-oil sample is both completely soluble and also not likely to react with the chosen solvent. The adoption of the standardized solvent selection protocols presented here will allow for greater reproducibility of analysis across different users and facilities.

  10. A method for processing the critical zone of a carbonate stratum

    Energy Technology Data Exchange (ETDEWEB)

    Dytyuk, L T; Barsukov, A V; Bragina, O A; Kalabina, A V; Samakayev, R Kh

    1982-01-01

    A method is proposed for processing the critical zone of a carbonate stratum by pumping a carbonate rock solvent into it. It is distinguished by the fact that in order to increase the penetration depth of the solvent into the stratum by reducing the speed of interaction of the solvent, a solution of beta-phenoxyvinylphosphonic acid is pumped into the critical zone of the stratum.

  11. How to improve a critical performance for an ExoMars 2020 Scientific Instrument (RLS). Raman Laser Spectrometer Signal to Noise Ratio (SNR) Optimization

    Science.gov (United States)

    Canora, C. P.; Moral, A. G.; Rull, F.; Maurice, S.; Hutchinson, I.; Ramos, G.; López-Reyes, G.; Belenguer, T.; Canchal, R.; Prieto, J. A. R.; Rodriguez, P.; Santamaria, P.; Berrocal, A.; Colombo, M.; Gallago, P.; Seoane, L.; Quintana, C.; Ibarmia, S.; Zafra, J.; Saiz, J.; Santiago, A.; Marin, A.; Gordillo, C.; Escribano, D.; Sanz-Palominoa, M.

    2017-09-01

    The Raman Laser Spectrometer (RLS) is one of the Pasteur Payload instruments, within the ESA's Aurora Exploration Programme, ExoMars mission. Raman spectroscopy is based on the analysis of spectral fingerprints due to the inelastic scattering of light when interacting with matter. RLS is composed by Units: SPU (Spectrometer Unit), iOH (Internal Optical Head), and ICEU (Instrument Control and Excitation Unit) and the harnesses (EH and OH). The iOH focuses the excitation laser on the samples and collects the Raman emission from the sample via SPU (CCD) and the video data (analog) is received, digitalizing it and transmiting it to the processor module (ICEU). The main sources of noise arise from the sample, the background, and the instrument (Laser, CCD, focuss, acquisition parameters, operation control). In this last case the sources are mainly perturbations from the optics, dark signal and readout noise. Also flicker noise arising from laser emission fluctuations can be considered as instrument noise. In order to evaluate the SNR of a Raman instrument in a practical manner it is useful to perform end-to-end measurements on given standards samples. These measurements have to be compared with radiometric simulations using Raman efficiency values from literature and taking into account the different instrumental contributions to the SNR. The RLS EQM instrument performances results and its functionalities have been demonstrated in accordance with the science expectations. The Instrument obtained SNR performances in the RLS EQM will be compared experimentally and via analysis, with the Instrument Radiometric Model tool. The characterization process for SNR optimization is still on going. The operational parameters and RLS algorithms (fluorescence removal and acquisition parameters estimation) will be improved in future models (EQM-2) until FM Model delivery.

  12. Perpendicular Structure Formation of Block Copolymer Thin Films during Thermal Solvent Vapor Annealing: Solvent and Thickness Effects

    Directory of Open Access Journals (Sweden)

    Qiuyan Yang

    2017-10-01

    Full Text Available Solvent vapor annealing of block copolymer (BCP thin films can produce a range of interesting morphologies, especially when the perpendicular orientation of micro-domains with respect to the substrate plays a role. This, for instance, allows BCP thin films to serve as useful templates for nanolithography and hybrid materials preparation. However, precise control of the arising morphologies is essential, but in most cases difficult to achieve. In this work, we investigated the solvent and thickness effects on the morphology of poly(styrene-b-2 vinyl pyridine (PS-b-P2VP thin films with a film thickness range from 0.4 L0 up to 0.8 L0. Ordered perpendicular structures were achieved. One of the main merits of our work is that the phase behavior of the ultra-high molecular weight BCP thin films, which hold a 100-nm sized domain distance, can be easily monitored via current available techniques, such as scanning electron microscope (SEM, atomic force microscope (AFM, and transmission electron microscope (TEM. Systematic monitoring of the self-assembly behavior during solvent vapor annealing can thus provide an experimental guideline for the optimization of processing conditions of related BCP films systems.

  13. Thinking Critically about Critical Thinking

    Science.gov (United States)

    Mulnix, Jennifer Wilson

    2012-01-01

    As a philosophy professor, one of my central goals is to teach students to think critically. However, one difficulty with determining whether critical thinking can be taught, or even measured, is that there is widespread disagreement over what critical thinking actually is. Here, I reflect on several conceptions of critical thinking, subjecting…

  14. Organic Solvent Tolerant Lipases and Applications

    Directory of Open Access Journals (Sweden)

    Shivika Sharma

    2014-01-01

    Full Text Available Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s could be performed in water-restricted organic media as organic solvent(s not only improve(s the solubility of substrate and reactant in reaction mixture but also permit(s the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented.

  15. Micron-sized columnar grains of CH3NH3PbI3 grown by solvent-vapor assisted low-temperature (75 °C) solid-state reaction: The role of non-coordinating solvent-vapor

    Science.gov (United States)

    Zheng, Huifeng; Liu, Yangqiao; Sun, Jing

    2018-04-01

    The preparation of hybrid perovskite films with large columnar grains via low-temperature solid-state reaction remains a big challenge. Conventional solvent annealing using DMF, DMSO and ethanol, etc. fails to work effectively at low temperature (solar cells based on benzyl-alcohol-vapor annealing (75 °C), delivered much higher photovoltaic performance, better stability and smaller hysteresis than those based on conventional thermal annealing. Additionally, a champion power conversion efficiency (PCE) of 15.1% was obtained and the average PCE reached 12.2% with a tiny deviation. Finally, the mechanism of solvent annealing with non-coordinating solvent was discussed. Moreover, we revealed that high polarity and high boiling point of the solvent used for generating vapor, was critical to grow micron-sized columnar grains at such a low temperature (75 °C). This work will contribute to understanding the mechanism of grain growth in solvent annealing and improving its facility and effectiveness.

  16. Security constrained optimal power flow by modern optimization tools

    African Journals Online (AJOL)

    The main objective of an optimal power flow (OPF) functions is to optimize .... It is characterized as propagation of plants and this happens by gametes union. ... ss and different variables, for example, wind, nearby fertilization can have a critic.

  17. Solvent Handbook Database System user's manual

    International Nuclear Information System (INIS)

    1993-03-01

    Industrial solvents and cleaners are used in maintenance facilities to remove wax, grease, oil, carbon, machining fluids, solder fluxes, mold release, and various other contaminants from parts, and to prepare the surface of various metals. However, because of growing environmental and worker-safety concerns, government regulations have already excluded the use of some chemicals and have restricted the use of halogenated hydrocarbons because they affect the ozone layer and may cause cancer. The Solvent Handbook Database System lets you view information on solvents and cleaners, including test results on cleaning performance, air emissions, recycling and recovery, corrosion, and non-metals compatibility. Company and product safety information is also available

  18. Modeling of Salt Solubilities in Mixed Solvents

    DEFF Research Database (Denmark)

    Chiavone-Filho, O.; Rasmussen, Peter

    2000-01-01

    A method to correlate and predict salt solubilities in mixed solvents using a UNIQUAC+Debye-Huckel model is developed. The UNIQUAC equation is applied in a form with temperature-dependent parameters. The Debye-Huckel model is extended to mixed solvents by properly evaluating the dielectric...... constants and the liquid densities of the solvent media. To normalize the activity coefficients, the symmetric convention is adopted. Thermochemical properties of the salt are used to estimate the solubility product. It is shown that the proposed procedure can describe with good accuracy a series of salt...

  19. Solvent extraction in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Eccles, H.; Naylor, A.

    1987-01-01

    Solvent extraction techniques have been used in the uranium nuclear fuel cycle in three main areas; concentration of uranium from ore leach liquor, purification of ore concentrates and fuel reprocessing. Solvent extraction has been extended to the removal of transuranic elements from active waste liquor, the recovery of uranium from natural sources and the recovery of noble metals from active waste liquor. Schemes are presented for solvent extraction of uranium using the Amex or Dapex process; spent fuel reprocessing and the Purex process. Recent and future developments of the techniques are outlined. (UK)

  20. Chemical reactions in solvents and melts

    CERN Document Server

    Charlot, G

    1969-01-01

    Chemical Reactions in Solvents and Melts discusses the use of organic and inorganic compounds as well as of melts as solvents. This book examines the applications in organic and inorganic chemistry as well as in electrochemistry. Organized into two parts encompassing 15 chapters, this book begins with an overview of the general properties and the different types of reactions, including acid-base reactions, complex formation reactions, and oxidation-reduction reactions. This text then describes the properties of inert and active solvents. Other chapters consider the proton transfer reactions in

  1. Spreadsheet algorithm for stagewise solvent extraction

    International Nuclear Information System (INIS)

    Leonard, R.A.; Regalbuto, M.C.

    1994-01-01

    The material balance and equilibrium equations for solvent extraction processes have been combined with computer spreadsheets in a new way so that models for very complex multicomponent multistage operations can be setup and used easily. A part of the novelty is the way in which the problem is organized in the spreadsheet. In addition, to facilitate spreadsheet setup, a new calculational procedure has been developed. The resulting Spreadsheet Algorithm for Stagewise Solvent Extraction (SASSE) can be used with either IBM or Macintosh personal computers as a simple yet powerful tool for analyzing solvent extraction flowsheets. 22 refs., 4 figs., 2 tabs

  2. TRUEX process solvent cleanup with solid sorbents

    International Nuclear Information System (INIS)

    Tse, Pui-Kwan; Reichley-Yinger, L.; Vandegrift, G.F.

    1989-01-01

    Solid sorbents, alumina, silica gel, and Amberlyst A-26 have been tested for the cleanup of degraded TRUEX-NPH solvent. A sodium carbonate scrub alone does not completely remove acidic degradation products from highly degraded solvent and cannot restore the stripping performance of the solvent. By following the carbonate scrub with either neutral alumina or Amberlyst A-26 anion exchange resin, the performance of the TRUEX-NPH is substantially restored. The degraded TRUEX-NPH was characterized before and after treatment by supercritical fluid chromatography. Its performance was evaluated by americium distribution ratios, phase-separation times, and lauric acid distribution coefficients. 17 refs., 2 figs., 5 tabs

  3. Solvent and temperature effects on the platinum-catalyzed oxidative coupling of 1-naphthols

    CSIR Research Space (South Africa)

    Maphoru, MV

    2015-08-01

    Full Text Available one-pot two-step oxidation of 1-naphthols to the diones (e.g. 81 % from 4-methoxy-1- naphthol). In most other solvents (reflux) naphthoquinones are observed as byproducts. In an attempt to optimize the yield of menadione, 30.5 % was obtained in boiling...

  4. Uranium refining by solvent extraction

    International Nuclear Information System (INIS)

    Kraikaew, J.; Srinuttrakul, W.

    2014-01-01

    The solvent extraction process to produce higher purity uranium from yellowcake was studied in laboratory scale. Yellowcake, which the uranium purity is around 70% and the main impurity is thorium, was obtained from monazite processing pilot plant of Rare Earth Research and Development Center in Thailand. For uranium re-extraction process, the extractant chosen was Tributylphosphate (TBP) in kerosene. It was found that the optimum concentration of TBP was 10% in kerosene and the optimum nitric acid concentration in uranyl nitrate feed solution was 4 N. An increase in concentrations of uranium and thorium in feed solution resulted in a decrease in the distribution of both components in the extractant. However, the distribution of uranium into the extractant was found to be more than that of thorium. The equilibration study of the extraction system, UO_2(NO_3)/4N HNO_3 – 10%TBP/Kerosene, was also investigated. Two extraction stages were calculated graphically from 100,000 ppm uranium concentration in feed solution input with 90% extraction efficiency and the flow ratio of aqueous phase to organic phase was adjusted to 1.0. For thorium impurity scrubbing process, 10% TBP in kerosene was loaded with uranium and minor thorium from uranyl nitrate solution prepared from yellowcake and was scrubbed with different low concentration nitric acid. The results showed that at nitric acid normality was lower than 1 N, uranium distributed well to aqueous phase. As conclusion, optimum nitric acid concentration for scrubbing process should not less than 1 N and diluted nitric acid or de-ionized water should be applied to strip uranium from organic phase in the final refining process. (author)

  5. Critical Care

    Science.gov (United States)

    Critical care helps people with life-threatening injuries and illnesses. It might treat problems such as complications from surgery, ... attention by a team of specially-trained health care providers. Critical care usually takes place in an ...

  6. Comparison of the Behaviour of Polymers in Supercritical Fluids and Organic Solvents Via Small Angle Neutron Scattering

    International Nuclear Information System (INIS)

    Melnichenko, Y.B.; Kiran, E.; Heath, K.D.; Salaniwal, S.; Cochran, H.D.; Stamm, M.; Van Hook, W.A.; Wignall, G.D.

    1999-01-01

    Small-angle neutron scattering has been used to study the effect of temperature and pressure on the phase behavior of semidilute solutions of polymers dissolved in organic and supercritical solvents. Above the theta temperature (To), these systems exhibit a ''good solvent'' domain, where the molecules expand beyond the unperturbed dimensions in both organic solvents and in COZ. However, this transition can be made to occur at a critical ''theta pressure'' (PO) in CO2 and this represents a new concept in the physics of polymer-solvent systems. For T < To, and P < Po, the system enters the ''poor solvent'' domain where diverging concentration fluctuations prevent the chains from collapsing and allow them to maintain their unperturbed dimensions

  7. Taking Stock of Unrealistic Optimism

    Science.gov (United States)

    Shepperd, James A.; Klein, William M. P.; Waters, Erika A.; Weinstein, Neil D.

    2015-01-01

    Researchers have used terms such as unrealistic optimism and optimistic bias to refer to concepts that are similar but not synonymous. Drawing from three decades of research, we critically discuss how researchers define unrealistic optimism and we identify four types that reflect different measurement approaches: unrealistic absolute optimism at the individual and group level and unrealistic comparative optimism at the individual and group level. In addition, we discuss methodological criticisms leveled against research on unrealistic optimism and note that the criticisms are primarily relevant to only one type—the group form of unrealistic comparative optimism. We further clarify how the criticisms are not nearly as problematic even for unrealistic comparative optimism as they might seem. Finally, we note boundary conditions on the different types of unrealistic optimism and reflect on five broad questions that deserve further attention. PMID:26045714

  8. Taking Stock of Unrealistic Optimism.

    Science.gov (United States)

    Shepperd, James A; Klein, William M P; Waters, Erika A; Weinstein, Neil D

    2013-07-01

    Researchers have used terms such as unrealistic optimism and optimistic bias to refer to concepts that are similar but not synonymous. Drawing from three decades of research, we critically discuss how researchers define unrealistic optimism and we identify four types that reflect different measurement approaches: unrealistic absolute optimism at the individual and group level and unrealistic comparative optimism at the individual and group level. In addition, we discuss methodological criticisms leveled against research on unrealistic optimism and note that the criticisms are primarily relevant to only one type-the group form of unrealistic comparative optimism. We further clarify how the criticisms are not nearly as problematic even for unrealistic comparative optimism as they might seem. Finally, we note boundary conditions on the different types of unrealistic optimism and reflect on five broad questions that deserve further attention.

  9. [Chemical hazards when working with solvent glues].

    Science.gov (United States)

    Domański, Wojciech; Makles, Zbigniew

    2012-01-01

    Solvent glues are used in a wide variety of industries, e.g., textile, footwear and rubber. The problem of workers' exposure to solvent vapors is rarely tackled within the area of occupational safety and health in small and medium-sized enterprises. In order to assess exposure to solvents, organic solvents emitted by glues were identified in the samples of workplace air. The concentration of acetone, benzene, cyclohexane, ethylbenzene, n-hexane, methylcyclohexane, butyl acetate and toluene were determined. The obtained results evidenced the presence of cyclohexane, ethylbenzene, ethylcyclohexane, heptane, n-hexane, o-xylene, methylcyclohexane, methylcyclopentane, butyl acetate and toluene in workplace air. The concentration of those compounds in workplace air was low, usually below 0.15 of MAC. At some workstations the presence of benzene was also observed. Occupational risk was assessed at workstations where gluing took place. It showed that the risk at those workstations was medium or low.

  10. Organic solvents from sugar cane molasses

    Energy Technology Data Exchange (ETDEWEB)

    Oeser, H

    1970-01-01

    The production of organic solvents by fermentation of low priced cane molasses is discussed. Processes described and illustrated in detail include the production of acetone, butanol, ethanol, acetic acid, ethyl acetate and butyl acetate.

  11. Solvent induced supramolecular anisotropy in molecular gels

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Michael A., E-mail: mroger09@uoguelph.ca [Department of Food Science, University of Guelph, Guelph, Ontario, N3C3X9 (Canada); Corradini, Maria G. [Department of Food Science, University of Massachusetts Amherst, Amherst, MA, 01003 (United States); Emge, Thomas [Department of Chemistry and Biochemistry, Rutgers University, New Brunswick, NJ, 08901 (United States)

    2017-06-15

    Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

  12. Solvent induced supramolecular anisotropy in molecular gels

    International Nuclear Information System (INIS)

    Rogers, Michael A.; Corradini, Maria G.; Emge, Thomas

    2017-01-01

    Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

  13. Full scale solvent extraction remedial results

    International Nuclear Information System (INIS)

    Cash, A.B.

    1992-01-01

    Sevenson Extraction Technology, Inc. has completed the development of the Soil Restoration Unit (initially developed by Terra-Kleen Corporation), a mobile, totally enclosed solvent extraction treatment facility for the removal of organic contaminated media is greater by a closed loop, counter current process that recycles all solvents. The solvents used are selected for the individual site dependant upon the contaminants, such as PCB's, oil, etc. and the soil conditions. A mixture of up to fourteen non-toxic solvents can be used for complicated sites. The full scale unit has been used to treat one superfund site, the Traband Site in Tulsa, Oklahoma, and is currently treating another superfund site, the Pinette's Salvage Yard Site in Washburn, Maine. The full scale Soil Restoration Unit has also been used at a non-superfund site, as part of a TSCA Research and Development permit. The results from these sites will be discussed in brief herein, and in more detail in the full paper

  14. Enantioselective solvent-free Robinson annulation reactions

    Indian Academy of Sciences (India)

    Unknown

    solvents to effect an asymmetric synthesis is an important step forward towards ... In continuation of our preliminary communication 2, we wish to ..... formation of chiral enamine 74 from the reaction of S-proline with pro-R carbonyl group.

  15. STUDIES ON SOLVENT EXTRACTION OF FREE HYDROGEN ...

    African Journals Online (AJOL)

    synthesized through glucose degradation (glycolysis) to lactic acid. ... g sample into a well stoppered plastic bottle and mixed with 20 mL of distilled .... Recovery of used solvent is necessary because methylchloroform is toxic to the bacteria.

  16. Green and Bio-Based Solvents.

    Science.gov (United States)

    Calvo-Flores, Francisco G; Monteagudo-Arrebola, María José; Dobado, José A; Isac-García, Joaquín

    2018-04-24

    Chemical reactions and many of the procedures of separation and purification employed in industry, research or chemistry teaching utilize solvents massively. In the last decades, with the birth of Green Chemistry, concerns about the employment of solvents and the effects on human health, as well as its environmental impacts and its dependence on non-renewable raw materials for manufacturing most of them, has drawn the attention of the scientific community. In this work, we review the concept of green solvent and the properties and characteristics to be considered green. Additionally, we discuss the different possible routes to prepare many solvents from biomass, as an alternative way to those methods currently applied in the petrochemical industry.

  17. Activity coefficients of solutes in binary solvents

    International Nuclear Information System (INIS)

    Gokcen, N.A.

    1982-01-01

    The activity coefficients in dilute ternary systems are discussed in detail by using the Margules equations. Analyses of some relevant data at high temperatures show that the sparingly dissolved solutes in binary solvents follow complex behavior even when the binary solvents are very nearly ideal. It is shown that the activity data on the solute or the binary system cannot permit computation of the remaining activities except for the regular solutions. It is also shown that a fourth-order equation is usually adequate in expressing the activity coefficient of a solute in binary solvents at high temperatures. When the activity data for a binary solvent are difficult to obtain in a certain range of composition, the activity data for a sparingly dissolved solute can be used to supplement determination of the binary activities

  18. Drying of water based foundry coatings: Innovative test, process design and optimization methods

    DEFF Research Database (Denmark)

    Di Muoio, Giovanni Luca; Johansen, Bjørn Budolph

    on real industrial cases. These tools have been developed in order to simulate and optimize the drying process and reduce drying time and power consumption as well as production process design time and cost of expensive drying equipment. Results show that test methods from other industries can be used...... capacity goals there is a need to understand how to design, control and optimize drying processes. The main focus of this project was on the critical parameters and properties to be controlled in production in order to achieve a stable and predictable drying process. We propose for each of these parameters...... of Denmark with the overall aim to optimize the drying process of water based foundry coatings. Drying of foundry coatings is a relatively new process in the foundry industry that followed the introduction of water as a solvent. In order to avoid moisture related quality problems and reach production...

  19. High-yield exfoliation of graphene using ternary-solvent strategy for detecting volatile organic compounds

    Science.gov (United States)

    Zhang, Shao-Lin; Zhang, Zhijun; Yang, Woo-Chul

    2016-01-01

    Despite the great progress in the theory and experimental verification we made in past decade, the practical application of graphene is still hindered by the lack of efficient, economical, scalable, ease-processing exfoliation method. Herein, we propose a facile, low-cost, and efficient liquid-phase exfoliation process using low boiling-temperature solvent mixture to fabricate few-layer graphene in large scale. The Hansen solubility parameter theory was applied to help optimize the composition of solvent mixture. Aqueous-based ternary-solvent mixture, for the first time, was adapted to exfoliate graphene. We demonstrate that the exfoliation efficiency using ternary-solvent mixture surpasses that from binary-solvent approach. The final product concentration after optimization was over 260 μg/ml. The concentrated graphene dispersion was used to fabricate gas sensor for detecting volatile organic gases. Taking advantage of large surface area, large number of adsorption sites, and well-preserved basal plane, the mass-produced graphene nanosheets exhibited promising sensing potential toward ethanol and methanol vapors.

  20. [Simultaneous determination of seven residual solvents in bovis calculus artifactus by headspace gas chromatography].

    Science.gov (United States)

    Chi, Shuyao; Wu, Dike; Sun, Jinhong; Ye, Ruhan; Wang, Xiaoyan

    2014-05-01

    A headspace gas chromatography (HS-GC) method was developed for the simultaneous determination of seven residual solvents (petroleum ether (60-90 degrees C), acetone, ethyl acetate, methanol, methylene chloride, ethanol and butyl acetate) in bovis calculus artifactus. The DB-WAX capillary column and flame ionization detector (FID) were used for the separation and detection of the residual solvents, and the internal standard method was used for the quantification. The chromatographic conditions, such as equilibrium temperature and equilibrium time, were optimized. Under the optimized conditions, all of the seven residual solvents showed good linear relationships with good correlation coefficients (not less than 0.999 3) in the prescribed concentration range. At three spiked levels, the recoveries for the seven residual solvents were 94.7%-105.2% with the relative standard deviations (RSDs) less than 3.5%. The limits of detection (LODs) of the method were 0.43-5.23 mg/L, and the limits of quantification (LOQs) were 1.25-16.67 mg/L. The method is simple, rapid, sensitive and accurate, and is suitable for the simultaneous determination of the seven residual solvents in bovis calculus artifactus.

  1. An overview of industrial solvent use or is there life after chlorinated solvents?

    International Nuclear Information System (INIS)

    Green, B.

    1991-01-01

    Everyone using industrial chemicals has been affected by the fire- storm of new regulations governing solvent use. How will companies currently using hazardous solvents prepare for the changes ahead? What will the impact be on commonly used industrial solvents? What effect are environmental pressures having on solvent use and disposal? Are the responsible individuals in your company up-to-date on phase-out schedules? This paper is written for an audience of compliance coordinators, consultants, production engineers and corporate management. In it, the either addresses the above questions and discusses the specific products affected. The author reviews currently available alternatives to chlorinated and hazardous solvents and introduces a simple system for rating alternatives. The program also includes a discussion of solvent minimization programs and worker reeducation

  2. Occupational exposure to solvents and bladder cancer

    DEFF Research Database (Denmark)

    Hadkhale, Kishor; Martinsen, Jan Ivar; Weiderpass, Elisabete

    2017-01-01

    logistic regression model was used to estimate hazard ratios (HR) and their 95% confidence intervals (95% CI). Increased risks were observed for trichloroethylene (HR 1.23, 95% 95% CI 1.12-1.40), toluene (HR 1.20, 95% CI 1.00-1.38), benzene (HR 1.16, 95% CI 1.04-1.31), aromatic hydrocarbon solvents (HR 1...... of occupational exposure to trichloroethylene, perchloroethylene, aromatic hydrocarbon solvents, benzene and toluene and the risk of bladder cancer....

  3. Computer-Aided Solvent Screening for Biocatalysis

    DEFF Research Database (Denmark)

    Abildskov, Jens; Leeuwen, M.B. van; Boeriu, C.G.

    2013-01-01

    constrained properties related to chemical reaction equilibrium, substrate and product solubility, water solubility, boiling points, toxicity and others. Two examples are provided, covering the screening of solvents for lipase-catalyzed transesterification of octanol and inulin with vinyl laurate....... Esterification of acrylic acid with octanol is also addressed. Solvents are screened and candidates identified, confirming existing experimental results. Although the examples involve lipases, the method is quite general, so there seems to be no preclusion against application to other biocatalysts....

  4. Solvent management in a reprocessing plant

    International Nuclear Information System (INIS)

    Guillaume, B.; Germain, M.; Puyou, M.; Rouyer, H.

    1987-01-01

    Solvent management in large capacity reprocessing plant is studied to limit production of organic wastes. Chemical processing increases life time of solvent. Low pressure distillation allows the recycling of TBP and diluent at a low activity level. Besides heavy degradation products are eliminated. For the safety the flash point of distillated diluent increases slightly. Tests on an industrial scale started in 1985 and since more than 500 cubic meters were treated [fr

  5. Hazardous Solvent Substitution Data System reference manual

    International Nuclear Information System (INIS)

    Branham-Haar, K.A.; Twitchell, K.E.

    1993-07-01

    Concern for the environment, in addition to Federal regulation, mandate the replacement of hazardous solvents with safer cleaning agents. Manufacturers are working to produce these replacement solvents. As these products are developed, potential users need to be informed of their availability. To promote the use of these new products instead of traditional solvents, the Idaho National Engineering Laboratory (INEL) has developed the Hazardous Solvent Substitution Data System (HSSDS). The HSSDS provides a comprehensive system of information on alternatives to hazardous solvents and related subjects, and it makes that information available to solvent users, industrial hygienists, and process engineers. The HSSDS uses TOPIC reg-sign, a text retrieval system produced by Verity, Inc., to allow a user to search for information on a particular subject. TOPIC reg-sign produces a listing of the retrieved documents and allows the use to examine the documents individually and to use the information contained in them. This reference manual does not replace the comprehensive TOPIC reg-sign user documentation (available from Verity, Inc.), or the HSSDS Tutorial (available from the INEL). The purpose of this reference manual is to provide enough instruction on TOPIC reg-sign so the user may begin accessing the data contained in the HSSDS

  6. Adsorption of flexible polymer chains on a surface: Effects of different solvent conditions

    Science.gov (United States)

    Martins, P. H. L.; Plascak, J. A.; Bachmann, M.

    2018-05-01

    Polymer chains undergoing a continuous adsorption-desorption transition are studied through extensive computer simulations. A three-dimensional self-avoiding walk lattice model of a polymer chain grafted onto a surface has been treated for different solvent conditions. We have used an advanced contact-density chain-growth algorithm, in which the density of contacts can be directly obtained. From this quantity, the order parameter and its fourth-order Binder cumulant are computed, as well as the corresponding critical exponents and the adsorption-desorption transition temperature. As the number of configurations with a given number of surface contacts and monomer-monomer contacts is independent of the temperature and solvent conditions, it can be easily applied to get results for different solvent parameter values without the need of any extra simulations. In analogy to continuous magnetic phase transitions, finite-size-scaling methods have been employed. Quite good results for the critical properties and phase diagram of very long single polymer chains have been obtained by properly taking into account the effects of corrections to scaling. The study covers all solvent effects, going from the limit of super-self-avoiding walks, characterized by effective monomer-monomer repulsion, to poor solvent conditions that enable the formation of compact polymer structures.

  7. Optimization of Preparation Techniques for Poly(Lactic Acid-Co-Glycolic Acid) Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Birnbaum, Duane T.; Kosmala, Jacqueline D.; Brannon-Peppas, Lisa [Biogel Technology, Inc. (United States)], E-mail: lisabp@biogeltech.com

    2000-06-15

    Microparticles and nanoparticles of poly(lactic acid-co-glycolic acid) (PLAGA) are excellent candidates for the controlled release of many pharmaceutical compounds because of their biodegradable nature. The preparation of submicron PLAGA particles poses serious challenges that are not necessarily present when preparing microparticles. We have evaluated several combinations of organic solvents and surfactants used in the formulation of PLAGA nanoparticles. Critical factors such as the ability to separate the nanoparticles from the surfactant, the ability to re-suspend the nanoparticles after freeze-drying, formulation yield and nanoparticle size were studied. The smallest particles were obtained using the surfactant/solvent combination of sodium dodecyl sulfate and ethyl acetate (65 nm) and the largest particles were obtained using poly(vinyl alcohol) and dichloromethane (466 nm). However, the optimal nanoparticles were produced using either acetone or ethyl acetate as the organic solvent and poly(vinyl alcohol) or human serum albumin as the surfactant. This is because the most critical measure of performance of these nanoparticles proved to be their ability to re-suspend after freeze-drying.

  8. Optimization of Preparation Techniques for Poly(Lactic Acid-Co-Glycolic Acid) Nanoparticles

    International Nuclear Information System (INIS)

    Birnbaum, Duane T.; Kosmala, Jacqueline D.; Brannon-Peppas, Lisa

    2000-01-01

    Microparticles and nanoparticles of poly(lactic acid-co-glycolic acid) (PLAGA) are excellent candidates for the controlled release of many pharmaceutical compounds because of their biodegradable nature. The preparation of submicron PLAGA particles poses serious challenges that are not necessarily present when preparing microparticles. We have evaluated several combinations of organic solvents and surfactants used in the formulation of PLAGA nanoparticles. Critical factors such as the ability to separate the nanoparticles from the surfactant, the ability to re-suspend the nanoparticles after freeze-drying, formulation yield and nanoparticle size were studied. The smallest particles were obtained using the surfactant/solvent combination of sodium dodecyl sulfate and ethyl acetate (65 nm) and the largest particles were obtained using poly(vinyl alcohol) and dichloromethane (466 nm). However, the optimal nanoparticles were produced using either acetone or ethyl acetate as the organic solvent and poly(vinyl alcohol) or human serum albumin as the surfactant. This is because the most critical measure of performance of these nanoparticles proved to be their ability to re-suspend after freeze-drying

  9. Optimization of Preparation Techniques for Poly(Lactic Acid-Co-Glycolic Acid) Nanoparticles

    Science.gov (United States)

    Birnbaum, Duane T.; Kosmala, Jacqueline D.; Brannon-Peppas, Lisa

    2000-06-01

    Microparticles and nanoparticles of poly(lactic acid-co-glycolic acid) (PLAGA) are excellent candidates for the controlled release of many pharmaceutical compounds because of their biodegradable nature. The preparation of submicron PLAGA particles poses serious challenges that are not necessarily present when preparing microparticles. We have evaluated several combinations of organic solvents and surfactants used in the formulation of PLAGA nanoparticles. Critical factors such as the ability to separate the nanoparticles from the surfactant, the ability to re-suspend the nanoparticles after freeze-drying, formulation yield and nanoparticle size were studied. The smallest particles were obtained using the surfactant/solvent combination of sodium dodecyl sulfate and ethyl acetate (65 nm) and the largest particles were obtained using poly(vinyl alcohol) and dichloromethane (466 nm). However, the optimal nanoparticles were produced using either acetone or ethyl acetate as the organic solvent and poly(vinyl alcohol) or human serum albumin as the surfactant. This is because the most critical measure of performance of these nanoparticles proved to be their ability to re-suspend after freeze-drying.

  10. Analysis of solvent extracts from coal liquefaction in a flowing solvent reactor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wen-Ying; Feng, Jie; Xie, Ke-Chang [Key Laboratory of Coal Science and Technology, Taiyuan University of Technology, Ministry of Education and Shanxi Province, No. 79 Yingze West Street, Taiyuan 030024 (China); Kandiyoti, R. [Department of Chemical Engineering and Chemical Technology, Imperial College, University of London, London SW7 2BY (United Kingdom)

    2004-10-15

    Point of Ayr coal has been extracted using three solvents, tetralin, quinoline and 1-methyl-2-pyrrolidinone (NMP) at two temperatures 350 and 450 C, corresponding approximately to before and after the onset of massive covalent bond scission by pyrolysis. The three solvents differ in solvent power and the ability to donate hydrogen atoms to stabilise free radicals produced by pyrolysis of the coal. The extracts were prepared in a flowing solvent reactor to minimise secondary thermal degradation of the primary extracts. Analysis of the pentane-insoluble fractions of the extracts was achieved by size exclusion chromatography, UV-fluorescence spectroscopy in NMP solvent and probe mass. With increasing extraction temperature, the ratio of the amount having big molecular weight to that having small molecular weight in tetralin extracts was increased; the tetralin extract yield increased from 12.8% to 75.9%; in quinoline, increasing extraction temperature did not have an effect on the molecular weight of products but there was a big increase in extract yield. The extracts in NMP showed the enhanced solvent extraction power at both temperatures, with a shift in the ratio of larger molecules to smaller molecules with increasing extraction temperature and with the highest conversion of Point of Ayr coal among these three solvents at both temperatures. Solvent adducts were detected in the tetralin and quinoline extracts by probe mass spectrometry; solvent products were formed from NMP at both temperatures.

  11. How Critical Is Critical Thinking?

    Science.gov (United States)

    Shaw, Ryan D.

    2014-01-01

    Recent educational discourse is full of references to the value of critical thinking as a 21st-century skill. In music education, critical thinking has been discussed in relation to problem solving and music listening, and some researchers suggest that training in critical thinking can improve students' responses to music. But what exactly is…

  12. Co-solvents transesterification of cotton seed oil into biodiesel: Effects of reaction conditions on quality of fatty acids methyl esters

    International Nuclear Information System (INIS)

    Alhassan, Y.; Kumar, N.; Bugaje, I.M.; Pali, H.S.; Kathkar, P.

    2014-01-01

    Highlights: • Using co-solvent systems reduce reaction time by 60%. • Only small volume of co-solvent is required to improve the process. • Greater than 90% yields were obtained within the first 10 min. • Physico-chemical and fuel properties of FAMEs were within standard limits. • Acetone was found to be the best co-solvent for the transesterification. - Abstract: Solvent Technology, is gaining the interest of researchers in improving transesterification process recently. Transesterification of cotton seed oil into biodiesel using different mixtures of methanol with Diethyl Ether (DEE), Dichlorobenzene (CBN) or Acetone (ACT) co-solvent systems was conducted. Potassium hydroxide (KOH) was used as the catalyst all through. The reaction conditions optimized include; the molar ratio of co-solvent in methanol, reaction temperature and time. The catalyst concentration was also optimized. The optimization was based on the percentage yields of Fatty Acids Methyl Esters (FAMEs) produced. In addition, the effects of co-solvent systems on physico-chemical properties (Acid value and fatty acids composition) and fuel properties (viscosity, density and calorific value) were investigated as well. The result obtained, indicated 10% (v/v) addition of co-solvents CBN and ACT in methanol was the optimal volume. The optimal reaction temperature was 55 ° 0 C for 10 min when the catalyst concentration of 0.75% (w/w) weight of oil was used. Fuel properties were within the acceptable limit of ASTM and not significantly affected by the co-solvent systems except for the calorific value. It was concluded that the addition of co-solvent reduced the reaction time and improved some fuel properties of the biodiesel produced

  13. The A Priori Design and Selection of Ionic Liquids as Solvents for Active Pharmaceutical Ingredients

    DEFF Research Database (Denmark)

    Kunov-Kruse, Andreas Jonas; Weber, Cameron C.; Rogers, Robin D.

    2017-01-01

    In this paper we derive a straightforward computational approach to predict the optimal ionic liquid (IL) solvent for a given compound, based on COSMO-RS calculations. These calculations were performed on 18 different active pharmaceutical ingredients (APIs) using a matrix of 210 hypothetical ILs...... on the N-alkylguanidinium cation were prepared and characterized. The solubility of the APIs in each of these classes was found to be qualitatively consistent with the predictions of the COSMO-RS model. The suitability of these novel guanidinium salts as crystallization solvents was demonstrated by the use...

  14. Critical Jostling

    Directory of Open Access Journals (Sweden)

    Pippin Barr

    2016-11-01

    Full Text Available Games can serve a critical function in many different ways, from serious games about real world subjects to self-reflexive commentaries on the nature of games themselves. In this essay we discuss critical possibilities stemming from the area of critical design, and more specifically Carl DiSalvo’s adversarial design and its concept of reconfiguring the remainder. To illustrate such an approach, we present the design and outcomes of two games, Jostle Bastard and Jostle Parent. We show how the games specifically engage with two previous games, Hotline Miami and Octodad: Dadliest Catch, reconfiguring elements of those games to create interactive critical experiences and extensions of the source material. Through the presentation of specific design concerns and decisions, we provide a grounded illustration of a particular critical function of videogames and hope to highlight this form as another valuable approach in the larger area of videogame criticism.

  15. Determination of solvent concentration-dependent dispersion in the vapor extraction (VAPEX) process

    Energy Technology Data Exchange (ETDEWEB)

    Abukhalifeh, H.; Lohi, A.; Upreti, S. [Ryerson Polytechnic Univ., Toronto, ON (Canada)

    2008-07-01

    This paper presented the results of a computational algorithm that revealed the optimal conditions required for vapor extraction (VAPEX) for a solvent gas-heavy oil system. VAPEX is a promising recovery process because it requires low energy use and emits fewer greenhouse gases to the atmosphere compared to other enhanced oil recovery methods. The process is governed by the dispersion of solvent gases into heavy oil and bitumen. As such, it is essential to accurately determine solvent dispersion in VAPEX in order to effectively predict the amount and time scale of oil recovery, and to optimize field operations. VAPEX experiments were conducted in this study to determined the dispersion coefficient of a solvent as a function of its concentration in heavy oil and bitumen. The principles of variational calculus were used together with a mass transfer model of the experimental process. It was concluded that the oil production determined by the model should agree with its experimental counterpart, given the optimal gas dispersion versus concentration function.

  16. Lipase mediated synthesis of rutin fatty ester: Study of its process parameters and solvent polarity.

    Science.gov (United States)

    Vaisali, C; Belur, Prasanna D; Regupathi, Iyyaswami

    2017-10-01

    Lipophilization of antioxidants is recognized as an effective strategy to enhance solubility and thus effectiveness in lipid based food. In this study, an effort was made to optimize rutin fatty ester synthesis in two different solvent systems to understand the influence of reaction system hydrophobicity on the optimum conditions using immobilised Candida antartica lipase. Under unoptimized conditions, 52.14% and 13.02% conversion was achieved in acetone and tert-butanol solvent systems, respectively. Among all the process parameters, water activity of the system was found to show highest influence on the conversion in each reaction system. In the presence of molecular sieves, the ester production increased to 62.9% in tert-butanol system, unlike acetone system. Under optimal conditions, conversion increased to 60.74% and 65.73% in acetone and tert-butanol system, respectively. This study shows, maintaining optimal water activity is crucial in reaction systems having polar solvents compared to more non-polar solvents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Critical Proximity

    OpenAIRE

    Simon, Jane

    2010-01-01

    This essay considers how written language frames visual objects. Drawing on Michel Foucault’s response to Raymond Roussel’s obsessive description, the essay proposes a model of criticism where description might press up against its objects. This critical closeness is then mapped across the conceptual art practice and art criticism of Ian Burn. Burn attends to the differences between seeing and reading, and considers the conditions which frame how we look at images, including how w...

  18. Criticality Model

    International Nuclear Information System (INIS)

    Alsaed, A.

    2004-01-01

    The ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003) presents the methodology for evaluating potential criticality situations in the monitored geologic repository. As stated in the referenced Topical Report, the detailed methodology for performing the disposal criticality analyses will be documented in model reports. Many of the models developed in support of the Topical Report differ from the definition of models as given in the Office of Civilian Radioactive Waste Management procedure AP-SIII.10Q, ''Models'', in that they are procedural, rather than mathematical. These model reports document the detailed methodology necessary to implement the approach presented in the Disposal Criticality Analysis Methodology Topical Report and provide calculations utilizing the methodology. Thus, the governing procedure for this type of report is AP-3.12Q, ''Design Calculations and Analyses''. The ''Criticality Model'' is of this latter type, providing a process evaluating the criticality potential of in-package and external configurations. The purpose of this analysis is to layout the process for calculating the criticality potential for various in-package and external configurations and to calculate lower-bound tolerance limit (LBTL) values and determine range of applicability (ROA) parameters. The LBTL calculations and the ROA determinations are performed using selected benchmark experiments that are applicable to various waste forms and various in-package and external configurations. The waste forms considered in this calculation are pressurized water reactor (PWR), boiling water reactor (BWR), Fast Flux Test Facility (FFTF), Training Research Isotope General Atomic (TRIGA), Enrico Fermi, Shippingport pressurized water reactor, Shippingport light water breeder reactor (LWBR), N-Reactor, Melt and Dilute, and Fort Saint Vrain Reactor spent nuclear fuel (SNF). The scope of this analysis is to document the criticality computational method. The criticality

  19. 29 CFR 1915.32 - Toxic cleaning solvents.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Toxic cleaning solvents. 1915.32 Section 1915.32 Labor... Preservation § 1915.32 Toxic cleaning solvents. (a) When toxic solvents are used, the employer shall employ one or more of the following measures to safeguard the health of employees exposed to these solvents. (1...

  20. COMPUTER-AIDED SOLVENT DESIGN FOR POLLUTION PREVENTION: PARIS II

    Science.gov (United States)

    Solvent substitution is an attractive way of elijminating the use of regulated solvents because it usually does not require major chanages in existing processes, equipment or operations. Successful solvent substitution is dependent on finding solvents that are as effective or be...

  1. Optimization and Optimal Control

    CERN Document Server

    Chinchuluun, Altannar; Enkhbat, Rentsen; Tseveendorj, Ider

    2010-01-01

    During the last four decades there has been a remarkable development in optimization and optimal control. Due to its wide variety of applications, many scientists and researchers have paid attention to fields of optimization and optimal control. A huge number of new theoretical, algorithmic, and computational results have been observed in the last few years. This book gives the latest advances, and due to the rapid development of these fields, there are no other recent publications on the same topics. Key features: Provides a collection of selected contributions giving a state-of-the-art accou

  2. Optimally Stopped Optimization

    Science.gov (United States)

    Vinci, Walter; Lidar, Daniel

    We combine the fields of heuristic optimization and optimal stopping. We propose a strategy for benchmarking randomized optimization algorithms that minimizes the expected total cost for obtaining a good solution with an optimal number of calls to the solver. To do so, rather than letting the objective function alone define a cost to be minimized, we introduce a further cost-per-call of the algorithm. We show that this problem can be formulated using optimal stopping theory. The expected cost is a flexible figure of merit for benchmarking probabilistic solvers that can be computed when the optimal solution is not known, and that avoids the biases and arbitrariness that affect other measures. The optimal stopping formulation of benchmarking directly leads to a real-time, optimal-utilization strategy for probabilistic optimizers with practical impact. We apply our formulation to benchmark the performance of a D-Wave 2X quantum annealer and the HFS solver, a specialized classical heuristic algorithm designed for low tree-width graphs. On a set of frustrated-loop instances with planted solutions defined on up to N = 1098 variables, the D-Wave device is between one to two orders of magnitude faster than the HFS solver.

  3. New Polymeric Membranes for Organic Solvent Nanofiltration

    KAUST Repository

    Aburabie, Jamaliah

    2017-05-01

    The focus of this dissertation was the development, synthesis and modification of polymers for the preparation of membranes for organic solvent nanofiltration. High chemical stability in a wide range of solvents was a key requirement. Membranes prepared from synthesized polymers as well as from commercial polymers were designed and chemically modified to reach OSN requirements. A solvent stable thin-film composite (TFC) membrane is reported, which is fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate. The membranes exhibited high fluxes towards solvents like THF, DMF and DMSO ranging around 20 L/m2 h at 5 bar with a MWCO of around 1000 g/mol. Ultrafiltration PTSC membranes were prepared by non-solvent induced phase separation and crosslinked with GPTMS. The crosslinking reaction was responsible for the formation of an inorganic-type-network that tuned the membrane pore size. The crosslinked membranes acquired high solvent stability in DMSO, DMF and THF with a MWCO above 1300 g/mol. Reaction Induced Phase Separation (RIPS) was introduced as a new method for the preparation of skinned asymmetric membranes. These membranes have two distinctive layers with different morphologies both from the same polymer. The top dense layer is composed of chemically crosslinked polymer chains while the bottom layer is a porous structure formed by non-crosslinked polymer chains. Such membranes were tested for vitamin B12 in solvents after either crosslinking the support or dissolving the support and fixing the freestanding membrane on alumina. Pebax® 1657 was utilized for the preparation of composite membranes by simple coating. Porous PAN membranes were coated with Pebax® 1657 which was then crosslinked using TDI. Crosslinked Pebax® membranes show high stability towards ethanol, propanol and acetone. The membranes were also stable in DMF once crosslinked PAN supports were used. Sodium alginate polymer was investigated for the preparation of thin film composite

  4. Measurement and correlation of solubility of cefmenoxime hydrochloride in pure solvents and binary solvent mixtures

    International Nuclear Information System (INIS)

    Wang, Jinxiu; Xie, Chuang; Yin, Qiuxiang; Tao, Linggang; Lv, Jun; Wang, Yongli; He, Fang; Hao, Hongxun

    2016-01-01

    Highlights: • Solubility of cefmenoxime hydrochloride in pure and binary solvents was determined. • The experimental solubility data were correlated by thermodynamic models. • A model was employed to calculate the melting temperature of cefmenoxime hydrochloride. • Mixing thermodynamic properties of cefmenoxime hydrochloride were calculated. - Abstract: The solubility of cefmenoxime hydrochloride in pure solvents and binary solvent mixtures was measured at temperatures from (283.15 to 313.15) K by using the UV spectroscopic method. The results reveal that the solubility of cefmenoxime hydrochloride increases with increasing temperature in all solvent selected. The solubility of cefmenoxime hydrochloride reaches its maximum value when the mole fraction of isopropanol is 0.2 in the binary solvent mixtures of (isopropanol + water). The modified Apelblat equation and the NRTL model were successfully used to correlate the experimental solubility in pure solvents while the modified Apelblat equation, the CNIBS/R–K model and the Jouyban–Acree model were applied to correlate the solubility in binary solvent mixtures. In addition, the mixing thermodynamic properties of cefmenoxime hydrochloride in different solvents were also calculated based on the NRTL model and experimental solubility data.

  5. Solvent/non-solvent sintering: a novel route to create porous microsphere scaffolds for tissue regeneration.

    Science.gov (United States)

    Brown, Justin L; Nair, Lakshmi S; Laurencin, Cato T

    2008-08-01

    Solvent/non-solvent sintering creates porous polymeric microsphere scaffolds suitable for tissue engineering purposes with control over the resulting porosity, average pore diameter, and mechanical properties. Five different biodegradable biocompatible polyphosphazenes exhibiting glass transition temperatures from -8 to 41 degrees C and poly (lactide-co-glycolide), (PLAGA) a degradable polymer used in a number of biomedical settings, were examined to study the versatility of the process and benchmark the process to heat sintering. Parameters such as: solvent/non-solvent sintering solution composition and submersion time effect the sintering process. PLAGA microsphere scaffolds fabricated with solvent/non-solvent sintering exhibited an interconnected porosity and pore size of 31.9% and 179.1 mum, respectively which was analogous to that of conventional heat sintered PLAGA microsphere scaffolds. Biodegradable polyphosphazene microsphere scaffolds exhibited a maximum interconnected porosity of 37.6% and a maximum compressive modulus of 94.3 MPa. Solvent/non-solvent sintering is an effective strategy for sintering polymeric microspheres, with a broad spectrum of glass transition temperatures, under ambient conditions making it an excellent fabrication route for developing tissue engineering scaffolds and drug delivery vehicles. (c) 2007 Wiley Periodicals, Inc.

  6. Critical Optimism: Reimagining Rural Communities through Libraries

    Directory of Open Access Journals (Sweden)

    Margo Gustina

    2018-04-01

    Full Text Available In Brief: In the absence of governmental agencies and philanthropic support, many rural communities see their local library as the last civic, cultural, or service organization in town. This reality presents obvious challenges to the librarian, and also incredible opportunity. As the primary convener, libraries have the ability to facilitate regeneration in the communities they serve. This article situates rural librarianship within an organizing framework for change and discusses applications of community engagement tools and measures of impact aligned with social wellbeing.

  7. Solvent extraction studies in miniature centrifugal contactors

    International Nuclear Information System (INIS)

    Siczek, A.A.; Meisenhelder, J.H.; Bernstein, G.J.; Steindler, M.J.

    1980-01-01

    A miniature short-residence-time centrifugal solvent extraction contactor and an eight-stage laboratory minibank of centrifugal contactors were used for testing the possibility of utilizing kinetic effects for improving the separation of uranium from ruthenium and zirconium in the Purex process. Results of these tests showed that a small improvement found in ruthenium and zirconium decontamination in single-stage solvent extraction tests was lost in the multistage extraction tests- in fact, the extent of saturation of the solvent by uranium, rather than the stage residence time, controlled the extent of ruthenium and zirconium extraction. In applying the centrifugal contactor to the Purex process, the primary advantages would be less radiolytic damage to the solvent, high troughput, reduced solvent inventory, and rapid attainment of steady-state operating conditions. The multistage mini contactor was also tested to determine the suitability of short-residence-time contactors for use with the Civex and Thorex processes and was found to be compatible with the requirements of these processes. (orig.) [de

  8. Ions, solutes and solvents, oh my!

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Daniel David [Iowa State Univ., Ames, IA (United States)

    2009-08-01

    Modern methods in ab initio quantum mechanics have become efficient and accurate enough to study many gas-phase systems. However, chemists often work in the solution phase. The presence of solvent molecules has been shown to affect reaction mechanisms1, lower reaction energy barriers2, participate in energy transfer with the solute3 and change the physical properties of the solute4. These effects would be overlooked in simple gas phase calculations. Careful study of specific solvents and solutes must be done in order to fully understand the chemistry of the solution phase. Water is a key solvent in chemical and biological applications. The properties of an individual water molecule (a monomer) and the behavior of thousands of molecules (bulk solution) are well known for many solvents. Much is also understood about aqueous microsolvation (small clusters containing ten water molecules or fewer) and the solvation characteristics when bulk water is chosen to solvate a solute. However, much less is known about how these properties behave as the cluster size transitions from the microsolvated cluster size to the bulk. This thesis will focus on species solvated with water clusters that are large enough to exhibit the properties of the bulk but small enough to consist of fewer than one hundred solvent molecules. New methods to study such systems will also be presented.

  9. 40 CFR Table 5 to Subpart Qqqq of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for... HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the.... Solvent/solvent blend CAS. No. Average organic HAP mass fraction Typical organic HAP, percent by mass 1...

  10. 40 CFR Table 3 to Subpart IIIi of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for... Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the... Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical organic HAP, percent by mass 1...

  11. 40 CFR Table 4 to Subpart Oooo of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for... 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction... formulation data. Solvent/solvent blend CAS. No. Averageorganic HAP mass fraction Typical organic HAP, percent...

  12. Green solvents and technologies for oil extraction from oilseeds

    OpenAIRE

    Kumar, S. P. Jeevan; Prasad, S. Rajendra; Banerjee, Rintu; Agarwal, Dinesh K.; Kulkarni, Kalyani S.; Ramesh, K. V.

    2017-01-01

    Oilseeds are crucial for the nutritional security of the global population. The conventional technology used for oil extraction from oilseeds is by solvent extraction. In solvent extraction, n-hexane is used as a solvent for its attributes such as simple recovery, non-polar nature, low latent heat of vaporization (330?kJ/kg) and high selectivity to solvents. However, usage of hexane as a solvent has lead to several repercussions such as air pollution, toxicity and harmfulness that prompted to...

  13. Critical Review

    DEFF Research Database (Denmark)

    Rosenbaum, Ralph K.; Olsen, Stig Irving

    2018-01-01

    Manipulation and mistakes in LCA studies are as old as the tool itself, and so is its critical review. Besides preventing misuse and unsupported claims, critical review may also help identifying mistakes and more justifiable assumptions as well as generally improve the quality of a study. It thus...... supports the robustness of an LCA and increases trust in its results and conclusions. The focus of this chapter is on understanding what a critical review is, how the international standards define it, what its main elements are, and what reviewer qualifications are required. It is not the objective...... of this chapter to learn how to conduct a critical review, neither from a reviewer nor from a practitioner perspective. The foundation of this chapter and the basis for any critical review of LCA studies are the International Standards ISO 14040:2006, ISO 14044:2006 and ISO TS 14071:2014....

  14. Solvent engineering for high-quality perovskite solar cell with an efficiency approaching 20%

    Science.gov (United States)

    Wu, Tongyue; Wu, Jihuai; Tu, Yongguang; He, Xin; Lan, Zhang; Huang, Miaoliang; Lin, Jianming

    2017-10-01

    The perovskite layer is the most crucial factor for the high performance perovskite solar cells. Based on solvent engineering, we develop a ternary-mixed-solvent method for the growth of high-quality [Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3] cation-anion-mixed perovskite films by introducing N-methyl-2-pyrrolidone (NMP) into the precursor mixed solution. By controlling rapid nucleation and retarding crystal growth via intermediate phase PbI2-NMP (Lewis acid-base adduct), a dense, large grain, pinhole-free and long charge carrier lifetime perovskite film is obtained. By optimizing the precursor solvent composition, the perovskite solar cell achieves an impressive power conversion efficiency of 19.61% under one-sun illumination. The research presented here provides a facile, low-cost and highly efficient way for the preparation of perovskite solar cells.

  15. Influence of solvent on the morphology and microstructure of YSZ films obtained by spray pyrolysis technique

    International Nuclear Information System (INIS)

    Falcade, T.; Oliveira, G.B.; Mueller, I.L.; Malfatti, C.F.

    2010-01-01

    This work aims to investigate the influence of solvent used for the deposition of thin films of yttria stabilized zirconia (YSZ) on porous substrate. The films were obtained directly on the porous LSM substrate by spray pyrolysis technique, which consists of spraying a precursor solution containing salts of zirconium (Zr (C 6 H 7 O 2 ) 4) and yttrium (YCl 3 .6H 2 O), dissolved in specific solvents, on the heated substrate. The use of solvents with different boiling points and viscosity aims the optimization of experimental operating parameters to obtain homogeneous and dense films suitable for application as electrolyte in fuel cells, solid oxide (SOFC). The films were characterized by scanning electron microscopy, infrared spectroscopy and X-ray diffraction. (author)

  16. Biodiesel production by direct transesterification of microalgal biomass with co-solvent.

    Science.gov (United States)

    Zhang, Yan; Li, Ya; Zhang, Xu; Tan, Tianwei

    2015-11-01

    In this study, a direct transesterification process using 75% ethanol and co-solvent was studied to reduce the energy consumption of lipid extraction process and improve the conversion yield of the microalgae biodiesel. The addition of a certain amount of co-solvent (n-hexane is most preferable) was required for the direct transesterification of microalgae biomass. With the optimal reaction condition of n-hexane to 75% ethanol volume ratio 1:2, mixed solvent dosage 6.0mL, reaction temperature 90°C, reaction time 2.0h and catalyst volume 0.6mL, the direct transesterification process of microalgal biomass resulted in a high conversion yield up to 90.02±0.55wt.%. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Alternative Solvents through Green Chemistry Project

    Science.gov (United States)

    Hintze, Paul E.; Quinn, Jacqueline

    2014-01-01

    Components in the aerospace industry must perform with accuracy and precision under extreme conditions, and surface contamination can be detrimental to the desired performance, especially in cases when the components come into contact with strong oxidizers such as liquid oxygen. Therefore, precision cleaning is an important part of a components preparation prior to utilization in aerospace applications. Current cleaning technologies employ a variety of cleaning agents, many of which are halogenated solvents that are either toxic or cause environmental damage. Thus, this project seeks to identify alternative precision cleaning solvents and technologies, including use of less harmful cleaning solvents, ultrasonic and megasonic agitation, low-pressure plasma cleaning techniques, and supercritical carbon dioxide extraction. Please review all data content found in the Public Data tab located at: https:techport.nasa.govview11697public

  18. Hazardous Solvent Substitution Data System tutorial

    International Nuclear Information System (INIS)

    Twitchell, K.E.; Skinner, N.L.

    1993-07-01

    This manual is the tutorial for the Hazardous Solvent Substitution Data System (HSSDS), an online, comprehensive system of information on alternatives to hazardous solvents and related subjects. The HSSDS data base contains product information, material safety data sheets, toxicity reports, usage reports, biodegradable data, product chemical element lists, and background information on solvents. HSSDS use TOPIC reg-sign to search for information based on a query defined by the user. TOPIC provides a full text retrieval of unstructured source documents. In this tutorial, a series of lessons is provided that guides the user through basic steps common to most queries performed with HSSDS. Instructions are provided for both window-based and character-based applications

  19. Analytical Methods for Cs-137 and Other Radionuclides in Solvent Samples

    International Nuclear Information System (INIS)

    Pennebaker, F.M.

    2002-01-01

    Accurate characterization of individual waste components is critical to ensure design and operation of effective treatment processes and compliance with waste acceptance criteria. Current elemental analysis of organic matrices consists of conversion of the organic sample to aqueous by digesting the sample, which is inadequate in many cases. Direct analysis of the organic would increase sensitivity and decrease contamination and analysis time. For this project, we evaluated an Aridus membrane-desolvation sample introduction system for the direct analysis of organic solvents by Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The desolvator-ICP-MS successfully analyzed solvent from the caustic-side solvent extraction (CSSX) process and tri-butyl phosphate (TBP) organic tank waste from F-canyon for a variety of elements. Detection limits for most elements were determined in the part per trillion (ppt) range. This technology should increase accuracy in support of SRTC activities involving CSSX and other site processes involving organic compounds

  20. The optimal extraction parameters and anti-diabetic activity of ...

    African Journals Online (AJOL)

    diabetic activity of FIBL on alloxan induced diabetic mice were studied. The optimal extraction parameters of FIBL were obtained by single factor test and orthogonal test, as follows: ethanol concentration 60 %, ratio of solvent to raw material 30 ...

  1. Prednisolone multicomponent nanoparticle preparation by aerosol solvent extraction system.

    Science.gov (United States)

    Moribe, Kunikazu; Fukino, Mika; Tozuka, Yuichi; Higashi, Kenjirou; Yamamoto, Keiji

    2009-10-01

    Prednisolone nanoparticles were prepared in the presence of a hydrophilic polymer and a surfactant by the aerosol solvent extraction system (ASES). A ternary mixture of prednisolone, polyethylene glycol (PEG), and sodium dodecyl sulfate (SDS) dissolved in methanol was sprayed through a nozzle into the reaction vessel filled with supercritical carbon dioxide. After the ASES process was repeated, precipitates of the ternary components were obtained by depressurizing the reaction vessel. When a methanolic solution of prednisolone/PEG 4000/SDS at a weight ratio of 1:6:2 was sprayed under the optimized ASES conditions, the mean particle size of prednisolone obtained after dispersing the precipitates in water was observed to be ca. 230 nm. Prednisolone nanoparticles were not obtained by the binary ASES process for prednisolone, in the presence of either PEG or SDS. Furthermore, ternary cryogenic cogrinding, as well as solvent evaporation, was not effective for the preparation of prednisolone nanoparticles. As the ASES process can be conducted under moderate temperature conditions, the ASES process that was applied to the ternary system appeared to be one of the most promising methods for the preparation of drug nanoparticles using the multicomponent system.

  2. Improvement of Soybean Oil Solvent Extraction through Enzymatic Pretreatment

    Directory of Open Access Journals (Sweden)

    F. V. Grasso

    2012-01-01

    Full Text Available The purpose of this study is to evaluate multienzyme hydrolysis as a pretreatment option to improve soybean oil solvent extraction and its eventual adaptation to conventional processes. Enzymatic action causes the degradation of the cell structures that contain oil. Improvements in terms of extraction, yield, and extraction rate are expected to be achieved. Soybean flakes and collets were used as materials and hexane was used as a solvent. Temperature, pH, and incubation time were optimized and diffusion coefficients were estimated for each solid. Extractions were carried out in a column, oil content was determined according to time, and a mathematical model was developed to describe the system. The optimum conditions obtained were pH 5.4, 38°C, and 9.7 h, and pH 5.8, 44°C, and 5.8h of treatment for flakes and collets, respectively. Hydrolyzed solids exhibited a higher yield. Diffusion coefficients were estimated between 10-11 and 10-10. The highest diffusion coefficient was obtained for hydrolyzed collets. 0.73 g oil/mL and 0.7 g oil/mL were obtained at 240 s in a column for collets and flakes, respectively. Hydrolyzed solids exhibited a higher yield. The enzymatic incubation accelerates the extraction rate and allows for higher yield. The proposed model proved to be appropriate.

  3. NMR spectroscopy using liquid crystal solvents

    CERN Document Server

    Emsley, JW

    2013-01-01

    NMR Spectroscopy using Liquid Crystal Solvents covers the importance of using a liquid crystal solvent in NMR to derive nuclear dipolar spin-spin coupling constants. This book is composed of ten chapters, and begins with a brief description of the features and benefits of liquid crystal in NMR spectroscopic analysis. The succeeding chapters deal with the mode of operation of nuclear spin Hamiltonian for partially oriented molecules and the analysis of NMR spectra of partially oriented molecules, as well as the determination of rigid molecule structure. These topics are followed by discussions

  4. Catalog solvent extraction: anticipate process adjustments

    International Nuclear Information System (INIS)

    Campbell, S.G.; Brass, E.A.; Brown, S.J.; Geeting, M.W.

    2008-01-01

    The Modular Caustic-Side Solvent Extraction Unit (MCU) utilizes commercially available centrifugal contactors to facilitate removal of radioactive cesium from highly alkaline salt solutions. During the fabrication of the contactor assembly, demonstrations revealed a higher propensity for foaming than was initially expected. A task team performed a series of single-phase experiments that revealed that the shape of the bottom vanes and the outer diameter of those vanes are key to the successful deployment of commercial contactors in the Caustic-Side Solvent Extraction Process. (authors)

  5. Brownian motion of a nano-colloidal particle: the role of the solvent.

    Science.gov (United States)

    Torres-Carbajal, Alexis; Herrera-Velarde, Salvador; Castañeda-Priego, Ramón

    2015-07-15

    Brownian motion is a feature of colloidal particles immersed in a liquid-like environment. Usually, it can be described by means of the generalised Langevin equation (GLE) within the framework of the Mori theory. In principle, all quantities that appear in the GLE can be calculated from the molecular information of the whole system, i.e., colloids and solvent molecules. In this work, by means of extensive Molecular Dynamics simulations, we study the effects of the microscopic details and the thermodynamic state of the solvent on the movement of a single nano-colloid. In particular, we consider a two-dimensional model system in which the mass and size of the colloid are two and one orders of magnitude, respectively, larger than the ones associated with the solvent molecules. The latter ones interact via a Lennard-Jones-type potential to tune the nature of the solvent, i.e., it can be either repulsive or attractive. We choose the linear momentum of the Brownian particle as the observable of interest in order to fully describe the Brownian motion within the Mori framework. We particularly focus on the colloid diffusion at different solvent densities and two temperature regimes: high and low (near the critical point) temperatures. To reach our goal, we have rewritten the GLE as a second kind Volterra integral in order to compute the memory kernel in real space. With this kernel, we evaluate the momentum-fluctuating force correlation function, which is of particular relevance since it allows us to establish when the stationarity condition has been reached. Our findings show that even at high temperatures, the details of the attractive interaction potential among solvent molecules induce important changes in the colloid dynamics. Additionally, near the critical point, the dynamical scenario becomes more complex; all the correlation functions decay slowly in an extended time window, however, the memory kernel seems to be only a function of the solvent density. Thus, the

  6. A whiff of death: fatal volatile solvent inhalation abuse.

    Science.gov (United States)

    Steffee, C H; Davis, G J; Nicol, K K

    1996-09-01

    Inhalation abuse of volatile solvents, previously known generically as "glue sniffing," is typically pursued by adolescents. A wide range of legal, easily obtained products containing volatile substances are available for abuse. We report two illustrative cases of fatal volatile substance abuse: gasoline sniffing in a 20-year-old man and aerosol propellant gas inhalation (aerosol air freshener) in a 16-year-old girl with underlying reactive airway disease. Although the ratio of deaths to nonfatal inhalation escapades is extremely low, volatile solvent abuse carries the risk of sudden death due to cardiac arrest after a dysrhythmia or vasovagal event, central nervous system respiratory depression, hypoxia and hypercapnia due to the techniques of inhalation, and other mechanisms. Investigation of the patient's substance abuse history, examination of the scene of death, and special toxicologic analyses are critical to identifying volatile substance inhalation abuse as the cause of death because anatomic autopsy findings will typically be nonspecific. Above all, physicians must suspect the diagnosis of volatile substance inhalation abuse, especially in any case of sudden death involving an otherwise healthy young person.

  7. Superinsulating Polyisocyanate Based Aerogels: A Targeted Search for the Optimum Solvent System.

    Science.gov (United States)

    Zhu, Zhiyuan; Snellings, Geert M B F; Koebel, Matthias M; Malfait, Wim J

    2017-05-31

    Polyisocyanate based aerogels combine ultralow thermal conductivities with better mechanical properties than silica aerogel, but these properties critically depend on the nature of the gelation solvent, perhaps more so than on any other parameter. Here, we present a systematic study of the relationship between the polyurethane-polyisocyanurate (PUR-PIR) aerogel microstructure, surface area, thermal conductivity, and density and the gelation solvent's Hansen solubility parameters for an industrially relevant PUR-PIR rigid foam formulation. We first investigated aerogels prepared in acetone-dimethyl sulfoxide (DMSO) blends and observed a minimum in thermal conductivity (λ) and maximum in specific surface area for an acetone:DMSO ratio of 85:15 v/v. We then prepared PUR-PIR aerogels in 32 different solvent blends, divided into three series with δ Dispersion , δ Polarity , and δ H-bonding fixed at 15.94, 11.30, and 7.48 MPa 1/2 , respectively, corresponding to the optimum parameters for the acetone:DMSO series. The aerogel properties display distinct dependencies on the various solubility parameters: aerogels with low thermal conductivity can be synthesized in solvents with a high δ H-bonding parameter (above 7.2) and δ Dispersion around 16.3 MPa 1/2 . In contrast, the δ Polarity parameter is of lesser importance. Our study highlights the importance of the gelation solvent, clarifies the influence of the different solvent properties, and provides a methodology for a targeted search across the solvent chemical space based on the Hansen solubility parameters.

  8. Investigations on the role of mixed-solvent for improved efficiency in perovskite solar cell

    Science.gov (United States)

    Singh, Ranbir; Suranagi, Sanjaykumar R.; Kumar, Manish; Shukla, Vivek Kumar

    2017-12-01

    The morphology of the spin-coated photoactive layer is one of the major factors affecting the performance of perovskite solar cells. In this work, we have employed a mixed-solvent strategy to obtain a high quality MAPbI3 (MA = CH3NH3) perovskite film, without pinholes and reduced grain boundaries. Perovskite films formed with single and mixed-solvents are systematically characterized for their optical, structural, and morphological properties using UV-vis absorption, photoluminescence (PL), X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) tools. The power conversion efficiency (PCE) of the devices fabricated using the mixed-solvent showed better performance than the devices made using the single solvent. The best-optimized mixed-solvent perovskite film exhibited a PCE of 15.2% with uniform film coverage on the substrate, better charge generation, and a high hole mobility of 1.16 × 10-4cm2/V s. The disparities in photovoltaic properties have been analyzed with the intensity dependent current density-voltage (J-V), transient photovoltage (TPV), and relationship between photocurrent (Jph) and effective voltage (Veff).

  9. Purification of Drug Loaded PLGA Nanoparticles Prepared by Emulsification Solvent Evaporation Using Stirred Cell Ultrafiltration Technique.

    Science.gov (United States)

    Paswan, Suresh K; Saini, T R

    2017-12-01

    The emulsifiers in an exceedingly higher level are used in the preparation of drug loaded polymeric nanoparticles prepared by emulsification solvent evaporation method. This creates great problem to the formulator due to their serious toxicities when it is to be administered by parenteral route. The final product is therefore required to be freed from the used surfactants by the conventional purification techniques which is a cumbersome job. The solvent resistant stirred cell ultrafiltration unit (Millipore) was used in this study using polyethersulfone ultrafiltration membrane (Biomax®) having pore size of NMWL 300 KDa as the membrane filter. The purification efficiency of this technique was compared with the conventional centrifugation technique. The flow rate of ultrafiltration was optimized for removal of surfactant (polyvinyl alcohol) impurities to the acceptable levels in 1-3.5 h from the nanoparticle dispersion of tamoxifen prepared by emulsification solvent evaporation method. The present investigations demonstrate the application of solvent resistant stirred cell ultrafiltration technique for removal of toxic impurities of surfactant (PVA) from the polymeric drug nanoparticles (tamoxifen) prepared by emulsification solvent evaporation method. This technique offers added benefit of producing more concentrated nanoparticles dispersion without causing significant particle size growth which is observed in other purification techniques, e.g., centrifugation and ultracentrifugation.

  10. Critical Arts

    African Journals Online (AJOL)

    both formal and informal) in culture and social theory. CRITICAL ARTS aims to challenge and ... Book Review: Brian McNair, An Introduction to Political Communication (3rd edition), London: Routledge, 2003, ISBN 0415307082, 272pp. Phil Joffe ...

  11. Critical Proximity

    Directory of Open Access Journals (Sweden)

    Jane Simon

    2010-09-01

    Full Text Available This essay considers how written language frames visual objects. Drawing on Michel Foucault’s response to Raymond Roussel’s obsessive description, the essay proposes a model of criticism where description might press up against its objects. This critical closeness is then mapped across the conceptual art practice and art criticism of Ian Burn. Burn attends to the differences between seeing and reading, and considers the conditions which frame how we look at images, including how we look at, and through words. The essay goes on to consider Meaghan Morris’s writing on Lynn Silverman’s photographs. Both Morris and Burn offer an alternative to a parasitic model of criticism and enact a patient way of looking across and through visual landscapes.

  12. Critical proximity

    Directory of Open Access Journals (Sweden)

    Simon, Jane

    2010-01-01

    Full Text Available This essay considers how written language frames visual objects. Drawing on Michel Foucault’s response to Raymond Roussel’s obsessive description, the essay proposes a model of criticism where description might press up against its objects. This critical closeness is then mapped across the conceptual art practice and art criticism of Ian Burn. Burn attends to the differences between seeing and reading, and considers the conditions which frame how we look at images, including how we look at, and through words. The essay goes on to consider Meaghan Morris’s writing on Lynn Silverman’s photographs. Both Morris and Burn offer an alternative to a parasitic model of criticism and enact a patient way of looking across and through visual landscapes.

  13. Morin-based nanofiltration membranes for organic solvent separation processes

    KAUST Repository

    Perez Manriquez, Liliana

    2018-02-26

    In this work we demonstrate the successful optimization of the interfacial polymerization reaction for the manufacture of organic solvent nanofiltration membranes by replacing the toxic amines commonly used for this method with the natural occurring bio-polyphenol morin. For the manufacture of this type of OSN membrane a crosslinked PAN support was coated by interfacial polymerization using morin as the monomer of the aqueous phase and terephtaloyl chloride as the monomer of the organic phase. These membranes showed an exceptional performance and resistance to NMP by having a a permeance of 0.3L/m2 h bar in NMP with a rejection of 96% of Brilliant Blue dye which has a molecular weight of 825.97g/mol, making these membranes attractive for harsh industrial separation processes due to their ease of manufacture, low cost, and excellent performance.

  14. Next Generation Solvent Performance in the Modular Caustic Side Solvent Extraction Process - 15495

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Tara E. [Savannah River Remediation, LLC., Aiken, SC (United States); Scherman, Carl [Savannah River Remediation, LLC., Aiken, SC (United States); Martin, David [Savannah River Remediation, LLC., Aiken, SC (United States); Suggs, Patricia [Savannah River Site (SRS), Aiken, SC (United States)

    2015-01-14

    Changes to the Modular Caustic Side Solvent Extraction Unit (MCU) flow-sheet were implemented in the facility. Implementation included changing the scrub and strip chemicals and concentrations, modifying the O/A ratios for the strip, scrub, and extraction contactor banks, and blending the current BoBCalixC6 extractant-based solvent in MCU with clean MaxCalix extractant-based solvent. During the successful demonstration period, the MCU process was subject to rigorous oversight to ensure hydraulic stability and chemical/radionuclide analysis of the key process tanks (caustic wash tank, solvent hold tank, strip effluent hold tank, and decontaminated salt solution hold tank) to evaluate solvent carryover to downstream facilities and the effectiveness of cesium removal from the liquid salt waste. Results indicated the extraction of cesium was significantly more effective with an average Decontamination Factor (DF) of 1,129 (range was 107 to 1,824) and that stripping was effective. The contactor hydraulic performance was stable and satisfactory, as indicated by contactor vibration, contactor rotational speed, and flow stability; all of which remained at or near target values. Furthermore, the Solvent Hold Tank (SHT) level and specific gravity was as expected, indicating that solvent integrity and organic hydraulic stability were maintained. The coalescer performances were in the range of processing results under the BOBCalixC6 flow sheet, indicating negligible adverse impact of NGS deployment. After the Demonstration period, MCU began processing via routine operations. Results to date reiterate the enhanced cesium extraction and stripping capability of the Next Generation Solvent (NGS) flow sheet. This paper presents process performance results of the NGS Demonstration and continued operations of MCU utilizing the blended BobCalixC6-MaxCalix solvent under the NGS flowsheet.

  15. Greening Reversed-Phase Liquid Chromatography Methods Using Alternative Solvents for Pharmaceutical Analysis

    Directory of Open Access Journals (Sweden)

    Moussa Yabré

    2018-05-01

    Full Text Available The greening of analytical methods has gained increasing interest in the field of pharmaceutical analysis to reduce environmental impacts and improve the health safety of analysts. Reversed-phase high-performance liquid chromatography (RP-HPLC is the most widely used analytical technique involved in pharmaceutical drug development and manufacturing, such as the quality control of bulk drugs and pharmaceutical formulations, as well as the analysis of drugs in biological samples. However, RP-HPLC methods commonly use large amounts of organic solvents and generate high quantities of waste to be disposed, leading to some issues in terms of ecological impact and operator safety. In this context, greening HPLC methods is becoming highly desirable. One strategy to reduce the impact of hazardous solvents is to replace classically used organic solvents (i.e., acetonitrile and methanol with greener ones. So far, ethanol has been the most often used alternative organic solvent. Others strategies have followed, such as the use of totally aqueous mobile phases, micellar liquid chromatography, and ionic liquids. These approaches have been well developed, as they do not require equipment investments and are rather economical. This review describes and critically discusses the recent advances in greening RP-HPLC methods dedicated to pharmaceutical analysis based on the use of alternative solvents.

  16. A sparse autoencoder-based deep neural network for protein solvent accessibility and contact number prediction.

    Science.gov (United States)

    Deng, Lei; Fan, Chao; Zeng, Zhiwen

    2017-12-28

    Direct prediction of the three-dimensional (3D) structures of proteins from one-dimensional (1D) sequences is a challenging problem. Significant structural characteristics such as solvent accessibility and contact number are essential for deriving restrains in modeling protein folding and protein 3D structure. Thus, accurately predicting these features is a critical step for 3D protein structure building. In this study, we present DeepSacon, a computational method that can effectively predict protein solvent accessibility and contact number by using a deep neural network, which is built based on stacked autoencoder and a dropout method. The results demonstrate that our proposed DeepSacon achieves a significant improvement in the prediction quality compared with the state-of-the-art methods. We obtain 0.70 three-state accuracy for solvent accessibility, 0.33 15-state accuracy and 0.74 Pearson Correlation Coefficient (PCC) for the contact number on the 5729 monomeric soluble globular protein dataset. We also evaluate the performance on the CASP11 benchmark dataset, DeepSacon achieves 0.68 three-state accuracy and 0.69 PCC for solvent accessibility and contact number, respectively. We have shown that DeepSacon can reliably predict solvent accessibility and contact number with stacked sparse autoencoder and a dropout approach.

  17. Criticality safety

    International Nuclear Information System (INIS)

    Walker, G.

    1983-01-01

    When a sufficient quantity of fissile material is brought together a self-sustaining neutron chain reaction will be started in it and will continue until some change occurs in the fissile material to stop the chain reaction. The quantity of fissile material required is the 'Critical Mass'. This is not a fixed quantity even for a given type of fissile material but varies between quite wide limits depending on a number of factors. In a nuclear reactor the critical mass of fissile material is assembled under well-defined condition to produce a controllable chain reaction. The same materials have to be handled outside the reactor in all stages of fuel element manufacture, storage, transport and irradiated fuel reprocessing. At any stage it is possible (at least in principle) to assemble a critical mass and thus initiate an accidental and uncontrollable chain reaction. Avoiding this is what criticality safety is all about. A system is just critical when the rate of production of neutrons balances the rate of loss either by escape or by absorption. The factors affecting criticality are, therefore, those which effect neutron production and loss. The principal ones are:- type of nuclide and enrichment (or isotopic composition), moderation, reflection, concentration (density), shape and interaction. Each factor is considered in detail. (author)

  18. Controlling Actinide Hydration in Mixed Solvent Systems: Towards Tunable Solvent Systems to Close the Fuel Cycle

    International Nuclear Information System (INIS)

    Clark, Sue B.

    2016-01-01

    The goal of this project has been to define the extent of hydration the f-elements and other cations in mixed solvent electrolyte systems. Methanol-water and other mixed solvent systems have been studied, where the solvent dielectric constant was varied systematically. Thermodynamic and spectroscopic studies provide details concerning the energetics of complexation and other reactions of these cations. This information has also been used to advance new understanding of the behavior of these cations in a variety of systems, ranging from environmental studies, chromatographic approaches, and ionization processes for mass spectrometry.

  19. Controlling Actinide Hydration in Mixed Solvent Systems: Towards Tunable Solvent Systems to Close the Fuel Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Sue B. [Washington State Univ., Pullman, WA (United States). Dept. of Chemistry

    2016-10-31

    The goal of this project has been to define the extent of hydration the f-elements and other cations in mixed solvent electrolyte systems. Methanol-water and other mixed solvent systems have been studied, where the solvent dielectric constant was varied systematically. Thermodynamic and spectroscopic studies provide details concerning the energetics of complexation and other reactions of these cations. This information has also been used to advance new understanding of the behavior of these cations in a variety of systems, ranging from environmental studies, chromatographic approaches, and ionization processes for mass spectrometry.

  20. Influence of electrolyte ion-solvent interactions on the performances of supercapacitors porous carbon electrodes

    Science.gov (United States)

    Decaux, C.; Matei Ghimbeu, C.; Dahbi, M.; Anouti, M.; Lemordant, D.; Béguin, F.; Vix-Guterl, C.; Raymundo-Piñero, E.

    2014-10-01

    The development of advanced and safe electrochemical supercapacitors or hybrid supercapacitors combining a battery electrode material such as graphite and a porous carbon electrode implies the use of new electrolytes containing a tetra-alkylammonium or lithium salt dissolved preferentially in a safe and environmentally friendly solvent such as alkylcarbonates. In those systems, the carbon porosity of the activated carbon electrode controls the electrochemical behavior of the whole device. In this work, it is demonstrated that electrolytes containing highly polarizing ions such as Li+ dissolved in polar solvents such as alkylcarbonates do not completely loss their solvation shell at the opposite of what is observed for poorly solvated cations like TEABF4. As a consequence, the optimal carbon pore size for obtaining the largest energy density, while keeping a high power density, is wider when strongly solvated cations, like Li+ are used than for conventional organic electrolytes using acetonitrile as solvent and TEA+ as salt cations. TEA+ cations are easily desolvated and hence are able to penetrate in small pores matching the dimensions of bare ions. The dissimilarity of behavior of alkylcarbonates and acetonitrile based electrolytes highlights the importance of ion-solvent interactions when searching the optimal porous texture for the electrode material.

  1. An organic solvent-, detergent-, and thermo-stable alkaline protease from the mesophilic, organic solvent-tolerant Bacillus licheniformis 3C5.

    Science.gov (United States)

    Rachadech, W; Navacharoen, A; Ruangsit, W; Pongtharangkul, T; Vangnai, A S

    2010-01-01

    Bacillus licheniformis 3C5, isolated as mesophilic bacterium, exhibited tolerance towards a wide range of non-polar and polar organic solvents at 45 degrees C. It produced an extracellular organic solvent-stable protease with an apparent molecular mass of approximately 32 kDa. The inhibitory effect of PMSF and EDTA suggested it is likely to be an alkaline serine protease. The protease was active over abroad range of temperatures (45-70 degrees C) and pH (8-10) range with an optimum activity at pH 10 and 65 degrees C. It was comparatively stable in the presence ofa relatively high concentration (35% (v/v)) of organic solvents and various types of detergents even at a relatively high temperature (45 degrees C). The protease production by B. licheniformis 3C5 was growth-dependent. The optimization of carbon and nitrogen sources for cell growth and protease production revealed that yeast extract was an important medium component to support both cell growth and the protease production. The overall properties of the protease produced by B. licheniformis 3C5 suggested that this thermo-stable, solvent-stable, detergent-stable alkaline protease is a promising potential biocatalyst for industrial and environmental applications.

  2. Optimization with Extremal Dynamics

    International Nuclear Information System (INIS)

    Boettcher, Stefan; Percus, Allon G.

    2001-01-01

    We explore a new general-purpose heuristic for finding high-quality solutions to hard discrete optimization problems. The method, called extremal optimization, is inspired by self-organized criticality, a concept introduced to describe emergent complexity in physical systems. Extremal optimization successively updates extremely undesirable variables of a single suboptimal solution, assigning them new, random values. Large fluctuations ensue, efficiently exploring many local optima. We use extremal optimization to elucidate the phase transition in the 3-coloring problem, and we provide independent confirmation of previously reported extrapolations for the ground-state energy of ±J spin glasses in d=3 and 4

  3. Solvent-tolerant bacteria in biocatalysis.

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1998-01-01

    The toxicity of fine chemicals to the producer organism is a problem in several biotechnological production processes. In several instances, an organic phase can be used to extract the toxic product from the aqueous phase during a fermentation. With the discovery of solvent-tolerant bacteria, more

  4. SHORT COMMUNICATION SOLVENT FREE PREPARATION OF N ...

    African Journals Online (AJOL)

    Preferred Customer

    KEYWORDS: Solvent free, Maleanilic acids, Maleic anhydride, Aniline derivatives ... associated with the carboxylic group between 3275-2877 cm-1, the weak –NH .... Chemical shifts (σ/ppm) relative to TMS*. O-H N-H Ha. Hb. Hc. Hd. He. Hf.

  5. Simulation of solvent extraction in reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Shekhar; Koganti, S B [Reprocessing Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    1994-06-01

    A SIMulation Program for Solvent EXtraction (SIMPSEX) has been developed for simulation of PUREX process used in nuclear fuel reprocessing. This computer program is written in double precision structured FORTRAN77 and at present it is used in DOS environment on a PC386. There is a plan to port it to ND supermini computers in future. (author). 5 refs., 3 figs.

  6. Deposition dynamics of multi-solvent bioinks

    Science.gov (United States)

    Kaneelil, Paul; Pack, Min; Cui, Chunxiao; Han, Li-Hsin; Sun, Ying

    2017-11-01

    Inkjet printing cellular scaffolds using bioinks is gaining popularity due to the advancement of printing technology as well as the growing demands of regenerative medicine. Numerous studies have been conducted on printing scaffolds of biomimetic structures that support the cell production of human tissues. However, the underlying physics of the deposition dynamics of bioinks remains elusive. Of particular interest is the unclear deposition dynamics of multi-solvent bioinks, which is often used to tune the micro-architecture formation. Here we systematically studied the effects of jetting frequency, solvent properties, substrate wettability, and temperature on the three-dimensional deposition patterns of bioinks made of Methacrylated Gelatin and Carboxylated Gelatin. The microflows inside the inkjet-printed picolitre drops were visualized using fluorescence tracer particles to decipher the complex processes of multi-solvent evaporation and solute self-assembly. The evolution of droplet shape was observed using interferometry. With the integrated techniques, the interplay of solvent evaporation, biopolymer deposition, and multi-drop interactions were directly observed for various ink and substrate properties, and printing conditions. Such knowledge enables the design and fabrication of a variety of tissue engineering scaffolds for potential use in regenerative medicine.

  7. Double Solvent for Extracting Rare Earth Concentrate

    International Nuclear Information System (INIS)

    Bintarti, AN; Bambang EHB

    2007-01-01

    An extraction process to rare earth concentrate which contain elements were yttrium (Y), lanthanum (La), cerium (Ce), neodymium (Nd), samarium (Sm), gadolinium (Gd) and dysprosium (Dy) which were dissolved in to nitric acid has been done. The experiment of the extraction by double solvent in batch to mix 10 ml of the feed with 10 ml solvent contained the pair of solvent was TBP and TOA, D2EHPA and TOA, TBP and D2EHPA in cyclohexane as tinner. It was selected a right pairs of solvent for doing variation such as the acidity of the feed from 2 - 6 M and the time of stirring from 5 - 25 minutes gave the good relatively extraction condition to Dy element such as using 10 % volume of TOA in D2EHPA and cyclohexane, the acidity of the feed 3 M and the time stirring 15 minutes produced coefficient distribution to dysprosium = 0.586 and separation factor Dy-Ce = ∼ (unlimited); Dy-Nd = 4.651. (author)

  8. Dynamics of solvent-free grafted nanoparticles

    KAUST Repository

    Chremos, Alexandros; Panagiotopoulos, Athanassios Z.; Koch, Donald L.

    2012-01-01

    as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent

  9. Solvent (acetone-butanol: ab) production

    Science.gov (United States)

    This article describes production of butanol [acetone-butanol-ethanol, (also called AB or ABE or solvent)] by fermentation using both traditional and current technologies. AB production from agricultural commodities, such as corn and molasses, was an important historical fermentation. Unfortunately,...

  10. Processing of thermoplastic polymers using reactive solvents

    NARCIS (Netherlands)

    Meijer, H.E.H.; Venderbosch, R.W.; Goossens, J.G.P.; Lemstra, P.J.

    1996-01-01

    The use of reactive solvents offers an interesting and flexible route to extent the processing characteristics of thermoplastic polymers beyond their existing limits. This holds for both intractable and tractable polymers. The first mainly applies for amorphous high-Tg polymers where processing may

  11. Mixed Solvent Reactive Recrystallization of Sodium Carbonate

    NARCIS (Netherlands)

    Gaertner, R.S.

    2005-01-01

    Investigation of the reactive recrystallization of trona (sodium sesquicarbonate) and sodium bicarbonate to sodium carbonate (soda) in a mixed solvent led to the design of several alternative, less energy consumptive, economically very attractive process routes for the production of soda from all

  12. Nitrogen critical loads using biodiversity-related critical limits

    International Nuclear Information System (INIS)

    Posch, Maximilian; Aherne, Julian; Hettelingh, Jean-Paul

    2011-01-01

    Critical loads are widely used in the effects-based assessment of emission reduction policies. While the impacts of acidification have diminished, there is increasing concern regarding the effects of nitrogen deposition on terrestrial ecosystems. In this context much attention has been focussed on empirical critical loads as well as simulations with linked geochemistry-vegetation models. Surprisingly little attention has been paid to adapt the widely used simple mass balance approach. This approach has the well-established benefit of easy regional applicability, while incorporating specified critical chemical criteria to protect specified receptors. As plant occurrence/biodiversity is related to both the nutrient and acidity status of an ecosystem, a single abiotic factor (chemical criterion) is not sufficient. Rather than an upper limit for deposition (i.e., critical load), linked nutrient nitrogen and acidity chemical criteria for plant occurrence result in an 'optimal' nitrogen and sulphur deposition envelope. - Highlights: → Mass balance critical load approaches for nutrient nitrogen remain useful. → Biodiversity-related limits are related to nutrient and acidity status. → Nutrient and acidity chemical criteria lead to optimal deposition envelopes. → Optimal loads support effects-based emission reduction policies. - Biodiversity-related critical limits lead to optimal nitrogen and sulphur deposition envelopes for plant species or species compositions.

  13. Gas separation by composite solvent-swollen membranes

    Science.gov (United States)

    Matson, Stephen L.; Lee, Eric K. L.; Friesen, Dwayne T.; Kelly, Donald J.

    1989-01-01

    There is disclosed a composite immobulized liquid membrane of a solvent-swollen polymer and a microporous organic or inorganic support, the solvent being at least one highly polar solvent containing at least one nitrogen, oxygen, phosphorous or sulfur atom, and having a boiling point of at least 100.degree. C. and a specified solubility parameter. The solvent or solvent mixture is homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. The membrane is suitable for acid gas scrubbing and oxygen/nitrogen separation.

  14. Gas separation by composite solvent-swollen membranes

    Science.gov (United States)

    Matson, S.L.; Lee, E.K.L.; Friesen, D.T.; Kelly, D.J.

    1989-04-25

    There is disclosed a composite immobilized liquid membrane of a solvent-swollen polymer and a microporous organic or inorganic support, the solvent being at least one highly polar solvent containing at least one nitrogen, oxygen, phosphorus or sulfur atom, and having a boiling point of at least 100 C and a specified solubility parameter. The solvent or solvent mixture is homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. The membrane is suitable for acid gas scrubbing and oxygen/nitrogen separation. 3 figs.

  15. The Critical Micelle Concentration of Asphaltenes as Measured by Calorimetry

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Christensen, S. D.

    2000-01-01

    Micellization of asphaltenes in solution has been investigated using a micro calorimetric titration procedure (Andersen, S. I.; Birdi, K. S. J Colloid Interface Sci. 1991, 142, 497). The method uses the analysis of heat of dissociation and dilution of asphaltene micelles when a pure solvent (or...... solvent mixture) is titrated with a solution of asphaltene in the same solvent. The asphaltene concentration of the injected solution is at a level above the critical micelle concentration (CMC). In the present paper the procedure is applied in investigation of asphaltenes as well as subfractions...

  16. How Critical Is Critical Infrastructure?

    Science.gov (United States)

    2015-09-01

    manager conducting a risk self-assessment will likely be subconsciously biased to assess greater risks than actually exist. This problem can be... bias .” The optimism bias extends beyond MBA students. People under estimate their risk for car accidents, think the chances of divorce are low, and...Decisions about Health, Wealth, and Happiness (New Haven, CT: Yale University Press, 2008), 20. 29 others.80 Optimism bias is evident in compulsive

  17. Solubility of daidzin in different organic solvents and (ethyl alcohol + water) mixed solvents

    International Nuclear Information System (INIS)

    Fan, Jie-Ping; Yang, Dan; Xu, Xiao-Kang; Guo, Xiao-Jie; Zhang, Xue-Hong

    2015-01-01

    Highlights: • The solubilities of daidzin were measured in various solvents. • The solubility data were correlated by three models. • The thermodynamic properties of the dissolution process were also determined. - Abstract: The solubility of daidzin in different organic solvents and (ethyl alcohol + water) mixed solvents was measured by high performance liquid chromatography (HPLC) analysis method from T = (283.2 to 323.2) K at atmosphere pressure. The results show that at higher temperature more daidzin dissolves, and moreover, the solubility increases with the ethyl alcohol mole fraction increase in the (ethyl alcohol + water) mixed solvents. The experimental solubility values were correlated by a simplified thermodynamic equation, λh equation and modified Apelblat equation. Based on the solubility of daidzin, the enthalpy and entropy of solution were also evaluated by van’t Hoff equation. The results illustrated that the dissolution process of daidzin is endothermic and entropy driven

  18. Micellization behaviour and thermodynamic parameters of 12-2-12 gemini surfactant in (water + organic solvent) mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Batigoec, Cigdem [Department of Chemistry, Faculty of Sciences, Trakya University, 22030 Edirne (Turkey); Akbas, Halide, E-mail: hakbas34@yahoo.com [Department of Chemistry, Faculty of Sciences, Trakya University, 22030 Edirne (Turkey); Boz, Mesut [Department of Chemistry, Faculty of Sciences, Trakya University, 22030 Edirne (Turkey)

    2011-09-15

    Highlights: > The cmc and {alpha} values of surfactant increased with increasing solvent content and temperature. > The values of ({Delta}G{sub m}{sup 0}) are negative in all cases for the micelle formation becomes less favourable. > The values of negative enthalpy indicate importance of the London dispersion forces for the micellization. > The positive entropy is due to a contribution supplied from the solvent. - Abstract: The effect of organic solvents on micellization behaviour and thermodynamic parameters of a cationic gemini (dimeric) surfactant, C{sub 12}H{sub 25}(CH{sub 3}){sub 2}N{sup +}-(CH{sub 2}){sub 2}-N{sup +}(CH{sub 3}){sub 2}C{sub 12}H{sub 25}.2Br{sup -}, (12-2-12) was studied in aqueous solutions over the range of T = (293.15 to 323.15) K using the conductometric technique. Ethylene glycol (EG), dimethylsulfoxide (DMSO) and 1,4-dioxan (DO) were used as organic solvents with three different contents. The critical micelle concentration (cmc) and the degree of counter ion dissociation ({alpha}) of micelles in the water and in the (water + organic solvent) mixtures including 10%, 20%, and 30% solvent contents were determined. The standard Gibbs free energy ({Delta}G{sub m}{sup 0}), enthalpy ({Delta}H{sub m}{sup 0}) and entropy ({Delta}S{sub m}{sup 0}) of micellization were estimated from the temperature dependence of the cmc values. It was observed that the critical micelle concentration of the gemini surfactant and the degree of counter ion dissociation of the micelle increased as the volume percentage of organic solvent, and temperature increased. The standard Gibbs free energy of micellization was found to be less negative with the increase in the organic solvent content and temperature.

  19. Justification of the solvent choice for the industrial amizon substance production

    Directory of Open Access Journals (Sweden)

    V. A. Georgiyants

    2014-08-01

    solvents as the most similar in their properties and acceptable cost, we considered for possible use in industrial amizone production. In the first phase the solubility of the intermediate (Bink and amizone in these solvents were studied. It was found that substance was very slightly soluble in cold organic solvents and was easily soluble in boiling. Water adding to these solvents in various ratios significantly improved solubility, and the best solubility, as expected, had water. To justify the choice of solvents for the first and second stage of the synthesis and crystallization an experimental study of the efficacy of using ethanol, acetone and 2-propanol in various processes of synthesis was done. Thus the yield of final product was evaluated and the amount of associated impurities before and after crystallization was measured. It was proved that at the synthesis stage it is expedient to use 2-propanol and as crystallization solvent – ethanol. CONCLUSIONS 1. Experimental studies for the justification for the choice of solvent for the industrial synthesis of isonicotinic acid benzylamide iodomethylate substance considering QbD concepts and classes of toxic solvents were done. 2. It was established that in the synthesis is optimal to use 2-propanol and for crystallization - ethanol.

  20. Biodiesel production from ethanolysis of palm oil using deep eutectic solvent (DES) as co-solvent

    Science.gov (United States)

    Manurung, R.; Winarta, A.; Taslim; Indra, L.

    2017-06-01

    Biodiesel produced from ethanolysis is more renewable and have better properties (higher oxidation stability, lower cloud and pour point) compared to methanolysis, but it has a disadvantage such as complicated purification. To improve ethanolysis process, deep eutectic solvent (DES) can be prepared from choline chloride and glycerol and used as co-solvent in ethanolysis. The deep eutectic solvent is formed from a quaternary ammonium salt (choline chloride) and a hydrogen bond donor (Glycerol), it is a non-toxic, biodegradable solvent compared to a conventional volatile organic solvent such as hexane. The deep eutectic solvent is prepared by mixing choline chloride and glycerol with molar ratio 1:2 at temperature 80 °C, stirring speed 300 rpm for 1 hour. The DES is characterized by its density and viscosity. The ethanolysis is performed at a reaction temperature of 70 °C, ethanol to oil molar ratio of 9:1, potassium hydroxide as catalyst concentration of 1.2 wt. DES as co-solvent with concentration 0.5 to 3 wt. stirring speed 400 rpm, and a reaction time 1 hour. The obtained biodiesel is then characterized by its density, viscosity, and ester content. The oil - ethanol phase condition is observed in the reaction tube. The oil - ethanol phase with DES tends to form meniscus compared to without DES, showed that oil and ethanol become more slightly miscible, which favors the reaction. Using DES as co-solvent in ethanolysis showed increasing in yield and easier purification. The esters properties meet the international standards ASTM D6751, with the highest yield achieved 83,67 with 99,77 conversion at DES concentration 2 . Increasing DES concentration above 2 in ethanolysis decrease the conversion and yield, because of the excessive glycerol in the systems makes the reaction equilibrium moves to the reactant side.

  1. Computer-aided tool for solvent selection in pharmaceutical processes: Solvent swap

    DEFF Research Database (Denmark)

    Papadakis, Emmanouil; K. Tula, Anjan; Gernaey, Krist V.

    -liquid equilibria). The application of the developed model-based framework is highlighted through several cases studies published in the literature. In the current state, the framework is suitable for problems where the original solvent is exchanged by distillation. A solvent selection guide for fast of suitable......-aided framework with the objective to assist the pharmaceutical industry in gaining better process understanding. A software interface to improve the usability of the tool has been created also....

  2. Optimization by simulation of the coupling between a sub-critical reactor and its spallation source. Towards a pilot reactor; Optimisation par simulation du couplage entre un reacteur sous-critique et sa source de spallation. Application a un demonstrateur

    Energy Technology Data Exchange (ETDEWEB)

    Kerdraon, D

    2001-10-01

    Accelerator Driven Systems (ADS), based on a proton accelerator and a sub-critical core coupled with a spallation target, offer advantages in order to reduce the nuclear waste radiotoxicity before repository closure. Many studies carried out on the ADS should lead to the definition of an experimental plan which would federate the different works in progress. This thesis deals with the neutronic Monte Carlo simulations with the MCNPX code to optimize such a system in view of a pilot reactor building. First, we have recalled the main neutronic properties of an hybrid reactor. The concept of gas-cooled eXperimental Accelerator Driven System (XADS) chosen for our investigations comes from the preliminary studies done by the Framatome company. In order to transmute minor actinides, we have considered the time evolution of the main fuels which could be reasonably used for the demonstration phases. The neutronic parameters of the reactor, concerning minor actinide transmutation, are reported. Also, we have calculated the characteristic times and the transmutation rates in the case of {sup 99}Tc and {sup 129}I isotopes. We have identified some neutronic differences between an experimental and a power ADS according to the infinite multiplication coefficient, the shape factor and the level of flux to extend the demonstrator concept. We have proposed geometric solutions to keep the radial shape factor of a power ADS acceptable. In the last part, beyond the experimental XADS scope, we have examined the possible transition towards an uranium/thorium cycle based on Molten Salt Reactors using a power ADS in order to generate the required {sup 233}U proportion. (author)

  3. Linear correlation of interfacial tension at water-solvent interface, solubility of water in organic solvents, and SE* scale parameters

    International Nuclear Information System (INIS)

    Mezhov, E.A.; Khananashvili, N.L.; Shmidt, V.S.

    1988-01-01

    A linear correlation has been established between the solubility of water in water-immiscible organic solvents and the interfacial tension at the water-solvent interface on the one hand and the parameters of the SE* and π* scales for these solvents on the other hand. This allows us, using the known tabulated SE* or π* parameters for each solvent, to predict the values of the interfacial tension and the solubility of water for the corresponding systems. We have shown that the SE* scale allows us to predict these values more accurately than other known solvent scales, since in contrast to other scales it characterizes solvents found in equilibrium with water

  4. Protection efficacy of gloves against components of the solvent in a sprayed isocyanate coating utilizing a reciprocating permeation panel.

    Science.gov (United States)

    Ceballos, Diana M; Reeb-Whitaker, Carolyn; Sasakura, Miyoko; Dills, Russell; Yost, Michael G

    2015-04-01

    Determine protection effectiveness of 5-mil natural rubber latex (0.13-mm), 5-mil nitrile rubber (0.13-mm), and 13-mil butyl rubber (0.33-mm) glove materials against solvents present in a commonly used automotive clear coat formulation using a novel permeation panel. The latex and nitrile gloves were the type commonly used by local autobody spray painters. Glove materials were tested by spraying an automotive clear coat onto an automated reciprocating permeation panel (permeation panel II). Temperature, relative humidity, and spray conditions were controlled to optimize clear coat loading homogeneity as evaluated by gravimetric analysis. Solvent permeation was measured using charcoal cloth analyzed by the National Institute for Occupational Safety and Health 1501 method. Natural rubber latex allowed 3-5 times the permeation of solvents relative to nitrile rubber for all 10 solvents evaluated: ethyl benzene, 2-heptanone, 1-methoxy-2-propyl acetate, o-xylene, m-xylene, p-xylene, n-butyl acetate, methyl isobutyl ketone, petroleum distillates, and toluene. There is a distinct behavior in solvent permeation before and after the coating dry time. Solvent permeation increased steadily before coating dry time and remained fairly constant after coating dry time. Butyl was not permeated by any of the solvents under the conditions tested. Commonly used 5-mil thick (0.13-mm) latex and nitrile gloves were ineffective barriers to solvents found in a commonly used clear coat formulation. Conversely, 13-mil (0.33-mm) butyl gloves were found to be protective against all solvents in the clear coat formulation. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  5. Effects of solvent evaporation conditions on solvent vapor annealed cylinder-forming block polymer thin films

    Science.gov (United States)

    Grant, Meagan; Jakubowski, William; Nelson, Gunnar; Drapes, Chloe; Baruth, A.

    Solvent vapor annealing is a less time and energy intensive method compared to thermal annealing, to direct the self-assembly of block polymer thin films. Periodic nanostructures have applications in ultrafiltration, magnetic arrays, or other structures with nanometer dimensions, driving its continued interest. Our goal is to create thin films with hexagonally packed, perpendicular aligned cylinders of poly(lactide) in a poly(styrene) matrix that span the thickness of the film with low anneal times and low defect densities, all with high reproducibility, where the latter is paramount. Through the use of our computer-controlled, pneumatically-actuated, purpose-built solvent vapor annealing chamber, we have the ability to monitor and control vapor pressure, solvent concentration within the film, and solvent evaporation rate with unprecedented precision and reliability. Focusing on evaporation, we report on two previously unexplored areas, chamber pressure during solvent evaporation and the flow rate of purging gas aiding the evaporation. We will report our exhaustive results following atomic force microscopy analysis of films exposed to a wide range of pressures and flow rates. Reliably achieving well-ordered films, while occurring within a large section of this parameter space, was correlated with high-flow evaporation rates and low chamber pressures. These results have significant implications on other methods of solvent annealing, including ``jar'' techniques.

  6. STAR POLYMERS IN GOOD SOLVENTS FROM DILUTE TO CONCENTRATED REGIMES: CROSSOVER APPROACH

    Directory of Open Access Journals (Sweden)

    S.B.Kiselev

    2002-01-01

    Full Text Available An introduction is given to the crossover theory of the conformational and thermodynamic properties of star polymers in good solvents. The crossover theory is tested against Monte Carlo simulation data for the structure and thermodynamics of model star polymers. In good solvent conditions, star polymers approach a "universal" limit as N → ∞, however, there are two types of approach towards this limit. In the dilute regime, a critical degree of polymerization N* is found to play a similar role as the Ginzburg number in the crossover theory for critical phenomena in simple fluids. A rescaled penetration function is found to control the free energy of star polymer solutions in the dilute and semidilute regions. This equation of state captures the scaling behaviour of polymer solutions in the dilute/semidilute regimes and also performs well in the concentrated regimes, where the details of the monomer-monomer interactions become important.

  7. The Effect of Acetone Amount Ratio as Co-Solvent to Methanol in Transesterification Reaction of Waste Cooking Oil

    Science.gov (United States)

    Julianto, T. S.; Nurlestari, R.

    2018-04-01

    The production of biodiesel from waste cooking oil by transesterification reaction using acetone as co-solvent has been carried out. This research studied the optimal amount ratio of acetone as co-solvent to methanol in the transesterification process using homogeneous alkaline catalyst KOH 1% (w/w) of waste cooking oil at room temperature for 15 minutes of reaction time. Mole ratio of waste cooking oil to methanol is 1:12. Acetone was added as co-solvent in varied amount ratio to methanol are 1:4, 1:2, and 1:1, respectively. The results of fatty acid methyl esters (FAME) were analysed using GC-MS instrument. The results showed that the optimal ratio is 1:4 with 99.93% of FAME yield.

  8. Method for Predicting Solubilities of Solids in Mixed Solvents

    DEFF Research Database (Denmark)

    Ellegaard, Martin Dela; Abildskov, Jens; O'Connell, J. P.

    2009-01-01

    A method is presented for predicting solubilities of solid solutes in mixed solvents, based on excess Henry's law constants. The basis is statistical mechanical fluctuation solution theory for composition derivatives of solute/solvent infinite dilution activity coefficients. Suitable approximatio...

  9. Thin porphyrin composite membranes with enhanced organic solvent transport

    KAUST Repository

    Phuoc, Duong; Anjum, Dalaver H.; Peinemann, Klaus-Viktor; Nunes, Suzana Pereira

    2018-01-01

    Extending the stability of polymeric membranes in organic solvents is important for applications in chemical and pharmaceutical industry. Thin-film composite membranes with enhanced solvent permeance are proposed, using porphyrin as a building block

  10. Effects of polar protic solvents on dual emissions of 3 ...

    Indian Academy of Sciences (India)

    TECS

    Figure 1. Scheme of the ESIPT reaction of 3-hydroxy- chromone, 1. Chart 1. Chemical structures of the studied ... Materials and methods. Absorption and ... 85. Table 1. Spectroscopic properties of 3HC dyes in different polar solvents.a. Solvent.

  11. Selection and Evaluation of Alternative Solvents for Caprolactam Extraction

    NARCIS (Netherlands)

    van Delden, M.L.; Kuipers, N.J.M.; de Haan, A.B.

    2006-01-01

    Because of the strict legislation for currently applied solvents in the industrial extraction of caprolactam, being benzene, toluene and chlorinated hydrocarbons, a need exists for alternative, environmentally benign solvents. An experimental screening procedure consisting of several steps was used

  12. Selection and evaluation of alternative solvents for caprolactam extraction

    NARCIS (Netherlands)

    Delden, van M.L.; Kuipers, N.J.M.; Haan, de A.B.

    2006-01-01

    Because of the strict legislation for currently applied solvents in the industrial extraction of caprolactam, being benzene, toluene and chlorinated hydrocarbons, a need exists for alternative, environmentally benign solvents. An experimental screening procedure consisting of several steps was used

  13. Occupational exposure to chlorinated and petroleum solvents and mycosis fungoides

    DEFF Research Database (Denmark)

    Morales-Suárez-Varela, Maria M; Olsen, Jørn; Villeneuve, Sara

    2013-01-01

    To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF).......To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF)....

  14. Organic Solvent Tropical Report [SEC 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    COWLEY, W.L.

    2000-06-21

    This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an unmitigated organic solvent fire is within risk evaluation guidelines.

  15. Structural transition of a homopolymer in solvents mixture

    Energy Technology Data Exchange (ETDEWEB)

    Guettari, Moez [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunisia (Tunisia)], E-mail: gtarimoez@yahoo.fr; Aschi, Adel; Gomati, Riadh; Gharbi, Abdelhafidh [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunisia (Tunisia)

    2008-07-01

    The present work is aimed at studying the thermodynamic behaviour of a polymer in solvents mixture. Dynamic light scattering is used to measure the hydrodynamic radius of polyvinylpyrrolidone (M{sub w} = 360,000 g/mol), in water/methanol solvents mixture, versus the mixed solvents composition at 25 deg. C. Then, we show that the polymer conformation adopts the Coil-Globule-Coil structure when the methanol molar fraction X{sub A} is varied. This transition is attributed to solvent quality change which result from water and methanol complex formation. The polymer contraction rate calculated for each composition takes its maximum value at X{sub A} = 0.17. Hildebrand theory assuming the solvents mixture as an equivalent solvent was used to analyze the change in mixed solvents quality. These changes can be attributed to dispersive forces in solvents mixture.

  16. Structural transition of a homopolymer in solvents mixture

    International Nuclear Information System (INIS)

    Guettari, Moez; Aschi, Adel; Gomati, Riadh; Gharbi, Abdelhafidh

    2008-01-01

    The present work is aimed at studying the thermodynamic behaviour of a polymer in solvents mixture. Dynamic light scattering is used to measure the hydrodynamic radius of polyvinylpyrrolidone (M w = 360,000 g/mol), in water/methanol solvents mixture, versus the mixed solvents composition at 25 deg. C. Then, we show that the polymer conformation adopts the Coil-Globule-Coil structure when the methanol molar fraction X A is varied. This transition is attributed to solvent quality change which result from water and methanol complex formation. The polymer contraction rate calculated for each composition takes its maximum value at X A = 0.17. Hildebrand theory assuming the solvents mixture as an equivalent solvent was used to analyze the change in mixed solvents quality. These changes can be attributed to dispersive forces in solvents mixture

  17. Chemical engineering aspect of solvent extraction in mineral processing

    International Nuclear Information System (INIS)

    Dara, S.S.; Jakkikar, M.S.

    1975-01-01

    Solvent extraction process, types of solvents used, types of extraction, distribution isotherm and McCabe-Thiele diagram for process design, equipment for the process, operating parameters and applications are described. (M.G.B.)

  18. A solvent/non-solvent system for achieving solution-processed multilayer organic light-emitting devices

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yue; Wu, Zhaoxin, E-mail: zhaoxinwu@mail.xjtu.edu.cn; He, Lin; Jiao, Bo; Hou, Xun

    2015-08-31

    We developed a solvent/non-solvent system to fabricate the multilayer organic light-emitting devices (OLEDs) based on poly(N-vinylcarbazole) (PVK) by solution-process. This solvent system consists of both the solvent and non-solvent of PVK, in which fluorescent small molecules could be fully dissolved and directly spin-coated on top of the PVK layer; it could effectively avoid the redissolution of PVK during the spin-coating process of small molecules emitting layer. In the further investigation of this system, we also demonstrated the three-component solvent system, and found out that the third component, a less volatile solvent of PVK, was crucial for preparing a smoother interface between PVK and emitting layer. Compared with OLEDs through the vacuum deposition, the devices fabricated by solution-process from the solvent/non-solvent system showed comparable efficiency, which indicate that the solvent/non-solvent system can be used as an alternative process to prepare the polymer and small molecule multilayer devices through all-solution-process. - Highlights: • We fabricate the multilayer OLEDs by solution-process using a novel system. • We develop a solvent/non-solvent system of polymer (PVK) to avoid redissolution. • Small molecules could be fully dissolved and directly spin-coated on PVK layer. • The devices fabricated by the system and vacuum deposition show comparable efficiency.

  19. Critical Vidders

    DEFF Research Database (Denmark)

    Svegaard, Robin Sebastian Kaszmarczyk

    2015-01-01

    This article will introduce and take a look at a specific subset of the fan created remix videos known as vids, namely those that deal with feminist based critique of media. Through examples, it will show how fans construct and present their critique, and finally broach the topic of the critical ...

  20. Total Inventory of Selected Radionuclides in Old Solvent Tanks S1 Through S22

    International Nuclear Information System (INIS)

    Leyba, J.D.

    2001-01-01

    The total inventory of fourteen radionuclides, three metals, and volatile organic compounds (VOCs) has been calculated for the twenty-two Old Solvent Tanks (OSTs). The inventory calculations are based upon extensive characterization data of the multiple liquid and sludge samples taken from the OSTs. In addition, the total inventory of sixteen actinides (including error) has been calculated. The actinide inventory will be useful for criticality safety considerations

  1. Sensibilidade do carrapato Boophilus microplus a solventes Sensibility of Boophilus microplus tick to solvents

    Directory of Open Access Journals (Sweden)

    Ana Carolina de Souza Chagas

    2003-02-01

    Full Text Available Os experimentos envolvendo o uso de acaricidas sintéticos ou naturais, geralmente necessitam da utilização de um solvente. Com a finalidade de verificar a sensibilidade do carrapato bovino Boophilus microplus a diferentes solventes, larvas e fêmeas ingurgitadas deste ectoparasito foram expostas a sete solventes em cinco diferentes concentrações, na ausência e presença de azeite de oliva. Os resultados mostraram que a utilização do azeite de oliva não produz resultados diferentes estatisticamente em testes de larvas com papel impregnado, fato não verificado em testes de imersão de adultos com compostos hidrofílicos. A mortalidade média causada pelos solventes foi menor nos testes com papel impregnado, aumentando nos testes de imersão de larvas e de adultos. Solventes de baixo peso molecular e pouca viscosidade como o álcool metílico e o álcool etílico, não interferiram na mortalidade média em testes biológicos de B. microplus, principalmente em concentrações inferiores a 76%.Experiments carried out with synthetic or natural acaricides usually use a solvent. To investigate the sensitivity of Boophilus microplus cattle tick to different solvents, larvae and engorged female were subjected to seven solvents in five different concentrations. It was done in the presence and absence of olive oil. The results showed that the utilization of olive oil doesn't produce different statistical results in impregnated paper larvae test. It did not happen in adults immersion test with hydrophilic compounds. The mean mortality caused by solvents was small in impregnated paper larvae test, increasing in immersion tests of larvae and adults. Solvents with low molecular weight and viscosity like ethyl alcohol and methyl alcohol did not cause interference in the mortality of B. microplus in biological tests, mainly in concentrations below 76%.

  2. Myoglobin solvent structure at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, B.V.; Korszun, Z.R. [Brookhaven National Laboratory, Upton, NY (United States); Schoenborn, B.P. [Los Alamos National Laboratory, NM (United States)

    1994-12-31

    The structure of the solvent surrounding myoglobin crystals has been analyzed using neutron diffraction data, and the results indicate that the water around the protein is not disordered, but rather lies in well-defined hydration shells. We have analyzed the structure of the solvent surrounding the protein by collecting neutron diffraction data at four different temperatures, namely, 80, 130, 180, and 240K. Relative Wilson Statistics applied to low resolution data showed evidence of a phase transition in the region of 180K. A plot of the liquidity factor, B{sub sn}, versus distance from the protein surface begins with a high plateau near the surface of the protein and drops to two minima at distances from the protein surface of about 2.35{Angstrom} and 3.85{Angstrom}. Two distinct hydration shells are observed. Both hydration shells are observed to expand as the temperature is increased.

  3. Extracting solid carbonaceous materials with solvents

    Energy Technology Data Exchange (ETDEWEB)

    1936-02-08

    Solvent extraction of solid carbonaceous materials is performed in the presence of powdered catalysts together with alkaline substances. Oxides of nickel or iron or nickel nitrate have been used together with caustic soda or potash solutions or milk of lime. Solvents used include benzenes, middle oils, tars, tetrahydronaphthalene. The extraction is performed at 200 to 500/sup 0/C under pressures of 20 to 200 atm. Finely ground peat was dried and mixed with milk of lime and nickel nitrate and an equal quantity of middle oil. The mixture was heated for 3 h at 380/sup 0/C at 90 atm. 88.5% of the peat was extracted. In a similar treatment brown coal was impregnated with solutions of caustic soda and ferric chloride.

  4. Measuring solvent barrier properties of paper

    International Nuclear Information System (INIS)

    Bollström, Roger; Saarinen, Jarkko J; Toivakka, Martti; Räty, Jukka

    2012-01-01

    New methods for measuring barrier properties against solvents, acids and bases on dispersion coated paper were developed and investigated. Usability, reliability and repeatability were compared both between the new methods and with the standardized method for measuring barrier properties against water vapor. Barrier properties could be measured with all methods and the results obtained by the different methods were in correlation with each other. A qualitative method based on a trace color provided an indicative result, whereas further developed methods also took into account the durability. The effective barrier lifetime could be measured by measuring the conductivity through the substrate as a function of time, or by utilizing a glass prism where the change in refractive index caused by penetrated liquid was monitored, also as a function of time. Barrier properties against water and humidity were also measured and were found not to be predictors for barrier properties against either solvents, or acids or bases, which supports the need to develop new methods

  5. Solvent-extraction purification of neptunium

    International Nuclear Information System (INIS)

    Kyser, E.A.; Hudlow, S.L.

    2008-01-01

    The Savannah River Site (SRS) has recovered 237 Np from reactor fuel that is currently being processed into NpO 2 for future production of 238 Pu. Several purification flowsheets have been utilized. An oxidizing solvent-extraction (SX) flowsheet was used to remove Fe, sulfate ion, and Th while simultaneously 237 Np, 238 Pu, u, and nonradioactive Ce(IV) was extracted into the tributyl phosphate (TBP) based organic solvent. A reducing SX flowsheet (second pass) removed the Ce and Pu and recovered both Np and U. The oxidizing flowsheet was necessary for solutions that contained excessive amounts of sulfate ion. Anion exchange was used to perform final purification of Np from Pu, U, and various non-actinide impurities. The Np(IV) in the purified solution was then oxalate-precipitated and calcined to an oxide for shipment to other facilities for storage and future target fabrication. Performance details of the SX purification and process difficulties are discussed. (authors)

  6. Myoglobin solvent structure at different temperatures

    International Nuclear Information System (INIS)

    Daniels, B.V.; Korszun, Z.R.; Schoenborn, B.P.

    1994-01-01

    The structure of the solvent surrounding myoglobin crystals has been analyzed using neutron diffraction data, and the results indicate that the water around the protein is not disordered, but rather lies in well-defined hydration shells. We have analyzed the structure of the solvent surrounding the protein by collecting neutron diffraction data at four different temperatures, namely, 80, 130, 180, and 240K. Relative Wilson Statistics applied to low resolution data showed evidence of a phase transition in the region of 180K. A plot of the liquidity factor, B sn , versus distance from the protein surface begins with a high plateau near the surface of the protein and drops to two minima at distances from the protein surface of about 2.35 Angstrom and 3.85 Angstrom. Two distinct hydration shells are observed. Both hydration shells are observed to expand as the temperature is increased

  7. The disposal of radioactive solvent waste

    International Nuclear Information System (INIS)

    Dean, B.; Baker, W.T.

    1976-01-01

    As the use of radioisotope techniques increases, laboratories are faced with the problem of disposing of considerable quantities of organic solvent and aqueous liquid wastes. Incineration or collection by a waste contractor both raise problems. Since most of the radiochemicals are preferentially water soluble, an apparatus for washing the radiochemicals out into water and discharging into the normal drainage system in a high diluted form is described. Despite the disadvantages (low efficiency, high water usuage, loss of solvent in presence of surface active agents, precipitation of phosphors from dioxan based liquids) it is felt that the method has some merit if a suitably improved apparatus can be designed at reasonable cost. (U.K.)

  8. Catalytic coal liquefaction with treated solvent and SRC recycle

    Science.gov (United States)

    Garg, Diwakar; Givens, Edwin N.; Schweighardt, Frank K.

    1986-01-01

    A process for the solvent refining of coal to distillable, pentane soluble products using a dephenolated and denitrogenated recycle solvent and a recycled, pentane-insoluble, solvent-refined coal material, which process provides enhanced oil-make in the conversion of coal.

  9. Green solvents and technologies for oil extraction from oilseeds.

    Science.gov (United States)

    Kumar, S P Jeevan; Prasad, S Rajendra; Banerjee, Rintu; Agarwal, Dinesh K; Kulkarni, Kalyani S; Ramesh, K V

    2017-01-01

    Oilseeds are crucial for the nutritional security of the global population. The conventional technology used for oil extraction from oilseeds is by solvent extraction. In solvent extraction, n -hexane is used as a solvent for its attributes such as simple recovery, non-polar nature, low latent heat of vaporization (330 kJ/kg) and high selectivity to solvents. However, usage of hexane as a solvent has lead to several repercussions such as air pollution, toxicity and harmfulness that prompted to look for alternative options. To circumvent the problem, green solvents could be a promising approach to replace solvent extraction. In this review, green solvents and technology like aqueous assisted enzyme extraction are better solution for oil extraction from oilseeds. Enzyme mediated extraction is eco-friendly, can obtain higher yields, cost-effective and aids in obtaining co-products without any damage. Enzyme technology has great potential for oil extraction in oilseed industry. Similarly, green solvents such as terpenes and ionic liquids have tremendous solvent properties that enable to extract the oil in eco-friendly manner. These green solvents and technologies are considered green owing to the attributes of energy reduction, eco-friendliness, non-toxicity and non-harmfulness. Hence, the review is mainly focussed on the prospects and challenges of green solvents and technology as the best option to replace the conventional methods without compromising the quality of the extracted products.

  10. 40 CFR 52.254 - Organic solvent usage.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Organic solvent usage. 52.254 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.254 Organic solvent usage. (a) This... (d) of this section and the architectural coatings and solvent disposal emission limitations...

  11. 27 CFR 21.125 - Rubber hydrocarbon solvent.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Rubber hydrocarbon solvent. 21.125 Section 21.125 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....125 Rubber hydrocarbon solvent. (a) Rubber hydrocarbon solvent is a petroleum derivative. (b...

  12. Effect of Nd:YAG laser on the solvent evaporation of adhesive systems.

    Science.gov (United States)

    Batista, Graziela Ribeiro; Barcellos, Daphne Câmara; Rocha Gomes Torres, Carlos; Damião, Álvaro José; de Oliveira, Hueder Paulo Moisés; de Paiva Gonçalves, Sérgio Eduardo

    2015-01-01

    This study evaluated the influence of Nd:YAG laser on the evaporation degree (ED) of the solvent components in total-etch and self-etch adhesives. The ED of Gluma Comfort Bond (Heraeus-Kulzer) one-step self-etch adhesive, and Adper Single Bond 2 (3M ESPE), and XP Bond (Dentsply) total-etch adhesives was determined by weight alterations using two techniques: Control--spontaneous evaporation of the solvent for 5 min; Experimental--Nd:YAG laser irradiation for 1 min, followed by spontaneous evaporation for 4 min. The weight loss due to evaporation of the volatile components was measured at baseline and after 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, 110 s, 2 min, 3 min, 4 min, and 5 min. Evaporation of solvent components significantly increased with Nd:YAG laser irradiation for all adhesives investigated. Gluma Comfort Bond showed significantly higher evaporation of solvent components than Adper Single Bond 2 and XP Bond. All the adhesives lost weight quickly during the first min of Nd:YAG laser irradiation. The application of Nd:YAG laser on adhesives before light curing had a significant effect on the evaporation of the solvent components, and the ED of Gluma Comfort Bond one-step self-etch adhesive was significantly higher than with Adper Single Bond 2 and XP Bond total-etch adhesives. The use of the Nd:YAG laser on the uncured adhesive technique can promote a greater ED of solvents, optimizing the longevity of the adhesive restorations.

  13. Solvent extraction of Southern US tar sands

    Energy Technology Data Exchange (ETDEWEB)

    Penney, W.R.

    1990-01-01

    The Department of Chemical Engineering at the University of Arkansas, in association with Diversified Petroleum Recovery, Inc. (DPR) of Little Rock, Arkansas, has been developing a solvent extraction process for the recovery of bitumen from tar sands for the past five years. The unique feature of the process is that the bitumen is recovered from the solvent by contacting with a co-solvent, which causes the bitumen to precipitate. The overall purpose of this project is to study both the technical and economic feasibility of applying this technology for recovery of bitumen from tar sands by (1) investigating the socioeconmic factors which affect (a) plant siting and (b) the market value of recovered bitumen; (2) operating a process demonstration unit at the rate of 1 lb/hr recovered bitumen while producing clean sand and recyclable solvents; and (3) determine the economic conditions which will make a bitumen recovery project economical. DPR has analyzed the historical trends of domestic production, consumption, discoveries and reserves of crude oil. They have started an investigation of the volatility in the price of crude oil and of gasoline prices and of the differential between gasoline and crude oil. DPR continues to analyze the geographical movement and demand for asphalt products. Utah does not appear economically attractive as a site for a bitumen from tar sands asphalt plant. Oklahoma sites are now being studied. This report also contains the quarterly progress report from a University of Nevada study to determine bitumen composition, oxygen uptake rates, and viscosities of Alabama and Utah bitumens. Both reports have been indexed separately for inclusion on the data base.

  14. Solvent Retention Capacities of Oat Flour

    Directory of Open Access Journals (Sweden)

    Qianwen Niu

    2017-03-01

    Full Text Available This study measured the solvent retention capacities (SRCs of flours from eight oat varieties and one wheat variety against different solvents to explore the swelling volume of oat flour with different solvents, and thus provide a theoretical basis for quick β-glucan analysis. The SRC profile consists of water SRC (WSRC, 50% sucrose SRC (SSRC, 5% lactic acid SRC (LASRC, 5% Na2CO3 SRC (SCASRC, NaCl SRC (SCSRC, CaCl2 SRC (CCSRC, FeCl3 SRC (FCSRC, sodium cholate SRC (SCHSRC, NaOH (pH 10 SRC (SHSRC, Na2CO3 (pH 10 SRC (SCABSRC and SDS (pH 10 SRC (SDSSRC values, and a Chopin SRC kit was used to measure the SRC value. SRCs of the oat flours increased when the solvents turned from neutral (water and NaCl to acidic (5% lactic acid or alkaline (5% Na2CO3, CaCl2, FeCl3, NaOH and pH 10 Na2CO3, and rose as the metal ion valencies of the metal salts (NaCl, CaCl2 and FeCl3 increased. The β-glucan contents were significantly positively correlated with the SCSRC (0.83**, CCSRC (0.82**, SCHSRC (0.80** and FCSRC (0.78*. SRC measurements of β-glucan in oat flours revealed that the CCSRC values were related with β-glucan (0.64* but not related with protein and starch. CaCl2 could therefore potentially be exploited as a reagent for β-glucan assay.

  15. ACETANILIDA: SÍNTESE VERDE SEM SOLVENTE

    Directory of Open Access Journals (Sweden)

    Silvio Cunha

    2015-07-01

    Full Text Available We described herein a solvent-free synthesis of acetanilide developed in the context of green chemistry. The synthetic approach consisted of the reaction of aniline with acetic anhydride without additives, while using smaller amounts of reagents and water than previously described for this undergraduate experiment. The E Factor was 0.6 by experienced chemists and 0.9 by students.

  16. Critical reading and critical thinking Critical reading and critical thinking

    Directory of Open Access Journals (Sweden)

    Loni Kreis Taglieber

    2008-04-01

    Full Text Available The purpose of this paper is to provide, for L1 and L2 reading and writing teachers, a brief overview of the literature about critical reading and higher level thinking skills. The teaching of these skills is still neglected in some language classes in Brazil, be it in L1 or in L2 classes. Thus, this paper may also serve as a resource guide for L1 and/or L2 reading and writing teachers who want to incorporate critical reading and thinking into their classes. In modern society, even in everyday life people frequently need to deal with complicated public and political issues, make decisions, and solve problems. In order to do this efficiently and effectively, citizens must be able to evaluate critically what they see, hear, and read. Also, with the huge amount of printed material available in all areas in this age of “information explosion” it is easy to feel overwhelmed. But often the information piled up on people’s desks and in their minds is of no use due to the enormous amount of it. The purpose of this paper is to provide, for L1 and L2 reading and writing teachers, a brief overview of the literature about critical reading and higher level thinking skills. The teaching of these skills is still neglected in some language classes in Brazil, be it in L1 or in L2 classes. Thus, this paper may also serve as a resource guide for L1 and/or L2 reading and writing teachers who want to incorporate critical reading and thinking into their classes. In modern society, even in everyday life people frequently need to deal with complicated public and political issues, make decisions, and solve problems. In order to do this efficiently and effectively, citizens must be able to evaluate critically what they see, hear, and read. Also, with the huge amount of printed material available in all areas in this age of “information explosion” it is easy to feel overwhelmed. But often the information piled up on people’s desks and in their minds is of

  17. Percolation characteristics of solvent invasion in rough fractures under miscible conditions

    Science.gov (United States)

    Korfanta, M.; Babadagli, T.; Develi, K.

    2017-10-01

    Surface roughness and flow rate effects on the solvent transport under miscible conditions in a single fracture are studied. Surface replicas of seven different rocks (marble, granite, and limestone) are used to represent different surface roughness characteristics each described by different mathematical models including three fractal dimensions. Distribution of dyed solvent is investigated at various flow rate conditions to clarify the effect of roughness on convective and diffusive mixing. After a qualitative analysis using comparative images of different rocks, the area covered by solvent with respect to time is determined to conduct a semi-quantitative analysis. In this exercise, two distinct zones are identified, namely the straight lines obtained for convective (early times) and diffusive (late times) flow. The bending point between these two lines is used to point the transition between the two zones. Finally, the slopes of the straight lines and the bending points are correlated to five different roughness parameters and the rate (Peclet number). It is observed that both surface roughness and flow rate have significant effect on solvent spatial distribution. The largest area covered is obtained at moderate flow rates and hence not only the average surface roughness characteristic is important, but coessentially total fracture surface area needs to be considered when evaluating fluid distribution. It is also noted that the rate effect is critically different for the fracture samples of large grain size (marbles and granite) compared to smaller grain sizes (limestones). Variogram fractal dimension exhibits the strongest correlation with the maximum area covered by solvent, and display increasing trend at the moderate flow rates. Equations with variogram surface fractal dimension in combination with any other surface fractal parameter coupled with Peclet number can be used to predict maximum area covered by solvent in a single fracture, which in turn can be

  18. Solvent-assisted polymer micro-molding

    Institute of Scientific and Technical Information of China (English)

    HAN LuLu; ZHOU Jing; GONG Xiao; GAO ChangYou

    2009-01-01

    The micro-molding technology has played an important role in fabrication of polymer micro-patterns and development of functional devices.In such a process,suitable solvent can swell or dissolve the polymer films to decrease their glass transition temperature (Tg) and viscosity and thereby improve flowing ability.Consequently,it is easy to obtain the 2D and 3D patterns with high fidelity by the solvent-assisted micro-molding.Compared with the high temperature molding,this technology overcomes some shortcomings such as shrinking after cooling,degradation at high temperature,difficulty in processing some functional materials having high Tg,etc.It can be applied to making patterns not only on polymer monolayers but also on polyelectrolyte multilayers.Moreover,the compressioninduced patterns on the multilayers are chemically homogenous but physically heterogeneous.In this review,the controlling factors on the pattern quality are also discussed,including materials of the mold,solvent,pressure,temperature and pattern density.

  19. Dynamics of solvent-free grafted nanoparticles

    KAUST Repository

    Chremos, Alexandros

    2012-01-01

    The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space. © 2012 American Institute of Physics.

  20. Molecular accessibility in solvent swelled coals

    Energy Technology Data Exchange (ETDEWEB)

    Kispert, L.D.

    1993-02-01

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a non swelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration is measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method had also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data show that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 mn). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of the EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of coal, thus providing information on the importance of molecular shape.

  1. Criticality accident:

    International Nuclear Information System (INIS)

    Canavese, Susana I.

    2000-01-01

    A criticality accident occurred at 10:35 on September 30, 1999. It occurred in a precipitation tank in a Conversion Test Building at the JCO Tokai Works site in Tokaimura (Tokai Village) in the Ibaraki Prefecture of Japan. STA provisionally rated this accident a 4 on the seven-level, logarithmic International Nuclear Event Scale (INES). The September 30, 1999 criticality accident at the JCO Tokai Works Site in Tokaimura, Japan in described in preliminary, technical detail. Information is based on preliminary presentations to technical groups by Japanese scientists and spokespersons, translations by technical and non-technical persons of technical web postings by various nuclear authorities, and English-language non-technical reports from various news media and nuclear-interest groups. (author)

  2. Critical dynamics

    International Nuclear Information System (INIS)

    Dekker, H.

    1980-01-01

    It is shown how to solve the master equation for a Markov process including a critical point by means of successive approximations in terms of a small parameter. A critical point occurs if, by adjusting an externally controlled quantity, the system shows a transition from normal monostable to bistable behaviour. The fundamental idea of the theory is to separate the master equation into its proper irreducible part and a corrective remainder. The irreducible or zeroth order stochastic approximation will be a relatively simple Fokker-Planck equation that contains the essential features of the process. Once the solution of this irreducible equation is known, the higher order corrections in the original master equation can be incorporated in a systematic manner. (Auth.)

  3. Critical scattering

    International Nuclear Information System (INIS)

    Stirling, W.G.; Perry, S.C.

    1996-01-01

    We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO 3 is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs

  4. Molecular modeling study of agglomeration of [6,6]-phenyl-C61-butyric acid methyl ester in solvents.

    Science.gov (United States)

    Mortuza, S M; Banerjee, Soumik

    2012-12-28

    The molecular interactions between solvent and nanoparticles during photoactive layer formation in organic photovoltaic (OPV) cells influence the morphology of the photoactive layer and hence determine the power conversion efficiency. Prediction of optimal synthesis parameters in OPVs, such as choice of solvent, processing temperature, and nanoparticle concentration, requires fundamental understanding of the mechanisms that govern the agglomeration of nanoparticles in solvents. In this study, we used molecular dynamics simulations to simulate a commonly used organic nanoparticle, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), in various solvents to correlate solvent-nanoparticle interactions with the size of the agglomerate structure of PCBM. We analyzed the effects of concentration of PCBM and operating temperature on the molecular rearrangement and agglomeration of PCBM in three solvents: (i) toluene, (ii) indane, and (iii) toluene-indane mixture. We evaluated the agglomeration behavior of PCBM by determining sizes of the largest clusters of PCBM and the corresponding size distributions. To obtain further insight into the agglomerate structure of PCBMs, we evaluated radial distribution functions (RDFs) and coordination numbers of the various moieties of PCBMs with respect to solvent atoms as well as with respect to that of other PCBMs. Our simulations demonstrate that PCBMs form larger clusters in toluene while they are relatively dispersed in indane, which indicates the greater solubility of PCBM in indane than in toluene. In toluene-indane mixture, PCBMs are clustered to a greater extent than in indane and less than that in toluene. To correlate agglomerate size to nanoparticle-solvent interactions, we also evaluated the potential of mean force (PMF) of the fullerene moiety of PCBM in toluene and indane. Our results also show that the cluster size of PCBM molecules increases with the increase of concentration of PCBM and the processing temperature. To

  5. 40 CFR Table 3 to Subpart Pppp of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for... Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the... solvent blend matches both the name and CAS number for an entry, that entry's organic HAP mass fraction...

  6. 40 CFR Table 3 to Subpart Mmmm of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for... Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction.... If a solvent blend matches both the name and CAS number for an entry, that entry's organic HAP mass...

  7. Diluent effects in solvent extraction. The Effects of Diluents in Solvent Extraction - a literature study

    International Nuclear Information System (INIS)

    Loefstroem-Engdahl, Elin; Aneheim, Emma; Ekberg, Christian; Foreman, Mark; Skarnemark, Gunnar

    2010-01-01

    The fact that the choice of organic diluent is important for a solvent extraction process goes without saying. Several factors, such as e.g. price, flash point, viscosity, polarity etc. each have their place in the planning of a solvent extraction system. This high number of variables makes the lack of compilations concerning diluent effects to an interesting topic. Often the interest for the research concerning a specific extraction system focuses on the extractant used and the complexes built up during an extraction. The diluents used are often classical ones, even if it has been shown that choice of diluent can affect extraction as well as separation in an extraction system. An attempt to point out important steps in the understanding of diluent effects in solvent extraction is here presented. This large field is, of course, not summarized in this article, but an attempt is made to present important steps in the understanding of diluents effects in solvent extraction. Trying to make the information concerning diluent effects and applications more easily accessible this review offers a selected summarizing of literature concerning diluents effects in solvent extraction. (authors)

  8. Porous fiber formation in polymer-solvent system undergoing solvent evaporation

    Science.gov (United States)

    Dayal, Pratyush; Kyu, Thein

    2006-08-01

    Temporal evolution of the fiber morphology during dry spinning has been investigated in the framework of Cahn-Hilliard equation [J. Chem. Phys. 28, 258 (1958)] pertaining to the concentration order parameter or volume fraction given by the Flory-Huggins free energy of mixing [P. J. Flory, Principles of Polymer Chemistry (Cornell University Press, Ithaca, NY, 1953), p. 672] in conjunction with the solvent evaporation rate. To guide the solvent evaporation induced phase separation, equilibrium phase diagram of the starting polymer solution was established on the basis of the Flory-Huggins free energy of mixing. The quasi-steady-state approximation has been adopted to account for the nonconserved nature of the concentration field caused by the solvent loss. The process of solvent evaporation across the fiber skin-air interface was treated in accordance with the classical Fick's law [R. B. Bird et al., Transport Phenomena (J. Wiley, New York, 1960), p. 780]. The simulated morphologies include gradient type, hollow fiber type, bicontinuous type, and host-guest type. The development of these diverse fiber morphologies is explicable in terms of the phase diagram of the polymer solution in a manner dependent on the competition between the phase separation dynamics and rate of solvent evaporation.

  9. Gas chromatographic analysis of extractive solvent in reprocessing plants

    International Nuclear Information System (INIS)

    Marlet, B.

    1984-01-01

    Operation of a reprocessing plant using the Purex process is recalled and analytical controls for optimum performance are specified. The aim of this thesis is the development of analytical methods using gas chromatography required to follow the evolution of the extraction solvent during spent fuel reprocessing. The solvent at different concentrations, is analysed along the reprocessing lines in organic or aqueous phases. Solvent degradation interferes with extraction and decomposition products are analysed. The solvent becomes less and less efficient, also it is distilled and quality is checked. Traces of solvent should also be checked in waste water. Analysis are made as simple as possible to facilitate handling of radioactive samples [fr

  10. Batch extracting process using magnetic particle held solvents

    Science.gov (United States)

    Nunez, L.; Vandergrift, G.F.

    1995-11-21

    A process is described for selectively removing metal values which may include catalytic values from a mixture containing same, wherein a magnetic particle is contacted with a liquid solvent which selectively dissolves the metal values to absorb the liquid solvent onto the magnetic particle. Thereafter the solvent-containing magnetic particles are contacted with a mixture containing the heavy metal values to transfer metal values into the solvent carried by the magnetic particles, and then magnetically separating the magnetic particles. Ion exchange resins may be used for selective solvents. 5 figs.

  11. Actualización de los límites críticos del intervalo hídrico óptimo Review of the critical limits of the optimal hydric interval

    Directory of Open Access Journals (Sweden)

    Miguel Angel PIlatti

    2012-07-01

    Full Text Available El Intervalo Hídrico Óptimo (IHO es la fracción de agua edáfica fácilmente utilizable por los cultivos, durante la cual el suelo puede ser penetrado por las raíces sin mayor resistencia y la aeración no limita la respiración radical. En este trabajo se discuten los límites superior e inferior del IHO. El primero es èCC -agua retenida en capacidad de campo- si garantiza una aceptable capacidad de aire (èa; de lo contrario, el límite se alcanza cuando èa no restringe la respiración radical. El límite inferior queda determinado por la variable de mayor valor entre èRP (contenido hídrico edáfico por debajo del cual las raíces restringen su crecimiento, y èFU (agua fácilmente utilizable por debajo del cual comienza el estrés hídrico. Se analiza y discute la validez de los límites, y las dificultades metodológicas que implican sus determinaciones. Se comparan valores del IHO obtenidos por otros autores, que utilizaron diferentes límites, con los calculados con los límites críticos aquí propuestos. Cada situación agronómica (combinación de suelos, clima, cultivo requiere valores particulares de IHO que deberán ser determinados para cada región. Para el norte de la Región Pampeana (Argentina y sus cultivos habituales proponemos los siguientes valores críticos: èCC = contenido hídrico a -10 kPa; èa = 15%; èRP = 2,5 a 6 MPa (según el porcentaje de arcilla y èFU = -0,17 MPa.The Optimal Hydric Interval (IHO is the interval of easily available soil water for the crops, during which soil resistance and aeration do not limit root growth. In this paper, the upper and lower limits of the IHO are discussed. The upper limit is èCC (soil water content at field capacity when air capacity (èa is not restrictive for root respiration; otherwise, the limit is èa. The lower limit is determined by the variable of greater value between èRP (soil water content at which soil resistance reduces root elongation and èFU (soil water

  12. Deep Eutectic Solvents as Efficient Media for the Extraction and Recovery of Cynaropicrin from Cynara cardunculus L. Leaves.

    Science.gov (United States)

    de Faria, Emanuelle L P; do Carmo, Rafael S; Cláudio, Ana Filipa M; Freire, Carmen S R; Freire, Mara G; Silvestre, Armando J D

    2017-10-30

    In recent years a high demand for natural ingredients with nutraceutical properties has been witnessed, for which the development of more environmentally-friendly and cost-efficient extraction solvents and methods play a primary role. In this perspective, in this work, the application of deep eutectic solvents (DES), composed of quaternary ammonium salts and organic acids, as alternative solvents for the extraction of cynaropicrin from Cynara cardunculus L. leaves was studied. After selecting the most promising DES, their aqueous solutions were investigated, allowing to obtain a maximum cynaropicrin extraction yield of 6.20 wt %, using 70 wt % of water. The sustainability of the extraction process was further optimized by carrying out several extraction cycles, reusing either the biomass or the aqueous solutions of DES. A maximum cynaropicrin extraction yield of 7.76 wt % by reusing the solvent, and of 8.96 wt % by reusing the biomass, have been obtained. Taking advantage of the cynaropicrin solubility limit in aqueous solutions, water was added as an anti-solvent, allowing to recover 73.6 wt % of the extracted cynaropicrin. This work demonstrates the potential of aqueous solutions of DES for the extraction of value-added compounds from biomass and the possible recovery of both the target compounds and solvents.

  13. Switchable polarity solvent for liquid phase microextraction of Cd(II) as pyrrolidinedithiocarbamate chelates from environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, Erkan, E-mail: kimyager_erkan@hotmail.com; Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr

    2015-07-30

    A switchable polarity solvent was synthesized from triethylamine (TEA)/water/CO{sub 2} (Dry ice) via proton transfer reaction has been used for the microextraction of cadmium(II) as pyrrolidinedithiocarbamate (APDC) chelate. Cd(II)-APDC chelate was extracted into the switchable polarity solvent drops by adding 2 mL 10 M sodium hydroxide solution. Analytical parameters affecting the complex formation and microextraction efficiency such as pH, amount of ligand, volume of switchable polarity solvent and NaOH, sample volume were optimized. The effects of foreign ions were found tolerably. Under optimum conditions, the detection limit was 0.16 μg L{sup −1} (3Sb/m, n = 7) and the relative standard deviation was 5.4% (n = 7). The method was validated by the analysis of certified reference materials (TMDA-51.3 fortified water, TMDA-53.3 fortified water and SPS-WW2 waste water, 1573a Tomato Leaves and Oriental Basma Tobacco Leaves (INCT-OBTL-5)) and addition/recovery tests. The method was successfully applied to determination of cadmium contents of water, vegetable, fruit and cigarette samples. - Highlights: • Switchable polarity solvent was synthesized from triethylamine (TEA)/water/CO{sub 2}. • The switchable polarity solvent has been used for the microextraction of cadmium(II). • The important factors were optimized. • The method was applied to determination of cadmium in real samples.

  14. A NEW QUATERNARY MOBILE PHASE SYSTEM FOR OPTIMIZATION OF TLC SEPARATIONS OF ALKALOIDS USING MIXTURE DESIGNS AND RESPONSE-SURFACE MODELING

    NARCIS (Netherlands)

    COENEGRACHT, PMJ; DIJKMAN, M; DUINEVELD, CAA; METTING, HJ; ELEMA, ET; MALINGRE, TM

    1991-01-01

    A new combination of four organic solvents is proposed for the optimization of TLC separations of basic drugs and alkaloids. The solvents are diethylamine (DEA), methanol (MeOH), chloroform (CHCl3) and ethylacetate (EtAc). They were selected from a collection of ten solvents used in Normal Phase TLC

  15. Nonhazardous solvent composition and method for cleaning metal surfaces

    International Nuclear Information System (INIS)

    Googin, J.M.; Simandl, R.F.; Thompson, L.M.

    1993-01-01

    A solvent composition for displacing greasy and oily contaminants as well as water and/or aqueous residue from metallic surfaces, especially surfaces of radioactive materials so that such surfaces can be wiped clean of the displaced contaminants, water and/or aqueous residue. The solvent composition consists essentially of a blend of nonpolar aliphatic hydrocarbon solvent having a minimum flash point of about 140 F and 2 to 25 volume percent of a polar solvent having a flash point sufficiently high so as to provide the solvent composition with a minimum flash point of at least 140 F. The solvent composition is nonhazardous so that when it is used to clean the surfaces of radioactive materials the waste in the form of paper or cloth wipes, lab coats and the like used in the cleaning operation is not considered to be mixed waste composed of a hazardous solvent and a radioactive material

  16. Permeability of commercial solvents through living human skin

    DEFF Research Database (Denmark)

    Ursin, C; Hansen, C M; Van Dyk, J W

    1995-01-01

    A procedure has been developed for measuring the steady state rate of permeation of commercial solvents through living human skin. To get the most consistent results, it was necessary with some solvents to normalize the solvent permeation rate of a given skin sample with its [3H]water permeation...... rate. For other solvents this was not necessary, so the un-normalized data were used. High [3H]water permeation rate also was used as a criterion for "defective" skin samples that gave erroneous permeability rates, especially for solvents having slow permeability. The linearity of the steady state data...... of DMSO and octyl acetate were measured. No octyl acetate was detected and the permeability of DMSO was proportional to its mole fraction in the mixture. The effect of two hours of solvent exposure on the viability of skin (based on DNA synthesis) was measured and found to be very dependent on the solvent....

  17. Performance of thermal solvent process in Athabasca reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Das, Swapan [Marathon Oil (Canada)

    2011-07-01

    In the petroleum industry, due to depletion of conventional resources and high demand operators are looking into heavy oil and bitumen production. Different recovery methods exist, some of them based on heating the reservoir and others on the use of solvent. Thermal solvent process is a combination of both: a small amount of heat is used to maintain a solvent vapor phase in the reservoir. This process has advantages, solvent is mostly recycled which increases bitumen recovery efficiency and reduces the need for fresh solvent, but it also poses challenges, such as maintaining a vapor chamber and the fact that solvent solubility might be affected by heating. The aim of this paper is to discuss these issues. Simulations and field tests were conducted on bitumen in the the Athabasca region. This paper presented a thermal solvent process and its application's results in Athabasca reservoir.

  18. Solvent-free microwave extraction of essential oil from Melaleuca leucadendra L.

    Directory of Open Access Journals (Sweden)

    Widya Ismanto Aviarina

    2018-01-01

    Full Text Available Cajuput (Melaleuca leucadendra L. oil is one of potential commodity that provides an important role for the country’s foreign exchange but the extraction of these essential oil is still using conventional method such as hydrodistillation which takes a long time to produce essential oil with good quality. Therefore it is necessary to optimize the extraction process using a more effective and efficient method. So in this study the extraction is done using solvent-free microwave extraction method that are considered more effective and efficient than conventional methods. The optimum yield in the extraction of cajuput oil using solvent-free microwave extraction method is 1.0674%. The optimum yield is obtained on the feed to distiller (F/D ratio of 0.12 g/mL with microwave power of 400 W. In the extraction of cajuput oil using solvent-free microwave extraction method is performed first-order and second-order kinetics modelling. Based on kinetics modelling that has been done, it can be said that the second-order kinetic model (R2 = 0.9901 can be better represent experimental results of extraction of cajuput oil that using solvent-free microwave extraction method when compared with the first-order kinetic model (R2 = 0.9854.

  19. Collapse in two good solvents, swelling in two poor solvents: defying the laws of polymer solubility?

    Science.gov (United States)

    Mukherji, Debashish; Marques, Carlos M; Kremer, Kurt

    2018-01-17

    In this work we discuss two mirror but distinct phenomena of polymer paradoxical properties in mixed solvents: co-non-solvency and co-solvency. When a polymer collapses in a mixture of two miscible good solvents the phenomenon is known as co-non-solvency, while co-solvency is a phenomenon that is associated with the swelling of a polymer in poor solvent mixtures. A typical example of co-non-solvency is provided by poly(N-isopropylacrylamide) in aqueous alcohol, while poly(methyl methacrylate) in aqueous alcohol shows co-solvency. We discuss these two phenomena to compare their microscopic origins and show that both can be understood within generic universal concepts. A broad range of polymers is therefore expected to exhibit these phenomena where specific chemical details play a lesser role than the appropriate combination of interactions between the trio of molecular components.

  20. Single Stage Contactor Testing Of The Next Generation Solvent Blend

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.

    2014-01-06

    The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.

  1. Critical Mass

    CERN Multimedia

    AUTHOR|(CDS)2070299

    2017-01-01

    Critical Mass is a cycling event typically held on the last Friday of every month; its purpose is not usually formalized beyond the direct action of meeting at a set location and time and traveling as a group through city or town streets on bikes. The event originated in 1992 in San Francisco; by the end of 2003, the event was being held in over 300 cities around the world. At CERN it is held once a year in conjunction with the national Swiss campaing "Bike to work".

  2. Dynamic behaviour of solvent contactors in fuel reprocessing plants- an analysis

    Energy Technology Data Exchange (ETDEWEB)

    Raju, R P; Siddiqui, H R [Nuclear Waste Management Group, Bhabha Atomic Research Centre, Mumbai (India); Murthy, K K; Kansra, V P [Fuel Reprocessing Group, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    Fuel reprocessing plants carry out separation of useful fissile and fertile materials from spent nuclear fuels by isolating highly radioactive fission products using solvent extraction method. In the fuel reprocessing step of nuclear fuel cycle, optimisation of process parameters in the PUREX flowsheet design is of great importance particularly on account of the need to realize high degree of recovery of fissile and fertile materials and to ensure proper control on concentrations of fissile element in process streams for avoidance of criticality. In counter-current solvent contactors of PUREX flowsheet there are a variety of processes conditions which may cause plutonium accumulations that requires attention to ascertain safe Pu concentrations within the contactors. A study was carried out using the PUREX process mathematical model Solvent Extraction Program Having Interacting Solutes (SEPHIS) for pulsed solvent contactors in PREFRE-1, Tarapur and PREFRE-2, Kalpakkam flowsheets for optimising the process parameters in plutonium purification cycles. The study was extended to predict the behaviour of contactors handling plutonium bearing solutions under certain anticipated deviations in the process parameters. Modifications wherever necessary were carried out to the original SEPHIS code. This paper discusses the results obtained during this analysis. (author). 2 figs., 2 tabs.

  3. Friction of N-bead macromolecules in solution: Effects of the bead-solvent interaction

    International Nuclear Information System (INIS)

    Uvarov, Alexander; Fritzsche, Stephan

    2006-01-01

    The role of the bead-solvent interaction has been studied for its influence on the dynamics of an N-bead macromolecule which is immersed into a solution. Using a Fokker-Planck equation for the phase-space distribution function of the macromolecule, we show that all the effects of the solution can be treated entirely in terms of the friction tensors which are assigned to each pair of interacting beads in the chain. For the high-density as well as for the critical solvent, the properties of these tensors are discussed in detail and are calculated by using several (realistic) choices of the bead-solvent potential. From the friction tensors, moreover, an expression for the center-of-mass friction coefficient of a (N-bead) chain macromolecule is derived. Numerical data for this coefficient for 'truncated' Lennard-Jones bead-solvent potential are compared with results from molecular dynamic simulations and from the phenomenological theoretical data as found in the literature

  4. Anti-Solvent Crystallization Strategies for Highly Efficient Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Maria Konstantakou

    2017-09-01

    Full Text Available Solution-processed organic-inorganic halide perovskites are currently established as the hottest area of interest in the world of photovoltaics, ensuring low manufacturing cost and high conversion efficiencies. Even though various fabrication/deposition approaches and device architectures have been tested, researchers quickly realized that the key for the excellent solar cell operation was the quality of the crystallization of the perovskite film, employed to assure efficient photogeneration of carriers, charge separation and transport of the separated carriers at the contacts. One of the most typical methods in chemistry to crystallize a material is anti-solvent precipitation. Indeed, this classical precipitation method worked really well for the growth of single crystals of perovskite. Fortunately, the method was also effective for the preparation of perovskite films by adopting an anti-solvent dripping technique during spin-coating the perovskite precursor solution on the substrate. With this, polycrystalline perovskite films with pure and stable crystal phases accompanied with excellent surface coverage were prepared, leading to highly reproducible efficiencies close to 22%. In this review, we discuss recent results on highly efficient solar cells, obtained by the anti-solvent dripping method, always in the presence of Lewis base adducts of lead(II iodide. We present all the anti-solvents that can be used and what is the impact of them on device efficiencies. Finally, we analyze the critical challenges that currently limit the efficacy/reproducibility of this crystallization method and propose prospects for future directions.

  5. Changing the Mechanism for CO 2 Hydrogenation Using Solvent-Dependent Thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, Samantha A. [Catalysis Science Group, Pacific Northwest National Laboratory, P.O. Box 999 Richland WA 99352 USA; Appel, Aaron M. [Catalysis Science Group, Pacific Northwest National Laboratory, P.O. Box 999 Richland WA 99352 USA; Linehan, John C. [Catalysis Science Group, Pacific Northwest National Laboratory, P.O. Box 999 Richland WA 99352 USA; Wiedner, Eric S. [Catalysis Science Group, Pacific Northwest National Laboratory, P.O. Box 999 Richland WA 99352 USA

    2017-10-23

    A critical scientific challenge for utilization of CO2 is the development of catalyst systems that do not depend upon expensive or environmentally unfriendly reagents, such as precious metals, strong organic bases, and organic solvents. We have used thermodynamic insights to predict and demonstrate that the HCoI(dmpe)2 catalyst system, previously described for use in organic solvents, can hydrogenate CO2 to formate in water with bicarbonate as the only added reagent. Replacing tetrahydrofuran as the solvent with water changes the mechanism for catalysis by altering the thermodynamics for hydride transfer to CO2 from a key dihydride intermediate. The need for a strong organic base was eliminated by performing catalysis in water due to the change in mechanism. These studies demonstrate that the solvent plays a pivotal role in determining the reaction thermodynamics and thereby catalytic mechanism and activity. The research was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.

  6. Next Generation Solvent Development for Caustic-Side Solvent Extraction of Cesium

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Birdwell, Joseph F. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Bonnesen, Peter V. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2014-03-01

    This report summarizes the FY 2010 and 2011 accomplishments at Oak Ridge National Laboratory (ORNL) in developing the Next Generation Caustic-Side Solvent Extraction (NG-CSSX) process, referred to commonly as the Next Generation Solvent (NGS), under funding from the U.S. Department of Energy, Office of Environmental Management (DOE-EM), Office of Technology Innovation and Development. The primary product of this effort is a process solvent and preliminary flowsheet capable of meeting a target decontamination factor (DF) of 40,000 for worst-case Savannah River Site (SRS) waste with a concentration factor of 15 or higher in the 18-stage equipment configuration of the SRS Modular Caustic-Side Solvent Extraction Unit (MCU). In addition, the NG-CSSX process may be readily adapted for use in the SRS Salt Waste Processing Facility (SWPF) or in supplemental tank-waste treatment at Hanford upon appropriate solvent or flowsheet modifications. Efforts in FY 2010 focused on developing a solvent composition and process flowsheet for MCU implementation. In FY 2011 accomplishments at ORNL involved a wide array of chemical-development activities and testing up through single-stage hydraulic and mass-transfer tests in 5-cm centrifugal contactors. Under subcontract from ORNL, Argonne National Laboratory (ANL) designed a preliminary flowsheet using ORNL cesium distribution data, and Tennessee Technological University confirmed a chemical model for cesium distribution ratios (DCs) as a function of feed composition. Inter laboratory efforts were coordinated with complementary engineering tests carried out (and reported separately) by personnel at Savannah River National Laboratory (SRNL) and Savannah River Remediation (SRR) with helpful advice by Parsons Engineering and General Atomics on aspects of possible SWPF implementation.

  7. Next Generation Solvent (NGS): Development for Caustic-Side Solvent Extraction of Cesium

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Birdwell, Jr, Joseph F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bonnesen, Peter V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Delmau, Laetitia Helene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duncan, Nathan C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ensor, Dale [Tennessee Technological Univ., Cookeville, TN (United States); Hill, Talon G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Denise L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rajbanshi, Arbin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Roach, Benjamin D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Szczygiel, Patricia L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sloop, Jr., Frederick V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stoner, Erica L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Williams, Neil J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-03-01

    This report summarizes the FY 2010 and 2011 accomplishments at Oak Ridge National Laboratory (ORNL) in developing the Next Generation Caustic-Side Solvent Extraction (NG-CSSX) process, referred to commonly as the Next Generation Solvent (NGS), under funding from the U.S. Department of Energy, Office of Environmental Management (DOE-EM), Office of Technology Innovation and Development. The primary product of this effort is a process solvent and preliminary flowsheet capable of meeting a target decontamination factor (DF) of 40,000 for worst-case Savannah River Site (SRS) waste with a concentration factor of 15 or higher in the 18-stage equipment configuration of the SRS Modular Caustic-Side Solvent Extraction Unit (MCU). In addition, the NG-CSSX process may be readily adapted for use in the SRS Salt Waste Processing Facility (SWPF) or in supplemental tank-waste treatment at Hanford upon appropriate solvent or flowsheet modifications. Efforts in FY 2010 focused on developing a solvent composition and process flowsheet for MCU implementation. In FY 2011 accomplishments at ORNL involved a wide array of chemical-development activities and testing up through single-stage hydraulic and mass-transfer tests in 5-cm centrifugal contactors. Under subcontract from ORNL, Argonne National Laboratory (ANL) designed a preliminary flowsheet using ORNL cesium distribution data, and Tennessee Technological University confirmed a chemical model for cesium distribution ratios (DCs) as a function of feed composition. Interlaboratory efforts were coordinated with complementary engineering tests carried out (and reported separately) by personnel at Savannah River National Laboratory (SRNL) and Savannah River Remediation (SRR) with helpful advice by Parsons Engineering and General Atomics on aspects of possible SWPF implementation.

  8. Critical experiments facility and criticality safety programs at JAERI

    International Nuclear Information System (INIS)

    Kobayashi, Iwao; Tachimori, Shoichi; Takeshita, Isao; Suzaki, Takenori; Miyoshi, Yoshinori; Nomura, Yasushi

    1985-10-01

    The nuclear criticality safety is becoming a key point in Japan in the safety considerations for nuclear installations outside reactors such as spent fuel reprocessing facilities, plutonium fuel fabrication facilities, large scale hot alboratories, and so on. Especially a large scale spent fuel reprocessing facility is being designed and would be constructed in near future, therefore extensive experimental studies are needed for compilation of our own technical standards and also for verification of safety in a potential criticality accident to obtain public acceptance. Japan Atomic Energy Research Institute is proceeding a construction program of a new criticality safety experimental facility where criticality data can be obtained for such solution fuels as mainly handled in a reprocessing facility and also chemical process experiments can be performed to investigate abnormal phenomena, e.g. plutonium behavior in solvent extraction process by using pulsed colums. In FY 1985 detail design of the facility will be completed and licensing review by the government would start in FY 1986. Experiments would start in FY 1990. Research subjects and main specifications of the facility are described. (author)

  9. Compound forming extractants, solvating solvents and inert solvents IUPAC chemical data series

    CERN Document Server

    Marcus, Y; Kertes, A S

    2013-01-01

    Equilibrium Constants of Liquid-Liquid Distribution Reactions, Part III: Compound Forming Extractants, Solvating Solvents, and Inert Solvents focuses on the compilation of equilibrium constants of various compounds, such as acids, ions, salts, and aqueous solutions. The manuscript presents tables that show the distribution reactions of carboxylic and sulfonic acid extractants and their dimerization and other reactions in the organic phase and extraction reactions of metal ions from aqueous solutions. The book also states that the inorganic anions in these solutions are irrelevant, since they d

  10. Scenarios Evaluation Tool for Chlorinated Solvent MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, Karen; Michael J. Truex; Charles J. Newell; Brian Looney

    2007-02-28

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  11. On linear correlation between interfacial tension of water-solvent interface solubility of water in organic solvents and parameters of diluent effect scale

    International Nuclear Information System (INIS)

    Mezhov, Eh.A.; Khananashvili, N.L.; Shmidt, V.S.

    1988-01-01

    Presence of linear correlation between water solubility in nonmiscible with it organic solvents, interfacial tension of water-solvent interface, on the one hand, and solvent effect scale parameters and these solvents π* - on the other hand, is established. It allows, using certain tabular parameters of solvent effect or each solvent π*, to predict values of interfacial tension and water solubility for corresponding systems. It is shown, that solvent effect scale allows to predict values more accurately, than other known solvent scales, as it in contrast to other scales characterizes solvents, which are in equilibrium with water

  12. Solvent extraction of indium and gallium complexes with bromopyrogallol red by mixed extractants containing chloroform, a polar organic solvent and monocarboxylic acids

    International Nuclear Information System (INIS)

    Pyatnitskij, I.V.; Lysenko, O.V.; Kolomiets, L.L.

    1987-01-01

    Solvent extraction of indium and gallium complexes with bromopyragallol red (BPR) has been studied using mixed extractants containing chloroform, capronic acid (HL) and 1-pentanol (S) (extractant 1), and chloroform, HL, S and propionic acid (extractant 2). The latter is more selectie and extracts only the indium complex. Optimal conditions have been found for the extraction of In-BRP complex (pH 6.3-6.5; C BPR 1.5x10 -4 M) its composition has been estimated and discussed

  13. Anodic Oxidation of Furans in Aprotic Solvents.

    Science.gov (United States)

    1984-01-06

    dissolved in 70 mL acetonitrile (0.003% water , K.F. titration) containing 0.1 M tetra-n-butyl ammonium tetrafluoroborate (TBAF). The solution was...solvent evaporated on a rotary evaporator at 25°C ( water bath temperature). The residue was extracted with 3 x 20 mL portions of diethylether, and the...results for a clean electrode in the same solution after presaturation with oxygen. To make the film conductive for the electrolyses , the voltage was

  14. Solvent extraction studies on cadmium Part 3

    International Nuclear Information System (INIS)

    Alian, A.; El-Kot, A.

    1976-01-01

    An extraction study was performed on various concentrations of cadmium, zinc and cobalt halides in the presence of sulphuric acid. A long chain amine (Amberlite LA-2) and an organophosphorus solvent (TBP) were used. In most cases the value of the distribution ratio decreases with the increase of metal concentration in the aqueous phase. The various possibilities of chemical and radiochemical separations of cadmium from accompanying metal species are reported: separation of (sup109m)Ag from irradiated Cd targets, separation of (sup115m)In using HDEHP, separation of Cd and Zn from their mixtures. (T.G.)

  15. Comparison of microwave hydrodistillation and solvent-free microwave extraction of essential oil from Melaleuca leucadendra Linn

    Science.gov (United States)

    Ismanto, A. W.; Kusuma, H. S.; Mahfud, M.

    2017-12-01

    The comparison of solvent-free microwave extraction (SFME) and microwave hydrodistillation (MHD) in the extraction of essential oil from Melaleuca leucadendra Linn. was examined. Dry cajuput leaves were used in this study. The purpose of this study is also to determine optimal condition (microwave power). The relative electric consumption of SFME and MHD methods are both showing 0,1627 kWh/g and 0,3279 kWh/g. The results showed that solvent-free microwave extraction methods able to reduce energy consumption and can be regarded as a green technique for extraction of cajuput oil.

  16. Enhanced performance of dicationic ionic liquid electrolytes by organic solvents

    International Nuclear Information System (INIS)

    Li, Song; Feng, Guang; Cummings Peter, T; Zhang, Pengfei; Fulvio Pasquale, F; Hillesheim Patrick, C; Dai, Sheng

    2014-01-01

    The use of dicationic ionic liquid (DIL) electrolytes in supercapacitors is impeded by the slow dynamics of DILs, whereas the addition of organic solvents into DIL electrolytes improves ion transport and then enhances the power density of supercapacitors. In this work, the influences of organic solvents on the conductivity of DILs and the electrical double layer (EDL) of DIL-based supercapacitors are investigated using classical molecular dynamics simulation. Two types of organic solvents, acetonitrile (ACN) and propylene carbonate (PC), were used to explore the effects of different organic solvents on the EDL structure and capacitance of DIL/organic solvent-based supercapacitors. Firstly, it was found that the conductivity of DIL electrolytes was greatly enhanced in the presence of the organic solvent ACN. Secondly, a stronger adsorption of PC on graphite results in different EDL structures formed by DIL/ACN and DIL/PC electrolytes. The expulsion of co-ions from EDLs was observed in DIL/organic solvent electrolytes rather than neat DILs and this feature is more evident in DIL/PC. Furthermore, the bell-shaped differential capacitance–electric potential curve was not essentially changed by the presence of organic solvents. Comparing DIL/organic solvent electrolytes with neat DILs, the capacitance is slightly increased by organic solvents, which is in agreement with experimental observation. (paper)

  17. 19F NMR spectroscopy in monitoring fluorinated-solvent regeneration

    International Nuclear Information System (INIS)

    Ogorodnikov, V.D.; Bordunov, V.V.

    1987-01-01

    Extensive use is made of solvents such as trichloroethylene, freon-133, and perchloroethylene because they are good solvents for inorganic, plant, and animal greases, while the solvents can be recovered and there is no fire hazard. In this paper, the authors examined methods to monitor spent solution regeneration rapidly and with high accuracy. The authors tested perfluorinated telomeric alcohols as solvents for cleaning engineering components which have melting points of 60-120 degrees celsius. The higher working temperatures and the increased energy consumption are disadvantages of these solvents, but these are compensated for by the scope for using them virtually in the solid, liquid, and vapor states. The authors' proposed technology is based on solvents with melting points over 40 degrees celsius which produce virtually no wastes. The telomeric alcohols are recovered after cooling to normal conditions by separation from the oil by filtration and centrifugation, and they can be used in the next purification cycle. When the solvents have been regenerated, the petroleum products such as industrial oils can be reused for their original purpose. However, quantitative data are required on the solvent contents in the oil and the oil contents in the solvent in order to determine the degree of regeneration and the modes to be used. The authors have also proposed a quantitative method of determining traces of these alcohols in oils and residual oils in the solvent by fluorine NMR. All measurements were made with a BS497 NMR spectrometer

  18. Dictionary criticism

    DEFF Research Database (Denmark)

    Nielsen, Sandro

    2018-01-01

    Dictionary criticism is part of the lexicographical universe and reviewing of electronic and printed dictionaries is not an exercise in linguistics or in subject fields but an exercise in lexicography. It does not follow from this that dictionary reviews should not be based on a linguistic approach......, but that the linguistic approach is only one of several approaches to dictionary reviewing. Similarly, the linguistic and factual competences of reviewers should not be relegated to an insignificant position in the review process. Moreover, reviewers should define the object of their reviews, the dictionary, as a complex...... information tool with several components and in terms of significant lexicographical features: lexicographical functions, data and structures. This emphasises the fact that dictionaries are much more than mere vessels of linguistic categories, namely lexicographical tools that have been developed to fulfil...

  19. Solvents, Ethanol, Car Crashes and Tolerance: How Risky is Inhalation of Organic Solvents?

    Science.gov (United States)

    A research program in the National Health and Environmental Effects Research Laboratory of the U.S. EPA has led to some surprising considerations regarding the potential hazard of exposure to low concentrations of solvent vapors. This program involved conducting experiments to ch...

  20. PSE For Solvent Applications: A Generic Computer-aided Solvent Selection and Design Framework

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Sin, Gürkan; Gani, Rafiqul

    system engineering view that emphasizes a systematic and generic solution framework to solvent selection problems is presented. The framework integrates different methods and tools to manage the complexity and solve a wide range of problems in efficient and flexible manner. Its software implementation...