Final Rule: 2013 Conditional Exclusions From Solid Waste and Hazardous Waste for Solvent-Contaminated Wipes

EPA Pesticide Factsheets

This is a regulation page for the final rule EPA issued on July 31, 2013 that modifies the hazardous waste management regulations for solvent-contaminated wipes under the Resource Conservation and Recovery Act (RCRA).

Efficient implementation of three-dimensional reference interaction site model self-consistent-field method: Application to solvatochromic shift calculations

NASA Astrophysics Data System (ADS)

Minezawa, Noriyuki; Kato, Shigeki

2007-02-01

The authors present an implementation of the three-dimensional reference interaction site model self-consistent-field (3D-RISM-SCF) method. First, they introduce a robust and efficient algorithm for solving the 3D-RISM equation. The algorithm is a hybrid of the Newton-Raphson and Picard methods. The Jacobian matrix is analytically expressed in a computationally useful form. Second, they discuss the solute-solvent electrostatic interaction. For the solute to solvent route, the electrostatic potential (ESP) map on a 3D grid is constructed directly from the electron density. The charge fitting procedure is not required to determine the ESP. For the solvent to solute route, the ESP acting on the solute molecule is derived from the solvent charge distribution obtained by solving the 3D-RISM equation. Matrix elements of the solute-solvent interaction are evaluated by the direct numerical integration. A remarkable reduction in the computational time is observed in both routes. Finally, the authors implement the first derivatives of the free energy with respect to the solute nuclear coordinates. They apply the present method to "solute" water and formaldehyde in aqueous solvent using the simple point charge model, and the results are compared with those from other methods: the six-dimensional molecular Ornstein-Zernike SCF, the one-dimensional site-site RISM-SCF, and the polarizable continuum model. The authors also calculate the solvatochromic shifts of acetone, benzonitrile, and nitrobenzene using the present method and compare them with the experimental and other theoretical results.

Efficient implementation of three-dimensional reference interaction site model self-consistent-field method: application to solvatochromic shift calculations.

PubMed

Minezawa, Noriyuki; Kato, Shigeki

2007-02-07

The authors present an implementation of the three-dimensional reference interaction site model self-consistent-field (3D-RISM-SCF) method. First, they introduce a robust and efficient algorithm for solving the 3D-RISM equation. The algorithm is a hybrid of the Newton-Raphson and Picard methods. The Jacobian matrix is analytically expressed in a computationally useful form. Second, they discuss the solute-solvent electrostatic interaction. For the solute to solvent route, the electrostatic potential (ESP) map on a 3D grid is constructed directly from the electron density. The charge fitting procedure is not required to determine the ESP. For the solvent to solute route, the ESP acting on the solute molecule is derived from the solvent charge distribution obtained by solving the 3D-RISM equation. Matrix elements of the solute-solvent interaction are evaluated by the direct numerical integration. A remarkable reduction in the computational time is observed in both routes. Finally, the authors implement the first derivatives of the free energy with respect to the solute nuclear coordinates. They apply the present method to "solute" water and formaldehyde in aqueous solvent using the simple point charge model, and the results are compared with those from other methods: the six-dimensional molecular Ornstein-Zernike SCF, the one-dimensional site-site RISM-SCF, and the polarizable continuum model. The authors also calculate the solvatochromic shifts of acetone, benzonitrile, and nitrobenzene using the present method and compare them with the experimental and other theoretical results.

Solvent effects in time-dependent self-consistent field methods. I. Optical response calculations

DOE PAGES

Bjorgaard, J. A.; Kuzmenko, V.; Velizhanin, K. A.; ...

2015-01-22

In this study, we implement and examine three excited state solvent models in time-dependent self-consistent field methods using a consistent formalism which unambiguously shows their relationship. These are the linear response, state specific, and vertical excitation solvent models. Their effects on energies calculated with the equivalent of COSMO/CIS/AM1 are given for a set of test molecules with varying excited state charge transfer character. The resulting solvent effects are explained qualitatively using a dipole approximation. It is shown that the fundamental differences between these solvent models are reflected by the character of the calculated excitations.

SOLVENT-BASED TO WATERBASED ADHESIVE-COATED SUBSTRATE RETROFIT - VOLUME III: LABEL MANUFACTURING CASE STUDY: NASHUA CORPORATION

EPA Science Inventory

This volume discusses Nashua Corporation's Omaha facility, a label and label stock manufacturing facility that no longer uses solvent-based adhesives. Information obtained includes issues related to the technical, economic, and environmental barriers and opportunities associated ...

Emerging Trends in Regulatory Implementation of MNA

EPA Science Inventory

There are two EPA documents relevant to MNA of Chlorinated Solvents: the Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Ground Water. EPA/600/R-98/128 September, 1998, and Use of Monitored Natural Attenuation at Superfund, RCRA Corrective Action...

Experimental Limiting Oxygen Concentrations for Nine Organic Solvents at Temperatures and Pressures Relevant to Aerobic Oxidations in the Pharmaceutical Industry

PubMed Central

2015-01-01

Applications of aerobic oxidation methods in pharmaceutical manufacturing are limited in part because mixtures of oxygen gas and organic solvents often create the potential for a flammable atmosphere. To address this issue, limiting oxygen concentration (LOC) values, which define the minimum partial pressure of oxygen that supports a combustible mixture, have been measured for nine commonly used organic solvents at elevated temperatures and pressures. The solvents include acetic acid, N-methylpyrrolidone, dimethyl sulfoxide, tert-amyl alcohol, ethyl acetate, 2-methyltetrahydrofuran, methanol, acetonitrile, and toluene. The data obtained from these studies help define safe operating conditions for the use of oxygen with organic solvents. PMID:26622165

Application of a Solvent Emulsion Technology for PCB Removal from Older Structures on DoD Facilities

DTIC Science & Technology

2011-11-01

Solvent Emulsion Technology for PCB Removal from Older Structures on DoD Facilities November 2011 Report Documentation Page Form ApprovedOMB No. 0704...to 00-00-2011 4. TITLE AND SUBTITLE Application of a Solvent Emulsion Technology for PCB Removal from Older Structures on DoD Facilities 5a...EASE OF IMPLEMENTATION .......................................................................... 13  3.4  REDUCTION IN PCB CONCENTRATIONS IN TREATED

Protecting High Energy Barriers: A New Equation to Regulate Boost Energy in Accelerated Molecular Dynamics Simulations.

PubMed

Sinko, William; de Oliveira, César Augusto F; Pierce, Levi C T; McCammon, J Andrew

2012-01-10

Molecular dynamics (MD) is one of the most common tools in computational chemistry. Recently, our group has employed accelerated molecular dynamics (aMD) to improve the conformational sampling over conventional molecular dynamics techniques. In the original aMD implementation, sampling is greatly improved by raising energy wells below a predefined energy level. Recently, our group presented an alternative aMD implementation where simulations are accelerated by lowering energy barriers of the potential energy surface. When coupled with thermodynamic integration simulations, this implementation showed very promising results. However, when applied to large systems, such as proteins, the simulation tends to be biased to high energy regions of the potential landscape. The reason for this behavior lies in the boost equation used since the highest energy barriers are dramatically more affected than the lower ones. To address this issue, in this work, we present a new boost equation that prevents oversampling of unfavorable high energy conformational states. The new boost potential provides not only better recovery of statistics throughout the simulation but also enhanced sampling of statistically relevant regions in explicit solvent MD simulations.

SOLVENT-BASED TO WATERBASED ADHESIVE-COATED SUBSTRATE RETROFIT - VOLUME II: PROCESS OVERVIEW

EPA Science Inventory

This volume presents initial results of a study to identify the issues and barriers associated with retrofitting existing solvent-based equipment to accept waterbased adhesives as part of an EPA effort to improve equipment cleaning in the coated and laminated substrate manufactur...

Quality of Chemical Safety Information in Printing Industry.

PubMed

Tsai, Chung-Jung; Mao, I-Fang; Ting, Jo-Yu; Young, Chi-Hsien; Lin, Jhih-Sian; Li, Wei-Lun

2016-04-01

Employees in printing industries can be exposed to multiple solvents in their work environment. The objectives of this study were to investigate the critical components of chemical solvents by analyzing the components of the solvents and collecting the Safety data sheets (SDSs), and to evaluate the hazard communication implementation status in printing industries. About 152 printing-related industries were recruited by area-stratified random sampling and included 23 plate-making, 102 printing and 27 printing-assistance companies in Taiwan. We analyzed company questionnaires (n = 152), SDSs (n = 180), and solvents (n = 20) collected from this sample of printing-related companies. Analytical results indicated that benzene and ethylbenzene, which were carcinogen and possibly carcinogen, were detectable in the cleaning solvents, and the detection rate were 54.5% (concentrations: <0.011-0.035 wt%) and 63.6% (concentrations: <0.011-6.22 wt%), respectively; however, neither compound was disclosed in the SDS for the solvents. Several other undisclosed components, including methanol, isopropanol and n-butanol, were also identified in the printing inks, fountain solutions and dilution solvents. We noted that, of the companies we surveyed, only 57.2% had a hazard communication program, 61.8% had SDSs on file and 59.9% provided employee safety and health training. We note that hazard communication programs were missing or ineffective in almost half of the 152 printing industries surveyed. Current safety information of solvents components in printing industries was inadequate, and many hazardous compounds were undisclosed in the SDSs of the solvents or the labels of the containers. The implementation of hazard communications in printing industries was still not enough for protecting the employees' safety and health. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Quality of Chemical Safety Information in Printing Industry

PubMed Central

Tsai, Chung-Jung; Mao, I-Fang; Ting, Jo-Yu; Young, Chi-Hsien; Lin, Jhih-Sian; Li, Wei-Lun

2016-01-01

Objectives: Employees in printing industries can be exposed to multiple solvents in their work environment. The objectives of this study were to investigate the critical components of chemical solvents by analyzing the components of the solvents and collecting the Safety data sheets (SDSs), and to evaluate the hazard communication implementation status in printing industries. Method: About 152 printing-related industries were recruited by area-stratified random sampling and included 23 plate-making, 102 printing and 27 printing-assistance companies in Taiwan. We analyzed company questionnaires (n = 152), SDSs (n = 180), and solvents (n = 20) collected from this sample of printing-related companies. Results: Analytical results indicated that benzene and ethylbenzene, which were carcinogen and possibly carcinogen, were detectable in the cleaning solvents, and the detection rate were 54.5% (concentrations: <0.011–0.035 wt%) and 63.6% (concentrations: <0.011–6.22 wt%), respectively; however, neither compound was disclosed in the SDS for the solvents. Several other undisclosed components, including methanol, isopropanol and n-butanol, were also identified in the printing inks, fountain solutions and dilution solvents. We noted that, of the companies we surveyed, only 57.2% had a hazard communication program, 61.8% had SDSs on file and 59.9% provided employee safety and health training. We note that hazard communication programs were missing or ineffective in almost half of the 152 printing industries surveyed. Conclusions: Current safety information of solvents components in printing industries was inadequate, and many hazardous compounds were undisclosed in the SDSs of the solvents or the labels of the containers. The implementation of hazard communications in printing industries was still not enough for protecting the employees’ safety and health. PMID:26568584

MICROWAVE ACCELERATED SOLVENT-FREE CHEMICAL REACTIONS, PUBLISHED IN AMPERE NEWSLETTER, ISSUE 29, JUNE 2001

EPA Science Inventory

The worldwide annual usage of volatile organic solvents is generally of the order of ~4 billion pounds. In the environmentally conscieous era, the focus in to design chemical processes and products that eliminate or minimize the waste generation and the ideal approach may compris...

PARALLEL MULTIOBJECTIVE EVOLUTIONARY ALGORITHMS FOR WASTE SOLVENT RECYCLING

EPA Science Inventory

Waste solvents are of great concern to the chemical process industries and to the public, and many technologies have been suggested and implemented in the chemical process industries to reduce waste and associated environmental impacts. In this article we have developed a novel p...

40 CFR 469.13 - Monitoring.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of my knowledge and belief, no dumping of concentrated toxic organics into the wastewaters has... implementing the solvent management plan submitted to the permitting authority.” (b) In requesting that no monitoring of TTO be required, the direct discharger shall submit a solvent management plan that specifies to...

40 CFR 469.13 - Monitoring.

Code of Federal Regulations, 2014 CFR

2014-07-01

... of my knowledge and belief, no dumping of concentrated toxic organics into the wastewaters has... implementing the solvent management plan submitted to the permitting authority.” (b) In requesting that no monitoring of TTO be required, the direct discharger shall submit a solvent management plan that specifies to...

40 CFR 469.13 - Monitoring.

Code of Federal Regulations, 2013 CFR

2013-07-01

... of my knowledge and belief, no dumping of concentrated toxic organics into the wastewaters has... implementing the solvent management plan submitted to the permitting authority.” (b) In requesting that no monitoring of TTO be required, the direct discharger shall submit a solvent management plan that specifies to...

78 FR 5290 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Reasonably Available...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-25

...: Paper, film, and foil coatings; industrial cleaning solvents; miscellaneous metal and plastic parts... solvents; (3) miscellaneous metal and plastic parts coatings; (4) large appliance coatings; (5) offset... protection, Air pollution control, Incorporation by reference, Intergovernmental relations, Ozone, Reporting...

Nanofiltration-Enabled In Situ Solvent and Reagent Recycle for Sustainable Continuous-Flow Synthesis.

PubMed

Fodi, Tamas; Didaskalou, Christos; Kupai, Jozsef; Balogh, Gyorgy T; Huszthy, Peter; Szekely, Gyorgy

2017-09-11

Solvent usage in the pharmaceutical sector accounts for as much as 90 % of the overall mass during manufacturing processes. Consequently, solvent consumption poses significant costs and environmental burdens. Continuous processing, in particular continuous-flow reactors, have great potential for the sustainable production of pharmaceuticals but subsequent downstream processing remains challenging. Separation processes for concentrating and purifying chemicals can account for as much as 80 % of the total manufacturing costs. In this work, a nanofiltration unit was coupled to a continuous-flow rector for in situ solvent and reagent recycling. The nanofiltration unit is straightforward to implement and simple to control during continuous operation. The hybrid process operated continuously over six weeks, recycling about 90 % of the solvent and reagent. Consequently, the E-factor and the carbon footprint were reduced by 91 % and 19 %, respectively. Moreover, the nanofiltration unit led to a solution of the product eleven times more concentrated than the reaction mixture and increased the purity from 52.4 % to 91.5 %. The boundaries for process conditions were investigated to facilitate implementation of the methodology by the pharmaceutical sector. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental limiting oxygen concentrations for nine organic solvents at temperatures and pressures relevant to aerobic oxidations in the pharmaceutical industry

DOE PAGES

Osterberg, Paul M.; Niemeier, Jeffry K.; Welch, Christopher J.; ...

2014-12-06

Applications of aerobic oxidation methods in pharmaceutical manufacturing are limited in part because mixtures of oxygen gas and organic solvents often create the potential for a flammable atmosphere. To address this issue, limiting oxygen concentration (LOC) values, which define the minimum partial pressure of oxygen that supports a combustible mixture, have been measured for nine commonly used organic solvents at elevated temperatures and pressures. The solvents include acetic acid, N-methylpyrrolidone, dimethyl sulfoxide, tert-amyl alcohol, ethyl acetate, 2-methyltetrahydrofuran, methanol, acetonitrile, and toluene. Furthermore, the data obtained from these studies help define safe operating conditions for the use of oxygen with organicmore » solvents.« less

Numerical Treatment of Stokes Solvent Flow and Solute-Solvent Interfacial Dynamics for Nonpolar Molecules.

PubMed

Sun, Hui; Zhou, Shenggao; Moore, David K; Cheng, Li-Tien; Li, Bo

2016-05-01

We design and implement numerical methods for the incompressible Stokes solvent flow and solute-solvent interface motion for nonpolar molecules in aqueous solvent. The balance of viscous force, surface tension, and van der Waals type dispersive force leads to a traction boundary condition on the solute-solvent interface. To allow the change of solute volume, we design special numerical boundary conditions on the boundary of a computational domain through a consistency condition. We use a finite difference ghost fluid scheme to discretize the Stokes equation with such boundary conditions. The method is tested to have a second-order accuracy. We combine this ghost fluid method with the level-set method to simulate the motion of the solute-solvent interface that is governed by the solvent fluid velocity. Numerical examples show that our method can predict accurately the blow up time for a test example of curvature flow and reproduce the polymodal (e.g., dry and wet) states of hydration of some simple model molecular systems.

Numerical Treatment of Stokes Solvent Flow and Solute-Solvent Interfacial Dynamics for Nonpolar Molecules

PubMed Central

Sun, Hui; Zhou, Shenggao; Moore, David K.; Cheng, Li-Tien; Li, Bo

2015-01-01

We design and implement numerical methods for the incompressible Stokes solvent flow and solute-solvent interface motion for nonpolar molecules in aqueous solvent. The balance of viscous force, surface tension, and van der Waals type dispersive force leads to a traction boundary condition on the solute-solvent interface. To allow the change of solute volume, we design special numerical boundary conditions on the boundary of a computational domain through a consistency condition. We use a finite difference ghost fluid scheme to discretize the Stokes equation with such boundary conditions. The method is tested to have a second-order accuracy. We combine this ghost fluid method with the level-set method to simulate the motion of the solute-solvent interface that is governed by the solvent fluid velocity. Numerical examples show that our method can predict accurately the blow up time for a test example of curvature flow and reproduce the polymodal (e.g., dry and wet) states of hydration of some simple model molecular systems. PMID:27365866

Cleanliness verification process at Martin Marietta Astronautics

NASA Astrophysics Data System (ADS)

King, Elizabeth A.; Giordano, Thomas J.

1994-06-01

The Montreal Protocol and the 1990 Clean Air Act Amendments mandate CFC-113, other chlorinated fluorocarbons (CFC's) and 1,1,1-Trichloroethane (TCA) be banned from production after December 31, 1995. In response to increasing pressures, the Air Force has formulated policy that prohibits purchase of these solvents for Air Force use after April 1, 1994. In response to the Air Force policy, Martin Marietta Astronautics is in the process of eliminating all CFC's and TCA from use at the Engineering Propulsion Laboratory (EPL), located on Air Force property PJKS. Gross and precision cleaning operations are currently performed on spacecraft components at EPL. The final step of the operation is a rinse with a solvent, typically CFC-113. This solvent is then analyzed for nonvolatile residue (NVR), particle count and total filterable solids (TFS) to determine cleanliness of the parts. The CFC-113 used in this process must be replaced in response to the above policies. Martin Marietta Astronautics, under contract to the Air Force, is currently evaluating and testing alternatives for a cleanliness verification solvent. Completion of test is scheduled for May, 1994. Evaluation of the alternative solvents follows a three step approach. This first is initial testing of solvents picked from literature searches and analysis. The second step is detailed testing of the top candidates from the initial test phase. The final step is implementation and validation of the chosen alternative(s). Testing will include contaminant removal, nonvolatile residue, material compatibility and propellant compatibility. Typical materials and contaminants will be tested with a wide range of solvents. Final results of the three steps will be presented as well as the implementation plan for solvent replacement.

Next Generation Solvent (NGS): Development for Caustic-Side Solvent Extraction of Cesium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moyer, Bruce A.; Birdwell, Jr, Joseph F.; Bonnesen, Peter V.

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 Modularmore » 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.« less

Next Generation Solvent Development for Caustic-Side Solvent Extraction of Cesium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moyer, Bruce A.; Birdwell, Joseph F.; Bonnesen, Peter V.

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 Modularmore » 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.« less

Organic solvent pretreatment of lignocellulosic biomass for biofuels and biochemicals: A review.

PubMed

Zhang, Ke; Pei, Zhijian; Wang, Donghai

2016-01-01

Lignocellulosic biomass represents the largest potential volume and lowest cost for biofuel and biochemical production. Pretreatment is an essential component of biomass conversion process, affecting a majority of downstream processes, including enzymatic hydrolysis, fermentation, and final product separation. Organic solvent pretreatment is recognized as an emerging way ahead because of its inherent advantages, such as the ability to fractionate lignocellulosic biomass into cellulose, lignin, and hemicellulose components with high purity, as well as easy solvent recovery and solvent reuse. Objectives of this review were to update and extend previous works on pretreatment of lignocellulosic biomass for biofuels and biochemicals using organic solvents, especially on ethanol, methanol, ethylene glycol, glycerol, acetic acid, and formic acid. Perspectives and recommendations were given to fully describe implementation of proper organic solvent pretreatment for future research. Copyright © 2015 Elsevier Ltd. All rights reserved.

3DRISM-HI-D2MSA: an improved analytic theory to compute solvent structure around hydrophobic solutes with proper treatment of solute–solvent electrostatic interactions

NASA Astrophysics Data System (ADS)

Cao, Siqin; Zhu, Lizhe; Huang, Xuhui

2018-04-01

The 3D reference interaction site model (3DRISM) is a powerful tool to study the thermodynamic and structural properties of liquids. However, for hydrophobic solutes, the inhomogeneity of the solvent density around them poses a great challenge to the 3DRISM theory. To address this issue, we have previously introduced the hydrophobic-induced density inhomogeneity theory (HI) for purely hydrophobic solutes. To further consider the complex hydrophobic solutes containing partial charges, here we propose the D2MSA closure to incorporate the short-range and long-range interactions with the D2 closure and the mean spherical approximation, respectively. We demonstrate that our new theory can compute the solvent distributions around real hydrophobic solutes in water and complex organic solvents that agree well with the explicit solvent molecular dynamics simulations.

Assessing implicit models for nonpolar mean solvation forces: The importance of dispersion and volume terms

PubMed Central

Wagoner, Jason A.; Baker, Nathan A.

2006-01-01

Continuum solvation models provide appealing alternatives to explicit solvent methods because of their ability to reproduce solvation effects while alleviating the need for expensive sampling. Our previous work has demonstrated that Poisson-Boltzmann methods are capable of faithfully reproducing polar explicit solvent forces for dilute protein systems; however, the popular solvent-accessible surface area model was shown to be incapable of accurately describing nonpolar solvation forces at atomic-length scales. Therefore, alternate continuum methods are needed to reproduce nonpolar interactions at the atomic scale. In the present work, we address this issue by supplementing the solvent-accessible surface area model with additional volume and dispersion integral terms suggested by scaled particle models and Weeks–Chandler–Andersen theory, respectively. This more complete nonpolar implicit solvent model shows very good agreement with explicit solvent results and suggests that, although often overlooked, the inclusion of appropriate dispersion and volume terms are essential for an accurate implicit solvent description of atomic-scale nonpolar forces. PMID:16709675

Simulations of fluorescence solvatochromism in substituted PPV oligomers from excited state molecular dynamics with implicit solvent

DOE PAGES

Bjorgaard, J. A.; Nelson, T.; Kalinin, K.; ...

2015-04-28

In this study, an efficient method of treating solvent effects in excited state molecular dynamics (ESMD) is implemented and tested by exploring the solvatochromic effects in substituted p-phenylene vinylene oligomers. A continuum solvent model is used which has very little computational overhead. This allows simulations of ESMD with solvent effects on the scale of hundreds of picoseconds for systems of up to hundreds of atoms. At these time scales, solvatochromic shifts in fluoresence spectra can be described. Solvatochromic shifts in absorption and fluorescence spectra from ESMD are compared with time-dependent density functional theory calculations and experiments.

76 FR 70888 - Revisions to the California State Implementation Plan, South Coast Air Quality Management District

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-16

... volatile organic compound (VOC) emissions from paint thinners and multi-purpose solvents and from... waterborne chemistry, while coatings that required thinning with solvents accounted for only 0.28% of the... 2010 data indicates that 93.2% of the coatings sold were of waterborne chemistry.\\6\\ Therefore, the...

Comparison Pore Aggregate Levels After Extraction With Solvents Pertamax Plus And Gasoline

NASA Astrophysics Data System (ADS)

Anggraini, Muthia

2017-12-01

Loss of asphalt content extraction results become problems in Field Work For implementing parties. The use of solvents with high octane (pertamax plus) for the extraction, dissolving the asphalt more than gasoline. By comparing the levels of aggregate pores after using solvent extraction pertamax plus compared to gasoline could answer that pertamax plus more solvent dissolves the bitumen compared to gasoline. This study aims to obtain comparative levels of porous aggregate mix AC-WC after using solvent extraction pertamax plus compared to gasoline. This study uses the aggregate that has been extracted from the production of asphalt mixtures, when finisher and after compaction field. The method used is the assay of coarse and fine aggregate pores, extraction of bitumen content to separate the aggregate with bitumen. Results of testing the total absorption after extraction using a solvent preta max plus in the production of asphalt mixtures 0.80%, while gasoline solvent 0.67% deviation occurs 0.13%. In the finisher after the solvent extraction preta max plus 0.77%, while 0.67% gasoline solvent occurs deviation of 0.1%. At the core after extraction and solvent pertamax plus 0.71%, while gasoline solvent 0.60% 0.11% deviation occurs. The total water absorption after extraction using a solvent pertamax plus greater than gasoline. This proves that the solvent dissolves pertamax plus more asphalt than gasoline.

Further development of a robust workup process for solution-phase high-throughput library synthesis to address environmental and sample tracking issues.

PubMed

Kuroda, Noritaka; Hird, Nick; Cork, David G

2006-01-01

During further improvement of a high-throughput, solution-phase synthesis system, new workup tools and apparatus for parallel liquid-liquid extraction and evaporation have been developed. A combination of in-house design and collaboration with external manufacturers has been used to address (1) environmental issues concerning solvent emissions and (2) sample tracking errors arising from manual intervention. A parallel liquid-liquid extraction unit, containing miniature high-speed magnetic stirrers for efficient mixing of organic and aqueous phases, has been developed for use on a multichannel liquid handler. Separation of the phases is achieved by dispensing them into a newly patented filter tube containing a vertical hydrophobic porous membrane, which allows only the organic phase to pass into collection vials positioned below. The vertical positioning of the membrane overcomes the hitherto dependence on the use of heavier-than-water, bottom-phase, organic solvents such as dichloromethane, which are restricted due to environmental concerns. Both small (6-mL) and large (60-mL) filter tubes were developed for parallel phase separation in library and template synthesis, respectively. In addition, an apparatus for parallel solvent evaporation was developed to (1) remove solvent from the above samples with highly efficient recovery and (2) avoid the movement of individual samples between their collection on a liquid handler and registration to prevent sample identification errors. The apparatus uses a diaphragm pump to achieve a dynamic circulating closed system with a heating block for the rack of 96 sample vials and an efficient condenser to trap the solvents. Solvent recovery is typically >98%, and convenient operation and monitoring has made the apparatus the first choice for removal of volatile solvents.

75 FR 72963 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Control of Volatile...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-29

... Promulgation of Air Quality Implementation Plans; Maryland; Control of Volatile Organic Compound Emissions From Industrial Solvent Cleaning Operations; Withdrawal of Direct Final Rule AGENCY: Environmental Protection... withdrawing the direct final rule to approve revisions to Maryland's State Implementation Plan (SIP). This SIP...

Implementation of GPC characterization of asphalt binders at Louisiana materials laboratory.

DOT National Transportation Integrated Search

2013-10-01

This research implemented a procedure for using gel permeation chromatography (GPC) as an analytical tool to : define the percentage amounts of polymer modifiers, which are soluble in eluting GPC solvents, in polymermodified asphalt cements. It also ...

New Analytical Method for the Determination of Detergent Concentration in Water by Fabric Dyeing

ERIC Educational Resources Information Center

Seng, Set; Kita, Masakazu; Sugihara, Reiko

2007-01-01

The use of harmful organic solvents in classrooms has become a critical issue of concern in the field of chemistry education. This article describes a classroom activity at a high school in which an acrylic fabric was used as the extraction medium in the analysis of the detergent concentration in water instead of organic solvents. Dyes were used…

Solvent signal suppression for high-resolution MAS-DNP

NASA Astrophysics Data System (ADS)

Lee, Daniel; Chaudhari, Sachin R.; De Paëpe, Gaël

2017-05-01

Dynamic nuclear polarization (DNP) has become a powerful tool to substantially increase the sensitivity of high-field magic angle spinning (MAS) solid-state NMR experiments. The addition of dissolved hyperpolarizing agents usually results in the presence of solvent signals that can overlap and obscure those of interest from the analyte. Here, two methods are proposed to suppress DNP solvent signals: a Forced Echo Dephasing experiment (FEDex) and TRAnsfer of Populations in DOuble Resonance Echo Dephasing (TRAPDORED) NMR. These methods reintroduce a heteronuclear dipolar interaction that is specific to the solvent, thereby forcing a dephasing of recoupled solvent spins and leaving acquired NMR spectra free of associated resonance overlap with the analyte. The potency of these methods is demonstrated on sample types common to MAS-DNP experiments, namely a frozen solution (of L-proline) and a powdered solid (progesterone), both containing deuterated glycerol as a DNP solvent. The proposed methods are efficient, simple to implement, compatible with other NMR experiments, and extendable past spectral editing for just DNP solvents. The sensitivity gains from MAS-DNP in conjunction with FEDex or TRAPDORED then permits rapid and uninterrupted sample analysis.

Greener "Solutions" for the Organic Chemistry Teaching Lab: Exploring the Advantages of Alternative Reaction Media

ERIC Educational Resources Information Center

McKenzie, Lallie C.; Huffman, Lauren M.; Hutchison, James E.; Rogers, Courtney E.; Goodwin, Thomas E.; Spessard, Gary O.

2009-01-01

A major approach for implementing green chemistry is the discovery and development of synthetic strategies that reduce the quantity of solvent needed, eliminate it altogether, or rely on new reaction media. An increasing number of examples have demonstrated that greener reaction solvents or media can enhance performance as well as reduce hazard.…

A microfluidic study of liquid-liquid extraction mediated by carbon dioxide.

PubMed

Lestari, Gabriella; Salari, Alinaghi; Abolhasani, Milad; Kumacheva, Eugenia

2016-07-05

Liquid-liquid extraction is an important separation and purification method; however, it faces a challenge in reducing the energy consumption and the environmental impact of solvent (extractant) recovery. The reversible chemical reactions of switchable solvents (nitrogenous bases) with carbon dioxide (CO2) can be implemented in reactive liquid-liquid extraction to significantly reduce the cost and energy requirements of solvent recovery. The development of new effective switchable solvents reacting with CO2 and the optimization of extraction conditions rely on the ability to evaluate and screen the performance of switchable solvents in extraction processes. We report a microfluidic strategy for time- and labour-efficient studies of CO2-mediated solvent extraction. The platform utilizes a liquid segment containing an aqueous extractant droplet and a droplet of a solution of a switchable solvent in a non-polar liquid, with gaseous CO2 supplied to the segment from both sides. Following the reaction of the switchable solvent with CO2, the solvent becomes hydrophilic and transfers from the non-polar solvent to the aqueous droplet. By monitoring the time-dependent variation in droplet volumes, we determined the efficiency and extraction time for the CO2-mediated extraction of different nitrogenous bases in a broad experimental parameter space. The platform enables a significant reduction in the amount of switchable solvents used in these studies, provides accurate temporal characterization of the liquid-liquid extraction process, and offers the capability of high-throughput screening of switchable solvents.

Quantum Monte Carlo studies of solvated systems

NASA Astrophysics Data System (ADS)

Schwarz, Kathleen; Letchworth Weaver, Kendra; Arias, T. A.; Hennig, Richard G.

2011-03-01

Solvation qualitatively alters the energetics of diverse processes from protein folding to reactions on catalytic surfaces. An explicit description of the solvent in quantum-mechanical calculations requires both a large number of electrons and exploration of a large number of configurations in the phase space of the solvent. These problems can be circumvented by including the effects of solvent through a rigorous classical density-functional description of the liquid environment, thereby yielding free energies and thermodynamic averages directly, while eliminating the need for explicit consideration of the solvent electrons. We have implemented and tested this approach within the CASINO Quantum Monte Carlo code. Our method is suitable for calculations in any basis within CASINO, including b-spline and plane wave trial wavefunctions, and is equally applicable to molecules, surfaces, and crystals. For our preliminary test calculations, we use a simplified description of the solvent in terms of an isodensity continuum dielectric solvation approach, though the method is fully compatible with more reliable descriptions of the solvent we shall employ in the future.

Rapid method for the quantification of hydroquinone concentration: chemiluminescent analysis.

PubMed

Chen, Tung-Sheng; Liou, Show-Yih; Kuo, Wei-Wen; Wu, Hsi-Chin; Jong, Gwo-Ping; Wang, Hsueh-Fang; Shen, Chia-Yao; Padma, V Vijaya; Huang, Chih-Yang; Chang, Yen-Lin

2015-11-01

Topical hydroquinone serves as a skin whitener and is usually available in cosmetics or on prescription based on the hydroquinone concentration. Quantification of hydroquinone content therefore becomes an important issue in topical agents. High-performance liquid chromatography (HPLC) is the commonest method for determining hydroquinone content in topical agents, but this method is time-consuming and uses many solvents that can become an environmental issue. We report a rapid method for quantifying hydroquinone content by chemiluminescent analysis. Hydroquinone induces the production of hydrogen peroxide in the presence of basic compounds. Hydrogen peroxide induced by hydroquinone oxidized light-emitting materials such as lucigenin, resulted in the production of ultra-weak chemiluminescence that was detected by a chemiluminescence analyzer. The intensity of the chemiluminescence was found to be proportional to the hydroquinone concentration. We suggest that the rapid (measurement time, 60 s) and virtually solvent-free (solvent volume, <2 mL) chemiluminescent method described here for quantifying hydroquinone content may be an alternative to HPLC analysis. Copyright © 2015 John Wiley & Sons, Ltd.

Analysis of biomolecular solvation sites by 3D-RISM theory.

PubMed

Sindhikara, Daniel J; Hirata, Fumio

2013-06-06

We derive, implement, and apply equilibrium solvation site analysis for biomolecules. Our method utilizes 3D-RISM calculations to quickly obtain equilibrium solvent distributions without either necessity of simulation or limits of solvent sampling. Our analysis of these distributions extracts highest likelihood poses of solvent as well as localized entropies, enthalpies, and solvation free energies. We demonstrate our method on a structure of HIV-1 protease where excellent structural and thermodynamic data are available for comparison. Our results, obtained within minutes, show systematic agreement with available experimental data. Further, our results are in good agreement with established simulation-based solvent analysis methods. This method can be used not only for visual analysis of active site solvation but also for virtual screening methods and experimental refinement.

Dissolution of cellulose in ionic liquid: A review

NASA Astrophysics Data System (ADS)

Mohd, N.; Draman, S. F. S.; Salleh, M. S. N.; Yusof, N. B.

2017-02-01

Dissolution of cellulose with ionic liquids (IL) and deep eutectic solvent (DES) lets the comprehensive dissolution of cellulose. Basically, cellulose can be dissolved, in some hydrophilic ionic liquids, such as 1-butyl-3-methylimidazolium chloride (BMIMCl) and 1-allyl-3-methylimidazolium chloride (AMIMCl). Chloride based ionic liquids are suitable solvents for cellulose dissolution. Although the ILs is very useful in fine chemical industry, its application in the pharmaceutical and food industry have been very limited due to issues with toxicity, purity, and high cost. Seeing to these limitations, new green alternative solvent which is DES was used. This green solvents, may be definitely treated as the next-generation reagents for more sustainable industrial development. Thus, this review aims to discuss the dissolution of cellulose either with ionic liquids or DES and its application.

Conjugated Polymers Atypically Prepared in Water

PubMed Central

Invernale, Michael A.; Pendergraph, Samuel A.; Yavuz, Mustafa S.; Ombaba, Matthew; Sotzing, Gregory A.

2010-01-01

Processability remains a fundamental issue for the implementation of conducting polymer technology. A simple synthetic route towards processable precursors to conducting polymers (main chain and side chain) was developed using commercially available materials. These soluble precursor systems were converted to conjugated polymers electrochemically in aqueous media, offering a cheaper and greener method of processing. Oxidative conversion in aqueous and organic media each produced equivalent electrochromics. The precursor method enhances the yield of the electrochromic polymer obtained over that of electrodeposition, and it relies on a less corruptible electrolyte bath. However, electrochemical conversion of the precursor polymers often relies on organic salts and solvents. The ability to achieve oxidative conversion in brine offers a less costly and a more environmentally friendly processing step. It is also beneficial for biological applications. The electrochromics obtained herein were evaluated for electronic, spectral, and morphological properties. PMID:20959869

Revisiting Hansen Solubility Parameters by Including Thermodynamics.

PubMed

Louwerse, Manuel J; Maldonado, Ana; Rousseau, Simon; Moreau-Masselon, Chloe; Roux, Bernard; Rothenberg, Gadi

2017-11-03

The Hansen solubility parameter approach is revisited by implementing the thermodynamics of dissolution and mixing. Hansen's pragmatic approach has earned its spurs in predicting solvents for polymer solutions, but for molecular solutes improvements are needed. By going into the details of entropy and enthalpy, several corrections are suggested that make the methodology thermodynamically sound without losing its ease of use. The most important corrections include accounting for the solvent molecules' size, the destruction of the solid's crystal structure, and the specificity of hydrogen-bonding interactions, as well as opportunities to predict the solubility at extrapolated temperatures. Testing the original and the improved methods on a large industrial dataset including solvent blends, fit qualities improved from 0.89 to 0.97 and the percentage of correct predictions rose from 54 % to 78 %. Full Matlab scripts are included in the Supporting Information, allowing readers to implement these improvements on their own datasets. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

New insights into liquid chromatography for more eco-friendly analysis of pharmaceuticals.

PubMed

Shaaban, Heba

2016-10-01

Greening the analytical methods used for analysis of pharmaceuticals has been receiving great interest aimed at eliminating or minimizing the amount of organic solvents consumed daily worldwide without loss in chromatographic performance. Traditional analytical LC techniques employed in pharmaceutical analysis consume tremendous amounts of hazardous solvents and consequently generate large amounts of waste. The monetary and ecological impact of using large amounts of solvents and waste disposal motivated the analytical community to search for alternatives to replace polluting analytical methodologies with clean ones. In this context, implementing the principles of green analytical chemistry (GAC) in analytical laboratories is highly desired. This review gives a comprehensive overview on different green LC pathways for implementing GAC principles in analytical laboratories and focuses on evaluating the greenness of LC analytical procedures. This review presents green LC approaches for eco-friendly analysis of pharmaceuticals in industrial, biological, and environmental matrices. Graphical Abstract Green pathways of liquid chromatography for more eco-friendly analysis of pharmaceuticals.

The GSFC Combined Approach of ODC Stockpiling and Tribological Testing to Mitigate the Risks of ODC Elimination

NASA Technical Reports Server (NTRS)

Predmore, Roamer; Woods, Claudia; Hovanec, Andrew

1997-01-01

In response to the elimination of production of several Ozone Depleting Chemicals (ODCs) which have been widely used in successful space flight mechanism cleaning and lubricating procedures, GSFC developed and implemented an overall philosophy of mitigating the risks to flight hardware during the transition phase to ODC-Free cleaning procedures. One leg of that philosophy is the initiation of a several tier testing program which will deliver increasing amounts of information over the next few years, starting with original surface analysis comparisons between ODC and various ODC-Free cleaning technologies. The other leg is the stockpiling of an appropriate amount of ODC solvents such that all short term GSFC missions will be able to stay with or revert to heritage cleaning and lubricating procedures in the face of life issues. While tribological testing, mechanism life testing and space-flight experience will ultimately bring us into the 21st century with environmentally friendly means of cleaning long-life precision mechanism components, many satellites will be launched over the next few years with a number of important tribological questions unanswered. In order to prepare for this challenge, the Materials Engineering Branch in cooperation with the Electromechanical Branch launched an intensive review of all ongoing missions. The failure risk was determined for each long-life mechanism based on a number of parameters, including a comparison of flight solvents used to clean the heritage/life test hardware. Also studied was the ability of the mechanism manufacturers to stockpile ODCs based on state laws and company policies. A stockpiling strategy was constructed based on this information and subsequently implemented. This paper provides an overview of the GSFC ODC elimination risk mitigation philosophy as well as a detailed examination of the development of the ODC stockpiling plan.

From green chemistry to nature: The versatile role of low transition temperature mixtures.

PubMed

Durand, Erwann; Lecomte, Jérôme; Villeneuve, Pierre

2016-01-01

In 1998, the concept of "green chemistry" was established through twelve principles with the aim of improving the eco-efficiency of chemical processes and to judge, whether or not, a chemical process is sustainable. Currently, numerous processes do not obey to most of these principles (large energy usage, formation of waste, usage of hazardous solvents and reagents, etc …), which have forced the scientists to develop and implement new strategies for upcoming researches. One of the most attractive challenges is finding, creating and developing new and green media. Over the last decades, the scientific community has mainly focused on two different classes of solvents (namely, Ionic liquids and Eutectic Solvents). These solvents share advantageous characteristics (low vapor pressure, thermally stable, non-flammable, etc …) making them an attractive option to implement sustainable chemistry and engineering. Mainly due to its environmental and economic features, DES are now growing much more interest. Indeed, although their ecotoxicological profile is still poorly known, DES are classified as "green" solvents because they are composed of molecules which are considered to be eco-friendly. The fast, numerous and broad scope of studies on these new liquids make the literature rather complex to understand. Here, we attempted to establish a succinct history and a presentation of these liquids with emphasis on their role, classification, importance and application in biological systems. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

Evaluation of the effect of extraction solvent and organ selection on the chemical profile of Astragalus spinosus using HPTLC- multivariate image analysis.

PubMed

Shawky, Eman; Selim, Dina A

2017-09-01

The evaluation of extraction protocols for untargeted and targeted metabolomics was implemented for root and aerial organs of Astragalus spinosus in this work. The efficiency and complementarity of commonly used extraction solvents, namely petroleum ether, methylene chloride, ethyl acetate and n-butanol were considered for method evaluation using chemometric techniques in conjunction with new, simple, and fast high performance thin layer chromatography (HPTLC) method for fingerprint analysis by extracting information from a digitalized HPTLC plate using ImageJ software. A targeted approach was furtherly implemented by developing and validating an HPTLC method allowing the quantification of three saponin glycosides. The results of untargeted and targeted principle component analysis (PCA) and hierarchical cluster analysis (HCA) revealed that the apparent saponins profile seems to depend on a combined effect of matrix composition and the properties of the selected solvent for extraction, where both the biological matrix of the investigated plant organs, as well as the extraction solvent can influence the precision of metabolite abundances. Although, the aerial part is frequently discarded as waste, it is shown hereby that it has similar chemical profile compared to the medicinal part, roots, yet a different extraction solvents pattern is recognized between the two organs which can be attributed to the differences in the composition, permeability or accessibility of the sample matrix/organ tissues, rather than the chemical structures of the detected metabolites. Copyright © 2017 Elsevier B.V. All rights reserved.

Implementation of a solvent management program to control paint shop volatile organic compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Floer, M.M.; Hicks, B.H.

1997-12-31

The majority of automobile assembly plant volatile organic compound (VOC) emissions are generated from painting operations. Typical paint operations generate more than 90 percent of the total plant emissions and, up to, 50 percent can be released by cleaning sources. Plant practices which contribute to the release of VOC emissions include the cleaning of paint lines and equipment, tanks, spray booths, floors and vehicles. Solvents continue to be the largest contributing source of VOC emissions in an automotive paint shop. To reduce overall VOC emissions, environmental regulations and guidelines were introduced under the Clean Air Act; Pollution Prevention and Wastemore » Minimization programs, Control Techniques, and special air permit conditions. The introduction of these regulations and guidelines has driven industry toward continual refinement of their present cleaning methods while pursuing new techniques and technologies. Industry has also shown a proactive approach by introducing new waterborne and powder coating paint technologies to reduce overall emissions. As new paint technologies are developed and introduced, special attention must be given to the types of materials utilized for cleaning. The development and implementation of a solvent management program allows a facility to standardize a program to properly implement materials, equipment, technologies and work practices to reduce volatile organic compound emissions, meet strict cleaning requirements posed by new paint technologies and produce a vehicle which meets the high quality standards of the customer. This paper will assess the effectiveness of a solvent management program by examining pollution prevention initiatives and data from four different painting operations.« less

Pilot-Scale Silicone Process for Low-Cost Carbon Dioxide Capture. Final Scientific/Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hancu, Dan; Wood, Benjamin; Genovese, Sarah

GE Global Research has developed, over the last 8 years, a platform of cost effective CO 2 capture technologies based on a non-aqueous aminosilicone solvent (GAP-1m). As demonstrated in a previous funded DOE project (DE-FE0007502), the GAP-1m solvent has increased CO 2 working capacity, lower volatility and corrosivity than the benchmark aqueous amine technology. The current report describes the cooperative program between GE Global Research (GE GRC), and the National Carbon Capture Center (NCCC) to design, construct, and operate a pilot-scale process using GAP-1m solvent to demonstrate its performance at 0.5 MWe. (i) Performance of the GAP-1m solvent was demonstratedmore » in a 0.5 MWe pilot with real flue gas for over 900 hrs. of operation using two alternative desorption designs: a Continuous Stirred Tank Reactor (CSTR), and a Steam Stripper Column (SSC). The CSTR is a one-stage separation unit with reduced space requirements, and capital cost. The alternative is a multi-stage separation column, with improved desorption efficiency. Testing the two desorber options allowed us to identify the most cost effective, and space efficient desorber solution. (ii) CSTR Campaign: The CSTR desorber unit was designed, fabricated and integrated with the pilot solvent test unit (PSTU), replacing the PSTU Steam Stripper Column at NCCC. Solvent management and waste water special procedures were implemented to accommodate operation of the non-aqueous solvent in the PSTU. Performance of the GAP-1m solvent with the CSTR was demonstrated for over 500 hrs. while varying temperature of the desorption (230 – 265 oF), solvent circulation rate (GAP-1m : CO 2 (molar) = 1.5 – 4), and flue gas flow rates (0.2 – 0.5 MWe). Solvent carry-over in the CO 2 product was minimized by maintaining water content below 5 wt.%, and desorption pressure at 7 psig. CO 2 capture efficiency achieved was 95% at 0.25 MWe (GAP-1m : CO 2 = 4 (molar), 230 oF desorption), and 65% at 0.5 MWe (GAP-1m : CO 2 (molar) = 1.5, 248 oF). Solvent loss was dominated by thermal degradation of the rich solvent. (iii) Steam Stripper Column Campaign: Higher expected cost of the solvent vs. aqueous amines makes solvent management a top priority to maintain the low cost for the process. During the testing of the GAP-1m solvent with the CSTR, thermal degradation of the rich solvent was found to be the main mechanism in solvent loss. Small amounts of water in the working solution were found to be an effective way to enable steam stripping, thereby lowering desorption temperature, and hence reducing thermal degradation. Steam stripping also increased working capacity by 30% due to a more efficient desorption. The concept was first tested in a glass stripping column (lab scale, GE GRC), optimized in a continuous bench scale system (2 kWe, GE GRC), and demonstrated in a 0.5 MWe PSTU at NCCC. No special system modifications were required to the PSTU to accommodate the testing of the non-aqueous GAP-1 solvent with the regenerator column. SSC was found to be more robust towards solvent entrainment (H 2O < 35 wt.%). 90 – 95% CO 2 capture efficiency was achieved under stoichiometric conditions at 0.5 MWe (235 oF desorption, 2 psig and 19 wt. % H 2O). Both CO 2 capture efficiency and specific duty reached optimum conditions at 18 wt.% H 2O. Low amine degradation (< 0.05 wt.%/day) was recorded over 350 hrs. of operation. Controlled water addition to GAP-1m solvent decreased the desorption temperature, thermal degradation, and improved the CO 2 working capacity due to more efficient absorption and desorption processes. Under these conditions, the GAP-1m solvent exhibited a 25% increased working capacity, and 10% reduction in specific steam duty vs. MEA, at 10 oF lower desorption temperature. (iv) Techno-economic Analysis: The pilot-scale PSTU engineering data were used to update the capture system process models, and the techno-economic analysis was performed for a 550 MW coal fired power plant. The 1st year CO 2 removal cost for the aminosilicone-based carbon-capture process was evaluated at $48/ton CO 2 using the steam stripper column. This is a 20% reduction compared to MEA, primarily due to lower overall capital cost. CO 2 cost using the CSTR desorber is dominated by the economics of the solvent make-up. The steam stripper desorber is the preferred unit operation due to a more efficient desorption, and reduced solvent make-up rate. Further reduction in CO 2 capture cost is expected by lowering the manufacturing cost of the solvent, implementing flowsheet optimization and/or implementing the next generation aminosilicone solvent with improved stability and increased CO 2 working capacity.« less

Stochastic level-set variational implicit-solvent approach to solute-solvent interfacial fluctuations

PubMed Central

Zhou, Shenggao; Sun, Hui; Cheng, Li-Tien; Dzubiella, Joachim; McCammon, J. Andrew

2016-01-01

Recent years have seen the initial success of a variational implicit-solvent model (VISM), implemented with a robust level-set method, in capturing efficiently different hydration states and providing quantitatively good estimation of solvation free energies of biomolecules. The level-set minimization of the VISM solvation free-energy functional of all possible solute-solvent interfaces or dielectric boundaries predicts an equilibrium biomolecular conformation that is often close to an initial guess. In this work, we develop a theory in the form of Langevin geometrical flow to incorporate solute-solvent interfacial fluctuations into the VISM. Such fluctuations are crucial to biomolecular conformational changes and binding process. We also develop a stochastic level-set method to numerically implement such a theory. We describe the interfacial fluctuation through the “normal velocity” that is the solute-solvent interfacial force, derive the corresponding stochastic level-set equation in the sense of Stratonovich so that the surface representation is independent of the choice of implicit function, and develop numerical techniques for solving such an equation and processing the numerical data. We apply our computational method to study the dewetting transition in the system of two hydrophobic plates and a hydrophobic cavity of a synthetic host molecule cucurbit[7]uril. Numerical simulations demonstrate that our approach can describe an underlying system jumping out of a local minimum of the free-energy functional and can capture dewetting transitions of hydrophobic systems. In the case of two hydrophobic plates, we find that the wavelength of interfacial fluctuations has a strong influence to the dewetting transition. In addition, we find that the estimated energy barrier of the dewetting transition scales quadratically with the inter-plate distance, agreeing well with existing studies of molecular dynamics simulations. Our work is a first step toward the inclusion of fluctuations into the VISM and understanding the impact of interfacial fluctuations on biomolecular solvation with an implicit-solvent approach. PMID:27497546

Electrostatics of proteins in dielectric solvent continua. II. Hamiltonian reaction field dynamics

NASA Astrophysics Data System (ADS)

Bauer, Sebastian; Tavan, Paul; Mathias, Gerald

2014-03-01

In Paper I of this work [S. Bauer, G. Mathias, and P. Tavan, J. Chem. Phys. 140, 104102 (2014)] we have presented a reaction field (RF) method, which accurately solves the Poisson equation for proteins embedded in dielectric solvent continua at a computational effort comparable to that of polarizable molecular mechanics (MM) force fields. Building upon these results, here we suggest a method for linearly scaling Hamiltonian RF/MM molecular dynamics (MD) simulations, which we call "Hamiltonian dielectric solvent" (HADES). First, we derive analytical expressions for the RF forces acting on the solute atoms. These forces properly account for all those conditions, which have to be self-consistently fulfilled by RF quantities introduced in Paper I. Next we provide details on the implementation, i.e., we show how our RF approach is combined with a fast multipole method and how the self-consistency iterations are accelerated by the use of the so-called direct inversion in the iterative subspace. Finally we demonstrate that the method and its implementation enable Hamiltonian, i.e., energy and momentum conserving HADES-MD, and compare in a sample application on Ac-Ala-NHMe the HADES-MD free energy landscape at 300 K with that obtained in Paper I by scanning of configurations and with one obtained from an explicit solvent simulation.

Safety management of an underground-based gravitational wave telescope: KAGRA

NASA Astrophysics Data System (ADS)

Ohishi, Naoko; Miyoki, Shinji; Uchiyama, Takashi; Miyakawa, Osamu; Ohashi, Masatake

2014-08-01

KAGRA is a unique gravitational wave telescope with its location underground and use of cryogenic mirrors. Safety management plays an important role for secure development and operation of such a unique and large facility. Based on relevant law in Japan, Labor Standard Act and Industrial Safety and Health Law, various countermeasures are mandated to avoid foreseeable accidents and diseases. In addition to the usual safety management of hazardous materials, such as cranes, organic solvents, lasers, there are specific safety issues in the tunnel. Prevention of collapse, flood, and fire accidents are the most critical issues for the underground facility. Ventilation is also important for prevention of air pollution by carbon monoxide, carbon dioxide, organic solvents and radon. Oxygen deficiency should also be prevented.

Improved Detection Technique for Solvent Rinse Cleanliness Verification

NASA Technical Reports Server (NTRS)

Hornung, S. D.; Beeson, H. D.

2001-01-01

The NASA White Sands Test Facility (WSTF) has an ongoing effort to reduce or eliminate usage of cleaning solvents such as CFC-113 and its replacements. These solvents are used in the final clean and cleanliness verification processes for flight and ground support hardware, especially for oxygen systems where organic contaminants can pose an ignition hazard. For the final cleanliness verification in the standard process, the equivalent of one square foot of surface area of parts is rinsed with the solvent, and the final 100 mL of the rinse is captured. The amount of nonvolatile residue (NVR) in the solvent is determined by weight after the evaporation of the solvent. An improved process of sampling this rinse, developed at WSTF, requires evaporation of less than 2 mL of the solvent to make the cleanliness verification. Small amounts of the solvent are evaporated in a clean stainless steel cup, and the cleanliness of the stainless steel cup is measured using a commercially available surface quality monitor. The effectiveness of this new cleanliness verification technique was compared to the accepted NVR sampling procedures. Testing with known contaminants in solution, such as hydraulic fluid, fluorinated lubricants, and cutting and lubricating oils, was performed to establish a correlation between amount in solution and the process response. This report presents the approach and results and discusses the issues in establishing the surface quality monitor-based cleanliness verification.

76 FR 9656 - Approval and Promulgation of the Air Quality Implementation Plans; Maryland; Control of Volatile...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-22

... Promulgation of the Air Quality Implementation Plans; Maryland; Control of Volatile Organic Compound Emissions From Industrial Solvent Cleaning Operations AGENCY: Environmental Protection Agency (EPA). ACTION... Plan (SIP). The revision was submitted by the Maryland Department of the Environment (MDE) to establish...

Green extraction of grape skin phenolics by using deep eutectic solvents.

PubMed

Cvjetko Bubalo, Marina; Ćurko, Natka; Tomašević, Marina; Kovačević Ganić, Karin; Radojčić Redovniković, Ivana

2016-06-01

Conventional extraction techniques for plant phenolics are usually associated with high organic solvent consumption and long extraction times. In order to establish an environmentally friendly extraction method for grape skin phenolics, deep eutectic solvents (DES) as a green alternative to conventional solvents coupled with highly efficient microwave-assisted and ultrasound-assisted extraction methods (MAE and UAE, respectively) have been considered. Initially, screening of five different DES for proposed extraction was performed and choline chloride-based DES containing oxalic acid as a hydrogen bond donor with 25% of water was selected as the most promising one, resulting in more effective extraction of grape skin phenolic compounds compared to conventional solvents. Additionally, in our study, UAE proved to be the best extraction method with extraction efficiency superior to both MAE and conventional extraction method. The knowledge acquired in this study will contribute to further DES implementation in extraction of biologically active compounds from various plant sources. Copyright © 2016 Elsevier Ltd. All rights reserved.

ODC-Free Solvent Implementation for Phenolics Cleaning

NASA Technical Reports Server (NTRS)

Wurth, Laura; Biegert, Lydia; Lamont, DT; McCool, Alex (Technical Monitor)

2001-01-01

During phenolic liner manufacture, resin-impregnated (pre-preg) bias tape of silica, glass, or carbon cloth is tape-wrapped, cured, machined, and then wiped with 1,1,1 tri-chloroethane (TCA) to remove contaminants that may have been introduced during machining and handling. Following the TCA wipe, the machined surface is given a resin wet-coat and over-wrapped with more prepreg and cured. A TCA replacement solvent for these wiping operations must effectively remove both surface contaminants, and sub-surface oils and greases while not compromising the integrity of this interface. Selection of a TCA replacement solvent for phenolic over-wrap interface cleaning began with sub-scale compatibility tests with cured phenolics. Additional compatibility tests included assessment of solvent retention in machined phenolic surfaces. Results from these tests showed that, while the candidate solvent did not degrade the cured phenolics, it was retained in higher concentrations than TCA in phenolic surfaces. This effect was most pronounced with glass and silica cloth phenolics with steep ply angles relative to the wiped surfaces.

Cosolvent effects on the drug release and depot swelling in injectable in situ depot-forming systems.

PubMed

Liu, Hui; Venkatraman, Subbu S

2012-05-01

Although injectable depot-forming solutions have been commercialized, the factors that influence the overall release kinetics from such systems are still not fully understood. In this work, we address the effect of cosolvent on the issue of excessive burst release of potent bioactives from injectable depot-forming solutions. Specifically, we have evaluated the influence of addition of a relatively hydrophobic cosolvent (triacetin) to more hydrophilic biocompatible solvents such as dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP) on the burst release. Drug release and solvent release results demonstrate that high burst release that occurred when only hydrophilic solvent was used as solvent was significantly reduced by adding triacetin as a cosolvent. The profiles of drug release were in good agreement with the profiles of the hydrophilic solvent DMSO or NMP release, and the suppression of the burst by triacetin addition is due to the suppression of the solvent release. Surprisingly, the swelling of the depot increased with triacetin amount and the depot morphology became more porous compared with the absence of triacetin. Usage of hydrophobic solvent as a cosolvent to reduce the burst release was shown to be more effective on the hydrophobic PdlLA depot and less effective on the relatively hydrophilic RG502 depot. Copyright © 2012 Wiley Periodicals, Inc.

Direct Push Optical Screening Tool for High-Resolution, Real-Time Mapping of Chlorinated Solvent DNAPL Architecture

DTIC Science & Technology

2016-04-01

due to higher densities, lower viscosities , and increased weathering (mass depletion) of residual chlorinated solvent DNAPL compared to those other...demonstration area can be generally classified as stratified layers of fine sand and silt with few clay layers. A silt layer was penetrated consistently at...toxic and carcinogenic. Another potential issue evaluated was that in plastic soils (stiff clays for example) there is potential for the thickness of

Guidance Protocol: Application of Nucleic Acid-Based Tools for Monitoring Monitored Natural Attenuation (MNA), Biostimulation, and Bioaugmentation at Chlorinated Solvent Sites

DTIC Science & Technology

2011-02-01

Reductive dechlorination is a promising process for biodegradation of chlorinated solvents. The successful field evaluation and implementation of the...population. These specialized bacteria use the chlorinated ethenes as electron acceptors and gain energy for growth from the reductive...This guidance protocol addresses the use of MBTs to quantitatively assess the Dhc population at chlorinated ethene sites and aims at providing

Hydrothermal liquefaction of de-oiled Jatropha curcas cake using Deep Eutectic Solvents (DESs) as catalysts and co-solvents.

PubMed

Alhassan, Yahaya; Kumar, Naveen; Bugaje, Idris M

2016-01-01

Biomass liquefaction using ionic liquids (ILs) as catalysts has received appreciable attention, in renewable fuels and chemicals production, recently. However, issues associated with the production cost, long reaction time and use of volatile solvents are undeniably challenging. Thus, Deep Eutectic Solvents (DESs) emerged as promising and potential ILs substitutes. The hydrothermal liquefaction of de-oiled Jatropha curcas cake was catalyzed by four synthesized DESs as catalysts and co-solvents for selective extraction. Proximate and ultimate analyses including ash, moisture and carbon contents of bio-crude produced varied slightly. The higher heating values found ranges from 21.15 ± 0.82 MJ/kg to 24.30 ± 0.98 MJ/kg. The bio-crude yields obtained using ChCl-KOH DES was 43.53 wt% and ChCl-p-TsOH DES was 38.31 wt%. Bio-crude yield using ChCl-FeCl3 DES was 30.80 wt%. It is suggested that, the selectivity of bio-crude could be improved, by using DESs as catalyst and co-solvent in HTL of biomass such as de-oiled J. curcas cake. Copyright © 2015 Elsevier Ltd. All rights reserved.

Computing the Absorption and Emission Spectra of 5-Methylcytidine in Different Solvents: A Test-Case for Different Solvation Models.

PubMed

Martínez-Fernández, L; Pepino, A J; Segarra-Martí, J; Banyasz, A; Garavelli, M; Improta, R

2016-09-13

The optical spectra of 5-methylcytidine in three different solvents (tetrahydrofuran, acetonitrile, and water) is measured, showing that both the absorption and the emission maximum in water are significantly blue-shifted (0.08 eV). The absorption spectra are simulated based on CAM-B3LYP/TD-DFT calculations but including solvent effects with three different approaches: (i) a hybrid implicit/explicit full quantum mechanical approach, (ii) a mixed QM/MM static approach, and (iii) a QM/MM method exploiting the structures issuing from molecular dynamics classical simulations. Ab-initio Molecular dynamics simulations based on CAM-B3LYP functionals have also been performed. The adopted approaches all reproduce the main features of the experimental spectra, giving insights on the chemical-physical effects responsible for the solvent shifts in the spectra of 5-methylcytidine and providing the basis for discussing advantages and limitations of the adopted solvation models.

An assessment of alternatives for replacing Freon 113 in bench type electrical circuit board cleaning at Fermi National Accelerator Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isakson, K.; Vessell, A.L.

1994-07-01

Fermilab is presently phasing out all solvents containing Freon-113 (CFC-113) as part of the continuing Waste Minimization Program. These solvents are used primarily in cleaning the flux off of electronic circuit boards after soldering, specifically in bench type work. Title VI of the Clean Air Act mandates a production phase-out for ozone depleting substances, like CFC-113, by the year 2000. Our study addresses this issue by evaluating and choosing alternative non-CFC solvents to replace the CFC-1 13 solvents at Fermilab. Several potential non-CFC cleaning solvents were tested. The evaluation took place in three parts: controlled experimental evaluation, chemical composition evaluation,more » and employee performed evaluation. First, we performed a controlled nine-step procedure with the potential solvents where each was evaluated in categories such as cleaning effectiveness, odor, residue, type of output and drying time. Next, we listed the chemical composition of each solvent. We noted which solvents contained hydrochlorofluorocarbons because they are targeted for phase-out in the future and will be recognized as interim solutions only. Finally, after preliminary testing, five solvents were chosen as the best options. These solvents were sent to be tested by Fermilab employees who use such materials. Their opinions are valuable not only because they are knowledgeable in this field, but also because they will be using the solvents chosen to replace the CFC-113 solvents. The results favored two ``best alternatives``: Safezone Solvent Flux Remover by Miller-Stephenson and E-Series CFC Free Flux-Off 2000 by Chemtech. Another possible solution also pursued is the no-clean solder option. In our study, we were not able to thoroughly investigate the many types of no-clean solders because of time and financial constraints. The testing that was done, however, showed that no-clean solder was a viable alternative in many cases.« less

Fourier Transform Infrared Spectroscopy and Multivariate Analysis for Online Monitoring of Dibutyl Phosphate Degradation Product in Tributyl Phosphate/n-Dodecane/Nitric Acid Solvent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tatiana G. Levitskaia; James M. Peterson; Emily L. Campbell

2013-12-01

In liquid–liquid extraction separation processes, accumulation of organic solvent degradation products is detrimental to the process robustness, and frequent solvent analysis is warranted. Our research explores the feasibility of online monitoring of the organic solvents relevant to used nuclear fuel reprocessing. This paper describes the first phase of developing a system for monitoring the tributyl phosphate (TBP)/n-dodecane solvent commonly used to separate used nuclear fuel. In this investigation, the effect of extraction of nitric acid from aqueous solutions of variable concentrations on the quantification of TBP and its major degradation product dibutylphosphoric acid (HDBP) was assessed. Fourier transform infrared (FTIR)more » spectroscopy was used to discriminate between HDBP and TBP in the nitric acid-containing TBP/n-dodecane solvent. Multivariate analysis of the spectral data facilitated the development of regression models for HDBP and TBP quantification in real time, enabling online implementation of the monitoring system. The predictive regression models were validated using TBP/n-dodecane solvent samples subjected to high-dose external ?-irradiation. The predictive models were translated to flow conditions using a hollow fiber FTIR probe installed in a centrifugal contactor extraction apparatus, demonstrating the applicability of the FTIR technique coupled with multivariate analysis for the online monitoring of the organic solvent degradation products.« less

Fourier Transform Infrared Spectroscopy and Multivariate Analysis for Online Monitoring of Dibutyl Phosphate Degradation Product in Tributyl Phosphate /n-Dodecane/Nitric Acid Solvent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levitskaia, Tatiana G.; Peterson, James M.; Campbell, Emily L.

2013-11-05

In liquid-liquid extraction separation processes, accumulation of organic solvent degradation products is detrimental to the process robustness and frequent solvent analysis is warranted. Our research explores feasibility of online monitoring of the organic solvents relevant to used nuclear fuel reprocessing. This paper describes the first phase of developing a system for monitoring the tributyl phosphate (TBP)/n-dodecane solvent commonly used to separate used nuclear fuel. In this investigation, the effect of extraction of nitric acid from aqueous solutions of variable concentrations on the quantification of TBP and its major degradation product dibutyl phosphoric acid (HDBP) was assessed. Fourier Transform Infrared Spectroscopymore » (FTIR) spectroscopy was used to discriminate between HDBP and TBP in the nitric acid-containing TBP/n-dodecane solvent. Multivariate analysis of the spectral data facilitated the development of regression models for HDBP and TBP quantification in real time, enabling online implementation of the monitoring system. The predictive regression models were validated using TBP/n-dodecane solvent samples subjected to the high dose external gamma irradiation. The predictive models were translated to flow conditions using a hollow fiber FTIR probe installed in a centrifugal contactor extraction apparatus demonstrating the applicability of the FTIR technique coupled with multivariate analysis for the online monitoring of the organic solvent degradation products.« less

PM101: intravenous amiodarone formulation changes can improve medication safety.

PubMed

Souney, Paul F; Cooper, Warren D; Cushing, Daniel J

2010-03-01

Intravenous amiodarone (A-IV) is used to manage ventricular and atrial arrhythmias. The current formulation uses polysorbate 80 and benzyl alcohol to maintain amiodarone in solution, and these co-solvents are linked with clinically-important adverse events and pharmaceutical incompatibilities. PM101 is a recently FDA-approved intravenous formulation of amiodarone that uses a cyclodextrin to solubilize amiodarone. This review describes the clinical and pharmaceutical development of formulations of amiodarone for intravenous administration. The medical and pharmaceutical literature was searched for papers discussing A-IV, PM101 and their formulation components. Relevant literature was identified starting from 1948 to the present. The reader will learn about the important medical and pharmaceutical issues complicating A-IV administration, including an understanding of related hypotension and compatibility with commonly used infusion materials and how these issues may impact drug safety. PM101 has been developed to address several of these important issues. PM101 is a new formulation of A-IV that is stable in commonly used infusion materials and avoids co-solvent related toxicities.

Achieving accurate compound concentration in cell-based screening: validation of acoustic droplet ejection technology.

PubMed

Grant, Richard John; Roberts, Karen; Pointon, Carly; Hodgson, Clare; Womersley, Lynsey; Jones, Darren Craig; Tang, Eric

2009-06-01

Compound handling is a fundamental and critical step in compound screening throughout the drug discovery process. Although most compound-handling processes within compound management facilities use 100% DMSO solvent, conventional methods of manual or robotic liquid-handling systems in screening workflows often perform dilutions in aqueous solutions to maintain solvent tolerance of the biological assay. However, the use of aqueous media in these applications can lead to suboptimal data quality due to compound carryover or precipitation during the dilution steps. In cell-based assays, this effect is worsened by the unpredictable physical characteristics of compounds and the low DMSO tolerance within the assay. In some cases, the conventional approaches using manual or automated liquid handling resulted in variable IC(50) dose responses. This study examines the cause of this variability and evaluates the accuracy of screening data in these case studies. A number of liquid-handling options have been explored to address the issues and establish a generic compound-handling workflow to support cell-based screening across our screening functions. The authors discuss the validation of the Labcyte Echo reformatter as an effective noncontact solution for generic compound-handling applications against diverse compound classes using triple-quad liquid chromatography/mass spectrometry. The successful validation and implementation challenges of this technology for direct dosing onto cells in cell-based screening is discussed.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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. Whilemore » 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 is the first volume of the two-volume final report and summarizes Budget Period 1 accomplishments under Tasks 1-5 of the project, including the selection of four solvent formulations for further study.« less

Results From The Salt Disposition Project Next Generation Solvent Demonstration Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peters, T. B.; Fondeur, F. F.; Taylor-Pashow, K. M.L.

2014-04-02

Strip Effluent Hold Tank (SEHT), Decontaminated Salt Solution Hold Tank (DSSHT), Caustic Wash Tank (CWT) and Solvent Hold Tank (SHT) samples were taken throughout the Next Generation Solvent (NGS) Demonstration Plan. These samples were analyzed and the results are reported. SHT: The solvent behaved as expected, with no bulk changes in the composition over time, with the exception of the TOA and TiDG. The TiDG depletion is higher than expected, and consideration must be taken on the required rate of replenishment. Monthly sampling of the SHT is warranted. If possible, additional SHT samples for TiDG analysis (only) would help SRNLmore » refine the TiDG degradation model. CWT: The CWT samples show the expected behavior in terms of bulk chemistry. The 137Cs deposited into the CWT varies somewhat, but generally appears to be lower than during operations with the BOBCalix solvent. While a few minor organic components were noted to be present in the Preliminary sample, at this time these are thought to be artifacts of the sample preparation or may be due to the preceding solvent superwash. DSSHT: The DSSHT samples show the predicted bulk chemistry, although they point towards significant dilution at the front end of the Demonstration. The 137Cs levels in the DSSHT are much lower than during the BOBCalix operations, which is the expected observation. SEHT: The SEHT samples represent the most different output of all four of the outputs from MCU. While the bulk chemistry is as expected, something is causing the pH of the SEHT to be higher than what would be predicted from a pure stream of 0.01 M boric acid. There are several possible different reasons for this, and SRNL is in the process of investigating. Other than the pH issue, the SEHT is as predicted. In summary, the NGS Demonstration Plan samples indicate that the MCU system, with the Blend Solvent, is operating as expected. The only issue of concern regards the pH of the SEHT, and SRNL is in the process of investigating this. SRNL results support the transition to routine operations.« less

Multiscale simulation of molecular processes in cellular environments.

PubMed

Chiricotto, Mara; Sterpone, Fabio; Derreumaux, Philippe; Melchionna, Simone

2016-11-13

We describe the recent advances in studying biological systems via multiscale simulations. Our scheme is based on a coarse-grained representation of the macromolecules and a mesoscopic description of the solvent. The dual technique handles particles, the aqueous solvent and their mutual exchange of forces resulting in a stable and accurate methodology allowing biosystems of unprecedented size to be simulated.This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'. © 2016 The Author(s).

Non-aqueous cleaning solvent substitution

NASA Technical Reports Server (NTRS)

Meier, Gerald J.

1994-01-01

A variety of environmental, safety, and health concerns exist over use of chlorinated and fluorinated cleaning solvents. Sandia National Laboratories, Lawrence Livermore National Laboratories, and the Kansas City Division of AlliedSignal have combined efforts to focus on finding alternative cleaning solvents and processes which are effective, environmentally safe, and compliant with local, state, and federal regulations. An alternative solvent has been identified, qualified, and implemented into production of complex electronic assemblies, where aqueous and semi-aqueous cleaning processes are not allowed. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, was selected as the solvent of choice, and it was found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data. The electronics industry is constantly searching for proven methods and environmentally-safe materials to use in manufacturing processes. The information in this presentation will provide another option to consider on future projects for applications requiring high levels of quality, reliability, and cleanliness from non-aqueous cleaning processes.

Initial solubility & density evaluation of Non-Aqueous system of amino acid salts for CO2 capture: potassium prolinate blended with ethanol and ethylene glycol

NASA Astrophysics Data System (ADS)

Murshid, Ghulam; Garg, Sahil

2018-05-01

Amine scrubbing is the state of the art technology for CO2 capture, and solvent selection can significantly reduce the capital and energy cost of the process. Higher energy requirement for aqueous amine based CO2 removal process is still a most important downside preventive its industrial deployment. Therefore, in this study, novel non-aqueous based amino acid salt system consisting of potassium prolinate, ethanol and ethylene glycol has been studied. This work presents initial CO2 solubility study and important physical properties i.e. density of the studied solvent system. Previous work showed that non-aqueous system of potassium prolinate and ethanol has good absorption rates and requires lower energy for solvent regeneration. However, during regeneration, solvent loss issues were found due to lower boiling point of the ethanol. Therefore, ethylene glycol was added into current studied system for enhancing the overall boiling point of the system. The good initial CO2 solubility and low density of studied solvent system offers several advantages as compared to conventional amine solutions.

Approaches to efficiently estimate solvation and explicit water energetics in ligand binding: the use of WaterMap [WaterMap and Its Implementation in Drug Discovery

DOE PAGES

Yang, Yue; Wong, Sergio E.; Lightstone, Felice C.

2012-09-08

Solvents play quite an important role in most chemical and biological processes. It is widely accepted that the presence of water or other solvents in many chemical reactions can result in much lower energy barrier. In enzymatic catalysis, water mediated reaction pathways have been observed in various studies. In addition, different conformation flexibility and hydrogen bond patterns have been discovered for cyclic peptides in the presence of membrane and water, further illustrating the impact of solvent in biological activities such like membrane penetration. moreover, as will be discussed later in this review, water also plays a critical role in host-guestmore » chemistry and thus is essential to drug design. As such, it is not surprising that accounting for solvents is critical in drug discovery since drugs must modulate biological systems.« less

An extensible framework for capturing solvent effects in computer generated kinetic models.

PubMed

Jalan, Amrit; West, Richard H; Green, William H

2013-03-14

Detailed kinetic models provide useful mechanistic insight into a chemical system. Manual construction of such models is laborious and error-prone, which has led to the development of automated methods for exploring chemical pathways. These methods rely on fast, high-throughput estimation of species thermochemistry and kinetic parameters. In this paper, we present a methodology for extending automatic mechanism generation to solution phase systems which requires estimation of solvent effects on reaction rates and equilibria. The linear solvation energy relationship (LSER) method of Abraham and co-workers is combined with Mintz correlations to estimate ΔG(solv)°(T) in over 30 solvents using solute descriptors estimated from group additivity. Simple corrections are found to be adequate for the treatment of radical sites, as suggested by comparison with known experimental data. The performance of scaled particle theory expressions for enthalpic-entropic decomposition of ΔG(solv)°(T) is also presented along with the associated computational issues. Similar high-throughput methods for solvent effects on free-radical kinetics are only available for a handful of reactions due to lack of reliable experimental data, and continuum dielectric calculations offer an alternative method for their estimation. For illustration, we model liquid phase oxidation of tetralin in different solvents computing the solvent dependence for ROO• + ROO• and ROO• + solvent reactions using polarizable continuum quantum chemistry methods. The resulting kinetic models show an increase in oxidation rate with solvent polarity, consistent with experiment. Further work needed to make this approach more generally useful is outlined.

Mechanisms of solvent resistance mediated by interplay of cellular factors in Pseudomonas putida.

PubMed

Ramos, Juan-Luis; Sol Cuenca, Maria; Molina-Santiago, Carlos; Segura, Ana; Duque, Estrella; Gómez-García, María R; Udaondo, Zulema; Roca, Amalia

2015-07-01

A number of microorganisms have the ability to thrive in the presence of a range of toxic solvents. Tolerance to these chemicals is a multifactorial process, meaning that bacterial cells use a set of physiological and gene expression changes to overcome the damage imparted by these chemicals. This review focuses mainly on issues related to tolerance to aromatic hydrocarbons and butanol in Pseudomonas, although other microorganisms are also discussed. Pseudomonas putida strains contain a circular chromosome of approximately 6 Mbp which encodes about 5300 genes. A combination of physiological and biochemical assays, a genome-wide collection of mutants and several omics approaches have provided useful information to help identify functions involved in solvent tolerance in P. putida. The solvent response involves fine-tuning of lipid fluidity to adjust membrane functions including impermeabilization, activation of a general stress-response system, increased energy generation and induction of specific efflux pumps that extrude solvents to the medium. These responses are modulated at the transcriptional level by local and global regulators as well as by a number of sRNAs whose levels fluctuate with the presence of solvents in the environment. Taken as a whole these regulatory inputs orchestrate the complex network of metabolic responses observed after solvent addition. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Enhanced fluidity liquid chromatography of inulin fructans using ternary solvent strength and selectivity gradients.

PubMed

Bennett, Raffeal; Olesik, Susan V

2018-01-25

The value of exploring selectivity and solvent strength ternary gradients in enhanced fluidity liquid chromatography (EFLC) is demonstrated for the separation of inulin-type fructans from chicory. Commercial binary pump systems for supercritical fluid chromatography only allow for the implementation of ternary solvent strength gradients which can be restrictive for the separation of polar polymeric analytes. In this work, a custom system was designed to extend the capability of EFLC to allow tuning of selectivity or solvent strength in ternary gradients. Gradient profiles were evaluated using the Berridge function (RF 1 ), normalized resolution product (NRP), and gradient peak capacity (P c ). Selectivity gradients provided the separation of more analytes over time. The RF 1 function showed favor to selectivity gradients with comparable P c to that of solvent strength gradients. NRP did not strongly correlate with P c or RF 1 score. EFLC with the hydrophilic interaction chromatography, HILIC, separation mode was successfully employed to separate up to 47 fructan analytes in less than 25 min using a selectivity gradient. Copyright © 2017 Elsevier B.V. All rights reserved.

Microwave-Assisted Condensation Reactions of Acetophenone Derivatives and Activated Methylene Compounds with Aldehydes Catalyzed by Boric Acid under Solvent-Free Conditions.

PubMed

Brun, Elodie; Safer, Abdelmounaim; Carreaux, François; Bourahla, Khadidja; L'helgoua'ch, Jean-Martial; Bazureau, Jean-Pierre; Villalgordo, Jose Manuel

2015-06-23

We here disclosed a new protocol for the condensation of acetophenone derivatives and active methylene compounds with aldehydes in the presence of boric acid under microwave conditions. Implementation of the reaction is simple, healthy and environmentally friendly owing to the use of a non-toxic catalyst coupled to a solvent-free procedure. A large variety of known or novel compounds have thus been prepared, including with substrates bearing acid or base-sensitive functional groups.

A Novel Mechanism for Chemical Sensing Based on Solvent-Fluorophore-Substrate Interaction: Highly Selective Alcohol and Water Sensor with Large Fluorescence Signal Contrast.

PubMed

Chung, Kyeongwoon; Yang, Da Seul; Jung, Jaehun; Seo, Deokwon; Kwon, Min Sang; Kim, Jinsang

2016-10-06

Differentiation of solvents having similar physicochemical properties, such as ethanol and methanol, is an important issue of interest. However, without performing chemical analyses, discrimination between methanol and ethanol is highly challenging due to their similarity in chemical structure as well as properties. Here, we present a novel type of alcohol and water sensor based on the subtle differences in interaction among solvent analytes, fluorescent organic molecules, and a mesoporous silica gel substrate. A gradual change in the chemical structure of the fluorescent diketopyrrolopyrrole (DPP) derivatives alters their interaction with the substrate and solvent analyte, which creates a distinct intermolecular aggregation of the DPP derivatives on the silica gel substrate depending on the solvent environment and produces a change in the fluorescence color and intensity as a sensory signal. The devised sensor device, which is fabricated with simple drop-casting of the DPP derivative solutions onto a silica gel substrate, exhibited a completely reversible fluorescence signal change with large fluorescence signal contrast, which allows selective solvent detection by simple optical observation with the naked eye under UV light. Superior selectivity of the alcohol and water sensor system, which can clearly distinguish among ethanol, methanol, ethylene glycol, and water, is demonstrated.

The link between a negative high resolution resist contrast/developer performance and the Flory-Huggins parameter estimated from the Hansen solubility sphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

StCaire, Lorri; Olynick, Deirdre L.; Chao, Weilun L.

We have implemented a technique to identify candidate polymer solvents for spinning, developing, and rinsing for a high resolution, negative electron beam resist hexa-methyl acetoxy calix(6)arene to elicit the optimum pattern development performance. Using the three dimensional Hansen solubility parameters for over 40 solvents, we have constructed a Hansen solubility sphere. From this sphere, we have estimated the Flory Huggins interaction parameter for solvents with hexa-methyl acetoxy calix(6)arene and found a correlation between resist development contrast and the Flory-Huggins parameter. This provides new insights into the development behavior of resist materials which are necessary for obtaining the ultimate lithographic resolution.

Microscopic relaxations in a protein sustained down to 160K in a non-glass forming organic solvent.

PubMed

Mamontov, E; O'Neill, H

2017-01-01

We have studied microscopic dynamics of a protein in carbon disulfide, a non-glass forming solvent, down to its freezing temperature of ca. 160K. We have utilized quasielastic neutron scattering. A comparison of lysozyme hydrated with water and dissolved in carbon disulfide reveals a stark difference in the temperature dependence of the protein's microscopic relaxation dynamics induced by the solvent. In the case of hydration water, the common protein glass-forming solvent, the protein relaxation slows down in response to a large increase in the water viscosity on cooling down, exhibiting a well-known protein dynamical transition. The dynamical transition disappears in non-glass forming carbon disulfide, whose viscosity remains a weak function of temperature all the way down to freezing at just below 160K. The microscopic relaxation dynamics of lysozyme dissolved in carbon disulfide is sustained down to the freezing temperature of its solvent at a rate similar to that measured at ambient temperature. Our results demonstrate that protein dynamical transition is not merely solvent-assisted, but rather solvent-induced, or, more precisely, is a reflection of the temperature dependence of the solvent's glass-forming dynamics. We hypothesize that, if the long debated idea regarding the direct link between the microscopic relaxations and the biological activity in proteins is correct, then not only the microscopic relaxations, but also the activity, could be sustained in proteins all the way down to the freezing temperature of a non-glass forming solvent with a weak temperature dependence of its viscosity. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultra-lightweight and highly porous carbon aerogels from bamboo pulp fibers as an effective sorbent for water treatment

NASA Astrophysics Data System (ADS)

Yuan, Wei; Zhang, Xiaofang; Zhao, Jiangqi; Li, Qingye; Ao, Chenghong; Xia, Tian; Zhang, Wei; Lu, Canhui

Sorbents derived from biomass provide a novel approach to settle issues of organic solvent and/or oil leakage. In this work, a novel carbon aerogel (CA) was prepared as sorbents using the cheap and abundant bamboo pulp fibers as precursors through the pyrolysis method. The CA displayed an ultra-low density (5.65 mg cm-3), high hydrophobicity (water contact angle of 135.9°) and a large specific surface area (379.39 m2 g-1) as well as great mechanical properties. The absorption capacities of CA for organic solvents/oils were extraordinary (50-150 g/g). Particularly, its absorption on organic solvents was superior to many other bio-based CAs. The reusability of CA was also found impressive. For over five absorption-desorption cycles, the CA still showed excellent absorption behaviors on organic solvents and oils. Importantly, the fabrication process of CA is quite simple and environmentally friendly, demonstrating high potentials for future water treatment applications.

DNAPL SITE EVALUATION - Project Summary

EPA Science Inventory

Dense nonaqueous-phase liquids (DNAPLs), especially chlorinated solvents, are among the most prevalent subsurface contaminants identified in ground-water supplies and at waste disposal sites. There are several site-characterization issues specific to DNAPL sites including (a) the...

[Neurologic diagnosis and certification in persons chronically exposed to certain organic solvents in light of personal cases].

PubMed

Sińczuk-Walczak, H

1995-01-01

A clinical picture of selected cases diagnosed or suspected of chronic poisoning by organic solvents such as: Trichlorethylene (TRI), Tetrachlorethylene (PER), Carbon Disulfide (CS2) is presented. Based on examples of diagnosed neurological syndromes, some diagnostic and certification issues concerning occupational diseases of the neurological system, are analysed. An objective assessment of patients' complaints, differentiation between occupational diseases, so called idiopathic diseases of the nervous system, selection of appropropriate diagnostic methods in order to confirm or exclude these diseases belong to essential problems among those discussed.

Hemin-utilizing G-quadruplex DNAzymes are strongly active in organic co-solvents.

PubMed

Canale, Thomas D; Sen, Dipankar

2017-05-01

The widespread use of organic solvents in industrial processes has focused in recent years on the utility of "green" solvents - those with less harmful environmental, health, and safety properties - such as methanol and formamide. However, protein enzymes, regarded as green catalysts, are often incompatible with organic solvents. Herein, we have explored the oxidative properties of a Fe(III)-heme, or hemin, utilizing catalytic DNA (heme·DNAzyme) in different green solvent-water mixtures. We find that the peroxidase and peroxygenase activities of the heme·DNAzyme are strongly enhanced in 20-30% v/v methanol or formamide, relative to water alone. Protic solvent content of >30% v/v gradually diminishes heme·DNAzyme catalytic activity; however, the heme·DNAzyme is still active in as high as 80% v/v methanol. In contrast to protic solvents, aqueous dimethylformamide solutions largely inhibit heme·DNAzyme activity. In view of the strong catalytic activity of heme·DNAzyme in aqueous methanol, we were able to determine that a 60% v/v methanol-water mixture gives the most optimal yield of the dibenzothiophene sulfoxide (DBTO) oxidation product of petroleum-derived dibenzothiophene (DBT). The high product yield reflects both DNAzyme catalysis and a high substrate availability. Overall, these results emphasize the excellent promise of G-quadruplex forming DNA catalysts in application to "greener" industrial chemistry. This article is part of a Special Issue entitled "G-quadruplex" Guest Editor: Dr. Concetta Giancola and Dr. Daniela Montesarchio. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical Engineering in the Spectrum of Knowledge.

ERIC Educational Resources Information Center

Sutija, Davor P.; Prausnitz, John M.

1990-01-01

Provides three classroom examples showing students how chemical engineering techniques can supply partial answers to social questions, such as environmental issues. Examples are depletion of the ozone layer, nuclear winter, and air pollution by chemical solvents. (YP)

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 lessmore » 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.« less

Improving the Efficiency of Non-equilibrium Sampling in the Aqueous Environment via Implicit-Solvent Simulations.

PubMed

Liu, Hui; Chen, Fu; Sun, Huiyong; Li, Dan; Hou, Tingjun

2017-04-11

By means of estimators based on non-equilibrium work, equilibrium free energy differences or potentials of mean force (PMFs) of a system of interest can be computed from biased molecular dynamics (MD) simulations. The approach, however, is often plagued by slow conformational sampling and poor convergence, especially when the solvent effects are taken into account. Here, as a possible way to alleviate the problem, several widely used implicit-solvent models, which are derived from the analytic generalized Born (GB) equation and implemented in the AMBER suite of programs, were employed in free energy calculations based on non-equilibrium work and evaluated for their abilities to emulate explicit water. As a test case, pulling MD simulations were carried out on an alanine polypeptide with different solvent models and protocols, followed by comparisons of the reconstructed PMF profiles along the unfolding coordinate. The results show that when employing the non-equilibrium work method, sampling with an implicit-solvent model is several times faster and, more importantly, converges more rapidly than that with explicit water due to reduction of dissipation. Among the assessed GB models, the Neck variants outperform the OBC and HCT variants in terms of accuracy, whereas their computational costs are comparable. In addition, for the best-performing models, the impact of the solvent-accessible surface area (SASA) dependent nonpolar solvation term was also examined. The present study highlights the advantages of implicit-solvent models for non-equilibrium sampling.

Organic single-crystal arrays from solution-phase growth using micropattern with nucleation control region.

PubMed

Goto, Osamu; Tomiya, Shigetaka; Murakami, Yosuke; Shinozaki, Akira; Toda, Akira; Kasahara, Jiro; Hobara, Daisuke

2012-02-21

A method for forming organic single-crystal arrays from solution is demonstrated using an organic semiconductor, 3,9-bis(4-ethylphenyl)-peri-xanthenoxanthene (C(2) Ph-PXX). Supersaturation of C(2) Ph-PXX/tetralin solution is spatially changed by making a large difference in solvent evaporation to generate nuclei at the designated location. The method is simple to implement since it employs only a micropattern and control of the solvent vapor pressure during growth. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

European solvent industry group generic exposure scenario risk and exposure tool

PubMed Central

Zaleski, Rosemary T; Qian, Hua; Zelenka, Michael P; George-Ares, Anita; Money, Chris

2014-01-01

The European Solvents Industry Group (ESIG) Generic Exposure Scenario (GES) Risk and Exposure Tool (EGRET) was developed to facilitate the safety evaluation of consumer uses of solvents, as required by the European Union Registration, Evaluation and Authorization of Chemicals (REACH) Regulation. This exposure-based risk assessment tool provides estimates of both exposure and risk characterization ratios for consumer uses. It builds upon the consumer portion of the European Center for Ecotoxicology and Toxicology of Chemicals (ECETOC) Targeted Risk Assessment (TRA) tool by implementing refinements described in ECETOC TR107. Technical enhancements included the use of additional data to refine scenario defaults and the ability to include additional parameters in exposure calculations. Scenarios were also added to cover all frequently encountered consumer uses of solvents. The TRA tool structure was modified to automatically determine conditions necessary for safe use. EGRET reports results using specific standard phrases in a format consistent with REACH exposure scenario guidance, in order that the outputs can be readily assimilated within safety data sheets and similar information technology systems. Evaluation of tool predictions for a range of commonly encountered consumer uses of solvents found it provides reasonable yet still conservative exposure estimates. PMID:23361440

European solvent industry group generic exposure scenario risk and exposure tool.

PubMed

Zaleski, Rosemary T; Qian, Hua; Zelenka, Michael P; George-Ares, Anita; Money, Chris

2014-01-01

The European Solvents Industry Group (ESIG) Generic Exposure Scenario (GES) Risk and Exposure Tool (EGRET) was developed to facilitate the safety evaluation of consumer uses of solvents, as required by the European Union Registration, Evaluation and Authorization of Chemicals (REACH) Regulation. This exposure-based risk assessment tool provides estimates of both exposure and risk characterization ratios for consumer uses. It builds upon the consumer portion of the European Center for Ecotoxicology and Toxicology of Chemicals (ECETOC) Targeted Risk Assessment (TRA) tool by implementing refinements described in ECETOC TR107. Technical enhancements included the use of additional data to refine scenario defaults and the ability to include additional parameters in exposure calculations. Scenarios were also added to cover all frequently encountered consumer uses of solvents. The TRA tool structure was modified to automatically determine conditions necessary for safe use. EGRET reports results using specific standard phrases in a format consistent with REACH exposure scenario guidance, in order that the outputs can be readily assimilated within safety data sheets and similar information technology systems. Evaluation of tool predictions for a range of commonly encountered consumer uses of solvents found it provides reasonable yet still conservative exposure estimates.

METHODS AND ANALYSES FOR IMPLEMENTING NATURAL ATTENUATION PROTOCOLS

EPA Science Inventory

Technical protocols for evaluating natural attenuation at petroleum hydrocarbon and chlorinated solvent contaminated sites specify the analysis of electron acceptors and metabolic by-products for identifying and quantifying natural attenuation processes. However, these protocols ...

Unraveling the solvent induced welding of silver nanowires for high performance flexible transparent electrodes.

PubMed

Zhang, Kui; Li, Jia; Fang, Yunsheng; Luo, Beibei; Zhang, Yanli; Li, Yanqiu; Zhou, Jun; Hu, Bin

2018-04-25

A solution processed metal nanowire network is a promising flexible transparent electrode to replace brittle metal oxides for printable optoelectronics applications, but suffers from the issue of pseudo contact between nanowires. Herein, using volatile solvent mists as a powerful "zipper", we demonstrate a simple and rapid method to effectively weld silver nanowires, which dramatically improves the conductivity and robustness of the silver nanowire network based flexible transparent electrodes. We reveal that for a stacked network structure, the unique wedge-shaped nanogaps between the long nanowires and substrate provide a strong capillary force during solvent evaporation, which is much larger than that between zero-dimensional nanoparticles and gives a decisive contribution for nanowire junction welding, and this nanowire-substrate interplay force is positively related to the wettability of the substrate. At the same time, the dissolution-reprecipitation of the capping agent on the silver nanowire surface as the natural adhesive can fix the network on the substrate tightly, which enhances the robustness of the network. Our approach solves two key issues in solution-processed transparent electrodes in one simple step, and is compatible with various mild solution-processed optoelectronic devices, especially those containing heat-sensitive or chemical-sensitive materials. Moreover, a new type of invisible infrared encryption display is demonstrated based on this approach.

Annual waste reduction activities report. Issue 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1991-03-18

This report discusses the waste minimization activities for the Pinellas Plant. The Pinellas Plant deals with low-level radioactive wastes, solvents, scrap metals and various other hazardous materials. This program has realized cost savings through recycling and reuse of materials.

Methodology issues in implementation science.

PubMed

Newhouse, Robin; Bobay, Kathleen; Dykes, Patricia C; Stevens, Kathleen R; Titler, Marita

2013-04-01

Putting evidence into practice at the point of care delivery requires an understanding of implementation strategies that work, in what context and how. To identify methodological issues in implementation science using 4 studies as cases and make recommendations for further methods development. Four cases are presented and methodological issues identified. For each issue raised, evidence on the state of the science is described. Issues in implementation science identified include diverse conceptual frameworks, potential weaknesses in pragmatic study designs, and the paucity of standard concepts and measurement. Recommendations to advance methods in implementation include developing a core set of implementation concepts and metrics, generating standards for implementation methods including pragmatic trials, mixed methods designs, complex interventions and measurement, and endorsing reporting standards for implementation studies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Xuchu; Hu, Mary; Wei, Xiaoliang

Understanding the solvation structures of electrolytes is important for developing nonaqueous redox flow batteries that hold considerable potential for future large scale energy storage systems. The utilization of an emerging ionic-derivative ferrocene compounds, ferrocenylmethyl dimethyl ethyl ammonium bis (triflyoromethanesulfonyl)imide (Fc1N112-TFSI), has recently overcome the issue of solubility in the supporting electrolyte. In this work, 13C1H and 17O NMR investigations were carried out using solvent. It was observed that the spectra of 13C experience changes of chemical shifts while those of 17O undergo line width broadening, indicating interactions between solute and solvent molecules

Thermodynamic Approach to Boron Nitride Nanotube Solubility and Dispersion

NASA Technical Reports Server (NTRS)

Tiano, A. L.; Gibbons, L.; Tsui, M.; Applin, S. I.; Silva, R.; Park, C.; Fay, C. C.

2016-01-01

Inadequate dispersion of nanomaterials is a critical issue that significantly limits the potential properties of nanocomposites and when overcome, will enable further enhancement of material properties. The most common methods used to improve dispersion include surface functionalization, surfactants, polymer wrapping, and sonication. Although these approaches have proven effective, they often achieve dispersion by altering the surface or structure of the nanomaterial and ultimately, their intrinsic properties. Co-solvents are commonly utilized in the polymer, paint, and art conservation industries to selectively dissolve materials. These co-solvents are utilized based on thermodynamic interaction parameters and are chosen so that the original materials are not affected. The same concept was applied to enhance the dispersion of boron nitride nanotubes (BNNTs) to facilitate the fabrication of BNNT nanocomposites. Of the solvents tested, dimethylacetamide (DMAc) exhibited the most stable, uniform dispersion of BNNTs, followed by N,N-dimethylformamide (DMF), acetone, and N-methyl-2-pyrrolidone (NMP). Utilizing the known Hansen solubility parameters of these solvents in comparison to the BNNT dispersion state, a region of good solubility was proposed. This solubility region was used to identify co-solvent systems that led to improved BNNT dispersion in poor solvents such as toluene, hexane, and ethanol. Incorporating the data from the co-solvent studies further refined the proposed solubility region. From this region, the Hansen solubility parameters for BNNTs are thought to lie at the midpoint of the solubility sphere: 16.8, 10.7, and 9.0 MPa(exp 1/2) for delta d, delta p, and delta h, respectively, with a calculated Hildebrand parameter of 21.8 MPa)exp 1/2).

Thermodynamic approach to boron nitride nanotube solubility and dispersion.

PubMed

Tiano, A L; Gibbons, L; Tsui, M; Applin, S I; Silva, R; Park, C; Fay, C C

2016-02-21

Inadequate dispersion of nanomaterials is a critical issue that significantly limits the potential properties of nanocomposites and when overcome, will enable further enhancement of material properties. The most common methods used to improve dispersion include surface functionalization, surfactants, polymer wrapping, and sonication. Although these approaches have proven effective, they often achieve dispersion by altering the surface or structure of the nanomaterial and ultimately, their intrinsic properties. Co-solvents are commonly utilized in the polymer, paint, and art conservation industries to selectively dissolve materials. These co-solvents are utilized based on thermodynamic interaction parameters and are chosen so that the original materials are not affected. The same concept was applied to enhance the dispersion of boron nitride nanotubes (BNNTs) to facilitate the fabrication of BNNT nanocomposites. Of the solvents tested, dimethylacetamide (DMAc) exhibited the most stable, uniform dispersion of BNNTs, followed by N,N-dimethylformamide (DMF), acetone, and N-methyl-2-pyrrolidone (NMP). Utilizing the known Hansen solubility parameters of these solvents in comparison to the BNNT dispersion state, a region of good solubility was proposed. This solubility region was used to identify co-solvent systems that led to improved BNNT dispersion in poor solvents such as toluene, hexane, and ethanol. Incorporating the data from the co-solvent studies further refined the proposed solubility region. From this region, the Hansen solubility parameters for BNNTs are thought to lie at the midpoint of the solubility sphere: 16.8, 10.7, and 9.0 MPa(1/2) for δd, δp, and δh, respectively, with a calculated Hildebrand parameter of 21.8 MPa(1/2).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Xuchu; Hu, Mary Y.; Wei, Xiaoliang

Understanding the solvation structures of electrolytes should prove conducive for the development of nonaqueous redox flow batteries that hold considerable potential for future large scale energy storage systems. The utilization of an emerging ionic-derivatived ferrocene compound, ferrocenylmethyl dimethyl ethyl ammonium bis(trifluoromethanesulfonyl)imide (Fc1N112-TFSI), has recently overcome the issue of solubility in the supporting electrolyte. In this work, 13C, 1H and 17O NMR investigations were carried out using electrolyte solutions consisting of Fc1N112-TFSI as the solute and the mixed alkyl carbonate as the solvent. It was observed that the spectra of 13C experience changes of chemical shifts while those of 17O undergomore » linewidth broadening, indicating interactions between solute and solvent molecules. Quantum chemistry calculations of both molecular structures and chemical shifts (13C, 1H and 17O) are performed for interpreting experimental results and of understanding the detailed solvation structures and molecular dynamics. The results indicate that Fc1N112-TFSI is dissociated at varying degrees in mixed solvent depending on concentrations. Solvent molecules encircle Fc1N112 and TFSI respectively as solvation shells, rapidly exchanging with both bulk solvent and TFSI. Additionally, the solvent with high dielectric constant is more capable of dissociating Fc1N112-TFSI molecules compared with those with low dielectric constant. At saturated concentration, contact ion pairs are formed and the solvent molecules are interacting with the Fc rings rather than interacting with the ionic pendant arm of Fc1N112-TFSI. These studies will contribute to the development of nonaqueous electrolytes of storage systems.« less

The reorganization energy of electron transfer in nonpolar solvents: Molecular level treatment of the solvent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leontyev, I.V.; Tachiya, M.

The intermolecular electron transfer in a solute pair consisting of pyrene and dimethylaniline is investigated in a nonpolar solvent, n-hexane. The earlier elaborated approach [M. Tachiya, J. Phys Chem. 97, 5911 (1993)] is used; this method provides a physically relevant background for separating inertial and inertialess polarization responses for both nonpolarizable and polarizable molecular level simulations. The molecular-dynamics technique was implemented for obtaining the equilibrium ensemble of solvent configurations. The nonpolar solvent, n-hexane, was treated in terms of OPLS-AA parametrization. Solute Lennard-Jones parameters were taken from the same parametrization. Solute charge distributions of the initial and final states were determinedmore » using ab initio level [HF/6-31G(d,p)] quantum-chemical calculations. Configuration analysis was performed explicitly taking into account the anisotropic polarizability of n-hexane. It is shown that the Gaussian law well describes calculated distribution functions of the solvent coordinate, therefore, the rate constant of the ET reaction can be characterized by the reorganization energy. Evaluated values of the reorganization energies are in a range of 0.03-0.11 eV and significant contribution (more then 40% of magnitude) comes from anisotropic polarizability. Investigation of the reorganization energy {lambda} dependence on the solute pair separation distance d revealed unexpected behavior. The dependence has a very sharp peak at the distance d=7 A where solvent molecules are able to penetrate into the intermediate space between the solute pair. The reason for such behavior is clarified. This new effect has a purely molecular origin and cannot be described within conventional continuum solvent models.« less

Put the lid on VOC emissions from maintenance coatings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, R.E.

1996-11-01

After the coating film is applied to the substrate, the solvents evaporate and generally become an environmental liability. Solvents used by the coatings industry have been a major environmental issue for many years. Over the years, regulations have been aimed at reducing or eliminating photochemically reactive solvents--those that react in the atmosphere with nitrogen oxides in the atmosphere with nitrogen oxides in the presence of sunlight and heat to form ozones. Many of the solvents used in the coatings industry are, in fact, photochemically reactive. The rules regulating the maintenance coatings industry can generally be divided into three categories: 1.more » Rules aimed at restricting the VOCs in steel fabricating shops and paint shops. 2. Rules aimed at regulating the emission of VOCs from coatings applied in the field such as on bridges or industrial structures. 3. Rules aimed at the shipbuilding industry where coatings are applied to marine vessels. The paper discusses reducing VOCs, penetrating sealers, mastics, tank linings, inorganic zincs, topcoats--waterborne acrylics, zero-VOC urethane/water systems, and solventless topcoats.« less

Electropolymerized carbonic anhydrase immobilization for carbon dioxide capture.

PubMed

Merle, Geraldine; Fradette, Sylvie; Madore, Eric; Barralet, Jake E

2014-06-17

Biomimetic carbonation carried out with carbonic anhydrase (CA) in CO2-absorbing solutions, such as methyldiethanolamine (MDEA), is one approach that has been developed to accelerate the capture of CO2. However, there are several practical issues, such as high cost and limited enzyme stability, that need to be overcome. In this study, the capacity of CA immobilization on a porous solid support was studied to improve the instability in the tertiary amine solvent. We have shown that a 63% porosity macroporous carbon foam support makes separation and reuse facile and allows for an efficient supply and presentation of CO2 to an aqueous solvent and the enzyme catalytic center. These enzymatic supports conserved 40% of their initial activity after 42 days at 70 °C in an amine solvent, whereas the free enzyme shows no activity after 1 h in the same conditions. In this work, we have overcome the technical barrier associated with the recovery of the biocatalyst after operation, and most of all, these electropolymerized enzymatic supports have shown a remarkable increase of thermal stability in an amine-based CO2 sequestration solvent.

Clinical roundtable monograph: Recent advances in taxanes for the first-line treatment of advanced non-small cell lung cancer.

PubMed

Socinski, Mark A; Govindan, Ramaswamy; Spigel, David

2012-10-01

Treatments for non-small cell lung cancer (NSCLC) are based on the broad categories of squamous or non-squamous histology. Frontline treatment options include pemetrexed and cisplatin, pemetrexed and a taxane, gemcitabine with cisplatin, and the addition of bevacizumab to a taxane and carboplatin. Pemetrexed is used for maintenance therapy for non-squamous NSCLC, whereas patients with squamous NSCLC lack easy options for maintenance therapy. nab-Paclitaxel overcomes the solubility and toxicity issues of solvent-based paclitaxel, and the albumin in nab-paclitaxel improves the concentration of the drug in the tumor. A recent phase III trial in NSCLC compared nab-paclitaxel with carboplatin versus solvent-based paclitaxel with carboplatin, and found improved overall response rates (ORRs) in the nab-paclitaxel arm (33% vs 25%; P=.005). In a subset analysis, NSCLC patients with squamous histology had a higher ORR (41%) with nab-paclitaxel than with solvent-based paclitaxel (24%; P<.001). Another subset analysis found that patients ages 70 years and older had improved overall survival (median 19.9 months) with nab-paclitaxel compared with solvent-based paclitaxel (median 10.4 months; P=.009). Patients in the nab-paclitaxel arm had less neuropathy, less hearing loss, and fewer interruptions in daily living than patients in the solvent-based paclitaxel arm.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Shenggao, E-mail: sgzhou@suda.edu.cn, E-mail: bli@math.ucsd.edu; Sun, Hui; Cheng, Li-Tien

Recent years have seen the initial success of a variational implicit-solvent model (VISM), implemented with a robust level-set method, in capturing efficiently different hydration states and providing quantitatively good estimation of solvation free energies of biomolecules. The level-set minimization of the VISM solvation free-energy functional of all possible solute-solvent interfaces or dielectric boundaries predicts an equilibrium biomolecular conformation that is often close to an initial guess. In this work, we develop a theory in the form of Langevin geometrical flow to incorporate solute-solvent interfacial fluctuations into the VISM. Such fluctuations are crucial to biomolecular conformational changes and binding process. Wemore » also develop a stochastic level-set method to numerically implement such a theory. We describe the interfacial fluctuation through the “normal velocity” that is the solute-solvent interfacial force, derive the corresponding stochastic level-set equation in the sense of Stratonovich so that the surface representation is independent of the choice of implicit function, and develop numerical techniques for solving such an equation and processing the numerical data. We apply our computational method to study the dewetting transition in the system of two hydrophobic plates and a hydrophobic cavity of a synthetic host molecule cucurbit[7]uril. Numerical simulations demonstrate that our approach can describe an underlying system jumping out of a local minimum of the free-energy functional and can capture dewetting transitions of hydrophobic systems. In the case of two hydrophobic plates, we find that the wavelength of interfacial fluctuations has a strong influence to the dewetting transition. In addition, we find that the estimated energy barrier of the dewetting transition scales quadratically with the inter-plate distance, agreeing well with existing studies of molecular dynamics simulations. Our work is a first step toward the inclusion of fluctuations into the VISM and understanding the impact of interfacial fluctuations on biomolecular solvation with an implicit-solvent approach.« less

Waste Minimization Study on Pyrochemical Reprocessing Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boussier, H.; Conocar, O.; Lacquement, J.

2006-07-01

Ideally a new pyro-process should not generate more waste, and should be at least as safe and cost effective as the hydrometallurgical processes currently implemented at industrial scale. This paper describes the thought process, the methodology and some results obtained by process integration studies to devise potential pyro-processes and to assess their capability of achieving this challenging objective. As example the assessment of a process based on salt/metal reductive extraction, designed for the reprocessing of Generation IV carbide spent fuels, is developed. Salt/metal reductive extraction uses the capability of some metals, aluminum in this case, to selectively reduce actinide fluoridesmore » previously dissolved in a fluoride salt bath. The reduced actinides enter the metal phase from which they are subsequently recovered; the fission products remain in the salt phase. In fact, the process is not so simple, as it requires upstream and downstream subsidiary steps. All these process steps generate secondary waste flows representing sources of actinide leakage and/or FP discharge. In aqueous processes the main solvent (nitric acid solution) has a low boiling point and evaporate easily or can be removed by distillation, thereby leaving limited flow containing the dissolved substance behind to be incorporated in a confinement matrix. From the point of view of waste generation, one main handicap of molten salt processes, is that the saline phase (fluoride in our case) used as solvent is of same nature than the solutes (radionuclides fluorides) and has a quite high boiling point. So it is not so easy, than it is with aqueous solutions, to separate solvent and solutes in order to confine only radioactive material and limit the final waste flows. Starting from the initial block diagram devised two years ago, the paper shows how process integration studies were able to propose process fittings which lead to a reduction of the waste variety and flows leading at an 'ideal' new block diagram allowing internal solvent recycling, and self eliminating reactants. This new flowsheet minimizes the quantity of inactive inlet flows that would have inevitably to be incorporated in a final waste form. The study identifies all knowledge gaps to be filled and suggest some possible R and D issues to confirm or infirm the feasibility of the proposed process fittings. (authors)« less

Digital telephony analysis model and issues

NASA Astrophysics Data System (ADS)

Keuthan, Lynn M.

1995-09-01

Experts in the fields of digital telephony and communications security have stated the need for an analytical tool for evaluating complex issues. Some important policy issues discussed by experts recently include implementing digital wire-taps, implementation of the 'Clipper Chip', required registration of encryption/decryption keys, and export control of cryptographic equipment. Associated with the implementation of these policies are direct costs resulting from implementation, indirect cost benefits from implementation, and indirect costs resulting from the risks of implementation or factors reducing cost benefits. Presented herein is a model for analyzing digital telephony policies and systems and their associated direct costs and indirect benefit and risk factors. In order to present the structure of the model, issues of national importance and business-related issues are discussed. The various factors impacting the implementation of the associated communications systems and communications security are summarized, and various implementation tradeoffs are compared based on economic benefits/impact. The importance of the issues addressed herein, as well as other digital telephony issues, has greatly increased with the enormous increases in communication system connectivity due to the advance of the National Information Infrastructure.

Stable solvent for solution-based electrical doping of semiconducting polymer films and its application to organic solar cells

DOE PAGES

Larrain, Felipe A.; Fuentes-Hernandez, Canek; Chou, Wen-Fang; ...

2018-01-01

A solution-based method to electrically p-dope organic semiconductors enabling the fabrication of organic solar cells with simplified geometry is implemented with acetonitrile as an alternative to nitromethane.

Stable solvent for solution-based electrical doping of semiconducting polymer films and its application to organic solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larrain, Felipe A.; Fuentes-Hernandez, Canek; Chou, Wen-Fang

A solution-based method to electrically p-dope organic semiconductors enabling the fabrication of organic solar cells with simplified geometry is implemented with acetonitrile as an alternative to nitromethane.

EVALUATION OF SUPERCRITICAL CARBON DIOXIDE TECHNOLOGY TO REDUCE SOLVENT IN SPRAY COATING APPLICATIONS

EPA Science Inventory

This evaluation, part of the Pollution Prevention Clean Technology Demonstration (CTD) Program, addresses the product quality, waste reduction, and economic issues of spray paint application using supercritical carbon dioxide (CO2). Anion Carbide has developed this technology and...

Negative-tone development of photoresists in environmentally friendly silicone fluids

NASA Astrophysics Data System (ADS)

Ouyang, Christine Y.; Lee, Jin-Kyun; Ober, Christopher K.

2012-03-01

The large amount of organic solvents and chemicals that are used in today's microelectronic fabrication process can lead to environmental, health and safety hazards. It is therefore necessary to design new materials and new processes to reduce the environmental impact of the lithographic process. In addition, as the feature sizes decrease, other issues such as pattern collapse, which is related to the undesirable high surface tension of the developers and rinse liquids, can occur and limit the resolution. In order to solve these issues, silicone fluids are chosen as alternative developing solvents in this paper. Silicone fluids, also known as linear methyl siloxanes, are a class of mild, non-polar solvents that are non-toxic, not ozone-depleting, and contribute little to global warming. They are considered as promising developers because of their environmental-friendliness and their unique physical properties such as low viscosity and low surface tension. Recently, there have been emerging interests in negative-tone development (NTD) due to its better ability in printing contact holes and trenches. It is also found that the performance of negative-tone development is closely related to the developing solvents. Silicone fluids are thus promising developers for NTD because of their non-polar nature and high contrast negative-tone images are expected with chemical amplification photoresists due to the high chemical contrast of chemical amplification. We have previously shown some successful NTD with conventional photoresists such as ESCAP in silicone fluids. In this paper, another commercially available TOK resist was utilized to study the NTD process in silicone fluids. Because small and non-polar molecules are intrinsically soluble in silicone fluids, we have designed a molecular glass resist for silicone fluids. Due to the low surface tension of silicone fluids, we are able achieve high aspect-ratio, high-resolution patterns without pattern collapse.

Inkjet printing of 2D layered materials.

PubMed

Li, Jiantong; Lemme, Max C; Östling, Mikael

2014-11-10

Inkjet printing of 2D layered materials, such as graphene and MoS2, has attracted great interests for emerging electronics. However, incompatible rheology, low concentration, severe aggregation and toxicity of solvents constitute critical challenges which hamper the manufacturing efficiency and product quality. Here, we introduce a simple and general technology concept (distillation-assisted solvent exchange) to efficiently overcome these challenges. By implementing the concept, we have demonstrated excellent jetting performance, ideal printing patterns and a variety of promising applications for inkjet printing of 2D layered materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of 4H <000-1> Silicon Carbide Films Grown by Solvent-Laser Heated Floating Zone

NASA Technical Reports Server (NTRS)

Woodworth, Andrew, A; Sayir, Ali; Neudeck, Philip, G; Raghothamachar, Balaji; Dudley, Michael

2012-01-01

Commercially available bulk silicon carbide (SiC) has a high number (>2000/sq cm) of screw dislocations (SD) that have been linked to degradation of high-field power device electrical performance properties. Researchers at the NASA Glenn Research Center have proposed a method to mass-produce significantly higher quality bulk SiC. In order for this bulk growth method to become reality, growth of long single crystal SiC fibers must first be achieved. Therefore, a new growth method, Solvent-Laser Heated Floating Zone (Solvent-LHFZ), has been implemented. While some of the initial Solvent-LHFZ results have recently been reported, this paper focuses on further characterization of grown crystals and their growth fronts. To this end, secondary ion mass spectroscopy (SIMS) depth profiles, cross section analysis by focused ion beam (FIB) milling and mechanical polishing, and orientation and structural characterization by x-ray transmission Laue diffraction patterns and x-ray topography were used. Results paint a picture of a chaotic growth front, with Fe incorporation dependant on C concentration.

MICROBIAL CHARACTERIZATION OF MANURE BASED PERMEABLE REACTIVE BARRIER

EPA Science Inventory

The implementation of permeable reactive barriers (PRB) provides a viable option for the remediation of contaminants of environmental significance such as dissolved metals (i.e., chromium), chlorinated solvents, and nitrate/ammonia. The designs of PRBs are usually based on the a...

Effects of metals on the transformation of hexabromocyclododecane (HBCD) in solvents: implications for solvent-based recycling of brominated flame retardants.

PubMed

Zhong, Yin; Peng, Ping'an; Yu, Zhiqiang; Deng, Haopeng

2010-09-01

The management of electronic wastes (e-wastes) has become a global issue as it may release large quantities of hazardous materials such as heavy metals and brominated flame retardants (BFRs) to the environment. Solvent-based recycling is a newly developed, efficient and environmentally beneficial technology for the removal or recovery of BFRs from e-wastes. However, little is known about the behavior of BFRs in the solvents and to what extent they may be affected by co-existing heavy metals. This study quantified the rates of transformation of hexabromocyclododecane (HBCD), a widely used BFR, in the presence of different solvents (i.e. acetone, methanol or toluene) and metals (i.e. Ni, Cu, Zn, Fe or Al). Our experimental results showed that less than 20% of HBCD was transformed in all pure solvent systems within 24h at 50 degrees C. The presence of Ni greatly increased the transformation of HBCD (45-99%) in these solvent systems, whereas other metals had little or no effect on extraction process. The kinetics study showed that transformation of HBCD in Ni-containing systems followed pseudo-first-order kinetics and that the highest transformation rate constant (1.2+/-0.1h(-1)) of HBCD was recorded in the Ni+acetone system. The formation of HBr and pentabromocyclododecene in the acetone+Ni system suggested that transformation of HBCD proceeded via dehydrobromination. Collectively, these results indicated that acetone should not be applied in the recycling or extraction of HBCD from Ni-rich e-wastes, as debromination of HBCD may occur during these processes, even at mild extraction temperatures. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

A combined TD-DFT and spectroscopic investigation of the solute-solvent interactions of efavirenz

NASA Astrophysics Data System (ADS)

Jordaan, Maryam A.; Singh, Parvesh; Martincigh, Bice S.

2016-03-01

Efavirenz, commercially known as Sustiva® or Stocrin®, is a first-line antiretroviral treatment for HIV/AIDS. The clinical efficacy of efavirenz is, however, hindered by its solubility. We sought to investigate the solute-solvent effects of efavirenz by means of a combined qualitative study implementing UV-visible spectrophotometry, 1H NMR spectroscopy and time-dependent density functional theory (TD-DFT) calculations. The UV spectrum displayed two main absorbance maxima, band I and band II at 246-260 and 291-295 nm, respectively. A general bathochromic shift was noticed from the non-polar solvent cyclohexane to the most polar solvent DMSO (≈ 13.69 nm) in band I and a smaller bathochromic (≈ 2.17 nm) and hyperchromic shift was observed in band II. We propose that these observations are due to the role of the amino (NH) and carbonyl (CO) functionalities which induce charge-transfer and intra- and inter-molecular hydrogen bonding. The aromatic and amine protons showed the most deshielded effects in the observed chemical shifts (δ) in the more polar DMSO-d6 solvent relative to CDCl3. The 1H NMR chemical shifts observed are due to the increased delocalization of the lone pair electrons of the amino nitrogen with increased polarity of the more polar DMSO solvent. The theoretical reproduction of the UV and 1H NMR spectra by means of TD-DFT is in good agreement with the experimental results.

Accelerating Molecular Dynamic Simulation on Graphics Processing Units

PubMed Central

Friedrichs, Mark S.; Eastman, Peter; Vaidyanathan, Vishal; Houston, Mike; Legrand, Scott; Beberg, Adam L.; Ensign, Daniel L.; Bruns, Christopher M.; Pande, Vijay S.

2009-01-01

We describe a complete implementation of all-atom protein molecular dynamics running entirely on a graphics processing unit (GPU), including all standard force field terms, integration, constraints, and implicit solvent. We discuss the design of our algorithms and important optimizations needed to fully take advantage of a GPU. We evaluate its performance, and show that it can be more than 700 times faster than a conventional implementation running on a single CPU core. PMID:19191337

Wiltech Component Cleaning and Refurbishment Facility CFC Elimination Plan at NASA Kennedy Space Center

NASA Technical Reports Server (NTRS)

Williamson, Steve; Aman, Bob; Aurigema, Andrew; Melendez, Orlando

1999-01-01

The Wiltech Component Cleaning & Refurbishment Facility (WT-CCRF) at NASA Kennedy Space Center performs precision cleaning on approximately 200,000 metallic and non metallic components every year. WT-CCRF has developed a CFC elimination plan consisting of aqueous cleaning and verification and an economical dual solvent strategy for alternative solvent solution. Aqueous Verification Methodologies were implemented two years ago on a variety of Ground Support Equipment (GSE) components and sampling equipment. Today, 50% of the current workload is verified using aqueous methods and 90% of the total workload is degreased aqueously using, Zonyl and Brulin surfactants in ultrasonic baths. An additional estimated 20% solvent savings could be achieved if the proposed expanded use of aqueous methods are approved. Aqueous cleaning has shown to be effective, environmentally friendly and economical (i.e.. cost of materials, equipment, facilities and labor).

Mesoscopic electrohydrodynamic simulations of binary colloidal suspensions.

PubMed

Rivas, Nicolas; Frijters, Stefan; Pagonabarraga, Ignacio; Harting, Jens

2018-04-14

A model is presented for the solution of electrokinetic phenomena of colloidal suspensions in fluid mixtures. We solve the discrete Boltzmann equation with a Bhatnagar-Gross-Krook collision operator using the lattice Boltzmann method to simulate binary fluid flows. Solvent-solvent and solvent-solute interactions are implemented using a pseudopotential model. The Nernst-Planck equation, describing the kinetics of dissolved ion species, is solved using a finite difference discretization based on the link-flux method. The colloids are resolved on the lattice and coupled to the hydrodynamics and electrokinetics through appropriate boundary conditions. We present the first full integration of these three elements. The model is validated by comparing with known analytic solutions of ionic distributions at fluid interfaces, dielectric droplet deformations, and the electrophoretic mobility of colloidal suspensions. Its possibilities are explored by considering various physical systems, such as breakup of charged and neutral droplets and colloidal dynamics at either planar or spherical fluid interfaces.

Mesoscopic electrohydrodynamic simulations of binary colloidal suspensions

NASA Astrophysics Data System (ADS)

Rivas, Nicolas; Frijters, Stefan; Pagonabarraga, Ignacio; Harting, Jens

2018-04-01

A model is presented for the solution of electrokinetic phenomena of colloidal suspensions in fluid mixtures. We solve the discrete Boltzmann equation with a Bhatnagar-Gross-Krook collision operator using the lattice Boltzmann method to simulate binary fluid flows. Solvent-solvent and solvent-solute interactions are implemented using a pseudopotential model. The Nernst-Planck equation, describing the kinetics of dissolved ion species, is solved using a finite difference discretization based on the link-flux method. The colloids are resolved on the lattice and coupled to the hydrodynamics and electrokinetics through appropriate boundary conditions. We present the first full integration of these three elements. The model is validated by comparing with known analytic solutions of ionic distributions at fluid interfaces, dielectric droplet deformations, and the electrophoretic mobility of colloidal suspensions. Its possibilities are explored by considering various physical systems, such as breakup of charged and neutral droplets and colloidal dynamics at either planar or spherical fluid interfaces.

Organic Adsorption Capacity of Aluminum for Potential Mars Sample Return Contamination Analysis

NASA Astrophysics Data System (ADS)

Skoog, E. J.; Tuite, M. L., Jr.; Williford, K. H.

2017-12-01

The NASA Mars 2020 rover will sample martian rock and regolith as it searches for biosignatures and chemical potential for life. Possible contamination of martian samples by Earth-derived organic and inorganic materials poses a challenge to the ultimate goal of determining whether features detected within samples are of martian origin. To address this issue, Mars 2020 will implement a contamination knowledge strategy that includes "witness blanks": special sample tubes that contain multiple "getter" materials designed to witness any ambient contamination in the environment during sampling events on Mars. One getter material being considered for use inside witness tubes is aluminum foil. Here we present data from a series of experiments to evaluate the capacity of aluminum foil to adsorb organics and release them by solvent extraction. Strips of clean aluminum foil were suspended in closed vials containing 0.15 mg of pyrene and heated to 50°C to provide a bounding case for ambient pyrene concentration. Another set of foil strips in vials was stored at -20°C to better simulate martian conditions. After ten weeks, these foil strips were exposed to pyrene at additive 15 minute increments to test the time dependence of pyrene adsorption at -20°C. Foil strips were removed from vials and subjected to solvent extraction gas chromatography mass spectrometry. Preliminary results suggest that the pyrene adsorption capacity of aluminum at 50°C is 1-10 ng/cm2 after 24 hours. Further research will test the adsorption capacity of aluminum at varying temperatures, varying times, and varying organic compositions.

LONG TERM PERFORMANCE MONITORING OF A PRB FOR REMEDIATION OF CHLORINATED SOLVENTS AND CHROMIUM

EPA Science Inventory

Permeable reactive barriers (PRB's) are an emerging, alternative in-situ approach for remediating groundwater contamination that combine subsurface fluid flow management with a passive chemical treatment zone. The few pilot and commercial installations which have been implemented...

Analysis of non-phthalates plasticizers on porous graphitic carbon by supercritical fluid chromatography using evaporative light scattering detection.

PubMed

Vaccher, Claude; Decaudin, Bertrand; Sautou, Valérie; Lecoeur, Marie

2014-09-12

The analysis of several plasticizers, widely used in the production of medical devices, was investigated on porous graphitic carbon (PGC) stationary phase in supercritical fluid chromatography (SFC) with an evaporative light scattering detector (ELSD). Due to strong interaction of compounds with the PGC support, solvents of strong eluotropic strength were added to the CO2 supercritical fluid. The effect of alkyl chain (pentane, hexane, heptane) and chlorinated (CH2Cl2, CHCl3, CCl4) solvents was studied on the retention and on the ELSD detection of plasticizers. A co-solvent mixture composed of CHCl3/heptane, eluted under gradient mode, allowed a significant improvement of the ELSD response compared to the use of each solvent individually. Then, a central composite design (CCD) was implemented to optimize both the separation and the detection of plasticizers. The parameters involved were the outlet pressure, the gradient slope, the co-solvent composition and the drift tube temperature of the ELSD. After optimization, baseline separation of plasticizers was achieved in 7min and best signal-to-noise ratios were obtained with outlet pressure and drift tube temperature of ELSD set at 200bar and 31°C, respectively. The co-solvent mixture was also composed of CHCl3/heptane (35/65 v/v) and a gradient from 15 to 60% of co-solvent in 2.2min was employed. The results demonstrated that CCD is a powerful tool for the optimization of SFC/ELSD method and the response surface model analysis can provide statistical understandings of the significant factors required to achieve optimal separation and ELSD sensitivity. Copyright © 2014 Elsevier B.V. All rights reserved.

Assigning exposure to pesticides and solvents from self-reports collected by a computer assisted personal interview and expert assessment of job codes: the UK Adult Brain Tumour Study.

PubMed

Hepworth, S J; Bolton, A; Parslow, R C; van Tongeren, M; Muir, K R; McKinney, P A

2006-04-01

To compare assignment of occupational pesticide and solvent exposure using self-reported data collected by a computer assisted personal interview (CAPI) with exposure based on expert assessment of job codes. To discuss the advantages and disadvantages of using a CAPI to collect individual occupational exposure data. Between 2001 and 2004, 1495 participants were interviewed using a CAPI for a case-control study of adult brain tumours and acoustic neuromas. Two types of occupational data were collected: (1) a full history, including job title from which a job code was assigned from the Standard Occupational Classification; and (2) specific details on pesticide and solvent exposure reported by participants. Study members' experiences of using the CAPI were recorded and advantages and disadvantages summarised. Of 7192 jobs recorded, the prevalence of self-reported exposure was 1.3% for pesticides and 11.5% for solvents. Comparing this with exposure expertly assessed from job titles showed 53.6% and 45.8% concordance for pesticides and solvents respectively. Advantages of the CAPI include no data entry stage, automatic input validation, and a reduction in interviewer bias. Disadvantages include an adverse effect on study implementation as a consequence of resources required for programming and difficulties encountered with data management prior to analysis. Different methods of exposure assessment derive different exposure levels for pesticide and solvent exposure at work. Agreement between self-reported and expert assessment of exposure was greater for pesticides compared to solvents. The advantages of using a CAPI for the collection of complex data outweigh the disadvantages for interviewers and data quality but using such a method requires extra resources at the study outset.

Assigning exposure to pesticides and solvents from self‐reports collected by a computer assisted personal interview and expert assessment of job codes: the UK Adult Brain Tumour Study

PubMed Central

Hepworth, S J; Bolton, A; Parslow, R C; van Tongeren, M; Muir, K R; McKinney, P A

2006-01-01

Objectives To compare assignment of occupational pesticide and solvent exposure using self‐reported data collected by a computer assisted personal interview (CAPI) with exposure based on expert assessment of job codes. To discuss the advantages and disadvantages of using a CAPI to collect individual occupational exposure data. Methods Between 2001 and 2004, 1495 participants were interviewed using a CAPI for a case‐control study of adult brain tumours and acoustic neuromas. Two types of occupational data were collected: (1) a full history, including job title from which a job code was assigned from the Standard Occupational Classification; and (2) specific details on pesticide and solvent exposure reported by participants. Study members' experiences of using the CAPI were recorded and advantages and disadvantages summarised. Results Of 7192 jobs recorded, the prevalence of self‐reported exposure was 1.3% for pesticides and 11.5% for solvents. Comparing this with exposure expertly assessed from job titles showed 53.6% and 45.8% concordance for pesticides and solvents respectively. Advantages of the CAPI include no data entry stage, automatic input validation, and a reduction in interviewer bias. Disadvantages include an adverse effect on study implementation as a consequence of resources required for programming and difficulties encountered with data management prior to analysis. Conclusions Different methods of exposure assessment derive different exposure levels for pesticide and solvent exposure at work. Agreement between self‐reported and expert assessment of exposure was greater for pesticides compared to solvents. The advantages of using a CAPI for the collection of complex data outweigh the disadvantages for interviewers and data quality but using such a method requires extra resources at the study outset. PMID:16556747

METHODOLOGICAL ISSUES IN HUMAN EXPOSURE STUDIES OF LOW LEVEL SOLVENT MIXTURES

EPA Science Inventory

The design of appropriate studies to assess the sensory irritant and neurobehavioral-effects of exposure to complex VOC mixtures poses a variety of methodological challenges, particularly at the low levels found in new buildings. or instance, Otto et al (1989) exposed subjects to...

Electron transfer in silicon-bridged adjacent chromophores: the source for blue-green emission.

PubMed

Bayda, Malgorzata; Angulo, Gonzalo; Hug, Gordon L; Ludwiczak, Monika; Karolczak, Jerzy; Koput, Jacek; Dobkowski, Jacek; Marciniak, Bronislaw

2017-05-10

Si-Bridged chromophores have been proposed as sources for blue-green emission in several technological applications. The origin of this dual emission is to be found in an internal charge transfer reaction. The current work is an attempt to describe the details of these processes in these kinds of substances, and to design a molecular architecture to improve their performance. Nuclear motions essential for intramolecular charge transfer (ICT) can involve processes from twisted internal moieties to dielectric relaxation of the solvent. To address these issues, we studied ICT between adjacent chromophores in a molecular compound containing N-isopropylcarbazole (CBL) and 1,4-divinylbenzene (DVB) linked by a dimethylsilylene bridge. In nonpolar solvents emission arises from the local excited state (LE) of carbazole whereas in solvents of higher polarity dual emission was detected (LE + ICT). The CT character of the additional emission band was concluded from the linear dependence of the fluorescence maxima on solvent polarity. Electron transfer from CBL to DVB resulted in a large excited-state dipole moment (37.3 D) as determined from a solvatochromic plot and DFT calculations. Steady-state and picosecond time-resolved fluorescence experiments in butyronitrile (293-173 K) showed that the ICT excited state arises from the LE state of carbazole. These results were analyzed and found to be in accordance with an adiabatic version of Marcus theory including solvent relaxation.

Separation of switchgrass bio-oil by water/organic solvent addition and pH adjustment

DOE PAGES

Park, Lydia Kyoung-Eun; Ren, Shoujie; Yiacoumi, Sotira; ...

2016-01-29

Applications of bio-oil are limited by its challenging properties including high moisture content, low pH, high viscosity, high oxygen content, and low heating value. Separation of switchgrass bio-oil components by adding water, organic solvents (hexadecane and octane), and sodium hydroxide may help to overcome these issues. Acetic acid and phenolic compounds were extracted in aqueous and organic phases, respectively. Polar chemicals, such as acetic acid, did not partition in the organic solvent phase. Acetic acid in the aqueous phase after extraction is beneficial for a microbial-electrolysis-cell application to produce hydrogen as an energy source for further hydrodeoxygenation of bio-oil. Organicmore » solvents extracted more chemicals from bio-oil in combined than in sequential extraction; however, organic solvents partitioned into the aqueous phase in combined extraction. When sodium hydroxide was added to adjust the pH of aqueous bio-oil, organic-phase precipitation occurred. As the pH was increased, a biphasic aqueous/organic dispersion was formed, and phase separation was optimized at approximately pH 6. The neutralized organic bio-oil had approximately 37% less oxygen and 100% increased heating value than the initial centrifuged bio-oil. In conclusion, the less oxygen content and increased heating value indicated a significant improvement of the bio-oil quality through neutralization.« less

Separation of switchgrass bio-oil by water/organic solvent addition and pH adjustment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Lydia Kyoung-Eun; Ren, Shoujie; Yiacoumi, Sotira

Applications of bio-oil are limited by its challenging properties including high moisture content, low pH, high viscosity, high oxygen content, and low heating value. Separation of switchgrass bio-oil components by adding water, organic solvents (hexadecane and octane), and sodium hydroxide may help to overcome these issues. Acetic acid and phenolic compounds were extracted in aqueous and organic phases, respectively. Polar chemicals, such as acetic acid, did not partition in the organic solvent phase. Acetic acid in the aqueous phase after extraction is beneficial for a microbial-electrolysis-cell application to produce hydrogen as an energy source for further hydrodeoxygenation of bio-oil. Organicmore » solvents extracted more chemicals from bio-oil in combined than in sequential extraction; however, organic solvents partitioned into the aqueous phase in combined extraction. When sodium hydroxide was added to adjust the pH of aqueous bio-oil, organic-phase precipitation occurred. As the pH was increased, a biphasic aqueous/organic dispersion was formed, and phase separation was optimized at approximately pH 6. The neutralized organic bio-oil had approximately 37% less oxygen and 100% increased heating value than the initial centrifuged bio-oil. In conclusion, the less oxygen content and increased heating value indicated a significant improvement of the bio-oil quality through neutralization.« less

Integrating a post-column makeup pump into preparative supercritical fluid chromatography systems to address stability and recovery issues during purifications.

PubMed

Bajpai, Lakshmikant; Naidu, Harshavardhan; Asokan, Kathiravan; Shaik, Khaja Mohiddin; Kaspady, Mahammed; Arunachalam, Piramanayagam; Wu, Dauh-Rurng; Mathur, Arvind; Sarabu, Ramakanth

2017-08-18

Purification of many pharmaceutical compounds by supercritical fluid chromatography (SFC) has always been challenging because of degradation of compound during the isolation step in the presence of acidic or basic modifiers in the mobile phase. Stability of such acid or base-sensitive compounds could be improved by post-column addition of a solvent containing base or acid modifier as counter ion through a make-up pump respectively to neutralize the compound fraction without affecting the resolution. One such case study has been presented in this work where the stability of a base-sensitive compound was addressed by the addition of acidic co-solvent through the make-up pump. Details of this setup and the investigation of degradation of the in-house base-sensitive compound are discussed in this paper. In addition, poor retentivity and low recovery of many non-polar compounds in SFC eluting under low co-solvent percentage is another major concern. Even though the desired separation could be achieved with low percentage of co-solvent, it's difficult to get the proper recovery after purification due to precipitation of the sample and significant aerosol formation inside the cyclone. We have demonstrated the first-time use of a post-column make-up pump on SFC 350 system to introduce additional solvent prior to cyclone to avoid the precipitation, reduce the aerosol formation and thus improve the recovery of non-polar compounds eluting under less than 10% of co-solvent. Copyright © 2017 Elsevier B.V. All rights reserved.

40 CFR 469.18 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2010 CFR

2010-07-01

... (PSNS). 469.18 Section 469.18 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ELECTRICAL AND ELECTRONIC COMPONENTS POINT SOURCE CATEGORY Semiconductor... monitoring pursuant to § 469.13 (c) and (d) of this regulation must implement the solvent management plan...

Explicitly Representing the Solvation Shell in Continuum Solvent Calculations

PubMed Central

Svendsen, Hallvard F.; Merz, Kenneth M.

2009-01-01

A method is presented to explicitly represent the first solvation shell in continuum solvation calculations. Initial solvation shell geometries were generated with classical molecular dynamics simulations. Clusters consisting of solute and 5 solvent molecules were fully relaxed in quantum mechanical calculations. The free energy of solvation of the solute was calculated from the free energy of formation of the cluster and the solvation free energy of the cluster calculated with continuum solvation models. The method has been implemented with two continuum solvation models, a Poisson-Boltzmann model and the IEF-PCM model. Calculations were carried out for a set of 60 ionic species. Implemented with the Poisson-Boltzmann model the method gave an unsigned average error of 2.1 kcal/mol and a RMSD of 2.6 kcal/mol for anions, for cations the unsigned average error was 2.8 kcal/mol and the RMSD 3.9 kcal/mol. Similar results were obtained with the IEF-PCM model. PMID:19425558

van der Waals Interactions on the Mesoscale: Open-Science Implementation, Anisotropy, Retardation, and Solvent Effects.

PubMed

Dryden, Daniel M; Hopkins, Jaime C; Denoyer, Lin K; Poudel, Lokendra; Steinmetz, Nicole F; Ching, Wai-Yim; Podgornik, Rudolf; Parsegian, Adrian; French, Roger H

2015-09-22

The self-assembly of heterogeneous mesoscale systems is mediated by long-range interactions, including van der Waals forces. Diverse mesoscale architectures, built of optically and morphologically anisotropic elements such as DNA, collagen, single-walled carbon nanotubes, and inorganic materials, require a tool to calculate the forces, torques, interaction energies, and Hamaker coefficients that govern assembly in such systems. The mesoscale Lifshitz theory of van der Waals interactions can accurately describe solvent and temperature effects, retardation, and optically and morphologically anisotropic materials for cylindrical and planar interaction geometries. The Gecko Hamaker open-science software implementation of this theory enables new and sophisticated insights into the properties of important organic/inorganic systems: interactions show an extended range of magnitudes and retardation rates, DNA interactions show an imprint of base pair composition, certain SWCNT interactions display retardation-dependent nonmonotonicity, and interactions are mapped across a range of material systems in order to facilitate rational mesoscale design.

Solvent-Free Synthesis of Zeolites: Mechanism and Utility.

PubMed

Wu, Qinming; Meng, Xiangju; Gao, Xionghou; Xiao, Feng-Shou

2018-05-08

Zeolites have been extensively studied for years in different areas of chemical industry, such as shape selective catalysis, ion-exchange, and gas adsorption and separation. Generally, zeolites are prepared from solvothermal synthesis in the presence of a large amounts of solvents such as water and alcohols in sealed autoclaves under autogenous pressure. Water has been regarded as essential to synthesize zeolites for fast mass transfer of reactants, but it occupies a large space in autoclaves, which greatly reduces the yield of zeolite products. Furthermore, polluted wastes and relatively high pressure due to the presence of water solvent in the synthesis also leads to environmental and safety issues. Recently, inspired by great benefits of solvent-free synthesis, including the environmental concerns, energy consumption, safety, and economic cost, researchers continually challenge the rationale of the solvent and reconsider the age-old question "Do we actually need solvents at all in zeolite synthesis?" In this Account, we briefly summarize our efforts to rationally synthesize zeolites via a solvent-free route. Our research demonstrates that a series of silica, aluminosilicate, and aluminophosphate-based zeolites can be successfully prepared by mixing, grinding, and heating starting solid materials under solvent-free conditions. Combining an organotemplate-free synthesis with a solvent-free approach maximizes the advantages resulting in a more sustainable synthetic route, which avoids using toxic and costly organic templates and the formation of harmful gases by calcination of organic templates at high temperature. Furthermore, new insights into the solvent-free crystallization process of zeolites have been provided by modern techniques such as NMR and UV-Raman spectroscopy, which should be helpful in designing new zeolite structures and developing novel routes for synthesis of zeolites. The role of water and the vital intermediates during the crystallization of zeolites have been proposed and verified. In addition to a significant reduction in liquid wastes and a remarkable increase in zeolite yields, the solvent-free synthesis of zeolites exhibits more unprecedented benefits, including (i) the formation of hierarchical micro-, meso-, and macrostructures, which benefit the mass transfer in the reactions, (ii) rapid synthesis at higher temperatures, which greatly improve the space-time yields of zeolites, and (iii) construction of a novel catalytic system for encapsulation of metal nanoparticles and metal oxide particles within zeolite crystals synergistically combining the advantages of catalytic metal nanoparticles and metal oxide particles (high activity) and zeolites (shape selectivity). We believe that the concept of "solvent-free synthesis of zeolites" would open a door for deep understanding of zeolite crystallization and the design of efficient zeolitic catalysts.

Ground Water Issue Paper: Synthesis Report on State of Understanding of Chlorinated Solvent Transformation

EPA Science Inventory

The U.S. EPA (1999) provided clarification of its policy on the application of MNA as a remedy for contaminated sites, and defines this alternative as “the reliance on natural attenuation processes (within the context of a carefully controlled and monitored site cleanup approach)...

Sub-slab vs. Near-slab Soil Vapor Profiles at a Chlorinated Solvent Site (1)

EPA Science Inventory

A critical issue in assessing the vapor intrusion pathway is the distribution and migration of VOCs from the subsurface source to the near surface environment. Of particular importance is the influence of a slab. Therefore, EPA/ORD is funding a research program with the primary...

Sub-slab vs. Near-slab Soil Vapor Profiles at a Chlorinated Solvent Site

EPA Science Inventory

A critical issue in assessing the vapor intrusion pathway is the distribution and migration of VOCs from the subsurface source to the near surface environment. Therefore, EPA/ORD funded a research project with the primary goal of comparing vertical profiles of soil gas concentrat...

PRELIMINARY EVALUATION OF DWPF IMPACTS OF BORIC ACID USE IN CESIUM STRIP FOR SWPF AND MCU

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M.

2010-09-28

A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the current dilute nitric acid strip solution with boric acid. To support this effort, the impact of using 0.01M, 0.1M, 0.25M and 0.5M boric acid in place of 0.001M nitric acid was evaluated for impacts on the DWPF facility. The evaluation only covered the impacts of boric acid in the strip effluent and does not address the other changes in solvents (i.e., the new extractant, called MaxCalix,more » or the new suppressor, guanidine). Boric acid additions may lead to increased hydrogen generation during the SRAT and SME cycles as well as change the rheological properties of the feed. The boron in the strip effluent will impact glass composition and could require each SME batch to be trimmed with boric acid to account for any changes in the boron from strip effluent additions. Addition of boron with the strip effluent will require changes in the frit composition and could lead to changes in melt behavior. The severity of the impacts from the boric acid additions is dependent on the amount of boric acid added by the strip effluent. The use of 0.1M or higher concentrations of boric acid in the strip effluent was found to significantly impact DWPF operations while the impact of 0.01M boric acid is expected to be relatively minor. Experimental testing is required to resolve the issues identified during the preliminary evaluation. The issues to be addressed by the testing are: (1) Impact on SRAT acid addition and hydrogen generation; (2) Impact on melter feed rheology; (3) Impact on glass composition control; (4) Impact on frit production; and (5) Impact on melter offgas. A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the current dilute nitric acid strip solution with boric acid. To support this effort, the impact of using 0.01M, 0.1M, 0.25M and 0.5M boric acid in place of 0.001M nitric acid was evaluated for impacts on the DWPF facility. The evaluation only covered the impacts of boric acid in the strip effluent and does not address the other changes in solvents (i.e., the new extractant, called MaxCalix, or the new suppressor, guanidine). Experimental testing with the improved solvent is required to determine the impact of any changes in the entrained solvent on DWPF processing.« less

FINAL REPORT: Room Temperature Hydrogen Storage in Nano-Confined Liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

VAJO, JOHN

2014-06-12

DOE continues to seek solid-state hydrogen storage materials with hydrogen densities of ≥6 wt% and ≥50 g/L that can deliver hydrogen and be recharged at room temperature and moderate pressures enabling widespread use in transportation applications. Meanwhile, development including vehicle engineering and delivery infrastructure continues for compressed-gas hydrogen storage systems. Although compressed gas storage avoids the materials-based issues associated with solid-state storage, achieving acceptable volumetric densities has been a persistent challenge. This project examined the possibility of developing storage materials that would be compatible with compressed gas storage technology based on enhanced hydrogen solubility in nano-confined liquid solvents. These materialsmore » would store hydrogen in molecular form eliminating many limitations of current solid-state materials while increasing the volumetric capacity of compressed hydrogen storage vessels. Experimental methods were developed to study hydrogen solubility in nano-confined liquids. These methods included 1) fabrication of composites comprised of volatile liquid solvents for hydrogen confined within the nano-sized pore volume of nanoporous scaffolds and 2) measuring the hydrogen uptake capacity of these composites without altering the composite composition. The hydrogen storage capacities of these nano-confined solvent/scaffold composites were compared with bulk solvents and with empty scaffolds. The solvents and scaffolds were varied to optimize the enhancement in hydrogen solubility that accompanies confinement of the solvent. In addition, computational simulations were performed to study the molecular-scale structure of liquid solvent when confined within an atomically realistic nano-sized pore of a model scaffold. Confined solvent was compared with similar simulations of bulk solvent. The results from the simulations were used to formulate a mechanism for the enhanced solubility and to guide the experiments. Overall, the combined experimental measurements and simulations indicate that hydrogen storage based on enhanced solubility in nano-confined liquids is unlikely to meet the storage densities required for practical use. Only low gravimetric capacities of < 0.5 wt% were achieved. More importantly, solvent filled scaffolds had lower volumetric capacities than corresponding empty scaffolds. Nevertheless, several of the composites measured did show significant (>~ 5x) enhanced hydrogen solubility relative to bulk solvent solubility, when the hydrogen capacity was attributed only to dissolution in the confined solvent. However, when the hydrogen capacity was compared to an empty scaffold that is known to store hydrogen by surface adsorption on the scaffold walls, including the solvent always reduced the hydrogen capacity. For the best composites, this reduction relative to an empty scaffold was ~30%; for the worst it was ~90%. The highest capacities were obtained with the largest solvent molecules and with scaffolds containing 3- dimensionally confined pore geometries. The simulations suggested that the capacity of the composites originated from hydrogen adsorption on the scaffold pore walls at sites not occupied by solvent molecules. Although liquid solvent filled the pores, not all of the adsorption sites on the pore walls were occupied due to restricted motion of the solvent molecules within the confined pore space.« less

A track process for solvent annealing of high-χ BCPs

NASA Astrophysics Data System (ADS)

Guerrero, Douglas J.; Sakavuyi, Kaumba; Xu, Kui; Gharbi, Ahmed; Tiron, Raluca; Servin, Isabelle; Pain, Laurent; Claveau, Guillaume; Stokes, Harold; Harumoto, Masahiko; Nicolet, Célia; Chevalier, Xavier

2017-03-01

High chi organic lamellar-forming block copolymers were prepared with 18 nm intrinsic period Lo value. The BCPs were coated on a neutral layer on silicon substrates and were either thermally annealed or exposed to solvent vapors both in a 300mm track. The effect of lowering the glass transition temperature (Tg) on the high chi BCP was investigated. Process temperatures and times were varied. It was found that the BCP having lower Tg exhibits faster kinetics and is able to reach alignment in a shorter time than a similar BCP having higher Tg. Fingerprint defect analysis also shows that the BCP with lower Tg has lower defects. The results show that fingerprint formation can be achieved with either ether or ester type solvents depending on the BCP used. The results show that a track process for solvent annealing of high-χ BCPs is feasible and could provide the path forward for incorporation of BCP in future nodes. Finally, directed self-assembly was demonstrated by implemented high chi polymers on a graphoepitaxy test vehicles. CD and line width roughness was evaluated on patterns with a multiplication factor up to 7.

Depletion force between two large spheres suspended in a bath of small spheres: onset of the Derjaguin limit.

PubMed

Oettel, M

2004-04-01

We analyze the depletion interaction between two hard colloids in a hard-sphere solvent and pay special attention to the limit of large size ratio between colloids and solvent particles which is governed by the well-known Derjaguin approximation. For separations between the colloids of less than the diameter of the solvent particles (defining the depletion region), the solvent structure between the colloids can be analyzed in terms of an effective two-dimensional gas. Thereby we find that the Derjaguin limit is approached more slowly than previously thought. This analysis is in good agreement with simulation data which are available for a moderate size ratio of 10. Small discrepancies in results from density functional theory (DFT) at this size ratio become amplified for larger size ratios. Therefore we have improved upon previous DFT techniques by imposing test-particle consistency which connects DFT to integral equations. However, the improved results show no convergence towards the Derjaguin limit and thus we conclude that this implementation of DFT together with previous ones which rely on test-particle insertion become unreliable in predicting the force in the depletion region for size ratios larger than 10.

First-principles study of solvent-solute mixed dumbbells in body-centered-cubic tungsten crystals

NASA Astrophysics Data System (ADS)

Suzudo, Tomoaki; Tsuru, Tomohito; Hasegawa, Akira

2018-07-01

Tungsten (W) is considered as a promising candidate for plasma-facing materials for future nuclear fusion devices, and selecting optimal alloying constituents is a critical issue to improve radiation resistance of the W alloys as well as to improve their mechanical properties. We conducted in the current study a series of first-principles calculations for investigating solvent-solute mixed dumbbells in W crystals. The results suggested that titanium (Ti), vanadium (V), and chromium (Cr) are favorable as solutes for W alloys from irradiation-effect perspectives because these elements are expected to promote vacancy-interstitial recombination without causing radiation-induced precipitation that reduces ductility of irradiated materials.

Electrostatic Hazard Considerations for ODC Solvent Replacement Selection Testing

NASA Technical Reports Server (NTRS)

Fairbourn, Brad

1999-01-01

ODC solvents are used to clean many critical substrates during solid rocket motor production operations. Electrostatic charge generation incidental to these cleaning operations can pose a major safety issue. Therefore, while determining the acceptability of various ODC replacement cleaners, one aspect of the selection criteria included determining the extent of electric charge generation during a typical solvent cleaning operation. A total of six candidate replacement cleaners, sixteen critical substrates, and two types of cleaning swatch materials were studied in simulated cleaning operations. Charge generation and accumulation effects were investigated by measuring the peak voltage and brush discharging effects associated with each cleaning process combination. In some cases, charge generation was found to be very severe. Using the conductivity information for each cleaner, the peak voltage data could in some cases, be qualitatively predicted. Test results indicated that severe charging effects could result in brush discharges that could potentially result in flash fire hazards when occurring in close proximity to flammable vapor/air mixtures. Process controls to effectively mitigate these hazards are discussed.

Conventional and dense gas techniques for the production of liposomes: a review.

PubMed

Meure, Louise A; Foster, Neil R; Dehghani, Fariba

2008-01-01

The aim of this review paper is to compare the potential of various techniques developed for production of homogenous, stable liposomes. Traditional techniques, such as Bangham, detergent depletion, ether/ethanol injection, reverse-phase evaporation and emulsion methods, were compared with the recent advanced techniques developed for liposome formation. The major hurdles for scaling up the traditional methods are the consumption of large quantities of volatile organic solvent, the stability and homogeneity of the liposomal product, as well as the lengthy multiple steps involved. The new methods have been designed to alleviate the current issues for liposome formulation. Dense gas liposome techniques are still in their infancy, however they have remarkable advantages in reducing the use of organic solvents, providing fast, single-stage production and producing stable, uniform liposomes. Techniques such as the membrane contactor and heating methods are also promising as they eliminate the use of organic solvent, however high temperature is still required for processing.

Instrumentation issues in implementation science.

PubMed

Martinez, Ruben G; Lewis, Cara C; Weiner, Bryan J

2014-09-04

Like many new fields, implementation science has become vulnerable to instrumentation issues that potentially threaten the strength of the developing knowledge base. For instance, many implementation studies report findings based on instruments that do not have established psychometric properties. This article aims to review six pressing instrumentation issues, discuss the impact of these issues on the field, and provide practical recommendations. This debate centers on the impact of the following instrumentation issues: use of frameworks, theories, and models; role of psychometric properties; use of 'home-grown' and adapted instruments; choosing the most appropriate evaluation method and approach; practicality; and need for decision-making tools. Practical recommendations include: use of consensus definitions for key implementation constructs; reporting standards (e.g., regarding psychometrics, instrument adaptation); when to use multiple forms of observation and mixed methods; and accessing instrument repositories and decision aid tools. This debate provides an overview of six key instrumentation issues and offers several courses of action to limit the impact of these issues on the field. With careful attention to these issues, the field of implementation science can potentially move forward at the rapid pace that is respectfully demanded by community stakeholders.

In and across bureaucracy: structural and administrative issues for the tobacco endgame.

PubMed

Isett, Kimberley R

2013-05-01

This article assesses the structural choices for the proposed tobacco endgame strategies. I focus on the issues associated with particular structural choices for the location of the implementation. Specifically, I discuss issues related to implementation of the endgame within a specific single agency, and issues related to a more widespread, broad implementation involving several agencies. Where appropriate, I provide examples of how the dynamics discussed would apply to particular endgame strategies. Issues related to design, administration, authority and finances are raised.

In and across bureaucracy: structural and administrative issues for the tobacco endgame

PubMed Central

Isett, Kimberley R

2013-01-01

This article assesses the structural choices for the proposed tobacco endgame strategies. I focus on the issues associated with particular structural choices for the location of the implementation. Specifically, I discuss issues related to implementation of the endgame within a specific single agency, and issues related to a more widespread, broad implementation involving several agencies. Where appropriate, I provide examples of how the dynamics discussed would apply to particular endgame strategies. Issues related to design, administration, authority and finances are raised. PMID:23591514

Broadband Light Collection Efficiency Enhancement of Carbon Nanotube Excitons Coupled to Metallo-Dielectric Antenna Arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shayan, Kamran; Rabut, Claire; Kong, Xiaoqing

The realization of on-chip quantum networks ideally requires lossless interfaces between photons and solid-state quantum emitters. We propose and demonstrate on-chip arrays of metallo-dielectric antennas (MDA) that are tailored toward efficient and broadband light collection from individual embedded carbon nanotube quantum emitters by trapping air gaps on chip that form cavity modes. Scalable implementation is realized by employing polymer layer dry-transfer techniques that avoid solvent incompatibility issues, as well as a planar design that avoids solid-immersion lenses. Cryogenic measurements demonstrate 7-fold enhanced exciton intensity when compared to emitters located on bare wafers, corresponding to a light collection efficiency (LCE) upmore » to 92% in the best case (average LCE of 69%) into a narrow output cone of +/-15 degrees that enables a priori fiber-to-chip butt coupling. The demonstrated MDA arrays are directly compatible with other quantum systems, particularly 2D materials, toward enabling efficient on-chip quantum light sources or spin-photon interfaces requiring unity light collection, both at cryogenic or room temperature.« less

76 FR 62004 - Revisions to the California State Implementation Plan, California Air Resources Board-Consumer...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-06

... comment includes Confidential Business Information (CBI) or other information whose disclosure is... the hard copy materials, please schedule an appointment during normal business hours with the contact... compounds with a global warming potential (GWP) of 150 or greater in Multi-purpose Solvents and Paint...

77 FR 5207 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Amendments to the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-02

... compound (VOC) emissions from industrial cleaning solvents facilities, automobile and light-duty truck... Organic Compounds,'' section 13.0, ``Automobile and Light-Duty Truck Coating Operations,'' section 16.0... requirements based on EPA CTGs. Amendments to section 13.0 establish (1) applicability for specific automobile...

77 FR 22224 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Amendments to the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-13

... of Volatile Organic Compounds Emissions; Automobile and Light-Duty Truck Coating Operations; Paper... compound (VOC) emissions from industrial cleaning solvents facilities; automobile and light-duty truck..., ``Automobile and Light-Duty Truck Coating Operations,'' section 16.0, ``Paper Coating,'' section 23.0...

78 FR 78726 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compound...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-27

... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R05-OAR-2012-0453; FRL-9904-35-Region 5... Control Measures for Industrial Solvent Cleaning for Northwest Indiana AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: The Environmental Protection Agency (EPA) is approving a...

78 FR 4800 - Approval and Promulgation of Air Quality Implementation Plans; Connecticut; Reasonably Available...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-23

... from cutback asphalt paving and solvent cleaning (metal degreasing). The original version of the state's cutback asphalt rule allowed use of cutback asphalt, with some restrictions, during the ozone season and provided exemptions for penetrating prime coat products and for long-term storage of asphalt...

Effects of intermolecular forces and backbone architecture on the phase behavior of fluorocopolymer-supercritical fluid mixtures

NASA Astrophysics Data System (ADS)

Mertdogan, Cynthia Asli

The impact of polymer backbone architecture on fluorocopolymer solubility in supercritical fluid (SCF) solvents is studied by systematically varying the chemical type of the repeat units in the main chain. The fluorocopolymers investigated include nonpolar copolymers of tetrafluoroethylene with 19 mol% hexafluoropropylene (FEPsb{19}) and 48 mol% hexafluoropropylene (FEPsb{48}) and a polar copolymer of vinylidene fluoride with 22 mol% hexafluoropropylene (Fluorelsp°ler ). The solvents are methodically varied from nonpolar perfluoroalkanes and SFsb6 to polar fluorocarbons and COsb2. Low molecular weight solvents are used to facilitate in interpreting the intermolecular forces that control fluorocopolymer solubility, although pressures in excess of 2,500 bar are sometimes needed to dissolve the fluorocopolymers in these simple solvents. Polarity effects, which vary inversely with temperature, are moderated by operating over a large temperature range from 0 to 300sp° C. A variable-volume view cell, capable of operating to high temperatures and high pressures, was designed and implemented to meet these extreme operating conditions. Increasing the polarizability of nonpolar solvents reduces the pressures required to dissolve FEPsb{19} by as much as 1,500 bar going from perfluoromethane to perfluoropropane. However, in polar solvents, the pressures required for FEPsb{19} solubility rise dramatically as the temperature is decreased due to the increase in polar, solvent-solvent interactions that do not favor the solubility of a nonpolar copolymer. Replacing semi-crystalline FEPsb{19} with amorphous FEPsb{48} yields the same trends in phase behavior. Therefore, crystallinity does not control the shape of these fluorocopolymer-SCF cloud-point curves. Adding a cosolvent to the solution can dramatically lower the pressures needed to dissolve the copolymer. Introducing the "cosolvent" directly into the polymer backbone by changing copolymer architecture is another method of modifying fluorocopolymer solubility as seen with the results for Fluorel-SCF mixtures compared to those for FEPsb{19}-SCF mixtures. A supercritical fractionation of FEPsb{19} provides information on the impact of molecular weight and end-group content on fluorocopolymer solubility. Challenges remain for modeling fluorocopolymer-solvent mixtures. The Sanchez-Lacombe equation cannot capture the characteristics of FEPsb{19}-SCF solvent phase behavior unless two empirical mixture parameters, one of which varies with temperature, are used.

Nuclear magnetic resonance studies of the solvation structures of a high-performance nonaqueous redox flow electrolyte

NASA Astrophysics Data System (ADS)

Deng, Xuchu; Hu, Mary; Wei, Xiaoliang; Wang, Wei; Mueller, Karl T.; Chen, Zhong; Hu, Jian Zhi

2016-03-01

Understanding the solvation structures of electrolytes is important for developing nonaqueous redox flow batteries that hold considerable potential for future large scale energy storage systems. The utilization of an emerging ionic-derivatived ferrocene compound, ferrocenylmethyl dimethyl ethyl ammonium bis(trifluoromethanesulfonyl)imide (Fc1N112-TFSI), has recently overcome the issue of solubility in the supporting electrolyte. In this work, 13C, 1H and 17O NMR investigations were carried out using electrolyte solutions consisting of Fc1N112-TFSI as the solute and the mixed alkyl carbonate as the solvent. It was observed that the spectra of 13C experience changes of chemical shifts while those of 17O undergo linewidth broadening, indicating interactions between solute and solvent molecules. Quantum chemistry calculations of both molecular structures and chemical shifts (13C, 1H and 17O) are performed for interpreting experimental results and for understanding the detailed solvation structures. The results indicate that Fc1N112-TFSI is dissociated at varying degrees in mixed solvent depending on concentrations. At dilute solute concentrations, most Fc1N112+ and TFSI- are fully disassociated with their own solvation shells formed by solvent molecules. At saturated concentration, Fc1N112+-TFSI- contact ion pairs are formed and the solvent molecules are preferentially interacting with the Fc rings rather than interacting with the ionic pendant arm of Fc1N112-TFSI.

Characterization and Remediation of Chlorinated Volatile Organic Contaminants in the Vadose Zone: An Overview of Issues and Approaches

PubMed Central

Brusseau, Mark L.; Carroll, Kenneth C.; Truex, Michael J.; Becker, David J.

2014-01-01

Contamination of vadose-zone systems by chlorinated solvents is widespread, and poses significant potential risk to human health through impacts on groundwater quality and vapor intrusion. Soil vapor extraction (SVE) is the presumptive remedy for such contamination, and has been used successfully for innumerable sites. However, SVE operations typically exhibit reduced mass-removal effectiveness at some point due to the impact of poorly accessible contaminant mass and associated mass-transfer limitations. Assessment of SVE performance and closure is currently based on characterizing contaminant mass discharge associated with the vadose-zone source, and its impact on groundwater or vapor intrusion. These issues are addressed in this overview, with a focus on summarizing recent advances in our understanding of the transport, characterization, and remediation of chlorinated solvents in the vadose zone. The evolution of contaminant distribution over time and the associated impacts on remediation efficiency will be discussed, as will the potential impact of persistent sources on groundwater quality and vapor intrusion. In addition, alternative methods for site characterization and remediation will be addressed. PMID:25383058

On the radiation stability of crown ethers in ionic liquids.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shkrob, I.; Marin, T.; Dietz, M.

2011-04-14

Crown ethers (CEs) are macrocyclic ionophores used for the separation of strontium-90 from acidic nuclear waste streams. Room temperature ionic liquids (ILs) are presently being considered as replacements for traditional molecular solvents employed in such separations. It is desirable that the extraction efficacy obtained with such solvents should not deteriorate in the strong radiation fields generated by decaying radionuclides. This deterioration will depend on the extent of radiation damage to both the IL solvent and the CE solute. While radiation damage to ILs has been extensively studied, the issue of the radiation stability of crown ethers, particularly in an ILmore » matrix, has not been adequately addressed. With this in mind, we have employed electron paramagnetic resonance (EPR) spectroscopy to study the formation of CE-related radicals in the radiolysis of selected CEs in ILs incorporating aromatic (imidazolium and pyridinium) cations. The crown ethers have been found to yield primarily hydrogen loss radicals, H atoms, and the formyl radical. In the low-dose regime, the relative yield of these radicals increases linearly with the mole fraction of the solute, suggesting negligible transfer of the excitation energy from the solvent to the solute; that is, the solvent has a 'radioprotective' effect. The damage to the CE in the loading region of practical interest is relatively low. Under such conditions, the main chemical pathway leading to decreased extraction performance is protonation of the macrocycle. At high radiation doses, sufficient to increase the acidity of the IL solvent significantly, such proton complexes compete with the solvent cations as electron traps. In this regime, the CEs will rapidly degrade as the result of H abstraction from the CE ring by the released H atoms. Thus, the radiation dose to which a CE/IL system is exposed must be maintained at a level sufficiently low to avoid this regime.« less

Techno-economic assessment of hybrid extraction and distillation processes for furfural production from lignocellulosic biomass.

PubMed

Nhien, Le Cao; Long, Nguyen Van Duc; Kim, Sangyong; Lee, Moonyong

2017-01-01

Lignocellulosic biomass is one of the most promising alternatives for replacing mineral resources to overcome global warming, which has become the most important environmental issue in recent years. Furfural was listed by the National Renewable Energy Laboratory as one of the top 30 potential chemicals arising from biomass. However, the current production of furfural is energy intensive and uses inefficient technology. Thus, a hybrid purification process that combines extraction and distillation to produce furfural from lignocellulosic biomass was considered and investigated in detail to improve the process efficiency. This effective hybrid process depends on the extracting solvent, which was selected based on a comprehensive procedure that ranged from solvent screening to complete process design. Various solvents were first evaluated in terms of their extraction ability. Then, the most promising solvents were selected to study the separation feasibility. Eventually, processes that used the three best solvents (toluene, benzene, and butyl chloride) were designed and optimized in detail using Aspen Plus. Sustainability analysis was performed to evaluate these processes in terms of their energy requirements, total annual costs (TAC), and carbon dioxide (CO 2 ) emissions. The results showed that butyl chloride was the most suitable solvent for the hybrid furfural process because it could save 44.7% of the TAC while reducing the CO 2 emissions by 45.5% compared to the toluene process. In comparison with the traditional purification process using distillation, this suggested hybrid extraction/distillation process can save up to 19.2% of the TAC and reduce 58.3% total annual CO 2 emissions. Furthermore, a sensitivity analysis of the feed composition and its effect on the performance of the proposed hybrid system was conducted. Butyl chloride was found to be the most suitable solvent for the hybrid extraction/distillation process of furfural production. The proposed hybrid sequence was more favorable than the traditional distillation process when the methanol fraction of the feed stream was <3% and more benefit could be obtained when that fraction decreased.

A review on methods of regeneration of spent pickling solutions from steel processing.

PubMed

Regel-Rosocka, Magdalena

2010-05-15

The review presents various techniques of regeneration of spent pickling solutions, including the methods with acid recovery, such as diffusion dialysis, electrodialysis, membrane electrolysis and membrane distillation, evaporation, precipitation and spray roasting as well as those with acid and metal recovery: ion exchange, retardation, crystallization solvent and membrane extraction. Advantages and disadvantages of the techniques are presented, discussed and confronted with the best available techniques requirements. Most of the methods presented meet the BAT requirements. The best available techniques are electrodialysis, diffusion dialysis and crystallization; however, in practice spray roasting and retardation/ion-exchange are applied most frequently for spent pickling solution regeneration. As "waiting for their chance" solvent extraction, non-dispersive solvent extraction and membrane distillation should be indicated because they are well investigated and developed. Environmental and economic benefits of the methods presented in the review depend on the cost of chemicals and wastewater treatment, legislative regulations and cost of modernization of existing technologies or implementation of new ones. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Two-photon absorption of [2.2]paracyclophane derivatives in solution: A theoretical investigation

NASA Astrophysics Data System (ADS)

Ferrighi, Lara; Frediani, Luca; Fossgaard, Eirik; Ruud, Kenneth

2007-12-01

The two-photon absorption of a class of [2.2]paracyclophane derivatives has been studied using quadratic response and density functional theories. For the molecules investigated, several effects influencing the two-photon absorption spectra have been investigated, such as side-chain elongation, hydrogen bonding, the use of ionic species, and solvent effects, the latter described by the polarizable continuum model. The calculations have been carried out using a recent parallel implementation of the polarizable continuum model in the DALTON code. Special attention is given to those aspects that could explain the large solvent effect on the two-photon absorption cross sections observed experimentally for this class of compounds.

Editorial of the PCCP themed issue on "Solvation Science".

PubMed

Morgenstern, Karina; Marx, Dominik; Havenith, Martina; Muhler, Martin

2015-04-07

The present special issue presents exciting experimental and theoretical results in the topic of "Solvation Science", a topic that emerges from physical, theoretical, and industrial chemistry, and is also of interest to a multitude of neighboring fields, such as inorganic and organic chemistry, biochemistry, physics and engineering. We hope that the articles will be highly useful for researchers who would like to enter this newly emerging area, and that it is a valuable source for the nucleation of new ideas and collaborations to better understand the active role of the solvent in reactions.

The optimization of phthalate analysis from plastic matrices by using GC/MS related techniques

NASA Astrophysics Data System (ADS)

Pusfitasari, Eka Dian; Hendarsyah, Hendris; Athaillah, Zatil Afrah

2017-11-01

Indication of malicious acts conducted by food vendors has been reported in many places in Indonesia and has been worrying the population. One of the issues is the indication that frying oil used by the vendors has been added with food packaging plastic to impart more crispy texture of the fried foods. One of the challenges for the monitoring process is to find suitable analytical method to identify this type of food adulteration. Because some food packaging, particularly from polyethylene group, contains plasticizer diethylhexylphthalate (DEHP), we intended to investigate the adulteration by detecting the phthalate compound. In this preliminary study, we focused on the optimization of GC equipment as well as the optimization of plastic extraction process with various types of solvents (hexane, dichloromethane, and acetonitrile) and extraction time (24, 48, and 72 hours). For 72-hour duration, treatment with solvent refreshment was also conducted to minimize solvent saturation effect. Our findings suggested that LOD and LOQ of the GC/MS instrument used for the DEHP analysis were 19.6 ng and 65.5 ng, respectively. In addition, it could be concluded that the process of plastic extraction through sonication for five minutes with n-hexane as a solvent resulted in the optimal value.

Size-controlled fabrication of zein nano/microparticles by modified anti-solvent precipitation with/without sodium caseinate

PubMed Central

Li, Feng; Chen, Yan; Liu, Shubo; Qi, Jian; Wang, Weiying; Wang, Chenhua; Zhong, Ruiyue; Chen, Zhijun; Li, Xiaoming; Guan, Yuanzhou; Kong, Wei; Zhang, Yong

2017-01-01

Zein-based nano/microparticles have been demonstrated to be promising carrier systems for both the food industry and biomedical applications. However, the fabrication of size-controlled zein particles has been a challenging issue. In this study, a modified anti-solvent precipitation method was developed, and the effects of various factors, such as mixing method, solvent/anti-solvent ratio, temperature, zein concentrations and the presence of sodium caseinate (SC) on properties of zein particles were investigated. Evidence is presented that, among the previously mentioned factors, the mixing method, especially mixing rate, could be used as an effective parameter to control the size of zein particles without changing other parameters. Moreover, through fine-tuning the mixing rate together with zein concentration, particles with sizes ranging from nanometers to micrometers and low polydispersity index values could be easily obtained. Based on the size-controlled fabrication method, SC-coated zein nanoparticles could also be obtained in a size-controlled manner by incubation of the coating material with the already-formed zein particles. The resultant nanoparticles showed better performance in both drug loading and controlled release, compared with zein/SC hybrid nanoparticles fabricated by adding aqueous ethanol solution to SC solution. The possible mechanisms of the nanoprecipitation process and self-assembly formation of these nanoparticles are discussed. PMID:29184408

Size-controlled fabrication of zein nano/microparticles by modified anti-solvent precipitation with/without sodium caseinate.

PubMed

Li, Feng; Chen, Yan; Liu, Shubo; Qi, Jian; Wang, Weiying; Wang, Chenhua; Zhong, Ruiyue; Chen, Zhijun; Li, Xiaoming; Guan, Yuanzhou; Kong, Wei; Zhang, Yong

2017-01-01

Zein-based nano/microparticles have been demonstrated to be promising carrier systems for both the food industry and biomedical applications. However, the fabrication of size-controlled zein particles has been a challenging issue. In this study, a modified anti-solvent precipitation method was developed, and the effects of various factors, such as mixing method, solvent/anti-solvent ratio, temperature, zein concentrations and the presence of sodium caseinate (SC) on properties of zein particles were investigated. Evidence is presented that, among the previously mentioned factors, the mixing method, especially mixing rate, could be used as an effective parameter to control the size of zein particles without changing other parameters. Moreover, through fine-tuning the mixing rate together with zein concentration, particles with sizes ranging from nanometers to micrometers and low polydispersity index values could be easily obtained. Based on the size-controlled fabrication method, SC-coated zein nanoparticles could also be obtained in a size-controlled manner by incubation of the coating material with the already-formed zein particles. The resultant nanoparticles showed better performance in both drug loading and controlled release, compared with zein/SC hybrid nanoparticles fabricated by adding aqueous ethanol solution to SC solution. The possible mechanisms of the nanoprecipitation process and self-assembly formation of these nanoparticles are discussed.

Online hydrogen/deuterium exchange performed in the ion mobility cell of a hybrid mass spectrometer.

PubMed

Nagy, Kornél; Redeuil, Karine; Rezzi, Serge

2009-11-15

The present paper describes the performance of online, gas-phase hydrogen/deuterium exchange implemented in the ion mobility cell of a quadrupole time-of-flight mass spectrometer. Deuterium oxide and deuterated methanol were utilized to create deuterated vapor that is introduced into the ion mobility region of the mass spectrometer. Hydrogen/deuterium exchange occurs spontaneously in the milliseconds time frame without the need of switching the instrument into ion mobility mode. The exchange was studied in case of low molecular weight molecules and proteins. The observed number of exchanged hydrogens was equal to the number of theoretically exchangeable hydrogens for all low molecular weight compounds. This method needs only minimal instrumental modifications, is simple, cheap, environment friendly, compatible with ultraperformance liquid chromatography, and can be implemented on commercially available instruments. It does not compromise choice of liquid chromatographic solvents and accurate mass or parallel-fragmentation (MS(E)) methods. The performance of this method was compared to that of conventional alternatives where the deuterated solvent is introduced into the cone gas of the instrument. Although the degree of exchange was similar between the two methods, the "cone gas method" requires 10 times higher deuterated solvent volumes (50 muL/min) and offers reduced sensitivity in the tandem mass spectrometry (MS/MS) mode. The presented method is suggested as a standard future element of mass spectrometers to aid online structural characterization of unknowns and to study conformational changes of proteins with hydrogen/deuterium exchange.

Development of the Next-Generation Caustic-Side Solvent Extraction (NG-CSSX) Process for Cesium Removal from High-Level Tank Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moyer, Bruce A; Bonnesen, Peter V; Delmau, Laetitia Helene

2011-01-01

This paper describes the chemical performance of the Next-Generation Caustic-Side Solvent Extraction (NG-CSSX) process in its current state of development for removal of cesium from the alkaline high-level tank wastes at the Savannah River Site (SRS) in the US Department of Energy (USDOE) complex. Overall, motivation for seeking a major enhancement in performance for the currently deployed CSSX process stems from needs for accelerating the cleanup schedule and reducing the cost of salt-waste disposition. The primary target of the NG-CSSX development campaign in the past year has been to formulate a solvent system and to design a corresponding flowsheet thatmore » boosts the performance of the SRS Modular CSSX Unit (MCU) from a current minimum decontamination factor of 12 to 40,000. The chemical approach entails use of a more soluble calixarene-crown ether, called MaxCalix, allowing the attainment of much higher cesium distribution ratios (DCs) on extraction. Concurrently decreasing the Cs-7SB modifier concentration is anticipated to promote better hydraulics. A new stripping chemistry has been devised using a vitrification-friendly aqueous boric acid strip solution and a guanidine suppressor in the solvent, resulting in sharply decreased DCs on stripping. Results are reported herein on solvent phase behavior and batch Cs distribution for waste simulants and real waste together with a preliminary flowsheet applicable for implementation in the MCU. The new solvent will enable MCU to process a much wider range of salt feeds and thereby extend its service lifetime beyond its design life of three years. Other potential benefits of NG-CSSX include increased throughput of the SRS Salt Waste Processing Facility (SWPF), currently under construction, and an alternative modular near-tank application at Hanford.« less

Membrane-Based Technologies in the Pharmaceutical Industry and Continuous Production of Polymer-Coated Crystals/Particles.

PubMed

Chen, Dengyue; Sirkar, Kamalesh K; Jin, Chi; Singh, Dhananjay; Pfeffer, Robert

2017-01-01

Membrane technologies are of increasing importance in a variety of separation and purification applications involving liquid phases and gaseous mixtures. Although the most widely used applications at this time are in water treatment including desalination, there are many applications in chemical, food, healthcare, paper and petrochemical industries. This brief review is concerned with existing and emerging applications of various membrane technologies in the pharmaceutical and biopharmaceutical industry. The goal of this review article is to identify important membrane processes and techniques which are being used or proposed to be used in the pharmaceutical and biopharmaceutical operations. How novel membrane processes can be useful for delivery of crystalline/particulate drugs is also of interest. Membrane separation technologies are extensively used in downstream processes for bio-pharmaceutical separation and purification operations via microfiltration, ultrafiltration and diafiltration. Also the new technique of membrane chromatography allows efficient purification of monoclonal antibodies. Membrane filtration techniques of reverse osmosis and nanofiltration are being combined with bioreactors and advanced oxidation processes to treat wastewaters from pharmaceutical plants. Nanofiltration with organic solvent-stable membranes can implement solvent exchange and catalyst recovery during organic solvent-based drug synthesis of pharmaceutical compounds/intermediates. Membranes in the form of hollow fibers can be conveniently used to implement crystallization of pharmaceutical compounds. The novel crystallization methods of solid hollow fiber cooling crystallizer (SHFCC) and porous hollow fiber anti-solvent crystallization (PHFAC) are being developed to provide efficient methods for continuous production of polymer-coated drug crystals in the area of drug delivery. This brief review provides a general introduction to various applications of membrane technologies in the pharmaceutical/biopharmaceutical industry with special emphasis on novel membrane techniques for pharmaceutical applications. The method of coating a drug particle with a polymer using the SHFCC method is stable and ready for scale-up for operation over an extended period. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

40 CFR 63.4710 - What notifications must I submit?

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 63.9(h). (1) Company name and address. (2) Statement by a responsible official with that official's... section do not apply to solvent recovery systems for which you conduct liquid-liquid material balances... of whether or not you developed and implemented the work practice plan required by § 63.4693. ...

40 CFR 63.4110 - What notifications must I submit?

Code of Federal Regulations, 2010 CFR

2010-07-01

... this section and the applicable information specified in § 63.9(h). (1) Company name and address. (2... solvent recovery systems for which you conduct liquid-liquid material balances according to § 63.4161(h... not you developed and implemented the work practice plan required by § 63.4093. (v) A statement of...

77 FR 59090 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Adhesives and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-26

... material, such as copyrighted material, is not placed on the Internet and will be publicly available only..., sealants, primers, and solvents (76 FR 53369, August 26, 2011). The formal SIP revision was submitted by... federally enforceable rule: Emission limitations, compliance procedures and test methods, compliance dates...

3D investigation on polystyrene colloidal crystals by floatage self-assembly with mixed solvent via synchrotron radiation x-ray phase-contrast computed tomography

NASA Astrophysics Data System (ADS)

Fu, Yanan; Xie, Honglan; Deng, Biao; Du, Guohao; Xiao, Tiqiao

2017-06-01

The floatage self-assembly method was introduced with mixed solvent as the medium of polystyrene sphere suspension to fabricate the colloidal crystal. The three dimensional (3D) void system of the colloidal crystal was noninvasively characterized by synchrotron radiation phase-contrast computed tomography, and the quantitative image analysis was implemented aiming to the polystyrene sphere colloidal crystal. Comparing with gravity sedimentation method, the three samples fabricated from floatage self-assembly with mixed solvents have the lowest porosity, and when ethylene glycol and water were mixed with ratio of 1:1, the lowest porosity of 27.49% could be achieved, that has been very close to the minimum porosity of ordered 3D monodisperse sphere array (26%). In single slices, the porosities and fractal dimension for the voids were calculated. The results showed that two factors would significantly influence the porosity of the whole colloidal crystal: the first deposited sphere layer's orderliness and the sedimentation speed of the spheres. The floatage self-assembly could induce a stable close-packing process, resulted from the powerful nucleation force-lateral capillary force coupled with the mixed solvent to regulate the floating upward speed for purpose of matching the assembly rate.

Green approach using monolithic column for simultaneous determination of coformulated drugs.

PubMed

Yehia, Ali M; Mohamed, Heba M

2016-06-01

Green chemistry and sustainability is now entirely encompassed across the majority of pharmaceutical companies and research labs. Researchers' attention is careworn toward implementing the green analytical chemistry principles for more eco-friendly analytical methodologies. Solvents play a dominant role in determining the greenness of the analytical procedure. Using safer solvents, the greenness profile of the methodology could be increased remarkably. In this context, a green chromatographic method has been developed and validated for the simultaneous determination of phenylephrine, paracetamol, and guaifenesin in their ternary pharmaceutical mixture. The chromatographic separation was carried out using monolithic column and green solvents as mobile phase. The use of monolithic column allows efficient separation protocols at higher flow rates, which results in short time of analysis. Two-factor three-level experimental design was used to optimize the chromatographic conditions. The greenness profile of the proposed methodology was assessed using eco-scale as a green metrics and was found to be an excellent green method with regard to the usage and production of hazardous chemicals and solvents, energy consumption, and amount of produced waste. The proposed method improved the environmental impact without compromising the analytical performance criteria and could be used as a safer alternate for the routine analysis of the studied drugs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potential of mean force for ion pairs in non-aqueous solvents. Comparison of polarizable and non-polarizable MD simulations

NASA Astrophysics Data System (ADS)

Odinokov, A. V.; Leontyev, I. V.; Basilevsky, M. V.; Petrov, N. Ch.

2011-01-01

Potentials of mean force (PMF) are calculated for two model ion pairs in two non-aqueous solvents. Standard non-polarizable molecular dynamics simulation (NPMD) and approximate polarizable simulation (PMD) are implemented and compared as tools for monitoring PMF profiles. For the polar solvent (dimethylsulfoxide, DMSO) the PMF generated in terms of the NPMD reproduces fairly well the refined PMD-PMF profile. For the non-polar solvent (benzene) the conventional NPMD computation proves to be deficient. The validity of the correction found in terms of the approximate PMD approach is verified by its comparison with the result of the explicit PMD computation in benzene. The shapes of the PMF profiles in DMSO and in benzene are quite different. In DMSO, owing to dielectric screening, the PMF presents a flat plot with a shallow minimum positioned in the vicinity of the van der Waals contact of the ion pair. For the benzene case, the observed minimum proves to be unexpectedly deep, which manifests the formation of a tightly-binded contact ion pair. This remarkable effect arises owing to the strong electrostatic interaction that is incompletely screened by a non-polar medium. The PMFs for the binary benzene/DMSO mixtures display intermediate behaviour depending on the DMSO content.

Phase-field approach to implicit solvation of biomolecules with Coulomb-field approximation

NASA Astrophysics Data System (ADS)

Zhao, Yanxiang; Kwan, Yuen-Yick; Che, Jianwei; Li, Bo; McCammon, J. Andrew

2013-07-01

A phase-field variational implicit-solvent approach is developed for the solvation of charged molecules. The starting point of such an approach is the representation of a solute-solvent interface by a phase field that takes one value in the solute region and another in the solvent region, with a smooth transition from one to the other on a small transition layer. The minimization of an effective free-energy functional of all possible phase fields determines the equilibrium conformations and free energies of an underlying molecular system. All the surface energy, the solute-solvent van der Waals interaction, and the electrostatic interaction are coupled together self-consistently through a phase field. The surface energy results from the minimization of a double-well potential and the gradient of a field. The electrostatic interaction is described by the Coulomb-field approximation. Accurate and efficient methods are designed and implemented to numerically relax an underlying charged molecular system. Applications to single ions, a two-plate system, and a two-domain protein reveal that the new theory and methods can capture capillary evaporation in hydrophobic confinement and corresponding multiple equilibrium states as found in molecular dynamics simulations. Comparisons of the phase-field and the original sharp-interface variational approaches are discussed.

Optimizing surface finishing processes through the use of novel solvents and systems

NASA Astrophysics Data System (ADS)

Quillen, M.; Holbrook, P.; Moore, J.

2007-03-01

As the semiconductor industry continues to implement the ITRS (International Technology Roadmap for Semiconductors) node targets that go beyond 45nm [1], the need for improved cleanliness between repeated process steps continues to grow. Wafer cleaning challenges cover many applications such as Cu/low-K integration, where trade-offs must be made between dielectric damage and residue by plasma etching and CMP or moisture uptake by aqueous cleaning products. [2-5] Some surface sensitive processes use the Marangoni tool design [6] where a conventional solvent such as IPA (isopropanol), combines with water to provide improved physical properties such as reduced contact angle and surface tension. This paper introduces the use of alternative solvents and their mixtures compared to pure IPA in removing ionics, moisture, and particles using immersion bench-chemistry models of various processes. A novel Eastman proprietary solvent, Eastman methyl acetate is observed to provide improvement in ionic, moisture capture, and particle removal, as compared to conventional IPA. [7] These benefits may be improved relative to pure IPA, simply by the addition of various additives. Some physical properties of the mixtures were found to be relatively unchanged even as measured performance improved. This report presents our attempts to cite and optimize these benefits through the use of laboratory models.

MICROSPED Information Bulletin, Issues 1-10, 1984. Microcomputers in the Schools--Implementation in Special Education.

ERIC Educational Resources Information Center

Hanley, Tom V., Ed.; And Others

1984-01-01

Ten information bulletins on the implementation of microcomputers in special education are presented. Topics covered include the following: (1) implementation issues (including a description of a study assessing microcomputer applications in 12 local school districts' special education programs); (2) implementation strategies (which focuses on…

Restoration of paper artworks with microemulsions confined in hydrogels for safe and efficient removal of adhesive tapes.

PubMed

Bonelli, Nicole; Montis, Costanza; Mirabile, Antonio; Berti, Debora; Baglioni, Piero

2018-05-21

The presence of pressure-sensitive tapes (PSTs) on paper artworks, either fortuitous or specifically applied for conservation purposes, is one of the most frequent and difficult issues encountered during restoration. Aged PSTs can damage or disfigure artworks, compromising structural integrity, readability, and enjoyment. Current procedures are often inherently hazardous for artistic media and paper support. Challenged by the necessity to remove PSTs from a contemporary and an ancient drawing (20th century, by artists da Silva and Hayter, and a 16th century drawing of one figure from the Sistine Chapel by Michelangelo), we addressed this issue from a physicochemical perspective, leveraging colloid and interface science. After a characterization of the specific PSTs present on the artifact, we selected a highly water-retentive hydrogel as the host of 23% wt/wt of "green" organic solvents uniformly dispersed within the gel in the form of nanosized droplets. The double confinement of the organic solvent in the nanodroplets and into the gel network promotes a tailored, controlled removal of PSTs of different natures, with virtually no interaction with the solvent-sensitive artwork. This noninvasive procedure allows complete retrieval of artwork readability. For instance, in the ancient drawing, the PST totally concealed the inscription, " di mano di Michelangelo " ("from Michelangelo's hand"), a possibly false attribution hidden by a collector, which is now perfectly visible and whose origin is currently under investigation. Remarkably, the same methodology was successful for the removal of aged PST adhesive penetrated inside paper fibers of a drawing from the celebrated artist Lucio Fontana.

Implementation of a Point-of-Care Radiologist-Technologist Communication Tool in a Quality Assurance Program.

PubMed

Ong, Leonard; Elnajjar, Pierre; Nyman, C Gregory; Mair, Thomas; Juluru, Krishna

2017-07-01

We implemented an Image Quality Reporting and Tracking Solution (IQuaRTS), directly linked from the PACS, to improve communication between radiologists and technologists. IQuaRTS launched in May 2015. We compared MRI issues filed in the period before IQuaRTS implementation (May-September 2014) using a manual system with MRI issues filed in the IQuaRTS period (May-September 2015). The unpaired t test was used for analysis. For assessment of overall results in the IQuaRTS period alone, all issues filed across all modalities were included. Summary statistics and charts were generated using Excel and Tableau. For MRI issues, the number of issues filed during the IQuaRTS period was 498 (2.5% of overall MRI examination volume) compared with 78 issues filed during the period before IQuaRTS implementation (0.4% of total examination volume) (p = 0.0001), representing a 625% relative increase. Tickets that documented excellent work were 8%. Other issues included images not pushed to PACS (20%), film library issues (19%), and documentation or labeling (8%). Of the issues filed, 55% were MRI-related and 25% were CT-related. The issues were stratified across six sites within our institution. Staff requiring additional training could be readily identified, and 80% of the issues were resolved within 72 hours. IQuaRTS is a cost-effective online issue reporting tool that enables robust data collection and analytics to be incorporated into quality improvement programs. One limitation of the system is that it must be implemented in an environment where staff are receptive to quality improvement.

Matrix precipitation: a general strategy to eliminate matrix interference for pharmaceutical toxic impurities analysis.

PubMed

Yang, Xiaojing; Xiong, Xuewu; Cao, Ji; Luan, Baolei; Liu, Yongjun; Liu, Guozhu; Zhang, Lei

2015-01-30

Matrix interference, which can lead to false positive/negative results, contamination of injector or separation column, incompatibility between sample solution and the selected analytical instrument, and response inhibition or even quenching, is commonly suffered for the analysis of trace level toxic impurities in drug substance. In this study, a simple matrix precipitation strategy is proposed to eliminate or minimize the above stated matrix interference problems. Generally, a sample of active pharmaceutical ingredients (APIs) is dissolved in an appropriate solvent to achieve the desired high concentration and then an anti-solvent is added to precipitate the matrix substance. As a result, the target analyte is extracted into the mixed solution with very less residual of APIs. This strategy has the characteristics of simple manipulation, high recovery and excellent anti-interference capability. It was found that the precipitation ratio (R, representing the ability to remove matrix substance) and the proportion of solvent (the one used to dissolve APIs) in final solution (P, affecting R and also affecting the method sensitivity) are two important factors of the precipitation process. The correlation between R and P was investigated by performing precipitation with various APIs in different solvent/anti-solvent systems. After a detailed mathematical reasoning process, P=20% was proved to be an effective and robust condition to perform the precipitation strategy. The precipitation method with P=20% can be used as a general strategy for toxic impurity analysis in APIs. Finally, several typical examples are described in this article, where the challenging matrix interference issues have been resolved successfully. Copyright © 2014 Elsevier B.V. All rights reserved.

Compliance with the Aerospace MACT Standard at Lockheed Martin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurucz, K.L.; Vicars, S.; Fetter, S.

1997-12-31

Actions taken and planned at four Lockheed Martin Corporation (LMC) facilities to comply with the Aerospace MACT Standard are reviewed. Many LMC sites have taken proactive steps to reduce emissions and implement low VOC coating technology. Significant administrative, facility, and material challenges remain to achieve compliance with the upcoming NESHAP and Control Technology Guideline (CTG) standards. The facilities discussed herein set up programs to develop and implement compliance strategies. These facilities manufacture military aircraft, missiles, satellites, rockets, and electronic guidance and communications systems. Some of the facilities are gearing up for new production lines subject to new source MACT standards.more » At this time the facilities are reviewing compliance status of all primers, topcoats, maskants and solvents subject to the standard. Facility personnel are searching for the most efficient methods of satisfying the recordkeeping, reporting and monitoring, sections of the standards while simultaneously preparing or reviewing their Title V permit applications. Facility decisions on paint booths are the next highest priority. Existing dry filter paint booths will be subject to the filtration standard for existing paint booths which requires the use of two-stage filters. Planned paint booths for the F-22 program, and other new booths must comply with the standard for new and rebuilt booths which requires three stage or HEPA filters. Facilities looking to replace existing water wash paint booths, and those required to retrofit the air handling equipment to accommodate the two-stage filters, are reviewing issues surrounding the rebuilt source definition.« less

Translating Research to Practice: Overcoming Barriers to Implementing Effective Off-Campus Party Intervention. Issues in Prevention

ERIC Educational Resources Information Center

Higher Education Center for Alcohol, Drug Abuse, and Violence Prevention, 2012

2012-01-01

This issue of "Issues in Prevention" focuses on overcoming barriers in implementing effective off-campus party intervention. This issue contains the following articles: (1) Confronting the Problems Associated With Off-Campus Parties With Evidence-Based Strategies (John D. Clapp); (2) Overview of Research on Effective Off-Campus Party…

12 CFR 1204.1 - Why did FHFA issue this part?

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Why did FHFA issue this part? 1204.1 Section 1204.1 Banks and Banking FEDERAL HOUSING FINANCE AGENCY ORGANIZATION AND OPERATIONS PRIVACY ACT IMPLEMENTATION § 1204.1 Why did FHFA issue this part? FHFA issued this part to: (a) Implement the Privacy Act of...

Discovering Green, Aqueous Suzuki Coupling Reactions: Synthesis of Ethyl (4-Phenylphenyl)Acetate, a Biaryl with Anti-Arthritic Potential

ERIC Educational Resources Information Center

Costa, Nancy E.; Pelotte, Andrea L.; Simard, Joseph M.; Syvinski, Christopher A.; Deveau, Amy M.

2012-01-01

Suzuki couplings are powerful chemical reactions commonly employed in academic and industrial research settings to generate functionalized biaryls. We have developed and implemented a discovery-based, microscale experiment for the undergraduate organic chemistry laboratory that explores green Suzuki coupling using water as the primary solvent.…

System Issues Related to Implementing on the Internet

NASA Technical Reports Server (NTRS)

Mackey, William; Bagg, Thomas C., III

1999-01-01

Implementing capabilities on the World Wide Web should never be taken lightly. A good systems engineer is able to examine such implementations from all points of view, including political, legal, security, access, technical deployment, and quality. The evacuation discussed in this paper was conducted to ensure that the National Aeronautics and Space Administration (NASA) was proceeding in a correct direction by implementing RECALL a Lessons Learned System on the Web and, subsequently, did so successfully. The systems approach extended well beyond technical implementation to several issue that are not often addressed by an implementation team. The resulting evaluation increased the team's sensitivity to such issues and, in fact, the authors believe that the evaluation provided as much benefit as the system itself.

Routine Microsecond Molecular Dynamics Simulations with AMBER on GPUs. 1. Generalized Born

PubMed Central

2012-01-01

We present an implementation of generalized Born implicit solvent all-atom classical molecular dynamics (MD) within the AMBER program package that runs entirely on CUDA enabled NVIDIA graphics processing units (GPUs). We discuss the algorithms that are used to exploit the processing power of the GPUs and show the performance that can be achieved in comparison to simulations on conventional CPU clusters. The implementation supports three different precision models in which the contributions to the forces are calculated in single precision floating point arithmetic but accumulated in double precision (SPDP), or everything is computed in single precision (SPSP) or double precision (DPDP). In addition to performance, we have focused on understanding the implications of the different precision models on the outcome of implicit solvent MD simulations. We show results for a range of tests including the accuracy of single point force evaluations and energy conservation as well as structural properties pertainining to protein dynamics. The numerical noise due to rounding errors within the SPSP precision model is sufficiently large to lead to an accumulation of errors which can result in unphysical trajectories for long time scale simulations. We recommend the use of the mixed-precision SPDP model since the numerical results obtained are comparable with those of the full double precision DPDP model and the reference double precision CPU implementation but at significantly reduced computational cost. Our implementation provides performance for GB simulations on a single desktop that is on par with, and in some cases exceeds, that of traditional supercomputers. PMID:22582031

Pristine Stratospheric Collections of Cosmic Dust

NASA Technical Reports Server (NTRS)

Messenger, S.; Keller, L. P.; Nakamura-Messenger, K.; Clemett, S. J.

2012-01-01

Since 1981, NASA has routinely collected interplanetary dust particles (IDPs) in the stratosphere by inertial impact onto silicone oil-coated flat plate collectors deployed on the wings of high-altitude aircraft [1]. The highly viscous oil traps and localizes the particles, which can fragment during collection. Particles are removed from the collectors with a micromanipulator and washed of the oil using organic solvents, typically hexane or xylene. While silicone oil is an efficient collection medium, its use is problematic. All IDPs are initially coated with this material (polydimethylsiloxane, n(CH3)2SiO) and traces of oil may remain after cleaning. The solvent rinse itself is also a concern as it likely removes indigenous organics from the particles. To avoid these issues, we used a polyurethane foam substrate for the oil-free stratospheric collection of IDPs.

Environmental Application, Fate, Effects, and Concerns of Ionic Liquids: A Review.

PubMed

Amde, Meseret; Liu, Jing-Fu; Pang, Long

2015-11-03

Ionic liquids (ILs) comprise mostly of organic salts with negligible vapor pressure and low flammability that are proposed as replacements for volatile solvents. ILs have been promoted as "green" solvents and widely investigated for their various applications. Although the utility of these chemicals is unquestionable, their toxic effects have attracted great attention. In order to manage their potential hazards and design environmentally benign ILs, understanding their environmental behavior, fate and effects is important. In this review, environmentally relevant issues of ILs, including their environmental application, environmental behavior and toxicity are addressed. In addition, also presented are the influence of ILs on the environmental fate and toxicity of other coexisting contaminants, important routes for designing nontoxic ILs and the techniques that might be adopted for the removal of ILs.

Random copolymers that protect proteins

NASA Astrophysics Data System (ADS)

Alexander-Katz, Alfredo; Van Lehn, Reid C.

2018-03-01

Scientists have tried and in some limited cases succeeded to harness proteins to do chemistry (1) or use them in functional materials. However, most proteins only function correctly if they fold into specific conformations, which typically occurs with the assistance of other proteins (such as chaperones, translocons, or transporters) that mediate structure formation, membrane insertion, and intracellular trafficking (2, 3). Several methods have been used to improve protein stability in nonbiological environments—including micelle encapsulation, polymer conjugation, and sol-gel trapping (4)—but for most intended applications, they suffer from low levels of functionality, difficult chemical postfunctionalization, or the requirement of very specific solvent environments. On page 1239 of this issue, Panganiban et al. (5) introduce an approach for stabilizing proteins in disparate solvent environments that does not suffer from these drawbacks.

Putting proteins back into water

NASA Astrophysics Data System (ADS)

de Los Rios, Paolo; Caldarelli, Guido

2000-12-01

We introduce a simplified protein model where the solvent (water) degrees of freedom appear explicitly (although in an extremely simplified fashion). Using this model we are able to recover the thermodynamic phenomenology of proteins over a wide range of temperatures. In particular we describe both the warm and the cold protein denaturation within a single framework, while addressing important issues about the structure of model proteins.

Nanocarrier for poorly water-soluble anticancer drugs--barriers of translation and solutions.

PubMed

Narvekar, Mayuri; Xue, Hui Yi; Eoh, June Young; Wong, Ho Lun

2014-08-01

Many existing chemotherapeutic drugs, repurposed drugs and newly developed small-molecule anticancer compounds have high lipophilicity and low water-solubility. Currently, these poorly water-soluble anticancer drugs (PWSAD) are generally solubilized using high concentrations of surfactants and co-solvents, which frequently lead to adverse side effects. In recent years, researchers have been actively exploring the use of nanotechnology as an alternative to the solvent-based drug solubilization approach. Several classes of nanocarrier systems (lipid-based, polymer-based and albumin-based) are widely studied for encapsulation and delivery of the existing and new PWSAD. These nanocarriers were also shown to offer several additional advantages such as enhanced tumour accumulation, reduced systemic toxicity and improved therapeutic effectiveness. In this article, the recent nanotechnological advances in PWSAD delivery will be reviewed. The barriers commonly encountered in the development of PWSAD nanoformulations (e.g. formulation issues and nanotoxicity issues) and the strategies to overcome these barriers will also be discussed. It is our goal to provide the pharmaceutical scientists and clinicians with more in-depth information about the nanodelivery approach, thus, more efficacious and safe PWSAD nanoformulations can be developed with improved translational success.

Linear response coupled cluster theory with the polarizable continuum model within the singles approximation for the solvent response.

PubMed

Caricato, Marco

2018-04-07

We report the theory and the implementation of the linear response function of the coupled cluster (CC) with the single and double excitations method combined with the polarizable continuum model of solvation, where the correlation solvent response is approximated with the perturbation theory with energy and singles density (PTES) scheme. The singles name is derived from retaining only the contribution of the CC single excitation amplitudes to the correlation density. We compare the PTES working equations with those of the full-density (PTED) method. We then test the PTES scheme on the evaluation of excitation energies and transition dipoles of solvated molecules, as well as of the isotropic polarizability and specific rotation. Our results show a negligible difference between the PTED and PTES schemes, while the latter affords a significantly reduced computational cost. This scheme is general and can be applied to any solvation model that includes mutual solute-solvent polarization, including explicit models. Therefore, the PTES scheme is a competitive approach to compute response properties of solvated systems using CC methods.

Linear response coupled cluster theory with the polarizable continuum model within the singles approximation for the solvent response

NASA Astrophysics Data System (ADS)

Caricato, Marco

2018-04-01

We report the theory and the implementation of the linear response function of the coupled cluster (CC) with the single and double excitations method combined with the polarizable continuum model of solvation, where the correlation solvent response is approximated with the perturbation theory with energy and singles density (PTES) scheme. The singles name is derived from retaining only the contribution of the CC single excitation amplitudes to the correlation density. We compare the PTES working equations with those of the full-density (PTED) method. We then test the PTES scheme on the evaluation of excitation energies and transition dipoles of solvated molecules, as well as of the isotropic polarizability and specific rotation. Our results show a negligible difference between the PTED and PTES schemes, while the latter affords a significantly reduced computational cost. This scheme is general and can be applied to any solvation model that includes mutual solute-solvent polarization, including explicit models. Therefore, the PTES scheme is a competitive approach to compute response properties of solvated systems using CC methods.

Microchip electrospray: improvements in spray and signal stability during gradient elution by an inverted postcolumn makeup flow.

PubMed

Jung, Stephanie; Effelsberg, Uwe; Tallarek, Ulrich

2011-12-01

Dynamic changes in mobile phase composition during high-performance liquid chromatography (HPLC) gradient elution coupled to mass spectrometry (MS) sensitively affect electrospray modes. We investigate the impact of the eluent composition on spray stability and MS response by infusion and injection experiments with a small tetrapeptide in water-acetonitrile mixtures. The employed HPLC/electrospray (ESI)-MS configuration uses a microchip equipped with an enrichment column, a separation column, and a makeup flow (MUF) channel. One nano pump is connected to the separation column, while a second one delivers solvent of exactly inverted composition to the MUF channel. Both solvent streams are united behind the separation column, before the ESI tip, such that the resulting electrosprayed solution always has identical composition during a gradient elution. Analyte peak parameters without and with MUF compensation are determined and discussed with respect to the electrospray mode and eluent composition. The postcolumn MUF significantly improves spray and signal stability over the entire solvent gradient, without compromising the performance of the HPLC separation column. It can also be conveniently implemented on microchip platforms.

A generalized method for alignment of block copolymer films: solvent vapor annealing with soft shear.

PubMed

Qiang, Zhe; Zhang, Yuanzhong; Groff, Jesse A; Cavicchi, Kevin A; Vogt, Bryan D

2014-08-28

One of the key issues associated with the utilization of block copolymer (BCP) thin films in nanoscience and nanotechnology is control of their alignment and orientation over macroscopic dimensions. We have recently reported a method, solvent vapor annealing with soft shear (SVA-SS), for fabricating unidirectional alignment of cylindrical nanostructures. This method is a simple extension of the common SVA process by adhering a flat, crosslinked poly(dimethylsiloxane) (PDMS) pad to the BCP thin film. The impact of processing parameters, including annealing time, solvent removal rate and the physical properties of the PDMS pad, on the quality of alignment quantified by the Herman's orientational factor (S) is systematically examined for a model system of polystyrene-block-polyisoprene-block-polystyrene (SIS). As annealing time increases, the SIS morphology transitions from isotropic rods to highly aligned cylinders. Decreasing the rate of solvent removal, which impacts the shear rate imposed by the contraction of the PDMS, improves the orientation factor of the cylindrical domains; this suggests the nanostructure alignment is primarily induced by contraction of PDMS during solvent removal. Moreover, the physical properties of the PDMS controlled by the crosslink density impact the orientation factor by tuning its swelling extent during SVA-SS and elastic modulus. Decreasing the PDMS crosslink density increases S; this effect appears to be primarily driven by the changes in the solubility of the SVA-SS solvent in the PDMS. With this understanding of the critical processing parameters, SVA-SS has been successfully applied to align a wide variety of BCPs including polystyrene-block-polybutadiene-block-polystyrene (SBS), polystyrene-block-poly(N,N-dimethyl-n-octadecylammonium p-styrenesulfonate) (PS-b-PSS-DMODA), polystyrene-block-polydimethylsiloxane (PS-b-PDMS) and polystyrene-block-poly(2-vinlypyridine) (PS-b-P2VP). These results suggest that SVA-SS is a generalizable method for the alignment of BCP thin films.

Issues Management Process Course # 38401

DOE Office of Scientific and Technical Information (OSTI.GOV)

Binion, Ula Marie

The purpose of this training it to advise Issues Management Coordinators (IMCs) on the revised Contractor Assurance System (CAS) Issues Management (IM) process. Terminal Objectives: Understand the Laboratory’s IM process; Understand your role in the Laboratory’s IM process. Learning Objectives: Describe the IM process within the context of the CAS; Describe the importance of implementing an institutional IM process at LANL; Describe the process flow for the Laboratory’s IM process; Apply the definition of an issue; Use available resources to determine initial screening risk levels for issues; Describe the required major process steps for each risk level; Describe the personnelmore » responsibilities for IM process implementation; Access available resources to support IM process implementation.« less

Design of a Blended Learning Environment: Considerations and Implementation Issues

ERIC Educational Resources Information Center

Gedik, Nuray; Kiraz, Ercan; Ozden, M. Yasar

2013-01-01

This study identified critical issues in the design of a blended learning environment by examining basic design considerations and implementation issues. Following a design-based research approach with the phenomenological tradition of qualitative research, the study investigated instructor experiences relating to the design, development, and…

Master's Program Module "Environmental Issues--Decision Making Experience" as Precondition for Implementation of Education for Sustainable Development for Professional Training of Teachers

ERIC Educational Resources Information Center

Vinokurova, Natalia Fedorovna; Martilova, Natalia Viktorovna; Krivdina, Irina Yurievna; Badin, Mikhail Mikhailovich; Efimova, Olga Evgenyevna

2016-01-01

The article discusses current issues related to the implementation of the UNESCO roadmap implementing Global action programme on education for sustainable development. In the context of increasing the professional level of pedagogical workers is a priority area in the implementation of education for sustainable development. Therefore, we believe…

A solvent-free microbial-activated air cathode battery paper platform made with pencil-traced graphite electrodes.

PubMed

Lee, Seung Ho; Ban, Ju Yeon; Oh, Chung-Hun; Park, Hun-Kuk; Choi, Samjin

2016-06-23

We present the fabrication of an ultra-low cost, disposable, solvent-free air cathode all-paper microbial fuel cell (MFC) that does not utilize any chemical treatments. The anode and cathode were fabricated by depositing graphite particles by drawing them on paper with a pencil (four strokes). Hydrophobic parchment paper was used as a proton exchange membrane (PEM) to allow only H(+) to pass. Air cathode MFC technology, where O2 was used as an electron acceptor, was implemented on the paper platform. The bioelectric current was generated by an electrochemical process involving the redox couple of microbial-activated extracellular electron transferred electrons, PEM-passed H(+), and O2 in the cathode. A fully micro-integrated pencil-traced MFC showed a fast start-time, producing current within 10 s after injection of bacterial cells. A single miniaturized all-paper air cathode MFC generated a maximum potential of 300 mV and a maximum current of 11 μA during 100 min after a single injection of Shewanella oneidensis. The micro-fabricated solvent-free air cathode all-paper MFC generated a power of 2,270 nW (5.68 mW/m(2)). The proposed solvent-free air cathode paper-based MFC device could be used for environmentally-friendly energy storage as well as in single-use medical power supplies that use organic matter.

A solvent-free microbial-activated air cathode battery paper platform made with pencil-traced graphite electrodes

PubMed Central

Lee, Seung Ho; Ban, Ju Yeon; Oh, Chung-Hun; Park, Hun-Kuk; Choi, Samjin

2016-01-01

We present the fabrication of an ultra-low cost, disposable, solvent-free air cathode all-paper microbial fuel cell (MFC) that does not utilize any chemical treatments. The anode and cathode were fabricated by depositing graphite particles by drawing them on paper with a pencil (four strokes). Hydrophobic parchment paper was used as a proton exchange membrane (PEM) to allow only H+ to pass. Air cathode MFC technology, where O2 was used as an electron acceptor, was implemented on the paper platform. The bioelectric current was generated by an electrochemical process involving the redox couple of microbial-activated extracellular electron transferred electrons, PEM-passed H+, and O2 in the cathode. A fully micro-integrated pencil-traced MFC showed a fast start-time, producing current within 10 s after injection of bacterial cells. A single miniaturized all-paper air cathode MFC generated a maximum potential of 300 mV and a maximum current of 11 μA during 100 min after a single injection of Shewanella oneidensis. The micro-fabricated solvent-free air cathode all-paper MFC generated a power of 2,270 nW (5.68 mW/m2). The proposed solvent-free air cathode paper-based MFC device could be used for environmentally-friendly energy storage as well as in single-use medical power supplies that use organic matter. PMID:27333815

SoftWAXS: a computational tool for modeling wide-angle X-ray solution scattering from biomolecules.

PubMed

Bardhan, Jaydeep; Park, Sanghyun; Makowski, Lee

2009-10-01

This paper describes a computational approach to estimating wide-angle X-ray solution scattering (WAXS) from proteins, which has been implemented in a computer program called SoftWAXS. The accuracy and efficiency of SoftWAXS are analyzed for analytically solvable model problems as well as for proteins. Key features of the approach include a numerical procedure for performing the required spherical averaging and explicit representation of the solute-solvent boundary and the surface of the hydration layer. These features allow the Fourier transform of the excluded volume and hydration layer to be computed directly and with high accuracy. This approach will allow future investigation of different treatments of the electron density in the hydration shell. Numerical results illustrate the differences between this approach to modeling the excluded volume and a widely used model that treats the excluded-volume function as a sum of Gaussians representing the individual atomic excluded volumes. Comparison of the results obtained here with those from explicit-solvent molecular dynamics clarifies shortcomings inherent to the representation of solvent as a time-averaged electron-density profile. In addition, an assessment is made of how the calculated scattering patterns depend on input parameters such as the solute-atom radii, the width of the hydration shell and the hydration-layer contrast. These results suggest that obtaining predictive calculations of high-resolution WAXS patterns may require sophisticated treatments of solvent.

Structural changes in block copolymer micelles induced by cosolvent mixtures†

PubMed Central

Kelley, Elizabeth G.; Smart, Thomas P.; Jackson, Andrew J.; Sullivan, Millicent O.

2013-01-01

We investigated the influence of tetrahydrofuran (THF) addition on the structure of poly(1,2-butadiene-b-ethylene oxide) [PB-PEO] micelles in aqueous solution. Our studies showed that while the micelles remained starlike, the micelle core-corona interfacial tension and micelle size decreased upon THF addition. The detailed effects of the reduction in interfacial tension were probed using contrast variations in small angle neutron scattering (SANS) experiments. At low THF contents (high interfacial tensions), the SANS data were fit to a micelle form factor that incorporated a radial density distribution of corona chains to account for the starlike micelle profile. However, at higher THF contents (low interfacial tensions), the presence of free chains in solution affected the scattering at high q and required the implementation of a linear combination of micelle and Gaussian coil form factors. These SANS data fits indicated that the reduction in interfacial tension led to broadening of the core-corona interface, which increased the PB chain solvent accessibility at intermediate THF solvent fractions. We also noted that the micelle cores swelled with increasing THF addition, suggesting that previous assumptions of the micelle core solvent content in cosolvent mixtures may not be accurate. Control over the size, corona thickness, and extent of solvent accessible PB in these micelles can be a powerful tool in the development of targeting delivery vehicles. PMID:24282441

Structural changes in block copolymer micelles induced by cosolvent mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelley, Elizabeth G.; Smart, Thomas P.; Jackson, Andrew J.

2012-11-26

We investigated the influence of tetrahydrofuran (THF) addition on the structure of poly(1,2-butadiene-b-ethylene oxide) [PB-PEO] micelles in aqueous solution. Our studies showed that while the micelles remained starlike, the micelle core-corona interfacial tension and micelle size decreased upon THF addition. The detailed effects of the reduction in interfacial tension were probed using contrast variations in small angle neutron scattering (SANS) experiments. At low THF contents (high interfacial tensions), the SANS data were fit to a micelle form factor that incorporated a radial density distribution of corona chains to account for the starlike micelle profile. However, at higher THF contents (lowmore » interfacial tensions), the presence of free chains in solution affected the scattering at high q and required the implementation of a linear combination of micelle and Gaussian coil form factors. These SANS data fits indicated that the reduction in interfacial tension led to broadening of the core-corona interface, which increased the PB chain solvent accessibility at intermediate THF solvent fractions. We also noted that the micelle cores swelled with increasing THF addition, suggesting that previous assumptions of the micelle core solvent content in cosolvent mixtures may not be accurate. Control over the size, corona thickness, and extent of solvent accessible PB in these micelles can be a powerful tool in the development of targeting delivery vehicles.« less

A solvent-free microbial-activated air cathode battery paper platform made with pencil-traced graphite electrodes

NASA Astrophysics Data System (ADS)

Lee, Seung Ho; Ban, Ju Yeon; Oh, Chung-Hun; Park, Hun-Kuk; Choi, Samjin

2016-06-01

We present the fabrication of an ultra-low cost, disposable, solvent-free air cathode all-paper microbial fuel cell (MFC) that does not utilize any chemical treatments. The anode and cathode were fabricated by depositing graphite particles by drawing them on paper with a pencil (four strokes). Hydrophobic parchment paper was used as a proton exchange membrane (PEM) to allow only H+ to pass. Air cathode MFC technology, where O2 was used as an electron acceptor, was implemented on the paper platform. The bioelectric current was generated by an electrochemical process involving the redox couple of microbial-activated extracellular electron transferred electrons, PEM-passed H+, and O2 in the cathode. A fully micro-integrated pencil-traced MFC showed a fast start-time, producing current within 10 s after injection of bacterial cells. A single miniaturized all-paper air cathode MFC generated a maximum potential of 300 mV and a maximum current of 11 μA during 100 min after a single injection of Shewanella oneidensis. The micro-fabricated solvent-free air cathode all-paper MFC generated a power of 2,270 nW (5.68 mW/m2). The proposed solvent-free air cathode paper-based MFC device could be used for environmentally-friendly energy storage as well as in single-use medical power supplies that use organic matter.

Deep Eutectic Solvents pretreatment of agro-industrial food waste.

PubMed

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).

Solubility prediction, solvate and cocrystal screening as tools for rational crystal engineering.

PubMed

Loschen, Christoph; Klamt, Andreas

2015-06-01

The fact that novel drug candidates are becoming increasingly insoluble is a major problem of current drug development. Computational tools may address this issue by screening for suitable solvents or by identifying potential novel cocrystal formers that increase bioavailability. In contrast to other more specialized methods, the fluid phase thermodynamics approach COSMO-RS (conductor-like screening model for real solvents) allows for a comprehensive treatment of drug solubility, solvate and cocrystal formation and many other thermodynamics properties in liquids. This article gives an overview of recent COSMO-RS developments that are of interest for drug development and contains several new application examples for solubility prediction and solvate/cocrystal screening. For all property predictions COSMO-RS has been used. The basic concept of COSMO-RS consists of using the screening charge density as computed from first principles calculations in combination with fast statistical thermodynamics to compute the chemical potential of a compound in solution. The fast and accurate assessment of drug solubility and the identification of suitable solvents, solvate or cocrystal formers is nowadays possible and may be used to complement modern drug development. Efficiency is increased by avoiding costly quantum-chemical computations using a database of previously computed molecular fragments. COSMO-RS theory can be applied to a range of physico-chemical properties, which are of interest in rational crystal engineering. Most notably, in combination with experimental reference data, accurate quantitative solubility predictions in any solvent or solvent mixture are possible. Additionally, COSMO-RS can be extended to the prediction of cocrystal formation, which results in considerable predictive accuracy concerning coformer screening. In a recent variant costly quantum chemical calculations are avoided resulting in a significant speed-up and ease-of-use. © 2015 Royal Pharmaceutical Society.

Ionic Liquids and Relative Process Design

NASA Astrophysics Data System (ADS)

Zhang, S.; Lu, X.; Zhang, Y.; Zhou, Q.; Sun, J.; Han, L.; Yue, G.; Liu, X.; Cheng, W.; Li, S.

Ionic liquids have gained increasing attention in recent years due to their significant advantages, not only as alternative solvents but also as new materials and catalysts. Until now, most research work on ionic liquids has been at the laboratory or pilot scale. In view of the multifarious applications of ionic liquids, more new knowledge is needed and more systematic work on ionic liquids should be carried out deeply and broadly in order to meet the future needs of process design. For example, knowledge of the physicochemical properties is indispensable for the design of new ionic liquids and for the development of novel processes. The synthesis and application of ionic liquids are fundamental parts of engineering science, and the toxicity and environmental assessment of ionic liquids is critical importance for their large scale applications, especially for process design. These research aspects are closely correlated to the industrial applications of ionic liquids and to sustainable processes. However, material process design in the industrial applications of ionic liquids has hardly been implemented. Therefore, this chapter reviews several essential issues that are closely related to process design, such as the synthesis, structure-property relationships, important applications, and toxicity of ionic liquids.

An overview of permeable reactive barriers for in situ sustainable groundwater remediation.

PubMed

Obiri-Nyarko, Franklin; Grajales-Mesa, S Johana; Malina, Grzegorz

2014-09-01

Permeable reactive barriers (PRBs) are one of the innovative technologies widely accepted as an alternative to the 'pump and treat' (P&T) for sustainable in situ remediation of contaminated groundwater. The concept of the technology involves the emplacement of a permeable barrier containing reactive materials across the flow path of the contaminated groundwater to intercept and treat the contaminants as the plume flows through it under the influence of the natural hydraulic gradient. Since the invention of PRBs in the early 1990s, a variety of materials has been employed to remove contaminants including heavy metals, chlorinated solvents, aromatic hydrocarbons, and pesticides. Contaminant removal is usually accomplished via processes such as adsorption, precipitation, denitrification and biodegradation. Despite wide acknowledgment, there are still unresolved issues about long term-performance of PRBs, which have somewhat affected their acceptability and full-scale implementation. The current paper presents an overview of the PRB technology, which includes the state of art, the merits and limitations, the reactive media used so far, and the mechanisms employed to transform or immobilize contaminants. The paper also looks at the design, construction and the long-term performance of PRBs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Making Strategic Planning Work: Experiences from a Private University. AIR 1986 Annual Forum Paper.

ERIC Educational Resources Information Center

Chan, Susy S.

Issues in implementating strategic planning in higher education management are considered, along with successful strategies and problem areas in implementing an integrated planning and budgeting process at DePaul University, a comprehensive Catholic university. Key implementation issues are as follows: (1) maintaining an organizational balance…

Development of a methodology to compute solvation free energies on the basis of the theory of energy representation for solutions represented with a polarizable force field.

PubMed

Suzuoka, Daiki; Takahashi, Hideaki; Ishiyama, Tatsuya; Morita, Akihiro

2012-12-07

We have developed a method of molecular simulations utilizing a polarizable force field in combination with the theory of energy representation (ER) for the purpose of establishing an efficient and accurate methodology to compute solvation free energies. The standard version of the ER method is, however, based on the assumption that the solute-solvent interaction is pairwise additive for its construction. A crucial step in the present method is to introduce an intermediate state in the solvation process to treat separately the many-body interaction associated with the polarizable model. The intermediate state is chosen so that the solute-solvent interaction can be formally written in the pairwise form, though the solvent molecules are interacting with each other with polarizable charges dependent on the solvent configuration. It is, then, possible to extract the free energy contribution δμ due to the many-body interaction between solute and solvent from the total solvation free energy Δμ. It is shown that the free energy δμ can be computed by an extension of the recent development implemented in quantum mechanical∕molecular mechanical simulations. To assess the numerical robustness of the approach, we computed the solvation free energies of a water and a methanol molecule in water solvent, where two paths for the solvation processes were examined by introducing different intermediate states. The solvation free energies of a water molecule associated with the two paths were obtained as -5.3 and -5.8 kcal∕mol. Those of a methanol molecule were determined as -3.5 and -3.7 kcal∕mol. These results of the ER simulations were also compared with those computed by a numerically exact approach. It was demonstrated that the present approach produces the solvation free energies in comparable accuracies to simulations of thermodynamic integration (TI) method within a tenth of computational time used for the TI simulations.

Implementation of picoSpin Benchtop NMR Instruments into Organic Chemistry Teaching Laboratories through Spectral Analysis of Fischer Esterification Products

ERIC Educational Resources Information Center

Yearty, Kasey L.; Sharp, Joseph T.; Meehan, Emma K.; Wallace, Doyle R.; Jackson, Douglas M.; Morrison, Richard W.

2017-01-01

[Superscript 1]H NMR analysis is an important analytical technique presented in introductory organic chemistry courses. NMR instrument access is limited for undergraduate organic chemistry students due to the size of the instrument, price of NMR solvents, and the maintenance level required for instrument upkeep. The University of Georgia Chemistry…

OXIDATION OF ALKANES WITH AIR USING IRON AND MANGANESE CATALYSTS. AN OVERALL GREEN CHEMISTRY APPROACH INCLUDING THE USE OF ALTERNATIVE SOLVENT SYSTEMS GENERATED BY PARIS II

EPA Science Inventory

The selective oxidation of alkanes is an industrially important process that is often plagued by low conversions and the formation of unwanted by-products. Research being conducted at the USEPA, implements a Green chemistry approach which is utilized to improve these difficult o...

Occupational Health and the Visual Arts: An Introduction.

PubMed

Hinkamp, David; McCann, Michael; Babin, Angela R

2017-09-01

Occupational hazards in the visual arts often involve hazardous materials, though hazardous equipment and hazardous work conditions can also be found. Occupational health professionals are familiar with most of these hazards and are particularly qualified to contribute clinical and preventive expertise to these issues. Articles illustrating visual arts health issues were sought and reviewed. Literature sources included medical databases, unindexed art-health publications, and popular press articles. Few medical articles examine health issues in the visuals arts directly, but exposures to pigments, solvents, and other hazards found in the visual arts are well described. The hierarchy of controls is an appropriate model for controlling hazards and promoting safer visual art workplaces. The health and safety of those working in the visual arts can benefit from the occupational health approach. Sources of further information are available.

Investigating the structural transitions of proteins during dissolution by mass spectrometry.

PubMed

Gong, Xiaoyun; Xiong, Xingchuang; Qi, Lin; Fang, Xiang

2017-03-01

An appropriate solvent environment is essential for the implementation of biological functions of proteins. Interactions between protein residues and solvent molecules are of great importance for proteins to maintain their active structure and catalyze biochemical reactions. In this study, we investigated such interactions and studied the structural transitions of proteins during their dissolution process. Our previously developed technique, namely solvent assisted electric field induced desorption/ionization, was used for the dissolution and immediate ionization of proteins. Different solvents and proteins were involved in the investigation. According to the results, cytochrome c underwent significant unfolding during dissolution in the most commonly used NH 4 Ac buffer. The unfolding got more serious when the concentration of NH 4 Ac was further increased. Extending the dissolution time resulted in the re-folding of cytochrome c. In comparison, no unfolding was observed if cytochrome c was pre-dissolved in NH 4 Ac buffer and detected by nano-ESI. Furthermore, no unfolding was observed during the dissolution process of cytochrome c in water. Interactions between the residues of cytochrome c and the solute of NH 4 Ac might be the reason for the unfolding phenomenon. Similar unfolding phenomenon was observed on holo-myoglobin. However, the observed dissolution feature of insulin was different. No unfolding was observed on insulin during dissolution in NH 4 Ac buffers. Insulin underwent observable unfolding when water was used for dissolution. This might be due to the structural difference between different proteins. The obtained results in the present study furthered our insights into the interactions between proteins and the solvents during the phase transition of dissolution. Copyright © 2016 Elsevier B.V. All rights reserved.

Polder maps: Improving OMIT maps by excluding bulk solvent

DOE PAGES

Liebschner, Dorothee; Afonine, Pavel V.; Moriarty, Nigel W.; ...

2017-02-01

The crystallographic maps that are routinely used during the structure-solution workflow are almost always model-biased because model information is used for their calculation. As these maps are also used to validate the atomic models that result from model building and refinement, this constitutes an immediate problem: anything added to the model will manifest itself in the map and thus hinder the validation. OMIT maps are a common tool to verify the presence of atoms in the model. The simplest way to compute an OMIT map is to exclude the atoms in question from the structure, update the corresponding structure factorsmore » and compute a residual map. It is then expected that if these atoms are present in the crystal structure, the electron density for the omitted atoms will be seen as positive features in this map. This, however, is complicated by the flat bulk-solvent model which is almost universally used in modern crystallographic refinement programs. This model postulates constant electron density at any voxel of the unit-cell volume that is not occupied by the atomic model. Consequently, if the density arising from the omitted atoms is weak then the bulk-solvent model may obscure it further. A possible solution to this problem is to prevent bulk solvent from entering the selected OMIT regions, which may improve the interpretative power of residual maps. This approach is called a polder (OMIT) map. Polder OMIT maps can be particularly useful for displaying weak densities of ligands, solvent molecules, side chains, alternative conformations and residues both in terminal regions and in loops. As a result, the tools described in this manuscript have been implemented and are available in PHENIX.« less

Key Policy Issues in the Implementation of User Choice. Working Paper No. 8.

ERIC Educational Resources Information Center

Smith, Joy Selby; Smith, Chris Selby; Ferrier, Fran

This working paper examines key policy issues in the implementation of Australia's User Choice policy regarding allocating public funds for vocational education and training (VET). Part 1 explains the process used to obtain stakeholders regarding the User Choice policy, the administrative arrangements required to support it, and issues that must…

Challenges Faced by Teachers Implementing Socio-Scientific Issues as Core Elements in Their Classroom Practices

ERIC Educational Resources Information Center

Bossér, Ulrika; Lundin, Mattias; Lindahl, Mats; Linder, Cedric

2015-01-01

Teachers may face considerable challenges when implementing socio-scientific issues (SSI) in their classroom practices, such as incorporating student-centred teaching practices and exploring knowledge and values in the context of socioscientific issues. This year-long study explores teachers' reflections on the process of developing their…

Solvent-mediated nonelectrostatic ion-ion interactions predicting anomalies in electrophoresis.

PubMed

Goswami, Prakash; Dhar, Jayabrata; Ghosh, Uddipta; Chakraborty, Suman

2017-03-01

We study the effects of solvent-mediated nonelectrostatic ion-ion interactions on electrophoretic mobility of a charged spherical particle. To this end, we consider the case of low surface electrostatic potential resulting in the linearization of the governing equations, which enables us to deduce a closed-form analytical solution to the electrophoretic mobility. We subsequently compare our results to the standard model using Henry's approach and report the changes brought about by the nonelectrostatic potential. The classical approach to determine the electrophoretic mobility underpredicts the particle velocity when compared with experiments. We show that this issue can be resolved by taking into account nonelectrostatic interactions. Our analysis further reveals the phenomenon of electrophoretic mobility reversal that has been experimentally observed in numerous previous studies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Human Resource Development Issues in the Implementation of the Western China Development Strategy

ERIC Educational Resources Information Center

Xiao, Mingzheng

2007-01-01

This paper systematically illustrates the value and role of human resource development in the implementation of the Western China development strategy. It analyzes in details some current human resource issues constraining the implementation of the Western China development strategy and those on the sustainable development process of economic…

A Framework for Identifying Implementation Issues Affecting Extension Human Sciences Programming

ERIC Educational Resources Information Center

Abell, Ellen; Cummings, Rebekah; Duke, Adrienne M.; Marshall, Jennifer Wells

2015-01-01

Extension programs based on identified needs, relevant theory, and solid research too often fail to realize their objectives. Program implementation is acknowledged to contribute to program effectiveness, yet systematic attention has not been paid to the array of implementation issues that can complicate achieving program goals. We developed the…

Chemically enhanced in situ recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sale, T.; Pitts, M.; Wyatt, K.

1996-08-01

Chemically enhanced recovery is a promising alternative to current technologies for management of subsurface releases of organic liquids. Through the inclusion of surfactants, solvents, polymers, and/or alkaline agents to a waterflood, the transport of targeted organic compounds can be increased and rates of recovery enhanced. By far, the vast majority of work done in the field of chemically enhanced recovery has been at a laboratory scale. The following text focuses on chemically enhanced recovery from a field application perspective with emphasis given to chlorinated solvents in a low permeability setting. While chlorinated solvents are emphasized, issues discussed are also relevantmore » to organic liquids less dense than water such as petroleum products. Topics reviewed include: (1) Description of technology; (2) General technology considerations; (3) Low permeability media considerations; (4) Cost and reliability considerations; (5) Commercial availability; and (6) Case histories. Through this paper an appreciation is developed of both the potential and limitations of chemically enhanced recovery. Excluded from the scope of this paper is the in situ destruction of organic compounds through processes such as chemical or biological oxidation, chemically enhanced recovery of inorganic compounds, and ex situ soil treatment processes. 11 refs., 2 figs., 1 tab.« less

Stability and thermophysical studies on deep eutectic solvent based carbon nanotube nanofluid

NASA Astrophysics Data System (ADS)

Chen, Yan Yao; Walvekar, Rashmi; Khalid, Mohammad; Shahbaz, Kaveh; Gupta, T. C. S. M.

2017-07-01

Commercial coolants such as water, ethylene glycol and triethylene glycol possess very low thermal conductivity, high vapor pressure, corrosion issues and low thermal stability thus limiting the thermal enhancement of the nanofluids. Thus, a new type of base fluid known as deep eutectic solvents (DESs) is proposed in this work as a potential substitute for the conventional base fluid due to their unique solvent properties such as low vapor pressure, high thermal stability, biodegradability and non-flammability. In this work, 33 different DESs derived from phosphonium halide salt and ammonium halide salts were synthesised. Carbon nantubes (CNTs) with different concentrations (0.01 wt%-0.08 wt%) were dispersed into DESs with the help of sonication. Stability of the nanofluids were determined using both qualitative (visual observation) and quantitative (UV spectroscopy) approach. In addition, thermo-physical properties such as thermal conductivity, specific heat, viscosity and density were investigated. The stability results indicated that phosphonium based DESs have higher stability (up to 4 d) as compared to ammonium-based DESs (up to 3 d). Thermal enhancement of 30% was observed for ammonium based DES-CNT nanofluid whereas negative thermal enhancement was observed in phosphonium based DES-CNT nanofluid.

Fluorescent probe studies of polarity and solvation within room temperature ionic liquids: a review.

PubMed

Pandey, Shubha; Baker, Sheila N; Pandey, Siddharth; Baker, Gary A

2012-09-01

Ionic liquids display an array of useful and sometimes unconventional, solvent features and have attracted considerable interest in the field of green chemistry for the potential they hold to significantly reduce environmental emissions. Some of these points have a bearing on the chemical reactivity of these systems and have also generated interest in the physical and theoretical aspects of solvation in ionic liquids. This review presents an introduction to the field of ionic liquids, followed by discussion of investigations into the solvation properties of neat ionic liquids or mixed systems including ionic liquids as a major or minor component. The ionic liquid based multicomponent systems discussed are composed of other solvents, other ionic liquids, carbon dioxide, surfactants or surfactant solutions. Although we clearly focus on fluorescence spectroscopy as a tool to illuminate ionic liquid systems, the issues discussed herein are of general relevance to discussions of polarity and solvent effects in ionic liquids. Transient solvation measurements carried out by means of time-resolved fluorescence measurements are particularly powerful for their ability to parameterize the kinetics of the solvation process in ionic liquids and are discussed as well.

Single-Ion Solvation Free Energies and the Normal Hydrogen Electrode Potential in Methanol, Acetonitrile, and Dimethyl Sulfoxide

PubMed Central

Kelly, Casey P.; Cramer, Christopher J.; Truhlar, Donald G.

2008-01-01

The division of thermodynamic solvation free energies of electrolytes into ionic constituents is conventionally accomplished by using the single-ion solvation free energy of one reference ion, conventionally the proton, to set the single-ion scales. Thus the determination of the free energy of solvation of the proton in various solvents is a fundamental issue of central importance in solution chemistry. In the present article, relative solvation free energies of ions and ion-solvent clusters in methanol, acetonitrile, and dimethyl sulfoxide (DMSO) have been determined using a combination of experimental and theoretical gas-phase free energies of formation, solution-phase reduction potentials and acid dissociation constants, and gas-phase clustering free energies. Applying the cluster pair approximation to differences between these relative solvation free energies leads to values of −263.5, −260.2, and −273.3 kcal/mol for the absolute solvation free energy of the proton in methanol, acetonitrile, and DMSO, respectively. The final absolute proton solvation free energies are used to assign absolute values for the normal hydrogen electrode potential and the solvation free energies of other single ions in the above solvents. PMID:17214493

Rapid Quantification of N-Methyl-2-pyrrolidone in Polymer Matrices by Thermal Desorption-GC/MS.

PubMed

Kim, Young-Min; Kim, Jae Woo; Moon, Hye Mi; Lee, Min-Jin; Hosaka, Akihiko; Watanabe, Atsushi; Teramae, Norio; Park, Young-Kwon; Myung, Seung-Woon

2017-01-01

Analysis of a residual solvent in polymeric materials has become an important issue due to the increased regulations and standards for its use. N-Methyl-2-pyrrolidone (NMP) is a solvent widely used in many industries and restricted as one of the chemicals under EU REACH regulations due to its potential harmful effects. In this study, thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) is applied for the quantitative analysis of NMP with the use of a polymer-coated sample cup. By using the polymer-coated sample cup, the vaporization of NMP was prevented during waiting time before TD-GC/MS analysis. The calibration curve for the TD method showed good linearity (correlation coefficient, r 2 = 0.9998) and precision values (below 5.3% RSD). NMP recovery rates in different polymer matrices (PS, PMMA and PVC) were in the range of 98.8 to 106.6% with RSD values below 5.0%. The quantification result (600 mg NMP/kg PVC) for the blind NMP carrying sample in a PVC matrix by TD-GC/MS was higher than that (532 mg NMP/kg PVC) by solvent extraction-GC/MS method.

Temporal variations in parameters reflecting terminal-electron-accepting processes in an aquifer contaminated with waste fuel and chlorinated solvents

USGS Publications Warehouse

McGuire, Jennifer T.; Smith, Erik W.; Long, David T.; Hyndman, David W.; Haack, Sheridan K.; Klug, Michael J.; Velbel, Michael A.

2000-01-01

A fundamental issue in aquifer biogeochemistry is the means by which solute transport, geochemical processes, and microbiological activity combine to produce spatial and temporal variations in redox zonation. In this paper, we describe the temporal variability of TEAP conditions in shallow groundwater contaminated with both waste fuel and chlorinated solvents. TEAP parameters (including methane, dissolved iron, and dissolved hydrogen) were measured to characterize the contaminant plume over a 3-year period. We observed that concentrations of TEAP parameters changed on different time scales and appear to be related, in part, to recharge events. Changes in all TEAP parameters were observed on short time scales (months), and over a longer 3-year period. The results indicate that (1) interpretations of TEAP conditions in aquifers contaminated with a variety of organic chemicals, such as those with petroleum hydrocarbons and chlorinated solvents, must consider additional hydrogen-consuming reactions (e.g., dehalogenation); (2) interpretations must consider the roles of both in situ (at the sampling point) biogeochemical and solute transport processes; and (3) determinations of microbial communities are often necessary to confirm the interpretations made from geochemical and hydrogeological measurements on these processes.

Sacrificial component fabrication for optimised production of micro-vascular polymer composite

NASA Astrophysics Data System (ADS)

Dalton, B.; Dixon, D.; McIlhagger, A.; Archer, E.

2015-02-01

Smart functional materials are a viable future goal for advanced applications in aerospace, space and medical applications. In this work micro-vascular polymer composite systems have been developed using sacrificial fibres produced from catalyst loaded Poly(lactic acid). The sacrificial fibres have been produced via a published technique which treated PLA in a solvent catalyst mixture of 60% Trifluoroethanol, 40% H2O dispersed with 10 wt% tin (II) oxalate catalyst. A second process of polymer extrusion of PLA using graded fill contents of tin (II) oxalate has also been developed for the up scaled production of fibres as an alternative to solution treatment. Thermal analysis (TGA) was used to compare sacrificial fibre specimens. PLA fibres produced via the polymer extrusion method outperformed solution treated fibres displaying a lower degradation onset temperature (average 25°C lower), higher degradation rates (observed through a derivative curve comparison) and lower residual catalyst content (0.67% solvent treated fibre against 0.16% extruded fibre). The continuous extrusion process is solvent free and is suitable for high volume production. This work has been carried out to fully understand the fabrication issues with sacrificial components.

Extending the Solvation-Layer Interface Condition Continum Electrostatic Model to a Linearized Poisson-Boltzmann Solvent.

PubMed

Molavi Tabrizi, Amirhossein; Goossens, Spencer; Mehdizadeh Rahimi, Ali; Cooper, Christopher D; Knepley, Matthew G; Bardhan, Jaydeep P

2017-06-13

We extend the linearized Poisson-Boltzmann (LPB) continuum electrostatic model for molecular solvation to address charge-hydration asymmetry. Our new solvation-layer interface condition (SLIC)/LPB corrects for first-shell response by perturbing the traditional continuum-theory interface conditions at the protein-solvent and the Stern-layer interfaces. We also present a GPU-accelerated treecode implementation capable of simulating large proteins, and our results demonstrate that the new model exhibits significant accuracy improvements over traditional LPB models, while reducing the number of fitting parameters from dozens (atomic radii) to just five parameters, which have physical meanings related to first-shell water behavior at an uncharged interface. In particular, atom radii in the SLIC model are not optimized but uniformly scaled from their Lennard-Jones radii. Compared to explicit-solvent free-energy calculations of individual atoms in small molecules, SLIC/LPB is significantly more accurate than standard parametrizations (RMS error 0.55 kcal/mol for SLIC, compared to RMS error of 3.05 kcal/mol for standard LPB). On parametrizing the electrostatic model with a simple nonpolar component for total molecular solvation free energies, our model predicts octanol/water transfer free energies with an RMS error 1.07 kcal/mol. A more detailed assessment illustrates that standard continuum electrostatic models reproduce total charging free energies via a compensation of significant errors in atomic self-energies; this finding offers a window into improving the accuracy of Generalized-Born theories and other coarse-grained models. Most remarkably, the SLIC model also reproduces positive charging free energies for atoms in hydrophobic groups, whereas standard PB models are unable to generate positive charging free energies regardless of the parametrized radii. The GPU-accelerated solver is freely available online, as is a MATLAB implementation.

Ionic-liquid-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the forensic determination of methamphetamine in human urine.

PubMed

Wang, Ruifeng; Qi, Xiujuan; Zhao, Lei; Liu, Shimin; Gao, Shuang; Ma, Xiangyuan; Deng, Youquan

2016-07-01

Determination of methamphetamine in forensic laboratories is a major issue due to its health and social harm. In this work, a simple, sensitive, and environmentally friendly method based on ionic liquid dispersive liquid-liquid microextraction combined with high-performance liquid chromatography was established for the analysis of methamphetamine in human urine. 1-Octyl-3-methylimidazolium hexafluorophosphate with the help of disperser solvent methanol was selected as the microextraction solvent in this process. Various parameters affecting the extraction efficiency of methamphetamine were investigated systemically, including extraction solvent and its volume, disperser solvent and its volume, sample pH, extraction temperature, and centrifugal time. Under the optimized conditions, a good linearity was obtained in the concentration range of 10-1000 ng/mL with determination coefficient >0.99. The limit of detection calculated at a signal-to-noise ratio of 3 was 1.7 ng/mL and the relative standard deviations for six replicate experiments at three different concentration levels of 100, 500, and 1000 ng/mL were 6.4, 4.5, and 4.7%, respectively. Meanwhile, up to 220-fold enrichment factor of methamphetamine and acceptable extraction recovery (>80.0%) could be achieved. Furthermore, this method has been successfully employed for the sensitive detection of a urine sample from a suspected drug abuser. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

US federal cocaine essential (‘precursor’) chemical regulation impacts on US cocaine availability: an intervention time–series analysis with temporal replication

PubMed Central

Callaghan, Russell C.; Liu, Lon‐Mu

2015-01-01

Abstract Background and Aims Research shows that essential/precursor chemical controls have had substantial impacts on US methamphetamine and heroin availability. This study examines whether US federal essential chemical regulations have impacted US cocaine seizure amount, price and purity—indicators of cocaine availability. Design Autoregressive integrated moving average (ARIMA)‐intervention time–series analysis was used to assess the impacts of four US regulations targeting cocaine manufacturing chemicals: potassium permanganate/selected solvents, implemented October 1989 sulfuric acid/hydrochloric acid, implemented October 1992; methyl isobutyl ketone, implemented May 1995; and sodium permanganate, implemented December 2006. Of these chemicals, potassium permanganate and sodium permanganate are the most critical to cocaine production. Setting Conterminous United States (January 1987—April 2011). Measurements Monthly time–series: purity‐adjusted cocaine seizure amount (in gross weight seizures < 6000 grams), purity‐adjusted price (all available seizures), and purity (all available seizures). Data source: System to Retrieve Information from Drug Evidence. Findings The 1989 potassium permanganate/solvents regulation was associated with a seizure amount decrease (change in series level) of 28% (P < 0.05), a 36% increase in price (P < 0.05) and a 4% decrease in purity (P < 0.05). Availability recovered in 1–2 years. The 2006 potassium permanganate regulation was associated with a 22% seizure amount decrease (P < 0.05), 100% price increase (P < 0.05) and 35% purity decrease (P < 0.05). Following the 2006 regulation, essentially no recovery occurred to April 2011. The other two chemical regulations were associated with statistically significant but lesser declines in indicated availability. Conclusions In the United States, essential chemical controls from 1989 to 2006 were associated with pronounced downturns in cocaine availability. PMID:25559418

US federal cocaine essential ('precursor') chemical regulation impacts on US cocaine availability: an intervention time-series analysis with temporal replication.

PubMed

Cunningham, James K; Callaghan, Russell C; Liu, Lon-Mu

2015-05-01

Research shows that essential/precursor chemical controls have had substantial impacts on US methamphetamine and heroin availability. This study examines whether US federal essential chemical regulations have impacted US cocaine seizure amount, price and purity-indicators of cocaine availability. Autoregressive integrated moving average (ARIMA)-intervention time-series analysis was used to assess the impacts of four US regulations targeting cocaine manufacturing chemicals: potassium permanganate/selected solvents, implemented October 1989 sulfuric acid/hydrochloric acid, implemented October 1992; methyl isobutyl ketone, implemented May 1995; and sodium permanganate, implemented December 2006. Of these chemicals, potassium permanganate and sodium permanganate are the most critical to cocaine production. Conterminous United States (January 1987-April 2011). Monthly time-series: purity-adjusted cocaine seizure amount (in gross weight seizures < 6000 grams), purity-adjusted price (all available seizures), and purity (all available seizures). System to Retrieve Information from Drug Evidence. The 1989 potassium permanganate/solvents regulation was associated with a seizure amount decrease (change in series level) of 28% (P < 0.05), a 36% increase in price (P < 0.05) and a 4% decrease in purity (P < 0.05). Availability recovered in 1-2 years. The 2006 potassium permanganate regulation was associated with a 22% seizure amount decrease (P < 0.05), 100% price increase (P < 0.05) and 35% purity decrease (P < 0.05). Following the 2006 regulation, essentially no recovery occurred to April 2011. The other two chemical regulations were associated with statistically significant but lesser declines in indicated availability. In the United States, essential chemical controls from 1989 to 2006 were associated with pronounced downturns in cocaine availability. © 2015 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.

In-situ medical simulation for pre-implementation testing of clinical service in a regional hospital in Hong Kong.

PubMed

Chen, P P; Tsui, N Tk; Fung, A Sw; Chiu, A Hf; Wong, W Cw; Leong, H T; Lee, P Sf; Lau, J Yw

2017-08-01

The implementation of a new clinical service is associated with anxiety and challenges that may prevent smooth and safe execution of the service. Unexpected issues may not be apparent until the actual clinical service commences. We present a novel approach to test the new clinical setting before actual implementation of our endovascular aortic repair service. In-situ simulation at the new clinical location would enable identification of potential process and system issues prior to implementation of the service. After preliminary planning, a simulation test utilising a case scenario with actual simulation of the entire care process was carried out to identify any logistic, equipment, settings or clinical workflow issues, and to trial a contingency plan for a surgical complication. All patient care including anaesthetic, surgical, and nursing procedures and processes were simulated and tested. Overall, 17 vital process and system issues were identified during the simulation as potential clinical concerns. They included difficult patient positioning, draping pattern, unsatisfactory equipment setup, inadequate critical surgical instruments, blood products logistics, and inadequate nursing support during crisis. In-situ simulation provides an innovative method to identify critical deficiencies and unexpected issues before implementation of a new clinical service. Life-threatening and serious practical issues can be identified and corrected before formal service commences. This article describes our experience with the use of simulation in pre-implementation testing of a clinical process or service. We found the method useful and would recommend it to others.

Routine Microsecond Molecular Dynamics Simulations with AMBER on GPUs. 2. Explicit Solvent Particle Mesh Ewald.

PubMed

Salomon-Ferrer, Romelia; Götz, Andreas W; Poole, Duncan; Le Grand, Scott; Walker, Ross C

2013-09-10

We present an implementation of explicit solvent all atom classical molecular dynamics (MD) within the AMBER program package that runs entirely on CUDA-enabled GPUs. First released publicly in April 2010 as part of version 11 of the AMBER MD package and further improved and optimized over the last two years, this implementation supports the three most widely used statistical mechanical ensembles (NVE, NVT, and NPT), uses particle mesh Ewald (PME) for the long-range electrostatics, and runs entirely on CUDA-enabled NVIDIA graphics processing units (GPUs), providing results that are statistically indistinguishable from the traditional CPU version of the software and with performance that exceeds that achievable by the CPU version of AMBER software running on all conventional CPU-based clusters and supercomputers. We briefly discuss three different precision models developed specifically for this work (SPDP, SPFP, and DPDP) and highlight the technical details of the approach as it extends beyond previously reported work [Götz et al., J. Chem. Theory Comput. 2012, DOI: 10.1021/ct200909j; Le Grand et al., Comp. Phys. Comm. 2013, DOI: 10.1016/j.cpc.2012.09.022].We highlight the substantial improvements in performance that are seen over traditional CPU-only machines and provide validation of our implementation and precision models. We also provide evidence supporting our decision to deprecate the previously described fully single precision (SPSP) model from the latest release of the AMBER software package.

Mass Transfer And Hydraulic Testing Of The V-05 And V-10 Contactors With The Next Generation Solvent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herman, D. T.; Duignan, M. R.; Williams, M. R.

The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent. To support this integration of NGS into the MCU facilities, Savannah River Remediation (SRR) requested that Savannah River National Laboratory (SRNL) perform 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 differs from prior testing by utilizing a blend of BOBCalixC6 based solvent and the NGS with the full (0.05more » M) concentration of the 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 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. Stage efficiency and mass distribution ratios were determined by measuring Cs concentration in the aqueous and organic phases during single contactor testing. The nominal cesium distribution ratio, D(Cs) measured for extraction ranged from 37-60. The data showed greater than 96% stage efficiency for extraction. No significant differences were noted for operations at 4, 8 or 12 gpm aqueous salt simulant feed flow rates. The first scrub test (contact with weak caustic solution) yielded average scrub D(Cs) values of 3.3 to 5.2 and the second scrub test produced an average value of 1.8 to 2.3. For stripping behavior, the “first stage” D Cs) values ranged from 0.04 to 0.08. The efficiency of the low flow (0.27 gpm aqueous) was calculated to be 82.7%. The Spreadsheet Algorithm for Stagewise Solvent Extraction (SASSE) predicted equivalent DF for MCU from this testing is greater than 3,500 assuming 95% efficiency during extraction and 80% efficiency during scrub and strip. Hydraulically, the system performed very well in all tests. Target flows were easily obtained and stable throughout testing. Though some issues were encountered with plugging in the coalescer, they were not related to the solvent. No hydraulic upsets due to the solvent were experienced during any of the tests conducted. The first extraction coalescer element used in testing developed high pressure drop that made it difficult to maintain the target flow rates. Analysis showed an accumulation of sodium aluminosilicate solids. The coalescer was replaced with one from the same manufacturer’s lot and pressure drop was no longer an issue. Concentrations of Isopar™ L and Modifier were measured using semi-volatile organic analysis (SVOA) and high performance liquid chromatography (HPLC) to determine the amount of solvent carryover. For low-flow (0.27 gpm aqueous) conditions in stripping, SVOA measured the Isopar™ L post-contactor concentration to be 25 mg/L, HPLC measured 39 mg/L of Modifier. For moderate-flow (0.54 gpm aqueous) conditions, SVOA measured the Isopar™ L postcontactor to be ~69 mg/L, while the HPLC measured 56 mg/L for Modifier. For high-flow (0.8 gpm aqueous) conditions, SVOA measured the Isopar™ L post-contactor to be 39 mg/L. The post-coalescer (pre-decanter) measurements by SVOA for Isopar™ L were all less than the analysis detection limit of 10 mg/L. The HPLC measured 18, 22 and 20 mg/L Modifier for the low, medium, and high-low rates respectively. In extraction, the quantity of pre-coalescer Isopar™ L carryover measured by SVOA was ~280-410 mg/L at low flow (4 gpm aqueous), ~400-450 mg/L at moderate flow (8 gpm aqueous), and ~480 mg/L at high flow (12 gpm aqueous). The amount of post coalescer (pre-decanter) Isopar™ L carryover measured by SVOA was less than 45 mg/L for all flow rates. HPLC results for Modifier were 182, 217 and 222 mg/L for the post-contactor low, medium and high flow rates. The post-coalescer (pre-decanter) samples were measured to contain 12, 10 and 22 mg/L Modifier for the low, medium, and high flow rates. The carryover results and droplet size measurements were used to determine the decanter performance utilizing the decanter model developed by the ARES Corporation. Results show for the targeted salt flow rate of approximately 8 gpm, that over 93% of the solvent carryover from stripping is predicted to be recovered and over 96% solvent carryover from extraction is predicted to be recovered. This translates to a predicted solvent carryover of <3 ppm from stripping and <20 ppm solvent carryover from extraction. This projected performance at MCU is expected to be well within the operating limits and the historical performance for the baseline BOBCalixC6 based solvent. Droplet-size data obtained by MicroTrac™ S3400 analyzer consistently shows that the droplet size post-oalescer is significantly greater than the post-contactor or pre-coalescer samples. Increased flow rates did not show a consistent impact to the droplet size results. For the extraction testing, droplet size analysis showed that the post-contactor and pre-coalescer samples were essentially the same. The mean droplet sizes post-coalescer were less than the mean droplet sizes pre-coalescer with a very slight upward trend in the mean droplet size as the flow rate was increased. This result is probably due to the method of sampling. The larger post-coalescer drops immediately rise to the surface after leaving the coalescer element. The downstream sampling point was horizontally in-line with the element and therefore would only capture those organic droplets well mixed in the flowing aqueous stream.« less

Measuring Fidelity of Implementation--Methodological and Conceptual Issues and Challenges. CRESST Report 811

ERIC Educational Resources Information Center

Osmundson, Ellen; Herman, Joan; Ringstaff, Cathy; Dai, Yunyun; Timms, Mike

2012-01-01

A central challenge in efficacy studies centers on the issue of "fidelity of implementation," that is, the extent to which participants use the curriculum specified by curriculum developers. In this study, we describe and discuss a "fidelity of implementation" model using multiple methods and instruments to compare two versions of a science…

77 FR 44441 - Swap Transaction Compliance and Implementation Schedule: Clearing Requirement Under Section 2(h...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-30

... implementing Title VII, the Commission should focus first on systemic risk issues and then issues relating to... implementation of the Clearing Requirement will serve to reduce systemic risk by mitigating counterparty credit... non-financial end-users because they do not pose systemic risk, and, therefore, should be given the...

Moving from Good Ideas in Educational Systems Change to Sustainable Program Implementation: Coming to Terms with Some of the Realities

ERIC Educational Resources Information Center

Noell, George H.; Gansle, Kristin A.

2009-01-01

Proponents of systemic changes in education commonly encounter ethical, theoretical, and pragmatic challenges in moving from possibility to implementation of their vision of change. Although ethical and theoretical issues are critically important to a successful change initiative, pragmatic issues relevant to assuring program implementation have…

Use of Nucleic Acid-Based Tools for Monitoring Biostimulation and Bioaugmentation

DTIC Science & Technology

2011-01-01

dechlorination is a promising process for biodegradation of chlorinated solvents. The successful field evaluation and implementation of the reductive...These specialized bacteria use the chlorinated ethenes as electron acceptors and gain energy for growth from the reductive dechlorination reactions...protocol addresses the use of MBTs to quantitatively assess the Dhc population at chlorinated ethene sites and aims at providing guidance to evaluate

Contamination Control and Hardware Processing Solutions at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Burns, DeWitt H.; Hampton, Tammy; Huey, LaQuieta; Mitchell, Mark; Norwood, Joey; Lowrey, Nikki

2012-01-01

The Contamination Control Team of Marshall Space Flight Center's Materials and Processes Laboratory supports many Programs/ Projects that design, manufacture, and test a wide range of hardware types that are sensitive to contamination and foreign object damage (FOD). Examples where contamination/FOD concerns arise include sensitive structural bondline failure, critical orifice blockage, seal leakage, and reactive fluid compatibility (liquid oxygen, hydrazine) as well as performance degradation of sensitive instruments or spacecraft surfaces such as optical elements and thermal control systems. During the design phase, determination of the sensitivity of a hardware system to different types or levels of contamination/FOD is essential. A contamination control and FOD control plan must then be developed and implemented through all phases of ground processing, and, sometimes, on-orbit use, recovery, and refurbishment. Implementation of proper controls prevents cost and schedule impacts due to hardware damage or rework and helps assure mission success. Current capabilities are being used to support recent and on-going activities for multiple Mission Directorates / Programs such as International Space Station (ISS), James Webb Space Telescope (JWST), Space Launch System (SLS) elements (tanks, engines, booster), etc. The team also advances Green Technology initiatives and addresses materials obsolescence issues for NASA and external customers, most notably in the area of solvent replacement (e.g. aqueous cleaners containing hexavalent chrome, ozone depleting chemicals (CFC s and HCFC's), suspect carcinogens). The team evaluates new surface cleanliness inspection and cleaning technologies (e.g. plasma cleaning), and maintains databases for processing support materials as well as outgassing and optical compatibility test results for spaceflight environments.

Development of a Topical Resveratrol Formulation for Commercial Applications Using Dendrimer Nanotechnology.

PubMed

Pentek, Tyler; Newenhouse, Eric; O'Brien, Brennin; Chauhan, Abhay Singh

2017-01-14

Resveratrol (RSV) is well known for its anti-oxidant and anti-aging properties. However, resveratrol is insoluble in water and has stability issues. Recently, efforts were placed to prepare a resveratrol-based advanced anti-aging topical product but it contains harsh organic solvents and oils that could be harmful to the human body and the environment. Hence, we propose the use of a multifunctional dendrimer to solve the solubility and stability issues of resveratrol. A dendrimer-resveratrol complex was prepared, optimized and tested for solubility enhancement, stability in solution and cream dosage forms. We have also developed a high performance liquid chromatography method to measure the resveratrol within the final product. PAMAM dendrimers increased the solubility and stability of resveratrol in water and semisolid dosage forms. Therefore, this product would be water based 'green' formulation devoid of harsh organic solvents and oils and can be safely applied to the skin. Additionally, we have shown that the dendrimer helped to increase overall RSV loading and skin penetration of resveratrol. The dendrimer-RSV formulation was successfully scaled up towards commercialization. Dendrimer with RSV has led to an innovation in anti-aging cream and solutions that could be commercially marketed. Dendrimer-RSV complex could also be added to other product forms for additional purposes and applications.

Application of Radiation Chemistry to Some Selected Technological Issues Related to the Development of Nuclear Energy.

PubMed

Bobrowski, Krzysztof; Skotnicki, Konrad; Szreder, Tomasz

2016-10-01

The most important contributions of radiation chemistry to some selected technological issues related to water-cooled reactors, reprocessing of spent nuclear fuel and high-level radioactive wastes, and fuel evolution during final radioactive waste disposal are highlighted. Chemical reactions occurring at the operating temperatures and pressures of reactors and involving primary transients and stable products from water radiolysis are presented and discussed in terms of the kinetic parameters and radiation chemical yields. The knowledge of these parameters is essential since they serve as input data to the models of water radiolysis in the primary loop of light water reactors and super critical water reactors. Selected features of water radiolysis in heterogeneous systems, such as aqueous nanoparticle suspensions and slurries, ceramic oxides surfaces, nanoporous, and cement-based materials, are discussed. They are of particular concern in the primary cooling loops in nuclear reactors and long-term storage of nuclear waste in geological repositories. This also includes radiation-induced processes related to corrosion of cladding materials and copper-coated iron canisters, dissolution of spent nuclear fuel, and changes of bentonite clays properties. Radiation-induced processes affecting stability of solvents and solvent extraction ligands as well oxidation states of actinide metal ions during recycling of the spent nuclear fuel are also briefly summarized.

Membrane separation for non-aqueous solution

NASA Astrophysics Data System (ADS)

Widodo, S.; Khoiruddin; Ariono, D.; Subagjo; Wenten, I. G.

2018-01-01

Membrane technology has been widely used in a number of applications competing with conventional technologies in various ways. Despite the enormous applications, they are mainly used for the aqueous system. The use of membrane-based processes in a non-aqueous system is an emerging area. This is because developed membranes are still limited in separations involving aqueous solution which show several drawbacks when implemented in a non-aqueous system. The purpose of this paper is to provide a review of the current application of membrane processes in non-aqueous solutions, such as mineral oil treatment, vegetable oil processing, and organic solvent recovery. Developments of advanced membrane materials for the non-aqueous solutions such as super-hydrophobic and organic solvent resistant membranes are reviewed. In addition, challenges and future outlook of membrane separation for the non-aqueous solution are discussed.

Development status of the life marker chip instrument for ExoMars

NASA Astrophysics Data System (ADS)

Sims, Mark R.; Cullen, David C.; Rix, Catherine S.; Buckley, Alan; Derveni, Mariliza; Evans, Daniel; Miguel García-Con, Luis; Rhodes, Andrew; Rato, Carla C.; Stefinovic, Marijan; Sephton, Mark A.; Court, Richard W.; Bulloch, Christopher; Kitchingman, Ian; Ali, Zeshan; Pullan, Derek; Holt, John; Blake, Oliver; Sykes, Jonathan; Samara-Ratna, Piyal; Canali, Massimiliano; Borst, Guus; Leeuwis, Henk; Prak, Albert; Norfini, Aleandro; Geraci, Ennio; Tavanti, Marco; Brucato, John; Holm, Nils

2012-11-01

The Life Marker Chip (LMC) is one of the instruments being developed for possible flight on the 2018 ExoMars mission. The instrument uses solvents to extract organic compounds from samples of martian regolith and to transfer the extracts to dedicated detectors based around the use of antibodies. The scientific aims of the instrument are to detect organics in the form of biomarkers that might be associated with extinct life, extant life or abiotic sources of organics. The instrument relies on a novel surfactant-based solvent system and bespoke, commercial and research-developed antibodies against a number of distinct biomarkers or molecular types. The LMC comprises of a number of subsystems designed to accept up to four discrete samples of martian regolith or crushed rock, implement the solvent extraction, perform microfluidic-based multiplexed antibody-assays for biomarkers and other targets, optically detect the fluorescent output of the assays, control the internal instrument pressure and temperature, in addition to the associated instrument control electronics and software. The principle of operation, the design and the instrument development status as of December 2011 are reported here. The instrument principle can be extended to other configurations and missions as needed.

Voltammetric Perspectives on the Acidity Scale and H+/H2 Process in Ionic Liquid Media.

PubMed

Bentley, Cameron L; Bond, Alan M; Zhang, Jie

2018-03-19

Nonhaloaluminate ionic liquids (ILs) have received considerable attention as alternatives to molecular solvents in diverse applications spanning the fields of physical, chemical, and biological science. One important and often overlooked aspect of the implementation of these designer solvents is how the properties of the IL formulation affect (electro)chemical reactivity. This aspect is emphasized herein, where recent (voltammetric) studies on the energetics of proton (H + ) transfer and electrode reaction mechanisms of the H + H 2 process in IL media are highlighted and discussed. The energetics of proton transfer, quantified using the pK 3 a (minus logarithm of acidity equilibrium constant, K a ) formalism, is strongly governed by the constituent IL anion, and to a lesser extent, the IL cation. The H + /H 2 process, a model inner-sphere reaction, also displays electrochemical characteristics that are strongly IL-dependent. Overall, these studies highlight the need to carry out systematic investigations to resolve IL structure and function relationships in order to realize the potential of these diverse and versatile solvents. Expected final online publication date for the Annual Review of Analytical Chemistry Volume 11 is June 12, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Conversion and Extraction of Insoluble Organic Materials in Meteorites

NASA Technical Reports Server (NTRS)

Locke, Darren R.; Burton, Aaron S.; Niles, Paul B.

2016-01-01

We endeavor to develop and implement methods in our laboratory to convert and extract insoluble organic materials (IOM) from low car-bon bearing meteorites (such as ordinary chondrites) and Precambrian terrestrial rocks for the purpose of determining IOM structure and prebiotic chemistries preserved in these types of samples. The general scheme of converting and extracting IOM in samples is summarized in Figure 1. First, powdered samples are solvent extracted in a micro-Soxhlet apparatus multiple times using solvents ranging from non-polar to polar (hexane - non-polar, dichloromethane - non-polar to polar, methanol - polar protic, and acetonitrile - polar aprotic). Second, solid residue from solvent extractions is processed using strong acids, hydrochloric and hydrofluoric, to dissolve minerals and isolate IOM. Third, the isolated IOM is subjected to both thermal (pyrolysis) and chemical (oxidation) degradation to release compounds from the macromolecular material. Finally, products from oxidation and pyrolysis are analyzed by gas chromatography - mass spectrometry (GCMS). We are working toward an integrated method and analysis scheme that will allow us to determine prebiotic chemistries in ordinary chondrites and Precambrian terrestrial rocks. Powerful techniques that we are including are stepwise, flash, and gradual pyrolysis and ruthenium tetroxide oxidation. More details of the integrated scheme will be presented.

Non-Aqueous Titration Method for Determining Suppressor Concentration in the MCU Next Generation Solvent (NGS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor-Pashow, Kathryn M. L.; Jones, Daniel H.

A non-aqueous titration method has been used for quantifying the suppressor concentration in the MCU solvent hold tank (SHT) monthly samples since the Next Generation Solvent (NGS) was implemented in 2013. The titration method measures the concentration of the NGS suppressor (TiDG) as well as the residual tri-n-octylamine (TOA) that is a carryover from the previous solvent. As the TOA concentration has decreased over time, it has become difficult to resolve the TiDG equivalence point as the TOA equivalence point has moved closer. In recent samples, the TiDG equivalence point could not be resolved, and therefore, the TiDG concentration wasmore » determined by subtracting the TOA concentration as measured by semi-volatile organic analysis (SVOA) from the total base concentration as measured by titration. In order to improve the titration method so that the TiDG concentration can be measured directly, without the need for the SVOA data, a new method has been developed that involves spiking of the sample with additional TOA to further separate the two equivalence points in the titration. This method has been demonstrated on four recent SHT samples and comparison to results obtained using the SVOA TOA subtraction method shows good agreement. Therefore, it is recommended that the titration procedure be revised to include the TOA spike addition, and this to become the primary method for quantifying the TiDG.« less

Replacement of HCFC-225 Solvent for Cleaning NASA Propulsion Oxygen Systems

NASA Technical Reports Server (NTRS)

Mitchell, Mark A.; Lowrey, Nikki M.

2015-01-01

Since the 1990's, when the Class I Ozone Depleting Substance (ODS) chlorofluorocarbon-113 (CFC-113) was banned, NASA's rocket propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have relied upon hydrochlorofluorocarbon-225 (HCFC-225) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of HCFC-225, a Class II ODS, was prohibited by the Clean Air Act. In 2012 through 2014, leveraging resources from both the NASA Rocket Propulsion Test Program and the Defense Logistics Agency - Aviation Hazardous Minimization and Green Products Branch, test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility (WSTF) collaborated to seek out, test, and qualify a replacement for HCFC-225 that is both an effective cleaner and safe for use with oxygen systems. Candidate solvents were selected and a test plan was developed following the guidelines of ASTM G127, Standard Guide for the Selection of Cleaning Agents for Oxygen Systems. Solvents were evaluated for materials compatibility, oxygen compatibility, cleaning effectiveness, and suitability for use in cleanliness verification and field cleaning operations. Two solvents were determined to be acceptable for cleaning oxygen systems and one was chosen for implementation at NASA's rocket propulsion test facilities. The test program and results are summarized. This project also demonstrated the benefits of cross-agency collaboration in a time of limited resources.

Replacement of Hydrochlorofluorocarbon (HCFC) -225 Solvent for Cleaning and Verification Sampling of NASA Propulsion Oxygen Systems Hardware, Ground Support Equipment, and Associated Test Systems

NASA Technical Reports Server (NTRS)

Mitchell, Mark A.; Lowrey, Nikki M.

2015-01-01

Since the 1990's, when the Class I Ozone Depleting Substance (ODS) chlorofluorocarbon-113 (CFC-113) was banned, NASA's rocket propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have relied upon hydrochlorofluorocarbon-225 (HCFC-225) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of HCFC-225, a Class II ODS, was prohibited by the Clean Air Act. In 2012 through 2014, leveraging resources from both the NASA Rocket Propulsion Test Program and the Defense Logistics Agency - Aviation Hazardous Minimization and Green Products Branch, test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility (WSTF) collaborated to seek out, test, and qualify a replacement for HCFC-225 that is both an effective cleaner and safe for use with oxygen systems. Candidate solvents were selected and a test plan was developed following the guidelines of ASTM G127, Standard Guide for the Selection of Cleaning Agents for Oxygen Systems. Solvents were evaluated for materials compatibility, oxygen compatibility, cleaning effectiveness, and suitability for use in cleanliness verification and field cleaning operations. Two solvents were determined to be acceptable for cleaning oxygen systems and one was chosen for implementation at NASA's rocket propulsion test facilities. The test program and results are summarized. This project also demonstrated the benefits of cross-agency collaboration in a time of limited resources.

Formalism for calculation of polymer-solvent-mediated potential

NASA Astrophysics Data System (ADS)

Zhou, Shiqi

2006-07-01

A simple theoretical approach is proposed for calculation of a solvent-mediated potential (SMP) between two colloid particles immersed in a polymer solvent bath in which the polymer is modeled as a chain with intramolecular degrees of freedom. The present recipe is only concerned with the estimation of the density profile of a polymer site around a single solute colloid particle instead of two solute colloid particles separated by a varying distance as done in existing calculational methods for polymer-SMP. Therefore the present recipe is far simpler for numerical implementation than the existing methods. The resultant predictions for the polymer-SMP and polymer solvent-mediated mean force (polymer-SMMF) are in very good agreement with available simulation data. With the present recipe, change tendencies of the contact value and second virial coefficiency of the SMP as a function of size ratio between the colloid particle and polymer site, the number of sites per chain, and the polymer concentration are investigated in detail. The metastable critical polymer concentration as a function of size ratio and the number of sites per chain is also reported for the first time. To yield the numerical solution of the present recipe at less than 1min on a personal computer, a rapid and accurate algorithm for the numerical solution of the classical density functional theory is proposed to supply rapid and accurate estimation of the density profile of the polymer site as an input into the present formalism.

Optimization of extraction parameters of pentacyclic triterpenoids from Swertia chirata stem using response surface methodology.

PubMed

Pandey, Devendra Kumar; Kaur, Prabhjot

2018-03-01

In the present investigation, pentacyclic triterpenoids were extracted from different parts of Swertia chirata by solid-liquid reflux extraction methods. The total pentacyclic triterpenoids (UA, OA, and BA) in extracted samples were determined by HPTLC method. Preliminary studies showed that stem part contains the maximum pentacyclic triterpenoid and was chosen for further studies. Response surface methodology (RSM) has been employed successfully by solid-liquid reflux extraction methods for the optimization of different extraction variables viz., temperature ( X 1 35-70 °C), extraction time ( X 2 30-60 min), solvent composition ( X 3 20-80%), solvent-to-solid ratio ( X 4 30-60 mlg -1 ), and particle size ( X 5 3-6 mm) on maximum recovery of triterpenoid from stem parts of Swertia chirata . A Plackett-Burman design has been used initially to screen out the three extraction factors viz., particle size, temperature, and solvent composition on yield of triterpenoid. Moreover, central composite design (CCD) was implemented to optimize the significant extraction parameters for maximum triterpenoid yield. Three extraction parameters viz., mean particle size (3 mm), temperature (65 °C), and methanol-ethyl acetate solvent composition (45%) can be considered as significant for the better yield of triterpenoid A second-order polynomial model satisfactorily fitted the experimental data with the R 2 values of 0.98 for the triterpenoid yield ( p  < 0.001), implying good agreement between the experimental triterpenoid yield (3.71%) to the predicted value (3.79%).

Architectural Optimization of Digital Libraries

NASA Technical Reports Server (NTRS)

Biser, Aileen O.

1998-01-01

This work investigates performance and scaling issues relevant to large scale distributed digital libraries. Presently, performance and scaling studies focus on specific implementations of production or prototype digital libraries. Although useful information is gained to aid these designers and other researchers with insights to performance and scaling issues, the broader issues relevant to very large scale distributed libraries are not addressed. Specifically, no current studies look at the extreme or worst case possibilities in digital library implementations. A survey of digital library research issues is presented. Scaling and performance issues are mentioned frequently in the digital library literature but are generally not the focus of much of the current research. In this thesis a model for a Generic Distributed Digital Library (GDDL) and nine cases of typical user activities are defined. This model is used to facilitate some basic analysis of scaling issues. Specifically, the calculation of Internet traffic generated for different configurations of the study parameters and an estimate of the future bandwidth needed for a large scale distributed digital library implementation. This analysis demonstrates the potential impact a future distributed digital library implementation would have on the Internet traffic load and raises questions concerning the architecture decisions being made for future distributed digital library designs.

Ionic-liquid materials for the electrochemical challenges of the future.

PubMed

Armand, Michel; Endres, Frank; MacFarlane, Douglas R; Ohno, Hiroyuki; Scrosati, Bruno

2009-08-01

Ionic liquids are room-temperature molten salts, composed mostly of organic ions that may undergo almost unlimited structural variations. This review covers the newest aspects of ionic liquids in applications where their ion conductivity is exploited; as electrochemical solvents for metal/semiconductor electrodeposition, and as batteries and fuel cells where conventional media, organic solvents (in batteries) or water (in polymer-electrolyte-membrane fuel cells), fail. Biology and biomimetic processes in ionic liquids are also discussed. In these decidedly different materials, some enzymes show activity that is not exhibited in more traditional systems, creating huge potential for bioinspired catalysis and biofuel cells. Our goal in this review is to survey the recent key developments and issues within ionic-liquid research in these areas. As well as informing materials scientists, we hope to generate interest in the wider community and encourage others to make use of ionic liquids in tackling scientific challenges.

Ionic-liquid materials for the electrochemical challenges of the future

NASA Astrophysics Data System (ADS)

Armand, Michel; Endres, Frank; Macfarlane, Douglas R.; Ohno, Hiroyuki; Scrosati, Bruno

2009-08-01

Ionic liquids are room-temperature molten salts, composed mostly of organic ions that may undergo almost unlimited structural variations. This review covers the newest aspects of ionic liquids in applications where their ion conductivity is exploited; as electrochemical solvents for metal/semiconductor electrodeposition, and as batteries and fuel cells where conventional media, organic solvents (in batteries) or water (in polymer-electrolyte-membrane fuel cells), fail. Biology and biomimetic processes in ionic liquids are also discussed. In these decidedly different materials, some enzymes show activity that is not exhibited in more traditional systems, creating huge potential for bioinspired catalysis and biofuel cells. Our goal in this review is to survey the recent key developments and issues within ionic-liquid research in these areas. As well as informing materials scientists, we hope to generate interest in the wider community and encourage others to make use of ionic liquids in tackling scientific challenges.

The electrodeposition of silver composites using deep eutectic solvents.

PubMed

Abbott, Andrew P; El Ttaib, Khalid; Frisch, Gero; Ryder, Karl S; Weston, David

2012-02-21

Silver is an important metal for electronic connectors, however, it is extremely soft and wear can be a significant issue. This paper describes how improved wear resistant silver coatings can be obtained from the electrolytic deposition of silver from a solution of AgCl in an ethylene glycol/choline chloride based Deep Eutectic Solvent. An up to 10-fold decrease in the wear volume is observed by the incorporation of SiC or Al(2)O(3) particles. The work also addresses the fundamental aspect of speciation of silver chloride in solution using EXAFS to probe solution structure. The size but not the nature of the composite particles is seen to change the morphology and grain size of the silver deposit. Grain sizes are shown to be consistent with previous nucleation studies. The addition of LiF is found to significantly affect the deposit morphology and improve wear resistance.

Selective dissolution of halide perovskites as a step towards recycling solar cells

NASA Astrophysics Data System (ADS)

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

2016-05-01

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

The Use of Kits in the Analysis of Tissue Lipids Requires Validation.

PubMed

Rider, T; LeBoeuf, R C; Tso, Patrick; Jandacek, R J

2016-04-01

The ready availability and ease of use of kits for the measurement of serum lipids has greatly facilitated these measurements. In many cases it would be convenient to use these kits in the determination of lipid concentrations in tissues. The successful application of serum kits in tissue analysis requires that two important issues be considered. First, the solvent system for the extraction of the lipids and the solvent used for analysis by the kit must be compatible with the reactions in the kit. Second, the concentration range in the analyzed solution must be within the range for which the kit is used. We report here that lipids in liver and adipose tissues may be significantly underestimated by the use of some kits. We recommend that the use of kits for tissue analysis of lipids be validated for the specific analysis.

Selective dissolution of halide perovskites as a step towards recycling solar cells.

PubMed

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

2016-05-23

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb(2+) cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

Reduction of hysteresis in solution-processed InGaZnO thin-film transistors through uni-directional pre-annealing

NASA Astrophysics Data System (ADS)

Kim, Young-Rae; Kwon, Jin-Hyuk; Vincent, Premkumar; Kim, Do-Kyung; Jeong, Hyeon-Seok; Hahn, Joonku; Bae, Jin-Hyuk; Park, Jaehoon

2018-01-01

The hysteresis of the solution-processed oxide thin-film transistors (TFTs) is fatal issue to interrupt stable operation. So, we came up with uni-directional pre-annealing to solve the problem. There are inevitable defects when solution-processed oxide TFTs are fabricated, due to the porosities by the solvent volatilization. Also oxygen vacancies needed for carrier generation in metal oxide semiconductor can be trap states inducing charge carrier trapping. Uni-directional pre-annealing improved the hysteresis, preventing randomly solvent evaporation and decreased the defects of the film. We can result in advanced stability of the solution-processed oxide TFTs, at the same time showing that the field effect mobility was enhanced from 3.35 cm2/Vs to 4.78 cm2/Vs simultaneously, and exhibiting better subthreshold swing from 0.89 V/dec to 0.23 V/dec.

Information technology and hospice palliative care: social, cultural, ethical and technical implications in a rural setting.

PubMed

Kuziemsky, Craig; Jewers, Heather; Appleby, Brenda; Foshay, Neil; Maccaull, Wendy; Miller, Keith; Macdonald, Madonna

2012-01-01

There is a need to better understand the specific settings in which health information technology (HIT) is used and implemented. Factors that will determine the successful implementation of HIT are context-specific and often reside not at the technical level but rather at the process and people level. This paper provides the results of a needs assessment for HIT to support hospice palliative care (HPC) delivery in rural settings. Roundtable discussions using the nominal group technique were done to identify priority issues regarding HIT usage to support rural HPC delivery. Qualitative content analysis was then used to identify sociotechnical themes from the roundtable data. Twenty priority issues were identified at the roundtable session. Content analysis grouped the priority issues into one central theme and five supporting themes to form a sociotechnical framework for patient-centered care in rural settings. There are several sociotechnical themes and associated issues that need to be considered prior to implementing HIT in rural HPC settings. Proactive evaluation of these issues can enhance HIT implementation and also help to make ethical aspects of HIT design more explicit.

Health-Based Capitation Risk Adjustment in Minnesota Public Health Care Programs

PubMed Central

Gifford, Gregory A.; Edwards, Kevan R.; Knutson, David J.

2004-01-01

This article documents the history and implementation of health-based capitation risk adjustment in Minnesota public health care programs, and identifies key implementation issues. Capitation payments in these programs are risk adjusted using an historical, health plan risk score, based on concurrent risk assessment. Phased implementation of capitation risk adjustment for these programs began January 1, 2000. Minnesota's experience with capitation risk adjustment suggests that: (1) implementation can accelerate encounter data submission, (2) administrative decisions made during implementation can create issues that impact payment model performance, and (3) changes in diagnosis data management during implementation may require changes to the payment model. PMID:25372356

Preparing for national implementation of an evidence-based, effective HIV prevention program among bahamian sixth-grade students.

PubMed

Knowles, Valerie; Wang, Bo; Deveaux, Lynette; Lunn, Sonja; Rolle, Glenda; Jones, Giavana; Harris, Carole; Kaljee, Linda; Li, Xiaoming; Koci, Veronica; Chen, Xinguang; Marshall, Sharon; Stanton, Bonita

2012-01-01

Using data from the preparatory phase prior to national implementation of an effective HIV prevention program (Focus on Youth in the Caribbean; FOYC) in all Bahamian government sixth-grade classes, we describe (1) actual FOYC implementation, (2) factors that influenced implementation, and (3) the relationship of implementation with intervention outcome. Six elementary schools (with 17 grade six classrooms) were selected to participate in the preparatory phase. The 17 teachers were invited to attend a training workshop, coordinate administration of questionnaires to the students, teach the 10 sessions of FOYC and complete self-assessment checklists. A total of 395 students submitted baseline and 311 students submitted year-end questionnaires. Thirteen teachers initiated FOYC; five completed all 10 sessions. Implementation of FOYC was not related to teacher FOYC workshop experience but did cluster by school. There were significant positive correlations between improved student knowledge of HIV/AIDS, protective health skills, perceived parental monitoring and reduced risk behaviours with the number of FOYC sessions delivered. Implementation was impeded by logistics issues, structural issues with the measures, and comfort-level issues, most of which can be addressed for national implementation. Degree of FOYC implementation is correlated with positive student outcomes.

A combined interfacial and in-situ polymerization strategy to construct well-defined core-shell epoxy-containing SiO2-based microcapsules with high encapsulation loading, super thermal stability and nonpolar solvent tolerance

NASA Astrophysics Data System (ADS)

Jia; Wang; Tian; Li; Xu; Jiao; Cao; Wu

2016-10-01

SiO2-based microcapsules containing hydrophobic molecules exhibited potential applications such as extrinsic self-healing, drug delivery, due to outstanding thermal and chemical stability of SiO2. However, to construct SiO2-based microcapsules with both high encapsulation loading and long-term structural stability is still a troublesome issue, limiting their further utilization. We herein design a single-batch route, a combined interfacial and in-situ polymerization strategy, to fabricate epoxy-containing SiO2-based microcapsules with both high encapsulation loading and long-term structural stability. The final SiO2-based microcapsules preserve high encapsulation loading of 85.7 wt% by controlling exclusively hydrolysis and condensed polymerization at oil/water interface in the initial interfacial polymerization step. In the subsequent in-situ polymerization step, the initial SiO2-based microcapsules as seeds could efficiently harvest SiO2 precursors and primary SiO2 particles to finely tune the SiO2 wall thickness, thereby enhancing long-term structural stability of the final SiO2-based microcapsules including high thermal stability with almost no any weight loss until 250°C, and strong tolerance against nonpolar solvents such as CCl4 with almost unchanged core-shell structure and unchanged core weight after immersing into strong solvents for up to 5 days. These SiO2-based microcapsules are extremely suited for processing them into anticorrosive coating in the presence of nonpolar solvents for self-healing application.

Solvent-Assisted Gel Printing for Micropatterning Thin Organic-Inorganic Hybrid Perovskite Films.

PubMed

Jeong, Beomjin; Hwang, Ihn; Cho, Sung Hwan; Kim, Eui Hyuk; Cha, Soonyoung; Lee, Jinseong; Kang, Han Sol; Cho, Suk Man; Choi, Hyunyong; Park, Cheolmin

2016-09-27

While tremendous efforts have been made for developing thin perovskite films suitable for a variety of potential photoelectric applications such as solar cells, field-effect transistors, and photodetectors, only a few works focus on the micropatterning of a perovskite film which is one of the most critical issues for large area and uniform microarrays of perovskite-based devices. Here we demonstrate a simple but robust method of micropatterning a thin perovskite film with controlled crystalline structure which guarantees to preserve its intrinsic photoelectric properties. A variety of micropatterns of a perovskite film are fabricated by either microimprinting or transfer-printing a thin spin-coated precursor film in soft-gel state with a topographically prepatterned elastomeric poly(dimethylsiloxane) (PDMS) mold, followed by thermal treatment for complete conversion of the precursor film to a perovskite one. The key materials development of our solvent-assisted gel printing is to prepare a thin precursor film with a high-boiling temperature solvent, dimethyl sulfoxide. The residual solvent in the precursor gel film makes the film moldable upon microprinting with a patterned PDMS mold, leading to various perovskite micropatterns in resolution of a few micrometers over a large area. Our nondestructive micropatterning process does not harm the intrinsic photoelectric properties of a perovskite film, which allows for realizing arrays of parallel-type photodetectors containing micropatterns of a perovskite film with reliable photoconduction performance. The facile transfer of a micropatterned soft-gel precursor film on other substrates including mechanically flexible plastics can further broaden its applications to flexible photoelectric systems.

Hybrid MC/QC simulations of water-assisted proton transfer in nucleosides. Guanosine and its analog acyclovir.

PubMed

Markova, Nadezhda; Pejov, Ljupco; Stoyanova, Nina; Enchev, Venelin

2017-05-01

To provide an in-depth insight into the molecular basis of spontaneous tautomerism in DNA and RNA base pairs, a hybrid Monte Carlo (MC)-quantum chemical (QC) methodology is implemented to map two-dimensional potential energy surfaces along the reaction coordinates of solvent-assisted proton transfer processes in guanosine and its analog acyclovir in aqueous solution. The solvent effects were simulated by explicit inclusion of water molecules that model the relevant part of the first hydration shell around the solute. The position of these water molecules was estimated by carrying out a classical Metropolis Monte Carlo simulation of dilute water solutions of the guanosine (Gs) and acyclovir (ACV) and subsequently analyzing solute-solvent intermolecular interactions in the statistically-independent MC-generated configurations. The solvent-assisted proton transfer processes were further investigated using two different ab initio MP2 quantum chemical approaches. In the first one, potential energy surfaces of the 'bare' finite solute-solvent clusters containing Gs/ACV and four water molecules (MP2/6-31+G(d,p) level) were explored, while within the second approach, these clusters were embedded in 'bulk' solvent treated as polarizable continuum (C-PCM/MP2/6-31+G(d,p) level of theory). It was found that in the gas phase and in water solution, the most stable tautomer for guanosine and acyclovir is the 1H-2-amino-6-oxo form followed by the 2-amino-6-(sZ)-hydroxy form. The energy barriers of the water-assisted proton transfer reaction in guanosine and in acyclovir are found to be very similar - 11.74 kcal mol -1 for guanosine and 11.16 kcal mol -1 for acyclovir, and the respective rate constants (k = 1.5 × 10 1 s -1 , guanosine and k = 4.09 × 10 1 s -1 , acyclovir), are sufficiently large to generate the 2-amino-6-(sZ)-hydroxy tautomer. The analysis of the reaction profiles in both compounds shows that the proton transfer processes occur through the asynchronous concerted mechanism.

Quantum dynamics in continuum for proton transport II: Variational solvent-solute interface.

PubMed

Chen, Duan; Chen, Zhan; Wei, Guo-Wei

2012-01-01

Proton transport plays an important role in biological energy transduction and sensory systems. Therefore, it has attracted much attention in biological science and biomedical engineering in the past few decades. The present work proposes a multiscale/multiphysics model for the understanding of the molecular mechanism of proton transport in transmembrane proteins involving continuum, atomic, and quantum descriptions, assisted with the evolution, formation, and visualization of membrane channel surfaces. We describe proton dynamics quantum mechanically via a new density functional theory based on the Boltzmann statistics, while implicitly model numerous solvent molecules as a dielectric continuum to reduce the number of degrees of freedom. The density of all other ions in the solvent is assumed to obey the Boltzmann distribution in a dynamic manner. The impact of protein molecular structure and its charge polarization on the proton transport is considered explicitly at the atomic scale. A variational solute-solvent interface is designed to separate the explicit molecule and implicit solvent regions. We formulate a total free-energy functional to put proton kinetic and potential energies, the free energy of all other ions, and the polar and nonpolar energies of the whole system on an equal footing. The variational principle is employed to derive coupled governing equations for the proton transport system. Generalized Laplace-Beltrami equation, generalized Poisson-Boltzmann equation, and generalized Kohn-Sham equation are obtained from the present variational framework. The variational solvent-solute interface is generated and visualized to facilitate the multiscale discrete/continuum/quantum descriptions. Theoretical formulations for the proton density and conductance are constructed based on fundamental laws of physics. A number of mathematical algorithms, including the Dirichlet-to-Neumann mapping, matched interface and boundary method, Gummel iteration, and Krylov space techniques are utilized to implement the proposed model in a computationally efficient manner. The gramicidin A channel is used to validate the performance of the proposed proton transport model and demonstrate the efficiency of the proposed mathematical algorithms. The proton channel conductances are studied over a number of applied voltages and reference concentrations. A comparison with experimental data verifies the present model predictions and confirms the proposed model. Copyright © 2011 John Wiley & Sons, Ltd.

Issues in Planning and Implementing National Literacy Programmes.

ERIC Educational Resources Information Center

Carron, G., Ed.; Bordia, A., Ed.

The following papers were produced by participants and resource persons on specific issues of planning, management and implementation of literacy and post-literacy strategies: "People's Participation and Mobilization: Characteristics of the Literacy Campaigns in China" (Yanwei); "Strategies for Mobilization and Participation of…

Permitted Daily Exposure for Diisopropyl Ether as a Residual Solvent in Pharmaceuticals

PubMed Central

Evandri, Maria Grazia

2018-01-01

Solvents can be used in the manufacture of medicinal products provided their residual levels in the final product comply with the acceptable limits based on safety data. At worldwide level, these limits are set by the “Guideline Q3C (R6) on impurities: guideline for residual solvents” issued by the ICH. Diisopropyl ether (DIPE) is a widely used solvent but the possibility of using it in the pharmaceutical manufacture is uncertain because the ICH Q3C guideline includes it in the group of solvents for which “no adequate toxicological data on which to base a Permitted Daily Exposure (PDE) was found”. We performed a risk assessment of DIPE based on available toxicological data, after carefully assessing their reliability using the Klimisch score approach. We found sufficiently reliable studies investigating subchronic, developmental, neurological toxicity and carcinogenicity in rats and genotoxicity in vitro. Recent studies also investigated a wide array of toxic effects of gasoline/DIPE mixtures as compared to gasoline alone, thus allowing identifying the effects of DIPE itself. These data allowed a comprehensive toxicological evaluation of DIPE. The main target organs of DIPE toxicity were liver and kidney. DIPE was not teratogen and had no genotoxic effects, either in vitro or in vivo. However, it appeared to increase the number of malignant tumors in rats. Therefore, DIPE could be considered as a non-genotoxic animal carcinogen and a PDE of 0.98 mg/day was calculated based on the lowest No Observed Effect Level (NOEL) value of 356 mg/m3 (corresponding to 49 mg/kg/day) for maternal toxicity in developmental rat toxicity study. In a worst-case scenario, using an exceedingly high daily dose of 10 g/day, allowed DIPE concentration in pharmaceutical substances would be 98 ppm, which is in the range of concentration limits for ICH Q3C guideline class 2 solvents. This result might be considered for regulatory decisions. PMID:29686773

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

NASA Astrophysics Data System (ADS)

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 approach served as eco-friendly compelling alternate to conventional techniques involving organic solvents.

Morphology, directed self-assembly and pattern transfer from a high molecular weight polystyrene-block-poly(dimethylsiloxane) block copolymer film

NASA Astrophysics Data System (ADS)

Cheng, Li-Chen; Bai, Wubin; Fernandez Martin, Eduardo; Tu, Kun-Hua; Ntetsikas, Konstantinos; Liontos, George; Avgeropoulos, Apostolos; Ross, C. A.

2017-04-01

The self-assembly of block copolymers with large feature sizes is inherently challenging as the large kinetic barrier arising from chain entanglement of high molecular weight (MW) polymers limits the extent over which long-range ordered microdomains can be achieved. Here, we illustrate the evolution of thin film morphology from a diblock copolymer of polystyrene-block-poly(dimethylsiloxane) exhibiting total number average MW of 123 kg mol-1, and demonstrate the formation of layers of well-ordered cylindrical microdomains under appropriate conditions of binary solvent mix ratio, commensurate film thickness, and solvent vapor annealing time. Directed self-assembly of the block copolymer within lithographically patterned trenches occurs with alignment of cylinders parallel to the sidewalls. Fabrication of ordered cobalt nanowire arrays by pattern transfer was also implemented, and their magnetic properties and domain wall behavior were characterized.

Sequential Design of Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson-Cook, Christine Michaela

2017-06-30

A sequential design of experiments strategy is being developed and implemented that allows for adaptive learning based on incoming results as the experiment is being run. The plan is to incorporate these strategies for the NCCC and TCM experimental campaigns to be run in the coming months. This strategy for experimentation has the advantages of allowing new data collected during the experiment to inform future experimental runs based on their projected utility for a particular goal. For example, the current effort for the MEA capture system at NCCC plans to focus on maximally improving the quality of prediction of COmore » 2 capture efficiency as measured by the width of the confidence interval for the underlying response surface that is modeled as a function of 1) Flue Gas Flowrate [1000-3000] kg/hr; 2) CO 2 weight fraction [0.125-0.175]; 3) Lean solvent loading [0.1-0.3], and; 4) Lean solvent flowrate [3000-12000] kg/hr.« less

FreeSASA: An open source C library for solvent accessible surface area calculations.

PubMed

Mitternacht, Simon

2016-01-01

Calculating solvent accessible surface areas (SASA) is a run-of-the-mill calculation in structural biology. Although there are many programs available for this calculation, there are no free-standing, open-source tools designed for easy tool-chain integration. FreeSASA is an open source C library for SASA calculations that provides both command-line and Python interfaces in addition to its C API. The library implements both Lee and Richards' and Shrake and Rupley's approximations, and is highly configurable to allow the user to control molecular parameters, accuracy and output granularity. It only depends on standard C libraries and should therefore be easy to compile and install on any platform. The library is well-documented, stable and efficient. The command-line interface can easily replace closed source legacy programs, with comparable or better accuracy and speed, and with some added functionality.

Lithium-Based High Energy Density Flow Batteries

NASA Technical Reports Server (NTRS)

Bugga, Ratnakumar V. (Inventor); West, William C. (Inventor); Kindler, Andrew (Inventor); Smart, Marshall C. (Inventor)

2014-01-01

Systems and methods in accordance with embodiments of the invention implement a lithium-based high energy density flow battery. In one embodiment, a lithium-based high energy density flow battery includes a first anodic conductive solution that includes a lithium polyaromatic hydrocarbon complex dissolved in a solvent, a second cathodic conductive solution that includes a cathodic complex dissolved in a solvent, a solid lithium ion conductor disposed so as to separate the first solution from the second solution, such that the first conductive solution, the second conductive solution, and the solid lithium ionic conductor define a circuit, where when the circuit is closed, lithium from the lithium polyaromatic hydrocarbon complex in the first conductive solution dissociates from the lithium polyaromatic hydrocarbon complex, migrates through the solid lithium ionic conductor, and associates with the cathodic complex of the second conductive solution, and a current is generated.

Desorption electrospray ionization mass spectrometry of DNA nucleobases: implications for a liquid film model.

PubMed

Qiu, Bo; Luo, Hai

2009-05-01

Desorption electrospray ionization (DESI) mass spectrometry has been implemented on a commercial ion-trap mass spectrometer and used to optimize mass spectrometric conditions for DNA nucleobases: adenine, cytosine, thymine, and guanine. Experimental parameters including spray voltage, distance between mass spectrometer inlet and the sampled spot, and nebulizing gas inlet pressure were optimized. Cluster ions including some magic number clusters of nucleobases were observed for the first time using DESI mass spectrometry. The formation of the cluster species was found to vary with the nucleobases, acidification of the spray solvent, and the deposited sample amount. All the experimental results can be explained well using a liquid film model based on the two-step droplet pick-up mechanism. It is further suggested that solubility of the analytes in the spray solvent is an important factor to consider for their studies by using DESI. 2009 John Wiley & Sons, Ltd.

Many-body optimization using an ab initio monte carlo method.

PubMed

Haubein, Ned C; McMillan, Scott A; Broadbelt, Linda J

2003-01-01

Advances in computing power have made it possible to study solvated molecules using ab initio quantum chemistry. Inclusion of discrete solvent molecules is required to determine geometric information about solute/solvent clusters. Monte Carlo methods are well suited to finding minima in many-body systems, and ab initio methods are applicable to the widest range of systems. A first principles Monte Carlo (FPMC) method was developed to find minima in many-body systems, and emphasis was placed on implementing moves that increase the likelihood of finding minimum energy structures. Partial optimization and molecular interchange moves aid in finding minima and overcome the incomplete sampling that is unavoidable when using ab initio methods. FPMC was validated by studying the boron trifluoride-water system, and then the method was used to examine the methyl carbenium ion in water to demonstrate its application to solvation problems.

Environmentally compatible hand wipe cleaning solvents

NASA Technical Reports Server (NTRS)

Clayton, Catherine P.; Kovach, Michael P.

1995-01-01

Several solvents of environmental concern have previously been used for hand wipe cleaning of SRB surfaces, including 1,1,1-trichloroethane, perchloroethylene, toluene, xylene, and MEK. USBI determined the major types of surfaces involved, and qualification requirements of replacement cleaning agents. Nineteen environmentally compatible candidates were tested on 33 material substrates with 26 types of potential surface contaminants, involving over 7,000 individual evaluations. In addition to the cleaning performance evaluation, bonding, compatibility, and corrosion tests were conducted. Results showed that one cleaner was not optimum for all surfaces. In most instances, some of the candidates cleaned better than the 1,1,1-trichloroethane baseline control. Aqueous cleaners generally cleaned better, and were more compatible with nonmetallic materials, such as paints, plastics, and elastomers. Organic base cleaners were better on metal surfaces. Five cleaners have been qualified and are now being implemented in SRB hand wipe cleaning operations.

Towards understanding the effects of van der Waals strengths on the electric double-layer structures and capacitive behaviors

NASA Astrophysics Data System (ADS)

Yang, Huachao; Bo, Zheng; Yang, Jinyuan; Yan, Jianhua; Cen, Kefa

2017-10-01

Solid-liquid interactions are considered to play a crucial role in charge storage capability of electric double-layer capacitors (EDLCs). In this work, effects of van der Waals (VDW) strengths on the EDL structures and capacitive performances within two representative electrolytes of solvated aqueous solutions and solvent-free ionic liquids are illuminated by molecular dynamics simulations. Single crystalline metals with similar lattice constant but diverse VDW potentials are employed as electrodes. Upon enhancing VDW strengths, capacitance of aqueous electrolytes first increases conspicuously by ∼34.0% and then descends, manifesting a non-monotonic trend, which goes beyond traditional perspectives. Such unusual observation is interpreted by the excluded-volume effects stemmed from ion-solvent competitions. Stimulated by predominant coulombic interactions, more ions are aggregated at the interface despite of the increasing VDW potentials, facilitating superior screening efficiency and capacitance. However, further enhancing strengths preferentially attracts more solvents instead of ions to the electrified surface, which in turn strikingly repels ions from Helmholtz layers, deteriorating electrode capacitance. An essentially similar feather is also recognized for ionic liquids, while the corresponding mechanisms are prominently ascribed to the suppressed ionic separations issued from cation-anion competitions. We highlight that constructing electrode materials with a moderate-hydrophilicity could further advance the performances of EDLCs.

Improvement of CO2/N2 separation performance by polymer matrix cellulose acetate butyrate

NASA Astrophysics Data System (ADS)

Lee, R. J.; Jawad, Z. A.; Ahmad, A. L.; Ngo, J. Q.; Chua, H. B.

2017-06-01

With the rapid development of modern civilization, carbon dioxide (CO2) is produced in large quantities and mainly generated from industrial sectors. The gas emission is the major contributor to global warming. To address this issue, the membrane technology is implemented for the CO2 removal, due to the energy efficiency and economic advantages presented. Cellulose acetate butyrate (CAB) is selected as the polymeric material, due to the excellent film-forming properties and capable of developing a defect-free layer of neat membrane. This study described the fabrication development of CAB using a wet phase inversion method with different casting conditions. Where the composition of the casting solutions (3-5 wt %) and solvent evaporation time (4-6 min) were determined. The outcomes of these dominant parameters were then used to determine the best CAB membrane for CO2/Nitrogen (N2) separation and supported by the characterization i.e. scanning electron micrograph. Gas permeation measurements showed satisfactory performance for CAB membrane fabricated with 5 min evaporation time and 4 wt% polymer composition (M2). Where, its permeance and selectivity are 120.19 GPU and 3.17, respectively. In summary, this study showed a brief outlined of the future direction and perspective of CAB membrane for CO2/N2 separation.

Directed Self-Assembly of Triblock Copolymer on Chemical Patterns for Sub-10-nm Nanofabrication via Solvent Annealing.

PubMed

Xiong, Shisheng; Wan, Lei; Ishida, Yoshihito; Chapuis, Yves-Andre; Craig, Gordon S W; Ruiz, Ricardo; Nealey, Paul F

2016-08-23

Directed self-assembly (DSA) of block copolymers (BCPs) is a leading strategy to pattern at sublithographic resolution in the technology roadmap for semiconductors and is the only known solution to fabricate nanoimprint templates for the production of bit pattern media. While great progress has been made to implement block copolymer lithography with features in the range of 10-20 nm, patterning solutions below 10 nm are still not mature. Many BCP systems self-assemble at this length scale, but challenges remain in simultaneously tuning the interfacial energy atop the film to control the orientation of BCP domains, designing materials, templates, and processes for ultra-high-density DSA, and establishing a robust pattern transfer strategy. Among the various solutions to achieve domains that are perpendicular to the substrate, solvent annealing is advantageous because it is a versatile method that can be applied to a diversity of materials. Here we report a DSA process based on chemical contrast templates and solvent annealing to fabricate 8 nm features on a 16 nm pitch. To make this possible, a number of innovations were brought in concert with a common platform: (1) assembling the BCP in the phase-separated, solvated state, (2) identifying a larger process window for solvated triblock vs diblock BCPs as a function of solvent volume fraction, (3) employing templates for sub-10-nm BCP systems accessible by lithography, and (4) integrating a robust pattern transfer strategy by vapor infiltration of organometallic precursors for selective metal oxide synthesis to prepare an inorganic hard mask.

A comparison between state-specific and linear-response formalisms for the calculation of vertical electronic transition energy in solution with the CCSD-PCM method.

PubMed

Caricato, Marco

2013-07-28

The calculation of vertical electronic transition energies of molecular systems in solution with accurate quantum mechanical methods requires the use of approximate and yet reliable models to describe the effect of the solvent on the electronic structure of the solute. The polarizable continuum model (PCM) of solvation represents a computationally efficient way to describe this effect, especially when combined with coupled cluster (CC) methods. Two formalisms are available to compute transition energies within the PCM framework: State-Specific (SS) and Linear-Response (LR). The former provides a more complete account of the solute-solvent polarization in the excited states, while the latter is computationally very efficient (i.e., comparable to gas phase) and transition properties are well defined. In this work, I review the theory for the two formalisms within CC theory with a focus on their computational requirements, and present the first implementation of the LR-PCM formalism with the coupled cluster singles and doubles method (CCSD). Transition energies computed with LR- and SS-CCSD-PCM are presented, as well as a comparison between solvation models in the LR approach. The numerical results show that the two formalisms provide different absolute values of transition energy, but similar relative solvatochromic shifts (from nonpolar to polar solvents). The LR formalism may then be used to explore the solvent effect on multiple states and evaluate transition probabilities, while the SS formalism may be used to refine the description of specific states and for the exploration of excited state potential energy surfaces of solvated systems.

A 20 MHz CMOS reorder buffer for a superscalar microprocessor

NASA Technical Reports Server (NTRS)

Lenell, John; Wallace, Steve; Bagherzadeh, Nader

1992-01-01

Superscalar processors can achieve increased performance by issuing instructions out-of-order from the original sequential instruction stream. Implementing an out-of-order instruction issue policy requires a hardware mechanism to prevent incorrectly executed instructions from updating register values. A reorder buffer can be used to allow a superscalar processor to issue instructions out-of-order and maintain program correctness. This paper describes the design and implementation of a 20MHz CMOS reorder buffer for superscalar processors. The reorder buffer is designed to accept and retire two instructions per cycle. A full-custom layout in 1.2 micron has been implemented, measuring 1.1058 mm by 1.3542 mm.

'Virtual' central business office: how UMMS improved revenue cycle performance.

PubMed

Henciak, Bill; Fontaine, Christine; Fields, Keith; Parks, Stacy

2010-06-01

Based on its experience with implementing a virtual central business office, UMMS recommends the following steps to ensure the success of such an initiative: Define the process flow for the organization's day-today revenue cycle operations prior to implementation. Then select best practices and milestones for managing accounts. Identify any possible technology issues that could arise during implementation prior to go live. Hold a midproject debriefing with staff. Develop an organizational chart that details who is responsible for handling issues that arise during implementation and afterward.

GASB's New Financial Reporting Model: Implementation Project for School Districts.

ERIC Educational Resources Information Center

Bean, David; Glick, Paul

1999-01-01

In June 1999, the Governmental Accounting Standards Board (GASB) issued its statement on the structure of the basic financial reporting model for state and local governments. Explains the new financial reporting model and reviews the implementation issues that school districts will need to address. (MLF)

Filling the healthcare IT gap by 2015.

PubMed

Bigalke, John T

2009-06-01

Healthcare organizations have been slow to adopt health IT. However, the government stimulus package and impending fines for hospitals that have not implemented HIT by 2015 will motivate adoption. Issues confronting healthcare executives include selection of vendors, command of privacy and security issues, and implementation of industry standards.

Comprehensive Metric Education Project: Implementing Metrics at a District Level Administrative Guide.

ERIC Educational Resources Information Center

Borelli, Michael L.

This document details the administrative issues associated with guiding a school district through its metrication efforts. Issues regarding staff development, curriculum development, and the acquisition of instructional resources are considered. Alternative solutions are offered. Finally, an overall implementation strategy is discussed with…

Theory of complicated liquids. Investigation of liquids, solvents and solvent effects with modern theoretical methods

NASA Astrophysics Data System (ADS)

Kirchner, Barbara

2007-03-01

It is the aim of this work to elucidate the usefulness and feasibility of the first-principles approach and to extend it to the regime of liquid molecular substances of complex structure. Physical and thermodynamic properties of complicated liquids are investigated by means of Car-Parrinello molecular dynamics (CPMD) and also with static quantum chemical methods. The connection between the dynamic and static approach is given by the quantum cluster equilibrium (QCE) theory. Since the QCE theory is not yet well established, a new implementation in the MD post-processing program P EACEMAKER is presented. It can be shown that it is by far more important to include cooperative effects rather than to concentrate the effort on the inclusion of weak dispersion forces not present in current density functionals. Traditionally, investigations of complicated liquids were also undertaken with the tools of simple liquids, because for some problems the size of the system does not allow for a more accurate description. Although linear-scaling techniques are simplifications from the point of view of quantum chemistry, they might be severe improvements when compared to traditional molecular dynamics simulations. For the interpretation of the liquid state the introduction of local properties is inevitable. New methods are presented for the calculation of local dipole moments and for the estimation of hydrogen bond energies in quantum mechanically nondecomposable systems. The latter also allows for the detection of hydrogen bonds in simulations through a wavefunction-based criterion instead of one which is solely grounded on the geometric structure of the atomic nuclei involved. The article then discusses prominent liquids which show properties that are not yet understood. Another part of the work analyzes the effect of solvent molecules on solutes and their reactions in the solvent. Finaly, neoteric solvents, such as ionic liquids are discussed.

Joint Service Solvent Substitution (JS3)

DTIC Science & Technology

2012-05-01

Process Evaluation Acceptance Criteria Market Research Demonstration Plan Demonstration Validate Implementation Approval Start Approval...PRF-63460D Mg (AZ 31B-H24) mg/cm^2 0.7 Mg (SAE AMS 4377) “ Al (AMS-QQ-A-250) “ Al (7075-T6) “ 0.49 Ti (AMS 4911, 6AL- 4V ...properties – Evaluation of vendor test results – Industry experience – DOD Aerospace & Shipbuilding NESHAP experience Market Research 21 Approved for

PDB_Hydro: incorporating dipolar solvents with variable density in the Poisson-Boltzmann treatment of macromolecule electrostatics.

PubMed

Azuara, Cyril; Lindahl, Erik; Koehl, Patrice; Orland, Henri; Delarue, Marc

2006-07-01

We describe a new way to calculate the electrostatic properties of macromolecules which eliminates the assumption of a constant dielectric value in the solvent region, resulting in a Generalized Poisson-Boltzmann-Langevin equation (GPBLE). We have implemented a web server (http://lorentz.immstr.pasteur.fr/pdb_hydro.php) that both numerically solves this equation and uses the resulting water density profiles to place water molecules at preferred sites of hydration. Surface atoms with high or low hydration preference can be easily displayed using a simple PyMol script, allowing for the tentative prediction of the dimerization interface in homodimeric proteins, or lipid binding regions in membrane proteins. The web site includes options that permit mutations in the sequence as well as reconstruction of missing side chain and/or main chain atoms. These tools are accessible independently from the electrostatics calculation, and can be used for other modeling purposes. We expect this web server to be useful to structural biologists, as the knowledge of solvent density should prove useful to get better fits at low resolution for X-ray diffraction data and to computational biologists, for whom these profiles could improve the calculation of interaction energies in water between ligands and receptors in docking simulations.

Analytical Eco-Scale for Assessing the Greenness of a Developed RP-HPLC Method Used for Simultaneous Analysis of Combined Antihypertensive Medications.

PubMed

Mohamed, Heba M; Lamie, Nesrine T

2016-09-01

In the past few decades the analytical community has been focused on eliminating or reducing the usage of hazardous chemicals and solvents, in different analytical methodologies, that have been ascertained to be extremely dangerous to human health and environment. In this context, environmentally friendly, green, or clean practices have been implemented in different research areas. This study presents a greener alternative of conventional RP-HPLC methods for the simultaneous determination and quantitative analysis of a pharmaceutical ternary mixture composed of telmisartan, hydrochlorothiazide, and amlodipine besylate, using an ecofriendly mobile phase and short run time with the least amount of waste production. This solvent-replacement approach was feasible without compromising method performance criteria, such as separation efficiency, peak symmetry, and chromatographic retention. The greenness profile of the proposed method was assessed and compared with reported conventional methods using the analytical Eco-Scale as an assessment tool. The proposed method was found to be greener in terms of usage of hazardous chemicals and solvents, energy consumption, and production of waste. The proposed method can be safely used for the routine analysis of the studied pharmaceutical ternary mixture with a minimal detrimental impact on human health and the environment.

Implementing programs for chronic illness management: the case of hypertension services.

PubMed

Christianson, J B; Pietz, L; Taylor, R; Woolley, A; Knutson, D J

1997-11-01

This article describes the process by which HealthSystem Minnesota (a vertically integrated health care organization), functioning in a competitive managed care environment, has been implementing a hypertension services program. The program involves a team approach to care, with emphasis on patient participation in treatment; decentralized care delivery by nurse coordinators at primary care practice sites; ongoing training and education for patients and providers; and the continuous monitoring and evaluation of patient outcomes and satisfaction. JOB-LEVEL ISSUES: A variety of issues, such as the role and responsibilities of the nurse coordinator, became evident as the program moved towards operational status at four primary care practice sites, which prolonged the implementation period. PROCESS-LEVEL ISSUES: Issues relating to work process changes were more complicated to resolve and required, in some cases, changes in the proposed model. The most significant process-level issues related to educating physicians about the program to secure their participation and support. ORGANIZATION-LEVEL ISSUES: Such issues, which were the most difficult for program implementors to anticipate and resolve, included an organizational culture that emphasized decision making autonomy at primary practice sites. In part, the difficulty encountered in resolving organization-level issues reflected the implementors' lack of awareness of the strength or complexity of the environmental pressures facing the organization, as well as a lack of sensitivity to nuances relating to organizational culture. Two groups of hypertensive patients--at the implementation and comparison sites--will be compared with respect to satisfaction with care, clinical outcomes, and costs. Expansion of the model to patients with other chronic conditions is under consideration.

Implementation Issues in Federal Reform Efforts in Education: The United States and Australia.

ERIC Educational Resources Information Center

Porter, Paige

Multiple data sources are used in this study of educational change in the United States and Australia. The author considers political issues that may affect the implementation of educational reform efforts at the federal level, such as homogeneity versus heterogeneity, centralization versus decentralization, constitutional responsibility for…

From EDI to Internet Commerce: The BHP Steel Experience.

ERIC Educational Resources Information Center

Chan, Caroline; Swatman, Paula M. C.

2000-01-01

Discusses the issue of business-to-business electronic commerce implementation and the factors affecting it. Discusses electronic data interchange technology, describes the results of a case study of BHP Steel (Australia), and considers paradigm shifts in implementation issues related to electronic commerce that occur over time. (Author/LRW)

Administrative Issues in Planning a Library End User Searching Program. ERIC Digest.

ERIC Educational Resources Information Center

Machovec, George S.

This digest presents a reprint of an article which examines management principles that should be considered when implementing library end user searching programs. A brief discussion of specific implementation issues includes needs assessment, hardware, software, training, budgeting, what systems to offer, publicity and marketing, policies and…

Extending Engineering Design Graphics Laboratories to Have a CAD/CAM Component: Implementation Issues.

ERIC Educational Resources Information Center

Juricic, Davor; Barr, Ronald E.

1996-01-01

Reports on a project that extended the Engineering Design Graphics curriculum to include instruction and laboratory experience in computer-aided design, analysis, and manufacturing (CAD/CAM). Discusses issues in project implementation, including introduction of finite element analysis to lower-division students, feasibility of classroom prototype…

Issues Emerging from First-Year PDS Implementation.

ERIC Educational Resources Information Center

Castle, Sharon; Groth, Lois; Shaklee, Beverly

This paper focuses on a revised Professional Development School (PDS) program and what participant groups perceived to be key issues during the first year of implementation. It addresses the role of PDSs in improving the quality of beginning teachers within a non-supportive state policy environment. The George Mason University Elementary program…

75 FR 39443 - Implementation of OMB Guidance on Drug-Free Workplace Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-09

... (DOE) is removing its regulation implementing the Governmentwide common rule on drug-free workplace... drug legislation on November 18, 1988. Federal agencies issued an interim final common rule to... Governmentwide common rule on nonprocurement suspension and debarment. The agencies issued a final common rule...

Implementation of Service-Learning in Business Education: Issues and Challenges

ERIC Educational Resources Information Center

Poon, Patrick; Chan, Tsang Sing; Zhou, Lianxi

2011-01-01

This paper examines the issues and challenges in the implementation of service-learning in undergraduate business education. It also provides an assessment of the students' learning efficacy and outcomes over time through the service-learning participation. Service-learning is a pedagogical approach that integrates academic learning and community…

Commentary: The Tyranny of Time and the Reality Principle

ERIC Educational Resources Information Center

Gersten, Russell

2016-01-01

Each of the five articles in this special issue gets "into the weeds" in terms of studying actual classroom or school implementation of evidence-based or promising practices. Virtually all confront the issue of logistics and establishing an infrastructure for ensuring adequate implementation. In general, those studies that ask teachers…

Environmental Stewardship at the Savannah River Site: Generations of Success - 13212

DOE Office of Scientific and Technical Information (OSTI.GOV)

Looney, Brian B.; Bergren, Christopher L.; Gaughan, Thomas F.

2013-07-01

Approximately sixty years ago, the Savannah River Site (SRS) was built to produce nuclear materials. SRS production operations impacted air, soil, groundwater, ecology, and the local environment. Throughout its history, SRS has addressed these contamination issues directly and has maintained a commitment to environmental stewardship. The Site boasts many environmental firsts. Notably, SRS was the first major Department of Energy (DOE) facility to perform a baseline ecological assessment. This pioneering effort, by Ruth Patrick and the Philadelphia Academy of Sciences, was performed during SRS planning and construction in the early 1950's. This unique early generation of work set the stagemore » for subsequent efforts. Since that time, the scientists and engineers at SRS pro-actively identified environmental problems and developed and implemented effective and efficient environmental management and remediation solutions. This second generation, spanning the 1980's through the 2000's, is exemplified by numerous large and small cleanup actions to address metals and radionuclides, solvents and hydrocarbons, facility and area decommissioning, and ecological restoration. Recently, a third generation of environmental management was initiated as part of Enterprise SRS. This initiative to 'Develop and Deploy Next Generation Cleanup Technologies' formalizes and organizes the major technology matching, development, and implementation processes associated with historical SRS cleanup success as a resource to support future environmental management missions throughout DOE. The four elements of the current, third generation, effort relate to: 1) transition from active to passive cleanup, 2) in situ decommissioning of large nuclear facilities, 3) new long term monitoring paradigms, and 4) a major case study related to support for recovery and restoration of the Japanese Fukushima-Daiichi nuclear power plant and surrounding environment. (authors)« less

Demonstration of Advanced CO 2 Capture Process Improvements for Coal-Fired Flue Gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carroll, John

This document summarizes the activities of Cooperative Agreement DE-FE0026590, “Demonstration of Advanced CO 2 Capture Process Improvements for Coal-Fired Flue Gas” during the performance period of October 1, 2015 through May 31, 2017. This project was funded by the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL). Southern Company Services, Inc. (SCS) was the prime contractor and co-funder of the project. Mitsubishi Heavy Industries America (MHIA) and AECOM were project team members. The overall project objective was to improve costs, energy requirements, and performance of an existing amine-based CO 2 capture process. This will occur via improvements inmore » three areas: 1. Reboiler design – The first objective of the program was to demonstrate performance of an integrated stripper/reboiler (termed Built-in Reboiler, or BIR) to reduce footprint, capital costs, and integration issues of the current technology. 2. Particulate management – The second objective was to carry out a Particulate Matter Management (PMM) test. This has the potential to reduce operating costs and capital costs due to the reduced or eliminated need for mechanical filtration. 3. Solvent – The third objective was to carry out a new solvent test plan (referred to as NSL) to demonstrate a new solvent (termed New Solvent A), which is expected to reduce regeneration steam. The bulk price is also expected to be lower than KS-1, which is the current solvent used in this process. NSL testing would include baseline testing, optimization, long term testing, solvent reclamation testing, and final inspection. These combine to form the Advanced Carbon Capture (ACC) technology. Much of this work will be applicable to generic solvent processes, especially in regards to improved reboiler design, and focused to meet or exceed the DOE’s overall carbon capture performance goals of 90% CO 2 capture rate with 95% CO 2 purity at a cost of $40/tonne of CO 2 by 2025 and at a cost of electricity (COE) 30% less than baseline CO 2 capture approaches by 2030. This project was divided into two phases. Phase 1 is the planning phase, and Phase 2 is the construction, operations, testing, and analysis phase. A down select occurred after Phase 1. Phase 1 activities were carried out during this reporting period, and therefore, Phase 1 activities are solely considered in this report. The project was not selected for Phase 2 funding.« less

Solvent and α-secondary kinetic isotope effects on β-glucosidase.

PubMed

Xie, Miaomiao; Byers, Larry D

2015-11-01

β-Glucosidase from sweet almond is a retaining, family 1, glycohydrolase. It is known that glycosylation of the enzyme by aryl glucosides occurs with little, if any, acid catalysis. For this reaction both the solvent and α-secondary kinetic isotope effects are 1.0. However, for the deglucosylation reaction (e.g., kcat for 2,4-dinitrophenyl-β-D-glucopyranoside) there is a small solvent deuterium isotope effect of 1.50 (±0.06) and an α-secondary kinetic isotope effect of 1.12 (±0.03). For aryl glucosides, kcat/KM is very sensitive to the pKa of the phenol leaving group [βlg≈-1; Dale et al., Biochemistry25 (1986) 2522-2529]. With alkyl glucosides the βlg is smaller (between -0.2 and -0.3) but still negative. This, coupled with the small solvent isotope effect on the pH-independent second-order rate constant for the glucosylation of the enzyme with 2,2,2-trifluoroethyl-β-glucoside [D2O(kcat/KM)=1.23 (±0.04)] suggests that there is more glycone-aglycone bond fission than aglycone oxygen protonation in the transition state for alkyl glycoside hydrolysis. The kinetics constants for the partitioning (between water and various alcohols) of the glucosyl-enzyme intermediate, coupled with the rate constants for the forward (hydrolysis) reaction provide an estimate of the stability of the glucosyl-enzyme intermediate. This is a relatively stable species with an energy about 2 to 4 kcal/mol higher than that of the ES complex. This article is part of a Special Issue entitled: Enzyme Transition States from Theory and Experiment. Copyright © 2015 Elsevier B.V. All rights reserved.

Web Services Security - Implementation and Evaluation Issues

NASA Astrophysics Data System (ADS)

Pimenidis, Elias; Georgiadis, Christos K.; Bako, Peter; Zorkadis, Vassilis

Web services development is a key theme in the utilization the commercial exploitation of the semantic web. Paramount to the development and offering of such services is the issue of security features and they way these are applied in instituting trust amongst participants and recipients of the service. Implementing such security features is a major challenge to developers as they need to balance these with performance and interoperability requirements. Being able to evaluate the level of security offered is a desirable feature for any prospective participant. The authors attempt to address the issues of security requirements and evaluation criteria, while they discuss the challenges of security implementation through a simple web service application case.

Bioremediation of a Large Chlorinated Solvent Plume, Dover AFB, DE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bloom, Aleisa C

2015-01-01

Bioremediation of a Large Chlorinated Solvent Plume, Dover AFB, DE Aleisa Bloom, (Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA) Robert Lyon (bob.lyon@aecom.com), Laurie Stenberg, and Holly Brown (AECOM, Germantown, Maryland, USA) ABSTRACT: Past disposal practices at Dover Air Force Base (AFB), Delaware, created a large solvent plume called Area 6 (about 1 mile long, 2,000 feet wide, and 345 acres). The main contaminants are PCE, TCE, and their degradation products. The remedy is in-situ accelerated anaerobic bioremediation (AAB). AAB started in 2006 and is focusing on source areas and downgradient plume cores. Direct-push injections occurred in source areas wheremore » contamination is typically between 5 and 20 feet below ground surface. Lower concentration dissolved-phased contamination is present downgradient at 35 and 50 feet below ground surface. Here, permanent injection/extraction wells installed in transects perpendicular to the flow of groundwater are used to apply AAB. The AAB substrate is a mix of sodium lactate, emulsified vegetable oil, and nutrients. After eight years, dissolved contaminant mass within the main 80-acre treatment area has been reduced by over 98 percent. This successful application of AAB has stopped the flux of contaminants to the more distal portions of the plume. While more time is needed for effects to be seen in the distal plume, AAB injections will soon cease, and the remedy will transition to natural attenuation. INTRODUCTION Oak Ridge National Laboratory Environmental Science Division (ORNL) and AECOM (formerly URS Corporation) have successfully implemented in situ accelerated anaerobic bioremediation (AAB) to remediate chlorinated solvent contamination in a large, multi-sourced groundwater plume at Dover Air Force Base (AFB). AAB has resulted in significant reductions of dissolved phase chlorinated solvent concentrations. This plume, called Area 6, was originally over 1 mile in length and over 2,000 feet wide (Figure 1). It originated from at least four separate source areas that comingled in the subsurface to form the large plume. The major contaminants of concern (COCs) are tetrachloroethene (PCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1-TCA), which were historically used for degreasing operations in the maintenance of aircraft and support vehicles. Relatively small areas of elevated PCE, TCE, and 1,1,1-TCA were delineated in the shallow portion of the water table aquifer by direct-push groundwater sampling. Focused direct-push AAB treatment occurred in March 2006 at these source areas (Figure 1). Downgradient of the these areas and deeper in the aquifer, AAB treatment was implemented using rows of extraction/injection wells oriented perpendicular to groundwater flow to create multiple reductive zones across the plume cores, defined as areas where more than 1,000 micrograms per liter (ug/L) total solvent concentrations were present. Initial indications of successful degradation were observed within 6 months of starting injections. FIGURE 1. Dover AFB Area 6 plume. This paper describes the AAB implementation and progress of remediation after 8 years of treatment and periodic groundwater monitoring. SITE LITHOLOGY Contamination at the site is limited to the surficial aquifer, which consists of 35 to 50 feet (ft) (11 to 15 meters [m]) of unconsolidated Pleistocene deposits of the Columbia Formation. The Columbia Formation consists of fine to coarse sand with silt and clay lenses and less common gravel lenses. Silts and silty sands are generally encountered to a depth of 10 to 12 ft (3.05 to 3.65 m) below ground surface (bgs) and grade to medium- and coarse-grained sands to a depth of 35 to 50 ft (11 to 15 m) bgs. There is a clay and silt unit (part of the Calvert Formation) below the surficial aquifer that acts as an aquitard to the downward migration of contaminants. The depth to the water table varies across the site but usually ranges from 8 to 15 ft (2.4 to 4.5 m) bgs in the treatment area. REMEDIAL APPROACH AND OPERATIONS Because the Columbia Aquifer is used as a source of potable water off base, the remedial goal is to restore the aquifer to usable condition, i.e., reduce all chemicals of concern to below drinking water maximum contaminant levels (MCLs). To achieve this goal, AAB was selected as the best remedial alternative to reduce the solvent contamination. Source areas with high solvent concentrations were present in the shallow portion of the aquifer. From the source areas, dissolved solvents migrated downgradient and deeper in the aquifer with the flow of groundwater. In the deeper portion of the aquifer, the individual plumes comingle to form the larger Area 6 Plume, which covers approximately 345 acres. Types of Substrate. Previous AAB pilot tests at Dover AFB used either sodium lactate or emulsified vegetable oil (EVO) as substrates to stimulate microbial growth. The best results were obtained with...« less

Boolean and fuzzy logic implemented at the molecular level

NASA Astrophysics Data System (ADS)

Gentili, Pier Luigi

2007-07-01

In this work, it is shown how to implement both hard and soft computing by means of two structurally related heterocyclic compounds: flindersine (FL) and 6(5H)-phenanthridinone (PH). Since FL and PH have a carbonyl group in their molecular skeletons, they exhibit Proximity Effects in their photophysics. In other words, they have an emission power that can be modulated through external inputs such as temperature ( T) and hydrogen-bonding donation (HBD) ability of solvents. This phenomenology can be exploited to implement both crisp and fuzzy logic. Fuzzy Logic Systems (FLSs) wherein the antecedents of the rules are connected through the AND operator, are built by both the Mamdani's and Sugeno's models. Finally, they are adopted as approximators of the proximity effect phenomenon and tested for their prediction capabilities. Moreover, FL as photochromic compound is also a multiply configurable crisp logic molecular element.

Primary Prevention Programs at the Elementary Level: Issues of Treatment Integrity, Systematic Screening, and Reinforcement

ERIC Educational Resources Information Center

Lane, Kathleen Lynne; Kalberg, Jemma Robertson; Bruhn, Allison Leigh; Mahoney, Michelle E.; Driscoll, Steven A.

2008-01-01

This study examined issues of treatment integrity, systematic screenings, and access to reinforcement relative to school-wide positive behavior support programs (SW-PBS) implemented in two rural elementary schools during the first year of program implementation. Results suggested that treatment fidelity, as measured by self-report and direct…

Social Justice: A Long-Term Challenge for Counseling Psychology

ERIC Educational Resources Information Center

Ivey, Allen E.; Collins, Noah M.

2003-01-01

Counseling psychology has a long history of interest and commitment to social justice and multicultural issues. This article discusses some of that history and, in addition, speaks to specifics of implementing a liberation psychology frame of reference into clinical practice along with the issues of implementation and challenges faced by those of…

Non-Formal Education Implementations in Turkey: Issues and Latest Challenges

ERIC Educational Resources Information Center

Bilir, Mehmet

2007-01-01

The aim of this article is to analyse the latest implementations and issues raised in Turkish non-formal education from a historical perspective in Turkey. The high population rate and lack of adequate educational opportunities for adults and migration from rural areas to urban areas caused many educational, social and cultural problems in…

Gender Issues in the Implementation of Social Studies Curriculum in Nigerian Universities

ERIC Educational Resources Information Center

Mezieobi, Dan I.; Oyeoku, E. K.; Ezegbe, B. N.; Igbo, Janeth

2012-01-01

The study investigated gender issues in the implementation of social studies curriculum in Nigerian universities. The subjects for the study comprised of all the 200 final-year sandwich social studies students of University of Port-Harcourt in the 2009 contact session. Five research questions guided the study. Researchers developed questionnaire…

Information Retrieval System Design Issues in a Microcomputer-Based Relational DBMS Environment.

ERIC Educational Resources Information Center

Wolfram, Dietmar

1992-01-01

Outlines the file structure requirements for a microcomputer-based information retrieval system using FoxPro, a relational database management system (DBMS). Issues relating to the design and implementation of such systems are discussed, and two possible designs are examined in terms of space economy and practicality of implementation. (15…

76 FR 76609 - Implementation of Office of Management and Budget Guidance on Drug-Free Workplace Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-08

... removing its regulation implementing the Governmentwide common rule on drug-free workplace requirements for....) as a part of omnibus drug legislation. Federal agencies issued an interim final common rule to... Governmentwide common rule on nonprocurement suspension and debarment. The agencies issued a final common rule...

A Framework for Institutional Adoption and Implementation of Blended Learning in Higher Education

ERIC Educational Resources Information Center

Graham, Charles R.; Woodfield, Wendy; Harrison, J. Buckley

2013-01-01

There has been rapid growth in blended learning implementation and research focused on course-level issues such as improved learning outcomes, but very limited research focused on institutional policy and adoption issues. More institutional-level blended learning research is needed to guide institutions of higher education in strategically…

Introduction to the Special Issue: Challenges and Solutions to Implementing Effective Reading Intervention in Schools.

PubMed

Foorman, Barbara

2016-12-01

This special issue focuses on challenges and solutions to implementing effective reading intervention in schools in the United States. Researchers often develop interventions that prove effective in efficacy studies but then show no impact when implemented at scale in public school settings. The authors of the intervention studies presented here describe a number of common implementation problems stemming from research in primary grades, middle grades, and high schools. Solutions to these implementation problems include establishing researcher-practitioner partnerships to address the systems-level challenges, suggestions for how to obtain buy-in from teachers, and recommendations for reforming preservice and in-service teacher education. © 2016 Wiley Periodicals, Inc.

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.

PubMed

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.

Exclusion of Exempt Solvents From VOC Calculations

EPA Pesticide Factsheets

This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

Liposome production by microfluidics: potential and limiting factors

PubMed Central

Carugo, Dario; Bottaro, Elisabetta; Owen, Joshua; Stride, Eleanor; Nastruzzi, Claudio

2016-01-01

This paper provides an analysis of microfluidic techniques for the production of nanoscale lipid-based vesicular systems. In particular we focus on the key issues associated with the microfluidic production of liposomes. These include, but are not limited to, the role of lipid formulation, lipid concentration, residual amount of solvent, production method (including microchannel architecture), and drug loading in determining liposome characteristics. Furthermore, we propose microfluidic architectures for the mass production of liposomes with a view to potential industrial translation of this technology. PMID:27194474

Proceedings of the International Congress (12th), Corrosion Control for Low-Cost Reliability, Held in Houston, Texas on September 19 -24, 1993. Volume 3B. Corrosion: Specific Issues

DTIC Science & Technology

1993-09-24

on the MO calculations, polarised u.v. absorption spectra, solvent shifts, intensities and behaviour on protonation. 1746 EVALUATION OF ANTICORROSIVE ... method calculates the absorption and scattering effects of each element present in a sample from the fluorescent intensities measured. Standards are...for the use of the methods and materials discussed herein. Any goods, products, andlor services mentioned are mentioned as items of information only

Is a Solvent Reclamation Facility Considered a Chemical Process Plant

EPA Pesticide Factsheets

This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

Liposome production by microfluidics: potential and limiting factors.

PubMed

Carugo, Dario; Bottaro, Elisabetta; Owen, Joshua; Stride, Eleanor; Nastruzzi, Claudio

2016-05-19

This paper provides an analysis of microfluidic techniques for the production of nanoscale lipid-based vesicular systems. In particular we focus on the key issues associated with the microfluidic production of liposomes. These include, but are not limited to, the role of lipid formulation, lipid concentration, residual amount of solvent, production method (including microchannel architecture), and drug loading in determining liposome characteristics. Furthermore, we propose microfluidic architectures for the mass production of liposomes with a view to potential industrial translation of this technology.

Efficient implementation of constant pH molecular dynamics on modern graphics processors.

PubMed

Arthur, Evan J; Brooks, Charles L

2016-09-15

The treatment of pH sensitive ionization states for titratable residues in proteins is often omitted from molecular dynamics (MD) simulations. While static charge models can answer many questions regarding protein conformational equilibrium and protein-ligand interactions, pH-sensitive phenomena such as acid-activated chaperones and amyloidogenic protein aggregation are inaccessible to such models. Constant pH molecular dynamics (CPHMD) coupled with the Generalized Born with a Simple sWitching function (GBSW) implicit solvent model provide an accurate framework for simulating pH sensitive processes in biological systems. Although this combination has demonstrated success in predicting pKa values of protein structures, and in exploring dynamics of ionizable side-chains, its speed has been an impediment to routine application. The recent availability of low-cost graphics processing unit (GPU) chipsets with thousands of processing cores, together with the implementation of the accurate GBSW implicit solvent model on those chipsets (Arthur and Brooks, J. Comput. Chem. 2016, 37, 927), provide an opportunity to improve the speed of CPHMD and ionization modeling greatly. Here, we present a first implementation of GPU-enabled CPHMD within the CHARMM-OpenMM simulation package interface. Depending on the system size and nonbonded force cutoff parameters, we find speed increases of between one and three orders of magnitude. Additionally, the algorithm scales better with system size than the CPU-based algorithm, thus allowing for larger systems to be modeled in a cost effective manner. We anticipate that the improved performance of this methodology will open the door for broad-spread application of CPHMD in its modeling pH-mediated biological processes. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Biochemical quality of the pharmaceutically licensed plasma OctaplasLG after implementation of a novel prion protein (PrPSc) removal technology and reduction of the solvent/detergent (S/D) process time.

PubMed

Heger, A; Svae, T-E; Neisser-Svae, A; Jordan, S; Behizad, M; Römisch, J

2009-10-01

A new chromatographic step for the selective binding of pathological prion proteins (PrP(Sc)) to an affinity ligand, developed and optimized for PrP(Sc) capture and attached to synthetic resin particles (PRDT, USA; ProMetic BioSciences Ltd, Isle of Man, UK) was implemented into the manufacturing process of the solvent/detergent (S/D) treated biopharmaceutical quality plasma Octaplas. Pilot batches of Octaplas with the implemented chromatographic step [labelled as OctaplasLG (ligand gel)] were manufactured by Octapharma PPGmbH, Vienna, Austria. The biochemical quality was compared directly after manufacturing as well as after 18 months storage. All samples were tested on global coagulation parameters, fibrinogen levels, activities of coagulation factors and protease inhibitors, ADAMTS13 levels, as well as markers of activated coagulation and fibrinolysis. In addition, von Willebrand factor multimeric analysis was performed. The incorporation of this novel chromatography into the large-scale routine manufacturing process was shown to be technically feasible and the performance of the column was assessed to be excellent. The biochemical studies showed that Octaplas and OctaplasLG produced without and with the new column, respectively, demonstrate an identical biochemical quality. OctaplasLG remained stable over a period of 18 months stored frozen. A parallel reduction of the S/D virus inactivation step from 4-4.5 to 1-1.5 h led to significantly higher activities of plasmin inhibitor. The studies confirmed that the affinity ligand chromatography under the developed conditions can be introduced into the Octaplas manufacturing process, as a mean to reduce potentially present PrP(Sc), without hampering the proven quality of this product.

San Antonio I Software Workshop Proceedings. DoD Software for the 1990s, Held in San Antonio, Texas on 28 January - 1 February 1991

DTIC Science & Technology

1991-12-01

management and engineering issues common to the military-industrial complex, - to learn from past experience, - to understand future software...prospective policy documents. - :Prepare a draft issue paper and presentation for the DAE. These items should address the key implementation issues with...respect to MCCR software metrics and establish a clear need for DAE support. Long Term Actions ( past 12-18 mcnths) ... Draft final implementation

Implementation Issues for Departure Planning Systems

NASA Technical Reports Server (NTRS)

Hansman, R. John; Feron, Eric; Clarke, John-Paul; Odoni, Amedeo

1999-01-01

The objective of the proposed effort is to investigate issues associated with the design and implementation of decision aiding tools to assist in improving the departure process at congested airports. This effort follows a preliminary investigation of potential Departure Planning approaches and strategies, which identified potential benefits in departure efficiency, and also in reducing the environmental impact of aircraft in the departure queue. The preliminary study bas based, in large part, on observations and analysis of departure processes at Boston, Logan airport. The objective of this follow-on effort is to address key implementation issues and to expand the observational base to include airports with different constraints and traffic demand. Specifically, the objectives of this research are to: (1) Expand the observational base to include airports with different underlying operational dynamics. (2) Develop prototype decision aiding algorithms/approaches and assess potential benefits. and (3) Investigate Human Machine Integration (HMI) issues associated with decision aids in tower environments.

Qualitative and mixed methods research in dissemination and implementation science: introduction to the special issue.

PubMed

Southam-Gerow, Michael A; Dorsey, Shannon

2014-01-01

This special issue provides examples of how qualitative and mixed methods research approaches can be used in dissemination and implementation science. In this introductory article, we provide a brief rationale for why and how qualitative and mixed methods approaches can be useful in moving the field forward. Specifically, we provide a brief primer on common qualitative methods, including a review of guidelines provided by the National Institutes of Health. Next, we introduce the six articles in the issue. The first of the articles by Palinkas represents a more thorough and authoritative discussion related to qualitative methods, using the other five articles in the issue (and other published works) as examples. The remaining five articles are empirical and/or descriptive articles of recently completed or ongoing qualitative or mixed methods studies related to dissemination and implementation of evidence-based practices for children and adolescents.

System Wide Information Management (SWIM)

NASA Technical Reports Server (NTRS)

Hritz, Mike; McGowan, Shirley; Ramos, Cal

2004-01-01

This viewgraph presentation lists questions regarding the implementation of System Wide Information Management (SWIM). Some of the questions concern policy issues and strategies, technology issues and strategies, or transition issues and strategies.

Selective dissolution of halide perovskites as a step towards recycling solar cells

PubMed Central

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

2016-01-01

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells. PMID:27211006

Visualization of energy: light dose indicator based on electrochromic gyroid nano-materials

NASA Astrophysics Data System (ADS)

Wei, Di; Scherer, Maik R. J.; Astley, Michael; Steiner, Ullrich

2015-06-01

The typical applications of electrochromic devices do not make use of the charge-dependent, gradual optical response due to their slow voltage-sensitive coloration. However, in this paper we present a design for a reusable, self-powered light dose indicator consisting of a solar cell and a gyroid-structured nickel oxide (NiO) electrochromic display that measures the cumulative charge per se, making use of the efficient voltage-sensitive coloration of gyroid materials. To circumvent the stability issues associated with the standard aqueous electrolyte that is typically accompanied by water splitting and gas evolution, we investigate a novel nano-gyroid NiO electrochromic device based on organic solvents of 1,1,1,3,3,3-hexafluoropropan-2-ol, and room temperature ionic liquid (RTIL) triethylsulfonium bis(trifluoromethylsulfonyl) imide ([SET3][TFSI]) containing lithium bis(trifluoromethylsulfonyl) imide. We show that an effective light dose indicator can be enabled by nano-gyroid NiO with RTIL; this proves to be a reliable device since it does not involve solvent degradation or gas generation.

Molecular dynamics simulations of biological membranes and membrane proteins using enhanced conformational sampling algorithms☆

PubMed Central

Mori, Takaharu; Miyashita, Naoyuki; Im, Wonpil; Feig, Michael; Sugita, Yuji

2016-01-01

This paper reviews various enhanced conformational sampling methods and explicit/implicit solvent/membrane models, as well as their recent applications to the exploration of the structure and dynamics of membranes and membrane proteins. Molecular dynamics simulations have become an essential tool to investigate biological problems, and their success relies on proper molecular models together with efficient conformational sampling methods. The implicit representation of solvent/membrane environments is reasonable approximation to the explicit all-atom models, considering the balance between computational cost and simulation accuracy. Implicit models can be easily combined with replica-exchange molecular dynamics methods to explore a wider conformational space of a protein. Other molecular models and enhanced conformational sampling methods are also briefly discussed. As application examples, we introduce recent simulation studies of glycophorin A, phospholamban, amyloid precursor protein, and mixed lipid bilayers and discuss the accuracy and efficiency of each simulation model and method. This article is part of a Special Issue entitled: Membrane Proteins. Guest Editors: J.C. Gumbart and Sergei Noskov. PMID:26766517

Understanding the mechanisms of lipid extraction from microalga Chlamydomonas reinhardtii after electrical field solicitations and mechanical stress within a microfluidic device.

PubMed

Bensalem, Sakina; Lopes, Filipa; Bodénès, Pierre; Pareau, Dominique; Français, Olivier; Le Pioufle, Bruno

2018-06-01

One way envisioned to overcome part of the issues biodiesel production encounters today is to develop a simple, economically viable and eco-friendly process for the extraction of lipids from microalgae. This study investigates the lipid extraction efficiency from the microalga Chlamydomonas reinhardtii as well as the underlying mechanisms. We propose a new methodology combining a pulsed electric field (PEF) application and mechanical stresses as a pretreatment to improve lipid extraction with solvents. Cells enriched in lipids are therefore submitted to electric field pulses creating pores on the cell membrane and then subjected to a mechanical stress by applying cyclic pressures on the cell wall (using a microfluidic device). Results showed an increase in lipid extraction when cells were pretreated by the combination of both methods. Microscopic observations showed that both pretreatments affect the cell structure. Finally, the dependency of solvent lipid extraction efficiency with the cell wall structure is discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Selective dissolution of halide perovskites as a step towards recycling solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Here, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO 2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easilymore » decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb 2+ cations. After 10 cycles of recycling, a mesoporous TiO 2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.« less

Selective dissolution of halide perovskites as a step towards recycling solar cells

DOE PAGES

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; ...

2016-05-23

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Here, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO 2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easilymore » decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb 2+ cations. After 10 cycles of recycling, a mesoporous TiO 2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.« less

Implementation Issues of Virtual Desktop Infrastructure and Its Case Study for a Physician's Round at Seoul National University Bundang Hospital.

PubMed

Yoo, Sooyoung; Kim, Seok; Kim, Taegi; Kim, Jon Soo; Baek, Rong-Min; Suh, Chang Suk; Chung, Chin Youb; Hwang, Hee

2012-12-01

The cloud computing-based virtual desktop infrastructure (VDI) allows access to computing environments with no limitations in terms of time or place such that it can permit the rapid establishment of a mobile hospital environment. The objective of this study was to investigate the empirical issues to be considered when establishing a virtual mobile environment using VDI technology in a hospital setting and to examine the utility of the technology with an Apple iPad during a physician's rounds as a case study. Empirical implementation issues were derived from a 910-bed tertiary national university hospital that recently launched a VDI system. During the physicians' rounds, we surveyed patient satisfaction levels with the VDI-based mobile consultation service with the iPad and the relationship between these levels of satisfaction and hospital revisits, hospital recommendations, and the hospital brand image. Thirty-five inpatients (including their next-of-kin) and seven physicians participated in the survey. Implementation issues pertaining to the VDI system arose with regard to the highly availability system architecture, wireless network infrastructure, and screen resolution of the system. Other issues were related to privacy and security, mobile device management, and user education. When the system was used in rounds, patients and their next-of-kin expressed high satisfaction levels, and a positive relationship was noted as regards patients' decisions to revisit the hospital and whether the use of the VDI system improved the brand image of the hospital. Mobile hospital environments have the potential to benefit both physicians and patients. The issues related to the implementation of VDI system discussed here should be examined in advance for its successful adoption and implementation.

Implementation Issues of Virtual Desktop Infrastructure and Its Case Study for a Physician's Round at Seoul National University Bundang Hospital

PubMed Central

Yoo, Sooyoung; Kim, Seok; Kim, Taegi; Kim, Jon Soo; Baek, Rong-Min; Suh, Chang Suk; Chung, Chin Youb

2012-01-01

Objectives The cloud computing-based virtual desktop infrastructure (VDI) allows access to computing environments with no limitations in terms of time or place such that it can permit the rapid establishment of a mobile hospital environment. The objective of this study was to investigate the empirical issues to be considered when establishing a virtual mobile environment using VDI technology in a hospital setting and to examine the utility of the technology with an Apple iPad during a physician's rounds as a case study. Methods Empirical implementation issues were derived from a 910-bed tertiary national university hospital that recently launched a VDI system. During the physicians' rounds, we surveyed patient satisfaction levels with the VDI-based mobile consultation service with the iPad and the relationship between these levels of satisfaction and hospital revisits, hospital recommendations, and the hospital brand image. Thirty-five inpatients (including their next-of-kin) and seven physicians participated in the survey. Results Implementation issues pertaining to the VDI system arose with regard to the highly availability system architecture, wireless network infrastructure, and screen resolution of the system. Other issues were related to privacy and security, mobile device management, and user education. When the system was used in rounds, patients and their next-of-kin expressed high satisfaction levels, and a positive relationship was noted as regards patients' decisions to revisit the hospital and whether the use of the VDI system improved the brand image of the hospital. Conclusions Mobile hospital environments have the potential to benefit both physicians and patients. The issues related to the implementation of VDI system discussed here should be examined in advance for its successful adoption and implementation. PMID:23346476

Reflections on organizational issues in developing, implementing, and maintaining state Web-based data query systems.

PubMed

Love, Denise; Shah, Gulzar H

2006-01-01

Emerging technologies, such as Web-based data query systems (WDQSs), provide opportunities for state and local agencies to systematically organize and disseminate data to broad audiences and streamline the data distribution process. Despite the progress in WDQSs' implementation, led by agencies considered the "early adopters," there are still agencies left behind. This article explores the organizational issues and barriers to development of WDQSs in public health agencies and highlights factors facilitating the implementation of WDQSs.

Issues to consider before implementing digital breast tomosynthesis into a breast imaging practice.

PubMed

Hardesty, Lara A

2015-03-01

OBJECTIVE. The purpose of this article is to discuss issues surrounding the implementation of digital breast tomosynthesis (DBT) into a clinical breast imaging practice and assist radiologists, technologists, and administrators who are considering the addition of this new technology to their practices. CONCLUSION. When appropriate attention is given to image acquisition, interpretation, storage, technologist and radiologist training, patient selection, billing, radiation dose, and marketing, implementation of DBT into a breast imaging practice can be successful.

Usability and feasibility of a tablet-based Decision-Support and Integrated Record-keeping (DESIRE) tool in the nurse management of hypertension in rural western Kenya.

PubMed

Vedanthan, Rajesh; Blank, Evan; Tuikong, Nelly; Kamano, Jemima; Misoi, Lawrence; Tulienge, Deborah; Hutchinson, Claire; Ascheim, Deborah D; Kimaiyo, Sylvester; Fuster, Valentin; Were, Martin C

2015-03-01

Mobile health (mHealth) applications have recently proliferated, especially in low- and middle-income countries, complementing task-redistribution strategies with clinical decision support. Relatively few studies address usability and feasibility issues that may impact success or failure of implementation, and few have been conducted for non-communicable diseases such as hypertension. To conduct iterative usability and feasibility testing of a tablet-based Decision Support and Integrated Record-keeping (DESIRE) tool, a technology intended to assist rural clinicians taking care of hypertension patients at the community level in a resource-limited setting in western Kenya. Usability testing consisted of "think aloud" exercises and "mock patient encounters" with five nurses, as well as one focus group discussion. Feasibility testing consisted of semi-structured interviews of five nurses and two members of the implementation team, and one focus group discussion with nurses. Content analysis was performed using both deductive codes and significant inductive codes. Critical incidents were identified and ranked according to severity. A cause-of-error analysis was used to develop corresponding design change suggestions. Fifty-seven critical incidents were identified in usability testing, 21 of which were unique. The cause-of-error analysis yielded 23 design change suggestions. Feasibility themes included barriers to implementation along both human and technical axes, facilitators to implementation, provider issues, patient issues and feature requests. This participatory, iterative human-centered design process revealed previously unaddressed usability and feasibility issues affecting the implementation of the DESIRE tool in western Kenya. In addition to well-known technical issues, we highlight the importance of human factors that can impact implementation of mHealth interventions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Usability and Feasibility of a Tablet-Based Decision-Support and Integrated Record-Keeping (DESIRE) Tool in the Nurse Management of Hypertension in Rural Western Kenya

PubMed Central

Vedanthan, Rajesh; Blank, Evan; Tuikong, Nelly; Kamano, Jemima; Misoi, Lawrence; Tulienge, Deborah; Hutchinson, Claire; Ascheim, Deborah D.; Kimaiyo, Sylvester; Fuster, Valentin; Were, Martin C.

2015-01-01

Background Mobile health (mHealth) applications have recently proliferated, especially in low- and middle-income countries, complementing task-redistribution strategies with clinical decision support. Relatively few studies address usability and feasibility issues that may impact success or failure of implementation, and few have been conducted for non-communicable diseases such as hypertension. Objective To conduct iterative usability and feasibility testing of a tablet-based Decision Support and Integrated Record-keeping (DESIRE) tool, a technology intended to assist rural clinicians taking care of hypertension patients at the community level in a resource-limited setting in western Kenya. Methods Usability testing consisted of “think aloud” exercises and “mock patient encounters” with five nurses, as well as one focus group discussion. Feasibility testing consisted of semi-structured interviews of five nurses and two members of the implementation team, and one focus group discussion with nurses. Content analysis was performed using both deductive codes and significant inductive codes. Critical incidents were identified and ranked according to severity. A cause-of-error analysis was used to develop corresponding design change suggestions. Results Fifty-seven critical incidents were identified in usability testing, 21 of which were unique. The cause-of-error analysis yielded 23 design change suggestions. Feasibility themes included barriers to implementation along both human and technical axes, facilitators to implementation, provider issues, patient issues and feature requests. Conclusions This participatory, iterative human-centered design process revealed previously unaddressed usability and feasibility issues affecting the implementation of the DESIRE tool in western Kenya. In addition to well-known technical issues, we highlight the importance of human factors that can impact implementation of mHealth interventions. PMID:25612791

Systemic sclerosis and occupational risk factors: role of solvents and cleaning products.

PubMed

Maître, Anne; Hours, Martine; Bonneterre, Vincent; Arnaud, Joëlle; Arslan, Marie Tülin; Carpentier, Patrick; Bergeret, Alain; de Gaudemaris, Régis

2004-12-01

To analyze occupational and non-occupational exposure factors suspected of being associated with scleroderma (SSc), with a view to inculpating or excluding certain potentially toxic substances (e.g., solvents), thereby contributing to the recognition of such toxins in the field of occupational health. The study comprised 10 men and 83 women diagnosed with SSc between 1995 and 1999 (American College of Rheumatology criteria) and early SSc, and 206 age and sex matched controls. The SSc registry is all-inclusive in the French administrative departments of Isere and Savoie so controls were randomly selected from the general population (using telephone directories) in these departments to ensure full representation. Exposure factors were analyzed for each subject by a personal questionnaire, and an individual evaluation was carried out by an industrial expert. Data were analyzed by conditional logistical regression adjusting for educational level. Construction workers were at significantly higher risk of contracting SSc; odds ratio (OR) = 4.01 (95% confidence interval 1.14-14.09). Analysis by industrial experts identified exposure to certain toxic substances regularly used by these same workers as risk factors for SSc: cleaning products: OR = 1.66 (0.90-3.08) (both sexes) and OR = 1.71 (0.92-3.20) (women only); solvents: OR = 3.23 (1.58-6.63) (both sexes) and OR = 2.80 (1.28-6.11) (women only); synthetic adhesives: OR 25.36 (1.36-472.28) (on 3 exposed cases). Exposure to either cleaning products or solvents emerged as a risk factor for SSc. Exposure factors should be characterized and results of all studies compared to implement appropriate preventive measures in relevant workplaces.

Ionic Asymmetry and Solvent Excluded Volume Effects on Spherical Electric Double Layers: A Density Functional Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Medasani, Bharat; Ovanesyan, Zaven; Thomas, Dennis G.

In this article we present a classical density functional theory for electrical double layers of spherical macroions that extends the capabilities of conventional approaches by accounting for electrostatic ion correlations, size asymmetry and excluded volume effects. The approach is based on a recent approximation introduced by Hansen-Goos and Roth for the hard sphere excess free energy of inhomogeneous fluids (J. Chem. Phys. 124, 154506). It accounts for the proper and efficient description of the effects of ionic asymmetry and solvent excluded volume, especially at high ion concentrations and size asymmetry ratios including those observed in experimental studies. Additionally, we utilizemore » a leading functional Taylor expansion approximation of the ion density profiles. In addition, we use the Mean Spherical Approximation for multi-component charged hard sphere fluids to account for the electrostatic ion correlation effects. These approximations are implemented in our theoretical formulation into a suitable decomposition of the excess free energy which plays a key role in capturing the complex interplay between charge correlations and excluded volume effects. We perform Monte Carlo simulations in various scenarios to validate the proposed approach, obtaining a good compromise between accuracy and computational cost. We use the proposed computational approach to study the effects of ion size, ion size asymmetry and solvent excluded volume on the ion profiles, integrated charge, mean electrostatic potential, and ionic coordination number around spherical macroions in various electrolyte mixtures. Our results show that both solvent hard sphere diameter and density play a dominant role in the distribution of ions around spherical macroions, mainly for experimental water molarity and size values where the counterion distribution is characterized by a tight binding to the macroion, similar to that predicted by the Stern model.« less

Contamination of Critical Surfaces from NVR Glove Residues Via Dry Handling and Solvent Cleaning

NASA Technical Reports Server (NTRS)

Sovinski, Marjorie F.

2004-01-01

Gloves are often used to prevent the contamination of critical surfaces during handling. The type of glove chosen for use should be the glove that produces the least amount of non-volatile residue (NVR). This paper covers the analysis of polyethylene, nitrile, latex, vinyl, and polyurethane gloves using the contact transfer and gravimetric determination methods covered in the NASA GSFC work instruction Gravimetric Determination and Contact Transfer of Non-volatile Residue (NVR) in Cleanroom Glove Samples, 541-WI-5330.1.21 and in the ASTM Standard E-1731M-95, Standard Test Method for Gravimetric Determination of Non-Volatile Residue from Cleanroom Gloves. The tests performed focus on contamination of critical surfaces at the molecular level. The study found that for the most part, all of the gloves performed equally well in the contact transfer testing. However, the polyethylene gloves performed the best in the gravimetric determination testing, and therefore should be used whenever solvent contact is a possibility. The nitrile gloves may be used as a substitute for latex gloves when latex sensitivity is an issue. The use of vinyl gloves should be avoided, especially if solvent contact is a possibility. A glove database will be established by Goddard Space Flight Center (GSFC) Code 541 to compile the results from future testing of new gloves and different glove lots.

Optical filter based on Fabry-Perot structure using a suspension of goethite nanoparticles as electro-optic material

NASA Astrophysics Data System (ADS)

Abbas, Samir; Dupont, Laurent; Dozov, Ivan; Davidson, Patrick; Chanéac, Corinne

2018-02-01

We have investigated the feasibility of optical tunable filters based on a Fabry-Perot etalon that uses a suspension of goethite (α-FeOOH) nanorods as electro-optic material for application in optical telecommunications in the near IR range. These synthetic nanoparticles have a high optical anisotropy that give rise to a very strong Kerr effect in their colloidal suspensions. Currently, these particles are dispersed in aqueous solvent, with pH2 to ensure the colloidal electrostatic stability. However, the high conductivity of these suspensions requires using high-frequency electric fields (f > 1 MHz), which brings about a high power consumption of the driver. To decrease the field frequency, we have changed the solvent to ethylene glycol which has a lower electrical conductivity than the aqueous solvent. We have built a Fabry-Perot cell, filled with this colloidal suspension in the isotropic phase, and showed that a phase shift of 14 nm can be obtained in a field of 3V/μm. Therefore, the device can operate as a tunable filter. A key advantage of this filter is that it is, by principle, completely insensitive to the polarization of the input light. However, several technological issues still need to be solved, such as ionic contamination of the suspension from the blocking layers, and dielectrophoretic and thermal effects.

Supersonically Spray-Coated Colloidal Quantum Dot Ink Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Hyekyoung; Lee, Jong-Gun; Mai, Xuan Dung

Controlling the thickness of quantum dot (QD) films is difficult using existing film formation techniques, which employ pre-ligand-exchanged PbS QD inks, because of several issues: 1) poor colloidal stability, 2) use of high-boiling-point solvents for QD dispersion, and 3) limitations associated with one-step deposition. Here in this paper, we suggest a new protocol for QD film deposition using electrical double-layered PbS QD inks, prepared by solution-phase ligand exchange using methyl ammonium lead iodide (MAPbI 3). The films are deposited by the supersonic spraying technique, which facilitates the rapid evaporation of the solvent and the subsequent deposition of the PbS QDmore » ink without requiring a post-deposition annealing treatment for solvent removal. The film thickness could be readily controlled by varying the number of spraying sweeps made across the substrate. This spray deposition process yields high-quality n-type QD films quickly (within 1 min) while minimizing the amount of the PbS QD ink used to less than 5 mg for one device (300-nm-thick absorbing layer, 2.5 x 2.5 cm 2). Further, the formation of an additional p-layer by treatment with mercaptopropionic acid allows for facile hole extraction from the QD films, resulting in a power conversion efficiency of 3.7% under 1.5 AM illumination.« less

Characterization and Storage Stability Study of Bixin Extracted from Bixa orellana Using Organic Solvent

NASA Astrophysics Data System (ADS)

Husa, N. N.; Hamzah, F.; Said, H. M.

2018-05-01

Colorant is one of the additives to give a better appearance or improve the colour of the product. Synthetic colorant has been widely used in industrial due to its readiness in the market and its colour stability. However the arising issues related to the safety, nutrition and also the therapeutic effect has encouraged users to become more concern about the colouring component. Thus, the present research was conducted in order to produce natural colorant called bixin from Bixa orellana or also known as annatto seeds. The study was focusing on the effect of the solvent on the characteristic and concentration of the extracted bixin. While stability of the bixin during different storage condition was determined to further validate the effectiveness of the solvent. The result indicated that methanol and acetone gave darker of the bixin colour as compared to the water. However, the deterioration rate of the bixin in acetone and methanol were faster as compared to the water. The extracted bixin was analysed using Fourier-transform infrared spectroscopy (FTIR) and spectrophotometer analysis. The strong band for the bixin was observed at absorbance range of 1704 – 1740cm-1. The study indicates that the concentration of the extracted bixin was the highest in methanol which gave 817.7 ppm of bixin. Meanwhile, bixin concentration in acetone and water was 602.9 ppm and 477.19 ppm respectively.

Supersonically Spray-Coated Colloidal Quantum Dot Ink Solar Cells

DOE PAGES

Choi, Hyekyoung; Lee, Jong-Gun; Mai, Xuan Dung; ...

2017-04-04

Controlling the thickness of quantum dot (QD) films is difficult using existing film formation techniques, which employ pre-ligand-exchanged PbS QD inks, because of several issues: 1) poor colloidal stability, 2) use of high-boiling-point solvents for QD dispersion, and 3) limitations associated with one-step deposition. Here in this paper, we suggest a new protocol for QD film deposition using electrical double-layered PbS QD inks, prepared by solution-phase ligand exchange using methyl ammonium lead iodide (MAPbI 3). The films are deposited by the supersonic spraying technique, which facilitates the rapid evaporation of the solvent and the subsequent deposition of the PbS QDmore » ink without requiring a post-deposition annealing treatment for solvent removal. The film thickness could be readily controlled by varying the number of spraying sweeps made across the substrate. This spray deposition process yields high-quality n-type QD films quickly (within 1 min) while minimizing the amount of the PbS QD ink used to less than 5 mg for one device (300-nm-thick absorbing layer, 2.5 x 2.5 cm 2). Further, the formation of an additional p-layer by treatment with mercaptopropionic acid allows for facile hole extraction from the QD films, resulting in a power conversion efficiency of 3.7% under 1.5 AM illumination.« less

Ethical issues in the development and implementation of nutrition-related public health policies and interventions: A scoping review.

PubMed

Hurlimann, Thierry; Peña-Rosas, Juan Pablo; Saxena, Abha; Zamora, Gerardo; Godard, Béatrice

2017-01-01

The limited integration of ethics in nutrition-related public health policies and interventions is one major concern for those who have the task of implementing them. Ethical challenges that are overlooked during the development of such interventions could raise serious ethical issues during their implementation and even after. As a result, these decision makers need technical support and ethical guidance for adaptation of interventions to local (cultural, social, economic, etc.) contexts. The goal of this scoping review is to delineate and "map" the range of ethical issues in nutrition-related public health interventions, as well as the range of the various fields in which they may arise. A scoping review of empirical research and conceptual literature was conducted following the framework of Arksey and O'Malley. Searches using PubMed with Medical Subject Headings (MeSH) categories and Advanced Search Builder as well as in the Global Health Library were performed. The final sample consists of 169 publications. The ethics of public health prevention or treatment of obesity and non-communicable diseases is the most explicitly and frequently discussed subject. In comparison, ethical issues raised by public health interventions in the fields of undernutrition, breastfeeding, vitamin/mineral supplementation and food fortification, food security, food sustainability and food safety are addressed in a lower proportion of the sample. The results illustrate the various natures, types, and scopes of existing public health nutrition-related interventions, and the various ethical issues that may be raised by these interventions, in addition to the numerous and different contexts in which they may be implemented. The ethical issues faced in the development and implementation of nutrition-related public health interventions are varied and cannot be equated with, nor generalized about, when dealing with specific activities in this field. More importantly, these ethical issues cannot be managed without a careful consideration for the complexity of contexts in which nutrition-related interventions are expected to be implemented. These interventions engage a variety of actors with diverse perspectives and interests. We discuss these challenges and also comment on the importance of considering ethical impacts in the monitoring and evaluation of such interventions. General ethical frameworks or recommendations-although useful-cannot be expected to provide policy makers, implementators and other public health personnel with sufficient practical ethical guidance as they cannot consider and anticipate the particularities of all specific nutrition-related public health interventions and the complexity of the contexts in which they are implemented. Further research is needed in order to develop more targeted ethical frameworks.

Practical Issues in Developing a Culturally Tailored Physical Activity Promotion Program for Chinese and Korean American Midlife Women: A Pilot Study

PubMed Central

Chee, Wonshik; Kim, Sangmi; Chu, Tsung-Lan; Ji, Xiaopeng; Zhang, Jingwen; Chee, Eunice; Im, Eun-Ok

2016-01-01

Background With advances in computer technologies, Web-based interventions are widely accepted and welcomed by health care providers and researchers. Although the benefits of Web-based interventions on physical activity promotion have been documented, the programs have rarely targeted Asian Americans, including Asian American midlife women. Subsequently, culturally competent Web-based physical activity programs for Asian Americans may be necessary. Objective The purpose of our study was to explore practical issues in developing and implementing a culturally competent Web-based physical activity promotion program for 2 groups of Asian American women—Chinese American and Korean American midlife women—and to provide implications for future research. Methods While conducting the study, the research team members wrote individual memos on issues and their inferences on plausible reasons for the issues. The team had group discussions each week and kept the minutes of the discussions. Then, the memos and minutes were analyzed using a content analysis method. Results We identified practical issues in 4 major idea categories: (1) bilingual translators’ language orientations, (2) cultural sensitivity requirement, (3) low response rate, interest, and retention, and (4) issues in implementation logistics. Conclusions Based on the issues, we make several suggestions for the use of bilingual translators, motivational strategies, and implementation logistics. PMID:27872035

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2002-09-19

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 ofmore » 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 a centrifugal contactor for use in the CSSX process. A prototype of any centrifugal contactors designed for future pilot-scale or full-scale processing should be thoroughly tested prior to implementation.« less

Evaluation of the Hydraulic Capacity and Mass Transfer Efficiency of the CSSX Process with the Optimized Solvent in a Single Stage of 5.5-cm-Diameter Centrifugal Contactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Law, Jack Douglas; Tillotson, Richard Dean; Todd, Terry Allen

2002-09-01

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 ofmore » 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 a centrifugal contactor for use in the CSSX process. A prototype of any centrifugal contactors designed for future pilot-scale or full-scale processing should be thoroughly tested prior to implementation.« less

Implementation Issues of a Standards-Based Teacher Evaluation System: Perceptions of Campus Administrators

ERIC Educational Resources Information Center

Nixon, Lisa

2013-01-01

The purpose of this mixed methods study was to determine the key implementation issues of a standards-based teacher evaluation system as perceived by campus administrators. The 80 campus administrators that participated in this study were from six public school districts located in southeastern Texas that serve students in grades Kindergarten…

Issues and Prospects of Effetive Implementation of New Secondary School Curriculum in Nigeria

ERIC Educational Resources Information Center

Ahmadi, Ali A.; Lukman, Ajibola A.

2015-01-01

This paper digs into the issues surrounding effective implementation of new secondary school curriculum in Nigeria. This is based on the feeling that 21st century education is characterized with a dramatic technological revolution. The paper therefore portrays education in the 21st century as a total departure from the factory-model education of…

A Case Study of Issues of Strategy Implementation in Internationalization of Higher Education

ERIC Educational Resources Information Center

Jiang, Nan; Carpenter, Victoria

2013-01-01

Purpose: The purpose of this research is to identify and critically evaluate key issues faced by an institution in the quest to implement higher education internationalization. Design/methodology/approach: A qualitative research is conducted in a post-1992 UK university. A total of 20 interviewees from three key departments participated in this…

Ethics of Implementing Electronic Health Records in Developing Countries: Points to Consider

PubMed Central

Were, Martin C.; Meslin, Eric M.

2011-01-01

Electronic Health Record systems (EHRs) are increasingly being used in many developing countries, several of which have moved beyond isolated pilot projects to active large-scale implementation as part of their national health strategies. Despite growing enthusiasm for adopting EHRs in resource poor settings, almost no attention has been paid to the ethical issues that might arise. In this article we argue that these ethical issues should be addressed now if EHRs are to be appropriately implemented in these settings. We take a systematic approach guided by a widely accepted ethical framework currently in use for developing countries to first describe the ethical issues, and then propose a set of ‘Points to Consider’ to guide further thinking and decision-making. PMID:22195214

Detecting and addressing adolescent issues and concerns: evaluating the efficacy of a primary care previsit questionnaire.

PubMed

Lewin, Warren; Knäuper, Bärbel; Roseman, Michelle; Adler, Perry; Malus, Michael

2009-07-01

To assess the efficacy of a previsit questionnaire (PVQ), implemented without formal training, that was designed to screen for biomedical and psychosocial health issues and concerns among adolescent patients in a hospital-based primary care clinic, and to examine the subsequent action taken for health issues and concerns identified with the PVQ. Retrospective review of adolescent medical charts, using a pre-post design. An outpatient primary care clinic located in an urban teaching hospital in Montreal, Que. A total of 210 adolescent patients aged 13 to 19 who visited the clinic between 2000 and 2004. The type (medical vs psychosocial) and number of issues detected and actions taken by physicians in one-to-one consultations with adolescent patients 2 years before (2000-2002) and 2 years after (2002-2004) PVQ implementation, as noted in the patients' medical charts. In total, 105 charts were reviewed for each group. An increase in the number of psychosocial issues was detected following the introduction of the PVQ. An increase in the frequency of action taken for psychosocial concerns and a decrease in the frequency of medical action taken by physicians were found after PVQ implementation. More notations related to psychosocial concerns were also found in the adolescents' charts after introduction of the PVQ. A PVQ is an effective strategy to improve adolescent screening for psychosocial issues and concerns. Implementing such a questionnaire requires no training and can therefore be easily incorporated into clinical practice.

Soil Vapor Extraction Implementation Experiences

EPA Pesticide Factsheets

This issue paper identifies issues and summarizes experiences with soil vapor extraction (SVE) as a remedy for volatile organic compounds (VOCs) in soils. The issues presented here reflect discussions with over 30 Remedial Project Managers (RPMs)...

A diffusion of innovations model of physician order entry.

PubMed

Ash, J S; Lyman, J; Carpenter, J; Fournier, L

2001-01-01

To interpret the results of a cross-site study of physician order entry (POE) in hospitals using a diffusion of innovations theory framework. Qualitative study using observation, focus groups, and interviews. Data were analyzed by an interdisciplinary team of researchers using a grounded approach to identify themes. Themes were then interpreted using classical Diffusion of Innovations (DOI) theory as described by Rogers [1]. Four high level themes were identified: organizational issues; clinical and professional issues; technology implementation issues; and issues related to the organization of information and knowledge. Further analysis using the DOI framework indicated that POE is an especially complex information technology innovation when one considers communication, time, and social system issues in addition to attributes of the innovation itself. Implementation strategies for POE should be designed to account for its complex nature. The ideal would be a system that is both customizable and integrated with other parts of the information system, is implemented with maximum involvement of users and high levels of support, and is surrounded by an atmosphere of trust and collaboration.

A complex adaptive systems perspective of health information technology implementation.

PubMed

Keshavjee, Karim; Kuziemsky, Craig; Vassanji, Karim; Ghany, Ahmad

2013-01-01

Implementing health information technology (HIT) is a challenge because of the complexity and multiple interactions that define HIT implementation. Much of the research on HIT implementation is descriptive in nature and has focused on distinct processes such as order entry or decision support. These studies fail to take into account the underlying complexity of the processes, people and settings that are typical of HIT implementations. Complex adaptive systems (CAS) is a promising field that could elucidate the complexity and non-linear interacting issues that are typical in HIT implementation. Initially we sought new models that would enable us to better understand the complex nature of HIT implementation, to proactively identify problem issues that could be a precursor to unintended consequences and to develop new models and new approaches to successful HIT implementations. Our investigation demonstrates that CAS does not provide prediction, but forces us to rethink our HIT implementation paradigms and question what we think we know. CAS provides new ways to conceptualize HIT implementation and suggests new approaches to increasing HIT implementation successes.

Complex hydrides as room-temperature solid electrolytes for rechargeable batteries

NASA Astrophysics Data System (ADS)

de Jongh, P. E.; Blanchard, D.; Matsuo, M.; Udovic, T. J.; Orimo, S.

2016-03-01

A central goal in current battery research is to increase the safety and energy density of Li-ion batteries. Electrolytes nowadays typically consist of lithium salts dissolved in organic solvents. Solid electrolytes could facilitate safer batteries with higher capacities, as they are compatible with Li-metal anodes, prevent Li dendrite formation, and eliminate risks associated with flammable organic solvents. Less than 10 years ago, LiBH4 was proposed as a solid-state electrolyte. It showed a high ionic conductivity, but only at elevated temperatures. Since then a range of other complex metal hydrides has been reported to show similar characteristics. Strategies have been developed to extend the high ionic conductivity of LiBH4 down to room temperature by partial anion substitution or nanoconfinement. The present paper reviews the recent developments in complex metal hydrides as solid electrolytes, discussing in detail LiBH4, strategies towards for fast room-temperature ionic conductors, alternative compounds, and first explorations of implementation of these electrolytes in all-solid-state batteries.

Modeling solvation effects in real-space and real-time within density functional approaches

NASA Astrophysics Data System (ADS)

Delgado, Alain; Corni, Stefano; Pittalis, Stefano; Rozzi, Carlo Andrea

2015-10-01

The Polarizable Continuum Model (PCM) can be used in conjunction with Density Functional Theory (DFT) and its time-dependent extension (TDDFT) to simulate the electronic and optical properties of molecules and nanoparticles immersed in a dielectric environment, typically liquid solvents. In this contribution, we develop a methodology to account for solvation effects in real-space (and real-time) (TD)DFT calculations. The boundary elements method is used to calculate the solvent reaction potential in terms of the apparent charges that spread over the van der Waals solute surface. In a real-space representation, this potential may exhibit a Coulomb singularity at grid points that are close to the cavity surface. We propose a simple approach to regularize such singularity by using a set of spherical Gaussian functions to distribute the apparent charges. We have implemented the proposed method in the Octopus code and present results for the solvation free energies and solvatochromic shifts for a representative set of organic molecules in water.

Modeling solvation effects in real-space and real-time within density functional approaches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delgado, Alain; Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, Calle 30 # 502, 11300 La Habana; Corni, Stefano

2015-10-14

The Polarizable Continuum Model (PCM) can be used in conjunction with Density Functional Theory (DFT) and its time-dependent extension (TDDFT) to simulate the electronic and optical properties of molecules and nanoparticles immersed in a dielectric environment, typically liquid solvents. In this contribution, we develop a methodology to account for solvation effects in real-space (and real-time) (TD)DFT calculations. The boundary elements method is used to calculate the solvent reaction potential in terms of the apparent charges that spread over the van der Waals solute surface. In a real-space representation, this potential may exhibit a Coulomb singularity at grid points that aremore » close to the cavity surface. We propose a simple approach to regularize such singularity by using a set of spherical Gaussian functions to distribute the apparent charges. We have implemented the proposed method in the OCTOPUS code and present results for the solvation free energies and solvatochromic shifts for a representative set of organic molecules in water.« less

Function-Space-Based Solution Scheme for the Size-Modified Poisson-Boltzmann Equation in Full-Potential DFT.

PubMed

Ringe, Stefan; Oberhofer, Harald; Hille, Christoph; Matera, Sebastian; Reuter, Karsten

2016-08-09

The size-modified Poisson-Boltzmann (MPB) equation is an efficient implicit solvation model which also captures electrolytic solvent effects. It combines an account of the dielectric solvent response with a mean-field description of solvated finite-sized ions. We present a general solution scheme for the MPB equation based on a fast function-space-oriented Newton method and a Green's function preconditioned iterative linear solver. In contrast to popular multigrid solvers, this approach allows us to fully exploit specialized integration grids and optimized integration schemes. We describe a corresponding numerically efficient implementation for the full-potential density-functional theory (DFT) code FHI-aims. We show that together with an additional Stern layer correction the DFT+MPB approach can describe the mean activity coefficient of a KCl aqueous solution over a wide range of concentrations. The high sensitivity of the calculated activity coefficient on the employed ionic parameters thereby suggests to use extensively tabulated experimental activity coefficients of salt solutions for a systematic parametrization protocol.

Fast Fenton footprinting: a laboratory-based method for the time-resolved analysis of DNA, RNA and proteins

PubMed Central

Shcherbakova, Inna; Mitra, Somdeb; Beer, Robert H.; Brenowitz, Michael

2006-01-01

‘Footprinting’ describes assays in which ligand binding or structure formation protects polymers such as nucleic acids and proteins from either cleavage or modification; footprinting allows the accessibility of individual residues to be mapped in solution. Equilibrium and time-dependent footprinting links site-specific structural information with thermodynamic and kinetic transitions. The hydroxyl radical (·OH) is a particularly valuable footprinting probe by virtue of it being among the most reactive of chemical oxidants; it reports the solvent accessibility of reactive sites on macromolecules with as fine as a single residue resolution. A novel method of millisecond time-resolved ·OH footprinting has been developed based on the Fenton reaction, Fe(II) + H2O2 → Fe(III) + ·OH + OH−. This method can be implemented in laboratories using widely available three-syringe quench flow mixers and inexpensive reagents to study local changes in the solvent accessibility of DNA, RNA and proteins associated with their biological function. PMID:16582097

Solvent-Assisted Linker Exchange: An Alternative to the De Novo Synthesis of Unattainable Metal-Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karagiaridi, Olga; Bury, Wojciech; Mondloch, Joseph E.

Metal-organic frameworks (MOFs) have gained considerable attention as hybrid materials—in part because of a multitude of potential useful applications, ranging from gas separation to catalysis and light harvesting. Unfortunately, de novo synthesis of MOFs with desirable function–property combinations is not always reliable and may suffer from vagaries such as formation of undesirable topologies, low solubility of precursors, and loss of functionality of the sensitive network components. The recently discovered synthetic approach coined solvent-assisted linker exchange (SALE) constitutes a simple to implement strategy for circumventing these setbacks; its use has already led to the generation of a variety of MOF materialsmore » previously unobtainable by direct synthesis methods. This Review provides a perspective of the achievements in MOF research that have been made possible with SALE and examines the studies that have facilitated the understanding and broadened the scope of use of this invaluable synthetic tool.« less

Applications of micellar enzymology to clean coal technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walsh, C.T.

1990-10-26

This project is designed to develop methods for pre-combustion coal remediation by implementing recent advances in enzyme biochemistry. The novel approach of this study is incorporation of hydrophilic oxidative enzymes in reverse micelles in an organic solvent. Enzymes from commercial sources or microbial extracts are being investigated for their capacity to remove organic sulfur from coal by oxidation of the sulfur groups, splitting of C-S bonds and loss of sulfur as sulfuric acid Dibenzothiophene (DBT) and ethlyphenylsulfide (EPS) are serving as models of organic sulfur-containing components of coal in initial studies. A goal of this project is to define amore » reverse micelle system that optimizes the catalytic activity of enzymes toward desulfurization of model compounds and ultimately coal samples. Among the variables which will be examined are the surfactant, the solvent, the water:surfactant ration and the pH and ionic strength of the aqueous phase. Studies were carried out with HRP, Type I RZ=1.2 and Type VI RZ=3.2 and laccase from Polyporus versicolor. Substrates for HRP assays included hydrogen peroxide, DBT, DBT sulfoxide, and DBT sulfone. Buffers included sodium phosphate. For formation of reverse micelle solutions the surfactant AOT, di(2-ethyl-hexyl)sodium sulphosuccinate, was obtained from Sigma Chemical Co. Isooctant was used as organic solvent. 12 refs., 5 figs., 3 tabs.« less

Calculating pKa values for substituted phenols and hydration energies for other compounds with the first-order Fuzzy-Border continuum solvation model

PubMed Central

Sharma, Ity; Kaminski, George A.

2012-01-01

We have computed pKa values for eleven substituted phenol compounds using the continuum Fuzzy-Border (FB) solvation model. Hydration energies for 40 other compounds, including alkanes, alkenes, alkynes, ketones, amines, alcohols, ethers, aromatics, amides, heterocycles, thiols, sulfides and acids have been calculated. The overall average unsigned error in the calculated acidity constant values was equal to 0.41 pH units and the average error in the solvation energies was 0.076 kcal/mol. We have also reproduced pKa values of propanoic and butanoic acids within ca. 0.1 pH units from the experimental values by fitting the solvation parameters for carboxylate ion carbon and oxygen atoms. The FB model combines two distinguishing features. First, it limits the amount of noise which is common in numerical treatment of continuum solvation models by using fixed-position grid points. Second, it employs either second- or first-order approximation for the solvent polarization, depending on a particular implementation. These approximations are similar to those used for solute and explicit solvent fast polarization treatment which we developed previously. This article describes results of employing the first-order technique. This approximation places the presented methodology between the Generalized Born and Poisson-Boltzmann continuum solvation models with respect to their accuracy of reproducing the many-body effects in modeling a continuum solvent. PMID:22815192

Design and formulation of nano-sized spray dried efavirenz-part I: influence of formulation parameters

NASA Astrophysics Data System (ADS)

Katata, Lebogang; Tshweu, Lesego; Naidoo, Saloshnee; Kalombo, Lonji; Swai, Hulda

2012-11-01

Efavirenz (EFV) is one of the first-line antiretroviral drugs recommended by the World Health Organisation for treating HIV. It is a hydrophobic drug that suffers from low aqueous solubility (4 μg/mL), which leads to a limited oral absorption and low bioavailability. In order to improve its oral bioavailability, nano-sized polymeric delivery systems are suggested. Spray dried polycaprolactone-efavirenz (PCL-EFV) nanoparticles were prepared by the double emulsion method. The Taguchi method, a statistical design with an L8 orthogonal array, was implemented to optimise the formulation parameters of PCL-EFV nanoparticles. The types of sugar (lactose or trehalose), surfactant concentration and solvent (dichloromethane and ethyl acetate) were chosen as significant parameters affecting the particle size and polydispersity index (PDI). Small nanoparticles with an average particle size of less than 254 ± 0.95 nm in the case of ethyl acetate as organic solvent were obtained as compared to more than 360 ± 19.96 nm for dichloromethane. In this study, the type of solvent and sugar were the most influencing parameters of the particle size and PDI. Taguchi method proved to be a quick, valuable tool in optimising the particle size and PDI of PCL-EFV nanoparticles. The optimised experimental values for the nanoparticle size and PDI were 217 ± 2.48 nm and 0.093 ± 0.02.

Effect of solvents extraction on total phenolics and antioxidant activity of extracts from flaxseed (Linum usitatissimum L.).

PubMed

Anwar, Farooq; Przybylski, Roman

2012-01-01

Plant origin food ingredients are the main source of very potent antioxidants. Tocopherols, the main oilseeds natural antioxidants are very potent and when implemented into cell membranes are able to scavenge large number of free radicals. Among plant antioxidants are mainly phenolics, large and diversified group of chemical compounds with different radical scavenging potential. Defatted flaxseed meals were extracted with pure alcohols and its mixture with water. Acquired extracts were analysed for the content of phenolics and flavonoids using colorimetric procedures. Antioxidative capacity was assessed by utilizing: DPPH stable free radicals; inhibition of linoleic acid oxidation and reducing power of components. Investigation was conducted on two different batches of flaxseed, assessing antioxidant capacity of compounds extracted with different polarity solvents and extracts were tested for antioxidant activity with different methods. The highest yield of extraction was achieved with 80% methanol but the extract did not contain the highest amount of phenolics and flavonoids. When 80% ethanol was used for extraction the highest amount of flavonoids was detected and also the best antioxidant capacity. The results clearly showed that utilization of polar solvent enable extraction of significant amounts of phenolics and flavonoids. Those components were the most potent antioxidants present in those extracts. Content of these compounds correlated well with results from applied methods for antioxidant assessment.

Determination of protein folding kinetic types using sequence and predicted secondary structure and solvent accessibility.

PubMed

Zhang, Hua; Zhang, Tuo; Gao, Jianzhao; Ruan, Jishou; Shen, Shiyi; Kurgan, Lukasz

2012-01-01

Proteins fold through a two-state (TS), with no visible intermediates, or a multi-state (MS), via at least one intermediate, process. We analyze sequence-derived factors that determine folding types by introducing a novel sequence-based folding type predictor called FOKIT. This method implements a logistic regression model with six input features which hybridize information concerning amino acid composition and predicted secondary structure and solvent accessibility. FOKIT provides predictions with average Matthews correlation coefficient (MCC) between 0.58 and 0.91 measured using out-of-sample tests on four benchmark datasets. These results are shown to be competitive or better than results of four modern predictors. We also show that FOKIT outperforms these methods when predicting chains that share low similarity with the chains used to build the model, which is an important advantage given the limited number of annotated chains. We demonstrate that inclusion of solvent accessibility helps in discrimination of the folding kinetic types and that three of the features constitute statistically significant markers that differentiate TS and MS folders. We found that the increased content of exposed Trp and buried Leu are indicative of the MS folding, which implies that the exposure/burial of certain hydrophobic residues may play important role in the formation of the folding intermediates. Our conclusions are supported by two case studies.

Synergetic Effects of Alcohol/Water Mixing on the Catalytic Reductive Fractionation of Poplar Wood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Renders, Tom; Van den Bosch, Sander; Vangeel, Thijs

One of the foremost challenges in lignocellulose conversion encompasses the integration of effective lignin valorization in current carbohydrate-oriented biorefinery schemes. Catalytic reductive fractionation (CRF) of lignocellulose offers a technology to simultaneously produce lignin-derived platform chemicals and a carbohydrate-enriched pulp via the combined action of lignin solvolysis and metal-catalyzed hydrogenolysis. Herein, the solvent (composition) plays a crucial role. In this contribution, we study the influence of alcohol/water mixtures by processing poplar sawdust in varying MeOH/water and EtOH/water blends. The results show particular effects that strongly depend on the applied water concentration. Low water concentrations enhance the removal of lignin from themore » biomass, while the majority of the carbohydrates are left untouched (scenario A). Contrarily, high water concentrations favor the solubilization of both hemicellulose and lignin, resulting in a more pure cellulosic residue (scenario B). For both scenarios, an evaluation was made to determine the most optimal solvent composition, based on two earlier introduced empirical efficiency descriptors (denoted LFDE and LFFE). According to these measures, 30 (A) and 70 vol % water (B) showed to be the optimal balance for both MeOH/water and EtOH/water mixtures. This successful implementation of alcohol/water mixtures allows operation under milder processing conditions in comparison to pure alcohol solvents, which is advantageous from an industrial point of view.« less

Achieving Rigorous Accelerated Conformational Sampling in Explicit Solvent.

PubMed

Doshi, Urmi; Hamelberg, Donald

2014-04-03

Molecular dynamics simulations can provide valuable atomistic insights into biomolecular function. However, the accuracy of molecular simulations on general-purpose computers depends on the time scale of the events of interest. Advanced simulation methods, such as accelerated molecular dynamics, have shown tremendous promise in sampling the conformational dynamics of biomolecules, where standard molecular dynamics simulations are nonergodic. Here we present a sampling method based on accelerated molecular dynamics in which rotatable dihedral angles and nonbonded interactions are boosted separately. This method (RaMD-db) is a different implementation of the dual-boost accelerated molecular dynamics, introduced earlier. The advantage is that this method speeds up sampling of the conformational space of biomolecules in explicit solvent, as the degrees of freedom most relevant for conformational transitions are accelerated. We tested RaMD-db on one of the most difficult sampling problems - protein folding. Starting from fully extended polypeptide chains, two fast folding α-helical proteins (Trpcage and the double mutant of C-terminal fragment of Villin headpiece) and a designed β-hairpin (Chignolin) were completely folded to their native structures in very short simulation time. Multiple folding/unfolding transitions could be observed in a single trajectory. Our results show that RaMD-db is a promisingly fast and efficient sampling method for conformational transitions in explicit solvent. RaMD-db thus opens new avenues for understanding biomolecular self-assembly and functional dynamics occurring on long time and length scales.

Estimation of Solvation Quantities from Experimental Thermodynamic Data: Development of the Comprehensive CompSol Databank for Pure and Mixed Solutes

NASA Astrophysics Data System (ADS)

Moine, Edouard; Privat, Romain; Sirjean, Baptiste; Jaubert, Jean-Noël

2017-09-01

The Gibbs energy of solvation measures the affinity of a solute for its solvent and is thus a key property for the selection of an appropriate solvent for a chemical synthesis or a separation process. More fundamentally, Gibbs energies of solvation are choice data for developing and benchmarking molecular models predicting solvation effects. The Comprehensive Solvation—CompSol—database was developed with the ambition to propose very large sets of new experimental solvation chemical-potential, solvation entropy, and solvation enthalpy data of pure and mixed components, covering extended temperature ranges. For mixed compounds, the solvation quantities were generated in infinite-dilution conditions by combining experimental values of pure-component and binary-mixture thermodynamic properties. Three types of binary-mixture properties were considered: partition coefficients, activity coefficients at infinite dilution, and Henry's-law constants. A rigorous methodology was implemented with the aim to select data at appropriate conditions of temperature, pressure, and concentration for the estimation of solvation data. Finally, our comprehensive CompSol database contains 21 671 data associated with 1969 pure species and 70 062 data associated with 14 102 binary mixtures (including 760 solvation data related to the ionic-liquid class of solvents). On the basis of the very large amount of experimental data contained in the CompSol database, it is finally discussed how solvation energies are influenced by hydrogen-bonding association effects.

Development of green betaine-based deep eutectic solvent aqueous two-phase system for the extraction of protein.

PubMed

Li, Na; Wang, Yuzhi; Xu, Kaijia; Huang, Yanhua; Wen, Qian; Ding, Xueqin

2016-05-15

Six kinds of new type of green betaine-based deep eutectic solvents (DESs) have been synthesized. Deep eutectic solvent aqueous two-phase systems (DES-ATPS) were established and successfully applied in the extraction of protein. Betaine-urea (Be-U) was selected as the suitable extractant. Single factor experiments were carried out to determine the optimum conditions of the extraction process, such as the salt concentration, the mass of DES, the separation time, the amount of protein, the temperature and the pH value. The extraction efficiency could achieve to 99.82% under the optimum conditions. Mixed sample and practical sample analysis were discussed. The back extraction experiment was implemented and the back extraction efficiency could reach to 32.66%. The precision experiment, repeatability experiment and stability experiment were investigated. UV-vis, FT-IR and circular dichroism (CD) spectra confirmed that the conformation of protein was not changed during the process of extraction. The mechanisms of extraction were researched by dynamic light scattering (DLS), the measurement of the conductivity and transmission electron microscopy (TEM). DES-protein aggregates and embraces phenomenon play considerable roles in the separation process. All of these results indicated that betaine-based DES-ATPS may provide a potential substitute new method for the separation of proteins. Copyright © 2016 Elsevier B.V. All rights reserved.

78 FR 35117 - Orphan Drug Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-12

...The Food and Drug Administration (FDA) is issuing final regulations amending the 1992 Orphan Drug Regulations issued to implement the Orphan Drug Act. These amendments are intended to clarify regulatory provisions and make minor improvements to address issues that have arisen since those regulations were issued.

Campus and Community Coalitions. Issues in Prevention

ERIC Educational Resources Information Center

Higher Education Center for Alcohol, Drug Abuse, and Violence Prevention, 2012

2012-01-01

This issue of "Issues in Prevention" focuses on campus and community coalitions. This issue contains the following articles: (1) Campus and Community Coalitions: Implementing Environmental Prevention Strategies (John D. Clapp); (2) Campus Brief: University of Rhode Island; (3) International Town & Gown Association; (4) Q&A With…

Phytoremediation and innovative strategies for specialized remedial actions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alleman, B.C.; Leeson, A.

1999-01-01

Phytoremediation is a site remediation strategy whose time seems to have come in the past few years, with field implementations taking place in a host of applications. From laboratory studies on plant uptake to full-scale phytoremediation treatment strategies, this volume covers the use of plants to treat contaminants such as hydrocarbons, metals, pesticides, perchlorate, and chlorinated solvents. In addition to the phytoremediation studies, this volume also covers specialized remediation approaches such as sequential anaerobic/aerobic in situ treatment, membrane bioreactors, and Fenton's reagent oxidation.

Phytoremediation and innovative strategies for specialized remedial actions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alleman, B.C.; Leeson, A.

1999-11-01

Phytoremediation is a site remediation strategy whose time seems to have come in the past few years, with field implementations taking place in a host of applications. From laboratory studies on plant uptake to full-scale phytoremediation treatment strategies, this volume covers the use of plants to treat contaminants such as hydrocarbons, metals, pesticides, perchlorate, and chlorinated solvents. In addition to the phytoremediation studies, this volume also covers specialized remediation approaches such as sequential anaerobic/aerobic in situ treatment, membrane bioreactors, and Fenton`s reagent oxidation.

Phytoremediation and innovative strategies for specialized remedial applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alleman, B.C.; Leeson, A.

1999-10-01

Phytoremediation is a site remediation strategy whose time seems to have come in the past few years, with field implementations taking place in a host of applications. From laboratory studies on plant uptake to full-scale phytoremediation treatment strategies, this volume covers the use of plants to treat contaminants such as hydrocarbons, metals, pesticides, perchlorate, and chlorinated solvents. In addition to the phytoremediation studies, this volume also covers specialized remediation approaches such as sequential anaerobic/aerobic in situ treatment, membrane bioreactors, and Fenton`s reagent oxidation.

Jackfruit (Artocarpus heterophyllus lamk) wood waste as a textile natural dye by micowave-assisted extraction method

NASA Astrophysics Data System (ADS)

Qadariyah, Lailatul; Gala, Selfina; Widoretno, Dhaniar Rulandri; Kunhermanti, Delita; Bhuana, Donny S.; Sumarno, Mahfud, Mahfud

2017-05-01

The development of technology causes most of textile industries in Indonesia prefer to use synthetic dyes in the fabric dyeing process. In fact, synthetic dyes is able to have negative effect since it is is toxic to the health of workers and environment. To resolve this issues, one way to do is to use natural dyes. One of untapped potential in Indonesia is wood waste of jackfruit from furniture industry. Jackfruit wood itself containing dyestuffs which gives yellow color pigment so that it can be used as an alternative source of natural dyes. The purpose of this research is to study the effect of extraction time, mass to solvent volume ratio, and microwave power to yield of dyes. The extract of dye analyzed by UV-Visible Spectrophotometer and GC-MS, along the coloring and endurance tests of natural dyes on fabric and compare it with synthetic dyes. In this research, material is going to be extracted is the wood of jackfruit (Artocarpus heterophyllus lamk) with material size between 35 mesh - 60 mesh. The extraction process is done by using ethanol 96%. Extraction using MAE is carried out at the ratio of materials to solvent of 0,02-0,1 g/mL, the microwave power of 100-800 Watt, and the extraction time of 10-90 minutes. The conclusion is at microwave power of 400 Watt, material to solvent ratio of the 0,02 g/mL, the yield is 3,39% while at microwave power of 600 Watt, material to solvent ratio of the 0,02 g/mL, the yield is 3,67% with extraction time of 30 minutes. The highest recovery from ethanol 96% solvent is 60,41%. The result of UV-Vis Spectrophotometry and GC-MS test show that there is a chromophore compound in the extract of natural dye. The test results show the natural dyes of jackfruit wood can be used to coloring on the textile because it can gives staining result permanently.

Interagency Collaborative Team Model for Capacity Building to Scale-Up Evidence-Based Practice

PubMed Central

Hurlburt, Michael; Aarons, Gregory A; Fettes, Danielle; Willging, Cathleen; Gunderson, Lara; Chaffin, Mark J

2015-01-01

Background System-wide scale up of evidence-based practice (EBP) is a complex process. Yet, few strategic approaches exist to support EBP implementation and sustainment across a service system. Building on the Exploration, Preparation, Implementation, and Sustainment (EPIS) implementation framework, we developed and are testing the Interagency Collaborative Team (ICT) process model to implement an evidence-based child neglect intervention (i.e., SafeCare®) within a large children’s service system. The ICT model emphasizes the role of local agency collaborations in creating structural supports for successful implementation. Methods We describe the ICT model and present preliminary qualitative results from use of the implementation model in one large scale EBP implementation. Qualitative interviews were conducted to assess challenges in building system, organization, and home visitor collaboration and capacity to implement the EBP. Data collection and analysis centered on EBP implementation issues, as well as the experiences of home visitors under the ICT model. Results Six notable issues relating to implementation process emerged from participant interviews, including: (a) initial commitment and collaboration among stakeholders, (b) leadership, (c) communication, (d) practice fit with local context, (e) ongoing negotiation and problem solving, and (f) early successes. These issues highlight strengths and areas for development in the ICT model. Conclusions Use of the ICT model led to sustained and widespread use of SafeCare in one large county. Although some aspects of the implementation model may benefit from enhancement, qualitative findings suggest that the ICT process generates strong structural supports for implementation and creates conditions in which tensions between EBP structure and local contextual variations can be resolved in ways that support the expansion and maintenance of an EBP while preserving potential for public health benefit. PMID:27512239

Interagency Collaborative Team Model for Capacity Building to Scale-Up Evidence-Based Practice.

PubMed

Hurlburt, Michael; Aarons, Gregory A; Fettes, Danielle; Willging, Cathleen; Gunderson, Lara; Chaffin, Mark J

2014-04-01

System-wide scale up of evidence-based practice (EBP) is a complex process. Yet, few strategic approaches exist to support EBP implementation and sustainment across a service system. Building on the Exploration, Preparation, Implementation, and Sustainment (EPIS) implementation framework, we developed and are testing the Interagency Collaborative Team (ICT) process model to implement an evidence-based child neglect intervention (i.e., SafeCare®) within a large children's service system. The ICT model emphasizes the role of local agency collaborations in creating structural supports for successful implementation. We describe the ICT model and present preliminary qualitative results from use of the implementation model in one large scale EBP implementation. Qualitative interviews were conducted to assess challenges in building system, organization, and home visitor collaboration and capacity to implement the EBP. Data collection and analysis centered on EBP implementation issues, as well as the experiences of home visitors under the ICT model. Six notable issues relating to implementation process emerged from participant interviews, including: (a) initial commitment and collaboration among stakeholders, (b) leadership, (c) communication, (d) practice fit with local context, (e) ongoing negotiation and problem solving, and (f) early successes. These issues highlight strengths and areas for development in the ICT model. Use of the ICT model led to sustained and widespread use of SafeCare in one large county. Although some aspects of the implementation model may benefit from enhancement, qualitative findings suggest that the ICT process generates strong structural supports for implementation and creates conditions in which tensions between EBP structure and local contextual variations can be resolved in ways that support the expansion and maintenance of an EBP while preserving potential for public health benefit.

Institutional and policy issues in adopting advanced public transportation systems technology

DOT National Transportation Integrated Search

1995-09-01

This project, Institutional and Policy Issues in Adopting Advanced Public Transportation Systems Technologies, aimed to study critical mass transportation issues associated with the implementation of intelligent transportation systems (ITS) in the no...

Study of Issues Related to the Implementation of Computer Technology in Schools. Final Report, July, 1981. Technical Report No. 2.

ERIC Educational Resources Information Center

Sheingold, Karen; And Others

This study examined ways in which microcomputers are used in schools and the complex issues that surround their implementation. Three fictional geographically distinct school districts with a diversity of microcomputer applications at both the elementary and secondary levels were studied: Salerno, a large southern city; Granite, a midwestern city;…

75 FR 50845 - Privacy Act of 1974: Implementation of Exemptions; Department of Homeland Security/ALL-027 The...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-18

... Policy, Department of Homeland Security, Washington, DC 20528. For privacy issues please contact: Mary...;Prices of new books are listed in the first FEDERAL REGISTER issue of each #0;week. #0; #0; #0; #0;#0...] Privacy Act of 1974: Implementation of Exemptions; Department of Homeland Security/ALL--027 The History of...

75 FR 67909 - Privacy Act of 1974: Implementation of Exemptions; Department of Homeland Security Office of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-04

... facsimile (202) 254-4299. For privacy issues please contact: Mary Ellen Callahan (703-235-0780), Chief...;Prices of new books are listed in the first FEDERAL REGISTER issue of each #0;week. #0; #0; #0; #0;#0...] Privacy Act of 1974: Implementation of Exemptions; Department of Homeland Security Office of the Inspector...

Performance issues for domain-oriented time-driven distributed simulations

NASA Technical Reports Server (NTRS)

Nicol, David M.

1987-01-01

It has long been recognized that simulations form an interesting and important class of computations that may benefit from distributed or parallel processing. Since the point of parallel processing is improved performance, the recent proliferation of multiprocessors requires that we consider the performance issues that naturally arise when attempting to implement a distributed simulation. Three such issues are: (1) the problem of mapping the simulation onto the architecture, (2) the possibilities for performing redundant computation in order to reduce communication, and (3) the avoidance of deadlock due to distributed contention for message-buffer space. These issues are discussed in the context of a battlefield simulation implemented on a medium-scale multiprocessor message-passing architecture.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This report contains papers on the following topics: NREN Security Issues: Policies and Technologies; Layer Wars: Protect the Internet with Network Layer Security; Electronic Commission Management; Workflow 2000 - Electronic Document Authorization in Practice; Security Issues of a UNIX PEM Implementation; Implementing Privacy Enhanced Mail on VMS; Distributed Public Key Certificate Management; Protecting the Integrity of Privacy-enhanced Electronic Mail; Practical Authorization in Large Heterogeneous Distributed Systems; Security Issues in the Truffles File System; Issues surrounding the use of Cryptographic Algorithms and Smart Card Applications; Smart Card Augmentation of Kerberos; and An Overview of the Advanced Smart Card Access Control System.more » Selected papers were processed separately for inclusion in the Energy Science and Technology Database.« less

Assessment of the Impact of a New Guanidine Suppressor In NGS on F/H Laboratory Analyses For DWPF and Saltstone MCU Transfers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.

2013-04-29

Implementation of the Next Generation Solvent (NGS) in the Modular Caustic-Side Solvent Extraction Unit (MCU) will now proceed with a new suppressor compound, 1,2,3-tris(3,7-dimethyloctyl)guanidine (TiDG), replacing the originally planned suppressor for NGS, 1,3-dicyclohexyl-2-(11-methyldodecyl) guanidine (DCiTG). The Savannah River National Laboratory (SRNL) was tasked with evaluating the potential impact to F/H Laboratory analyses supporting the Defense Waste Processing Facility (DWPF) Waste Acceptance Criteria (WAC) used to qualify transfers of MCU Strip Effluent (SE) into the facility and the Saltstone WAC used to qualify transfers of Tank 50 containing Decontaminated Salt Solution (DSS) from MCU into Saltstone. This assigned scope is coveredmore » by a Task Technical and Quality Assurance Plan (TTQAP). Previous impact evaluations were conducted when the DCiTG suppressor was planned for NGS and concluded that there was no impact to either the determination of MCU SE pH nor the analysis of Isopar® L carryover in the MCU SE and DSS streams. SRNL reported on this series of cross-check studies between the SRNL and F/H Laboratories. The change in suppressor from DCiTG to TiDG in the NGS should not impact the measurement of Isopar® L or pH in SE or DSS necessary to satisfy DWPF and Saltstone WAC (Tank 50) criteria, respectively. A statistical study of the low bias observed in Isopar® L measurements in both SRNL and F/H Laboratories may be necessary now that the final NGS composition is fixed in order to quantify the low bias so that a proper correction can be applied to measurements critical to the DWPF and Saltstone WACs. Depending upon the final DWPF WAC requirement put in place for SE pH, it could become necessary to implement an alternative ICP-AES measurement of boron. The current blended solvent system testing in SRNL should address any impacts to Isopar® L carryover into either the DSS or the SE. It is recommended that SRNL monitor the current blended solvent work underway with simulants in SRNL as well as any DWPF CPC testing done with the new SE stream to ascertain whether any need develops that could result in modification of any currently planned F/H Laboratory testing protocols.« less

Preferential solvation and solvation shell composition of free base and protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin in aqueous organic mixed solvents

NASA Astrophysics Data System (ADS)

Farajtabar, Ali; Jaberi, Fatemeh; Gharib, Farrokh

2011-12-01

The solvatochromic properties of the free base and the protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) were studied in pure water, methanol, ethanol (protic solvents), dimethylsulfoxide, DMSO, (non-protic solvent), and their corresponding aqueous-organic binary mixed solvents. The correlation of the empirical solvent polarity scale ( ET) values of TPPS with composition of the solvents was analyzed by the solvent exchange model of Bosch and Roses to clarify the preferential solvation of the probe dyes in the binary mixed solvents. The solvation shell composition and the synergistic effects in preferential solvation of the solute dyes were investigated in terms of both solvent-solvent and solute-solvent interactions and also, the local mole fraction of each solvent composition was calculated in cybotactic region of the probe. The effective mole fraction variation may provide significant physico-chemical insights in the microscopic and molecular level of interactions between TPPS species and the solvent components and therefore, can be used to interpret the solvent effect on kinetics and thermodynamics of TPPS. The obtained results from the preferential solvation and solvent-solvent interactions have been successfully applied to explain the variation of equilibrium behavior of protonation of TPPS occurring in aqueous organic mixed solvents of methanol, ethanol and DMSO.

Ethical issues in the development and implementation of nutrition-related public health policies and interventions: A scoping review

PubMed Central

Peña-Rosas, Juan Pablo; Saxena, Abha; Zamora, Gerardo

2017-01-01

Background The limited integration of ethics in nutrition-related public health policies and interventions is one major concern for those who have the task of implementing them. Ethical challenges that are overlooked during the development of such interventions could raise serious ethical issues during their implementation and even after. As a result, these decision makers need technical support and ethical guidance for adaptation of interventions to local (cultural, social, economic, etc.) contexts. Aim The goal of this scoping review is to delineate and “map” the range of ethical issues in nutrition-related public health interventions, as well as the range of the various fields in which they may arise. Methods A scoping review of empirical research and conceptual literature was conducted following the framework of Arksey and O’Malley. Searches using PubMed with Medical Subject Headings (MeSH) categories and Advanced Search Builder as well as in the Global Health Library were performed. The final sample consists of 169 publications. Results The ethics of public health prevention or treatment of obesity and non-communicable diseases is the most explicitly and frequently discussed subject. In comparison, ethical issues raised by public health interventions in the fields of undernutrition, breastfeeding, vitamin/mineral supplementation and food fortification, food security, food sustainability and food safety are addressed in a lower proportion of the sample. The results illustrate the various natures, types, and scopes of existing public health nutrition-related interventions, and the various ethical issues that may be raised by these interventions, in addition to the numerous and different contexts in which they may be implemented. Discussion The ethical issues faced in the development and implementation of nutrition-related public health interventions are varied and cannot be equated with, nor generalized about, when dealing with specific activities in this field. More importantly, these ethical issues cannot be managed without a careful consideration for the complexity of contexts in which nutrition-related interventions are expected to be implemented. These interventions engage a variety of actors with diverse perspectives and interests. We discuss these challenges and also comment on the importance of considering ethical impacts in the monitoring and evaluation of such interventions. Conclusion General ethical frameworks or recommendations–although useful–cannot be expected to provide policy makers, implementators and other public health personnel with sufficient practical ethical guidance as they cannot consider and anticipate the particularities of all specific nutrition-related public health interventions and the complexity of the contexts in which they are implemented. Further research is needed in order to develop more targeted ethical frameworks. PMID:29073186

Solvent wash solution

DOEpatents

Neace, J.C.

1984-03-13

A process is claimed for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 vol % of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Solvent wash solution

DOEpatents

Neace, James C.

1986-01-01

Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Implementation science approaches for integrating eHealth research into practice and policy.

PubMed

Glasgow, Russell E; Phillips, Siobhan M; Sanchez, Michael A

2014-07-01

To summarize key issues in the eHealth field from an implementation science perspective and to highlight illustrative processes, examples and key directions to help more rapidly integrate research, policy and practice. We present background on implementation science models and emerging principles; discuss implications for eHealth research; provide examples of practical designs, measures and exemplar studies that address key implementation science issues; and make recommendations for ways to more rapidly develop and test eHealth interventions as well as future research, policy and practice. The pace of eHealth research has generally not kept up with technological advances, and many of our designs, methods and funding mechanisms are incapable of providing the types of rapid and relevant information needed. Although there has been substantial eHealth research conducted with positive short-term results, several key implementation and dissemination issues such as representativeness, cost, unintended consequences, impact on health inequities, and sustainability have not been addressed or reported. Examples of studies in several of these areas are summarized to demonstrate this is possible. eHealth research that is intended to translate into policy and practice should be more contextual, report more on setting factors, employ more responsive and pragmatic designs and report results more transparently on issues important to potential adopting patients, clinicians and organizational decision makers. We outline an alternative development and assessment model, summarize implementation science findings that can help focus attention, and call for different types of more rapid and relevant research and funding mechanisms. Published by Elsevier Ireland Ltd.

Issues in Implementing a Structured Problem-Based Learning Strategy in a Volcano Unit: A Case Study

ERIC Educational Resources Information Center

Lee, Hyunju; Bae, Sungah

2008-01-01

The purpose of this study was to understand how an 8th grade science class used a structured problem-based learning (PBL) strategy to study volcanoes and to discuss some of the issues that science teachers might encounter when designing and implementing the PBL strategy. This study took place at Collins Middle School, which is located in a…

Privacy-Driven Design of Learning Analytics Applications: Exploring the Design Space of Solutions for Data Sharing and Interoperability

ERIC Educational Resources Information Center

Hoel, Tore; Chen, Weiqin

2016-01-01

Studies have shown that issues of privacy, control of data, and trust are essential to implementation of learning analytics systems. If these issues are not addressed appropriately, systems will tend to collapse due to a legitimacy crisis, or they will not be implemented in the first place due to resistance from learners, their parents, or their…

An intervention to help community-based organizations implement an evidence-based HIV prevention intervention: the Mpowerment Project technology exchange system.

PubMed

Kegeles, Susan M; Rebchook, Gregory; Pollack, Lance; Huebner, David; Tebbetts, Scott; Hamiga, John; Sweeney, David; Zovod, Benjamin

2012-03-01

Considerable resources have been spent developing and rigorously testing HIV prevention intervention models, but such models do not impact the AIDS pandemic unless they are implemented effectively by community-based organizations (CBOs) and health departments. The Mpowerment Project (MP) is being implemented by CBOs around the U.S. It is a multilevel, evidence-based HIV prevention program for young gay/bisexual men that targets individual, interpersonal, social, and structural issues by using empowerment and community mobilization methods. This paper discusses the development of an intervention to help CBOs implement the MP called the Mpowerment Project Technology Exchange System (MPTES); CBOs' uptake, utilization and perceptions of the MPTES components; and issues that arose during technical assistance. The seven-component MPTES was provided to 49 CBOs implementing the MP that were followed longitudinally for up to two years. Except for the widely used program manual, other program materials were used early in implementing the MP and then their use declined. In contrast, once technical assistance was proactively provided, its usage remained constant over time, as did requests for technical assistance. CBOs expressed substantial positive feedback about the MPTES, but felt that it needs more focus on diversity issues, describing real world implementation approaches, and providing guidance on how to adapt the MP to diverse populations.

International and domestic regulator issues facing the Canadian MSAT system

NASA Technical Reports Server (NTRS)

Bahman, Azarbar; Langlois, Jacques R.; Frank, Christopher J.

1988-01-01

International and domestic regulatory issues which affect the implementation of a mobile satellite system (MSAT) over North America are addressed. WARC-MOB-87, MSAT frequency co-ordination, frequency sharing and key Canadian domestic issues are discussed.

Modeling Optical Spectra of Large Organic Systems Using Real-Time Propagation of Semiempirical Effective Hamiltonians.

PubMed

Ghosh, Soumen; Andersen, Amity; Gagliardi, Laura; Cramer, Christopher J; Govind, Niranjan

2017-09-12

We present an implementation of a time-dependent semiempirical method (INDO/S) in NWChem using real-time (RT) propagation to address, in principle, the entire spectrum of valence electronic excitations. Adopting this model, we study the UV/vis spectra of medium-sized systems such as P3B2 and f-coronene, and in addition much larger systems such as ubiquitin in the gas phase and the betanin chromophore in the presence of two explicit solvents (water and methanol). RT-INDO/S provides qualitatively and often quantitatively accurate results when compared with RT- TDDFT or experimental spectra. Even though we only consider the INDO/S Hamiltonian in this work, our implementation provides a framework for performing electron dynamics in large systems using semiempirical Hartree-Fock Hamiltonians in general.

Modeling Optical Spectra of Large Organic Systems Using Real-Time Propagation of Semiempirical Effective Hamiltonians

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Soumen; Andersen, Amity; Gagliardi, Laura

2017-08-16

We present an implementation of a time-dependent semiempirical method (INDO/S) in NWChem using real-time (RT) propagation to address, in principle, the entire spectrum of valence electronic excitations. Adopting this model, we study the UV-visible spectra of medium-sized systems like P3B2, f-coronene, and in addition much larger systems like ubiquitin in the gas phase and the betanin chromophore in the presence of two explicit solvents (water and methanol). RT-INDO/S provides qualitatively and indeed often quantitatively accurate results when compared with RT- TDDFT or experimental spectra. While demonstrated here for INDO/S in particular, our implementation provides a framework for performing electron dynamicsmore » in large systems using semiempirical Hartree-Fock (HF) Hamiltonians in general.« less

A comparative study of Averrhoabilimbi extraction method

NASA Astrophysics Data System (ADS)

Zulhaimi, H. I.; Rosli, I. R.; Kasim, K. F.; Akmal, H. Muhammad; Nuradibah, M. A.; Sam, S. T.

2017-09-01

In recent year, bioactive compound in plant has become a limelight in the food and pharmaceutical market, leading to research interest to implement effective technologies for extracting bioactive substance. Therefore, this study is focusing on extraction of Averrhoabilimbi by different extraction technique namely, maceration and ultrasound-assisted extraction. Fewplant partsof Averrhoabilimbiweretaken as extraction samples which are fruits, leaves and twig. Different solvents such as methanol, ethanol and distilled water were utilized in the process. Fruit extractsresult in highest extraction yield compared to other plant parts. Ethanol and distilled water have significant role compared to methanol in all parts and both extraction technique. The result also shows that ultrasound-assisted extraction gave comparable result with maceration. Besides, the shorter period on extraction process gives useful in term of implementation to industries.

HippDB: a database of readily targeted helical protein-protein interactions.

PubMed

Bergey, Christina M; Watkins, Andrew M; Arora, Paramjit S

2013-11-01

HippDB catalogs every protein-protein interaction whose structure is available in the Protein Data Bank and which exhibits one or more helices at the interface. The Web site accepts queries on variables such as helix length and sequence, and it provides computational alanine scanning and change in solvent-accessible surface area values for every interfacial residue. HippDB is intended to serve as a starting point for structure-based small molecule and peptidomimetic drug development. HippDB is freely available on the web at http://www.nyu.edu/projects/arora/hippdb. The Web site is implemented in PHP, MySQL and Apache. Source code freely available for download at http://code.google.com/p/helidb, implemented in Perl and supported on Linux. arora@nyu.edu.

Implementation of Socioscientific Issues Instruction to Fostering Students’ Decision Making Based Gender on Environmental Pollution

NASA Astrophysics Data System (ADS)

Rizal, H. P.; Siahaan, P.; Yuliani, G.

2017-02-01

The purpose of this study was to investigate the implementation socioscientific issues (SSI) instruction to examine students’ decision making based gender. Selection of environmental problem based on the consideration this issue has potential to evaluate from various scientific disciplines and may initiate to make decision. The participant was students grade VII in South Sulawesi. Pre experiment method was utilized in study with one group pre-test and post-test design. The instrument used in this study comprised of open-ended question, observation sheets for group discussion, sheet for interview and observation sheet of implementation instruction in class. The result indicated that instruction has been implemented successfully. It was found that pre-test and post-test was fostered with N-gain for male and female in medium category. Based on independent t test was found there was no difference improvement of decision making between male and female students. The group showed there was no difference between male group and female group, but a significant difference was noted in mix group. Students and teacher give positive response to the implementation of instruction. It is concluded that science instruction based SSI can be implemented to foster male and female decision making by forming group discussion.

Repairable chip bonding/interconnect process

DOEpatents

Bernhardt, Anthony F.; Contolini, Robert J.; Malba, Vincent; Riddle, Robert A.

1997-01-01

A repairable, chip-to-board interconnect process which addresses cost and testability issues in the multi-chip modules. This process can be carried out using a chip-on-sacrificial-substrate technique, involving laser processing. This process avoids the curing/solvent evolution problems encountered in prior approaches, as well is resolving prior plating problems and the requirements for fillets. For repairable high speed chip-to-board connection, transmission lines can be formed on the sides of the chip from chip bond pads, ending in a gull wing at the bottom of the chip for subsequent solder.

Mixed organic compound-ionic liquid electrolytes for lithium battery electrolyte systems

NASA Astrophysics Data System (ADS)

Montanino, M.; Moreno, M.; Carewska, M.; Maresca, G.; Simonetti, E.; Lo Presti, R.; Alessandrini, F.; Appetecchi, G. B.

2014-12-01

The thermal, transport, rheological and flammability properties of electrolyte mixtures, proposed for safer lithium-ion battery systems, were investigated as a function of the mole composition. The blends were composed of a lithium salt (LiTFSI), organic solvents (namely EC, DEC) and an ionic liquid (PYR13TFSI). The main goal is to combine the fast ion transport properties of the organic compounds with the safe issues of the non-flammable and non-volatile ionic liquids. Preliminary tests in batteries have evidenced cycling performance approaching that observed in commercial organic electrolytes.

New Yellow Synergist for Stable Pigment Dispersion of Inkjet Ink.

PubMed

Song, Gihyun; Lee, Hayoon; Jung, Hyocheol; Kang, Seokwoo; Park, Jongwook

2018-02-01

Minimizing ink droplet and self-dispersed pigment mixture are becoming hot issues for high resolution of inkjet printing. New synergist including sulfonic acid group of PY-74 was suggested and synthesized. Pigment itself did not show water solubility but new synergist, SY-11 exhibited good solubility in water and organic solvents such as DMSO and DMF. When aqueous pigment ink was prepared with SY-11, storage stability of the ink has been remained for 7 days under periodically repeated heating and cooling conditions. Particle size of formulated ink was around 150 nm.

25 CFR 275.4 - Implementing regulations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 25 Indians 1 2011-04-01 2011-04-01 false Implementing regulations. 275.4 Section 275.4 Indians... ACT PROGRAM STAFFING § 275.4 Implementing regulations. Regulations to implement section 105 of the Act will be issued by the Civil Service Commission. The regulations will cover the situations described in...

25 CFR 275.4 - Implementing regulations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Implementing regulations. 275.4 Section 275.4 Indians... ACT PROGRAM STAFFING § 275.4 Implementing regulations. Regulations to implement section 105 of the Act will be issued by the Civil Service Commission. The regulations will cover the situations described in...

Implementing and Sustaining School Improvement. The Informed Educator Series

ERIC Educational Resources Information Center

Protheroe, Nancy

2011-01-01

This "Informed Educator" examines research-proven strategies for implementing and sustaining school improvement by looking at the key elements of the process, enabling conditions for improvement, issues of school culture, and implementation. It also looks at school turnarounds and how to sustain school improvement once reforms are implemented.

Going digital: a checklist in preparing for hospital-wide electronic medical record implementation and digital transformation.

PubMed

Scott, Ian A; Sullivan, Clair; Staib, Andrew

2018-05-24

Objective In an era of rapid digitisation of Australian hospitals, practical guidance is needed in how to successfully implement electronic medical records (EMRs) as both a technical innovation and a major transformative change in clinical care. The aim of the present study was to develop a checklist that clearly and comprehensively defines the steps that best prepare hospitals for EMR implementation and digital transformation. Methods The checklist was developed using a formal methodological framework comprised of: literature reviews of relevant issues; an interactive workshop involving a multidisciplinary group of digital leads from Queensland hospitals; a draft document based on literature and workshop proceedings; and a review and feedback from senior clinical leads. Results The final checklist comprised 19 questions, 13 related to EMR implementation and six to digital transformation. Questions related to the former included organisational considerations (leadership, governance, change leaders, implementation plan), technical considerations (vendor choice, information technology and project management teams, system and hardware alignment with clinician workflows, interoperability with legacy systems) and training (user training, post-go-live contingency plans, roll-out sequence, staff support at point of care). Questions related to digital transformation included cultural considerations (clinically focused vision statement and communication strategy, readiness for change surveys), management of digital disruption syndromes and plans for further improvement in patient care (post-go-live optimisation of digital system, quality and benefit evaluation, ongoing digital innovation). Conclusion This evidence-based, field-tested checklist provides guidance to hospitals planning EMR implementation and separates readiness for EMR from readiness for digital transformation. What is known about the topic? Many hospitals throughout Australia have implemented, or are planning to implement, hospital wide electronic medical records (EMRs) with varying degrees of functionality. Few hospitals have implemented a complete end-to-end digital system with the ability to bring about major transformation in clinical care. Although the many challenges in implementing EMRs have been well documented, they have not been incorporated into an evidence-based, field-tested checklist that can practically assist hospitals in preparing for EMR implementation as both a technical innovation and a vehicle for major digital transformation of care. What does this paper add? This paper outlines a 19-question checklist that was developed using a formal methodological framework comprising literature review of relevant issues, proceedings from an interactive workshop involving a multidisciplinary group of digital leads from hospitals throughout Queensland, including three hospitals undertaking EMR implementation and one hospital with complete end-to-end EMR, and review of a draft checklist by senior clinical leads within a statewide digital healthcare improvement network. The checklist distinguishes between issues pertaining to EMR as a technical innovation and EMR as a vehicle for digital transformation of patient care. What are the implications for practitioners? Successful implementation of a hospital-wide EMR requires senior managers, clinical leads, information technology teams and project management teams to fully address key operational and strategic issues. Using an issues checklist may help prevent any one issue being inadvertently overlooked or underemphasised in the planning and implementation stages, and ensure the EMR is fully adopted and optimally used by clinician users in an ongoing digital transformation of care.

Comparative study of generalized born models: Born radii and peptide folding.

PubMed

Zhu, Jiang; Alexov, Emil; Honig, Barry

2005-02-24

In this study, we have implemented four analytical generalized Born (GB) models and investigated their performance in conjunction with the GROMOS96 force field. The four models include that of Still and co-workers, the HCT model of Cramer, Truhlar, and co-workers, a modified form of the AGB model of Levy and co-workers, and the GBMV2 model of Brooks and co-workers. The models were coded independently and implemented in the GROMOS software package and in TINKER. They were compared in terms of their ability to reproduce the results of Poisson-Boltzmann (PB) calculations and in their performance in the ab initio peptide folding of two peptides, one that forms a beta-hairpin in solution and one that forms an alpha-helix. In agreement with previous work, the GBMV2 model is most successful in reproducing PB results while the other models tend to underestimate the effective Born radii of buried atoms. In contrast, stochastic dynamics simulations on the folding of the two peptides, the C-terminus beta-hairpin of the B1 domain of protein G and the alanine-based alpha-helical peptide 3K(I), suggest that the simpler GB models are more effective in sampling conformational space. Indeed, the Still model used in conjunction with the GROMOS96 force field is able to fold the hairpin peptide to a native-like structure without the benefit of enhanced sampling techniques. This is due in part to the properties of the united-atom GROMOS96 force field which appears to be more flexible, and hence to sample more efficiently, than force fields such as OPLSAA. Our results suggest a general strategy which involves using different combinations of force fields and solvent models in different applications, for example, using GROMOS96 and a simple GB model in sampling and OPLSAA and a more accurate GB model in refinement. The fact that various methods have been implemented in a unified way should facilitate the testing and subsequent use of different methods to evaluate conformational free energies in different applications. Our results also bear on some general issues involved in peptide folding and structure prediction which are addressed in the Discussion.

Strategies for teaching object-oriented concepts with Java

NASA Astrophysics Data System (ADS)

Sicilia, Miguel-Ángel

2006-03-01

A considerable amount of experiences in teaching object-oriented concepts using the Java language have been reported to date, some of which describe language pitfalls and concrete learning difficulties. In this paper, a number of additional issues that have been experienced as difficult for students to master, along with approaches intended to overcome them, are addressed. Concretely, practical issues regarding associations, interfaces, genericity and exceptions are described. These issues suggest that more emphasis is required on presenting Java programs as derivations of conceptual models, in order to guarantee that a thorough design of the object structure actually precedes implementation issues. In addition, common student misunderstandings about the uses of interfaces and exceptions point to the necessity of introducing both specific design philosophies and also a clear distinction between design-for-reuse and more specific implementation issues.

Acetone improves the topographical homogeneity of liquid phase exfoliated few-layer black phosphorus flakes.

PubMed

Gomez Perez, Juan; Konya, Zoltan; Kukovecz, Akos

2018-06-12

Liquid phase exfoliation of 2D materials has issues related to the sorption of the solvent, the oxidation of the sample during storage, and the topographical inhomogeneity of the exfoliated material. N-methyl-2-pyrrolidone (NMP), a common solvent for black phosphorus (BP) exfoliation, has additional drawbacks like the formation of by-products during sonication and poor solvent volatility. Here we demonstrate an improvement in the topographical homogeneity (i.e. thickness and lateral dimensions) of NMP-exfoliated BP flakes after resuspension in acetone. The typical size of monolayers and bilayers stabilised in acetone was 99.8±27.4 nm and 159.1±57 nm, respectively. These standard deviations represent a threefold improvement over those of the NMP-exfoliated originals. Phosphorene can also be exfoliated directly in acetone by very long ultrasonication. The product suspension enjoys the same dimensional homogeneity benefits, which confirms that this effect is an intrinsic property of the acetone-BP system. The quality and stability of the exfoliated flakes was checked by XRD, TEM, electron diffraction and Raman spectroscopy. Thermal expansion coefficients of the A1g, B2g and A2g Raman modes were calculated for drop-casted samples as -0.01828 cm-1/K, -0.03056 cm-1/K and -0.03219 cm-1/K, respectively. The flakes withstand 20 minutes in O2 flow at 373 K without lattice distortion. . © 2018 IOP Publishing Ltd.

Fluoroester Co-Solvents for Low-Temperature Li+ Cells

NASA Technical Reports Server (NTRS)

Smart, Marshall; Bugga, Ratnakumar; Prakash, G. K. Surya; Smith, Kiah; Bhalla, Pooja

2009-01-01

Electrolytes comprising LiPF6 dissolved in alkyl carbonate/fluoroester mixtures have been found to afford improved low-temperature performance and greater high-temperature resilience in rechargeable lithium-ion electrochemical cells. These and other electrolytes comprising lithium salts dissolved mixtures of esters have been studied in continuing research directed toward extending the lower limit of operating temperatures of such cells. This research at earlier stages, and the underlying physical and chemical principles, were reported in numerous previous NASA Tech Briefs articles. The purpose of the present focus on high-temperature resilience in addition to low-temperature performance is to address issues posed by the flammability of the esters and, at temperatures near the upper end (about 55 C) of their intended operating temperature range, by their high chemical reactivity. As used here, high-temperature resilience signifies, loosely, a desired combination of low flammability of an electrolyte mixture and the ability of a cell that contains the mixture to sustain a relatively small loss of reversible charge/discharge capacity during storage in the fully charged condition at high temperature. The selection of fluoroesters for study as candidate electrolyte solvent components to increase high-temperature resilience was prompted in part by the observation that like other halogenated compounds, fluoroesters have low flammability. The fluoroesters investigated in this study include trifluoroethyl butyrate (TFEB), ethyl trifluoroacetate (ETFA), trifluoroethyl acetate (TFEA), and methyl pentafluoropropionate (MPFP). Solvent mixtures were prepared by mixing these fluoroesters with two other esters: ethylene carbonate (EC) and ethyl methyl carbonate (EMC).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor-Pashow, K.; Fondeur, F.; White, T.

Savannah River National Laboratory (SRNL) was tasked with identifying and developing at least one, but preferably two methods for quantifying the suppressor in the Next Generation Solvent (NGS) system. The suppressor is a guanidine derivative, N,N',N"-tris(3,7-dimethyloctyl)guanidine (TiDG). A list of 10 possible methods was generated, and screening experiments were performed for 8 of the 10 methods. After completion of the screening experiments, the non-aqueous acid-base titration was determined to be the most promising, and was selected for further development as the primary method. {sup 1}H NMR also showed promising results from the screening experiments, and this method was selected formore » further development as the secondary method. Other methods, including {sup 36}Cl radiocounting and ion chromatography, also showed promise; however, due to the similarity to the primary method (titration) and the inability to differentiate between TiDG and TOA (tri-n-ocytlamine) in the blended solvent, {sup 1}H NMR was selected over these methods. Analysis of radioactive samples obtained from real waste ESS (extraction, scrub, strip) testing using the titration method showed good results. Based on these results, the titration method was selected as the method of choice for TiDG measurement. {sup 1}H NMR has been selected as the secondary (back-up) method, and additional work is planned to further develop this method and to verify the method using radioactive samples. Procedures for analyzing radioactive samples of both pure NGS and blended solvent were developed and issued for the both methods.« less

Cleaning painted surfaces: evaluation of leaching phenomenon induced by solvents applied for the removal of gel residues.

PubMed

Casoli, Antonella; Di Diego, Zaira; Isca, Clelia

2014-12-01

Cleaning is one of the most important, delicate, and at the same time controversial processes in the conservation treatment of paintings. Although a strict definition of cleaning would be the removal of dirt, grime, or other accretions (surface cleaning), in the conservation field, cleaning is used in the broader meaning to include thinning/removing altered or “unwanted layers” of materials without damaging or altering the physicochemical properties of the surfaces to be preserved. The cleaning of unvarnished paintings is one of the most critical issues that are currently discussed. Several studies exist regarding different cleaning tools, such as gels, soaps, enzymes, ionic liquids, and foams, as well as various dry methods and lasers, but only a few have been performed on the risk associated with the use of water and organic solvents for the cleaning treatments in relation to the original paint binder. The aim of the study is to verify analytically the behavior of water gelling agents during cleaning treatments and the interaction of the following elements: water or organic solvents applied for the removal of gel residues with the original lipid paint binder. For this purpose, the study was conducted on a fragment of canvas painting (sixteenth to seventeenth century) of Soprintendenza per i Beni Storici, Artistici ed Etnoantropologici del Friuli Venezia Giulia (Superintendence for the Historical, Artistic and Ethno-anthropological Heritage of Friuli Venezia Giulia), Udine by means of Fourier transform infrared spectroscopy, gas chromatography/mass spectrometry, and scanning electron microscopy.

Safer Electrolytes for Lithium-Ion Batteries: State of the Art and Perspectives.

PubMed

Kalhoff, Julian; Eshetu, Gebrekidan Gebresilassie; Bresser, Dominic; Passerini, Stefano

2015-07-08

Lithium-ion batteries are becoming increasingly important for electrifying the modern transportation system and, thus, hold the promise to enable sustainable mobility in the future. However, their large-scale application is hindered by severe safety concerns when the cells are exposed to mechanical, thermal, or electrical abuse conditions. These safety issues are intrinsically related to their superior energy density, combined with the (present) utilization of highly volatile and flammable organic-solvent-based electrolytes. Herein, state-of-the-art electrolyte systems and potential alternatives are briefly surveyed, with a particular focus on their (inherent) safety characteristics. The challenges, which so far prevent the widespread replacement of organic carbonate-based electrolytes with LiPF6 as the conducting salt, are also reviewed herein. Starting from rather "facile" electrolyte modifications by (partially) replacing the organic solvent or lithium salt and/or the addition of functional electrolyte additives, conceptually new electrolyte systems, including ionic liquids, solvent-free, and/or gelled polymer-based electrolytes, as well as solid-state electrolytes, are also considered. Indeed, the opportunities for designing new electrolytes appear to be almost infinite, which certainly complicates strict classification of such systems and a fundamental understanding of their properties. Nevertheless, these innumerable opportunities also provide a great chance of developing highly functionalized, new electrolyte systems, which may overcome the afore-mentioned safety concerns, while also offering enhanced mechanical, thermal, physicochemical, and electrochemical performance. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Parallelizing alternating direction implicit solver on GPUs

USDA-ARS?s Scientific Manuscript database

We present a parallel Alternating Direction Implicit (ADI) solver on GPUs. Our implementation significantly improves existing implementations in two aspects. First, we address the scalability issue of existing Parallel Cyclic Reduction (PCR) implementations by eliminating their hardware resource con...

Ethical Issues in Live-Donor Reimbursement Program.

PubMed

Voo, T C; Koh, S; Campbell, A V

2016-04-01

Reimbursement of expenses and costs incurred by live organ donation is permitted in many countries to encourage donation and to protect the welfare of live donors. Potential ethical issues may arise with reimbursement programs and their implementation, which vary across countries. This paper discusses some ethical issues with live donor reimbursement to stimulate discussion on how to ethically enhance its implementation to improve outcomes for both donors and recipients. In addition, we will consider whether reimbursement should be supplemented with compensation for nonfinancial losses, such as pain and suffering, to encourage live donation. Copyright © 2016 Elsevier Inc. All rights reserved.

PURPA 210 avoided cost rates: Economic and implementation issues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Devine, M.D.; Chartock, M.A.; Gunn, E.M.

The purpose of Section 210 of the Public Utilities Regulatory Policies Act (PURPA) was to promote the utilization of waste and renewable fuels and cogeneration processes for increasing electric power supplies. It represents a radical change in policy by allowing financially unregulated parties to generate power in ''qualifying facilities'' and by requiring utilities to purchase this power at the utilities' marginal (or ''avoided'') cost. PURPA 210 has clearly had a major impact as measured by the actual and proposed number of new qualifying facilities; however, implementation has been difficult due to the adversarial nature of the process for negotiating ormore » setting the avoided cost rates. This paper reviews the pertinent PURPA rules and regulations, analyzes the status of current avoided cost rates that have been established, and discusses implementation issues and options for resolving those issues.« less

Used Solvent Testing and Reclamation. Volume 2. Vapor Degreasing and Precision Cleaning Solvents

DTIC Science & Technology

1988-12-01

of 5 to 500 ppm in halogenated solvents using Karl - Fischer reagent. Arbitrary criteria to identify a spent solvent have evolved in various industries... methods of managing waste solvent. Some DOD installations are reclaiming used solvents rather than discarding them. Reclamation is feasible because the...most E E CT E reliable methods for testing solvent quality. Further testing isnecessary for chlorinated solvents to determine the inhibitor con- FEB 24

Issues in the digital implementation of control compensators. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Moroney, P.

1979-01-01

Techniques developed for the finite-precision implementation of digital filters were used, adapted, and extended for digital feedback compensators, with particular emphasis on steady state, linear-quadratic-Gaussian compensators. Topics covered include: (1) the linear-quadratic-Gaussian problem; (2) compensator structures; (3) architectural issues: serialism, parallelism, and pipelining; (4) finite wordlength effects: quantization noise, quantizing the coefficients, and limit cycles; and (5) the optimization of structures.

Process for removing halogenated aliphatic and aromatic compounds from petroleum products

DOEpatents

Googin, J.M.; Napier, J.M.; Travaglini, M.A.

1983-09-20

A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.

Process for removing halogenated aliphatic and aromatic compounds from petroleum products

DOEpatents

Googin, John M.; Napier, John M.; Travaglini, Michael A.

1983-01-01

A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced.

Process for removing halogenated aliphatic and aromatic compounds from petroleum products. [Polychlorinated biphenyls; methylene chloride; perchloroethylene; trichlorofluoroethane; trichloroethylene; chlorobenzene

DOEpatents

Googin, J.M.; Napier, J.M.; Travaglini, M.A.

1982-03-31

A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contracting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible polyhydroxy compound, such as, water, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds in the low polar or nonpolar solvent by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered for recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 2 tables.

Strategies to Build Readiness in Community Mobilization Efforts for Implementation in a Multi-Year Teen Pregnancy Prevention Initiative.

PubMed

Bhuiya, Nazmim; House, L Duane; Desmarais, Jeffrey; Fletcher, Erica; Conlin, Maeve; Perez-McAdoo, Sarah; Waggett, Jessica; Tendulkar, Shalini A

2017-03-01

This paper describes an assessment of community readiness to implement a community-wide teen pregnancy prevention initiative, Youth First, and presents strategies used to enhance this readiness as informed by the assessment. Twenty-five community stakeholder interviews were conducted to assess four domains of readiness: (1) attitudes, perception, and knowledge of teen pregnancy; (2) perceived level of readiness; (3) resources, existing and current efforts; and (4) leadership. Interview transcripts were coded and analyzed to identify key themes. Stakeholders acknowledged teen pregnancy as an issue but lacked contextual information. They also perceived the community as ready to address the issue and recognized some organizations already championing efforts. However, many key players were not involved, and ongoing data collection to assess teen pregnancy and prevention efforts was limited. Though many stakeholders were ready to engage in teen pregnancy prevention efforts, they required additional information and training to appropriately address the issue. In response to the assessment findings, several strategies were applied to address readiness and build Youth First partners' capacity to implement the community-wide initiative. Thus, to successfully implement community-wide prevention efforts, it is valuable to assess the level of community readiness to address health issues. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Continuous countercurrent membrane column for the separation of solute/solvent and solvent/solvent systems

DOEpatents

Nerad, Bruce A.; Krantz, William B.

1988-01-01

A reverse osmosis membrane process or hybrid membrane - complementary separator process for producing enriched product or waste streams from concentrated and dilute feed streams for both solvent/solvent and solute/solvent systems is described.

COMPUTER AIDED SOLVENT DESIGN FOR THE ENVIRONMENT

EPA Science Inventory

Solvent substitution is an effective and useful means of eliminating the use of harmful solvents, but finding substitute solvents which are less harmful and as effective as currently used solvents presents significant difficulties. Solvent substitution is a form of reverse engin...

IPAS Implementation Handbook

ERIC Educational Resources Information Center

Brooks, D. Christopher

2014-01-01

While the use of analytics to promote student success is gaining in popularity, basic questions about what IPAS is and the issues institutions face during implementation and integration. The "IPAS Implementation Handbook" catalogs the experiences, observations, and practical advice from 19 institutions engaged in IPAS implementation…

Hard-sphere fluid adsorbed in an annular wedge: The depletion force of hard-body colloidal physics

NASA Astrophysics Data System (ADS)

Herring, A. R.; Henderson, J. R.

2007-01-01

Many important issues of colloidal physics can be expressed in the context of inhomogeneous fluid phenomena. When two large colloids approach one another in solvent, they interact at least partly by the response of the solvent to finding itself adsorbed in the annular wedge formed between the two colloids. At shortest range, this fluid mediated interaction is known as the depletion force/interaction because solvent is squeezed out of the wedge when the colloids approach closer than the diameter of a solvent molecule. An equivalent situation arises when a single colloid approaches a substrate/wall. Accurate treatment of this interaction is essential for any theory developed to model the phase diagrams of homogeneous and inhomogeneous colloidal systems. The aim of our paper is a test of whether or not we possess sufficient knowledge of statistical mechanics that can be trusted when applied to systems of large size asymmetry and the depletion force in particular. When the colloid particles are much larger than a solvent diameter, the depletion force is dominated by the effective two-body interaction experienced by a pair of solvated colloids. This low concentration limit of the depletion force has therefore received considerable attention. One route, which can be rigorously based on statistical mechanical sum rules, leads to an analytic result for the depletion force when evaluated by a key theoretical tool of colloidal science known as the Derjaguin approximation. A rival approach has been based on the assumption that modern density functional theories (DFT) can be trusted for systems of large size asymmetry. Unfortunately, these two theoretical predictions differ qualitatively for hard sphere models, as soon as the solvent density is higher than about 2/3 that at freezing. Recent theoretical attempts to understand this dramatic disagreement have led to the proposal that the Derjaguin and DFT routes represent opposite limiting behavior, for very large size asymmetry and molecular sized mixtures, respectively. This proposal implies that nanocolloidal systems lie in between the two limits, so that the depletion force no longer scales linearly with the colloid radius. That is, by decreasing the size ratio from mesoscopic to molecular sized solutes, one moves smoothly between the Derjaguin and the DFT predictions for the depletion force scaled by the colloid radius. We describe the results of a simulation study designed specifically as a test of compatibility with this complex scenario. Grand canonical simulation procedures applied to hard-sphere fluid adsorbed in a series of annular wedges, representing the depletion regime of hard-body colloidal physics, confirm that neither the Derjaguin approximation, nor advanced formulations of DFT, apply at moderate to high solvent density when the geometry is appropriate to nanosized colloids. Our simulations also allow us to report structural characteristics of hard-body solvent adsorbed in hard annular wedges. Both these aspects are key ingredients in the proposal that unifies the disparate predictions, via the introduction of new physics. Our data are consistent with this proposed physics, although as yet limited to a single colloidal size asymmetry.

Study on thick film spin-on carbon hardmask

NASA Astrophysics Data System (ADS)

Kim, Taeho; Kim, Youngmin; Hwang, Sunmin; Lee, Hyunsoo; Han, Miyeon; Lim, Sanghak

2017-03-01

A thick spin-on carbon hardmask (SOH) material is designed to overcome inherent problems of amorphous deposited carbon layer (ACL) and thick photoresist. For ACL in use of semiconductor production process, especially when film thickness from sub-micrometer up to few micrometers is required, not only its inherent low transparency at long wavelength light often causes alignment problems with under layers, but also considerable variation of film thickness within a wafer can also cause patterning problems. To avoid these issues, a thick SOH is designed with monomers of high transparency and good solubility at the same time. In comparison with photoresist, the SOH has good etch resistance and high thermal stability, and it provides wide process window of decreased film thickness and increased thermal budget up to 400°C after processes such as high temperature deposition of SiON. In order to achieve high thickness along with uniform film, many solvent factors was considered such as solubility parameter, surface tension, vapor pressure, and others. By optimizing many solvent factors, we were able to develop a product with a good coating performance

Coupled-cluster based approach for core-level states in condensed phase: Theory and application to different protonated forms of aqueous glycine

DOE PAGES

Sadybekov, Arman; Krylov, Anna I.

2017-07-07

A theoretical approach for calculating core-level states in condensed phase is presented. The approach is based on equation-of-motion coupled-cluster theory (EOMCC) and effective fragment potential (EFP) method. By introducing an approximate treatment of double excitations in the EOM-CCSD (EOM-CC with single and double substitutions) ansatz, we address poor convergence issues that are encountered for the core-level states and significantly reduce computational costs. While the approximations introduce relatively large errors in the absolute values of transition energies, the errors are systematic. Consequently, chemical shifts, changes in ionization energies relative to reference systems, are reproduced reasonably well. By using different protonation formsmore » of solvated glycine as a benchmark system, we show that our protocol is capable of reproducing the experimental chemical shifts with a quantitative accuracy. The results demonstrate that chemical shifts are very sensitive to the solvent interactions and that explicit treatment of solvent, such as EFP, is essential for achieving quantitative accuracy.« less

Chain exchange in triblock copolymer micelles

NASA Astrophysics Data System (ADS)

Lu, Jie; Lodge, Timothy; Bates, Frank

2015-03-01

Block polymer micelles offer a host of technological applications including drug delivery, viscosity modification, toughening of plastics, and colloidal stabilization. Molecular exchange between micelles directly influences the stability, structure and access to an equilibrium state in such systems and this property recently has been shown to be extraordinarily sensitive to the core block molecular weight in diblock copolymers. The dependence of micelle chain exchange dynamics on molecular architecture has not been reported. The present work conclusively addresses this issue using time-resolved small-angle neutron scattering (TR-SANS) applied to complimentary S-EP-S and EP-S-EP triblock copolymers dissolved in squalane, a selective solvent for the EP blocks, where S and EP refer to poly(styrene) and poly(ethylenepropylene), respectively. Following the overall SANS intensity as a function of time from judiciously deuterium labelled polymer and solvent mixtures directly probes the rate of molecular exchange. Remarkably, the two triblocks display exchange rates that differ by approximately ten orders of magnitude, even though the solvophobic S blocks are of comparable size. This discovery is considered in the context of a model that successfully explains S-EP diblock exchange dynamics.

Ammonium Additives to Dissolve Lithium Sulfide through Hydrogen Binding for High-Energy Lithium-Sulfur Batteries.

PubMed

Pan, Huilin; Han, Kee Sung; Vijayakumar, M; Xiao, Jie; Cao, Ruiguo; Chen, Junzheng; Zhang, Jiguang; Mueller, Karl T; Shao, Yuyan; Liu, Jun

2017-02-08

In rechargeable Li-S batteries, the uncontrollable passivation of electrodes by highly insulating Li 2 S limits sulfur utilization, increases polarization, and decreases cycling stability. Dissolving Li 2 S in organic electrolyte is a facile solution to maintain the active reaction interface between electrolyte and sulfur cathode, and thus address the above issues. Herein, ammonium salts are demonstrated as effective additives to promote the dissolution of Li 2 S to 1.25 M in DMSO solvent at room temperature. NMR measurements show that the strong hydrogen binding effect of N-H groups plays a critical role in dissolving Li 2 S by forming complex ligands with S 2- anions coupled with the solvent's solvating surrounding. Ammonium additives in electrolyte can also significantly improve the oxidation kinetics of Li 2 S, and therefore enable the direct use of Li 2 S as cathode material in Li-S battery system in the future. This provides a new approach to manage the solubility of lithium sulfides through cation coordination with sulfide anion.

Molecular dynamics simulations of biological membranes and membrane proteins using enhanced conformational sampling algorithms.

PubMed

Mori, Takaharu; Miyashita, Naoyuki; Im, Wonpil; Feig, Michael; Sugita, Yuji

2016-07-01

This paper reviews various enhanced conformational sampling methods and explicit/implicit solvent/membrane models, as well as their recent applications to the exploration of the structure and dynamics of membranes and membrane proteins. Molecular dynamics simulations have become an essential tool to investigate biological problems, and their success relies on proper molecular models together with efficient conformational sampling methods. The implicit representation of solvent/membrane environments is reasonable approximation to the explicit all-atom models, considering the balance between computational cost and simulation accuracy. Implicit models can be easily combined with replica-exchange molecular dynamics methods to explore a wider conformational space of a protein. Other molecular models and enhanced conformational sampling methods are also briefly discussed. As application examples, we introduce recent simulation studies of glycophorin A, phospholamban, amyloid precursor protein, and mixed lipid bilayers and discuss the accuracy and efficiency of each simulation model and method. This article is part of a Special Issue entitled: Membrane Proteins edited by J.C. Gumbart and Sergei Noskov. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Carbon Dioxide Capture by Deep Eutectic Solvent Impregnated Sea Mango Activated Carbon

NASA Astrophysics Data System (ADS)

Zulkurnai, N. Z.; Ali, U. F. Md.; Ibrahim, N.; Manan, N. S. Abdul

2018-03-01

The increment amount of the CO2 emission by years has become a major concern worldwide due to the global warming issue. However, the influence modification of activated carbon (AC) has given a huge revolution in CO2 adsorption capture compare to the unmodified AC. In the present study, the Deep Eutectic Solvent (DES) modified surface AC was used for Carbon Dioxide (CO2) capture in the fixed-bed column. The AC underwent pre-carbonization and carbonization processes at 519.8 °C, respectively, with flowing of CO2 gas and then followed by impregnation with 53.75% phosphoric acid (H3PO4) at 1:2 precursor-to-activant ratios. The prepared AC known as sea mango activated carbon (SMAC) was impregnated with DES at 1:2 solid-to-liquid ratio. The DES is composing of choline chloride and urea with ratio 1:2 choline chloride to urea. The optimum adsorption capacity of SMAC was 33.46 mgco2/gsol and 39.40 mgco2/gsol for DES modified AC (DESAC).

Mass spectrometry-based carboxyl footprinting of proteins: Method evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hao; Wen, Jianzhong; Huang, Richard Y-C.

2012-02-01

Protein structure determines function in biology, and a variety of approaches have been employed to obtain structural information about proteins. Mass spectrometry-based protein footprinting is one fast-growing approach. One labeling-based footprinting approach is the use of a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and glycine ethyl ester (GEE) to modify solvent-accessible carboxyl groups on glutamate (E) and aspartate (D). This paper describes method development of carboxyl-group modification in protein footprinting. The modification protocol was evaluated by using the protein calmodulin as a model. Because carboxyl-group modification is a slow reaction relative to protein folding and unfolding, there is an issue that modificationsmore » at certain sites may induce protein unfolding and lead to additional modification at sites that are not solvent-accessible in the wild-type protein. We investigated this possibility by using hydrogen deuterium amide exchange (H/DX). The study demonstrated that application of carboxyl group modification in probing conformational changes in calmodulin induced by Ca{sup 2+} binding provides useful information that is not compromised by modification-induced protein unfolding.« less

Electronic Structure at Electrode/Electrolyte Interfaces in Magnesium based Batteries

NASA Astrophysics Data System (ADS)

Balachandran, Janakiraman; Siegel, Donald

2015-03-01

Magnesium is a promising multivalent element for use in next generation electrochemical energy storage systems. However, a wide range of challenges such as low coulombic efficiency, low/varying capacity and cyclability need to be resolved in order to realize Mg based batteries. Many of these issues can be related to interfacial phenomena between the Mg anode and common electrolytes. Ab-initio based computational models of these interfaces can provide insights on the interfacial interactions that can be difficult to probe experimentally. In this work we present ab-initio computations of common electrolyte solvents (THF, DME) in contact with two model electrode surfaces namely -- (i) an ``SEI-free'' electrode based on Mg metal and, (ii) a ``passivated'' electrode consisting of MgO. We perform GW calculations to predict the reorganization of the molecular orbitals (HOMO/LUMO) upon contact with the these surfaces and their alignment with respect to the Fermi energy of the electrodes. These computations are in turn compared with more efficient GGA (PBE) & Hybrid (HSE) functional calculations. The results obtained from these computations enable us to qualitatively describe the stability of these solvent molecules at electrode-electrolyte interfaces

Coupled-cluster based approach for core-level states in condensed phase: Theory and application to different protonated forms of aqueous glycine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadybekov, Arman; Krylov, Anna I.

A theoretical approach for calculating core-level states in condensed phase is presented. The approach is based on equation-of-motion coupled-cluster theory (EOMCC) and effective fragment potential (EFP) method. By introducing an approximate treatment of double excitations in the EOM-CCSD (EOM-CC with single and double substitutions) ansatz, we address poor convergence issues that are encountered for the core-level states and significantly reduce computational costs. While the approximations introduce relatively large errors in the absolute values of transition energies, the errors are systematic. Consequently, chemical shifts, changes in ionization energies relative to reference systems, are reproduced reasonably well. By using different protonation formsmore » of solvated glycine as a benchmark system, we show that our protocol is capable of reproducing the experimental chemical shifts with a quantitative accuracy. The results demonstrate that chemical shifts are very sensitive to the solvent interactions and that explicit treatment of solvent, such as EFP, is essential for achieving quantitative accuracy.« less

Dry coating of solid dosage forms: an overview of processes and applications.

PubMed

Foppoli, Anastasia Anna; Maroni, Alessandra; Cerea, Matteo; Zema, Lucia; Gazzaniga, Andrea

2017-12-01

Dry coating techniques enable manufacturing of coated solid dosage forms with no, or very limited, use of solvents. As a result, major drawbacks associated with both organic solvents and aqueous coating systems can be overcome, such as toxicological, environmental, and safety-related issues on the one hand as well as costly drying phases and impaired product stability on the other. The considerable advantages related to solventless coating has been prompting a strong research interest in this field of pharmaceutics. In the article, processes and applications relevant to techniques intended for dry coating are analyzed and reviewed. Based on the physical state of the coat-forming agents, liquid- and solid-based techniques are distinguished. The former include hot-melt coating and coating by photocuring, while the latter encompass press coating and powder coating. Moreover, solventless techniques, such as injection molding and three-dimensional printing by fused deposition modeling, which are not purposely conceived for coating, are also discussed in that they would open new perspectives in the manufacturing of coated-like dosage forms.

Room-temperature ionic liquids and composite materials: platform technologies for CO(2) capture.

PubMed

Bara, Jason E; Camper, Dean E; Gin, Douglas L; Noble, Richard D

2010-01-19

Clean energy production has become one of the most prominent global issues of the early 21st century, prompting social, economic, and scientific debates regarding energy usage, energy sources, and sustainable energy strategies. The reduction of greenhouse gas emissions, specifically carbon dioxide (CO(2)), figures prominently in the discussions on the future of global energy policy. Billions of tons of annual CO(2) emissions are the direct result of fossil fuel combustion to generate electricity. Producing clean energy from abundant sources such as coal will require a massive infrastructure and highly efficient capture technologies to curb CO(2) emissions. Current technologies for CO(2) removal from other gases, such as those used in natural gas sweetening, are also capable of capturing CO(2) from power plant emissions. Aqueous amine processes are found in the vast majority of natural gas sweetening operations in the United States. However, conventional aqueous amine processes are highly energy intensive; their implementation for postcombustion CO(2) capture from power plant emissions would drastically cut plant output and efficiency. Membranes, another technology used in natural gas sweetening, have been proposed as an alternative mechanism for CO(2) capture from flue gas. Although membranes offer a potentially less energy-intensive approach, their development and industrial implementation lags far behind that of amine processes. Thus, to minimize the impact of postcombustion CO(2) capture on the economics of energy production, advances are needed in both of these areas. In this Account, we review our recent research devoted to absorptive processes and membranes. Specifically, we have explored the use of room-temperature ionic liquids (RTILs) in absorptive and membrane technologies for CO(2) capture. RTILs present a highly versatile and tunable platform for the development of new processes and materials aimed at the capture of CO(2) from power plant flue gas and in natural gas sweetening. The desirable properties of RTIL solvents, such as negligible vapor pressures, thermal stability, and a large liquid range, make them interesting candidates as new materials in well-known CO(2) capture processes. Here, we focus on the use of RTILs (1) as absorbents, including in combination with amines, and (2) in the design of polymer membranes. RTIL amine solvents have many potential advantages over aqueous amines, and the versatile chemistry of imidazolium-based RTILs also allows for the generation of new types of CO(2)-selective polymer membranes. RTIL and RTIL-based composites can compete with, or improve upon, current technologies. Moreover, owing to our experience in this area, we are developing new imidazolium-based polymer architectures and thermotropic and lyotropic liquid crystals as highly tailorable materials based on and capable of interacting with RTILs.

Programme Implementation in Social and Emotional Learning: Basic Issues and Research Findings

ERIC Educational Resources Information Center

Durlak, Joseph A.

2016-01-01

This paper discusses the fundamental importance of achieving quality implementation when assessing the impact of social and emotional learning interventions. Recent findings in implementation science are reviewed that include a definition of implementation, its relation to programme outcomes, current research on the factors that affect…

Processing liquid organic wastes at the NNL Preston laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coppersthwaite, Duncan; Greenwood, Howard; Docrat, Tahera

2013-07-01

Organic compounds of various kinds have been used in the nuclear industry for numerous duties in uranium chemical, metal and ceramic processing plants. In the course of the various operations undertaken, these organic compounds have become contaminated with uranic material, either accidentally or as an inevitable part of the process. Typically, the chemical/physical form and/or concentration of the uranic content of the organics has prevented disposal. In order to address the issue of contaminated liquid organic wastes, the National Nuclear Laboratory (NNL) has developed a suite of treatments designed to recover uranium and to render the waste suitable for disposal.more » The developed processes are operated at industrial scale via the NNL Preston Laboratory Residue Processing Plant. The Oil Waste Leaching (OWL) Process is a fully industrialised process used for the treatment of contaminated oils with approximately 200 tonnes of uranium contaminated oil being treated to date. The process was originally developed for the treatment of contaminated tributyl phosphate and odourless kerosene which had been adsorbed onto sawdust. However, over the years, the OWL process has been refined for a range of oils including 'water emulsifiable' cutting oils, lubricating oils, hydraulic oils/fluids and 'Fomblin' (fully fluorinated) oils. Chemically, the OWL process has proved capable of treating solvents as well as oils but the highly volatile/flammable nature of many solvents has required additional precautions compared with those required for oil treatment. These additional precautions led to the development of the Solvent Treatment Advanced Rig (STAR), an installation operated under an inert atmosphere. STAR is a small 'module' (100 dm{sup 3} volume) which allows the treatment of both water miscible and immiscible solvents. This paper discusses the challenges associated with the treatment of liquid organic wastes and the process developments which have allowed a wide range of materials to be successfully treated. (authors)« less

Electrostatics of proteins in dielectric solvent continua. I. Newton's third law marries qE forces

NASA Astrophysics Data System (ADS)

Stork, Martina; Tavan, Paul

2007-04-01

The authors reformulate and revise an electrostatic theory treating proteins surrounded by dielectric solvent continua [B. Egwolf and P. Tavan, J. Chem. Phys. 118, 2039 (2003)] to make the resulting reaction field (RF) forces compatible with Newton's third law. Such a compatibility is required for their use in molecular dynamics (MD) simulations, in which the proteins are modeled by all-atom molecular mechanics force fields. According to the original theory the RF forces, which are due to the electric field generated by the solvent polarization and act on the partial charges of a protein, i.e., the so-called qE forces, can be quite accurately computed from Gaussian RF dipoles localized at the protein atoms. Using a slightly different approximation scheme also the RF energies of given protein configurations are obtained. However, because the qE forces do not account for the dielectric boundary pressure exerted by the solvent continuum on the protein, they do not obey the principle that actio equals reactio as required by Newton's third law. Therefore, their use in MD simulations is severely hampered. An analysis of the original theory has led the authors now to a reformulation removing the main difficulties. By considering the RF energy, which represents the dominant electrostatic contribution to the free energy of solvation for a given protein configuration, they show that its negative configurational gradient yields mean RF forces obeying the reactio principle. Because the evaluation of these mean forces is computationally much more demanding than that of the qE forces, they derive a suggestion how the qE forces can be modified to obey Newton's third law. Various properties of the thus established theory, particularly issues of accuracy and of computational efficiency, are discussed. A sample application to a MD simulation of a peptide in solution is described in the following paper [M. Stork and P. Tavan, J. Chem. Phys., 126, 165106 (2007).

Practical Issues in Developing a Culturally Tailored Physical Activity Promotion Program for Chinese and Korean American Midlife Women: A Pilot Study.

PubMed

Chee, Wonshik; Kim, Sangmi; Chu, Tsung-Lan; Tsai, Hsiu-Min; Ji, Xiaopeng; Zhang, Jingwen; Chee, Eunice; Im, Eun-Ok

2016-11-21

With advances in computer technologies, Web-based interventions are widely accepted and welcomed by health care providers and researchers. Although the benefits of Web-based interventions on physical activity promotion have been documented, the programs have rarely targeted Asian Americans, including Asian American midlife women. Subsequently, culturally competent Web-based physical activity programs for Asian Americans may be necessary. The purpose of our study was to explore practical issues in developing and implementing a culturally competent Web-based physical activity promotion program for 2 groups of Asian American women-Chinese American and Korean American midlife women-and to provide implications for future research. While conducting the study, the research team members wrote individual memos on issues and their inferences on plausible reasons for the issues. The team had group discussions each week and kept the minutes of the discussions. Then, the memos and minutes were analyzed using a content analysis method. We identified practical issues in 4 major idea categories: (1) bilingual translators' language orientations, (2) cultural sensitivity requirement, (3) low response rate, interest, and retention, and (4) issues in implementation logistics. Based on the issues, we make several suggestions for the use of bilingual translators, motivational strategies, and implementation logistics. ©Wonshik Chee, Sangmi Kim, Tsung-Lan Chu, Hsiu-Min Tsai, Xiaopeng Ji, Jingwen Zhang, Eunice Chee, Eun-Ok Im. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 21.11.2016.

Ethical issues with colorectal cancer screening-a systematic review.

PubMed

Hofmann, Bjørn

2017-06-01

Colorectal cancer (CRC) screening is widely recommended and implemented. However, sometimes CRC screening is not implemented despite good evidence, and some types of CRC screening are implemented despite lack of evidence. The objective of this article is to expose and elucidate relevant ethical issues in the literature on CRC screening that are important for open and transparent deliberation on CRC screening. An axiological question-based method is used for exposing and elucidating ethical issues relevant in HTA. A literature search in MEDLINE, Embase, PsycINFO, PubMed Bioethics subset, ISI Web of Knowledge, Bioethics Literature Database (BELIT), Ethics in Medicine (ETHMED), SIBIL Base dati di bioetica, LEWI Bibliographic Database on Ethics in the Sciences and Humanities, and EUROETHICS identified 870 references of which 114 were found relevant according to title and abstract. The content of the included papers were subject to ethical analysis to highlight the ethical issues, concerns, and arguments. A wide range of important ethical issues were identified. The main benefits are reduced relative CRC mortality rate, and potentially incidence rate, but there is no evidence of reduced absolute mortality rate. Potential harms are bleeding, perforation, false test results, overdetection, overdiagnosis, overtreatment (including unnecessary removal of polyps), and (rarely) death. Other important issues are related to autonomy and informed choice equity, justice, medicalization, and expanding disease. A series of important ethical issues have been identified and need to be addressed in open and transparent deliberation on CRC screening. © 2016 John Wiley & Sons, Ltd.

Experiences of Agency for Healthcare Research and Quality-funded projects that implemented practices for safer patient care.

PubMed

Taylor, Stephanie L; Ridgely, M Susan; Greenberg, Michael D; Sorbero, Melony E S; Teleki, Stephanie S; Damberg, Cheryl L; Farley, Donna O

2009-04-01

To synthesize lessons learned from the experiences of Agency for Healthcare Research and Quality-funded patient safety projects in implementing safe practices. Self-reported data from individual and group interviews with Original, Challenge, and Partnerships in Implementing Patient Safety (PIPS) grantees, from 2003 to 2006. Interviews with three grantee groups (n=60 total) implementing safe practice projects, with comparisons on factors influencing project implementation and sustainability. Semi-structured protocols contained open-ended questions on lessons learned and more structured questions on factors associated with project implementation and sustainability. The grantees shared common experiences, frequently identifying lessons learned regarding structural components needing to be in place before implementation, components of the implementation process, components of interventions' results needed for sustainability, changes in timelines or activities, unanticipated issues, and staff acceptance/adoption. Also, fewer Original grants had many of the factors related project to implementation/sustainability than the PIPS or Challenge grantees had. Although much of what was reported seemed like common sense, surprisingly few projects actually planned for or expected many of the barriers or facilitators they experienced during their project implementation. Others implementing practice improvements likely will share the experiences and issues identified by these implementation projects and can learn from their lessons.

7 CFR 7.36 - Implementation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... part, the Deputy Administrator, State and County Operations, or the Deputy Administrator, Management, ASCS, is authorized to issue the instructions and procedures referred to herein which implement the...

Diffusion of Small Solute Particles in Viscous Liquids: Cage Diffusion, a Result of Decoupling of Solute-Solvent Dynamics, Leads to Amplification of Solute Diffusion.

PubMed

Acharya, Sayantan; Nandi, Manoj K; Mandal, Arkajit; Sarkar, Sucharita; Bhattacharyya, Sarika Maitra

2015-08-27

We study the diffusion of small solute particles through solvent by keeping the solute-solvent interaction repulsive and varying the solvent properties. The study involves computer simulations, development of a new model to describe diffusion of small solutes in a solvent, and also mode coupling theory (MCT) calculations. In a viscous solvent, a small solute diffuses via coupling to the solvent hydrodynamic modes and also through the transient cages formed by the solvent. The model developed can estimate the independent contributions from these two different channels of diffusion. Although the solute diffusion in all the systems shows an amplification, the degree of it increases with solvent viscosity. The model correctly predicts that when the solvent viscosity is high, the solute primarily diffuses by exploiting the solvent cages. In such a scenario the MCT diffusion performed for a static solvent provides a correct estimation of the cage diffusion.

Apparatus and method for removing solvent from carbon dioxide in resin recycling system

DOEpatents

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

2009-01-06

A two-step resin recycling system and method solvent that produces essentially contaminant-free synthetic resin material. The system and method includes one or more solvent wash vessels to expose resin particles to a solvent, the solvent contacting the resin particles in the one or more solvent wash vessels to substantially remove contaminants on the resin particles. A separator is provided to separate the solvent from the resin particles after removal from the one or more solvent wash vessels. The resin particles are next exposed to carbon dioxide in a closed loop carbon dioxide system. The closed loop system includes a carbon dioxide vessel where the carbon dioxide is exposed to the resin, substantially removing any residual solvent remaining on the resin particles after separation. A separation vessel is also provided to separate the solvent from the solvent laden carbon dioxide. Both the carbon dioxide and the solvent are reused after separation in the separation vessel.

Issues and Answers about Section 504.

ERIC Educational Resources Information Center

American School and University, 1979

1979-01-01

The first of several installments that address the complex issues and questions related to implementation of the requirement that persons should have equal educational opportunity despite handicap. (Author)

Brownian cluster dynamics with short range patchy interactions: Its application to polymers and step-growth polymerization

NASA Astrophysics Data System (ADS)

Prabhu, A.; Babu, S. B.; Dolado, J. S.; Gimel, J.-C.

2014-07-01

We present a novel simulation technique derived from Brownian cluster dynamics used so far to study the isotropic colloidal aggregation. It now implements the classical Kern-Frenkel potential to describe patchy interactions between particles. This technique gives access to static properties, dynamics and kinetics of the system, even far from the equilibrium. Particle thermal motions are modeled using billions of independent small random translations and rotations, constrained by the excluded volume and the connectivity. This algorithm, applied to a single polymer chain leads to correct static and dynamic properties, in the framework where hydrodynamic interactions are ignored. By varying patch angles, various local chain flexibilities can be obtained. We have used this new algorithm to model step-growth polymerization under various solvent qualities. The polymerization reaction is modeled by an irreversible aggregation between patches while an isotropic finite square-well potential is superimposed to mimic the solvent quality. In bad solvent conditions, a competition between a phase separation (due to the isotropic interaction) and polymerization (due to patches) occurs. Surprisingly, an arrested network with a very peculiar structure appears. It is made of strands and nodes. Strands gather few stretched chains that dip into entangled globular nodes. These nodes act as reticulation points between the strands. The system is kinetically driven and we observe a trapped arrested structure. That demonstrates one of the strengths of this new simulation technique. It can give valuable insights about mechanisms that could be involved in the formation of stranded gels.

Initiation of universal tumor screening for Lynch syndrome in colorectal cancer patients as a model for the implementation of genetic information into clinical oncology practice.

PubMed

Cohen, Stacey A; Laurino, Mercy; Bowen, Deborah J; Upton, Melissa P; Pritchard, Colin; Hisama, Fuki; Jarvik, Gail; Fichera, Alessandro; Sjoding, Britta; Bennett, Robin L; Naylor, Lorraine; Jacobson, Angela; Burke, Wylie; Grady, William M

2016-02-01

Lynch syndrome confers a hereditary predisposition to colorectal and other cancers. Universal tumor screening (UTS) for Lynch syndrome is recommended by several professional societies, but the implementation can be complex. This article describes the evaluation, process development, and initiation of Lynch syndrome UTS at a tertiary referral cancer center. A multidisciplinary team developed the new process design. Issues in 5 themes were noted: timing, funding, second-opinion patients, result processing, and the role of genetics providers. A committee approach was used to examine each issue for process-improvement development. The issues related to testing were addressed individually for the successful implementation of UTS at the institutional level. In the conventional-care period, 9 of 30 cases (30%) received Lynch syndrome screening, and 4 cases were referred to medical genetics. During the 6 months following the implementation of UTS, 32 of 44 patients (73%) received Lynch syndrome screening. The 13 unscreened patients all had identified reasons for nonscreening (eg, financial limitations). Ten patients were referred to medical genetics, which identified no new cases of Lynch syndrome, but a low-risk adenomatous polyposis coli (APC) variant was detected in 1 individual. The implementation of effective Lynch syndrome UTS can feasibly alter practice at the institutional level. This experience with the assessment and management of issues relevant to the successful implementation of a new clinical care paradigm based on emerging technology has implications for the uptake of advances across molecular oncology into clinical practice, and this is highly relevant in the current era of rapidly evolving genomic technology. © 2015 American Cancer Society.

Organizational issues in the implementation and adoption of health information technology innovations: an interpretative review.

PubMed

Cresswell, Kathrin; Sheikh, Aziz

2013-05-01

Implementations of health information technologies are notoriously difficult, which is due to a range of inter-related technical, social and organizational factors that need to be considered. In the light of an apparent lack of empirically based integrated accounts surrounding these issues, this interpretative review aims to provide an overview and extract potentially generalizable findings across settings. We conducted a systematic search and critique of the empirical literature published between 1997 and 2010. In doing so, we searched a range of medical databases to identify review papers that related to the implementation and adoption of eHealth applications in organizational settings. We qualitatively synthesized this literature extracting data relating to technologies, contexts, stakeholders, and their inter-relationships. From a total body of 121 systematic reviews, we identified 13 systematic reviews encompassing organizational issues surrounding health information technology implementations. By and large, the evidence indicates that there are a range of technical, social and organizational considerations that need to be deliberated when attempting to ensure that technological innovations are useful for both individuals and organizational processes. However, these dimensions are inter-related, requiring a careful balancing act of strategic implementation decisions in order to ensure that unintended consequences resulting from technology introduction do not pose a threat to patients. Organizational issues surrounding technology implementations in healthcare settings are crucially important, but have as yet not received adequate research attention. This may in part be due to the subjective nature of factors, but also due to a lack of coordinated efforts toward more theoretically-informed work. Our findings may be used as the basis for the development of best practice guidelines in this area. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Solvent-Polarity-Induced Active Layer Morphology Control in Crystalline Diketopyrrolopyrrole-Based Low Band Gap Polymer Photovoltaics

NASA Astrophysics Data System (ADS)

Ferdous, Sunzida; Liu, Feng; Wang, Dong; Russell, Thomas

2014-03-01

The effects of various processing solvents on the morphology of diketopyrrolopyrrole (DPP)-based low band gap polymer (PDPPBT) and phenyl-C71-butyric acid methyl ester (PC71BM) blends are studied. The quality of the processing solvents was varied systematically using a mixture of a non-aromatic polar primary solvent with high boiling point secondary solvents of increasing polarities. An unfavorable solvent-PC71BM interaction affects the growth process of polymer crystallites inside the blend. When non-aromatic polar solvent was used, large PC71BM aggregates were formed that increase in size with the addition of non-polar secondary solvents. When polar solvents were instead used as the secondary solvents, the size scales of the aggregates decrease markedly, creating a percolated fibrillar network. Power conversion efficiencies of 0.03% to 5% are obtained, depending on the solvent system used.

Development of deep eutectic solvents applied in extraction and separation.

PubMed

Li, Xiaoxia; Row, Kyung Ho

2016-09-01

Deep eutectic solvents, as an alternative to ionic liquids, have greener credentials than ionic liquids, and have attracted considerable attention in related chemical research. Deep eutectic solvents have attracted increasing attention in chemistry for the extraction and separation of various target compounds from natural products. This review highlights the preparation of deep eutectic solvents, unique properties of deep eutectic solvents, and synthesis of deep-eutectic-solvent-based materials. On the other hand, application in the extraction and separation of deep eutectic solvents is also included in this report. In this paper, the available data and references in this field are reviewed to summarize the applications and developments of deep eutectic solvents. Based on the development of deep eutectic solvents, an exploitation of new deep eutectic solvents and deep eutectic solvents-based materials is expected to diversify into extraction and separation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PARIS II: Computer Aided Solvent Design for Pollution Prevention

EPA Science Inventory

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...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mezyk, Stephen P.; Mincher, Bruce J.; Nilsson, Mikael

This document is the final report for the Nuclear Energy Universities Program (NEUP) grant 10-910 (DE-AC07-05ID14517) “Alpha Radiolysis of Nuclear Solvent Extraction Ligands used for An(III) and Ln(III) Separations”. The goal of this work was to obtain a quantitative understanding of the impacts of both low Linear Energy Transfer (LET, gamma-rays) and high LET (alpha particles) radiation chemistry occurring in future large-scale separations processes. This quantitative understanding of the major radiation effects on diluents and ligands is essential for optimal process implementation, and could result in significant cost savings in the future.

75 FR 74045 - Guidance on Planning, Implementing, Maintaining, and Enforcing Institutional Controls at...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-30

..., Implementing, Maintaining, and Enforcing Institutional Controls at Contaminated Sites AGENCY: Environmental... stakeholder input regarding the issues addressed in the EPA interim final guidance, titled Institutional Controls: A Guide to Planning, Implementing, Maintaining, and Enforcing Institutional Controls at...

Organic solvent desorption from two tegafur polymorphs.

PubMed

Bobrovs, Raitis; Actiņš, Andris

2013-11-30

Desorption behavior of 8 different solvents from α and β tegafur (5-fluoro-1-(tetrahydro-2-furyl)uracil) has been studied in this work. Solvent desorption from samples stored at 95% and 50% relative solvent vapor pressure was studied in isothermal conditions at 30 °C. The results of this study demonstrated that: solvent desorption rate did not differ significantly for both phases; solvent desorption in all cases occurred faster from samples with the largest particle size; and solvent desorption in most cases occurred in two steps. Structure differences and their surface properties were not of great importance on the solvent desorption rates because the main factor affecting desorption rate was sample particle size and sample morphology. Inspection of the structure packing showed that solvent desorption rate and amount of solvent adsorbed were mainly affected by surface molecule arrangement and ability to form short contacts between solvent molecule electron donor groups and freely accessible tegafur tetrahydrofuran group hydrogens, as well as between solvents molecule proton donor groups and fluorouracil ring carbonyl and fluoro groups. Solvent desorption rates of acetone, acetonitrile, ethyl acetate and tetrahydrofuran multilayers from α and β tegafur were approximately 30 times higher than those of solvent monolayers. Scanning electron micrographs showed that sample storage in solvent vapor atmosphere promotes small tegafur particles recrystallization to larger particles. Copyright © 2013 Elsevier B.V. All rights reserved.

Strategic environmental noise mapping: methodological issues concerning the implementation of the EU Environmental Noise Directive and their policy implications.

PubMed

Murphy, E; King, E A

2010-04-01

This paper explores methodological issues and policy implications concerning the implementation of the EU Environmental Noise Directive (END) across Member States. Methodologically, the paper focuses on two key thematic issues relevant to the Directive: (1) calculation methods and (2) mapping methods. For (1), the paper focuses, in particular, on how differing calculation methods influence noise prediction results as well as the value of the EU noise indicator L(den) and its associated implications for comparability of noise data across EU states. With regard to (2), emphasis is placed on identifying the issues affecting strategic noise mapping, estimating population exposure, noise action planning and dissemination of noise mapping results to the general public. The implication of these issues for future environmental noise policy is also examined. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Experimentation and evaluation of advanced integrated system concepts

NASA Astrophysics Data System (ADS)

Ross, M.; Garrigus, K.; Gottschalck, J.; Rinearson, L.; Longee, E.

1980-09-01

This final report examines the implementation of a time-phased test bed for experimentation and evaluation of advanced system concepts relative to the future Defense Switched Network (DSN). After identifying issues pertinent to the DSN, a set of experiments which address these issues are developed. Experiments are ordered based on their immediacy and relative importance to DSN development. The set of experiments thus defined allows requirements for a time phased implementation of a test bed to be identified, and several generic test bed architectures which meet these requirements are examined. Specific architecture implementations are costed and cost/schedule profiles are generated as a function of experimental capability. The final recommended system consists of two separate test beds: a circuit switch test bed, configured around an off-the-shelf commercial switch, and directed toward the examination of nearer term and transitional issues raised by the evolving DSN; and a packet/hybrid test bed, featuring a discrete buildup of new hardware and software modules, and directed toward examination of the more advanced integrated voice and data telecommunications issues and concepts.

Ada 9X Project Report: Ada 9X Revision Issues. Release 1

DTIC Science & Technology

1990-04-01

interrupts in Ada. Users are using specialized run-time executives which promote semaphores , monitors , etc ., as well as interrupt support, are using...The focus here is on two specific problems: 1. lack of time-out on operations . 2. no efficient way to program a shared-variable monitor for the... operation . 43 !Issue implementation [3 - Remote Operations for Real-Time Systems ] The real-time implementation standards should define various remote

Employee Involvement. Issues for Agencies To Consider in Designing and Implementing Programs. Report to the Ranking Minority Member, Subcommittee on Federal Services, Post Office, and Civil Service, Committee on Governmental Affairs, U.S. Senate.

ERIC Educational Resources Information Center

General Accounting Office, Washington, DC. General Government Div.

An investigation identified issues that are important for federal agencies to consider in designing and implementing employee involvement programs. Employee involvement programs in the private sector and in the federal government were studied. The use of seven involvement practices was examined: suggestion systems, survey feedback, quality…

Feasibility study of shared-ride auto transit. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocur, G.; Zaelke, D.; Neumann, L.

1977-09-01

The report examines the feasibility of the implementation of shared-ride auto transit (SRAT), which is an innovative approach for increasing auto occupancy in rural and urban areas. The report focuses on operational concepts, potential usage, legal and regulatory issues, and institutional issues. Formulation of the SRAT concept was motivated by several concerns, such as: (1) energy conservation; (2) transit service to areas unable to economically justify conventional transit services, and to travel disadvantaged groups; (3) transit service replacement to achieve greater efficiency and to reduce transit deficits; (4) provision of inexpensive transit service; and (5) the increase of safety andmore » reliability of hitchhiking. Four case study sites (Boulder, Colorado; Boston, Massachusetts; Portland, Oregon; and Tidewater, Virginia), were used to identify the specific institutional issues likely to impact SRAT implementation for that site, and to identify the opportunities for designing, implementing and operating SRAT in a variety of institutional settings.« less

Pharmaceutical information systems and possible implementations of informed consent -- developing an heuristic.

PubMed

Ploug, Thomas; Holm, Søren

2012-11-16

Denmark has implemented a comprehensive, nationwide pharmaceutical information system, and this system has been evaluated by the Danish Council of Ethics. The system can be seen as an exemplar of a comprehensive health information system for clinical use. The paper analyses 1) how informed consent can be implemented in the system and how different implementations create different impacts on autonomy and control of information, and 2) arguments directed towards justifying not seeking informed consent in this context. Based on the analysis a heuristic is provided which enables a ranking and estimation of the impact on autonomy and control of information of different options for consent to entry of data into the system and use of data from the system.The danger of routinisation of consent is identified.The Danish pharmaceutical information system raises issues in relation to autonomy and control of information, issues that will also occur in relation to other similar comprehensive health information systems. Some of these issues are well understood and their impact can be judged using the heuristic which is provided. More research is, however needed in relation to routinisation of consent.

Order of wetting transitions in electrolyte solutions.

PubMed

Ibagon, Ingrid; Bier, Markus; Dietrich, S

2014-05-07

For wetting films in dilute electrolyte solutions close to charged walls we present analytic expressions for their effective interface potentials. The analysis of these expressions renders the conditions under which corresponding wetting transitions can be first- or second-order. Within mean field theory we consider two models, one with short- and one with long-ranged solvent-solvent and solvent-wall interactions. The analytic results reveal in a transparent way that wetting transitions in electrolyte solutions, which occur far away from their critical point (i.e., the bulk correlation length is less than half of the Debye length) are always first-order if the solvent-solvent and solvent-wall interactions are short-ranged. In contrast, wetting transitions close to the bulk critical point of the solvent (i.e., the bulk correlation length is larger than the Debye length) exhibit the same wetting behavior as the pure, i.e., salt-free, solvent. If the salt-free solvent is governed by long-ranged solvent-solvent as well as long-ranged solvent-wall interactions and exhibits critical wetting, adding salt can cause the occurrence of an ion-induced first-order thin-thick transition which precedes the subsequent continuous wetting as for the salt-free solvent.

7 CFR 622.5 - Guidelines.

Code of Federal Regulations, 2010 CFR

2010-01-01

... NEPA (40 CFR parts 1500-1508) issued by the Council on Environmental Quality, and in Economic and Environmental Principles and Guidelines for Water and Related Land Resources Implementation Studies issued by...

Information Issues and Contexts that Impair Team Based Communication Workflow: A Palliative Sedation Case Study.

PubMed

Cornett, Alex; Kuziemsky, Craig

2015-01-01

Implementing team based workflows can be complex because of the scope of providers involved and the extent of information exchange and communication that needs to occur. While a workflow may represent the ideal structure of communication that needs to occur, information issues and contextual factors may impact how the workflow is implemented in practice. Understanding these issues will help us better design systems to support team based workflows. In this paper we use a case study of palliative sedation therapy (PST) to model a PST workflow and then use it to identify purposes of communication, information issues and contextual factors that impact them. We then suggest how our findings could inform health information technology (HIT) design to support team based communication workflows.

Numerical integration techniques for curved-element discretizations of molecule-solvent interfaces.

PubMed

Bardhan, Jaydeep P; Altman, Michael D; Willis, David J; Lippow, Shaun M; Tidor, Bruce; White, Jacob K

2007-07-07

Surface formulations of biophysical modeling problems offer attractive theoretical and computational properties. Numerical simulations based on these formulations usually begin with discretization of the surface under consideration; often, the surface is curved, possessing complicated structure and possibly singularities. Numerical simulations commonly are based on approximate, rather than exact, discretizations of these surfaces. To assess the strength of the dependence of simulation accuracy on the fidelity of surface representation, here methods were developed to model several important surface formulations using exact surface discretizations. Following and refining Zauhar's work [J. Comput.-Aided Mol. Des. 9, 149 (1995)], two classes of curved elements were defined that can exactly discretize the van der Waals, solvent-accessible, and solvent-excluded (molecular) surfaces. Numerical integration techniques are presented that can accurately evaluate nonsingular and singular integrals over these curved surfaces. After validating the exactness of the surface discretizations and demonstrating the correctness of the presented integration methods, a set of calculations are presented that compare the accuracy of approximate, planar-triangle-based discretizations and exact, curved-element-based simulations of surface-generalized-Born (sGB), surface-continuum van der Waals (scvdW), and boundary-element method (BEM) electrostatics problems. Results demonstrate that continuum electrostatic calculations with BEM using curved elements, piecewise-constant basis functions, and centroid collocation are nearly ten times more accurate than planar-triangle BEM for basis sets of comparable size. The sGB and scvdW calculations give exceptional accuracy even for the coarsest obtainable discretized surfaces. The extra accuracy is attributed to the exact representation of the solute-solvent interface; in contrast, commonly used planar-triangle discretizations can only offer improved approximations with increasing discretization and associated increases in computational resources. The results clearly demonstrate that the methods for approximate integration on an exact geometry are far more accurate than exact integration on an approximate geometry. A MATLAB implementation of the presented integration methods and sample data files containing curved-element discretizations of several small molecules are available online as supplemental material.

A combined approach for the evaluation of a volatile organic compound emissions inventory.

PubMed

Choi, Yu-Jin; Calabrese, Richard V; Ehrman, Sheryl H; Dickerson, Russell R; Stehr, Jeffrey W

2006-02-01

Emissions inventories significantly affect photochemical air quality model performance and the development of effective control strategies. However, there have been very few studies to evaluate their accuracy. Here, to evaluate a volatile organic compound (VOC) emissions inventory, we implemented a combined approach: comparing the ratios of carbon bond (CB)-IV VOC groups to nitrogen oxides (NOx) or carbon monoxide (CO) using an emission preprocessing model, comparing the ratios of VOC source contributions from a source apportionment technique to NOx or CO, and comparing ratios of CB-IV VOC groups to NOx or CO and the absolute concentrations of CB-IV VOC groups using an air quality model, with the corresponding ratios and concentrations observed at three sites (Maryland, Washington, DC, and New Jersey). The comparisons of the ethene/NOx ratio, the xylene group (XYL)/NOx ratio, and ethene and XYL concentrations between estimates and measurements showed some differences, depending on the comparison approach, at the Maryland and Washington, DC sites. On the other hand, consistent results at the New Jersey site were observed, implying a possible overestimation of vehicle exhaust. However, in the case of the toluene group (TOL), which is emitted mainly from surface coating and printing sources in the solvent utilization category, the ratios of TOL/ NOx or CO, as well as the absolute concentrations revealed an overestimate of these solvent sources by a factor of 1.5 to 3 at all three sites. In addition, the overestimate of these solvent sources agreed with the comparisons of surface coating and printing source contributions relative to NOx from a source apportionment technique to the corresponding value of estimates at the Maryland site. Other studies have also suggested an overestimate of solvent sources, implying a possibility of inaccurate emission factors in estimating VOC emissions from surface coating and printing sources. We tested the impact of these overestimates with a chemical transport model and found little change in ozone but substantial changes in calculated secondary organic aerosol concentrations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moyer, Bruce A.

The North American industry has employed major solvent-extraction processes to support a wide range of separations including but not limited to chemical, metallurgical, nuclear, biochemical, pharmaceutical, and petroleum applications. The knowledge enabling these separations has been obtained through fundamental studies in academe, government and industry. The International Solvent Extraction Conferences have been and continue to be a major gathering of scientists, engineers, operators, and vendors from around the world, who present new findings since the last meeting, exchange ideas, make business contacts, and conduct collegial discussions. The ISEC 2008 program emphasizes fundamentals to industrial applications of solvent extraction, particularly howmore » this broad spectrum of activities is interconnected and has led to the implementation of novel processes. The oral and poster sessions have been organized into seven topics: Fundamentals; Novel Reagents, Materials and Techniques; Nuclear Fuel Reprocessing; Hydrometallurgy and Metals Extraction; Analytical and Preparative Applications; Biotechnology, Pharmaceuticals, Life-Science Products, and Organic Products; and Process Chemistry and Engineering. Over 350 abstracts were received, resulting in more than 260 manuscripts published in these proceedings. Five outstanding plenary presentations have been identified, with five parallel sessions for oral presentations and posters. In recognition of the major role solvent extraction (SX) plays in the hydrometallurgical and nuclear industries, these proceedings begin with sections focusing on hydrometallurgy, process chemistry, and engineering. More fundamental topics follow, including sections on novel reagents, materials, and techniques, featuring novel applications in analytical and biotechnology areas. Despite the diversity of topics and ideas represented, however, the primary focus of the ISEC community continues to be metals extraction. Four papers from these proceedings have been entered already in INIS in the form of individual reports. Among the remaining papers, 60 have been selected from the following sessions: Plenary Lectures, Hydrometallurgy and Metals Extraction, Nuclear Fuel Reprocessing, Analytical and Preparative Applications, Fundamentals, and Novel Reagents, Materials, and Techniques.« less

Far-ultraviolet absorbance detection of sugars and peptides by high-performance liquid chromatography.

PubMed

Uchiho, Yuichi; Goto, Yusuke; Kamahori, Masao; Aota, Toshimichi; Morisaki, Atsuki; Hosen, Yusuke; Koda, Kimiyoshi

2015-12-11

A far-ultraviolet (FUV)-absorbance detector with a transmission flow cell was developed and applied to detect absorbance of sugars and peptides by HPLC. The main inherent limitation of FUV-absorbance detection is the strong absorptions of solvents and atmospheric oxygen in the optical system as well as dissolved oxygen in the solvent. High absorptivity of the solvent and oxygen decreases transmission-light intensity in the flow cell and hinders the absorbance measurement. To solve the above drawbacks, the transmission-light intensity in the flow cell was increased by introducing a new optical system and a nitrogen-purging unit to remove the atmospheric oxygen. The optical system has a photodiode for detecting the reference light at a position of the minus-first-order diffracted light. In addition, acetonitrile and water were selected as usable solvents because of their low absorptivity in the FUV region. As a result of these implementations, the detectable wavelength of the FUV-absorbance detector (with a flow cell having an effective optical path length of 0.5mm) can be extended down to 175nm. Three sugars (glucose, fructose, and sucrose) were successfully detected with the FUV-absorbance detector. These detection results reveal that the absorption peak of sugar in liquid phase lies at around 178nm. The detection limit (S/N=3) in absorbance with a 0.5-mm flow cell at 180nm was 21μAU, which corresponds to 33, 60 and 60μM (198, 360, and 360pmol) for fructose, glucose, and sucrose, respectively. Also, the peptide Met-enkephalin could be detected with a high sensitivity at 190nm. The estimated detection limit (S/N=3) for Met-enkephalin is 29nM (0.29pmol), which is eight times lower than that at 220nm. Copyright © 2015 Elsevier B.V. All rights reserved.

Performance of the AMOEBA Water Model in the Vicinity of QM Solutes: A Diagnosis Using Energy Decomposition Analysis.

PubMed

Mao, Yuezhi; Shao, Yihan; Dziedzic, Jacek; Skylaris, Chris-Kriton; Head-Gordon, Teresa; Head-Gordon, Martin

2017-05-09

The importance of incorporating solvent polarization effects into the modeling of solvation processes has been well-recognized, and therefore a new generation of hybrid quantum mechanics/molecular mechanics (QM/MM) approaches that accounts for this effect is desirable. We present a fully self-consistent, mutually polarizable QM/MM scheme using the AMOEBA force field, in which the total energy of the system is variationally minimized with respect to both the QM electronic density and the MM induced dipoles. This QM/AMOEBA model is implemented through the Q-Chem/LibEFP code interface and then applied to the evaluation of solute-solvent interaction energies for various systems ranging from the water dimer to neutral and ionic solutes (NH 3 , NH 4 + , CN - ) surrounded by increasing numbers of water molecules (up to 100). In order to analyze the resulting interaction energies, we also utilize an energy decomposition analysis (EDA) scheme which identifies contributions from permanent electrostatics, polarization, and van der Waals (vdW) interaction for the interaction between the QM solute and the solvent molecules described by AMOEBA. This facilitates a component-wise comparison against full QM calculations where the corresponding energy components are obtained via a modified version of the absolutely localized molecular orbitals (ALMO)-EDA. The results show that the present QM/AMOEBA model can yield reasonable solute-solvent interaction energies for neutral and cationic species, while further scrutiny reveals that this accuracy highly relies on the delicate balance between insufficiently favorable permanent electrostatics and softened vdW interaction. For anionic solutes where the charge penetration effect becomes more pronounced, the QM/MM interface turns out to be unbalanced. These results are consistent with and further elucidate our findings in a previous study using a slightly different QM/AMOEBA model ( Dziedzic et al. J. Chem. Phys. 2016 , 145 , 124106 ). The implications of these results for further refinement of this model are also discussed.

Evaluation of ionic liquids as alternative solvents for aldolase activity: Use of a new automated SIA methodology.

PubMed

Cunha, Edite; Pinto, Paula C A G; Saraiva, M Lúcia M F S

2015-08-15

An automated methodology is proposed for the evaluation of a set of ionic liquids (ILs) as alternative reaction media for aldolase based synthetic processes. For that, the effect of traditionally used organic solvents and ILs on the activity of aldolase was studied by means of a novel automated methodology. The implemented methodology is based on the concept of sequential injection analysis (SIA) and relies on the aldolase based cleavage of d-fructose-1,6 diphosphate (DFDP), to produce dihydroxyacetone phosphate (DHAP) and d-glyceraldehyde-3-phosphate (G3P). In the presence of FeCl3, 3-methyl-2-benzothiazoline hydrazine (MBTH) forms a blue cation that can be measured at 670nm, by combination with G3P. The influence of several parameters such as substrate and enzyme concentration, temperature, delay time and MBTH and FeCl3 concentration were studied and the optimum reaction conditions were subsequently selected. The developed methodology showed good precision and a relative standard deviation (rsd) that does not exceed 7% also leading to low reagents consumption as well as effluent production. Resorting to this strategy, the activity of the enzyme was studied in strictly aqueous media and in the presence of dimethylformamide, methanol, bmpyr [Cl], hmim [Cl], bmim [BF4], emim [BF4], emim [Ac], bmim [Cl], emim [TfMs], emim [Ms] and Chol [Ac] up to 50%. The results show that the utilization of ILs as reaction media for aldolase based organic synthesis might present potential advantages over the tested conventional organic solvents. The least toxic IL found in this study was cho [Ac] that causes a reduction of enzyme activity of only 2.7% when used in a concentration of 50%. Generally, it can be concluded that ILs based on choline or short alkyl imidazolium moieties associated with biocompatible anions are the most promising ILs regarding the future inclusion of these solvents in synthetic protocols catalyzed by aldolase. Copyright © 2015 Elsevier B.V. All rights reserved.

Distributed numerical controllers

NASA Astrophysics Data System (ADS)

Orban, Peter E.

2001-12-01

While the basic principles of Numerical Controllers (NC) have not changed much during the years, the implementation of NCs' has changed tremendously. NC equipment has evolved from yesterday's hard-wired specialty control apparatus to today's graphics intensive, networked, increasingly PC based open systems, controlling a wide variety of industrial equipment with positioning needs. One of the newest trends in NC technology is the distributed implementation of the controllers. Distributed implementation promises to offer robustness, lower implementation costs, and a scalable architecture. Historically partitioning has been done along the hierarchical levels, moving individual modules into self contained units. The paper discusses various NC architectures, the underlying technology for distributed implementation, and relevant design issues. First the functional requirements of individual NC modules are analyzed. Module functionality, cycle times, and data requirements are examined. Next the infrastructure for distributed node implementation is reviewed. Various communication protocols and distributed real-time operating system issues are investigated and compared. Finally, a different, vertical system partitioning, offering true scalability and reconfigurability is presented.

48 CFR 47.403 - Guidelines for implementation of the Fly America Act.

Code of Federal Regulations, 2014 CFR

2014-10-01

... implementation of the Fly America Act. 47.403 Section 47.403 Federal Acquisition Regulations System FEDERAL... Guidelines for implementation of the Fly America Act. This section 47.403 is based on the Guidelines for Implementation of the Fly America Act (case number B-138942), issued by the Comptroller General of the United...

48 CFR 47.403 - Guidelines for implementation of the Fly America Act.

Code of Federal Regulations, 2011 CFR

2011-10-01

... implementation of the Fly America Act. 47.403 Section 47.403 Federal Acquisition Regulations System FEDERAL... Guidelines for implementation of the Fly America Act. This section 47.403 is based on the Guidelines for Implementation of the Fly America Act (case number B-138942), issued by the Comptroller General of the United...

48 CFR 47.403 - Guidelines for implementation of the Fly America Act.

Code of Federal Regulations, 2012 CFR

2012-10-01

... implementation of the Fly America Act. 47.403 Section 47.403 Federal Acquisition Regulations System FEDERAL... Guidelines for implementation of the Fly America Act. This section 47.403 is based on the Guidelines for Implementation of the Fly America Act (case number B-138942), issued by the Comptroller General of the United...

48 CFR 47.403 - Guidelines for implementation of the Fly America Act.

Code of Federal Regulations, 2013 CFR

2013-10-01

... implementation of the Fly America Act. 47.403 Section 47.403 Federal Acquisition Regulations System FEDERAL... Guidelines for implementation of the Fly America Act. This section 47.403 is based on the Guidelines for Implementation of the Fly America Act (case number B-138942), issued by the Comptroller General of the United...

Understanding and avoiding potential problems in implementing automation

NASA Astrophysics Data System (ADS)

Rouse, W. B.; Morris, N. M.

1985-11-01

Technology-driven efforts to implement automation often encounter problems due to lack of acceptance or begrudging acceptance by the personnel involved. It is argued in this paper that the level of automation perceived by an individual heavily influences whether or not the automation is accepted by that individual. The factors that appear to affect perceived level of automation are discussed. Issues considered include the impact of automation on the system and the individual, correlates of acceptance, problems and risks of automation, and factors influencing alienation. Based on an understanding of these issues, a set of eight guidelines is proposed as a possible means of avoiding problems in implementing automation.

Understanding and avoiding potential problems in implementing automation

NASA Technical Reports Server (NTRS)

Rouse, W. B.; Morris, N. M.

1985-01-01

Technology-driven efforts to implement automation often encounter problems due to lack of acceptance or begrudging acceptance by the personnel involved. It is argued in this paper that the level of automation perceived by an individual heavily influences whether or not the automation is accepted by that individual. The factors that appear to affect perceived level of automation are discussed. Issues considered include the impact of automation on the system and the individual, correlates of acceptance, problems and risks of automation, and factors influencing alienation. Based on an understanding of these issues, a set of eight guidelines is proposed as a possible means of avoiding problems in implementing automation.

The Efficacy of Psychophysiological Measures for Implementing Adaptive Technology

NASA Technical Reports Server (NTRS)

Scerbo, Mark W.; Freeman, Frederick G.; Mikulka, Peter J.; Parasuraman, Raja; DiNocero, Francesco; Prinzel, Lawrence J., III

2001-01-01

Adaptive automation refers to technology that can change its mode of operation dynamically. Further, both the technology and the operator can initiate changes in the level or mode of automation. The present paper reviews research on adaptive technology. It is divided into three primary sections. In the first section, issues surrounding the development and implementation of adaptive automation are presented. Because physiological-based measures show much promise for implementing adaptive automation, the second section is devoted to examining candidate indices. In the final section, those techniques that show the greatest promise for adaptive automation as well as issues that still need to be resolved are discussed.

Issues in providing a reliable multicast facility

NASA Technical Reports Server (NTRS)

Dempsey, Bert J.; Strayer, W. Timothy; Weaver, Alfred C.

1990-01-01

Issues involved in point-to-multipoint communication are presented and the literature for proposed solutions and approaches surveyed. Particular attention is focused on the ideas and implementations that align with the requirements of the environment of interest. The attributes of multicast receiver groups that might lead to useful classifications, what the functionality of a management scheme should be, and how the group management module can be implemented are examined. The services that multicasting facilities can offer are presented, followed by mechanisms within the communications protocol that implements these services. The metrics of interest when evaluating a reliable multicast facility are identified and applied to four transport layer protocols that incorporate reliable multicast.

Rational enhancement of enzyme performance in organic solvents. Final technical report, 1992--1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klibanov, A.M.

1996-12-31

This research focused on the following: the dependence of enzymatic activity of several model hydrolases in nonaqueous solvents; control of substrate selectivity of the protease subtilisin Carlsberg by the solvent; control of catalytic activity and enantioselectivity of this enzyme in organic solvents by immobilization support; lipase-catalyzed acylation of sugars in anhydrous hydrophobic media; the possibility of accelerating enzymatic processes in organic solvents by certain cosolvents; whether lipase catalysis in organic solvents can be enhanced by introducing interfaces in the in the reaction medium; the structure of proteins suspended in organic solvents; improving enzymatic enantioselectivity in organic solvents; analyzing the plungemore » in enzymatic activity upon replacing water with organic solvents; and the structural basis for the phenomenon of molecular memory of imprinted proteins in organic solvents.« less

Organic Solvent Effects in Biomass Conversion Reactions.

PubMed

Shuai, Li; Luterbacher, Jeremy

2016-01-01

Transforming lignocellulosic biomass into fuels and chemicals has been intensely studied in recent years. A large amount of work has been dedicated to finding suitable solvent systems, which can improve the transformation of biomass into value-added chemicals. These efforts have been undertaken based on numerous research results that have shown that organic solvents can improve both conversion and selectivity of biomass to platform molecules. We present an overview of these organic solvent effects, which are harnessed in biomass conversion processes, including conversion of biomass to sugars, conversion of sugars to furanic compounds, and production of lignin monomers. A special emphasis is placed on comparing the solvent effects on conversion and product selectivity in water with those in organic solvents while discussing the origins of the differences that arise. We have categorized results as benefiting from two major types of effects: solvent effects on solubility of biomass components including cellulose and lignin and solvent effects on chemical thermodynamics including those affecting reactants, intermediates, products, and/or catalysts. Finally, the challenges of using organic solvents in industrial processes are discussed from the perspective of solvent cost, solvent stability, and solvent safety. We suggest that a holistic view of solvent effects, the mechanistic elucidation of these effects, and the careful consideration of the challenges associated with solvent use could assist researchers in choosing and designing improved solvent systems for targeted biomass conversion processes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Teacher Professional Development Model for Teaching Socioscientific Issues

ERIC Educational Resources Information Center

Carson, Katherine; Dawson, Vaille

2016-01-01

This paper describes the development and implementation of a three-pillared model for teaching socioscientific issues: teacher professional development; curriculum resources; and classroom support. A professional development program and curriculum resource based on the socioscientific issue of climate change was trialled with 75 Western Australian…

32 CFR 199.1 - General provisions.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., management control and coordination as required for CHAMPUS, and to develop, issue, and maintain regulations..., to consult with the Secretary of Defense or a designee and to approve and issue joint regulations... an issue joint regulations implementing 10 U.S.C., chapter 55. (iv) Office of CHAMPUS (OCHAMPUS). By...