Sample records for catalysis final technical

  1. Program and Abstracts, Boron Americas IX Final Report

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

    Feakes, Debra A.

    The Scientific and Technical Information (STI) submitted includes the final report and a collection of abstracts for the Ninth Boron in the Americas Conference which was held May 19-22, 2004, in San Marcos, Texas. The topics covered in the abstracts include: Application in Medicine, Application in Organic Synthesis and Catalysis, Boranes and Carboranes, Materials and Polymers, Metallaboranes and Metallacarboranes, Organoboron Compounds, Synthesis and Catalysis, and Theoretical Studies. Attendees represented researchers from government, industry, and academia.

  2. DOE Award No. FG02-93ER14331 Final Technical Report

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

    Bartynski, Robert

    We have studyed new aspects of the relationships between nanoscale surface features and heterogeneous catalysis or electrocatalysis. We concentrate on atomically rough and morphologically unstable surfaces of catalytic metal single crystals (Re, Ru, Ir) that undergo nanoscale faceting when interacting with strongly adsorbed species (e.g. O, N, C) at elevated temperatures.

  3. Final Technical Report

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

    Spivey, James J.

    The research summarized here has the goal of developing a fundamental understanding of how catalysts work. These materials are demonstrably essential to our daily life, from the cars we drive to the clothes we wear. Our Center advances the science behind how we prepare, analyze, and describe catalysts. This has been identified by one of the documents guiding Federal research objectives (Directing Matter and Energy: Five Challenges for Science and the Imagination): “Major challenges in heterogeneous catalysis are to more clearly define the nature of the active sites, to engineer at the molecular level catalysis with designed properties in threemore » dimensions, and to create new catalysts for new transformations.” This directly addresses this objective.« less

  4. Final Report on Kokes Awards for the 20th North American Catalysis Society Meeting

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

    Wong, Michael S

    2008-12-31

    This Final Report describes how the Kokes Awards program was carried out for the 2007 meeting with regard to selection of students and disbursement of funds received from DOE and other sources. The objective of the Richard J. Kokes Travel Award program of the American Catalysis Society is to encourage graduate students to attend and participate meaningfully in the biennial North American Catalysis Society Meeting.

  5. Catalysis and biocatalysis program

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The annual report presents the fiscal year (FY) 1990 research activities and accomplishments for the Catalysis and Biocatalysis Program of the Advanced Industrial Concepts Division (AICD), Office of Industrial Technologies of the Department of Energy (DOE). The mission of the AICD is to create a balanced program of high risk, long term, directed interdisciplinary research and development that will improve energy efficiency and enhance fuel flexibility in the industrial sector. The Catalysis and Biocatalysis Program's technical activities were organized into five work elements: the Molecular Modeling and Catalysis by Design element; the Applied Microbiology and Genetics element; the Bioprocess Engineering element; the Separations and Novel Chemical Processes element; and the Process Design and Analysis element.

  6. Reactor for tracking catalyst nanoparticles in liquid at high temperature under a high-pressure gas phase with X-ray absorption spectroscopy.

    PubMed

    Nguyen, Luan; Tao, Franklin Feng

    2018-02-01

    Structure of catalyst nanoparticles dispersed in liquid phase at high temperature under gas phase of reactant(s) at higher pressure (≥5 bars) is important for fundamental understanding of catalytic reactions performed on these catalyst nanoparticles. Most structural characterizations of a catalyst performing catalysis in liquid at high temperature under gas phase at high pressure were performed in an ex situ condition in terms of characterizations before or after catalysis since, from technical point of view, access to the catalyst nanoparticles during catalysis in liquid phase at high temperature under high pressure reactant gas is challenging. Here we designed a reactor which allows us to perform structural characterization using X-ray absorption spectroscopy including X-ray absorption near edge structure spectroscopy and extended X-ray absorption fine structure spectroscopy to study catalyst nanoparticles under harsh catalysis conditions in terms of liquid up to 350 °C under gas phase with a pressure up to 50 bars. This reactor remains nanoparticles of a catalyst homogeneously dispersed in liquid during catalysis and X-ray absorption spectroscopy characterization.

  7. Final Technical Report: Metal—Organic Surface Catalyst for Low-temperature Methane Oxidation: Bi-functional Union of Metal—Organic Complex and Chemically Complementary Surface

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

    Tait, Steven L.

    Stabilization and chemical control of transition metal centers is a critical problem in the advancement of heterogeneous catalysts to next-generation catalysts that exhibit high levels of selectivity, while maintaining strong activity and facile catalyst recycling. Supported metal nanoparticle catalysts typically suffer from having a wide range of metal sites with different coordination numbers and varying chemistry. This project is exploring new possibilities in catalysis by combining features of homogeneous catalysts with those of heterogeneous catalysts to develop new, bi-functional systems. The systems are more complex than traditional heterogeneous catalysts in that they utilize sequential active sites to accomplish the desiredmore » overall reaction. The interaction of metal—organic catalysts with surface supports and their interactions with reactants to enable the catalysis of critical reactions at lower temperatures are at the focus of this study. Our work targets key fundamental chemistry problems. How do the metal—organic complexes interact with the surface? Can those metal center sites be tuned for selectivity and activity as they are in the homogeneous system by ligand design? What steps are necessary to enable a cooperative chemistry to occur and open opportunities for bi-functional catalyst systems? Study of these systems will develop the concept of bringing together the advantages of heterogeneous catalysis with those of homogeneous catalysis, and take this a step further by pursuing the objective of a bi-functional system. The use of metal-organic complexes in surface catalysts is therefore of interest to create well-defined and highly regular single-site centers. While these are not likely to be stable in the high temperature environments (> 300 °C) typical of industrial heterogeneous catalysts, they could be applied in moderate temperature reactions (100-300 °C), made feasible by lowering reaction temperatures by better catalyst control. They also serve as easily tuned model systems for exploring the chemistry of single-site transition metals and tandem catalysts that could then be developed into a zeolite or other stable support structures. In this final technical report, three major advances our described that further these goals. The first is a study demonstrating the ability to tune the oxidation state of V single-site centers on a surface by design of the surrounding ligand field. The synthesis of the single-site centers was developed in a previous reporting period of this project and this new advance shows a distinct new ability of the systems to have a designed oxidation state of the metal center. Second, we demonstrate metal complexation at surfaces using vibrational spectroscopy and also show a metal replacement reaction on Ag surfaces. Third, we demonstrate a surface-catalyzed dehydrocyclization reaction important for metal-organic catalyst design at surfaces.« less

  8. Photon catalysis acting as noiseless linear amplification and its application in coherence enhancement

    NASA Astrophysics Data System (ADS)

    Zhang, Shengli; Zhang, Xiangdong

    2018-04-01

    Photon catalysis is an intriguing quantum mechanical operation during which no photon is added to or subtracted from the relevant optical system. However, we prove that photon catalysis is in essence equivalent to the simpler but more efficient noiseless linear amplifier. This provides a simple and zero-energy-input method for enhancing quantum coherence. We show that the coherence enhancement holds both for a coherent state and a two-mode squeezed vacuum (TMSV) state. For the TMSV state, biside photon catalysis is shown to be equivalent to two times the single-side photon catalysis, and two times the photon catalysis does not provide a substantial enhancement of quantum coherence compared with single-side catalysis. We further extend our investigation to the performance of coherence enhancement with a more realistic photon catalysis scheme where a heralded approximated single-photon state and an on-off detector are exploited. Moreover, we investigate the influence of an imperfect photon detector and the result shows that the amplification effect of photon catalysis is insensitive to the detector inefficiency. Finally, we apply the coherence measure to quantum illumination and see the same trend of performance improvement as coherence enhancement is identified in practical quantum target detection.

  9. ENZYMATIC CATALYSIS OF FORMATION OF Z-ASPARTAME IN IONIC LIQUID: AN ALTERNATIVE TO ENZYMATIC CATALYSIS IN ORGANIC SOLVENTS. (R828131)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  10. Operando chemistry of catalyst surfaces during catalysis.

    PubMed

    Dou, Jian; Sun, Zaicheng; Opalade, Adedamola A; Wang, Nan; Fu, Wensheng; Tao, Franklin Feng

    2017-04-03

    Chemistry of a catalyst surface during catalysis is crucial for a fundamental understanding of mechanism of a catalytic reaction performed on the catalyst in the gas or liquid phase. Due to the pressure- or molecular density-dependent entropy contribution of gas or liquid phase of the reactants and the potential formation of a catalyst surface during catalysis different from that observed in an ex situ condition, the characterization of the surface of a catalyst under reaction conditions and during catalysis can be significant and even necessary for understanding the catalytic mechanism at a molecular level. Electron-based analytical techniques are challenging for studying catalyst nanoparticles in the gas or liquid phase although they are necessary techniques to employ. Instrumentation and further development of these electron-based techniques have now made in situ/operando studies of catalysts possible. New insights into the chemistry and structure of catalyst nanoparticles have been uncovered over the last decades. Herein, the origin of the differences between ex situ and in situ/operando studies of catalysts, and the technical challenges faced as well as the corresponding instrumentation and innovations utilized for characterizing catalysts under reaction conditions and during catalysis, are discussed. The restructuring of catalyst surfaces driven by the pressure of reactant(s) around a catalyst, restructuring in reactant(s) driven by reaction temperature and restructuring during catalysis are also reviewed herein. The remaining challenges and possible solutions are briefly discussed.

  11. Virtual Special Issue on Catalysis at the U.S. Department of Energy’s National Laboratories

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

    Pruski, Marek; Sadow, Aaron; Slowing, Igor

    Catalysis research at the U.S. Department of Energy's (DOE's) National Laboratories covers a wide range of research topics in heterogeneous catalysis, homogeneous/ molecular catalysis, electrocatalysis, and surface science. Since much of the work at National Laboratories is funded by DOE, the research is largely focused on addressing DOE’s mission to ensure America’s security and prosperity by addressing its energy, environmental, and nuclear challenges through trans-formative science and technology solutions. The catalysis research carried out at the DOE National Laboratories ranges from very fundamental catalysis science, funded by DOE’s Office of Basic Energy Sciences (BES), to applied research and development (R&D)more » in areas such as biomass conversion to fuels and chemicals, fuel cells, and vehicle emission control with primary funding from DOE’s Office of Energy Efficiency and Renewable Energy. National Laboratories are home to many DOE Office of Science national scientific user facilities that provide researchers with the most advanced tools of modern science, including accelerators, colliders, supercomputers, light sources, and neutron sources, as well as facilities for studying the nanoworld and the terrestrial environment. National Laboratory research programs typically feature teams of researchers working closely together, often joining scientists from different disciplines to attack scientific and technical problems using a variety of tools and techniques available at the DOE national scientific user facilities. Along with collaboration between National Laboratory scientists, interactions with university colleagues are common in National Laboratory catalysis R&D. In some cases, scientists have joint appoint-ments at a university and a National Laboratory.« less

  12. Virtual Special Issue on Catalysis at the U.S. Department of Energy’s National Laboratories

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

    Pruski, Marek; Sadow, Aaron D.; Slowing, Igor I.

    Catalysis research at the U.S. Department of Energy’s (DOE’s) National Laboratories covers a wide range of research topics in heterogeneous catalysis, homogeneous/molecular catalysis, biocatalysis, electrocatalysis, and surface science. Since much of the work at National Laboratories is funded by DOE, the research is largely focused on addressing DOE’s mission to ensure America’s security and prosperity by addressing its energy, environmental, and nuclear challenges through transformative science and technology solutions. The catalysis research carried out at the DOE National Laboratories ranges from very fundamental catalysis science, funded by DOE’s Office of Basic Energy Sciences (BES), to applied research and development (R&D)more » in areas such as biomass conversion to fuels and chemicals, fuel cells, and vehicle emission control with primary funding from DOE’s Office of Energy Efficiency and Renewable Energy. National Laboratories are home to many DOE Office of Science national scientific user facilities that provide researchers with the most advanced tools of modern science, including accelerators, colliders, supercomputers, light sources, and neutron sources, as well as facilities for studying the nanoworld and the terrestrial environment. National Laboratory research programs typically feature teams of researchers working closely together, often joining scientists from different disciplines to tackle scientific and technical problems using a variety of tools and techniques available at the DOE national scientific user facilities. Along with collaboration between National Laboratory scientists, interactions with university colleagues are common in National Laboratory catalysis R&D. In some cases, scientists have joint appointments at a university and a National Laboratory.« less

  13. 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

  14. Polymer Electrolyte Through Enzyme Catalysis for High Performance Lithium-Ion Batteries

    DTIC Science & Technology

    1998-10-16

    by block number) FIELD GROUP SUB-GROUP Polymer Electrolyte, Solid State, Enzyme Catalysis, Lithium - Ion Battery , Sol Gel, High Conductivity 19...excellent candidates for lithium - ion battery development. Furthermore, the processes used to achieve the final product yield very good mechanical properties...Objectives This research was initiated to investigate synthesis of improved polymer electrolytes for lithium - ion battery applications. The overall

  15. FINAL Progress Report DOE Grant DE-FG02-04ER15587

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

    Mullins, Charles Buddie

    Catalysis Program - Viviane Schwartz Program Manager This Final Report discusses several archival journal articles that have been published that present and discuss the results that were discovered through this DOE grant.

  16. Oxidation Catalysts in the Dark and the Light

    DTIC Science & Technology

    2010-01-01

    TiO2 with added silver, chromium, vanadium, manganese, carbon, and/or sulfur (selected transition metal ions and selected non- metals ) are very...Ranjit, Koodali T.; Klabunde, Kenneth J.; “ Catalysis by Metal Oxides,” Surface and Nanomolecular Catalysis , ed. Ryan Richards, CRC Press, NY, Ch. 2, pgs...REPORT Oxidation Catalysts in the Dark and the Light--Final Report 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: Extensive research on mixed metal oxide

  17. Photochemistry of Cobalt Carbonyl Complexes having a Cobalt-Silicon Bond and its Importance in Activation of Catalysis.

    DTIC Science & Technology

    1980-08-22

    CLASS. (*I *Soi rapeoro 7_ UNCLASSIFIED / ...--J I.. ECk ASSI FICATION/ DOWNGRADING 16. DISTRIBUTION STATEMENT (of thnis Asport) Approved for public...Defense Technical Information Center Attn: Dr. S. Yamamoto, Marine Building 5, Cameron Station Sciences Division Alexandria, Virginia 22314 12 San Diego

  18. Metal-organic frameworks: versatile heterogeneous catalysts for efficient catalytic organic transformations.

    PubMed

    Chughtai, Adeel H; Ahmad, Nazir; Younus, Hussein A; Laypkov, A; Verpoort, Francis

    2015-10-07

    Novel catalytic materials are highly demanded to perform a variety of catalytic organic reactions. MOFs combine the benefits of heterogeneous catalysis like easy post reaction separation, catalyst reusability, high stability and homogeneous catalysis such as high efficiency, selectivity, controllability and mild reaction conditions. The possible organization of active centers like metallic nodes, organic linkers, and their chemical synthetic functionalization on the nanoscale shows potential to build up MOFs particularly modified for catalytic challenges. In this review, we have summarized the recent research progress in heterogeneous catalysis by MOFs and their catalytic behavior in various organic reactions, highlighting the key features of MOFs as catalysts based on the active sites in the framework. Examples of their post functionalization, inclusion of active guest species and metal nanoparticles have been discussed. Finally, the use of MOFs as catalysts for asymmetric heterogeneous catalysis and stability of MOFs has been presented as separate sections.

  19. Computational predictions of the new Gallium nitride nanoporous structures

    NASA Astrophysics Data System (ADS)

    Lien, Le Thi Hong; Tuoc, Vu Ngoc; Duong, Do Thi; Thu Huyen, Nguyen

    2018-05-01

    Nanoporous structural prediction is emerging area of research because of their advantages for a wide range of materials science and technology applications in opto-electronics, environment, sensors, shape-selective and bio-catalysis, to name just a few. We propose a computationally and technically feasible approach for predicting Gallium nitride nanoporous structures with hollows at the nano scale. The designed porous structures are studied with computations using the density functional tight binding (DFTB) and conventional density functional theory methods, revealing a variety of promising mechanical and electronic properties, which can potentially find future realistic applications. Their stability is discussed by means of the free energy computed within the lattice-dynamics approach. Our calculations also indicate that all the reported hollow structures are wide band gap semiconductors in the same fashion with their parent’s bulk stable phase. The electronic band structures of these nanoporous structures are finally examined in detail.

  20. Single-molecule Force Spectroscopy Approach to Enzyme Catalysis*

    PubMed Central

    Alegre-Cebollada, Jorge; Perez-Jimenez, Raul; Kosuri, Pallav; Fernandez, Julio M.

    2010-01-01

    Enzyme catalysis has been traditionally studied using a diverse set of techniques such as bulk biochemistry, x-ray crystallography, and NMR. Recently, single-molecule force spectroscopy by atomic force microscopy has been used as a new tool to study the catalytic properties of an enzyme. In this approach, a mechanical force ranging up to hundreds of piconewtons is applied to the substrate of an enzymatic reaction, altering the conformational energy of the substrate-enzyme interactions during catalysis. From these measurements, the force dependence of an enzymatic reaction can be determined. The force dependence provides valuable new information about the dynamics of enzyme catalysis with sub-angstrom resolution, a feat unmatched by any other current technique. To date, single-molecule force spectroscopy has been applied to gain insight into the reduction of disulfide bonds by different enzymes of the thioredoxin family. This minireview aims to present a perspective on this new approach to study enzyme catalysis and to summarize the results that have already been obtained from it. Finally, the specific requirements that must be fulfilled to apply this new methodology to any other enzyme will be discussed. PMID:20382731

  1. Single-molecule force spectroscopy approach to enzyme catalysis.

    PubMed

    Alegre-Cebollada, Jorge; Perez-Jimenez, Raul; Kosuri, Pallav; Fernandez, Julio M

    2010-06-18

    Enzyme catalysis has been traditionally studied using a diverse set of techniques such as bulk biochemistry, x-ray crystallography, and NMR. Recently, single-molecule force spectroscopy by atomic force microscopy has been used as a new tool to study the catalytic properties of an enzyme. In this approach, a mechanical force ranging up to hundreds of piconewtons is applied to the substrate of an enzymatic reaction, altering the conformational energy of the substrate-enzyme interactions during catalysis. From these measurements, the force dependence of an enzymatic reaction can be determined. The force dependence provides valuable new information about the dynamics of enzyme catalysis with sub-angstrom resolution, a feat unmatched by any other current technique. To date, single-molecule force spectroscopy has been applied to gain insight into the reduction of disulfide bonds by different enzymes of the thioredoxin family. This minireview aims to present a perspective on this new approach to study enzyme catalysis and to summarize the results that have already been obtained from it. Finally, the specific requirements that must be fulfilled to apply this new methodology to any other enzyme will be discussed.

  2. Catalysis by dihydrofolate reductase and other enzymes arises from electrostatic preorganization, not conformational motions

    PubMed Central

    Adamczyk, Andrew J.; Cao, Jie; Kamerlin, Shina C. L.; Warshel, Arieh

    2011-01-01

    The proposal that enzymatic catalysis is due to conformational fluctuations has been previously promoted by means of indirect considerations. However, recent works have focused on cases where the relevant motions have components toward distinct conformational regions, whose population could be manipulated by mutations. In particular, a recent work has claimed to provide direct experimental evidence for a dynamical contribution to catalysis in dihydrofolate reductase, where blocking a relevant conformational coordinate was related to the suppression of the motion toward the occluded conformation. The present work utilizes computer simulations to elucidate the true molecular basis for the experimentally observed effect. We start by reproducing the trend in the measured change in catalysis upon mutations (which was assumed to arise as a result of a “dynamical knockout” caused by the mutations). This analysis is performed by calculating the change in the corresponding activation barriers without the need to invoke dynamical effects. We then generate the catalytic landscape of the enzyme and demonstrate that motions in the conformational space do not help drive catalysis. We also discuss the role of flexibility and conformational dynamics in catalysis, once again demonstrating that their role is negligible and that the largest contribution to catalysis arises from electrostatic preorganization. Finally, we point out that the changes in the reaction potential surface modify the reorganization free energy (which includes entropic effects), and such changes in the surface also alter the corresponding motion. However, this motion is never the reason for catalysis, but rather simply a reflection of the shape of the reaction potential surface. PMID:21831831

  3. Quantum Chemical Calculations of Amine-Catalyzed Polymerization of Silanol

    NASA Astrophysics Data System (ADS)

    Gu, Hongyu; Xu, Wenbin; Zhang, Jinlin; Qi, Zhenyi; Zhang, Tao; Song, Lixin

    2018-03-01

    Because of the technical importance of organosilicon materials, insight into the related synthetic processes is significantly essential. In this paper, the amine-catalyzed polymerization of silanol has been investigated by the density functional theory (DFT) method. Our data have shown that amines can catalytically promote the hydrogen transfer process by substantially reducing the energy barrier. The activation barrier via hydrogen transfer with catalysis is 38.32 kJ/mol, much lower than that of catalysis-free process (120.88 kJ/mol). The lower energy barrier is in agreement with the much more intense polymerization of silanols with amine catalysts. Based on the above results, amines and other catalysts capable of assisting hydrogen transfer are expected to be used as catalysts for silanol polymerization.

  4. Molecular catalysis science: Perspective on unifying the fields of catalysis

    DOE PAGES

    Ye, Rong; Hurlburt, Tyler J.; Sabyrov, Kairat; ...

    2016-04-25

    Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nanoparticles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sumfrequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. Itmore » was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and h eterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Finally, unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis.« less

  5. Thermochemical Process Integration, Scale-Up, and Piloting Publications |

    Science.gov Websites

    -Economic Assessment of Ex Situ Catalytic Fast Pyrolysis of Biomass: A Fixed Bed Reactor Implementation Scenario for Future Feasibility, Topics in Catalysis Image of a schematic of hot gas filter and ex situ Research Pathways with In Situ and Ex Situ Upgrading of Fast Pyrolysis Vapors, NREL Technical Report Image

  6. Stable metal-organic frameworks as a host platform for catalysis and biomimetics.

    PubMed

    Qin, Jun-Sheng; Yuan, Shuai; Lollar, Christina; Pang, Jiandong; Alsalme, Ali; Zhou, Hong-Cai

    2018-04-24

    Recent years have witnessed the exploration and synthesis of an increasing number of metal-organic frameworks (MOFs). The utilization of stable MOFs as a platform for catalysis and biomimetics is discussed. This Feature Article will provide insights into the rational design and synthesis of three types of stable MOF catalysts on the basis of structural features of MOFs, that is, (i) MOF catalysts with catalytic sites on metal nodes, (ii) MOF catalysts with catalytic sites immobilized in organic struts, and (iii) MOF catalysts with catalytic centres encapsulated in the pores. Then, MOFs used in biomimetics including biomimetic mineralization, biosensors and biomimetic replication are introduced. Finally, a discussion on the challenges that must be addressed for successful implementation of MOFs in catalysis and biomimetics is presented.

  7. A kinetic study on the catalysis of KCl, K2SO4, and K2CO3 during oxy-biomass combustion.

    PubMed

    Deng, Shuanghui; Wang, Xuebin; Zhang, Jiaye; Liu, Zihan; Mikulčić, Hrvoje; Vujanović, Milan; Tan, Houzhang; Duić, Neven

    2018-07-15

    Biomass combustion under the oxy-fuel conditions (Oxy-biomass combustion) is one of the approaches achieving negative CO 2 emissions. KCl, K 2 CO 3 and K 2 SO 4 , as the major potassium species in biomass ash, can catalytically affect biomass combustion. In this paper, the catalysis of the representative potassium salts on oxy-biomass combustion was studied using a thermogravimetric analyzer (TGA). Effects of potassium salt types (KCl, K 2 CO 3 and K 2 SO 4 ), loading concentrations (0, 1, 3, 5, 8 wt%), replacing N 2 by CO 2 , and O 2 concentrations (5, 20, 30 vol%) on the catalysis degree were discussed. The comparison between TG-DTG curves of biomass combustion before and after water washing in both the 20%O 2 /80%N 2 and 20%O 2 /80%CO 2 atmospheres indicates that the water-soluble minerals in biomass play a role in promoting the devolatilization and accelerating the char-oxidation; and the replacement of N 2 by CO 2 inhibits the devolatilization and char-oxidation processes during oxy-biomass combustion. In the devolatilization stage, the catalysis degree of potassium monotonously increases with the increase of potassium salt loaded concentration. The catalysis degree order of the studied potassium salts is K 2 CO 3  > KCl > K 2 SO 4 . In the char-oxidation stage, with the increase of loading concentration the three kinds of potassium salts present inconsistent change tendencies of the catalysis degree. In the studied loading concentrations from 0 to 8 wt%, there is an optimal loading concentration for KCl and K 2 CO 3 , at 3 and 5 wt%, respectively; while for K 2 SO 4 , the catalysis degree on char-oxidation monotonically increases with the loading potassium concentration. For most studied conditions, regardless of the potassium salt types or the loading concentrations or the combustion stages, the catalysis degree in the O 2 /CO 2 atmosphere is stronger than that in the O 2 /N 2 atmosphere. The catalysis degree is also affected by the O 2 concentrations, and the lowest catalysis degree is generally around 20 vol% O 2 concentration. The kinetic parameters under the different studied conditions are finally obtained. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Advanced electron microscopy characterization of nanomaterials for catalysis

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

    Su, Dong

    Transmission electron microscopy (TEM) has become one of the most powerful techniques in the fields of material science, inorganic chemistry and nanotechnology. In terms of resolutions, advanced TEM may reach a high spatial resolution of 0.05 nm, a high energy-resolution of 7 meV. In addition, in situ TEM can help researcher to image the process happened within 1 ms. This paper reviews the recent technical approaches of applying advanced TEM characterization on nanomaterials for catalysis. The text is organized according to the demanded information of nanocrystals from the perspective of application: for example, size, composition, phase, strain, and morphology. Themore » electron beam induced effect and in situ TEM are also introduced. As a result, I hope this review can help the scientists in related fields to take advantage of advanced TEM to their own researches.« less

  9. Advanced electron microscopy characterization of nanomaterials for catalysis

    DOE PAGES

    Su, Dong

    2017-04-01

    Transmission electron microscopy (TEM) has become one of the most powerful techniques in the fields of material science, inorganic chemistry and nanotechnology. In terms of resolutions, advanced TEM may reach a high spatial resolution of 0.05 nm, a high energy-resolution of 7 meV. In addition, in situ TEM can help researcher to image the process happened within 1 ms. This paper reviews the recent technical approaches of applying advanced TEM characterization on nanomaterials for catalysis. The text is organized according to the demanded information of nanocrystals from the perspective of application: for example, size, composition, phase, strain, and morphology. Themore » electron beam induced effect and in situ TEM are also introduced. As a result, I hope this review can help the scientists in related fields to take advantage of advanced TEM to their own researches.« less

  10. The interactions in the carboxyl terminus of human 4-hydroxyphenylpyruvate dioxygenase are critical to mediate the conformation of the final helix and the tail to shield the active site for catalysis.

    PubMed

    Lin, Jang-Foung; Sheih, Yung-Lin; Chang, Tsu-Chung; Chang, Ni-Yuan; Chang, Chiung-Wen; Shen, Chia-Pei; Lee, Hwei-Jen

    2013-01-01

    4-Hydroxylphenylpyruvate dioxygenase (4-HPPD) is an important enzyme for tyrosine catabolism, which catalyzes the conversion of 4-hydroxylphenylpyruvate (4-HPP) to homogentisate. In the present study, human 4-HPPD was cloned and expressed in E. coli. The kinetic parameters for 4-HPP conversion were: k cat=2.2 ± 0.1 s(-1); and K m=0.08 ± 0.02 mM. Sequence alignments show that human 4-HPPD possesses an extended C-terminus compared to other 4-HPPD enzymes. Successive truncation of the disordered tail which follows the final α-helix resulted in no changes in the K m value for 4-HPP substrate but the k cat values were significantly reduced. The results suggest that this disordered C-terminal tail plays an important role in catalysis. For inspection the effect of terminal truncation on protein structure, mutant models were built. These models suggest that the different conformation of E254, R378 and Q375 in the final helix might be the cause of the activity loss. In the structure E254 interacts with R378, the end residue in the final helix; mutation of either one of these residues causes a ca. 95% reductions in k cat values. Q375 provides bifurcate interactions to fix the tail and the final helix in position. The model of the Q375N mutant shows that a solvent accessible channel opens to the putative substrate binding site, suggesting this is responsible for the complete loss of activity. These results highlight the critical role of Q375 in orientating the tail and ensuring the conformation of the terminal α-helix to maintain the integrity of the active site for catalysis.

  11. Catalysis and biocatalysis program

    NASA Technical Reports Server (NTRS)

    Ingham, J. D.

    1993-01-01

    This final report presents a summary of research activities and accomplishments for the Catalysis and Biocatalysis Program, which was renamed the Biological and Chemical Technologies Research (BCTR) Program, currently of the Advanced Industrial Concepts Division (AICD), Office of Industrial Technologies of the Department of Energy (DOE). The Program was formerly under the Division of Energy Conversion and Utilization Technologies (ECUT) until the DOE reorganization in April, 1990. The goals of the BCTR Program are consistent with the initial ECUT goals, but represent an increased effort toward advances in chemical and biological technology transfer. In addition, the transition reflects a need for the BCTR Program to assume a greater R&D role in chemical catalysis as well as a need to position itself for a more encompassing involvement in a broader range of biological and chemical technology research. The mission of the AICD is to create a balanced Program of high risk, long-term, directed interdisciplinary research and development that will improve energy efficiency and enhance fuel flexibility in the industrial sector. Under AICD, the DOE Catalysis and Biocatalysis Program sponsors research and development in furthering industrial biotechnology applications and promotes the integrated participation of universities, industrial companies, and government research laboratories.

  12. Nanoparticle cages for enzyme catalysis in organic media.

    PubMed

    Wu, Changzhu; Bai, Shuo; Ansorge-Schumacher, Marion B; Wang, Dayang

    2011-12-15

    Encapsulation of enzymes in Pickering emulsions results in a large interfacial area of the enzyme-containing aqueous phase for biocatalysis in organic media. This immobilization technique minimizes enzyme inactivation through stabilizing immiscible liquids by particles, facilitates separation processes, and significantly increases catalytic performance of both stable and vulnerable enzymes. Thus, a broad technical applicability can be envisioned. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. THE CHELATE EFFECT IN BINDING, CATALYSIS, AND CHEMOTHERAPY. (R826653)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  14. The energy landscape of adenylate kinase during catalysis

    DOE PAGES

    Kerns, S. Jordan; Agafonov, Roman V.; Cho, Young-Jin; ...

    2015-01-12

    Kinases perform phosphoryl-transfer reactions in milliseconds; without enzymes, these reactions would take about 8,000 years under physiological conditions. Despite extensive studies, a comprehensive understanding of kinase energy landscapes, including both chemical and conformational steps, is lacking. In this paper, we scrutinize the microscopic steps in the catalytic cycle of adenylate kinase, through a combination of NMR measurements during catalysis, pre-steady-state kinetics, molecular-dynamics simulations and crystallography of active complexes. We find that the Mg 2+ cofactor activates two distinct molecular events: phosphoryl transfer (>10 5-fold) and lid opening (10 3-fold). In contrast, mutation of an essential active site arginine decelerates phosphorylmore » transfer 10 3-fold without substantially affecting lid opening. Finally, our results highlight the importance of the entire energy landscape in catalysis and suggest that adenylate kinases have evolved to activate key processes simultaneously by precise placement of a single, charged and very abundant cofactor in a preorganized active site.« less

  15. Facet‐Controlled Synthetic Strategy of Cu2O‐Based Crystals for Catalysis and Sensing

    PubMed Central

    Shang, Yang

    2015-01-01

    Shape‐dependent catalysis and sensing behaviours are primarily focused on nanocrystals enclosed by low‐index facets, especially the three basic facets ({100}, {111}, and {110}). Several novel strategies have recently exploded by tailoring the original nanocrystals to greatly improve the catalysis and sensing performances. In this Review, we firstly introduce the synthesis of a variety of Cu2O nanocrystals, including the three basic Cu2O nanocrystals (cubes, octahedra and rhombic dodecahedra, enclosed by the {100}, {111}, and {110} facets, respectively), and Cu2O nanocrystals enclosed by high‐index planes. We then discuss in detail the three main facet‐controlled synthetic strategies (deposition, etching and templating) to fabricate Cu2O‐based nanocrystals with heterogeneous, etched, or hollow structures, including a number of important concepts involved in those facet‐controlled routes, such as the selective adsorption of capping agents for protecting special facets, and the impacts of surface energy and active sites on reaction activity trends. Finally, we highlight the facet‐dependent properties of the Cu2O and Cu2O‐based nanocrystals for applications in photocatalysis, gas catalysis, organocatalysis and sensing, as well as the relationship between their structures and properties. We also summarize and comment upon future facet‐related directions. PMID:27980909

  16. Facet-Controlled Synthetic Strategy of Cu2O-Based Crystals for Catalysis and Sensing.

    PubMed

    Shang, Yang; Guo, Lin

    2015-10-01

    Shape-dependent catalysis and sensing behaviours are primarily focused on nanocrystals enclosed by low-index facets, especially the three basic facets ({100}, {111}, and {110}). Several novel strategies have recently exploded by tailoring the original nanocrystals to greatly improve the catalysis and sensing performances. In this Review, we firstly introduce the synthesis of a variety of Cu 2 O nanocrystals, including the three basic Cu 2 O nanocrystals (cubes, octahedra and rhombic dodecahedra, enclosed by the {100}, {111}, and {110} facets, respectively), and Cu 2 O nanocrystals enclosed by high-index planes. We then discuss in detail the three main facet-controlled synthetic strategies (deposition, etching and templating) to fabricate Cu 2 O-based nanocrystals with heterogeneous, etched, or hollow structures, including a number of important concepts involved in those facet-controlled routes, such as the selective adsorption of capping agents for protecting special facets, and the impacts of surface energy and active sites on reaction activity trends. Finally, we highlight the facet-dependent properties of the Cu 2 O and Cu 2 O-based nanocrystals for applications in photocatalysis, gas catalysis, organocatalysis and sensing, as well as the relationship between their structures and properties. We also summarize and comment upon future facet-related directions.

  17. United States Air Force Summer Faculty Research Program, 1988. Program Technical Report. Volume 3

    DTIC Science & Technology

    1988-12-01

    equivalents of U- bromosuccinimide. Although this dibromide ns inert to conventional hydrolysis with concentrated sulfuric acid at 11O*C, conversion to...by first dissolving in hot (II0C) sulfuric acid then pouring into ice water. The resulting precipitate ws air dried then recrystallized once more from...Catalysis Dr. Richard Carlin in Lewis Acid Molten Salts 36 A MCSCF Study of the Rearrangement Dr. Michael McKee of Nitromethane to Methyl Nitrite 37

  18. POLYCYCLIC AROMATICS FORMATION IN HSAPO-34 DURING METHANOL-TO-OLEFIN CATALYSIS: EX SITU CHARACTERIZATION AFTER CRYOGENIC GRINDING. (R826122)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  19. NOVEL RHODIUM (I) CATALYSTS FOR ECOLOGICALLY BENIGN HOMOGENEOUS CATALYSIS IN SUPERCRITICAL CARBON DIOXIDE. (R826694C640)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  20. USE OF SALT HYDRATE PAIRS TO CONTROL WATER ACTIVITY FOR ENZYME CATALYSIS IN IONIC LIQUIDS. (R828131)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  1. Systematic Functional Analysis of Active-Site Residues in l-Threonine Dehydrogenase from Thermoplasma volcanium

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

    Desjardins, Morgan; Mak, Wai Shun; O’Brien, Terrence E.

    Enzymes have been through millions of years of evolution during which their active-site microenvironments are fine-tuned. Active-site residues are commonly conserved within protein families, indicating their importance for substrate recognition and catalysis. In this work, we systematically mutated active-site residues of l-threonine dehydrogenase from Thermoplasma volcanium and characterized the mutants against a panel of substrate analogs. Our results demonstrate that only a subset of these residues plays an essential role in substrate recognition and catalysis and that the native enzyme activity can be further enhanced roughly 4.6-fold by a single point mutation. Kinetic characterization of mutants on substrate analogs showsmore » that l-threonine dehydrogenase possesses promiscuous activities toward other chemically similar compounds not previously observed. Quantum chemical calculations on the hydride-donating ability of these substrates also reveal that this enzyme did not evolve to harness the intrinsic substrate reactivity for enzyme catalysis. Our analysis provides insights into connections between the details of enzyme active-site structure and specific function. Finally, these results are directly applicable to rational enzyme design and engineering.« less

  2. Systematic Functional Analysis of Active-Site Residues in l-Threonine Dehydrogenase from Thermoplasma volcanium

    DOE PAGES

    Desjardins, Morgan; Mak, Wai Shun; O’Brien, Terrence E.; ...

    2017-07-07

    Enzymes have been through millions of years of evolution during which their active-site microenvironments are fine-tuned. Active-site residues are commonly conserved within protein families, indicating their importance for substrate recognition and catalysis. In this work, we systematically mutated active-site residues of l-threonine dehydrogenase from Thermoplasma volcanium and characterized the mutants against a panel of substrate analogs. Our results demonstrate that only a subset of these residues plays an essential role in substrate recognition and catalysis and that the native enzyme activity can be further enhanced roughly 4.6-fold by a single point mutation. Kinetic characterization of mutants on substrate analogs showsmore » that l-threonine dehydrogenase possesses promiscuous activities toward other chemically similar compounds not previously observed. Quantum chemical calculations on the hydride-donating ability of these substrates also reveal that this enzyme did not evolve to harness the intrinsic substrate reactivity for enzyme catalysis. Our analysis provides insights into connections between the details of enzyme active-site structure and specific function. Finally, these results are directly applicable to rational enzyme design and engineering.« less

  3. Proceedings of the Annual Chemical Defense Bioscience Review (5th) Held at Columbia, Maryland on 29-31 May 1985. Appendix 1

    DTIC Science & Technology

    1985-06-01

    and Meyer, H.G. Life Sciences 36: 1715-1720, 1985. 3. Van Helden, H.P.M.; van der Well, H.J.; and Wolthius, O.L. TNO Technical Report # MBL-1984-3...SYNTHESIS IN OUR LABORA- TORY BY STANDARD LITERATURE PROCEDURES OR AS A GIFT FROM PHARMA - CEUTICAL MANUFACTURERS THAT MARKET THE DRUGS, ALL OF THE COM- POUNDS...Rosenberry, T. L. Croatia Chemica Acto 1975, _7 235 Incursion of other steps then general base catalysis, such as confor-:ational changes, in rate

  4. Final Technical Report

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

    Glasser, Alan H.

    Final technical report on DE-SC0016106. This is the final technical report for a portion of the multi-institutional CEMM project. This report is centered around 3 publications and a seminar presentation, which have been submitted to E-Link.

  5. 10 CFR 52.157 - Contents of applications; technical information in final safety analysis report.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...; technical information in final safety analysis report. The application must contain a final safety analysis...) Information sufficient to demonstrate compliance with the applicable requirements regarding testing, analysis... 10 Energy 2 2013-01-01 2013-01-01 false Contents of applications; technical information in final...

  6. 10 CFR 52.157 - Contents of applications; technical information in final safety analysis report.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...; technical information in final safety analysis report. The application must contain a final safety analysis...) Information sufficient to demonstrate compliance with the applicable requirements regarding testing, analysis... 10 Energy 2 2012-01-01 2012-01-01 false Contents of applications; technical information in final...

  7. 10 CFR 52.157 - Contents of applications; technical information in final safety analysis report.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...; technical information in final safety analysis report. The application must contain a final safety analysis...) Information sufficient to demonstrate compliance with the applicable requirements regarding testing, analysis... 10 Energy 2 2014-01-01 2014-01-01 false Contents of applications; technical information in final...

  8. 10 CFR 52.157 - Contents of applications; technical information in final safety analysis report.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...; technical information in final safety analysis report. The application must contain a final safety analysis...) Information sufficient to demonstrate compliance with the applicable requirements regarding testing, analysis... 10 Energy 2 2011-01-01 2011-01-01 false Contents of applications; technical information in final...

  9. Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts

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

    Wang, Hongliang; Wang, Huamin; Kuhn, Eric

    Super Lewis acids containing the triflate anion (e.g. Hf(OTf)4, Ln(OTf)3, Al(OTf)3) and noble metal catalysts (e.g. Ru/C, Ru/Al2O3) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage via selective bonding to etheric oxygens while the noble metal catalysed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt% of the hydrocarbons produced with this catalyticmore » system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates via protonating hydroxyls and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote oxygenation reactions catalysed by super Lewis acids.« less

  10. Supramolecular control of transition metal complexes in water by a hydrophobic cavity: a bio-inspired strategy.

    PubMed

    Bistri, Olivia; Reinaud, Olivia

    2015-03-14

    Supramolecular chemistry in water is a very challenging research area. In biology, water is the universal solvent where transition metal ions play major roles in molecular recognition and catalysis. In enzymes, it participates in substrate binding and/or activation in the heart of a pocket defined by the folded protein. The association of a hydrophobic cavity with a transition metal ion is thus a very appealing strategy for controlling the metal ion properties in the very competitive water solvent. Various systems based on intrinsically water-soluble macrocyclic structures such as cyclodextrins, cucurbituryls, and metallo-cages have been reported. Others use calixarenes and resorcinarenes functionalized with hydrophilic substituents. One approach for connecting a metal complex to these cavities is to graft a ligand for metal ion binding at their edge. Early work with cyclodextrins has shown Michaelis-Menten like catalysis displaying enhanced kinetics and substrate-selectivity. Remarkable examples of regio- and stereo-selective transformation of substrates have been reported as well. Dynamic two-phase systems for transition metal catalysis have also been developed. They rely on either water-transfer of the metal complex through ligand embedment or synergistic coordination of a metal ion and substrate hosting. Another strategy consists in using metallo-cages, which provide a well-defined hydrophobic space, to stabilize metal complexes in water. When the cages can host simultaneously a substrate and a reactive metal complex, size- and regio-selective catalysis was obtained. Finally, construction of a polydentate coordination site closely interlocked with a calixarene or resorcinarene macrocycle has been shown to be a very fruitful strategy for obtaining metal complexes with remarkable hosting properties. For each of these systems, the synergism resulting from the biomimetic association of a hydrophobic cavity and a metal ion is discussed within the objective of developing new tools for either selective molecular recognition (with analytical perspectives) or performant catalysis, in water.

  11. Substrate-Assisted Catalysis in the Reaction Catalyzed by Salicylic Acid Binding Protein 2 (SABP2), a Potential Mechanism of Substrate Discrimination for Some Promiscuous Enzymes

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

    Yao, Jianzhuang; Guo, Haobo; Chaiprasongsuk, Minta

    Although one of an enzyme’s hallmarks is the high specificity for their natural substrates, substrate promiscuity has been reported more frequently. We know that promiscuous enzymes generally show different catalytic efficiencies to different substrates, but our understanding of the origin of such differences is still lacking. We report the results of quantum mechanical/molecular mechanical simulations and an experimental study of salicylic acid binding protein 2 (SABP2). SABP2 has promiscuous esterase activity toward a series of substrates but shows a high activity toward its natural substrate, methyl salicylate (MeSA). Finally, our results demonstrate that this enzyme may use substrate-assisted catalysis involvingmore » the hydroxyl group from MeSA to enhance the activity and achieve substrate discrimination.« less

  12. Substrate-Assisted Catalysis in the Reaction Catalyzed by Salicylic Acid Binding Protein 2 (SABP2), a Potential Mechanism of Substrate Discrimination for Some Promiscuous Enzymes

    DOE PAGES

    Yao, Jianzhuang; Guo, Haobo; Chaiprasongsuk, Minta; ...

    2015-08-05

    Although one of an enzyme’s hallmarks is the high specificity for their natural substrates, substrate promiscuity has been reported more frequently. We know that promiscuous enzymes generally show different catalytic efficiencies to different substrates, but our understanding of the origin of such differences is still lacking. We report the results of quantum mechanical/molecular mechanical simulations and an experimental study of salicylic acid binding protein 2 (SABP2). SABP2 has promiscuous esterase activity toward a series of substrates but shows a high activity toward its natural substrate, methyl salicylate (MeSA). Finally, our results demonstrate that this enzyme may use substrate-assisted catalysis involvingmore » the hydroxyl group from MeSA to enhance the activity and achieve substrate discrimination.« less

  13. Investigation of Chirality Selection Mechanism of Single-Walled Carbon Nanotube

    DTIC Science & Technology

    2015-07-17

    Final 3. DATES COVERED (From - To) 01-June-2014 to 31-May-2015 4. TITLE AND SUBTITLE Investigation of Chirality Selection Mechanism of...of two significant mechanistic aspects of carbon nanotube (CNT) array growth under chemical vapor deposition conditions: chirality selectivity and...affected by the morphological evolution of catalyst particles. 15. SUBJECT TERMS Carbon Nanotubes, Chirality , Processing, Catalysis

  14. Biomimetic, Self-Healing Nanocomposites for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Morse, Daniel E.

    2003-01-01

    This final report contains a summary of significant findings, and bibliographies of publications and patents resulting from the research. The findings are grouped as follows: A) Lustrin-Mimetic Self-Healing Polymer Networks; B) Nanostructure-Directing Catalysis of Synthesis of Electronically and Optoelectronically Active Metallo-oxanes and Organometallics; C) New Discovery that Molecular Stencils Control Directional Growth to Form Light-Weight Mineral Foams.

  15. Beyond relationships between homogeneous and heterogeneous catalysis

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

    Dixon, David A.; Katz, Alexander; Arslan, Ilke

    2014-08-13

    Scientists who regard catalysis as a coherent field have been striving for decades to articulate the fundamental unifying principles. But because these principles seem to be broader than chemistry, chemical engineering, and materials science combined, catalytic scientists commonly interact within the sub-domains of homogeneous, heterogeneous, and bio-catalysis, and increasingly within even narrower domains such as organocatalysis, phase-transfer catalysis, acid-base catalysis, zeolite catalysis, etc. Attempts to unify catalysis have motivated researchers to find relationships between homogeneous and heterogeneous catalysis and to mimic enzymes. These themes have inspired vibrant international meetings and workshops, and we have benefited from the idea exchanges andmore » have some thoughts about a path forward.« less

  16. Henry Taube and Coordination Chemistry

    Science.gov Websites

    Shifts Caused by Cr++ in Aqueous Solutions, DOE Technical Report, 1962 Reactions of Solvated Ions Final Report, DOE Technical Report, 1962 Isotopic Discrimination of Some Solutes in Liquid Ammonia, DOE Technical Report, 1966 Final Technical Report of Research, DOE Technical Report, 1972 Top Additional Web

  17. George A. Olah, Carbocation and Hydrocarbon Chemistry

    Science.gov Websites

    . Final Technical Report. [HF:BF{sub 2}/H{sub 2}] , DOE Technical Report, 1980 Superacid Catalyzed Coal Conversion Chemistry. 1st and 2nd Quarterly Technical Progress Reports, September 1, 1983-March 30, 1984 , DOE Technical Report, 1984 Superacid Catalyzed Coal Conversion Chemistry. Final Technical Report

  18. 77 FR 46306 - Fluxapyroxad; Pesticide Tolerances Technical Amendment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-03

    ...; Pesticide Tolerances Technical Amendment AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule; technical amendment. SUMMARY: EPA issued a final rule in the Federal Register of May 14, 2012, concerning.... Inadvertently, the terminology for the oilseed crop group and for dried plums was incorrect. This technical...

  19. Product release mechanism and the complete enzyme catalysis cycle in yeast cytosine deaminase (yCD): A computational study.

    PubMed

    Zhao, Yuan; She, Nai; Zhang, Xin; Wang, Chaojie; Mo, Yirong

    2017-08-01

    Yeast cytosine deaminase (yCD) is critical in gene-directed enzyme prodrug therapy as it catalyzes the hydrolytic deamination of cytosine. The product (uracil) release process is considered as rate-limiting in the whole enzymatic catalysis and includes the cleavage of the uracil-metal bond and the delivery of free uracil out of the reactive site. Herein extensive combined random acceleration molecular dynamics (RAMD) and molecular dynamics (MD) simulations coupled with the umbrella sampling technique have been performed to study the product transport mechanism. Five channels have been identified, and the thermodynamic and dynamic characterizations for the two most favorable channels have been determined and analyzed. The free energy barrier for the most beneficial pathway is about 13kcal/mol and mainly results from the cleavage of hydrogen bonds between the ligand uracil and surrounding residues Asn51, Glu64, and Asp155. The conjugated rings of Phe114 and Trp152 play gating and guiding roles in the product delivery via π⋯π van der Waals interactions with the product. Finally, the full cycle of the enzymatic catalysis has been determined, making the whole process computationally more precise. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Computational Glycobiology: Mechanistic Studies of Carbohydrate-Active Enzymes and Implication for Inhibitor Design.

    PubMed

    Montgomery, Andrew P; Xiao, Kela; Wang, Xingyong; Skropeta, Danielle; Yu, Haibo

    2017-01-01

    Carbohydrate-active enzymes (CAZymes) are families of essential and structurally related enzymes, which catalyze the creation, modification, and degradation of glycosidic bonds in carbohydrates to maintain essentially all kingdoms of life. CAZymes play a key role in many biological processes underpinning human health and diseases (e.g., cancer, diabetes, Alzheimer's diseases, AIDS) and have thus emerged as important drug targets in the fight against pathogenesis. The realization of the full potential of CAZymes remains a significant challenge, relying on a deeper understanding of the molecular mechanisms of catalysis. Considering numerous unsettled questions in the literature, while with a large amount of structural, kinetic, and mutagenesis data available for CAZymes, there is a pressing need and an abundant opportunity for collaborative computational and experimental investigations with the aim to unlock the secrets of CAZyme catalysis at an atomic level. In this review, we briefly survey key methodology development in computational studies of CAZyme catalysis. This is complemented by selected case studies highlighting mechanistic insights provided by computational glycobiology. Implication for inhibitor design by mimicking the transition state is also illustrated for both glycoside hydrolases and glycosyltransferases. The challenges for such studies will be noted and finally an outlook for future directions will be provided. © 2017 Elsevier Inc. All rights reserved.

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

    Ye, Rong; Hurlburt, Tyler J.; Sabyrov, Kairat

    Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nanoparticles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sumfrequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. Itmore » was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and h eterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Finally, unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis.« less

  2. Enhanced vapour sensing using silicon nanowire devices coated with Pt nanoparticle functionalized porous organic frameworks.

    PubMed

    Cao, Anping; Shan, Meixia; Paltrinieri, Laura; Evers, Wiel H; Chu, Liangyong; Poltorak, Lukasz; Klootwijk, Johan H; Seoane, Beatriz; Gascon, Jorge; Sudhölter, Ernst J R; de Smet, Louis C P M

    2018-04-19

    Recently various porous organic frameworks (POFs, crystalline or amorphous materials) have been discovered, and used for a wide range of applications, including molecular separations and catalysis. Silicon nanowires (SiNWs) have been extensively studied for diverse applications, including as transistors, solar cells, lithium ion batteries and sensors. Here we demonstrate the functionalization of SiNW surfaces with POFs and explore its effect on the electrical sensing properties of SiNW-based devices. The surface modification by POFs was easily achieved by polycondensation on amine-modified SiNWs. Platinum nanoparticles were formed in these POFs by impregnation with chloroplatinic acid followed by chemical reduction. The final hybrid system showed highly enhanced sensitivity for methanol vapour detection. We envisage that the integration of SiNWs with POF selector layers, loaded with different metal nanoparticles will open up new avenues, not only in chemical and biosensing, but also in separations and catalysis.

  3. Acid–base catalysis over perovskites: a review

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

    Polo-Garzon, Felipe; Wu, Zili

    We present that perovskite catalysts have been extensively studied for reduction–oxidation (redox) reactions; however, their acid–base catalytic properties are still under-explored. This review collects work aiming to study the acid–base catalytic properties of perovskites. Reports regarding combined acid–base/redox catalysis over perovskites lie beyond the scope of the present review. For the characterization of acid–base properties, researchers have studied the interaction of probe molecules with perovskite surfaces by means of multiple techniques that provide information about the density, strength and type of adsorption sites. The top-surface composition of perovskites, which relates to the abundance of the acid–base sites, has been studiedmore » by means of low energy ion scattering (LEIS), and, the less surface sensitive, conventional X-ray photoelectron spectroscopy (XPS). Probe reactions, with the conversion of 2-propanol as the common choice, have also been employed for characterizing the acid–base catalytic properties of perovskites. The complex nature of perovskite surfaces, which explains the still absent fundamental relations between the structure of the catalyst and reaction rates/selectivity, encounters a great challenge due to the surface reconstruction of these materials. In this review, we devote a special section to highlight recent publications that report the impact of surface reconstruction and particle shape on acid–base catalysis over perovskites. In addition, we review promising catalytic performances of perovskite catalysts for other reactions of interest. Challenges in acid–base catalysis over perovskites focus on the development of time-resolved monolayer-sensitive characterization of surfaces under operando conditions and the discernment of combined acid–base/redox reaction mechanisms. Finally, opportunities lay on tuning the acid–base characteristics of perovskites with computation-based catalytic descriptors to achieve desired selectivities and enhanced rates.« less

  4. Acid–base catalysis over perovskites: a review

    DOE PAGES

    Polo-Garzon, Felipe; Wu, Zili

    2018-01-15

    We present that perovskite catalysts have been extensively studied for reduction–oxidation (redox) reactions; however, their acid–base catalytic properties are still under-explored. This review collects work aiming to study the acid–base catalytic properties of perovskites. Reports regarding combined acid–base/redox catalysis over perovskites lie beyond the scope of the present review. For the characterization of acid–base properties, researchers have studied the interaction of probe molecules with perovskite surfaces by means of multiple techniques that provide information about the density, strength and type of adsorption sites. The top-surface composition of perovskites, which relates to the abundance of the acid–base sites, has been studiedmore » by means of low energy ion scattering (LEIS), and, the less surface sensitive, conventional X-ray photoelectron spectroscopy (XPS). Probe reactions, with the conversion of 2-propanol as the common choice, have also been employed for characterizing the acid–base catalytic properties of perovskites. The complex nature of perovskite surfaces, which explains the still absent fundamental relations between the structure of the catalyst and reaction rates/selectivity, encounters a great challenge due to the surface reconstruction of these materials. In this review, we devote a special section to highlight recent publications that report the impact of surface reconstruction and particle shape on acid–base catalysis over perovskites. In addition, we review promising catalytic performances of perovskite catalysts for other reactions of interest. Challenges in acid–base catalysis over perovskites focus on the development of time-resolved monolayer-sensitive characterization of surfaces under operando conditions and the discernment of combined acid–base/redox reaction mechanisms. Finally, opportunities lay on tuning the acid–base characteristics of perovskites with computation-based catalytic descriptors to achieve desired selectivities and enhanced rates.« less

  5. Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts

    DOE PAGES

    Wang, Hongliang; Wang, Huamin; Kuhn, Eric; ...

    2017-11-14

    Super Lewis acids containing the triflate anion [e.g., Hf(OTf) 4, Ln(OTf) 3, In(OTf) 3, Al(OTf) 3] and noble metal catalysts (e.g., Ru/C, Ru/Al2O 3) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt %more » of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote oxygenation reactions catalyzed by super Lewis acids.« less

  6. Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts

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

    Wang, Hongliang; Wang, Huamin; Kuhn, Eric

    Super Lewis acids containing the triflate anion [e.g., Hf(OTf) 4, Ln(OTf) 3, In(OTf) 3, Al(OTf) 3] and noble metal catalysts (e.g., Ru/C, Ru/Al2O 3) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt %more » of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote oxygenation reactions catalyzed by super Lewis acids.« less

  7. Characteristics of back corona discharge in a honeycomb catalyst and its application for treatment of volatile organic compounds.

    PubMed

    Feng, Fada; Zheng, Yanyan; Shen, Xinjun; Zheng, Qinzhen; Dai, Shaolong; Zhang, Xuming; Huang, Yifan; Liu, Zhen; Yan, Keping

    2015-06-02

    The main technical challenges for the treatment of volatile organic compounds (VOCs) with plasma-assisted catalysis in industrial applications are large volume plasma generation under atmospheric pressure, byproduct control, and aerosol collection. To solve these problems, a back corona discharge (BCD) configuration has been designed to evenly generate nonthermal plasma in a honeycomb catalyst. Voltage-current curves, discharge images, and emission spectra have been used to characterize the plasma. Grade particle collection results and flow field visualization in the discharge zones show not only that the particles can be collected efficiently, but also that the pressure drop of the catalyst layer is relatively low. A three-stage plasma-assisted catalysis system, comprising a dielectric barrier discharge (DBD) stage, BCD stage, and catalyst stage, was built to evaluate toluene treatment performance by BCD. The ozone analysis results indicate that BCD enhances the ozone decomposition by collecting aerosols and protecting the Ag-Mn-O catalyst downstream from aerosol contamination. The GC and FTIR results show that BCD contributes to toluene removal, especially when the specific energy input is low, and the total removal efficiency reaches almost 100%. Furthermore, this removal results in the emission of fewer byproducts.

  8. Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts.

    PubMed

    Wang, Hongliang; Wang, Huamin; Kuhn, Eric; Tucker, Melvin P; Yang, Bin

    2018-01-10

    Super Lewis acids containing the triflate anion [e.g., Hf(OTf) 4 , Ln(OTf) 3 , In(OTf) 3 , Al(OTf) 3 ] and noble metal catalysts (e.g., Ru/C, Ru/Al 2 O 3 ) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf) 4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt % of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote deoxygenation reactions catalyzed by super Lewis acids. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. 32 CFR 37.895 - How is the final performance report to be sent to the Defense Technical Information Center?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... How is the final performance report to be sent to the Defense Technical Information Center? (a... 32 National Defense 1 2014-07-01 2014-07-01 false How is the final performance report to be sent to the Defense Technical Information Center? 37.895 Section 37.895 National Defense Department of...

  10. 32 CFR 37.895 - How is the final performance report to be sent to the Defense Technical Information Center?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... How is the final performance report to be sent to the Defense Technical Information Center? (a... 32 National Defense 1 2011-07-01 2011-07-01 false How is the final performance report to be sent to the Defense Technical Information Center? 37.895 Section 37.895 National Defense Department of...

  11. 32 CFR 37.895 - How is the final performance report to be sent to the Defense Technical Information Center?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... How is the final performance report to be sent to the Defense Technical Information Center? (a... 32 National Defense 1 2013-07-01 2013-07-01 false How is the final performance report to be sent to the Defense Technical Information Center? 37.895 Section 37.895 National Defense Department of...

  12. 32 CFR 37.895 - How is the final performance report to be sent to the Defense Technical Information Center?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 1 2012-07-01 2012-07-01 false How is the final performance report to be sent to the Defense Technical Information Center? 37.895 Section 37.895 National Defense Department of... How is the final performance report to be sent to the Defense Technical Information Center? (a...

  13. Direct sp(3)C-H acroleination of N-aryl-tetrahydroisoquinolines by merging photoredox catalysis with nucleophilic catalysis.

    PubMed

    Feng, Zhu-Jia; Xuan, Jun; Xia, Xu-Dong; Ding, Wei; Guo, Wei; Chen, Jia-Rong; Zou, You-Quan; Lu, Liang-Qiu; Xiao, Wen-Jing

    2014-04-07

    Sequence catalysis merging photoredox catalysis (PC) and nucleophilic catalysis (NC) has been realized for the direct sp(3) C-H acroleination of N-aryl-tetrahydroisoquinoline (THIQ). The reaction was performed under very mild conditions and afforded products in 50-91% yields. A catalytic asymmetric variant was proved to be successful with moderate enantioselectivities (up to 83 : 17 er).

  14. 76 FR 18624 - Research, Technical Assistance and Training Programs: Notice of Final Circular

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-04

    ... to FTA Circular 6100.1D, Research and Technical Assistance Training Program: Application Instructions... DEPARTMENT OF TRANSPORTATION Federal Transit Administration Research, Technical Assistance and Training Programs: Notice of Final Circular AGENCY: Federal Transit Administration (FTA), DOT. ACTION...

  15. Uncovering the Roles of Oxygen in Cr(III) Photoredox Catalysis.

    PubMed

    Higgins, Robert F; Fatur, Steven M; Shepard, Samuel G; Stevenson, Susan M; Boston, David J; Ferreira, Eric M; Damrauer, Niels H; Rappé, Anthony K; Shores, Matthew P

    2016-04-27

    A combined experimental and theoretical investigation aims to elucidate the necessary roles of oxygen in photoredox catalysis of radical cation based Diels-Alder cycloadditions mediated by the first-row transition metal complex [Cr(Ph2phen)3](3+), where Ph2phen = bathophenanthroline. We employ a diverse array of techniques, including catalysis screening, electrochemistry, time-resolved spectroscopy, and computational analyses of reaction thermodynamics. Our key finding is that oxygen acts as a renewable energy and electron shuttle following photoexcitation of the Cr(III) catalyst. First, oxygen quenches the excited Cr(3+)* complex; this energy transfer process protects the catalyst from decomposition while preserving a synthetically useful 13 μs excited state and produces singlet oxygen. Second, singlet oxygen returns the reduced catalyst to the Cr(III) ground state, forming superoxide. Third, the superoxide species reduces the Diels-Alder cycloadduct radical cation to the final product and reforms oxygen. We compare the results of these studies with those from cycloadditions mediated by related Ru(II)-containing complexes and find that the distinct reaction pathways are likely part of a unified mechanistic framework where the photophysical and photochemical properties of the catalyst species lead to oxygen-mediated photocatalysis for the Cr-containing complex but radical chain initiation for the Ru congener. These results provide insight into how oxygen can participate as a sustainable reagent in photocatalysis.

  16. Conformational Dynamics of Thermus aquaticus DNA Polymerase I during Catalysis

    PubMed Central

    Suo, Zucai

    2014-01-01

    Despite the fact that DNA polymerases have been investigated for many years and are commonly used as tools in a number of molecular biology assays, many details of the kinetic mechanism they use to catalyze DNA synthesis remain unclear. Structural and kinetic studies have characterized a rapid, pre-catalytic open-to-close conformational change of the Finger domain during nucleotide binding for many DNA polymerases including Thermus aquaticus DNA polymerase I (Taq Pol), a thermostable enzyme commonly used for DNA amplification in PCR. However, little has been done to characterize the motions of other structural domains of Taq Pol or any other DNA polymerase during catalysis. Here, we used stopped-flow Förster resonance energy transfer (FRET) to investigate the conformational dynamics of all five structural domains of the full-length Taq Pol relative to the DNA substrate during nucleotide binding and incorporation. Our study provides evidence for a rapid conformational change step induced by dNTP binding and a subsequent global conformational transition involving all domains of Taq Pol during catalysis. Additionally, our study shows that the rate of the global transition was greatly increased with the truncated form of Taq Pol lacking the N-terminal domain. Finally, we utilized a mutant of Taq Pol containing a de novo disulfide bond to demonstrate that limiting protein conformational flexibility greatly reduced the polymerization activity of Taq Pol. PMID:24931550

  17. Dynamical network of residue–residue contacts reveals coupled allosteric effects in recognition, catalysis, and mutation

    PubMed Central

    Doshi, Urmi; Holliday, Michael J.; Eisenmesser, Elan Z.; Hamelberg, Donald

    2016-01-01

    Detailed understanding of how conformational dynamics orchestrates function in allosteric regulation of recognition and catalysis remains ambiguous. Here, we simulate CypA using multiple-microsecond-long atomistic molecular dynamics in explicit solvent and carry out NMR experiments. We analyze a large amount of time-dependent multidimensional data with a coarse-grained approach and map key dynamical features within individual macrostates by defining dynamics in terms of residue–residue contacts. The effects of substrate binding are observed to be largely sensed at a location over 15 Å from the active site, implying its importance in allostery. Using NMR experiments, we confirm that a dynamic cluster of residues in this distal region is directly coupled to the active site. Furthermore, the dynamical network of interresidue contacts is found to be coupled and temporally dispersed, ranging over 4 to 5 orders of magnitude. Finally, using network centrality measures we demonstrate the changes in the communication network, connectivity, and influence of CypA residues upon substrate binding, mutation, and during catalysis. We identify key residues that potentially act as a bottleneck in the communication flow through the distinct regions in CypA and, therefore, as targets for future mutational studies. Mapping these dynamical features and the coupling of dynamics to function has crucial ramifications in understanding allosteric regulation in enzymes and proteins, in general. PMID:27071107

  18. Minnesota Deaf-Blind Technical Assistance Project. Final Report.

    ERIC Educational Resources Information Center

    Kloos, Eric

    This final report describes activities and accomplishments of the 3-year federally supported Minnesota Deaf-Blind Technical Assistance Project. The project provided training and technical assistance, information sharing, and support services to families of children with deaf-blindness. Activities and accomplishments included: collaboration with…

  19. 75 FR 56857 - Pilot, Flight Instructor, and Pilot School Certification

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-17

    ... of part 141. Discussion of Technical Amendment Section 141.5(d) establishes the quality of training... Certification AGENCY: Federal Aviation Administration, DOT. ACTION: Final rule; technical amendment. SUMMARY: The Federal Aviation Administration (FAA) is making minor technical changes to a final rule published...

  20. Reaction mechanism of recombinant 3-oxoacyl-(acyl-carrier-protein) synthase III from Cuphea wrightii embryo, a fatty acid synthase type II condensing enzyme.

    PubMed

    Abbadi, A; Brummel, M; Schütt, B S; Slabaugh, M B; Schuch, R; Spener, F

    2000-01-01

    A unique feature of fatty acid synthase (FAS) type II of higher plants and bacteria is 3-oxoacyl-[acyl-carrier-protein (ACP)] synthase III (KAS III), which catalyses the committing condensing reaction. Working with KAS IIIs from Cuphea seeds we obtained kinetic evidence that KAS III catalysis follows a Ping-Pong mechanism and that these enzymes have substrate-binding sites for acetyl-CoA and malonyl-ACP. It was the aim of the present study to identify these binding sites and to elucidate the catalytic mechanism of recombinant Cuphea wrightii KAS III, which we expressed in Escherichia coli. We engineered mutants, which allowed us to dissect the condensing reaction into three stages, i.e. formation of acyl-enzyme, decarboxylation of malonyl-ACP, and final Claisen condensation. Incubation of recombinant enzyme with [1-(14)C]acetyl-CoA-labelled Cys(111), and the replacement of this residue by Ala and Ser resulted in loss of overall condensing activity. The Cys(111)Ser mutant, however, still was able to bind acetyl-CoA and to catalyse subsequent binding and decarboxylation of malonyl-ACP to acetyl-ACP. We replaced His(261) with Ala and Arg and found that the former lost activity, whereas the latter retained overall condensing activity, which indicated a general-base action of His(261). Double mutants Cys(111)Ser/His(261)Ala and Cys(111)Ser/His(261)Arg were not able to catalyse overall condensation, but the double mutant containing Arg induced decarboxylation of [2-(14)C]malonyl-ACP, a reaction indicating the role of His(261) in general-acid catalysis. Finally, alanine scanning revealed the involvement of Arg(150) and Arg(306) in KAS III catalysis. The results offer for the first time a detailed mechanism for a condensing reaction catalysed by a FAS type II condensing enzyme.

  1. Reaction mechanism of recombinant 3-oxoacyl-(acyl-carrier-protein) synthase III from Cuphea wrightii embryo, a fatty acid synthase type II condensing enzyme.

    PubMed Central

    Abbadi, A; Brummel, M; Schütt, B S; Slabaugh, M B; Schuch, R; Spener, F

    2000-01-01

    A unique feature of fatty acid synthase (FAS) type II of higher plants and bacteria is 3-oxoacyl-[acyl-carrier-protein (ACP)] synthase III (KAS III), which catalyses the committing condensing reaction. Working with KAS IIIs from Cuphea seeds we obtained kinetic evidence that KAS III catalysis follows a Ping-Pong mechanism and that these enzymes have substrate-binding sites for acetyl-CoA and malonyl-ACP. It was the aim of the present study to identify these binding sites and to elucidate the catalytic mechanism of recombinant Cuphea wrightii KAS III, which we expressed in Escherichia coli. We engineered mutants, which allowed us to dissect the condensing reaction into three stages, i.e. formation of acyl-enzyme, decarboxylation of malonyl-ACP, and final Claisen condensation. Incubation of recombinant enzyme with [1-(14)C]acetyl-CoA-labelled Cys(111), and the replacement of this residue by Ala and Ser resulted in loss of overall condensing activity. The Cys(111)Ser mutant, however, still was able to bind acetyl-CoA and to catalyse subsequent binding and decarboxylation of malonyl-ACP to acetyl-ACP. We replaced His(261) with Ala and Arg and found that the former lost activity, whereas the latter retained overall condensing activity, which indicated a general-base action of His(261). Double mutants Cys(111)Ser/His(261)Ala and Cys(111)Ser/His(261)Arg were not able to catalyse overall condensation, but the double mutant containing Arg induced decarboxylation of [2-(14)C]malonyl-ACP, a reaction indicating the role of His(261) in general-acid catalysis. Finally, alanine scanning revealed the involvement of Arg(150) and Arg(306) in KAS III catalysis. The results offer for the first time a detailed mechanism for a condensing reaction catalysed by a FAS type II condensing enzyme. PMID:10600651

  2. 77 FR 29247 - Federal Motor Vehicle Safety Standards; Occupant Crash Protection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-17

    ...). ACTION: Final rule; technical amendments. SUMMARY: This final rule makes technical amendments to Federal... advanced air bag requirements. As written now, the general warning label requirements contain an explicit... equipment requirements for restraint systems. This document makes technical amendments to several of the...

  3. Heterogeneous Catalysis: Understanding for Designing, and Designing for Applications.

    PubMed

    Corma, Avelino

    2016-05-17

    "… Despite the introduction of high-throughput and combinatorial methods that certainly can be useful in the process of catalysts optimization, it is recognized that the generation of fundamental knowledge at the molecular level is key for the development of new concepts and for reaching the final objective of solid catalysts by design …" Read more in the Editorial by Avelino Corma. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Millifluidics for Chemical Synthesis and Time-resolved Mechanistic Studies

    PubMed Central

    Krishna, Katla Sai; Biswas, Sanchita; Navin, Chelliah V.; Yamane, Dawit G.; Miller, Jeffrey T.; Kumar, Challa S.S.R.

    2013-01-01

    Procedures utilizing millifluidic devices for chemical synthesis and time-resolved mechanistic studies are described by taking three examples. In the first, synthesis of ultra-small copper nanoclusters is described. The second example provides their utility for investigating time resolved kinetics of chemical reactions by analyzing gold nanoparticle formation using in situ X-ray absorption spectroscopy. The final example demonstrates continuous flow catalysis of reactions inside millifluidic channel coated with nanostructured catalyst. PMID:24327099

  5. Reversible catalytic dehydrogenation of alcohols for energy storage

    DOE PAGES

    Bonitatibus, Jr., Peter J.; Chakraborty, Sumit; Doherty, Mark D.; ...

    2015-01-14

    Reversibility of a dehydrogenation/hydrogenation catalytic reaction has been an elusive target for homogeneous catalysis. In this paper, reversible acceptorless dehydrogenation of secondary alcohols and diols on iron pincer complexes and reversible oxidative dehydrogenation of primary alcohols/reduction of aldehydes with separate transfer of protons and electrons on iridium complexes are shown. Finally, this reactivity suggests a strategy for the development of reversible fuel cell electrocatalysts for partial oxidation (dehydrogenation) of hydroxyl-containing fuels.

  6. Synergistic Catalysis: A Powerful Synthetic Strategy for New Reaction Development

    PubMed Central

    Allen, Anna E.; MacMillan, David W. C.

    2012-01-01

    Synergistic catalysis is a synthetic strategy wherein both the nucleophile and the electrophile are simultaneously activated by two separate and distinct catalysts to afford a single chemical transformation. This powerful catalysis strategy leads to several benefits, specifically synergistic catalysis can (i) introduce new, previously unattainable chemical transformations, (ii) improve the efficiency of existing transformations, and (iii) create or improve catalytic enantioselectivity where stereocontrol was previously absent or challenging. This perspective aims to highlight these benefits using many of the successful examples of synergistic catalysis found in the literature. PMID:22518271

  7. Biosourced polymetallic catalysis: A surprising and efficient means to promote the Knoevenagel condensation

    NASA Astrophysics Data System (ADS)

    Deyris, Pierre-Alexandre; Bert, Valérie; Diliberto, Sébastien; Boulanger, Clotilde; Petit, Eddy; Legrand, Yves-Marie; Grison, Claude

    2018-03-01

    Zn hyperaccumulator (Arabidobsis halleri) and Zn accumulator Salix ‘Tordis’ (Salix schwerinii x S. viminalis) have shown their interest in the phytoextraction of polluted brownfields. Herein, we explore an innovative methodology based on the chemical valorization of Zn-rich biomass produced by these metallophyte plants. The approach is based on the direct use of polymetallic salts derived from plants as “Lewis acid” catalysts in organic chemistry. The formed ecocatalysts were characterized via ICP-MS, XRD, FT-IR in order to elucidate the chemical composition, structure and behavior of the formed materials. The Doebner-Knoevenagel reaction was chosen as model reaction to study their synthetic potential. Significant differences to conventional catalysts such as zinc (II) chloride are observed. They can principally be related to a mixture of unusual mineral species. DFT calculations were carried out on these salts in the context of the Gutmann theory. They allow the rationalization of experimental results. Finally, these new bio-based polymetallic catalysts illustrated the interest of this concept for green and sustainable catalysis.

  8. Mechanistic understanding of surface plasmon assisted catalysis on a single particle: cyclic redox of 4-aminothiophenol

    DOE PAGES

    Xu, Ping; Kang, Leilei; Mack, Nathan H.; ...

    2013-10-21

    We investigate surface plasmon assisted catalysis (SPAC) reactions of 4-aminothiophenol (4ATP) to and back from 4,4'-dimercaptoazobenzene (DMAB) by single particle surface enhanced Raman spectroscopy, using a self-designed gas flow cell to control the reductive/oxidative environment over the reactions. Conversion of 4ATP into DMAB is induced by energy transfer (plasmonic heating) from surface plasmon resonance to 4ATP, where O 2 (as an electron acceptor) is essential and H 2O (as a base) can accelerate the reaction. In contrast, hot electron (from surface plasmon decay) induction drives the reverse reaction of DMAB to 4ATP, where H 2O (or H 2) acts asmore » the hydrogen source. More interestingly, the cyclic redox between 4ATP and DMAB by SPAC approach has been demonstrated. Finally, this SPAC methodology presents a unique platform for studying chemical reactions that are not possible under standard synthetic conditions.« less

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

    French, Jarrod B.; Ealick, Steven E.

    The stereospecific oxidative degradation of uric acid to (S)-allantoin was recently shown to proceed via three enzymatic steps. The final conversion is a decarboxylation of the unstable intermediate 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) and is catalyzed by OHCU decarboxylase. Here we present the structures of Klebsiella pneumoniae OHCU decarboxylase in unliganded form and with bound allantoin. These structures provide evidence that ligand binding organizes the active site residues for catalysis. Modeling of the substrate and intermediates provides additional support for this hypothesis. In addition we characterize the steady state kinetics of this enzyme and report the first OHCU decarboxylase inhibitor, allopurinol, a structuralmore » isomer of hypoxanthine. This molecule is a competitive inhibitor of K. pneumoniae OHCU decarboxylase with a K{sub i} of 30 {+-} 2 {micro}m. Circular dichroism measurements confirm structural observations that this inhibitor disrupts the necessary organization of the active site. Our structural and biochemical studies also provide further insights into the mechanism of catalysis of OHCU decarboxylation.« less

  10. Homogeneous, Heterogeneous, and Enzymatic Catalysis.

    ERIC Educational Resources Information Center

    Oyama, S. Ted; Somorjai, Gabor A.

    1988-01-01

    Discusses three areas of catalysis: homegeneous, heterogeneous, and enzymatic. Explains fundamentals and economic impact of catalysis. Lists and discusses common industrial catalysts. Provides a list of 107 references. (MVL)

  11. 77 FR 30512 - Native American Career and Technical Education Program; Final Waivers and Extension of Project...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-23

    ... DEPARTMENT OF EDUCATION Native American Career and Technical Education Program; Final Waivers and... American Career and Technical Education Program Catalog of Federal Domestic Assistance (CFDA) Number: 84.101A. SUMMARY: For 60-month projects funded in fiscal year (FY) 2007 under the Native American Career...

  12. Enantioselective conjugate additions of α-amino radicals via cooperative photoredox and Lewis acid catalysis.

    PubMed

    Ruiz Espelt, Laura; McPherson, Iain S; Wiensch, Eric M; Yoon, Tehshik P

    2015-02-25

    We report the highly enantioselective addition of photogenerated α-amino radicals to Michael acceptors. This method features a dual-catalyst protocol that combines transition metal photoredox catalysis with chiral Lewis acid catalysis. The combination of these two powerful modes of catalysis provides an effective, general strategy to generate and control the reactivity of photogenerated reactive intermediates.

  13. 48 CFR 1852.235-73 - Final Scientific and Technical Reports.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Final Scientific and Technical Reports. 1852.235-73 Section 1852.235-73 Federal Acquisition Regulations System NATIONAL..., including recommendations and conclusions based on the experience and results obtained. The final report...

  14. Coosa River Storage Annex, Talladega, Alabama Environmental Investigation, Final Management and Resources Utilization Plan

    DTIC Science & Technology

    1991-02-01

    to adequately assess the health and environmental risks associated with the closure and transfer of the Annex forI other use; and 3) identification of...1990); Draft Final Technical Plan, Draft Final Sampling Design Plan and Draft Final Health and Safety Plan, USATHAMA, June 1990. 2.1.2 Draft Final...Final Technical Plan, Sampling Design Plan and Health and Safety Plan) supplied by USATHAMA. The estimate may be revised, with USATHAMA approval, as

  15. Acquisition of a Scanning Tunneling Microscope to Enhance Research and Education in Stress-Controlled Catalysis

    DTIC Science & Technology

    2015-01-14

    Feb-2014 ABSTRACT Number of Papers published in peer-reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report...educational impact of the STM/AFM. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or published that acknowledge...ARO support from the start of the project to the date of this printing. List the papers , including journal references, in the following categories

  16. A General Asymmetric Formal Synthesis of Aza-Baylis-Hillman Type Products under Bifunctional Catalysis.

    PubMed

    Frías, María; Carrasco, Ana Cristina; Fraile, Alberto; Alemán, José

    2018-03-02

    A new organocatalytic strategy for the synthesis of enantioenriched aza-Baylis-Hillman type products via a frustrated vinylogous reaction is presented. This process proceeds under mild conditions with good yields, completed Z/E selectivity and excellent enantioselectivities. Moreover, easy derivatizations of the final products led to important building blocks of organic synthesis such as 1,3-aminoalcohols and Lewis base catalysts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Enantioselective Conjugate Additions of α-Amino Radicals via Cooperative Photoredox and Lewis Acid Catalysis

    PubMed Central

    Espelt, Laura Ruiz; McPherson, Iain S.; Wiensch, Eric M.; Yoon, Tehshik P.

    2015-01-01

    We report the highly enantioselective addition of photogenerated α-amino radicals to Michael acceptors. This method features a dual-catalyst protocol that combines transition metal photoredox catalysis with chiral Lewis acid catalysis. The combination of these two powerful modes of catalysis provides an effective, general strategy to generate and control the reactivity of photogenerated reactive intermediates. PMID:25668687

  18. Seventh BES (Basic Energy Sciences) catalysis and surface chemistry research conference

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

    Not Available

    1990-03-01

    Research programs on catalysis and surface chemistry are presented. A total of fifty-seven topics are included. Areas of research include heterogeneous catalysis; catalysis in hydrogenation, desulfurization, gasification, and redox reactions; studies of surface properties and surface active sites; catalyst supports; chemical activation, deactivation; selectivity, chemical preparation; molecular structure studies; sorption and dissociation. Individual projects are processed separately for the data bases. (CBS)

  19. Catalytic synthesis of ammonia-a "never-ending story"?

    PubMed

    Schlögl, Robert

    2003-05-09

    Nitrogen atoms are essential for the function of biological molecules and thus are and important component of fertilizers and medicaments. Bonds to nitrogen also find nonbiological uses in dyes, explosives, and resins. The synthesis of all these materials requires ammonia as an activated nitrogen building block. This situation is true for natural processes and the chemical industry. Knowledge of the various techniques for the preparation of ammonia is thus of fundamental importance for chemistry. The Haber-Bosch synthesis was the first heterogeneous catalytic system employed in the chemical industry and is still in use today. Understanding the mechanism and the translation of the knowledge into technical perfection has become a fundamental criterion for scientific development in catalysis research.

  20. New Horizons in C-F Activation by Main Group Electrophiles

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

    Ozerov, Oleg V.

    2016-02-13

    This technical report describes progress on the DOE sponsored project "New Horizons in C-F Activation by Main Group Electrophiles" during the period of 09/15/2010 – 08/31/2015. The main goal of this project was to develop improved catalysts for conversion of carbon-fluorine bonds in potentially harmful compounds. The approach involved combining of a highly reactive positively charged main-group compound with a highly unreactive negatively charged species (anions) as a way to access potent catalysts for carbon-fluorine bond activation. This report details progress made in improving synthetic pathways to a variety of new anions with improved properties and analysis of their potentialmore » in catalysis.« less

  1. Platinum and palladium nano-structured catalysts for polymer electrolyte fuel cells and direct methanol fuel cells.

    PubMed

    Long, Nguyen Viet; Thi, Cao Minh; Yong, Yang; Nogami, Masayuki; Ohtaki, Michitaka

    2013-07-01

    In this review, we present the synthesis and characterization of Pt, Pd, Pt based bimetallic and multi-metallic nanoparticles with mixture, alloy and core-shell structure for nano-catalysis, energy conversion, and fuel cells. Here, Pt and Pd nanoparticles with modified nanostructures can be controllably synthesized via chemistry and physics for their uses as electro-catalysts. The cheap base metal catalysts can be studied in the relationship of crystal structure, size, morphology, shape, and composition for new catalysts with low cost. Thus, Pt based alloy and core-shell catalysts can be prepared with the thin Pt and Pt-Pd shell, which are proposed in low and high temperature proton exchange membrane fuel cells (PEMFCs), and direct methanol fuel cells (DMFCs). We also present the survey of the preparation of Pt and Pd based catalysts for the better catalytic activity, high durability, and stability. The structural transformations, quantum-size effects, and characterization of Pt and Pd based catalysts in the size ranges of 30 nm (1-30 nm) are presented in electro-catalysis. In the size range of 10 nm (1-10 nm), the pure Pt catalyst shows very large surface area for electro-catalysis. To achieve homogeneous size distribution, the shaped synthesis of the polyhedral Pt nanoparticles is presented. The new concept of shaping specific shapes and morphologies in the entire nano-scale from nano to micro, such as polyhedral, cube, octahedra, tetrahedra, bar, rod, and others of the nanoparticles is proposed, especially for noble and cheap metals. The uniform Pt based nanosystems of surface structure, internal structure, shape, and morphology in the nanosized ranges are very crucial to next fuel cells. Finally, the modifications of Pt and Pd based catalysts of alloy, core-shell, and mixture structures lead to find high catalytic activity, durability, and stability for nano-catalysis, energy conversion, fuel cells, especially the next large-scale commercialization of next PEMFCs, and DMFCs.

  2. Heterogeneous Catalysis.

    ERIC Educational Resources Information Center

    Vannice, M. A.

    1979-01-01

    Described is a graduate course in catalysis offered at Penn State University. A detailed course outline with 30 lecture topics is presented. A list of 42 references on catalysis used in place of a textbook is provided. (BT)

  3. Asymmetric Fluorination of α-Branched Cyclohexanones Enabled by a Combination of Chiral Anion Phase-Transfer Catalysis and Enamine Catalysis using Protected Amino Acids

    PubMed Central

    2015-01-01

    We report a study involving the successful merger of two separate chiral catalytic cycles: a chiral anion phase-transfer catalysis cycle to activate Selectfluor and an enamine activation cycle, using a protected amino acid as organocatalyst. We have demonstrated the viability of this approach with the direct asymmetric fluorination of α-substituted cyclohexanones to generate quaternary fluorine-containing stereocenters. With these two chiral catalytic cycles operating together in a matched sense, high enantioselectivites can be achieved, and we envisage that this dual catalysis method has the potential to be more broadly applicable, given the breadth of enamine catalysis. It also represents a rare example of chiral enamine catalysis operating successfully on α-branched ketones, substrates commonly inert to this activation mode. PMID:24684209

  4. Adenylosuccinate synthetase: recent developments.

    PubMed

    Honzatko, R B; Stayton, M M; Fromm, H J

    1999-01-01

    By exerting strategic control on purine nucleotide biosynthesis, and by engaging GTP-dependent transphosphorylation of IMP to activate loss of an oxygen atom during catalysis, adenylosuccinate synthetase remains as enzyme that justifiably fascinates students of enzyme catalysis. This review describes how the balanced application of X-ray crystallography and enzyme kinetics has advanced the comprehension of the catalytic and regulatory properties of adenylosuccinate synthetase. Detailed analysis has demonstrated the formation of 6-phosphoryl-IMP, an intermediate originally postulated over 40 years ago on the basis of oxygen-18 exchange experiments showing that position-6 oxygen of IMP becomes incorporated into phosphate. Inferences about the participation of amino acid side-chains that stabilize 6-P-IMP during catalysis have also been confirmed by site-directed mutagenesis and examination of such mutations on various kinetic parameters. Moreover, the action of certain regulatory ligands have also been viewed at atomic level resolution. For example, magnesium ion and GDP can induce conformational changes linked to the stabilization of one of two known conformations of the so-called 40s loop. Another significant finding is that two magnesium ions play fundamental roles: one binding with high affinity to the substrate GTP, and a second binding with lower affinity to the co-substrate aspartate. These structural and kinetic studies have also formed the basis for clarifying the action of various inhibitors and potentially important pharmacologic agents with this key regulatory enzyme. Finally, this review explores the current status of investigations on gene structure and gene expression in a number of organisms.

  5. Cosmic strings and baryon decay catalysis

    NASA Technical Reports Server (NTRS)

    Gregory, Ruth; Perkins, W. B.; Davis, A.-C.; Brandenberger, R. H.

    1989-01-01

    Cosmic strings, like monopoles, can catalyze proton decay. For integer charged fermions, the cross section for catalysis is not amplified, unlike in the case of monopoles. The catalysis processes are reviewed both in the free quark and skyrmion pictures and the implications for baryogenesis are discussed. A computation of the cross section for monopole catalyzed skyrmion decay is presented using classical physics. Also discussed are some effects which can screen catalysis processes.

  6. Catalysis by Metallic Nanoparticles in Solution: Thermosensitive Microgels as Nanoreactors

    NASA Astrophysics Data System (ADS)

    Roa, Rafael; Angioletti-Uberti, Stefano; Lu, Yan; Dzubiella, Joachim; Piazza, Francesco; Ballauff, Matthias

    2018-05-01

    Metallic nanoparticles have been used as catalysts for various reactions, and the huge literature on the subject is hard to overlook. In many applications, the nanoparticles must be affixed to a colloidal carrier for easy handling during catalysis. These "passive carriers" (e.g. dendrimers) serve for a controlled synthesis of the nanoparticles and prevent coagulation during catalysis. Recently, hybrids from nanoparticles and polymers have been developed that allow us to change the catalytic activity of the nanoparticles by external triggers. In particular, single nanoparticles embedded in a thermosensitive network made from poly(N-isopropylacrylamide) (PNIPAM) have become the most-studied examples of such hybrids: immersed in cold water, the PNIPAM network is hydrophilic and fully swollen. In this state, hydrophilic substrates can diffuse easily through the network, and react at the surface of the nanoparticles. Above the volume transition located at 32°C, the network becomes hydrophobic and shrinks. Now hydrophobic substrates will preferably diffuse through the network and react with other substrates in the reaction catalyzed by the enclosed nanoparticle. Such "active carriers", may thus be viewed as true nanoreactors that open new ways for the use of nanoparticles in catalysis. In this review, we give a survey on recent work done on these hybrids and their application in catalysis. The aim of this review is threefold: we first review hybrid systems composed of nanoparticles and thermosensitive networks and compare these "active carriers" to other colloidal and polymeric carriers (e.g. dendrimers). In a second step we discuss the model reactions used to obtain precise kinetic data on the catalytic activity of nanoparticles in various carriers and environments. These kinetic data allow us to present a fully quantitative comparison of different nanoreactors. In a final section we shall present the salient points of recent efforts in the theoretical modeling of these nanoreactors. By accounting for the presence of a free-energy landscape for the reactants' diffusive approach towards the catalytic nanoparticle, arising from solvent-reactant and polymeric shell-reactant interactions, these models are capable of explaining the emergence of all the important features observed so far in studies of nanoreactors. The present survey also suggests that such models may be used for the design of future carrier systems adapted to a given reaction and solvent.

  7. USD Catalysis Group for Alternative Energy - Final report

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

    Hoefelmeyer, James

    2014-10-03

    I. Project Summary Catalytic processes are a major technological underpinning of modern society, and are essential to the energy sector in the processing of chemical fuels from natural resources, fine chemicals synthesis, and energy conversion. Advances in catalyst technology are enormously valuable since these lead to reduced chemical waste, reduced energy loss, and reduced costs. New energy technologies, which are critical to future economic growth, are also heavily reliant on catalysts, including fuel cells and photo-electrochemical cells. Currently, the state of South Dakota is underdeveloped in terms of research infrastructure related to catalysis. If South Dakota intends to participate inmore » significant economic growth opportunities that result from advances in catalyst technology, then this area of research needs to be made a high priority for investment. To this end, a focused research effort is proposed in which investigators from The University of South Dakota (USD) and The South Dakota School of Mines and Technology (SDSMT) will contribute to form the South Dakota Catalysis Group (SDCG). The multidisciplinary team of the (SDCG) include: (USD) Dan Engebretson, James Hoefelmeyer, Ranjit Koodali, and Grigoriy Sereda; (SDSMT) Phil Scott Ahrenkiel, Hao Fong, Jan Puszynski, Rajesh Shende, and Jacek Swiatkiewicz. The group is well suited to engage in a collaborative project due to the resources available within the existing programs. Activities within the SDCG will be monitored through an external committee consisting of three distinguished professors in chemistry. The committee will provide expert advice and recommendations to the SDCG. Advisory meetings in which committee members interact with South Dakota investigators will be accompanied by individual oral and poster presentations in a materials and catalysis symposium. The symposium will attract prominent scientists, and will enhance the visibility of research in the state of South Dakota. The SDCG requests funding through the Department of Energy (DoE) to establish this multidisciplinary research cluster in the area of catalysis. This long-term approach includes synthesis, characterization, catalyst evaluation, modeling, and scale-up. The project includes plans to acquire instrumentation critical to enabling competitive research. These acquisitions will complement existing resources in the state. The effect of implementation of the proposed efforts will be to significantly enhance state infrastructure in personnel and equipment, and lead to a nationally and internationally recognized research center.« less

  8. Support for U.S. Participants at the 15th International Congress on Catalysis

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

    Wachs, Israel E.

    2013-08-05

    The grant was used to partially assist the travel expenses of U.S. academic scientists to attend the 15th International Congress on Catalysis. The conference was held in Munich, Germany from July 1-6, 2012. The importance of the International Congress was to bring together the international community of faculty members who participate in catalysis research, and to share information that would lead to further developments and directions in the field of study. Graduate students and Post Docs were invited to apply for travel assistance based on criteria established by the North American Catalysis Society (NACS) and the local Catalysis Clubs.

  9. Catalysis of Photochemical Reactions.

    ERIC Educational Resources Information Center

    Albini, A.

    1986-01-01

    Offers a classification system of catalytic effects in photochemical reactions, contrasting characteristic properties of photochemical and thermal reactions. Discusses catalysis and sensitization, examples of catalyzed reactions of excepted states, complexing ground state substrates, and catalysis of primary photoproducts. (JM)

  10. High-efficiency and mechano-/photo- bi-catalysis of piezoelectric-ZnO@ photoelectric-TiO2 core-shell nanofibers for dye decomposition.

    PubMed

    You, Huilin; Wu, Zheng; Jia, Yanmin; Xu, Xiaoli; Xia, Yuntao; Han, Zichen; Wang, Yu

    2017-09-01

    A mechano-/photo- bi-catalyst of piezoelectric-ZnO@photoelectric-TiO 2 core-shell nanofibers was hydrothermally synthesized for Methyl Orange (10 mg L -1 ) decomposition. The mechano-/photo- bi-catalysis in ZnO@TiO 2 is superior to mechano- or photo-catalysis in decomposing Methyl Orange, which is mainly attributed to the synergy effect of the piezoelectric-ZnO core's mechano-catalysis and the thin photoelectric TiO 2 shell's photo-catalysis. The heterostructure of the piezoelectric-ZnO@photoelectric-TiO 2 core-shell interface, being helpful to reduce electron-hole pair recombination and to separate the piezoelectrically-/photoelectric ally- induced electrons and holes, may also make a great contribution to the enhanced catalysis performance. The mechano-/photo-bi-catalysis in ZnO@TiO 2 core-shell nanofibers possesses the advantages of high efficiency, non-toxicity and tractability and is potential in utilizing mechanical/solar energy to deal with dye wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Moving to Sustainable Metals. Multifunctional Ligands in Catalytic, Outer Sphere C-H, N-H and O-H Activation

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

    Crabtree, Robert

    2015-03-03

    Much of our work during this grant period has emphasized green chemistry and sustainability. For example, we were able to convert glycerine, a waste byproduct of biodiesel production, into lactic acid, a compound with numerous applications, notably in the food and cosmetics industry, as well as being a source material for a biodegradable plastic. This work required a catalyst, that ceases to work after a certain lapse of time. We were able to identify the way in which this deactivation occurs by identifying some of the metal catalyst deactivation products. These proved to be multimetallic clusters containing up to sixmore » metals and up to 14 hydrogen atoms. Both the catalytic reaction itself and the deactivation structures are novel and unexpected. We have previously proposed that nitrogen heterocycles could be good energy carriers in a low CO 2 future world. In another part of our study, we found catalysts for introduction of hydrogen, an energy carrier that is hard to store, into nitrogen heterocycles. The mechanism of this process proved to be unusual in that the catalyst transfers the H 2 to the heterocycle in the form of H + and H -, first transferring the H + and only then the H -. In a third area of study, some of our compounds, originally prepared for DOE catalysis purposes, also proved useful in hydrocarbon oxidation and in water oxidation. The latter is important in solar-to-fuel work, because, by analogy with natural photosynthesis, the goal of the Yale Solar Group of four PIs is to convert sunlight to hydrogen and oxygen, which requires water splitting catalysts. The catalysts that proved useful mediate the latter reaction: water oxidation to oxygen. In a more technical study, we developed methods for distinguishing the case where catalysis is mediated by a soluble catalyst from cases where catalysis arises from a deposit of finely divided solid. One particular application involved electrocatalysis, where catalysis is driven by application of a voltage to electrodes dipped in the reactant mixture. We measured the mass increase of an electrode as material is deposited, and were able to see how this process is affected by the voltage supplied to the electrode. Our work continues to be well cited and we often receive requests for information or samples from fellow researchers.« less

  12. 77 FR 50589 - Agreements and Memoranda of Understanding Between the Food and Drug Administration and Other...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ...: Final rule. SUMMARY: This final rule makes technical changes that will update a requirement that many of the written agreements and memoranda of understanding (MOUs) between the Food and Drug Administration.... This final rule, accordingly, eliminates it. We are making these technical changes to conserve Agency...

  13. 77 FR 30514 - Native Hawaiian Career and Technical Education Program; Final Waiver and Extension of Project Period

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-23

    ... DEPARTMENT OF EDUCATION Native Hawaiian Career and Technical Education Program; Final Waiver and.... ACTION: Notice. Overview Information Final Waiver and Extension of Project Period for the Native Hawaiian.... SUMMARY: For 36-month projects funded in fiscal year (FY) 2009 under the Native Hawaiian Career and...

  14. Computational Design of Clusters for Catalysis

    NASA Astrophysics Data System (ADS)

    Jimenez-Izal, Elisa; Alexandrova, Anastassia N.

    2018-04-01

    When small clusters are studied in chemical physics or physical chemistry, one perhaps thinks of the fundamental aspects of cluster electronic structure, or precision spectroscopy in ultracold molecular beams. However, small clusters are also of interest in catalysis, where the cold ground state or an isolated cluster may not even be the right starting point. Instead, the big question is: What happens to cluster-based catalysts under real conditions of catalysis, such as high temperature and coverage with reagents? Myriads of metastable cluster states become accessible, the entire system is dynamic, and catalysis may be driven by rare sites present only under those conditions. Activity, selectivity, and stability are highly dependent on size, composition, shape, support, and environment. To probe and master cluster catalysis, sophisticated tools are being developed for precision synthesis, operando measurements, and multiscale modeling. This review intends to tell the messy story of clusters in catalysis.

  15. Synthesis of high surface area nanomaterials and their application in catalysis

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

    Chaudhary, Umesh

    2016-05-01

    The dissertation is organized in 4 chapters. Chapter 1 highlights the motivations behind our research along with a general introduction on ceria and carbon catalysts. Chapter 2 reports the investigations on Copper-Ceria catalysts for the selective hydrogenation of fatty acids into fatty alcohols. Chapter 3 discusses the development of nitrogen containing mesoporous carbon. The chapter also reports the catalytic investigations for aldol condensation and nitrobenzene hydrogenation reactions. Finally, Chapter 4 is a general conclusion summarizing this dissertation.

  16. Kinetics and Catalysis Demonstrations.

    ERIC Educational Resources Information Center

    Falconer, John L.; Britten, Jerald A.

    1984-01-01

    Eleven videotaped kinetics and catalysis demonstrations are described. Demonstrations include the clock reaction, oscillating reaction, hydrogen oxidation in air, hydrogen-oxygen explosion, acid-base properties of solids, high- and low-temperature zeolite reactivity, copper catalysis of ammonia oxidation and sodium peroxide decomposition, ammonia…

  17. 2005 v4.3 Technical Support Document

    EPA Pesticide Factsheets

    Emissions Modeling for the Final Mercury and Air Toxics Standards Technical Support Document describes how updated 2005 NEI, version 2 emissions were processed for air quality modeling in support of the final Mercury and Air Toxics Standards (MATS).

  18. Virtual special issue on catalysis at the U.S. Department of Energy's National Laboratories

    DOE PAGES

    Pruski, Marek; Sadow, Aaron D.; Slowing, Igor I.; ...

    2016-04-21

    Here the catalysis research at the U.S. Department of Energy's (DOE's) National Laboratories covers a wide range of research topics in heterogeneous catalysis, homogeneous/molecular catalysis, biocatalysis, electrocatalysis, and surface science. Since much of the work at National Laboratories is funded by DOE, the research is largely focused on addressing DOE's mission to ensure America's security and prosperity by addressing its energy, environmental, and nuclear challenges through transformative science and technology solutions.

  19. Heterogeneous Molecular Catalysis of Electrochemical Reactions: Volcano Plots and Catalytic Tafel Plots.

    PubMed

    Costentin, Cyrille; Savéant, Jean-Michel

    2017-06-14

    We analyze here, in the framework of heterogeneous molecular catalysis, the reasons for the occurrence or nonoccurrence of volcanoes upon plotting the kinetics of the catalytic reaction versus the stabilization free energy of the primary intermediate of the catalytic process. As in the case of homogeneous molecular catalysis or catalysis by surface-active metallic sites, a strong motivation of such studies relates to modern energy challenges, particularly those involving small molecules, such as water, hydrogen, oxygen, proton, and carbon dioxide. This motivation is particularly pertinent for what concerns heterogeneous molecular catalysis, since it is commonly preferred to homogeneous molecular catalysis by the same molecules if only for chemical separation purposes and electrolytic cell architecture. As with the two other catalysis modes, the main drawback of the volcano plot approach is the basic assumption that the kinetic responses depend on a single descriptor, viz., the stabilization free energy of the primary intermediate. More comprehensive approaches, investigating the responses to the maximal number of experimental factors, and conveniently expressed as catalytic Tafel plots, should clearly be preferred. This is more so in the case of heterogeneous molecular catalysis in that additional transport factors in the supporting film may additionally affect the current-potential responses. This is attested by the noteworthy presence of maxima in catalytic Tafel plots as well as their dependence upon the cyclic voltammetric scan rate.

  20. The Center for Space Telemetering and Telecommunications Systems

    NASA Technical Reports Server (NTRS)

    Horan, S.; DeLeon, P.; Borah, D.; Lyman, R.

    2003-01-01

    This report comprises the final technical report for the research grant 'Center for Space Telemetering and Telecommunications Systems' sponsored by the National Aeronautics and Space Administration's Goddard Space Flight Center. The grant activities are broken down into the following technology areas: (1) Space Protocol Testing; (2) Autonomous Reconfiguration of Ground Station Receivers; (3) Satellite Cluster Communications; and (4) Bandwidth Efficient Modulation. The grant activity produced a number of technical reports and papers that were communicated to NASA as they were generated. This final report contains the final summary papers or final technical report conclusions for each of the project areas. Additionally, the grant supported students who made progress towards their degrees while working on the research.

  1. Promotion of the Equal Access of Girls and Women to Technical and Vocational Education. Studies on Technical and Vocational Education 7.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    This monograph includes the final report of the International Expert Meeting on the Promotion of Equal Access of Girls and Women to Technical and Vocational Education (TVE) held in Seoul, Republic of Korea, and country discussion papers. The final report is composed of an introduction that proposes that many Member States require special measures…

  2. Air Quality Modeling Technical Support Document for the Final Cross State Air Pollution Rule Update

    EPA Pesticide Factsheets

    In this technical support document (TSD) we describe the air quality modeling performed to support the final Cross State Air Pollution Rule for the 2008 ozone National Ambient Air Quality Standards (NAAQS).

  3. 7 CFR 614.7 - Preliminary technical determinations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Preliminary technical determinations. 614.7 Section... Preliminary technical determinations. (a) A preliminary technical determination becomes final 30 days after... purpose of gathering additional information and discussing the facts relating to the preliminary technical...

  4. Chemical Synthesis of Complex Molecules Using Nanoparticle Catalysis

    PubMed Central

    Cong, Huan; Porco, John A.

    2011-01-01

    Nanoparticle catalysis has emerged as an active topic in organic synthesis. Of particular interest is the development of enabling methodologies to efficiently assemble complex molecules using nanoparticle catalysis. This Viewpoint highlights recent developments and discusses future perspectives in this emerging field. PMID:22347681

  5. Daniel Dupuis | NREL

    Science.gov Websites

    Dupuis Dan Dupuis Advanced Catalysis Engineer Daniel.Dupuis@nrel.gov | 303-384-7685 Orcid ID http ://orcid.org/0000-0002-1142-9713 Research Interests Advanced fuel synthesis and catalysis Catalyst synthesis Community College, 2012 Professional Experience Advanced Catalysis Engineer, National Renewable Energy

  6. Catalysis and prebiotic RNA synthesis

    NASA Technical Reports Server (NTRS)

    Ferris, James P.

    1993-01-01

    The essential role of catalysis for the origins of life is discussed. The status of the prebiotic synthesis of 2',5'- and 3'5'-linked oligomers of RNA is reviewed. Examples of the role of metal ion and mineral catalysis in RNA oligomer formation are discussed.

  7. Sequential rhodium/palladium catalysis: enantioselective formation of dihydroquinolinones in the presence of achiral and chiral ligands.

    PubMed

    Zhang, Lei; Qureshi, Zafar; Sonaglia, Lorenzo; Lautens, Mark

    2014-12-08

    Compatible combinations of achiral and chiral ligands can be used in rhodium/palladium catalysis to achieve highly enantioselective domino reactions. The difference in rates of catalysis and minimal effects of ligand interference confer control in the domino sequence. The "all-in-one" 1,4-conjugate arylation and C-N cross-coupling through sequential Rh/Pd catalysis provides access to enantioenriched dihydroquinolinone building blocks. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Enantio-Relay Catalysis Constructs Chiral Biaryl Alcohols over Cascade Suzuki Cross-Coupling-Asymmetric Transfer Hydrogenation

    NASA Astrophysics Data System (ADS)

    Zhang, Dacheng; Gao, Xiaoshuang; Cheng, Tanyu; Liu, Guohua

    2014-05-01

    The construction of chiral biaryl alcohols using enantio-relay catalysis is a particularly attractive synthetic method in organic synthesis. However, overcoming the intrinsic incompatibility of distinct organometallic complexes and the reaction conditions used are significant challenges in asymmetric catalysis. To overcome these barriers, we have taken advantage of an enantio-relay catalysis strategy and a combined dual-immobilization approach. We report the use of an imidazolium-based organopalladium-functionalized organic-inorganic hybrid silica and ethylene-coated chiral organoruthenium-functionalized magnetic nanoparticles to catalyze a cascade Suzuki cross-coupling-asymmetric transfer hydrogenation reaction to prepare chiral biaryl alcohols in a two-step, one-pot process. As expected, the site-isolated active species, salient imidazolium phase-transfer character and high ethylene-coated hydrophobicity can synergistically boost the catalytic performance. Furthermore, enantio-relay catalysis has the potential to efficiently prepare a variety of chiral biaryl alcohols. Our synthetic strategy is a general method that shows the potential of developing enantio-relay catalysis towards environmentally benign and sustainable organic synthesis.

  9. Biosourced Polymetallic Catalysis: A Surprising and Efficient Means to Promote the Knoevenagel Condensation

    PubMed Central

    Deyris, Pierre-Alexandre; Bert, Valérie; Diliberto, Sébastien; Boulanger, Clotilde; Petit, Eddy; Legrand, Yves-Marie; Grison, Claude

    2018-01-01

    Zn hyperaccumulator (Arabidobsis halleri) and Zn accumulator Salix “Tordis” (Salix schwerinii × Salix viminalis) have shown their interest in the phytoextraction of polluted brownfields. Herein, we explore a novel methodology based on the chemical valorization of Zn-rich biomass produced by these metallophyte plants. The approach is based on the use of polymetallic salts derived from plants as bio-based catalysts in organic chemistry. The formed ecocatalysts were characterized via ICP-MS, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) in order to precise the chemical composition, structure, and behavior of the formed materials. The Doebner-Knoevenagel reaction was chosen as model reaction to study their synthetic potential. Significant differences to usual catalysts such as zinc (II) chloride are observed. They can principally be related to a mixture of unusual mineral species. DFT calculations were carried out on these salts in the context of the Gutmann theory. They allow the rationalization of experimental results. Finally, these new bio-based polymetallic catalysts illustrated the interest of this concept for green and sustainable catalysis. PMID:29637065

  10. Biosourced Polymetallic Catalysis: A Surprising and Efficient Means to Promote the Knoevenagel Condensation.

    PubMed

    Deyris, Pierre-Alexandre; Bert, Valérie; Diliberto, Sébastien; Boulanger, Clotilde; Petit, Eddy; Legrand, Yves-Marie; Grison, Claude

    2018-01-01

    Zn hyperaccumulator ( Arabidobsis halleri ) and Zn accumulator Salix "Tordis" ( Salix schwerinii × Salix viminalis ) have shown their interest in the phytoextraction of polluted brownfields. Herein, we explore a novel methodology based on the chemical valorization of Zn-rich biomass produced by these metallophyte plants. The approach is based on the use of polymetallic salts derived from plants as bio-based catalysts in organic chemistry. The formed ecocatalysts were characterized via ICP-MS, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) in order to precise the chemical composition, structure, and behavior of the formed materials. The Doebner-Knoevenagel reaction was chosen as model reaction to study their synthetic potential. Significant differences to usual catalysts such as zinc (II) chloride are observed. They can principally be related to a mixture of unusual mineral species. DFT calculations were carried out on these salts in the context of the Gutmann theory. They allow the rationalization of experimental results. Finally, these new bio-based polymetallic catalysts illustrated the interest of this concept for green and sustainable catalysis.

  11. Development of Catalysts and Ligands for Enantioselective Gold Catalysis

    PubMed Central

    Wang, Yi-Ming; Lackner, Aaron D.; Toste, F. Dean

    2014-01-01

    CONSPECTUS The use of Au(I) complexes for the catalytic activation of C-C π-bonds has been the subject of intense investigation in the last decade or so. The facile formation of carbon-carbon and carbon-heteroatom bonds facilitated by gold naturally led to efforts to render these transformations enantioselective. Early examples of enantioselective gold-catalyzed transformations have focused on bis(phosphinegold) complexes derived from axially chiral scaffolds. Although these complexes were highly successful in some reactions like cyclopropanation, careful choice of the weakly coordinating ligand (or counterion) was needed to obtain high levels of enantioselectivity for the case of allene hydroamination. These counterion effects led us to use the anion itself as a source of chirality, which was successful in the case of allene hydroalkoxylation. In order to expand the scope of reactions amenable to enantioselective gold catalysis to cycloadditions and other carbocyclization processes, a new class of mononuclear phosphite and phosphoramidite ligands was developed to supplement the previously widely utilized phosphines. Finally carbene ligands, in particular, the acyclic diaminocarbenes, have also been successfully applied to enantioselective transformations. PMID:24228794

  12. Biotransformation of menadione to its prenylated derivative MK-3 using recombinant Pichia pastoris.

    PubMed

    Li, Zhemin; Zhao, Genhai; Liu, Hui; Guo, Yugang; Wu, Hefang; Sun, Xiaowen; Wu, Xihua; Zheng, Zhiming

    2017-07-01

    Prenylated quinones, especially menaquinones, have significant physiological activities, but are arduous to synthesize efficiently. Due to the relaxed aromatic substrate specificity and prenylation regiospecificity at the ortho- site of the phenolic hydroxyl group, the aromatic prenyltransferase NovQ from Streptomyces may be useful in menaquinone synthesis from menadione. In this study, NovQ was overexpressed in Pichia pastoris. After fermentation optimization, NovQ production increased by 1617%. Then the different effects of metal ions, detergents and pH on the activity of purified NovQ were investigated to optimize the prenylation reaction. Finally, purified NovQ and cells containing NovQ were used for menadione prenylation in vitro and in vivo, respectively. Menaquinone-1 (MK-1) was detected as the only product in vitro with γ,γ-dimethylallyl pyrophosphate and menadione hydroquinol substrates. MK-3 at a concentration of 90.53 mg/L was detected as the major product of whole cell catalysis with 3-methyl-2-buten-1-ol and menadione hydroquinol substrates. This study realized whole cell catalysis converting menadione to menaquinones.

  13. Programs of Study as a State Policy Mandate: A Longitudinal Study of the South Carolina Personal Pathways to Success Initiative. Final Technical Report: Major Findings and Implications

    ERIC Educational Resources Information Center

    Hammond, Cathy; Drew, Sam F.; Withington, Cairen; Griffith, Cathy; Swiger, Caroline M.; Mobley, Catherine; Sharp, Julia L.; Stringfield, Samuel C.; Stipanovic, Natalie; Daugherty, Lindsay

    2013-01-01

    This is the final technical report from the National Research Center for Career and Technical Education's (NRCCTE's) five-year longitudinal study of South Carolina's Personal Pathway to Success initiative, which was authorized by the state's Education and Economic Development Act (EEDA) in 2005. NRCCTE-affiliated researchers at the National…

  14. Direct Final Rule: Nonroad Diesel Technical Amendments and Tier 3 Technical Relief Provision

    EPA Pesticide Factsheets

    Rule making certain technical corrections to the rules establishing emission standards for nonroad diesel engines and amending those rules to provide manufacturers with a production technical relief provision for Tier 3 equipment.

  15. Enzyme catalysis-electrophoresis titration for multiplex enzymatic assay via moving reaction boundary chip.

    PubMed

    Zhong, Ran; Xie, Haiyang; Kong, Fanzhi; Zhang, Qiang; Jahan, Sharmin; Xiao, Hua; Fan, Liuyin; Cao, Chengxi

    2016-09-21

    In this work, we developed the concept of enzyme catalysis-electrophoresis titration (EC-ET) under ideal conditions, the theory of EC-ET for multiplex enzymatic assay (MEA), and a related method based on a moving reaction boundary (MRB) chip with a collateral channel and cell phone imaging. As a proof of principle, the model enzymes horseradish peroxidase (HRP), laccase and myeloperoxidase (MPO) were chosen for the tests of the EC-ET model. The experiments revealed that the EC-ET model could be achieved via coupling EC with ET within a MRB chip; particularly the MEA analyses of catalysis rate, maximum rate, activity, Km and Kcat could be conducted via a single run of the EC-ET chip, systemically demonstrating the validity of the EC-ET theory. Moreover, the developed method had these merits: (i) two orders of magnitude higher sensitivity than a fluorescence microplate reader, (ii) simplicity and low cost, and (iii) fairly rapid (30 min incubation, 20 s imaging) analysis, fair stability (<5.0% RSD) and accuracy, thus validating the EC-ET method. Finally, the developed EC-ET method was used for the clinical assay of MPO activity in blood samples; the values of MPO activity detected via the EC-ET chip were in agreement with those obtained by a traditional fluorescence microplate reader, indicating the applicability of the EC-ET method. The work opens a window for the development of enzymatic research, enzyme assay, immunoassay, and point-of-care testing as well as titration, one of the oldest methods of analysis, based on a simple chip.

  16. At the Dawn of the 21st Century: Is Dynamics the Missing Link for Understanding Enzyme Catalysis?

    PubMed Central

    Kamerlin, Shina C. L.; Warshel, Arieh

    2009-01-01

    Enzymes play a key role in almost all biological processes, accelerating a variety of metabolic reactions as well as controlling energy transduction, transcription and translation of genetic information, and signaling. They possess the remarkable capacity to accelerate reactions by many orders of magnitude compared to their uncatalyzed counterparts, making feasible crucial processes that would otherwise not occur on biologically relevant timescales. Thus, there is broad interest in understanding the catalytic power of enzymes on a molecular level. Several proposals have been put forward to try to explain this phenomenon, and one that has rapidly gained momentum in recent years is the idea that enzyme dynamics somehow contributes to catalysis. This review examines the dynamical proposal in a critical way considering basically all reasonable definitions, including (but not limited to) such proposed effects as “coupling between conformational and chemical motions”, “landscape searches” and “entropy funnels”. It is shown that none of these proposed effects have been experimentally demonstrated to contribute to catalysis, nor are they supported by consistent theoretical studies. On the other hand, it is clarified that careful simulation studies have excluded most (if not all) dynamical proposals. This review places significant emphasis on clarifying the role of logical definitions of different catalytic proposals, and on the need for a clear formulation in terms of the assumed potential surface and reaction coordinate. Finally, it is pointed out that electrostatic preorganization actually accounts for the observed catalytic effects of enzymes, through the corresponding changes in the activation free energies. PMID:20099310

  17. Surface chemistry of Au/TiO2: Thermally and photolytically activated reactions

    NASA Astrophysics Data System (ADS)

    Panayotov, Dimitar A.; Morris, John R.

    2016-03-01

    The fascinating particle size dependence to the physical, photophysical, and chemical properties of gold has motivated thousands of studies focused on exploring the ability of supported gold nanoparticles to catalyze chemical transformations. In particular, titanium dioxide-supported gold (Au/TiO2) nanoparticles may provide the right combination of electronic structure, structural dynamics, and stability to affect catalysis in important practical applications from environmental remediation to selective hydrogenation to carbon monoxide oxidation. Harnessing the full potential of Au/TiO2 will require a detailed atomic-scale understanding of the thermal and photolytic processes that accompany chemical conversion. This review describes some of the unique properties exhibited by particulate gold before delving into how those properties affect chemistry on titania supports. Particular attention is given first to thermally driven reactions on single crystal system. This review then addresses nanoparticulate samples in an effort begin to bridge the so-called materials gap. Building on the foundation provided by the large body of work in the field of thermal catalysis, the review describes new research into light-driven catalysis on Au/TiO2. Importantly, the reader should bear in mind throughout this review that thermal chemistry and thermal effects typically accompany photochemistry. Distinguishing between thermally-driven stages of a reaction and photo-induced steps remains a significant challenge, but one that experimentalists and theorists are beginning to decipher with new approaches. Finally, a summary of several state-of-the-art studies describes how they are illuminating new frontiers in the quest to exploit Au/TiO2 as an efficient catalyst and low-energy photocatalyst.

  18. Asymmetric Aldol Additions: A Guided-Inquiry Laboratory Activity on Catalysis

    ERIC Educational Resources Information Center

    King, Jorge H. Torres; Wang, Hong; Yezierski, Ellen J.

    2018-01-01

    Despite the importance of asymmetric catalysis in both the pharmaceutical and commodity chemicals industries, asymmetric catalysis is under-represented in undergraduate chemistry laboratory curricula. A novel guided-inquiry experiment based on the asymmetric aldol addition was developed. Students conduct lab work to compare the effectiveness of…

  19. Advances in Nucleophilic Phosphine Catalysis of Alkenes, Allenes, Alkynes, and MBHADs

    PubMed Central

    Fan, Yi Chiao

    2014-01-01

    In nucleophilic phosphine catalysis, tertiary phosphines undergo conjugate additions to activated carbon–carbon multiple bonds to form β-phosphonium enolates, β-phosphonium dienolates, β-phosphonium enoates, and vinyl phosphonium ylides as intermediates. When these reactive zwitterionic species react with nucleophiles and electrophiles, they may generate carbo- and heterocycles with multifarious molecular architectures. This Article describes the reactivities of these phosphonium zwitterions, the applications of phosphine catalysis in the syntheses of biologically active compounds and natural products, and recent developments in the enantioselective phosphine catalysis. PMID:24196409

  20. Magnetic catalysis and inverse magnetic catalysis in (2 +1 )-dimensional gauge theories from holographic models

    NASA Astrophysics Data System (ADS)

    Rodrigues, Diego M.; Capossoli, Eduardo Folco; Boschi-Filho, Henrique

    2018-06-01

    We study the deconfinement phase transition in (2 +1 )-dimensional holographic S U (N ) gauge theories in the presence of an external magnetic field from the holographic hard and soft wall models. We obtain exact solutions for the critical temperature of the deconfinement transition for any range of magnetic field. As a consequence, we find a critical magnetic field (Bc), in which the critical temperature (Tc) vanishes; for B Bc we have a magnetic catalysis.

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

    Pruski, Marek; Sadow, Aaron D.; Slowing, Igor I.

    Catalysis research at the U.S. Department of Energy's (DOE's) National Laboratories covers a wide range of research topics in heterogeneous catalysis, homogeneous/molecular catalysis, biocatalysis, electrocatalysis, and surface science. Since much of the work at National Laboratories is funded by DOE, the research is largely focused on addressing DOE's mission to ensure America's security and prosperity by addressing its energy, environmental, and nuclear challenges through transformative science and technology solutions. The catalysis research carried out at the DOE National Laboratories ranges from very fundamental catalysis science, funded by DOE's Office of Basic Energy Sciences (BES), to applied research and development (R&D)more » in areas such as biomass conversion to fuels and chemicals, fuel cells, and vehicle emission control with primary funding from DOE's Office of Energy Efficiency and Renewable Energy.« less

  2. Coupling chemical and biological catalysis: a flexible paradigm for producing biobased chemicals.

    PubMed

    Schwartz, Thomas J; Shanks, Brent H; Dumesic, James A

    2016-04-01

    Advances in metabolic engineering have allowed for the development of new biological catalysts capable of selectively de-functionalizing biomass to yield platform molecules that can be upgraded to biobased chemicals using high efficiency continuous processing allowed by heterogeneous chemical catalysis. Coupling these disciplines overcomes the difficulties of selectively activating COH bonds by heterogeneous chemical catalysis and producing petroleum analogues by biological catalysis. We show that carboxylic acids, pyrones, and alcohols are highly flexible platforms that can be used to produce biobased chemicals by this approach. More generally, we suggest that molecules with three distinct functionalities may represent a practical upper limit on the extent of functionality present in the platform molecules that serve as the bridge between biological and chemical catalysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Arizona Deafblind Project, 1995-1999. Final Report.

    ERIC Educational Resources Information Center

    Arizona State School for the Deaf and Blind, Tucson.

    This final report describes accomplishments of the four-year federally funded Arizona Deafblind Project which attempted to: (1) identify all deafblind children in Arizona; (2) deliver technical assistance to families; (3) deliver technical assistance to service providers; and (4) enhance community oversight, coordination, and collaboration with…

  4. Final Technical Report: Tandem and Bimetallic Catalysts for Oxidative Dehydrogenation of Light Hydrocarbon with Renewable Feedstock

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

    Abu-Omar, Mahdi

    2017-01-06

    An estimated 490 million metric tons of lignocellulosic biomass is available annually from U.S. agriculture and forestry. With continuing concerns over greenhouse gas emission, the development of efficient catalytic processes for conversion of biomass derived compounds is an important area of research. Since carbohydrates and polyols are rich in oxygen, approximately one oxygen atom per carbon, removal of hydroxyl groups via deoxygenation is needed. The necessary hydrogen required for hydrodeoxygenation (HDO) would either come from reforming biomass itself or from steam reforming of natural gas. Both processes contribute to global CO2 emission. The hope is that eventually renewable sources suchmore » as wind and solar for hydrogen production will become more viable and economic in the future. In the meantime, unconventional natural gas production in North America has boomed. As a result, light hydrocarbons present an opportunity when coupled with biomass derived oxygenates to generate valuable products from both streams without co-production of carbon dioxide. This concept is the focus of our current funding period. The objective of the project requires coupling two different types of catalysis, HDO and dehydrogenation. Our hypothesis was formulated around our success in establishing oxorhenium catalysts for polyol HDO reactions and known literature precedence for the use of iridium hydrides in alkane dehydrogenation. To examine our hypothesis we set out to investigate the reaction chemistry of binuclear complexes of oxorhenium and iridium hydride.« less

  5. Final technical report for the Center for Catalytic Hydrocarbon Functionalization (an EFRC)

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

    Gunnoe, Thomas Brent

    Greater than 95% of all materials produced by the chemical industry are derived from a small slate of simple hydrocarbons that are derived primarily from natural gas and petroleum, predominantly through oxygenation, C–C bond formation, halogenation or amination. Yet, current technologies for hydrocarbon conversion are typically high temperature, multi-step processes that are energy and capital intensive and result in excessive emissions (including carbon dioxide). The Center for Catalytic Hydrocarbon Functionalization (CCHF) brought together research teams with the broad coalition of skills and knowledge needed to make the fundamental advances in catalysis required for next-generation technologies to convert hydrocarbons (particularly lightmore » alkanes and methane) at high efficiency and low cost. Our new catalyst technologies offer many opportunities including enhanced utilization of natural gas in the transportation sector (via conversion to liquid fuels), more efficient generation of electricity from natural gas using direct methane fuel cells, reduced energy consumption and waste production for large petrochemical processes, and the preparation of high value molecules for use in biological/medical applications or the agricultural sector. The five year collaborative project accelerated fundamental understanding of catalyst design for the conversion of C–H bonds to functionalized products, essential to achieve the goals listed above, as evidenced by the publication of 134 manuscripts. Many of these fundamental advancements provide a foundation for potential commercialization, as evidenced by the submission of 11 patents from research support by the CCHF.« less

  6. Kokes Awards for the 25th North American Catalysis Society Meeting

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

    Pylypenko, Svitlana

    The biennial North American Catalysis Society (NACS) meeting is the premiere conferences in the area of catalysis, surface science, and reaction engineering. The 25th installment of this meeting will be held the week of June 4-9, 2017 in Denver, CO at the Hyatt Regency Hotel. Meeting objectives include bringing together leading researchers for intensive scientific exchange, providing students with an opportunity to present their work and interact with leaders in the field, and participate in service to scientific/technical community. Financial support to offset a portion of the associated costs – and specifically, registration fees, airline tickets, and hotel accommodations –more » encourages greater participation by graduate and undergraduate students, and often provides them the only opportunity to attend and meaningfully contribute to the conference. The funds sought in this proposal will be in support of the Richard J. Kokes Travel Award program. The eligibility criteria for undergraduates and graduate students applying for a merit-based Awards are that they must study at a university within the United States and present either a poster or presentation at the meeting. In the previous meeting in Pittsburgh, NACS received 200 applications and funded 110 students. Similarly, during the meeting in Louisville, NACS received 225 applications and funded nearly half of them. The NACS has an on-going tradition of encouraging graduate students (and more recently, undergraduates as well) to participate in and serve at the national meetings Providing financial support is one of the most effective means of accomplishing this goal. Their attendance significantly broadens their scientific training beyond what can be accomplished in the classroom, and offers them an opportunity to improve their communication and presentation skills. As an attendee to the 25th NAM, students will participate by listening to presentations from leading researchers from the U.S. and abroad, and they will be able to interact with them and receive invaluable advice regarding their research and future career. They will be able to meet with and debate with their peers from other universities, and learn about results from the latest technological innovations that could benefit their own research projects. Through their own service at the meeting – a requirement of the Kokes Travel Award – they will become active participating members of the catalysis community. The graduate and undergraduate students of today are the scientists and engineers of tomorrow. Proper training for them now leads to scientific breakthroughs and technological innovations in the future, and these in turn benefit the US economy. Catalysis permeates numerous aspects of our lives, and advances in the field result in more energy-efficient and environmentally-friendly chemical processes (e.g., catalytic convertors), improved fuel cell and battery performance and lifetimes, efficient alternative fuel and hydrogen production, enhanced utilization of biorenewable resources, and a cleaner environment.« less

  7. Heterogeneous Catalysis with Renewed Attention: Principles, Theories, and Concepts

    ERIC Educational Resources Information Center

    Dumeignil, Franck; Paul, Jean-Francois; Paul, Sebastien

    2017-01-01

    With the development of a strong bioeconomy sector related to the creation of next-generation biorefineries, heterogeneous catalysis is receiving renewed attention. Indeed, catalysis is at the core of biorefinery design, and many new catalysts and catalytic processes are being developed. On the one hand, they are based on knowledge acquired during…

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

    Chen, Jingguang; Frenkel, Anatoly; Rodriguez, Jose

    Synchrotron spectroscopies offer unique advantages over conventional techniques, including higher detection sensitivity and molecular specificity, faster detection rate, and more in-depth information regarding the structural, electronic and catalytic properties under in-situ reaction conditions. Despite these advantages, synchrotron techniques are often underutilized or unexplored by the catalysis community due to various perceived and real barriers, which will be addressed in the current proposal. Since its establishment in 2005, the Synchrotron Catalysis Consortium (SCC) has coordinated significant efforts to promote the utilization of cutting-edge catalytic research under in-situ conditions. The purpose of the current renewal proposal is aimed to provide assistance, andmore » to develop new sciences/techniques, for the catalysis community through the following concerted efforts: Coordinating the implementation of a suite of beamlines for catalysis studies at the new NSLS-II synchrotron source; Providing assistance and coordination for catalysis users at an SSRL catalysis beamline during the initial period of NSLS to NSLS II transition; Designing in-situ reactors for a variety of catalytic and electrocatalytic studies; Assisting experimental set-up and data analysis by a dedicated research scientist; Offering training courses and help sessions by the PIs and co-PIs.« less

  9. An Activity Switch in Human Telomerase Based on RNA Conformation and Shaped by TCAB1.

    PubMed

    Chen, Lu; Roake, Caitlin M; Freund, Adam; Batista, Pedro J; Tian, Siqi; Yin, Yi A; Gajera, Chandresh R; Lin, Shengda; Lee, Byron; Pech, Matthew F; Venteicher, Andrew S; Das, Rhiju; Chang, Howard Y; Artandi, Steven E

    2018-05-18

    Ribonucleoprotein enzymes require dynamic conformations of their RNA constituents for regulated catalysis. Human telomerase employs a non-coding RNA (hTR) with a bipartite arrangement of domains-a template-containing core and a distal three-way junction (CR4/5) that stimulates catalysis through unknown means. Here, we show that telomerase activity unexpectedly depends upon the holoenzyme protein TCAB1, which in turn controls conformation of CR4/5. Cells lacking TCAB1 exhibit a marked reduction in telomerase catalysis without affecting enzyme assembly. Instead, TCAB1 inactivation causes unfolding of CR4/5 helices that are required for catalysis and for association with the telomerase reverse-transcriptase (TERT). CR4/5 mutations derived from patients with telomere biology disorders provoke defects in catalysis and TERT binding similar to TCAB1 inactivation. These findings reveal a conformational "activity switch" in human telomerase RNA controlling catalysis and TERT engagement. The identification of two discrete catalytic states for telomerase suggests an intramolecular means for controlling telomerase in cancers and progenitor cells. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Joint Common Architecture Demonstration (JCA Demo) Final Report

    DTIC Science & Technology

    2016-07-28

    approach for implementing open systems [16], formerly known as the Modular Open Systems Approach (MOSA). OSA is a business and technical strategy to... TECHNICAL REPORT RDMR-AD-16-01 JOINT COMMON ARCHITECTURE DEMONSTRATION (JCA DEMO) FINAL REPORT Scott A. Wigginton... Modular Avionics .......................................................................... 5 E. Model-Based Engineering

  11. Molecular complexity from polyunsaturated substrates: the gold catalysis approach.

    PubMed

    Fensterbank, Louis; Malacria, Max

    2014-03-18

    Over the last two decades, electrophilic catalysis relying on platinum(II), gold(I), and gold(III) salts has emerged as a remarkable synthetic methodology. Chemists have discovered a large variety of organic transformations that convert a great assortment of highly functionalized precursors into valuable final products. In many cases, these methodologies offer unique features, allowing access to unprecedented molecular architectures. Due to the mild reaction conditions and high function compatibility, scientists have successfully developed applications in total synthesis of natural products, as well as in asymmetric catalysis. In addition, all these developments have been accompanied by the invention of well-tailored catalysts, so that a palette of different electrophilic agents is now commercially available or readily synthesized at the bench. In some respects, researchers' interests in developing homogeneous gold catalysis can be compared with the Californian gold rush of the 19th century. It has attracted into its fervor thousands of scientists, providing a huge number of versatile and important reports. More notably, it is clear that the contribution to the art of organic synthesis is very valuable, though the quest is not over yet. Because they rely on the intervention of previously unknown types of intermediates, new retrosynthetic disconnections are now possible. In this Account, we discuss our efforts on the use of readily available polyunsaturated precursors, such as enynes, dienynes, allenynes, and allenenes to give access to highly original polycyclic structures in a single operation. These transformations transit via previously undescribed intermediates A, B, D, F, and H that will be encountered later on. All these intermediates have been determined by both ourselves and others by DFT calculations and in some cases have been confirmed on the basis of experimental data. In addition, dual gold activation can be at work in some of these transformations, for instance, from E to F. Strikingly, we have found propargyl acetates to be particularly productive precursors. In a preliminary step upon electrophilic activation (complex I), they can lead to oxonium J or a vinylcarbenoid species K after 1,2-migration or complexed allenylester M from a formal 1,3-migration. All of them can serve as versatile entries for multievent processes. The propargyl cycle, sometimes called the golden carousel, involves species I-N), which lie in a close equilibrium. The control of this merry-go-round and its offshoots depends on the energy barriers associated with the subsequent reactions of these intermediates. We illustrate these themes in this Account, focusing on the intriguing characteristics of gold catalysis.

  12. Heteromultimetallic catalysis for sustainable organic syntheses.

    PubMed

    Lorion, Mélanie M; Maindan, Karan; Kapdi, Anant R; Ackermann, Lutz

    2017-12-07

    Fully complementary bimetallic catalysis has been identified as an increasingly powerful tool for molecular transformations, which was largely inspired by early examples of sequential catalytic transformations. Thus, energy-efficient one-pot reactions involving different metal catalysts orchestrated in concert constitute an attractive alternative to multi-step protocols, with major recent progress through the elegant ligand design in heterobimetallic catalysis as well as sustainable photo-induced C-H transformations, among others. This review provides a critical assessment of the state of the art in heterobimetallic catalysis for sustainable organic syntheses (SOS), highlighting key advances and representative examples until summer 2017.

  13. A Single-Site Platinum CO Oxidation Catalyst in Zeolite KLTL: Microscopic and Spectroscopic Determination of the Locations of the Platinum Atoms

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

    Kistler, Joseph D.; Chotigkrai, Nutchapon; Xu, Pinghong

    2014-07-01

    A stable site-isolated mononuclear platinum catalyst with a well-defined structure is presented. Platinum complexes supported in zeolite KLTL were synthesized from [Pt(NH 3) 4](NO 3) 2, oxidized at 633 K, and used to catalyze CO oxidation. Finally, IR and X-ray absorption spectra and electron micrographs determine the structures and locations of the platinum complexes in the zeolite pores, demonstrate the platinum-support bonding, and show that the platinum remained site isolated after oxidation and catalysis.

  14. Geometric Restraint Drives On- and Off-pathway Catalysis by the Escherichia coli Menaquinol:Fumarate Reductase*

    PubMed Central

    Tomasiak, Thomas M.; Archuleta, Tara L.; Andréll, Juni; Luna-Chávez, César; Davis, Tyler A.; Sarwar, Maruf; Ham, Amy J.; McDonald, W. Hayes; Yankovskaya, Victoria; Stern, Harry A.; Johnston, Jeffrey N.; Maklashina, Elena; Cecchini, Gary; Iverson, Tina M.

    2011-01-01

    Complex II superfamily members catalyze the kinetically difficult interconversion of succinate and fumarate. Due to the relative simplicity of complex II substrates and their similarity to other biologically abundant small molecules, substrate specificity presents a challenge in this system. In order to identify determinants for on-pathway catalysis, off-pathway catalysis, and enzyme inhibition, crystal structures of Escherichia coli menaquinol:fumarate reductase (QFR), a complex II superfamily member, were determined bound to the substrate, fumarate, and the inhibitors oxaloacetate, glutarate, and 3-nitropropionate. Optical difference spectroscopy and computational modeling support a model where QFR twists the dicarboxylate, activating it for catalysis. Orientation of the C2–C3 double bond of activated fumarate parallel to the C(4a)–N5 bond of FAD allows orbital overlap between the substrate and the cofactor, priming the substrate for nucleophilic attack. Off-pathway catalysis, such as the conversion of malate to oxaloacetate or the activation of the toxin 3-nitropropionate may occur when inhibitors bind with a similarly activated bond in the same position. Conversely, inhibitors that do not orient an activatable bond in this manner, such as glutarate and citrate, are excluded from catalysis and act as inhibitors of substrate binding. These results support a model where electronic interactions via geometric constraint and orbital steering underlie catalysis by QFR. PMID:21098488

  15. Geometric Restraint Drives On- and Off-pathway Catalysis by the Escherichia coli Menaquinol:Fumarate Reductase

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

    Tomasiak, Thomas M.; Archuleta, Tara L.; Andréll, Juni

    2012-01-05

    Complex II superfamily members catalyze the kinetically difficult interconversion of succinate and fumarate. Due to the relative simplicity of complex II substrates and their similarity to other biologically abundant small molecules, substrate specificity presents a challenge in this system. In order to identify determinants for on-pathway catalysis, off-pathway catalysis, and enzyme inhibition, crystal structures of Escherichia coli menaquinol:fumarate reductase (QFR), a complex II superfamily member, were determined bound to the substrate, fumarate, and the inhibitors oxaloacetate, glutarate, and 3-nitropropionate. Optical difference spectroscopy and computational modeling support a model where QFR twists the dicarboxylate, activating it for catalysis. Orientation of themore » C2-C3 double bond of activated fumarate parallel to the C(4a)-N5 bond of FAD allows orbital overlap between the substrate and the cofactor, priming the substrate for nucleophilic attack. Off-pathway catalysis, such as the conversion of malate to oxaloacetate or the activation of the toxin 3-nitropropionate may occur when inhibitors bind with a similarly activated bond in the same position. Conversely, inhibitors that do not orient an activatable bond in this manner, such as glutarate and citrate, are excluded from catalysis and act as inhibitors of substrate binding. These results support a model where electronic interactions via geometric constraint and orbital steering underlie catalysis by QFR.« less

  16. 76 FR 80226 - Technical Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... final rule, effective upon publication. Generally, the Administrative Procedure Act (APA) requires a.... Additionally, the APA requires that a final rule must have a delayed effective date of 30 days from the date of... delayed effective date requirement under the APA. 5 U.S.C. 553(d)(3). Again the technical change conforms...

  17. "Type Ia Supernovae: Tools for Studying Dark Energy" Final Technical Report

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

    Woosley, Stan; Kasen, Dan

    2017-05-10

    Final technical report for project "Type Ia Supernovae: Tools for the Study of Dark Energy" awarded jointly to scientists at the University of California, Santa Cruz and Berkeley, for computer modeling, theory and data analysis relevant to the use of Type Ia supernovae as standard candles for cosmology.

  18. 76 FR 50202 - National Technical Assistance and Dissemination Center for Children Who Are Deaf-Blind; Final...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ... DEPARTMENT OF EDUCATION [CFDA No. 84.326T] National Technical Assistance and Dissemination Center for Children Who Are Deaf-Blind; Final Extension of Project Period and Waiver AGENCY: Office of Special Education Programs, Office of Special Education and Rehabilitative Services, Department of...

  19. TADS Final Evaluation Report, 1980-81. Appendix S.

    ERIC Educational Resources Information Center

    Suarez, Tanya M.; And Others

    The document contains the final report of the Technical Assistance Development System (TADS), a program which provided technical assistance (TA) services to 53 Handicapped Children's Early Education Program (HCEEP) demonstration projects and 13 State Implementation Grants (SIGs). The evaluation report is divided into five sections. Section 1…

  20. From containers to catalysts: supramolecular catalysis within cucurbiturils.

    PubMed

    Pemberton, Barry C; Raghunathan, Ramya; Volla, Sabine; Sivaguru, Jayaraman

    2012-09-24

    Cucurbiturils are a family of molecular container compounds with superior molecular recognition properties. The use of cucurbiturils for supramolecular catalysis is highlighted in this concept. Both photochemical reactions as well as thermal transformations are reviewed with an eye towards tailoring substrates for supramolecular catalysis mediated by cucurbiturils. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. LDRD 2013 Annual Report: Laboratory Directed Research and Development Program Activities

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

    Bookless, W.

    This LDRD project establishes a research program led by Jingguang Chen, who has started a new position as a Joint Appointee between BNL and Columbia University as of FY2013. Under this project, Dr. Chen will establish a new program in catalysis science at BNL and Columbia University. The LDRD program will provide initial research funding to start research at both BNL and Columbia. At BNL, Dr. Chen will initiate laboratory research, including hiring research staff, and will collaborate with the existing BNL catalysis and electrocatalysis research groups. At Columbia, a subcontract to Dr. Chen will provide startup funding for hismore » laboratory research, including initial graduate student costs. The research efforts will be linked under a common Catalysis Program in Sustainable Fuels. The overall impact of this project will be to strengthen the BNL catalysis science program through new linked research thrusts and the addition of an internationally distinguished catalysis scientist.« less

  2. Bioinspired construction of multi-enzyme catalytic systems.

    PubMed

    Shi, Jiafu; Wu, Yizhou; Zhang, Shaohua; Tian, Yu; Yang, Dong; Jiang, Zhongyi

    2018-06-18

    Enzyme catalysis, as a green, efficient process, displays exceptional functionality, adaptivity and sustainability. Multi-enzyme catalysis, which can accomplish the tandem synthesis of valuable materials/chemicals from renewable feedstocks, establishes a bridge between single-enzyme catalysis and whole-cell catalysis. Multi-enzyme catalysis occupies a unique and indispensable position in the realm of biological reactions for energy and environmental applications. Two complementary strategies, i.e., compartmentalization and substrate channeling, have been evolved by living organisms for implementing the complex in vivo multi-enzyme reactions (MERs), which have been applied to construct multi-enzyme catalytic systems (MECSs) with superior catalytic activity and stabilities in practical biocatalysis. This tutorial review aims to present the recent advances and future prospects in this burgeoning research area, stressing the features and applications of the two strategies for constructing MECSs and implementing in vitro MERs. The concluding remarks are presented with a perspective on the construction of MECSs through rational combination of compartmentalization and substrate channeling.

  3. Toward benchmarking in catalysis science: Best practices, challenges, and opportunities

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

    Bligaard, Thomas; Bullock, R. Morris; Campbell, Charles T.

    Benchmarking is a community-based and (preferably) community-driven activity involving consensus-based decisions on how to make reproducible, fair, and relevant assessments. In catalysis science, important catalyst performance metrics include activity, selectivity, and the deactivation profile, which enable comparisons between new and standard catalysts. Benchmarking also requires careful documentation, archiving, and sharing of methods and measurements, to ensure that the full value of research data can be realized. Beyond these goals, benchmarking presents unique opportunities to advance and accelerate understanding of complex reaction systems by combining and comparing experimental information from multiple, in situ and operando techniques with theoretical insights derived frommore » calculations characterizing model systems. This Perspective describes the origins and uses of benchmarking and its applications in computational catalysis, heterogeneous catalysis, molecular catalysis, and electrocatalysis. As a result, it also discusses opportunities and challenges for future developments in these fields.« less

  4. Toward benchmarking in catalysis science: Best practices, challenges, and opportunities

    DOE PAGES

    Bligaard, Thomas; Bullock, R. Morris; Campbell, Charles T.; ...

    2016-03-07

    Benchmarking is a community-based and (preferably) community-driven activity involving consensus-based decisions on how to make reproducible, fair, and relevant assessments. In catalysis science, important catalyst performance metrics include activity, selectivity, and the deactivation profile, which enable comparisons between new and standard catalysts. Benchmarking also requires careful documentation, archiving, and sharing of methods and measurements, to ensure that the full value of research data can be realized. Beyond these goals, benchmarking presents unique opportunities to advance and accelerate understanding of complex reaction systems by combining and comparing experimental information from multiple, in situ and operando techniques with theoretical insights derived frommore » calculations characterizing model systems. This Perspective describes the origins and uses of benchmarking and its applications in computational catalysis, heterogeneous catalysis, molecular catalysis, and electrocatalysis. As a result, it also discusses opportunities and challenges for future developments in these fields.« less

  5. Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks

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

    DeBlase, Catherine R.; Dichtel, William R.

    Since their discovery in 2005, covalent organic frameworks (COFs) have attracted interest as potential materials for gas storage, catalysis, energy storage, and other applications because of their ability to periodically and reliably organize designed functionality into high surface area materials. Most of the first examples relied on boron-containing linkages, which suffer from hydrolytic and oxidative instability that limit their utility. In this Perspective, we describe the trend toward more robust linkages by highlighting the design, synthesis, and properties of several recent examples. Finally, the continued development of new COF chemistries, along with improved understanding of their formation and control ofmore » their final form, will provide a means to harness their molecularly precise solidstate structures for useful purposes.« less

  6. Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks

    DOE PAGES

    DeBlase, Catherine R.; Dichtel, William R.

    2016-06-21

    Since their discovery in 2005, covalent organic frameworks (COFs) have attracted interest as potential materials for gas storage, catalysis, energy storage, and other applications because of their ability to periodically and reliably organize designed functionality into high surface area materials. Most of the first examples relied on boron-containing linkages, which suffer from hydrolytic and oxidative instability that limit their utility. In this Perspective, we describe the trend toward more robust linkages by highlighting the design, synthesis, and properties of several recent examples. Finally, the continued development of new COF chemistries, along with improved understanding of their formation and control ofmore » their final form, will provide a means to harness their molecularly precise solidstate structures for useful purposes.« less

  7. Tandem catalysis: a new approach to polymers.

    PubMed

    Robert, Carine; Thomas, Christophe M

    2013-12-21

    The creation of polymers by tandem catalysis represents an exciting frontier in materials science. Tandem catalysis is one of the strategies used by Nature for building macromolecules. Living organisms generally synthesize macromolecules by in vivo enzyme-catalyzed chain growth polymerization reactions using activated monomers that have been formed within cells during complex metabolic processes. However, these biological processes rely on highly complex biocatalysts, thus limiting their industrial applications. In order to obtain polymers by tandem catalysis, homogeneous and enzyme catalysts have played a leading role in the last two decades. In the following feature article, we will describe selected published efforts to achieve these research goals.

  8. Multielectron, multisubstrate molecular catalysis of electrochemical reactions: Formal kinetic analysis in the total catalysis regime.

    PubMed

    Costentin, Cyrille; Nocera, Daniel G; Brodsky, Casey N

    2017-10-24

    Cyclic voltammetry responses are derived for two-electron, two-step homogeneous electrocatalytic reactions in the total catalysis regime. The models developed provide a framework for extracting kinetic information from cyclic voltammograms (CVs) obtained in conditions under which the substrate or cosubstrate is consumed in a multielectron redox process, as is particularly prevalent for very active catalysts that promote energy conversion reactions. Such determination of rate constants in the total catalysis regime is a prerequisite for the rational benchmarking of molecular electrocatalysts that promote multielectron conversions of small-molecule reactants. The present analysis is illustrated with experimental systems encompassing various limiting behaviors.

  9. First kinetic discrimination between carbon and oxygen reactivity of enols.

    PubMed

    García-Río, Luis; Mejuto, Juan C; Parajó, Mercedes; Pérez-Lorenzo, Moisés

    2008-11-07

    Nitrosation of enols shows a well-differentiated behavior depending on whether the reaction proceeds through the carbon (nucleophilic catalysis is observed) or the oxygen atom (general acid-base catalysis is observed). This is due to the different operating mechanisms for C- and O-nitrosation. Nitrosation of acetylacetone (AcAc) shows a simultaneous nucleophilic and acid-base catalysis. This simultaneous catalysis constitutes the first kinetic evidence of two independent reactions on the carbon and oxygen atom of an enol. The following kinetic study allows us to determine the rate constants for both reaction pathways. A similar reactivity of the nucleophilic centers with the nitrosonium ion is observed.

  10. Iminium and enamine catalysis in enantioselective photochemical reactions.

    PubMed

    Zou, You-Quan; Hörmann, Fabian M; Bach, Thorsten

    2018-01-22

    Although enantioselective catalysis under thermal conditions has been well established over the last few decades, the enantioselective catalysis of photochemical reactions is still a challenging task resulting from the complex enantiotopic face differentiation in the photoexcited state. Recently, remarkable achievements have been reported by a synergistic combination of organocatalysis and photocatalysis, which have led to the expedient construction of a diverse range of enantioenriched molecules which are generally not easily accessible under thermal conditions. In this tutorial review, we summarize and highlight the most significant advances in iminium and enamine catalysis of enantioselective photochemical reactions, with an emphasis on catalytic modes and reaction types.

  11. Iminium and enamine catalysis in enantioselective photochemical reactions

    PubMed Central

    Hörmann, Fabian M.

    2018-01-01

    Although enantioselective catalysis under thermal conditions has been well established over the last few decades, the enantioselective catalysis of photochemical reactions is still a challenging task resulting from the complex enantiotopic face differentiation in the photoexcited state. Recently, remarkable achievements have been reported by a synergistic combination of organocatalysis and photocatalysis, which have led to the expedient construction of a diverse range of enantioenriched molecules which are generally not easily accessible under thermal conditions. In this tutorial review, we summarize and highlight the most significant advances in iminium and enamine catalysis of enantioselective photochemical reactions, with an emphasis on catalytic modes and reaction types. PMID:29155908

  12. 78 FR 57264 - Final Waiver and Extension of the Project Period for the Technical Assistance Coordination Center

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-18

    ...: 84.326Z.] Final Waiver and Extension of the Project Period for the Technical Assistance Coordination... project period. SUMMARY: The Secretary waives the requirements in the Education Department General Administrative Regulations that generally prohibit project periods exceeding five years and extensions of project...

  13. 77 FR 16923 - Agreements and Memoranda of Understanding Between the Food and Drug Administration and Other...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-23

    ...: Direct final rule. SUMMARY: This direct final rule makes technical changes that will update a requirement that many of our written agreements and memoranda of understanding (MOUs) with other departments..., accordingly, eliminates it. We are making these technical changes to conserve Agency time and resources...

  14. 1988 Underground Storage Tanks; Technical Requirements; Final Rule and Underground Storage Tanks Containing Petroleum-Financial Responsibility Requirements and State Program Approval Objective; Final Rule

    EPA Pesticide Factsheets

    EPA's 1988 regulations concerning USTs are contained in 40 CFR Part 280, 40 CFR Part 281 and 40 CFR Parts 282.50-282.105 and divided into three sections: technical requirements, financial responsibility requirements, and state program approval objectives.

  15. PITTSBURGH TECHNICAL HEALTH TRAINING INSTITUTE DEMONSTRATION PROJECT. FINAL REPORT, VOLUME II.

    ERIC Educational Resources Information Center

    KISHKUNAS, LOUIS J.

    APPENDIXES TO THE "FINAL REPORT," VOLUME I (VT 005 511), ARE INCLUDED--(1) A SCHEMATIC REPRESENTATION OF CURRICULUM DEVELOPMENT, (2) TECHNICAL BEHAVIOR CHECKLISTS, (3) PERFORMANCE INVENTORY FORMS USED IN ON-THE-JOB OBSERVATIONS, (4) REPORT FORM FOR TYPICAL JOB BEHAVIOR OF EMPLOYEE, (5) COOPERATING AREA HEALTH INSTITUTIONS, (6) TABLES OF Z SCORES…

  16. Invention and Writing in Technical Work: Representing the Object.

    ERIC Educational Resources Information Center

    Winsor, Dorothy A.

    1994-01-01

    Describes the way invention is relevant to the practice of technical writing. Studies three engineering students engaged in a real-world project. Shows how the students' technical work and invention for the final report were simultaneous activities. Claims that invention for and through writing overlaps with technical invention. (HB)

  17. Project T.E.A.M. (Technical Education Advancement Modules). Final Report.

    ERIC Educational Resources Information Center

    Greenville Technical Coll., SC.

    Project TEAM (Technical Education Advancement Modules), a cooperative demonstration program for high technology training, created an introductory technical training program and a consumer education package emphasizing the benefits of technical training. The curriculum and training focus of the project began with an assessment of employee needs in…

  18. Reconstituting redox active centers of heme-containing proteins with biomineralized gold toward peroxidase mimics with strong intrinsic catalysis and electrocatalysis for H2O2 detection.

    PubMed

    Zhang, Liyan; Li, Shuai; Dong, Minmin; Jiang, Yao; Li, Ru; Zhang, Shuo; Lv, Xiaoxia; Chen, Lijun; Wang, Hua

    2017-01-15

    A facile and efficient enzymatic reconstitution methodology has been proposed for high-catalysis peroxidase mimics by remolding the redox active centers of heme-containing proteins with the in-site biomineralized gold using hemoglobin (Hb) as a model. Catalytic hemin (Hem) was extracted from the active centers of Hb for the gold biomineralization and then reconstituted into apoHb to yield the Hem-Au@apoHb nanocomposites showing dramatically improved intrinsic catalysis and electrocatalysis over natural Hb and Hem. The biomineralized gold, on the one hand, would act as "nanowires" to promote the electron transferring of the nanocomposites. On the other hand, it would create a reactivity pathway to pre-organize and accumulate more substrates towards the active sites of the peroxidase mimics. Steady-state kinetics studies indicate that Hem-Au@apoHb could present much higher substrate affinity (lower Michaelis constants) and intrinsic catalysis even than some natural peroxidases. Moreover, the application feasibility of the prepared artificial enzymes was demonstrated by colorimetric assays and direct electrocatalysis for H 2 O 2 sensing, showing a detection limitation low as 0.45μM. Importantly, such a catalysis active-center reconstitution protocol may circumvent the substantial improvement of the intrinsic catalysis and electrocatalysis of diverse heme-containing proteins or enyzmes toward the extensive applications in the chemical, enviromental, and biomedical catalysis fields. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. A paradigm shift for radical SAM reactions: The organometallic intermediate Ω is central to catalysis.

    PubMed

    Byer, Amanda S; Yang, Hao; McDaniel, Elizabeth C; Kathiresan, Venkatesan; Impano, Stella; Pagnier, Adrien; Watts, Hope; Denler, Carly; Vagstad, Anna; Piel, Jörn; Duschene, Kaitlin S; Shepard, Eric M; Shields, Thomas P; Scott, Lincoln G; Lilla, Edward A; Yokoyama, Kenichi; Broderick, William E; Hoffman, Brian M; Broderick, Joan B

    2018-06-28

    Radical S-adenosyl-L-methionine (SAM) en-zymes comprise a vast superfamily catalyzing diverse reactions essential to all life through ho-molytic SAM cleavage to liberate the highly-reactive 5-deoxyadenosyl radical (5-dAdo•). Our recent observation of a catalytically compe-tent organometallic intermediate Ω that forms dur-ing reaction of the radical SAM (RS) enzyme py-ruvate formate-lyase activating-enzyme (PFL-AE) was therefore quite surprising, and led to the question of its broad relevance in the superfamily. We now show that Ω in PFL-AE forms as an in-termediate under a variety of mixing order condi-tions, suggesting it is central to catalysis in this enzyme. We further demonstrate that Ω forms in a suite of RS enzymes chosen to span the totality of superfamily reaction types, implicating Ω as essential in catalysis across the RS superfamily. Finally, EPR and electron nuclear double reso-nance spectroscopy establish that Ω involves an Fe-C5 bond between 5-dAdo• and the [4Fe-4S] cluster. An analogous organometallic bond is found in the well-known adenosylcobalamin (co-enzyme B12) cofactor used to initiate radical reac-tions via a 5'-dAdo• intermediate. Generation of a 5'-dAdo• intermediate via homolytic metal-carbon bond cleavage thus appears to be similar for Ω and coenzyme B12. However coenzyme B12 is involved in enzymes catalyzing of only a small number (~12) of distinct reactions, while the RS superfamily has more than 100,000 distinct se-quences and over 80 reaction types character-ized to date. The appearance of Ω across the RS superfamily therefore dramatically enlarges the sphere of bio-organometallic chemistry in Nature.

  20. The DNA glycosylase AlkD uses a non-base-flipping mechanism to excise bulky lesions

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

    Mullins, Elwood A.; Shi, Rongxin; Parsons, Zachary D.

    Threats to genomic integrity arising from DNA damage are mitigated by DNA glycosylases, which initiate the base excision repair pathway by locating and excising aberrant nucleobases. How these enzymes find small modifications within the genome is a current area of intensive research. A hallmark of these and other DNA repair enzymes is their use of base flipping to sequester modified nucleotides from the DNA helix and into an active site pocket. Consequently, base flipping is generally regarded as an essential aspect of lesion recognition and a necessary precursor to base excision. In this paper, we present the first, to ourmore » knowledge, DNA glycosylase mechanism that does not require base flipping for either binding or catalysis. Using the DNA glycosylase AlkD from Bacillus cereus, we crystallographically monitored excision of an alkylpurine substrate as a function of time, and reconstructed the steps along the reaction coordinate through structures representing substrate, intermediate and product complexes. Instead of directly interacting with the damaged nucleobase, AlkD recognizes aberrant base pairs through interactions with the phosphoribose backbone, while the lesion remains stacked in the DNA duplex. Quantum mechanical calculations revealed that these contacts include catalytic charge–dipole and CH–π interactions that preferentially stabilize the transition state. We show in vitro and in vivo how this unique means of recognition and catalysis enables AlkD to repair large adducts formed by yatakemycin, a member of the duocarmycin family of antimicrobial natural products exploited in bacterial warfare and chemotherapeutic trials. Bulky adducts of this or any type are not excised by DNA glycosylases that use a traditional base-flipping mechanism. Finally and hence, these findings represent a new model for DNA repair and provide insights into catalysis of base excision.« less

  1. Tales of Dihydrofolate Binding to R67 Dihydrofolate Reductase

    PubMed Central

    2015-01-01

    Homotetrameric R67 dihydrofolate reductase possesses 222 symmetry and a single active site pore. This situation results in a promiscuous binding site that accommodates either the substrate, dihydrofolate (DHF), or the cofactor, NADPH. NADPH interacts more directly with the protein as it is larger than the substrate. In contrast, the p-aminobenzoyl-glutamate tail of DHF, as monitored by nuclear magnetic resonance and crystallography, is disordered when bound. To explore whether smaller active site volumes (which should decrease the level of tail disorder by confinement effects) alter steady state rates, asymmetric mutations that decreased the half-pore volume by ∼35% were constructed. Only minor effects on kcat were observed. To continue exploring the role of tail disorder in catalysis, 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide-mediated cross-linking between R67 DHFR and folate was performed. A two-folate, one-tetramer complex results in the loss of enzyme activity where two symmetry-related K32 residues in the protein are cross-linked to the carboxylates of two bound folates. The tethered folate could be reduced, although with a ≤30-fold decreased rate, suggesting decreased dynamics and/or suboptimal positioning of the cross-linked folate for catalysis. Computer simulations that restrain the dihydrofolate tail near K32 indicate that cross-linking still allows movement of the p-aminobenzoyl ring, which allows the reaction to occur. Finally, a bis-ethylene-diamine-α,γ-amide folate adduct was synthesized; both negatively charged carboxylates in the glutamate tail were replaced with positively charged amines. The Ki for this adduct was ∼9-fold higher than for folate. These various results indicate a balance between folate tail disorder, which helps the enzyme bind substrate while dynamics facilitates catalysis. PMID:26637016

  2. The DNA glycosylase AlkD uses a non-base-flipping mechanism to excise bulky lesions

    DOE PAGES

    Mullins, Elwood A.; Shi, Rongxin; Parsons, Zachary D.; ...

    2015-10-28

    Threats to genomic integrity arising from DNA damage are mitigated by DNA glycosylases, which initiate the base excision repair pathway by locating and excising aberrant nucleobases. How these enzymes find small modifications within the genome is a current area of intensive research. A hallmark of these and other DNA repair enzymes is their use of base flipping to sequester modified nucleotides from the DNA helix and into an active site pocket. Consequently, base flipping is generally regarded as an essential aspect of lesion recognition and a necessary precursor to base excision. In this paper, we present the first, to ourmore » knowledge, DNA glycosylase mechanism that does not require base flipping for either binding or catalysis. Using the DNA glycosylase AlkD from Bacillus cereus, we crystallographically monitored excision of an alkylpurine substrate as a function of time, and reconstructed the steps along the reaction coordinate through structures representing substrate, intermediate and product complexes. Instead of directly interacting with the damaged nucleobase, AlkD recognizes aberrant base pairs through interactions with the phosphoribose backbone, while the lesion remains stacked in the DNA duplex. Quantum mechanical calculations revealed that these contacts include catalytic charge–dipole and CH–π interactions that preferentially stabilize the transition state. We show in vitro and in vivo how this unique means of recognition and catalysis enables AlkD to repair large adducts formed by yatakemycin, a member of the duocarmycin family of antimicrobial natural products exploited in bacterial warfare and chemotherapeutic trials. Bulky adducts of this or any type are not excised by DNA glycosylases that use a traditional base-flipping mechanism. Finally and hence, these findings represent a new model for DNA repair and provide insights into catalysis of base excision.« less

  3. Hard and soft X-ray microscopy and tomography in catalysis: bridging the different time and length scales.

    PubMed

    Grunwaldt, Jan-Dierk; Schroer, Christian G

    2010-12-01

    X-ray microscopic techniques are excellent and presently emerging techniques for chemical imaging of heterogeneous catalysts. Spatially resolved studies in heterogeneous catalysis require the understanding of both the macro and the microstructure, since both have decisive influence on the final performance of the industrially applied catalysts. A particularly important aspect is the study of the catalysts during their preparation, activation and under operating conditions, where X-rays have an inherent advantage due to their good penetration length especially in the hard X-ray regime. Whereas reaction cell design for hard X-rays is straightforward, recently smart in situ cells have also been reported for the soft X-ray regime. In the first part of the tutorial review, the constraints from a catalysis view are outlined, then the scanning and full-field X-ray microscopy as well as coherent X-ray diffraction imaging techniques are described together with the challenging design of suitable environmental cells. Selected examples demonstrate the application of X-ray microscopy and tomography to monitor structural gradients in catalytic reactors and catalyst preparation with micrometre resolution but also the possibility to follow structural changes in the sub-100 nm regime. Moreover, the potential of the new synchrotron radiation sources with higher brilliance, recent milestones in focusing of hard X-rays as well as spatiotemporal studies are highlighted. The tutorial review concludes with a view on future developments in the field of X-ray microscopy that will have strong impact on the understanding of catalysts in the future and should be combined with in situ electron microscopic studies on the nanoscale and other spectroscopic studies like microRaman, microIR and microUV-vis on the macroscale.

  4. 77 FR 39623 - Airworthiness Standards: Aircraft Engines; Technical Amendment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-05

    ...] Airworthiness Standards: Aircraft Engines; Technical Amendment AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule; technical amendment. SUMMARY: This amendment clarifies aircraft engine... from applicants requesting FAA engine type certifications and aftermarket certifications, such as...

  5. Enzyme catalysis with small ionic liquid quantities.

    PubMed

    Fischer, Fabian; Mutschler, Julien; Zufferey, Daniel

    2011-04-01

    Enzyme catalysis with minimal ionic liquid quantities improves reaction rates, stereoselectivity and enables solvent-free processing. In particular the widely used lipases combine well with many ionic liquids. Demonstrated applications are racemate separation, esterification and glycerolysis. Minimal solvent processing is also an alternative to sluggish solvent-free catalysis. The method allows simplified down-stream processing, as only traces of ionic liquids have to be removed.

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

    Pruski, Marek; Sadow, Aaron D.; Slowing, Igor I.

    Here the catalysis research at the U.S. Department of Energy's (DOE's) National Laboratories covers a wide range of research topics in heterogeneous catalysis, homogeneous/molecular catalysis, biocatalysis, electrocatalysis, and surface science. Since much of the work at National Laboratories is funded by DOE, the research is largely focused on addressing DOE's mission to ensure America's security and prosperity by addressing its energy, environmental, and nuclear challenges through transformative science and technology solutions.

  7. Synthesis of Energetic Materials

    DTIC Science & Technology

    1988-03-01

    reacted with excess ethyl urethane, under boron trifluoride catalysis in trifluoroacetic acid, to give the 2,3-bisurethane derivative. This conversion... trifluoride catalysis, to give none of the imidazolidine (1), but only a low yield of the MEDINA derivative (5), via an obscure reaction pathway...trifluoroacetic acid under boron trifluoride catalysis. The major product, isolated in high yield, was the tricyclic ether (18). In fact, compound 18 was

  8. An electrochemical aptasensor for thrombin using synergetic catalysis of enzyme and porous Au@Pd core-shell nanostructures for signal amplification.

    PubMed

    Xu, Wenju; Yi, Huayu; Yuan, Yali; Jing, Pei; Chai, Yaqin; Yuan, Ruo; Wilson, George S

    2015-02-15

    In this work, a sensitive electrochemical aptasensor for thrombin (TB) based on synergetic catalysis of enzyme and porous Au@Pd core-shell nanostructure has been constructed. With the advantages of large surface area and outstanding catalytic performance, porous Au@Pd core-shell nanostructures were firstly employed as the nanocarrier for the immobilization of electroactive toluidine blue (Tb), hemin/G-quadruplex formed by intercalating hemin into the TB aptamer (TBA) and glucose oxidase (GOx). As a certain amount of glucose was added into the detection cell, GOx rapidly catalyzed the oxidation of glucose, coupling with the local generation of H2O2 in the presence of dissolved O2. Then, porous Au@Pd nanoparticles and hemin/G-quadruplex as the peroxidase mimics efficiently catalyzed the reduction of H2O2, amplifying the electrochemical signal and improving the sensitivity. Finally, a detection limit of 0.037pM for TB was achieved. The excellent performance of the aptasensor indicated its promising prospect as a valuable tool in simple and cost-effective TB detection in clinical application. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Current advances and trends in electro-Fenton process using heterogeneous catalysts - A review.

    PubMed

    Poza-Nogueiras, Verónica; Rosales, Emilio; Pazos, Marta; Sanromán, M Ángeles

    2018-06-01

    Over the last decades, advanced oxidation processes have often been used alone, or combined with other techniques, for remediation of ground and surface water pollutants. The application of heterogeneous catalysis to electrochemical advanced oxidation processes is especially useful due to its efficiency and environmental safety. Among those processes, electro-Fenton stands out as the one in which heterogeneous catalysis has been broadly applied. Thus, this review has introduced an up-to-date collation of the current knowledge of the heterogeneous electro-Fenton process, highlighting recent advances in the use of different catalysts such as iron minerals (pyrite, magnetite or goethite), prepared catalysts by the load of metals in inorganic and organic materials, nanoparticles, and the inclusion of catalysts on the cathode. The effects of physical-chemical parameters as well as the mechanisms involved are critically assessed. Finally, although the utilization of this process to remediation of wastewater overwhelmingly outnumber other utilities, several applications have been described in the context of regeneration of adsorbent or the remediation of soils as clear examples of the feasibility of the electro-Fenton process to solve different environmental problems. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Theoretical Heterogeneous Catalysis: Scaling Relationships and Computational Catalyst Design.

    PubMed

    Greeley, Jeffrey

    2016-06-07

    Scaling relationships are theoretical constructs that relate the binding energies of a wide variety of catalytic intermediates across a range of catalyst surfaces. Such relationships are ultimately derived from bond order conservation principles that were first introduced several decades ago. Through the growing power of computational surface science and catalysis, these concepts and their applications have recently begun to have a major impact in studies of catalytic reactivity and heterogeneous catalyst design. In this review, the detailed theory behind scaling relationships is discussed, and the existence of these relationships for catalytic materials ranging from pure metal to oxide surfaces, for numerous classes of molecules, and for a variety of catalytic surface structures is described. The use of the relationships to understand and elucidate reactivity trends across wide classes of catalytic surfaces and, in some cases, to predict optimal catalysts for certain chemical reactions, is explored. Finally, the observation that, in spite of the tremendous power of scaling relationships, their very existence places limits on the maximum rates that may be obtained for the catalyst classes in question is discussed, and promising strategies are explored to overcome these limitations to usher in a new era of theory-driven catalyst design.

  11. Transition metal catalysis in the generation of petroleum and natural gas. Final report

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

    Mango, F.D.

    1997-01-21

    This project originated on the premise that natural gas could be formed catalytically in the earth rather than thermally as commonly believed. The intention was to test this hypothetical view and to explore generally the role of sedimentary metals in the generation of light hydrocarbons (C1 - C9). We showed the metalliferous source rocks are indeed catalytic in the generation of natural gas. Various metal compounds in the pure state show the same levels of catalytic activity as sedimentary rocks and the products are identical. Nickel is particularly active among the early transition metals and is projected to remain catalyticallymore » robust at all stages of catagenesis. Nickel oxide promotes the formation of n-alkanes in addition to natural gas (NG), demonstrating the full scope of the hypothetical catalytic process: The composition of catalytic gas duplicates the entire range of natural gas, from so-called wet gas to dry gas (60 to 95+ wt % methane), while gas generated thermally is consistently depleted in methane (10 to 60 wt % methane). These results support the view that metal catalysis is a major pathway through which natural gas is formed in the earth.« less

  12. Transition metal catalysis in the generation of petroleum and natural gas. Final report, September 1, 1992--October 31, 1995

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

    Mango, F.D.

    1997-01-21

    This project originated on the premise that natural gas could be formed catalytically in the earth rather than thermally as commonly believed. The intention was to test this hypothetical view and to explore generally the role of sedimentary metals in the generation of light hydrocarbons (C1 - C9). We showed the metalliferous source rocks are indeed catalytic in the generation of natural gas. Various metal compounds in the pure state show the same levels of catalytic activity as sedimentary rocks and the products are identical. Nickel is particularly active among the early transition metals and is projected to remain catalyticallymore » robust at all stages of catagenesis. Nickel oxide promotes the formation of n-alkanes in addition to natural gas (NG), demonstrating the full scope of the hypothetical catalytic process. The composition of catalytic gas duplicates the entire range of natural gas, from so-called wet gas to dry gas (60 to 95+ wt % methane), while gas generated thermally is consistently depleted in methane (10 to 60 wt % methane). These results support the view that metal catalysis is a major pathway through which natural gas is formed in the earth.« less

  13. Catalysis and co-catalysis of bond cleavages in coal and coal analogs. Final report, August 1, 1990--January 31, 1994

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

    Miller, B.

    1994-05-01

    In work prior to the inception of this project, the authors observed that mixtures of phenolic materials and polyalkoxyaromatic molecules were appreciably more effective in catalyzing the decompositions of di-2-naphthyl ether and of di-1-naphthyl sulfide in tetralin solutions at 450{degrees}C than were the phenols by themselves, even though the polyalkoxyaromatic molecules, in the absence of phenolic co- catalysts, show essentially no catalytic activity. This was of appreciable interest in coal research because dinapthyl ether and dinapthyl sulfide have been employed as model compounds for coals in studies aimed at cleaving ether and sulfide bonds similar to those in coals. Themore » authors proposed (R. K. Sharma, K. P. Raman, and B. Miller) that the mixed catalysts used in these studies catalyze cleavages of ether and sulfide bonds by means of a mechanism involving electron transfer from the polyalkoxyaromatics to the substrates, which are activated as electron acceptors by hydrogen bonding to phenols. Since phenols themselves are electron donors, they also proposed that the well known effects of phenols in catalyzing the conversion of coals are due to similar electron transfer mechanisms.« less

  14. TEMPO functionalized C60 fullerene deposited on gold surface for catalytic oxidation of selected alcohols

    NASA Astrophysics Data System (ADS)

    Piotrowski, Piotr; Pawłowska, Joanna; Sadło, Jarosław Grzegorz; Bilewicz, Renata; Kaim, Andrzej

    2017-05-01

    C60TEMPO10 catalytic system linked to a microspherical gold support through a covalent S-Au bond was developed. The C60TEMPO10@Au composite catalyst had a particle size of 0.5-0.8 μm and was covered with the fullerenes derivative of 2.3 nm diameter bearing ten nitroxyl groups; the organic film showed up to 50 nm thickness. The catalytic composite allowed for the oxidation under mild conditions of various primary and secondary alcohols to the corresponding aldehyde and ketone analogues with efficiencies as high as 79-98%, thus giving values typical for homogeneous catalysis, while retaining at the same time all the advantages of heterogeneous catalysis, e.g., easy separation by filtration from the reaction mixture. The catalytic activity of the resulting system was studied by means of high pressure liquid chromatography. A redox mechanism was proposed for the process. In the catalytic cycle of the oxidation process, the TEMPO moiety was continuously regenerated in situ with an applied primary oxidant, for example, O2/Fe3+ system. The new intermediate composite components and the final catalyst were characterized by various spectroscopic methods and thermogravimetry.

  15. 7 CFR 652.36 - Appeal of decertification decisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... technical service provider's written appeal, the Chief or his designee, will make a final determination, in... CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE SUPPORT ACTIVITIES TECHNICAL SERVICE PROVIDER ASSISTANCE... of the State Conservationist's decertification determination, the technical service provider may...

  16. Capturing Cognitive Fingerprints for Active Authentication

    DTIC Science & Technology

    2014-10-01

    CAPTURING COGNITIVE FINGERPRINTS FOR ACTIVE AUTHENTICATION IOWA STATE UNIVERSITY OF SCIENCE & TECHNOLOGY OCTOBER 2014 FINAL TECHNICAL REPORT...REPORT TYPE FINAL TECHNICAL REPORT 3. DATES COVERED (From - To) SEP 2013 – APR 2014 4. TITLE AND SUBTITLE CAPTURING COGNITIVE FINGERPRINTS FOR ACTIVE...The project ended before the IRB application was approved. 15. SUBJECT TERMS Active Authentication, Cognitive Fingerprints , Biometric Modalities

  17. Application of Communications Satellites to Educational Development. Final Technical Report, September 1, 1969-August 31, 1975.

    ERIC Educational Resources Information Center

    Morgan, Robert P.

    Research is summarized in a brief final report built around a four-section bibliography. The first section lists periodic progress reports and articles which provide an overview of the program, including articles which pertain primarily to educational rather than technical aspects of satellite utilization. Theses carried out in the fields of…

  18. Head Start Impact Study. Technical Report

    ERIC Educational Resources Information Center

    Puma, Michael; Bell, Stephen; Cook, Ronna; Heid, Camilla; Shapiro, Gary; Broene, Pam; Jenkins, Frank; Fletcher, Philip; Quinn, Liz; Friedman, Janet; Ciarico, Janet; Rohacek, Monica; Adams, Gina; Spier, Elizabeth

    2010-01-01

    This Technical Report is designed to provide technical detail to support the analysis and findings presented in the "Head Start Impact Study Final Report" (U.S. Department of Health and Human Services, January 2010). Chapter 1 provides an overview of the Head Start Impact Study and its findings. Chapter 2 provides technical information on the…

  19. Matching Community and Technical College Professional/Technical Education Capacity to Employer Demand. Final Report.

    ERIC Educational Resources Information Center

    Sommers, Paul; Heg, Deena

    A project was conducted to improve the state of Washington's community and technical college system by developing and using an improved occupational forecasting system to assess and respond to education and training needs. First, long-term occupational forecast data from Washington's Employment Security Department were matched with technical and…

  20. 75 FR 5784 - Guidance on Preparation of Market-Based Rate Filings and Electric Quarterly Reports by Public...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-04

    ... Preparation of Market-Based Rate Filings and Electric Quarterly Reports by Public Utilities; Notice of Technical Conference January 28, 2010. Take notice that Commission staff will convene a technical conference... final agenda of the technical conference. The March 3, 2010 technical conference will focus on the...

  1. A Revision of Technical Mathematics Based on the NCTM Standards. Final Report.

    ERIC Educational Resources Information Center

    Near, Barbara

    Between 1993 and 1996, Henry Ford Community College (Michigan) worked with business, industry, and technical instructors to revise their Technical Mathematics program in accordance with the National Council of Teachers of Mathematics (NCTM) Standards. The purpose of the project was to restructure the technical math curriculum and create a context…

  2. 76 FR 11327 - Technical Amendments to Rule 17a-8: Financial Recordkeeping and Reporting of Currency and Foreign...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-02

    ... SECURITIES AND EXCHANGE COMMISSION 17 CFR Part 240 [Release No. 34-63949] Technical Amendments to...: Securities and Exchange Commission. ACTION: Final rule; technical amendments. SUMMARY: The Securities and Exchange Commission (``Commission'') is adopting technical amendments to Rule 17a-8 under the Securities...

  3. Final priority; technical assistance to improve state data capacity--National Technical Assistance Center to improve state capacity to accurately collect and report IDEA data. Final priority.

    PubMed

    2013-05-20

    The Assistant Secretary for Special Education and Rehabilitative Services announces a priority under the Technical Assistance to Improve State Data Capacity program. The Assistant Secretary may use this priority for competitions in fiscal year (FY) 2013 and later years. We take this action to focus attention on an identified national need to provide technical assistance (TA) to States to improve their capacity to meet the data collection and reporting requirements of the Individuals with Disabilities Education Act (IDEA). We intend this priority to establish a TA center to improve State capacity to accurately collect and report IDEA data (Data Center).

  4. Technical Evaluation Motor No. 10 (TEM-10)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Technical Evaluation Motor No. 10 (TEM-10) was static fired on 27 Apr. 1993 at the Thiokol Corporation full-scale motor static test bay, T-24. This final test report documents the procedures, performance, and results of the static test firing of TEM-10. All observations, discussions, conclusions, and recommendations contained are final. Included is a presentation and discussion of TEM-10 performance, anomalies, and test results in concurrence with the objectives outlined in CTP-0110, Revision D, Space Shuttle Technical Evaluation Motor No. 10 (TEM-10) Static Fire Test Plan.

  5. Final priority; Technical Assistance on State Data Collection--IDEA Data Management Center. Final priority.

    PubMed

    2014-08-05

    The Assistant Secretary for the Office of Special Education and Rehabilitative Services (OSERS) announces a priority under the Technical Assistance on State Data Collection program. The Assistant Secretary may use this priority for competitions in fiscal year (FY) 2014 and later years. We take this action to fund a cooperative agreement to establish and operate an IDEA Data Management Center (Center) that will provide technical assistance (TA) to improve the capacity of States to meet the data collection requirements of the Individuals with Disabilities Education Act (IDEA).

  6. Technical Topic 3.2.2.d Bayesian and Non-Parametric Statistics: Integration of Neural Networks with Bayesian Networks for Data Fusion and Predictive Modeling

    DTIC Science & Technology

    2016-05-31

    and included explosives such as TATP, HMTD, RDX, RDX, ammonium nitrate , potassium perchlorate, potassium nitrate , sugar, and TNT. The approach...Distribution Unlimited UU UU UU UU 31-05-2016 15-Apr-2014 14-Jan-2015 Final Report: Technical Topic 3.2.2. d Bayesian and Non- parametric Statistics...of Papers published in non peer-reviewed journals: Final Report: Technical Topic 3.2.2. d Bayesian and Non-parametric Statistics: Integration of Neural

  7. Aurophilicity in gold(I) catalysis: for better or worse?

    PubMed

    Weber, Dieter; Gagné, Michel R

    2015-01-01

    This book chapter discusses the effects of aurophilicity on gold catalysis. First, a brief historic account of aurophilicity in organogold chemistry is given, focusing on the pioneering results which set the stage for its association with catalytic intermediates (gold vinyl and gold aryl complexes); this is followed by an introduction to cationic gold(I) as an electrophilic catalyst, and the first isolation of organogold intermediates from catalysis. In the main section, the growing number of reports observing aurophilic interactions in catalysis or illustrative model systems is reviewed in a non-comprehensive tutorial way. The effects of aurophilicity are discussed in the following structures: (1) the geminal diauration of C(sp²)-atoms; (2) geminal diauration of other atoms; (3) σ-π-diauration of terminal alkynes. It is apparent that in most cases efficient catalysis is hindered by aurophilic effects as less active aggregates tend to be formed from more active species [LAu]⁺, but there are a growing number of reports using aurophilicity as a driving force to access new reactivity and selectivity.

  8. Catalysis in prebiotic chemistry RNA synthesis

    NASA Astrophysics Data System (ADS)

    Ferris, J.; Joshi, P.; Wang, K.; Huang, W.; Miyakawa, S.

    It is proposed that catalysis by minerals and metal ions had a central role in the steps that led to the origins of life. In particular, the formation of biopolymers in the presence of water requires catalysis to compete with hydrolytic processes. Catalysis is required to limit the number of isomers generated so that the longer polymers necessary for the origins of life formed. Montmorillonite clay catalyzes the formation of 6 14 mers of RNA from activated monomers of A, G, U and C in- aqueous solution. Daily addition of activated monomers to a 10 mer primer results in the formation of 40-50 mers of adenylic acid and 30 mers of uridylic acid. The sequence selectivity and regioselectivity in phosphodiester bond formation results from the montmorillonite catalysis. Reaction of D, L-activated monomers of A and U leads to the preferential formation of homochiral dimers (eg. D, D and L, L-- pApA). These data and any more recent developments will be discussed.

  9. Robustness of the Rotary Catalysis Mechanism of F1-ATPase*

    PubMed Central

    Watanabe, Rikiya; Matsukage, Yuki; Yukawa, Ayako; Tabata, Kazuhito V.; Noji, Hiroyuki

    2014-01-01

    F1-ATPase (F1) is the rotary motor protein fueled by ATP hydrolysis. Previous studies have suggested that three charged residues are indispensable for catalysis of F1 as follows: the P-loop lysine in the phosphate-binding loop, GXXXXGK(T/S); a glutamic acid that activates water molecules for nucleophilic attack on the γ-phosphate of ATP (general base); and an arginine directly contacting the γ-phosphate (arginine finger). These residues are well conserved among P-loop NTPases. In this study, we investigated the role of these charged residues in catalysis and torque generation by analyzing alanine-substituted mutants in the single-molecule rotation assay. Surprisingly, all mutants continuously drove rotary motion, even though the rotational velocity was at least 100,000 times slower than that of wild type. Thus, although these charged residues contribute to highly efficient catalysis, they are not indispensable to chemo-mechanical energy coupling, and the rotary catalysis mechanism of F1 is far more robust than previously thought. PMID:24876384

  10. Implementation of the multi-channel monolith reactor in an optimisation procedure for heterogeneous oxidation catalysts based on genetic algorithms.

    PubMed

    Breuer, Christian; Lucas, Martin; Schütze, Frank-Walter; Claus, Peter

    2007-01-01

    A multi-criteria optimisation procedure based on genetic algorithms is carried out in search of advanced heterogeneous catalysts for total oxidation. Simple but flexible software routines have been created to be applied within a search space of more then 150,000 individuals. The general catalyst design includes mono-, bi- and trimetallic compositions assembled out of 49 different metals and depleted on an Al2O3 support in up to nine amount levels. As an efficient tool for high-throughput screening and perfectly matched to the requirements of heterogeneous gas phase catalysis - especially for applications technically run in honeycomb structures - the multi-channel monolith reactor is implemented to evaluate the catalyst performances. Out of a multi-component feed-gas, the conversion rates of carbon monoxide (CO) and a model hydrocarbon (HC) are monitored in parallel. In combination with further restrictions to preparation and pre-treatment a primary screening can be conducted, promising to provide results close to technically applied catalysts. Presented are the resulting performances of the optimisation process for the first catalyst generations and the prospect of its auto-adaptation to specified optimisation goals.

  11. 2010 CATALYSIS GORDON RESEARCH CONFERENCE, JUNE 27 - JULY 2, 2010, NEW LONDON, NEW HAMPSHIRE

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

    Abhaya Datye

    2010-07-02

    Catalysis is a key technology for improving the quality of life while simultaneously reducing the adverse impact of human activities on the environment. The discovery of new catalytic processes and the improvement of existing ones are also critically important for securing the nation's energy supply. The GRC on Catalysis is considered one the most prestigious conference for catalysis research, bringing together leading researchers from both academia, industry and national labs to discuss the latest, most exciting research in catalysis and the future directions for the field. The 2010 GRC on Catalysis will follow time-honored traditions and feature invited talks frommore » the world's leading experts in the fundamentals and applications of catalytic science and technology. We plan to have increased participation from industry. The extended discussions in the company of outstanding thinkers will stimulate and foster new science. The conference will include talks in the following areas: Alternative feedstocks for chemicals and fuels, Imaging and spectroscopy, Design of novel catalysts, Catalyst preparation fundamentals, Molecular insights through theory, Surface Science, Catalyst stability and dynamics. In 2010, the Catalysis conference will move to a larger conference room with a new poster session area that will allow 40 posters per session. The dorm rooms provide single and double accommodations, free WiFi and the registration fee includes all meals and the famous lobster dinner on Thursday night. Afternoons are open to enjoy the New England ambiance with opportunities for hiking, sailing, golf and tennis to create an outstanding conference that will help you network with colleagues, and make long lasting connections.« less

  12. Final June Revisions Rule Significant Contribution Assessment TSD

    EPA Pesticide Factsheets

    This Technical Support Document (TSD) presents quantitative assessments of the relationship between the final February revisions to the Transport Rule, the final June revisions rule, and the original analysis conducted for the final Transport Rule.

  13. The Influence of Marine Microfouling on the Corrosion Behaviour of Passive Materials and Copper Alloys

    DTIC Science & Technology

    2008-01-02

    to organometallic catalysis, acidification of the electrode surface, the combined effects of elevated H20 2 and decreased pH and the production of...Ennoblement in marine waters has been ascribed to depolarization of the oxygen reduction reaction due to organometallic catalysis, acidification of the...organometallic catalysis, acidification of the electrode surface, the combined effects of elevated hydrogen peroxide (H202) and decreased pH and the production

  14. Develop a Comprehensive Technical Training and Data Collection Program for Structural Welders and Fitters: Technical Proposal

    DTIC Science & Technology

    2006-05-30

    implementation Final Report 4 TECHNICAL PLAN AND RESULTS Task 1: Initiate the Project Management System Two senior NGSS production management...1 Technical Plan and Results...Third the system is hosted on a handheld unit which provides the foremen with an efficient daily planning tool. The Pilot System which entails

  15. Recent advances in heterobimetallic catalysis across a "transition metal-tin" motif.

    PubMed

    Das, Debjit; Mohapatra, Swapna Sarita; Roy, Sujit

    2015-06-07

    Heterobimetallic catalysts, bearing a metal-metal bond between a transition metal (TM) and a tin atom, are very promising due to their ability in mediating a wide variety of organic transformations. Indeed the utilization of such catalysts is a challenging and evolving area in the field of homogeneous catalysis. Catalysis across a 'TM-Sn' motif is an emerging area in the broader domain of multimetallic catalysis. The present review apprises the chemists' community of the past, present and future scope of this versatile catalytic motif. The TM-Sn catalyzed reactions presented include, among others, Friedel-Crafts alkylation, carbonylation, polymerization, cyclization, olefin metathesis, Heck coupling, hydroarylation Michael addition and tandem coupling. The mechanistic aspects of the reactions have been highlighted as well.

  16. Laser Technician Associate Degree Program. A Proposal Submitted to Wisconsin State Board of Vocational, Technical, and Adult Education. (Curriculum Development.) Final Report.

    ERIC Educational Resources Information Center

    North Central Technical Inst., Wausau, WI.

    This final report contains the program proposal with supporting data for developing curriculum materials for and implementing an associate-degree laser technology program at the North Central Technical Institute. The proposal outline provides this information: (1) objectives for the program designed to prepare a technician to safely operate,…

  17. California Deaf-Blind Services Final Report, October 1, 1995-September 30, 1999 [and] October 1, 1999-June 30, 2000 (No Cost Extension).

    ERIC Educational Resources Information Center

    Goertz, Lori; Franklin, Barbara

    This final report describes the activities and outcomes of the California Deaf-Blind Services (CDBS) program, a regionally based, family focused technical assistance and training project designed to improve services to children with deaf-blindness. The project conducted the following activities: (1) provided technical assistance to families and…

  18. New Jersey Technical Assistance Project (N.J. TAP): "Educational Resources and Support Services on Behalf of Children with Multiple Sensory Impairment." Final Report.

    ERIC Educational Resources Information Center

    New Jersey State Dept. of Education, Trenton.

    This final report describes activities and accomplishments of the New Jersey Technical Assistance Project, a project to improve educational resources and support services for students with multiple sensory impairment (deaf-blindness). Activities and accomplishments are presented in a tabular format for each project goal and objective. The project…

  19. 78 FR 77563 - Technical Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ... NATIONAL CREDIT UNION ADMINISTRATION 12 CFR Parts 700, 701, and 704 RIN 3133-AE33 Technical Amendments AGENCY: National Credit Union Administration (NCUA). ACTION: Final rule. SUMMARY: The NCUA Board... credit unions. The technical amendments conform the regulations to a recent policy change adopted by the...

  20. 75 FR 33682 - Export Administration Regulations; Technical Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-15

    ...-01] RIN 0694-AE93 Export Administration Regulations; Technical Amendments AGENCY: Bureau of Industry... Bureau of Industry and Security (BIS) makes a technical amendment to the Export Administration... review of final decisions and orders issued in BIS export control administrative enforcement proceedings...

  1. 78 FR 41331 - Defense Federal Acquisition Regulation Supplement; Technical Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ... DEPARTMENT OF DEFENSE Defense Acquisition Regulations System 48 CFR Part 225 Defense Federal Acquisition Regulation Supplement; Technical Amendments AGENCY: Defense Acquisition Regulations System, Department of Defense (DoD). ACTION: Final rule. SUMMARY: DoD is making technical amendment to the Defense...

  2. CATALYTIC PROPERTIES OF SEMICONDUCTORS.

    DTIC Science & Technology

    SEMICONDUCTORS, CATALYSTS), (*CATALYSIS, REACTION KINETICS), (* SODIUM COMPOUNDS, TUNGSTATES), (*GALLIUM ALLOYS, ARSENIC ALLOYS), (*YTTERBIUM...COMPOUNDS, SILICIDES ), (*GERMANIUM, CATALYSIS), INTERNAL CONVERSION, EXCHANGE REACTIONS, HEAT OF ACTIVATION, THERMODYNAMICS, DEUTERIUM, POWDERS, SURFACES, HYDROGEN

  3. Final Revisions Rule Significant Contribution Assessment TSD

    EPA Pesticide Factsheets

    This Technical Support Document (TSD) presents quantitative assessments of the relationship between final revisions to the Transport Rule and the original analysis conducted for the final Transport Rule.

  4. Lattice Boltzmann Modeling of Complex Flows for Engineering Applications

    NASA Astrophysics Data System (ADS)

    Montessori, Andrea; Falcucci, Giacomo

    2018-01-01

    Nature continuously presents a huge number of complex and multiscale phenomena, which in many cases, involve the presence of one or more fluids flowing, merging and evolving around us. Since the very first years of the third millennium, the Lattice Boltzmann method (LB) has seen an exponential growth of applications, especially in the fields connected with the simulation of complex and soft matter flows. LB, in fact, has shown a remarkable versatility in different fields of applications from nanoactive materials, free surface flows, and multiphase and reactive flows to the simulation of the processes inside engines and fluid machinery. In this book, the authors present the most recent advances of the application of the LB to complex flow phenomena of scientific and technical interest with focus on the multiscale modeling of heterogeneous catalysis within nano-porous media and multiphase, multicomponent flows.

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

    Waterman, Michael R.

    Our understanding of the classification, function, mechanism, and structure of the enzymes which incorporate atoms of oxygen from atmospheric molecular oxygen during catalysis is based on the thoughtful and technically challenging experiments of two giants in the field of Biochemistry, Howard Mason and Osamu Hayaishi. This volume celebrates the 50th anniversary of the discovery and characterization of these 'oxygenase' enzymes and provides a broad view of how far this area of research has advanced. Professor Hayaishi describes herein his perspective on the background and major discoveries which led to the development of this field. Regrettably Howard Mason passed away atmore » age 88 in 2003. I am indeed fortunate to have been a Ph.D. student with Howard and to have the opportunity to briefly review his role in the development of this field for this special commemorative issue of BBRC.« less

  6. 75 FR 15342 - Advisory Committees; Technical Amendment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-29

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 14 [Docket No. FDA-2010-N-0001] Advisory Committees; Technical Amendment Agency: Food and Drug Administration, HHS. ACTION: Final rule; technical amendment. SUMMARY: The Food and Drug Administration (FDA) is amending its...

  7. Combining silver catalysis and organocatalysis: a sequential Michael addition/hydroalkoxylation one-pot approach to annulated coumarins.

    PubMed

    Hack, Daniel; Chauhan, Pankaj; Deckers, Kristina; Hermann, Gary N; Mertens, Lucas; Raabe, Gerhard; Enders, Dieter

    2014-10-03

    A highly stereoselective one-pot procedure for the synthesis of five-membered annulated hydroxycoumarins has been developed. By merging primary amine catalysis with silver catalysis, a series of functionalized coumarin derivatives were obtained in good yields (up to 91%) and good to excellent enantioselectivities (up to 99% ee) via a Michael addition/hydroalkoxylation reaction. Depending on the substituents on the enynone, the synthesis of annulated six-membered rings is also feasible.

  8. Enantioselective α-Alkylation of Aldehydes via Photoredox Organocatalysis: Rapid Access to Pharmacophore Fragments from β-Cyanoaldehydes**

    PubMed Central

    Welin, Eric R.; Warkentin, Alexander A.; Conrad, Jay C.

    2015-01-01

    The combination of photoredox catalysis and enamine catalysis has enabled the development of an enantioselective α-cyanoalkylation of aldehydes. This synergistic catalysis protocol allows for the coupling of two highly versatile yet orthogonal functionalities, allowing rapid diversification of the oxonitrile products to a wide array of medicinally relevant derivatives and heterocycles. This methodology has also been applied to the total synthesis of the lignan natural product (−)-bursehernin. PMID:26130043

  9. Reaction of azides and enolisable aldehydes under the catalysis of organic bases and Cinchona based quaternary ammonium salts.

    PubMed

    Destro, Dario; Sanchez, Sandra; Cortigiani, Mauro; Adamo, Mauro F A

    2017-06-21

    Herein we report a two-step sequence for the preparation of amides starting from azides and enolisable aldehydes. The reaction proceeded via the formation of triazoline intermediates that were converted into amides via Lewis acid catalysis. Preliminary studies on the preparation of triazolines under chiral phase transfer catalysis are also presented, demonstrating that enantioenriched amides could be prepared from achiral aldehydes in moderate to low enantioselectivity.

  10. 2012 Technical Corrections Fact Sheet

    EPA Pesticide Factsheets

    Final Rule: 2012 Technical Corrections, Clarifying and Other Amendments to theGreenhouse Gas Reporting Rule, and Confidentiality Determinations for Certain DataElements of the Fluorinated Gas Source Category

  11. Laguerre-polynomial-weighted squeezed vacuum: generation and its properties of entanglement

    NASA Astrophysics Data System (ADS)

    Ye, Wei; Zhang, Kuizheng; Zhang, Haoliang; Xu, Xuexiang; Hu, Liyun

    2018-02-01

    We theoretically prepare a kind of two-mode entangled non-Gaussian state generated by combining quantum catalysis and parametric-down amplifier operated on the two-mode squeezing vacuum state. We then investigate the entanglement properties by examining Von Neumann entropy, EPR correlation, squeezing effect and the fidelity of teleportation. It is shown that only Von Neumann entropy can be enhanced by both single- and two-mode catalysis in a small squeezing region, while the other properties can be enhanced only by two-mode catalysis including symmetrical and asymmetrical cases. A comparison among these properties shows that the squeezing and the EPR correlation definitely lead to the improvement of both the entanglement and the fidelity, and the region of enhanced fidelity can be seen as a sub-region of the enhanced entanglement which indicates that the entanglement is not always beneficial for the fidelity. In addition, the effect of photon-loss after catalysis on the fidelity is considered and the symmetrical two-photon catalysis may present better behavior than the symmetrical single-photon case against the decoherence in a certain region.

  12. Valence bond and enzyme catalysis: a time to break down and a time to build up.

    PubMed

    Sharir-Ivry, Avital; Varatharaj, Rajapandian; Shurki, Avital

    2015-05-04

    Understanding enzyme catalysis and developing ability to control of it are two great challenges in biochemistry. A few successful examples of computational-based enzyme design have proved the fantastic potential of computational approaches in this field, however, relatively modest rate enhancements have been reported and the further development of complementary methods is still required. Herein we propose a conceptually simple scheme to identify the specific role that each residue plays in catalysis. The scheme is based on a breakdown of the total catalytic effect into contributions of individual protein residues, which are further decomposed into chemically interpretable components by using valence bond theory. The scheme is shown to shed light on the origin of catalysis in wild-type haloalkane dehalogenase (wt-DhlA) and its mutants. Furthermore, the understanding gained through our scheme is shown to have great potential in facilitating the selection of non-optimal sites for catalysis and suggesting effective mutations to enhance the enzymatic rate. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes.

    PubMed

    Kürten, Charlotte; Syrén, Per-Olof

    2016-01-16

    Enzyme catalysis evolved in an aqueous environment. The influence of solvent dynamics on catalysis is, however, currently poorly understood and usually neglected. The study of water dynamics in enzymes and the associated thermodynamical consequences is highly complex and has involved computer simulations, nuclear magnetic resonance (NMR) experiments, and calorimetry. Water tunnels that connect the active site with the surrounding solvent are key to solvent displacement and dynamics. The protocol herein allows for the engineering of these motifs for water transport, which affects specificity, activity and thermodynamics. By providing a biophysical framework founded on theory and experiments, the method presented herein can be used by researchers without previous expertise in computer modeling or biophysical chemistry. The method will advance our understanding of enzyme catalysis on the molecular level by measuring the enthalpic and entropic changes associated with catalysis by enzyme variants with obstructed water tunnels. The protocol can be used for the study of membrane-bound enzymes and other complex systems. This will enhance our understanding of the importance of solvent reorganization in catalysis as well as provide new catalytic strategies in protein design and engineering.

  14. Confined catalysis under two-dimensional materials

    PubMed Central

    Li, Haobo; Xiao, Jianping; Bao, Xinhe

    2017-01-01

    Confined microenvironments formed in heterogeneous catalysts have recently been recognized as equally important as catalytically active sites. Understanding the fundamentals of confined catalysis has become an important topic in heterogeneous catalysis. Well-defined 2D space between a catalyst surface and a 2D material overlayer provides an ideal microenvironment to explore the confined catalysis experimentally and theoretically. Using density functional theory calculations, we reveal that adsorption of atoms and molecules on a Pt(111) surface always has been weakened under monolayer graphene, which is attributed to the geometric constraint and confinement field in the 2D space between the graphene overlayer and the Pt(111) surface. A similar result has been found on Pt(110) and Pt(100) surfaces covered with graphene. The microenvironment created by coating a catalyst surface with 2D material overlayer can be used to modulate surface reactivity, which has been illustrated by optimizing oxygen reduction reaction activity on Pt(111) covered by various 2D materials. We demonstrate a concept of confined catalysis under 2D cover based on a weak van der Waals interaction between 2D material overlayers and underlying catalyst surfaces. PMID:28533413

  15. Electromagnetic field redistribution induced selective plasmon driven surface catalysis in metal nanowire-film systems

    PubMed Central

    Pan, Liang; Huang, Yingzhou; Yang, Yanna; Xiong, Wen; Chen, Guo; Su, Xun; Wei, Hua; Wang, Shuxia; Wen, Weijia

    2015-01-01

    For the novel interpretation of Raman spectrum from molecule at metal surface, the plasmon driven surface catalysis (PDSC) reactions have become an interesting topic in the research field of surface enhanced Raman scattering (SERS). In this work, the selective PDSC reactions of p,p’-dimercaptoazobenzene (DMAB) produced from para-aminothiophenol (PATP) or 4-nitrobenzenethiol (4NBT) were demonstrated in the Ag nanowires dimer-Au film systems. The different SERS spectra collected at individual part and adjacent part of the same nanowire-film system pointed out the importance of the electromagnetic field redistribution induced by image charge on film in this selective surface catalysis, which was confirmed by the simulated electromagnetic simulated electro- magnetic field distributions. Our result indicated this electromagnetic field redistribution induced selective surface catalysis was largely affected by the polarization and wavelength of incident light but slightly by the difference in diameters between two nanowires. Our work provides a further understanding of PDSC reaction in metal nanostructure and could be a deep support for the researches on surface catalysis and surface analysis. PMID:26601698

  16. Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS): Final Technical Report

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

    de Boer, Gijs; Lawrence, Dale; Palo, Scott

    2017-03-29

    This final technical report details activities undertaken as part of the referenced project. Included is information on the preparation of aircraft for deployment to Alaska, summaries of the three deployments covered under this project, and a brief description of the dataset and science directions pursued. Additionally, we provide information on lessons learned, publications, and presentations resulting from this work.

  17. Vocational Curriculum Modification. Teaching Technical Language to Learning Handicapped Students. Project HIRE: A Curriculum Management System for Instructing the Handicapped. Final Report, Volume 1.

    ERIC Educational Resources Information Center

    Gardner, David C.; And Others

    Volume 1 of the final report on Project HIRE reports the design, development, field-testing, and refining of self-instructional packages to teach entry level technical vocabulary to learning handicapped students mainstreamed in vocational programs. Volume 2, a management handbook, reports the methods and findings concerning development of…

  18. Joint Technical Architecture for Robotic Systems (JTARS)-Final Report

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T.; Holloway, Sidney E., III

    2006-01-01

    This document represents the final report for the Joint Technical Architecture for Robotic Systems (JTARS) project, funded by the Office of Exploration as part of the Intramural Call for Proposals of 2005. The project was prematurely terminated, without review, as part of an agency-wide realignment towards the development of a Crew Exploration Vehicle (CEV) and meeting the near-term goals of lunar exploration.

  19. Review of Final Year MSP Evaluations, Performance Period 2007. Analytic and Technical Support for Mathematics and Science Partnerships

    ERIC Educational Resources Information Center

    Bobronnikov, Ellen; Rhodes, Hilary; Bradley, Cay

    2010-01-01

    This final report culminates the evaluation and technical assistance provided for the U.S. Department of Education's Mathematics and Science Partnership (MSP) Program and its projects since 2005. As part of this support, Abt Associates looked across the portfolio of projects funded by the MSP program to draw lessons on best practices. This…

  20. Free Radical Chemistry Enabled by Visible Light-Induced Electron Transfer.

    PubMed

    Staveness, Daryl; Bosque, Irene; Stephenson, Corey R J

    2016-10-18

    Harnessing visible light as the driving force for chemical transformations generally offers a more environmentally friendly alternative compared with classical synthetic methodology. The transition metal-based photocatalysts commonly employed in photoredox catalysis absorb efficiently in the visible spectrum, unlike most organic substrates, allowing for orthogonal excitation. The subsequent excited states are both more reducing and more oxidizing than the ground state catalyst and are competitive with some of the more powerful single-electron oxidants or reductants available to organic chemists yet are simply accessed via irradiation. The benefits of this strategy have proven particularly useful in radical chemistry, a field that traditionally employs rather toxic and hazardous reagents to generate the desired intermediates. In this Account, we discuss our efforts to leverage visible light photoredox catalysis in radical-based bond-forming and bond-cleaving events for which few, if any, environmentally benign alternatives exist. Mechanistic investigations have driven our contributions in this field, for both facilitating desired transformations and offering new, unexpected opportunities. In fact, our total synthesis of (+)-gliocladin C was only possible upon elucidating the propensity for various trialkylamine additives to elicit a dual behavior as both a reductive quencher and a H-atom donor. Importantly, while natural product synthesis was central to our initial motivations to explore these photochemical processes, we have since demonstrated applicability within other subfields of chemistry, and our evaluation of flow technologies demonstrates the potential to translate these results from the bench to pilot scale. Our forays into photoredox catalysis began with fundamental methodology, providing a tin-free reductive dehalogenation that exchanged the gamut of hazardous reagents previously employed for such a transformation for visible light-mediated, ambient temperature conditions. Evolving from this work, a new avenue toward atom transfer radical addition (ATRA) chemistry was developed, enabling dual functionalization of both double and triple bonds. Importantly, we have also expanded our portfolio to target clinically relevant scaffolds. Photoredox catalysis proved effective in generating high value fluorinated alkyl radicals through the use of abundantly available starting materials, providing access to libraries of trifluoromethylated (hetero)arenes as well as intriguing gem-difluoro benzyl motifs via a novel photochemical radical Smiles rearrangement. Finally, we discuss a photochemical strategy toward sustainable lignin processing through selective C-O bond cleavage methodology. The collection of these efforts is meant to highlight the potential for visible light-mediated radical chemistry to impact a variety of industrial sectors.

  1. Search for nucleon decays induced by GUT magnetic monopoles with the MACRO experiment

    NASA Astrophysics Data System (ADS)

    Ambrosio, M.; Antolini, R.; Auriemma, G.; Bakari, D.; Baldini, A.; Barbarino, G. C.; Barish, B. C.; Battistoni, G.; Becherini, Y.; Bellotti, R.; Bemporad, C.; Bernardini, P.; Bilokon, H.; Bloise, C.; Bower, C.; Brigida, M.; Bussino, S.; Cafagna, F.; Calicchio, M.; Campana, D.; Carboni, M.; Caruso, R.; Cecchini, S.; Cei, F.; Chiarella, V.; Choudhary, B. C.; Coutu, S.; Cozzi, M.; de Cataldo, G.; Dekhissi, H.; de Marzo, C.; de Mitri, I.; Derkaoui, J.; de Vincenzi, M.; di Credico, A.; Erriquez, O.; Favuzzi, C.; Forti, C.; Fusco, P.; Giacomelli, G.; Giannini, G.; Giglietto, N.; Giorgini, M.; Grassi, M.; Grillo, A.; Guarino, F.; Gustavino, C.; Habig, A.; Hanson, K.; Heinz, R.; Iarocci, E.; Katsavounidis, E.; Katsavounidis, I.; Kearns, E.; Kim, H.; Kyriazopoulou, S.; Lamanna, E.; Lane, C.; Levin, D. S.; Lipari, P.; Longley, N. P.; Longo, M. J.; Loparco, F.; Maaroufi, F.; Mancarella, G.; Mandrioli, G.; Manzoor, S.; Margiotta, A.; Marini, A.; Martello, D.; Marzari-Chiesa, A.; Mazziotta, M. N.; Michael, D. G.; Monacelli, P.; Montaruli, T.; Monteno, M.; Mufson, S.; Musser, J.; Nicolò, D.; Nolty, R.; Orth, C.; Osteria, G.; Palamara, O.; Patera, V.; Patrizii, L.; Pazzi, R.; Peck, C. W.; Perrone, L.; Petrera, S.; Pistilli, P.; Popa, V.; Rainò, A.; Reynoldson, J.; Ronga, F.; Rrhioua, A.; Satriano, C.; Scapparone, E.; Scholberg, K.; Sciubba, A.; Serra, P.; Sioli, M.; Sirri, G.; Sitta, M.; Spinelli, P.; Spinetti, M.; Spurio, M.; Steinberg, R.; Stone, J. L.; Sulak, L. R.; Surdo, A.; Tarlè, G.; Togo, V.; Vakili, M.; Walter, C. W.; Webb, R.

    2002-12-01

    The interaction of a Grand Unification Magnetic Monopole with a nucleon can lead to a barion-number violating process in which the nucleon decays into a lepton and one or more mesons (catalysis of nucleon decay). In this paper we report an experimental study of the effects of a catalysis process in the MACRO detector. Using a dedicated analysis we obtain new magnetic monopole (MM) flux upper limits at the level of \\char1263\\cdot 10^{-16} cm^{-2} s^{-1} sr^{-1} for 1.1\\cdot 10^{-4} le \\vertβ\\vert le 5\\cdot 10^{-3}, based on the search for catalysis events in the MACRO data. We also analyze the dependence of the MM flux limit on the catalysis cross section.

  2. Cooperative Light-Activated Iodine and Photoredox Catalysis for the Amination of Csp3 -H Bonds.

    PubMed

    Becker, Peter; Duhamel, Thomas; Stein, Christopher J; Reiher, Markus; Muñiz, Kilian

    2017-06-26

    An unprecedented method that makes use of the cooperative interplay between molecular iodine and photoredox catalysis has been developed for dual light-activated intramolecular benzylic C-H amination. Iodine serves as the catalyst for the formation of a new C-N bond by activating a remote Csp3 -H bond (1,5-HAT process) under visible-light irradiation while the organic photoredox catalyst TPT effects the reoxidation of the molecular iodine catalyst. To explain the compatibility of the two involved photochemical steps, the key N-I bond activation was elucidated by computational methods. The new cooperative catalysis has important implications for the combination of non-metallic main-group catalysis with photocatalysis. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  3. Fundamental insights into interfacial catalysis.

    PubMed

    Gong, Jinlong; Bao, Xinhe

    2017-04-03

    Surface and interfacial catalysis plays a vital role in chemical industries, electrochemistry and photochemical reactions. The challenges of modern chemistry are to optimize the chemical reaction processes and understand the detailed mechanism of chemical reactions. Since the early 1960s, the foundation of surface science systems has allowed the study of surface and interfacial phenomena on atomic/molecular level, and thus brought a number of significant developments to fundamental and technological processes, such as catalysis, material science and biochemistry, just to name a few. This themed issue describes the recent advances and developments in the fundamental understanding of surface and interfacial catalysis, encompassing areas of knowledge from metal to metal oxide, carbide, graphene, hexagonal boron nitride, and transition metal dichalcogenides under ultrahigh vacuum conditions, as well as under realistic reaction conditions.

  4. Thermoswitchable catalysis controlled by reversible dispersion/aggregation change of nanoreactors in the presence of α-CD polymers

    NASA Astrophysics Data System (ADS)

    Li, Yinfeng; Hu, Jie; Niu, Chengrong; Leng, Jinghang; Li, Songjun

    2018-06-01

    The present work was aimed at preparing a thermosensitive nanoreactor system which could adjust its dispersion/aggregation status according to external temperature change to achieve the switchable catalysis. The mesoporous silica nanoparticle (MSNP) was selected as the framework material of the nanoreactor, and Ag nanoparticles were encapsulated in the mesoporous silica by an in situ reaction. Dodecyl groups were introduced onto MSNP surface, which could transform reversibly between complexation and disassociation with α-cyclodextrin (CD) cavity upon temperature change. It was found that the nanoreactors aggregated and the catalysis was effectively switched ‘off’ in the presence of CD polymers at low temperature (20 °C). However, when the temperature increased to 50 °C, the nanoreactors redispersed and catalysis successfully switched ‘on’.

  5. Thermoswitchable catalysis controlled by reversible dispersion/aggregation change of nanoreactors in the presence of α-CD polymers.

    PubMed

    Li, Yinfeng; Hu, Jie; Niu, Chengrong; Leng, Jinghang; Li, Songjun

    2018-06-01

    The present work was aimed at preparing a thermosensitive nanoreactor system which could adjust its dispersion/aggregation status according to external temperature change to achieve the switchable catalysis. The mesoporous silica nanoparticle (MSNP) was selected as the framework material of the nanoreactor, and Ag nanoparticles were encapsulated in the mesoporous silica by an in situ reaction. Dodecyl groups were introduced onto MSNP surface, which could transform reversibly between complexation and disassociation with α-cyclodextrin (CD) cavity upon temperature change. It was found that the nanoreactors aggregated and the catalysis was effectively switched 'off' in the presence of CD polymers at low temperature (20 °C). However, when the temperature increased to 50 °C, the nanoreactors redispersed and catalysis successfully switched 'on'.

  6. Pacific Educational Computer Network Study. Final Report.

    ERIC Educational Resources Information Center

    Hawaii Univ., Honolulu. ALOHA System.

    The Pacific Educational Computer Network Feasibility Study examined technical and non-technical aspects of the formation of an international Pacific Area computer network for higher education. The technical study covered the assessment of the feasibility of a packet-switched satellite and radio ground distribution network for data transmission…

  7. Micelle Catalysis of an Aromatic Substitution Reaction

    ERIC Educational Resources Information Center

    Corsaro, Gerald; Smith J. K.

    1976-01-01

    Describes an experiment in which the iodonation of aniline reaction is shown to undergo catalysis in solution of sodium lauryl sulfate which forms micelles with negatively charged pseudo surfaces. (MLH)

  8. Highly Regioselective Indoline Synthesis under Nickel/Photoredox Dual Catalysis.

    PubMed

    Tasker, Sarah Z; Jamison, Timothy F

    2015-08-05

    Nickel/photoredox catalysis is used to synthesize indolines in one step from iodoacetanilides and alkenes. Very high regioselectivity for 3-substituted indoline products is obtained for both aliphatic and styrenyl olefins. Mechanistic investigations indicate that oxidation to Ni(III) is necessary to perform the difficult C-N bond-forming reductive elimination, producing a Ni(I) complex, which in turn is reduced to Ni(0). This process serves to further demonstrate the utility of photoredox catalysts as controlled single electron transfer agents in multioxidation state nickel catalysis.

  9. BIOPHYSICS. Comment on "Extreme electric fields power catalysis in the active site of ketosteroid isomerase".

    PubMed

    Chen, Deliang; Savidge, Tor

    2015-08-28

    Fried et al. (Reports, 19 December 2014, p. 1510) demonstrate electric field-dependent acceleration of biological catalysis using ketosteroid isomerase as a prototypic example. These findings were not extended to aqueous solution because water by itself has field fluctuations that are too large and fast to provide a catalytic effect. Given physiological context, when water electrostatic interactions are considered, electric fields play a less important role in the catalysis. Copyright © 2015, American Association for the Advancement of Science.

  10. One body, many heads; the Cerberus of catalysis. A new multipurpose in-situ cell for XAS at ALBA

    NASA Astrophysics Data System (ADS)

    Guilera, G.; Rey, F.; Hernández-Fenollosa, J.; Cortés-Vergaz, J. J.

    2013-04-01

    A new multi-purpose in-situ cell and its control system have been developed for synchrotron-based techniques as are X-Ray Absorption spectroscopy (XAS) and X-Ray Diffraction (XRD). The cell is made of a stainless steel 'body' and three different exchangeable 'heads' to tackle different scientific areas that include solid-gas catalysis, solid-liquid catalysis and electrocatalysis. The different versions of the cell are herein described and their functionality is exemplified by some case studies.

  11. Recent Advances in Nickel Catalysis

    PubMed Central

    Tasker, Sarah Z.; Standley, Eric A.; Jamison, Timothy F.

    2015-01-01

    Preface The field of nickel catalysis has made tremendous advances in the past decade. There are several key properties of nickel that have allowed for a broad range of innovative reaction development, such as facile oxidative addition and ready access to multiple oxidation states. In recent years, these properties have been increasingly understood and leveraged to perform transformations long considered exceptionally challenging. Herein, we discuss some of the most recent and significant developments in homogeneous nickel catalysis with an emphasis on both synthetic outcome and mechanism. PMID:24828188

  12. Enantioselective α-Alkylation of Aldehydes by Photoredox Organocatalysis: Rapid Access to Pharmacophore Fragments from β-Cyanoaldehydes.

    PubMed

    Welin, Eric R; Warkentin, Alexander A; Conrad, Jay C; MacMillan, David W C

    2015-08-10

    The combination of photoredox catalysis and enamine catalysis has enabled the development of an enantioselective α-cyanoalkylation of aldehydes. This synergistic catalysis protocol allows for the coupling of two highly versatile yet orthogonal functionalities, allowing rapid diversification of the oxonitrile products to a wide array of medicinally relevant derivatives and heterocycles. This methodology has also been applied to the total synthesis of the lignan natural product (-)-bursehernin. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Community College Technical Mathematics Project. Final Report.

    ERIC Educational Resources Information Center

    Self, Samuel L.

    The purpose of the research project was to develop an applied or technical mathematics curriculum which would meet the needs of vocational-technical students at the community college level. The research project was divided into three distinct phases: Identifying the mathematical concepts requisite for job-entry competencies in each of the…

  14. 7 CFR 614.10 - Appeals before the Farm Service Agency county committee.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... section are completed, provide the FSA county committee with a written technical determination in the form... part 780, a participant may appeal a final technical determination or a program decision to the FSA... appeal requests review of the technical determination by the applicable State Conservationist prior to...

  15. 77 FR 47495 - Final Priority; Technical Assistance on State Data Collection, Analysis, and Reporting-National...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-08

    ... intervention and preschool service providers with data on their qualifications, certification, and preparation... Priority; Technical Assistance on State Data Collection, Analysis, and Reporting--National IDEA Technical Assistance Center on Early Childhood Longitudinal Data Systems; Rule #0;#0;Federal Register / Vol. 77, No...

  16. 77 FR 18716 - Transportation Security Administration Postal Zip Code Change; Technical Amendment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... organizational changes and it has no substantive effect on the public. DATES: Effective March 28, 2012. FOR... No. 1572-9] Transportation Security Administration Postal Zip Code Change; Technical Amendment AGENCY: Transportation Security Administration, DHS. ACTION: Final rule. SUMMARY: This rule is a technical change to...

  17. Studying the Cost and Value of Library Services: Final Report. Technical Report APLAB/94-3/1,2,3,4.

    ERIC Educational Resources Information Center

    Kantor, Paul B.; And Others

    This is the final technical report (in three parts) of a 15-month long project to study the costs and value of library functions at five major research libraries. Twenty-one services or service aspects were studied, and numerous measures of the importance or benefit of the service to the users were made. These measures were studied together to lay…

  18. An Inquiry into Testing of Information Retrieval Systems. Comparative Systems Laboratory Final Technical Report, Part III: CSL Related Studies.

    ERIC Educational Resources Information Center

    Zull, Carolyn Gifford, Ed.; And Others

    This third volume of the Comparative Systems Laboratory (CSL) Final Technical Report is a collection of relatively independent studies performed on CSL materials. Covered in this document are studies on: (1) properties of files, including a study of the growth rate of a dictionary of index terms as influenced by number of documents in the file and…

  19. Programs of Study as a State Policy Mandate: A Longitudinal Study of the South Carolina Personal Pathways to Success Initiative. Unabridged Final Technical Report (Years 1-5)

    ERIC Educational Resources Information Center

    Hammond, Cathy; Withington, Cairen; Sharp, Julia L.; Mobley, Catherine; Drew, Sam F.; Stringfield, Samuel C.; Stipanovic, Natalie; Swiger, Caroline M.; Daugherty, Lindsay; Griffith, Cathy

    2014-01-01

    This final report presents findings from data collection and analysis conducted during a five-year study by the National Dropout Prevention Center (NDPC) at Clemson University, in conjunction with colleagues from the National Research Center for Career and Technical Education (NRCCTE) at the University of Louisville. This project was one of three…

  20. Ground-Based Radiometric Measurements of Slant Path Attenuation in the V/W Bands

    DTIC Science & Technology

    2016-04-01

    GROUND-BASED RADIOMETRIC MEASUREMENTS OF SLANT PATH ATTENUATION IN THE V/W BANDS APRIL 2016 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE...2. REPORT TYPE FINAL TECHNICAL REPORT 3. DATES COVERED (From - To) OCT 2012 – SEP 2015 4. TITLE AND SUBTITLE GROUND-BASED RADIOMETRIC MEASUREMENTS ...SUPPLEMENTARY NOTES 14. ABSTRACT Ground-based radiometric techniques were applied to measure the slant path attenuation cumulative distribution function to

  1. Final Technical Progress Report: Development of Low-Cost Suspension Heliostat; December 7, 2011 - December 6, 2012

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

    Bender, W.

    2013-01-01

    Final technical progress report of SunShot Incubator Solaflect Energy. The project succeeded in demonstrating that the Solaflect Suspension Heliostat design is viable for large-scale CSP installations. Canting accuracy is acceptable and is continually improving as Solaflect improves its understanding of this design. Cost reduction initiatives were successful, and there are still many opportunities for further development and further cost reduction.

  2. EDITORIAL: Non-thermal plasma-assisted fuel conversion for green chemistry Non-thermal plasma-assisted fuel conversion for green chemistry

    NASA Astrophysics Data System (ADS)

    Nozaki, Tomohiro; Gutsol, Alexander

    2011-07-01

    This special issue is based on the symposium on Non-thermal Plasma Assisted Fuel Conversion for Green Chemistry, a part of the 240th ACS National Meeting & Exposition held in Boston, MA, USA, 22-26 August 2010. Historically, the Division of Fuel Chemistry of the American Chemical Society (ACS) has featured three plasma-related symposia since 2000, and has launched special issues in Catalysis Today on three occasions: 'Catalyst Preparation using Plasma Technologies', Fall Meeting, Washington DC, USA, 2000. Special issue in Catalysis Today 72 (3-4) with 12 peer-reviewed articles. 'Plasma Technology and Catalysis', Spring Meeting, New Orleans, LA, USA, 2003. Special issue in Catalysis Today 89 (1-2) with more than 30 peer-reviewed articles. 'Utilization of Greenhouse Gases II' (partly focused on plasma-related technologies), Spring Meeting, Anaheim, CA, USA, 2004. Special issue in Catalysis Today 98 (4) with 25 peer-reviewed articles. This time, selected presentations are published in this Journal of Physics D: Applied Physics special issue. An industrial material and energy conversion technology platform is established on thermochemical processes including various catalytic reactions. Existing industry-scale technology is already well established; nevertheless, further improvement in energy efficiency and material saving has been continuously demanded. Drastic reduction of CO2 emission is also drawing keen attention with increasing recognition of energy and environmental issues. Green chemistry is a rapidly growing research field, and frequently highlights renewable bioenergy, bioprocesses, solar photocatalysis of water splitting, and regeneration of CO2 into useful chemicals. We would also like to emphasize 'plasma catalysis' of hydrocarbon resources as an important part of the innovative next-generation green technologies. The peculiarity of non-thermal plasma is that it can generate reactive species almost independently of reaction temperature. Plasma-generated reactive species are used to initiate chemical reactions at unexpectedly lower temperatures than conventional thermochemical reactions, leading to non-equilibrium product distribution or creating unconventional reaction pathways. When non-thermal plasma is combined with catalysts, a synergistic effect is frequently observed. Such unique properties of non-thermal plasma are expected to contribute excellent control over process parameters that meet the need for energy saving, environment protection, and material preservation. This special issue consists of eleven peer-reviewed papers including two invited publications. Professors Alexander Fridman and Alexander Rabinovich from Drexel University, and Dr Gutsol from the Chevron Energy Technology Company present a critical review of various industry-oriented practical plasma fuel conversion processes. Professor Richard Mallinson from University of Oklahoma describes his recent project on E85 (85%-ethanol/15%-gasoline) upgrading using non-thermal plasma and catalyst hybrid reactor, and highlights the synergistic effect on fuel conversion processes. Other papers focus on plasma/catalyst hybrid reactions for methane dry (CO2) reforming, plasma synthesis of carbon suboxide polymer from CO, the gas-to-liquid (GTL) process using a non-thermal plasma-combined micro-chemical reactor, and molecular beam characterization of plasma-generated reactive species. Much research regarding plasma catalysis is ongoing worldwide, but there is plenty of room for further development of plasma fuel processing, which could eventually provide a viable and flexible solution in future energy and material use. Finally, we would like to thank all symposium participants for their active discussion. We appreciate the sponsorship of the Division of Fuel Chemistry of the American Chemical Society. We express special thanks to the program chair of the Fuel Chemistry Division, Professor Chang-jun Liu at Tianjin University, for his dedication to the success of the symposium. We particularly express our appreciation to the Editorial Board of Journal of Physics D: Applied Physics for publication of the special issue.

  3. A Course in Kinetics and Catalysis.

    ERIC Educational Resources Information Center

    Bartholomew, C. H.

    1981-01-01

    Describes a one-semester, three-credit hour course integrating the fundamentals of kinetics and the scientific/engineering principles of heterogeneous catalysis. Includes course outline, list of texts, background readings, and topical journal articles. (SK)

  4. Selective Oxidation and Ammoxidation of Olefins by Heterogeneous Catalysis.

    ERIC Educational Resources Information Center

    Grasselli, Robert K.

    1986-01-01

    Shows how the ammoxidation of olefins can be understood in terms of free radicals and surface bound organometallic intermediates. Also illustrates the close intellectual relationships between heterogeneous catalysis and organometallic chemistry. (JN)

  5. Chiral poly-rare earth metal complexes in asymmetric catalysis

    PubMed Central

    Shibasaki, Masakatsu

    2006-01-01

    Asymmetric catalysis is a powerful component of modern synthetic organic chemistry. To further broaden the scope and utility of asymmetric catalysis, new basic concepts for the design of asymmetric catalysts are crucial. Because most chemical reactions involve bond-formation between two substrates or moieties, high enantioselectivity and catalyst activity should be realized if an asymmetric catalyst can activate two reacting substrates simultaneously at defined positions. Thus, we proposed the concept of bifunctional asymmetric catalysis, which led us to the design of new asymmetric catalysts containing two functionalities (e.g. a Lewis acid and a Brønsted base or a Lewis acid and a Lewis base). These catalysts demonstrated broad reaction applicability with excellent substrate generality. Using our catalytic asymmetric reactions as keys steps, efficient total syntheses of pharmaceuticals and their biologically active lead natural products were achieved. PMID:25792774

  6. Atmospheric pressure reaction cell for operando sum frequency generation spectroscopy of ultrahigh vacuum grown model catalysts

    NASA Astrophysics Data System (ADS)

    Roiaz, Matteo; Pramhaas, Verena; Li, Xia; Rameshan, Christoph; Rupprechter, Günther

    2018-04-01

    A new custom-designed ultrahigh vacuum (UHV) chamber coupled to a UHV and atmospheric-pressure-compatible spectroscopic and catalytic reaction cell is described, which allows us to perform IR-vis sum frequency generation (SFG) vibrational spectroscopy during catalytic (kinetic) measurements. SFG spectroscopy is an exceptional tool to study vibrational properties of surface adsorbates under operando conditions, close to those of technical catalysis. This versatile setup allows performing surface science, SFG spectroscopy, catalysis, and electrochemical investigations on model systems, including single crystals, thin films, and deposited metal nanoparticles, under well-controlled conditions of gas composition, pressure, temperature, and potential. The UHV chamber enables us to prepare the model catalysts and to analyze their surface structure and composition by low energy electron diffraction and Auger electron spectroscopy, respectively. Thereafter, a sample transfer mechanism moves samples under UHV to the spectroscopic cell, avoiding air exposure. In the catalytic cell, SFG spectroscopy and catalytic tests (reactant/product analysis by mass spectrometry or gas chromatography) are performed simultaneously. A dedicated sample manipulation stage allows the model catalysts to be examined from LN2 temperature to 1273 K, with gaseous reactants in a pressure range from UHV to atmospheric. For post-reaction analysis, the SFG cell is rapidly evacuated and samples are transferred back to the UHV chamber. The capabilities of this new setup are demonstrated by benchmark results of CO adsorption on Pt and Pd(111) single crystal surfaces and of CO adsorption and oxidation on a ZrO2 supported Pt nanoparticle model catalyst grown by atomic layer deposition.

  7. Chemical Technology Division annual technical report, 1990

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

    Not Available

    1991-05-01

    Highlights of the Chemical Technology (CMT) Division's activities during 1990 are presented. In this period, CMT conducted research and development in the following areas: (1) electrochemical technology, including advanced batteries and fuel cells; (2) technology for coal- fired magnetohydrodynamics and fluidized-bed combustion; (3) methods for recovery of energy from municipal waste and techniques for treatment of hazardous organic waste; (4) the reaction of nuclear waste glass and spent fuel under conditions expected for a high-level waste repository; (5) processes for separating and recovering transuranic elements from nuclear waste streams, concentrating plutonium solids in pyrochemical residues by aqueous biphase extraction, andmore » treating natural and process waters contaminated by volatile organic compounds; (6) recovery processes for discharged fuel and the uranium blanket in the Integral Fast Reactor (IFR); (7) processes for removal of actinides in spent fuel from commercial water-cooled nuclear reactors and burnup in IFRs; and (8) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also has a program in basic chemistry research in the areas of fluid catalysis for converting small molecules to desired products; materials chemistry for superconducting oxides and associated and ordered solutions at high temperatures; interfacial processes of importance to corrosion science, high-temperature superconductivity, and catalysis; and the geochemical processes responsible for trace-element migration within the earth's crust. The Analytical Chemistry Laboratory in CMT provides a broad range of analytical chemistry support services to the scientific and engineering programs at Argonne National Laboratory (ANL). 66 refs., 69 figs., 6 tabs.« less

  8. Hydrophobic Shielding Drives Catalysis of Hydride Transfer in a Family of F420H2-Dependent Enzymes.

    PubMed

    Mohamed, A Elaaf; Condic-Jurkic, Karmen; Ahmed, F Hafna; Yuan, Peng; O'Mara, Megan L; Jackson, Colin J; Coote, Michelle L

    2016-12-13

    A family of flavin/deazaflavin-dependent oxidoreductases (FDORs) from mycobacteria has been recently characterized and found to play a variety of catalytic roles, including the activation of prodrugs such as the candidate anti-tuberculosis drug pretomanid (PA-824). However, our understanding of the catalytic mechanism used by these enzymes is relatively limited. To address this, we have used a combination of quantum mechanics and molecular dynamics calculations to study the catalytic mechanism of the activation of pretomanid by the deazaflavin-dependent nitroreductase (Ddn) from Mycobacterium tuberculosis. The preferred pathway involves an initial hydride transfer step from the deprotonated cofactor (i.e., F 420 H - ), with subsequent protonation, before a series of spontaneous intramolecular reactions to form the final reactive nitrogen species. The most likely proton source is a hydroxonium ion within the solvent accessible active site. Intriguingly, catalysis of the rate-determining hydride transfer step is aided by three tyrosine residues that form a hydrophobic barrier around the active site that, upon reaction, is then disrupted to allow increased water accessibility to facilitate the subsequent proton transfer step. The catalytic mechanism we propose is consistent with previous experimental observations of the Ddn enzyme and will inform the design of improved prodrugs in the future.

  9. Racemic hemiacetals as oxygen-centered pronucleophiles triggering cascade 1,4-addition/Michael reaction through dynamic kinetic resolution under iminium catalysis. Development and mechanistic insights† †Electronic supplementary information (ESI) available: Detailed experimental procedures and characterization of all new compounds, including copies of NMR spectra and HPLC chromatograms traces, computational details and Cartesian coordinates of all stationary points. CCDC 1525188 (4l), 1525189 (6a) and 1525190 (9a). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc00009j Click here for additional data file. Click here for additional data file.

    PubMed Central

    Orue, Ane; Uria, Uxue; Roca-López, David; Delso, Ignacio; Reyes, Efraím; Carrillo, Luisa

    2017-01-01

    2-Hydroxydihydropyran-5-ones behave as excellent polyfunctional reagents able to react with enals through oxa-Michael/Michael process cascade under the combination of iminium and enamine catalysis. These racemic hemiacetalic compounds are used as unconventional O-pronucleophiles in the initial oxa-Michael reaction, also leading to the formation of a single stereoisomer under a dynamic kinetic resolution (DKR) process. Importantly, by using β-aryl or β-alkyl substituted α,β-unsaturated substrates as initial Michael acceptors either kinetically or thermodynamically controlled diastereoisomers were formed with high stereoselection through the careful selection of the reaction conditions. Finally, a complete experimental and computational study confirmed the initially proposed DKR process during the catalytic oxa-Michael/Michael cascade reaction and also explained the kinetic/thermodynamic pathway operating in each case. PMID:28451356

  10. Crystal engineering, structure–function relationships, and the future of metal–organic frameworks

    DOE PAGES

    Allendorf, Mark D.; Stavila, Vitalie

    2014-10-15

    Metal-Organic Frameworks (MOFs) are a rapidly expanding class of hybrid organic-inorganic materials that can be rationally designed and assembled through crystal engineering. The explosion of interest in this subclass of coordination polymers results from their outstanding properties and myriad possible applications that include traditional uses of microporous materials, such as gas storage, separations, and catalysis, to new realms in biomedicine, electronic devices, and and information storage. The objective of this Highlight article is to provide the reader with a sense of where the field stands after roughly fifteen years of research. Remarkable progress has been made, but the barriers tomore » practical and commercial advances are also illuminated. We discuss the basic elements of MOF assembly and present a conceptual hierarchy of structural elements that assists in understanding how unique properties in these materials can be achieved. Structure-function relationships are then discussed; several are now well understood as a result of the focused efforts of many research groups over the past decade. Prospects for practical applications of MOFs in membranes, catalysis, biomedicine, and as active components in electronic and photonic devices are also discussed. Finally, we list key challenges that, in our view, must be addressed for these materials to realize their full potential in the marketplace.« less

  11. Combining metabolic engineering and biocompatible chemistry for high-yield production of homo-diacetyl and homo-(S,S)-2,3-butanediol.

    PubMed

    Liu, Jianming; Chan, Siu Hung Joshua; Brock-Nannestad, Theis; Chen, Jun; Lee, Sang Yup; Solem, Christian; Jensen, Peter Ruhdal

    2016-07-01

    Biocompatible chemistry is gaining increasing attention because of its potential within biotechnology for expanding the repertoire of biological transformations carried out by enzymes. Here we demonstrate how biocompatible chemistry can be used for synthesizing valuable compounds as well as for linking metabolic pathways to achieve redox balance and rescued growth. By comprehensive rerouting of metabolism, activation of respiration, and finally metal ion catalysis, we successfully managed to convert the homolactic bacterium Lactococcus lactis into a homo-diacetyl producer with high titer (95mM or 8.2g/L) and high yield (87% of the theoretical maximum). Subsequently, the pathway was extended to (S,S)-2,3-butanediol (S-BDO) through efficiently linking two metabolic pathways via chemical catalysis. This resulted in efficient homo-S-BDO production with a titer of 74mM (6.7g/L) S-BDO and a yield of 82%. The diacetyl and S-BDO production rates and yields obtained are the highest ever reported, demonstrating the promising combination of metabolic engineering and biocompatible chemistry as well as the great potential of L. lactis as a new production platform. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  12. Multimodal Study of the Speciations and Activities of Supported Pd Catalysts During the Hydrogenation of Ethylene

    DOE PAGES

    Zhao, Shen; Li, Yuanyuan; Liu, Deyu; ...

    2017-08-07

    In this paper we describe a multimodal exploration of the atomic structure and chemical state of silica-supported palladium nanocluster catalysts during the hydrogenation of ethylene in operando conditions that variously transform the metallic phases between hydride and carbide speciations. The work exploits a microreactor that allows combined multiprobe investigations by high-resolution transmission electron microscopy (HR-TEM), X-ray absorption fine structure (XAFS), and microbeam IR (μ-IR) analyses on the catalyst under operando conditions. The work specifically explores the reaction processes that mediate the interconversion of hydride and carbide phases of the Pd clusters in consequence to changes made in the composition ofmore » the gas-phase reactant feeds, their stability against coarsening, the reversibility of structural/compositional transformations, and the role that oligomeric/waxy byproducts (here forming under hydrogen-limited reactant compositions) might play in modifying activity. The results provide new insights into structural features of the chemistry/mechanisms of Pd catalysis during the selective hydrogenation of acetylene in ethylene—a process simplified here in the use of binary ethylene/hydrogen mixtures. Finally, these explorations, performed in operando conditions, provide new understandings of structure–activity relationships for Pd catalysis in regimes that actively transmute important attributes of electronic and atomic structures.« less

  13. Multimodal Study of the Speciations and Activities of Supported Pd Catalysts During the Hydrogenation of Ethylene

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

    Zhao, Shen; Li, Yuanyuan; Liu, Deyu

    In this paper we describe a multimodal exploration of the atomic structure and chemical state of silica-supported palladium nanocluster catalysts during the hydrogenation of ethylene in operando conditions that variously transform the metallic phases between hydride and carbide speciations. The work exploits a microreactor that allows combined multiprobe investigations by high-resolution transmission electron microscopy (HR-TEM), X-ray absorption fine structure (XAFS), and microbeam IR (μ-IR) analyses on the catalyst under operando conditions. The work specifically explores the reaction processes that mediate the interconversion of hydride and carbide phases of the Pd clusters in consequence to changes made in the composition ofmore » the gas-phase reactant feeds, their stability against coarsening, the reversibility of structural/compositional transformations, and the role that oligomeric/waxy byproducts (here forming under hydrogen-limited reactant compositions) might play in modifying activity. The results provide new insights into structural features of the chemistry/mechanisms of Pd catalysis during the selective hydrogenation of acetylene in ethylene—a process simplified here in the use of binary ethylene/hydrogen mixtures. Finally, these explorations, performed in operando conditions, provide new understandings of structure–activity relationships for Pd catalysis in regimes that actively transmute important attributes of electronic and atomic structures.« less

  14. Advanced Transportation System Studies Technical Area 2 (TA-2) Heavy Lift Launch Vehicle Development Contract. Volume 2; Technical Results

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The purpose of the Advanced Transportation System Studies (ATSS) Technical Area 2 (TA-2) Heavy Lift Launch Vehicle Development contract was to provide advanced launch vehicle concept definition and analysis to assist NASA in the identification of future launch vehicle requirements. Contracted analysis activities included vehicle sizing and performance analysis, subsystem concept definition, propulsion subsystem definition (foreign and domestic), ground operations and facilities analysis, and life cycle cost estimation. This document is Volume 2 of the final report for the contract. It provides documentation of selected technical results from various TA-2 analysis activities, including a detailed narrative description of the SSTO concept assessment results, a user's guide for the associated SSTO sizing tools, an SSTO turnaround assessment report, an executive summary of the ground operations assessments performed during the first year of the contract, a configuration-independent vehicle health management system requirements report, a copy of all major TA-2 contract presentations, a copy of the FLO launch vehicle final report, and references to Pratt & Whitney's TA-2 sponsored final reports regarding the identification of Russian main propulsion technologies.

  15. Technical Evaluation Motor No. 7 (TEM-7)

    NASA Technical Reports Server (NTRS)

    Hughes, Phil

    1991-01-01

    The Technical Evaluation Motor No. 7 (TEM-7) test was a full-scale, full duration static test firing of a high performance motor-configuration solid rocket motor with nozzle vectoring. The final test report documents the procedures, performance, and results of the static test firing of TEM-7. All observations, discussions, conclusions, and recommendations included in the report are complete and final except for the TEM-7 fixed housing unbond investigation. A presentation and discussion of TEM-7 performance, anomalies, and test result concurrence with the objectives outlined in CTP-0107, Rev A, Space Shuttle Technical Evaluation Motor No. 7 (TEM-7) Static Fire Test Plan are included.

  16. Building Stronger State Energy Partnerships with the U.S. Department of Energy

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

    Marks, Kate

    2011-09-30

    This final technical report details the results of total work efforts and progress made from October 2007 – September 2011 under the National Association of State Energy Officials (NASEO) cooperative agreement DE-FC26-07NT43264, Building Stronger State Energy Partnerships with the U.S. Department of Energy. Major topical project areas in this final report include work efforts in the following areas: Energy Assurance and Critical Infrastructure, State and Regional Technical Assistance, Regional Initiative, Regional Coordination and Technical Assistance, and International Activities in China. All required deliverables have been provided to the National Energy Technology Laboratory and DOE program officials.

  17. Final Technical Report of Project DE-FG02-96ER14647

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

    Lundeen, Stephen R.

    This is the final technical report of work completed under DOE support over the period Sept. 1, 1996 until May 31, 2015. The title of the project was "Ion/Excited Atom Collision Studies with a Rydberg Target and a CO2 Laser" from 9/1/96 to 10/31/06, and "Properties of Actinide Ions from Measurements of Rydberg Ion Fine Structure" from 11/1/06 until 5/31/15. The primary technical results were a detailed experimental study of resonant charge transfer between Rydberg atoms and highly-charged ions, and unique measurements of many properties of multiply-charged Thorium ions.

  18. Structural and catalytic effects of an invariant purine substitution in the hammerhead ribozyme: implications for the mechanism of acid–base catalysis

    PubMed Central

    Schultz, Eric P.; Vasquez, Ernesto E.; Scott, William G.

    2014-01-01

    The hammerhead ribozyme catalyzes RNA cleavage via acid–base catalysis. Whether it does so by general acid–base catalysis, in which the RNA itself donates and abstracts protons in the transition state, as is typically assumed, or by specific acid–base catalysis, in which the RNA plays a structural role and proton transfer is mediated by active-site water molecules, is unknown. Previous biochemical and crystallographic experiments implicate an invariant purine in the active site, G12, as the general base. However, G12 may play a structural role consistent with specific base catalysis. To better understand the role of G12 in the mechanism of hammerhead catalysis, a 2.2 Å resolution crystal structure of a hammerhead ribozyme from Schistosoma mansoni with a purine substituted for G12 in the active site of the ribozyme was obtained. Comparison of this structure (PDB entry 3zd4), in which A12 is substituted for G, with three previously determined structures that now serve as important experimental controls, allows the identification of structural perturbations that are owing to the purine substitution itself. Kinetic measurements for G12 purine-substituted schistosomal hammerheads confirm a previously observed dependence of rate on the pK a of the substituted purine; in both cases inosine, which is similar to G in pK a and hydrogen-bonding properties, is unexpectedly inactive. Structural comparisons indicate that this may primarily be owing to the lack of the exocyclic 2-amino group in the G12A and G12I substitutions and its structural effect upon both the nucleotide base and phosphate of A9. The latter involves the perturbation of a previously identified and well characterized metal ion-binding site known to be catalytically important in both minimal and full-length hammerhead ribozyme sequences. The results permit it to be suggested that G12 plays an important role in stabilizing the active-site structure. This result, although not inconsistent with the potential role of G12 as a general base, indicates that an alternative hammerhead cleavage mechanism involving specific base catalysis may instead explain the observed rate dependence upon purine substitutions at G12. The crystallographic results, contrary to previous assumptions, therefore cannot be interpreted to favor the general base catalysis mecahnism over the specific base catalysis mechanism. Instead, both of these mutually exclusive mechanistic alternatives must be considered in light of the current structural and biochemical data. PMID:25195740

  19. Structural and catalytic effects of an invariant purine substitution in the hammerhead ribozyme: implications for the mechanism of acid-base catalysis.

    PubMed

    Schultz, Eric P; Vasquez, Ernesto E; Scott, William G

    2014-09-01

    The hammerhead ribozyme catalyzes RNA cleavage via acid-base catalysis. Whether it does so by general acid-base catalysis, in which the RNA itself donates and abstracts protons in the transition state, as is typically assumed, or by specific acid-base catalysis, in which the RNA plays a structural role and proton transfer is mediated by active-site water molecules, is unknown. Previous biochemical and crystallographic experiments implicate an invariant purine in the active site, G12, as the general base. However, G12 may play a structural role consistent with specific base catalysis. To better understand the role of G12 in the mechanism of hammerhead catalysis, a 2.2 Å resolution crystal structure of a hammerhead ribozyme from Schistosoma mansoni with a purine substituted for G12 in the active site of the ribozyme was obtained. Comparison of this structure (PDB entry 3zd4), in which A12 is substituted for G, with three previously determined structures that now serve as important experimental controls, allows the identification of structural perturbations that are owing to the purine substitution itself. Kinetic measurements for G12 purine-substituted schistosomal hammerheads confirm a previously observed dependence of rate on the pK(a) of the substituted purine; in both cases inosine, which is similar to G in pK(a) and hydrogen-bonding properties, is unexpectedly inactive. Structural comparisons indicate that this may primarily be owing to the lack of the exocyclic 2-amino group in the G12A and G12I substitutions and its structural effect upon both the nucleotide base and phosphate of A9. The latter involves the perturbation of a previously identified and well characterized metal ion-binding site known to be catalytically important in both minimal and full-length hammerhead ribozyme sequences. The results permit it to be suggested that G12 plays an important role in stabilizing the active-site structure. This result, although not inconsistent with the potential role of G12 as a general base, indicates that an alternative hammerhead cleavage mechanism involving specific base catalysis may instead explain the observed rate dependence upon purine substitutions at G12. The crystallographic results, contrary to previous assumptions, therefore cannot be interpreted to favor the general base catalysis mecahnism over the specific base catalysis mechanism. Instead, both of these mutually exclusive mechanistic alternatives must be considered in light of the current structural and biochemical data.

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

    Kayode, Olumide; Wang, Ruiying; Pendlebury, Devon F.

    The molecular basis of enzyme catalytic power and specificity derives from dynamic interactions between enzyme and substrate during catalysis. While considerable effort has been devoted to understanding how conformational dynamics within enzymes affect catalysis, the role of conformational dynamics within protein substrates has not been addressed. Here in this paper, we examine the importance of substrate dynamics in the cleavage of Kunitz-BPTI protease inhibitors by mesotrypsin, finding that the varied conformational dynamics of structurally similar substrates can profoundly impact the rate of catalysis. A 1.4 Å crystal structure of a mesotrypsin-product complex formed with a rapidly cleaved substrate reveals amore » dramatic conformational change in the substrate upon proteolysis. Using long all-atom molecular dynamics simulations of acyl-enzyme intermediates with proteolysis rates spanning three orders of magnitude, we identify global and local dynamic features of substrates on the ns-μs timescale that correlate with enzymatic rates and explain differential susceptibility to proteolysis. By integrating multiple enhanced sampling methods for molecular dynamics, we model a viable conformational pathway between substratelike and product-like states, linking substrate dynamics on the ns-μs timescale with large collective substrate motions on the much slower timescale of catalysis. Our findings implicate substrate flexibility as a critical determinant of catalysis.« less

  1. Homogeneous Molecular Catalysis of Electrochemical Reactions: Catalyst Benchmarking and Optimization Strategies.

    PubMed

    Costentin, Cyrille; Savéant, Jean-Michel

    2017-06-21

    Modern energy challenges currently trigger an intense interest in catalysis of redox reactions-electrochemical and photochemical-particularly those involving small molecules such as water, hydrogen, oxygen, proton, carbon dioxide. A continuously increasing number of molecular catalysts of these reactions, mostly transition metal complexes, have been proposed, rendering necessary procedures for their rational benchmarking and fueling the quest for leading principles that could inspire the design of improved catalysts. The search of "volcano plots" correlating catalysis kinetics to the stability of the key intermediate is a popular approach to the question in catalysis by surface-active sites, with as foremost example the electrochemical reduction of aqueous proton on metal surfaces. We discussed here for the first time, on theoretical and experimental grounds, the pertinence of such an approach in the field of molecular catalysis. This is the occasion to insist on the virtue of careful mechanism assignments. Particular emphasis is put on the interest of expressing the catalysts' intrinsic kinetic properties by means of catalytic Tafel plots, which relate kinetics and overpotential. We also underscore that the principle and strategies put forward for the catalytic activation of the above-mentioned small molecules are general as illustrated by catalytic applications out of this particular field.

  2. Review on the progress in synthesis and application of magnetic carbon nanocomposites.

    PubMed

    Zhu, Maiyong; Diao, Guowang

    2011-07-01

    This review focuses on the synthesis and application of nanostructured composites containing magnetic nanostructures and carbon-based materials. Great progress in fabrication of magnetic carbon nanocomposites has been made by developing methods including filling process, template-based synthesis, chemical vapor deposition, hydrothermal/solvothermal method, pyrolysis procedure, sol-gel process, detonation induced reaction, self-assembly method, etc. The applications of magnetic carbon nanocomposites expanded to a wide range of fields such as environmental treatment, microwave absorption, magnetic recording media, electrochemical sensor, catalysis, separation/recognization of biomolecules and drug delivery are discussed. Finally, some future trends and perspectives in this research area are outlined.

  3. Review on the progress in synthesis and application of magnetic carbon nanocomposites

    NASA Astrophysics Data System (ADS)

    Zhu, Maiyong; Diao, Guowang

    2011-07-01

    This review focuses on the synthesis and application of nanostructured composites containing magnetic nanostructures and carbon-based materials. Great progress in fabrication of magnetic carbon nanocomposites has been made by developing methods including filling process, template-based synthesis, chemical vapor deposition, hydrothermal/solvothermal method, pyrolysis procedure, sol-gel process, detonation induced reaction, self-assembly method, etc. The applications of magnetic carbon nanocomposites expanded to a wide range of fields such as environmental treatment, microwave absorption, magnetic recording media, electrochemical sensor, catalysis, separation/recognization of biomolecules and drug delivery are discussed. Finally, some future trends and perspectives in this research area are outlined.

  4. Stable metal–organic frameworks as a host platform for catalysis and biomimetics

    DOE PAGES

    Qin, Jun-Sheng; Yuan, Shuai; Lollar, Christina; ...

    2018-01-01

    Recent years have witnessed the exploration and synthesis of an increasing number of metal–organic frameworks (MOFs). The utilization of stable MOFs as a platform for catalysis and biomimetics is discussed.

  5. Heterogeneous Catalysis.

    ERIC Educational Resources Information Center

    Miranda, R.

    1989-01-01

    Described is a heterogeneous catalysis course which has elements of materials processing embedded in the classical format of catalytic mechanisms and surface chemistry. A course outline and list of examples of recent review papers written by students are provided. (MVL)

  6. 78 FR 34392 - Guidance for Industry and Food and Drug Administration Staff: Technical Considerations for Pen...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ...] Guidance for Industry and Food and Drug Administration Staff: Technical Considerations for Pen, Jet, and... availability of a final guidance document entitled ``Technical Considerations for Pen, Jet, and Related... developing information to support a marketing application for a pen, jet, or related injector device intended...

  7. Florida Study of Career and Technical Education. Final Report

    ERIC Educational Resources Information Center

    Jacobson, Louis; Mokher, Christine

    2014-01-01

    A key goal of the "Carl D. Perkins Career and Technical Education Act of 2006" ("Perkins IV") is to ensure career and technical education (CTE) programs are widely available for preparing high school and college students for "high skill, high wage, or high demand occupations in current or emerging professions"…

  8. The CAT-ACT Beamline at ANKA: A new high energy X-ray spectroscopy facility for CATalysis and ACTinide research

    NASA Astrophysics Data System (ADS)

    Zimina, A.; Dardenne, K.; Denecke, M. A.; Grunwaldt, J. D.; Huttel, E.; Lichtenberg, H.; Mangold, S.; Pruessmann, T.; Rothe, J.; Steininger, R.; Vitova, T.

    2016-05-01

    A new hard X-ray beamline for CATalysis and ACTinide research has been built at the synchrotron radiation facility ANKA. The beamline design is dedicated to X-ray spectroscopy, including ‘flux hungry’ photon-in/photon-out and correlative techniques with a special infrastructure for radionuclide and catalysis research. The CAT-ACT beamline will help serve the growing need for high flux/hard X-ray spectroscopy in these communities. The design, the first spectra and the current status of this project are reported.

  9. RNA catalysis and the origins of life

    NASA Technical Reports Server (NTRS)

    Orgel, Leslie E.

    1986-01-01

    The role of RNA catalysis in the origins of life is considered in connection with the discovery of riboszymes, which are RNA molecules that catalyze sequence-specific hydrolysis and transesterification reactions of RNA substrates. Due to this discovery, theories positing protein-free replication as preceding the appearance of the genetic code are more plausible. The scope of RNA catalysis in biology and chemistry is discussed, and it is noted that the development of methods to select (or predict) RNA sequences with preassigned catalytic functions would be a major contribution to the study of life's origins.

  10. Aromatic Chlorosulfonylation by Photoredox Catalysis.

    PubMed

    Májek, Michal; Neumeier, Michael; Jacobi von Wangelin, Axel

    2017-01-10

    Visible-light photoredox catalysis enables the efficient synthesis of arenesulfonyl chlorides from anilines. The new protocol involves the convenient in situ preparation of arenediazonium salts (from anilines) and the reactive gases SO 2 and HCl (from aqueous SOCl 2 ). The photocatalytic chlorosulfonylation operates at mild conditions (room temperature, acetonitrile/water) with low catalyst loading. Various functional groups are tolerated (e.g., halides, azides, nitro groups, CF 3 , SF 5 , esters, heteroarenes). Theoretical and experimental studies support a photoredox-catalysis mechanism. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Final Technical Report for Award DESC0011912, "Trimodal Tapping Mode Atomic Force Microscopy: Simultaneous 4D Mapping of Conservative and Dissipative Probe-Sample Interactions of Energy-Relevant Materials”

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

    Solares, Santiago D.

    The final project report covering the period 7/1/14-6/30/17 provides an overview of the technical accomplishments in the areas of (i) fundamental viscoelasticity, (ii) multifrequency atomic force microscopy, and (iii) characterization of energy-relevant materials with atomic force microscopy. A list of publications supported by the project is also provided.

  12. Application of Knowledge-Based Techniques to Tracking Function

    DTIC Science & Technology

    2006-09-01

    38394041 42434445 46474849 505152 53545556 57585960 616263 646566 676869 707172 737475 7677 7879 8081 8283 8485 8687 8889 9091 9293 9495 969798 99100...Knowledge-based applications to adaptive space-time processing. Volume I: Summary”, AFRL-SN-TR-2001-146 Vol. I (of Vol. VI ), Final Technical Report, July...2001-146 Vol. IV (of Vol. VI ), Final Technical Report, July 2001. [53] C. Morgan, L. Moyer, “Knowledge-based applications to adaptive space-time

  13. Forecasting the Future Food Service World of Work. Final Report. Volume III. Technical Papers on the Future of the Food Service Industry. Service Management Reports.

    ERIC Educational Resources Information Center

    Powers, Thomas F., Ed.; Swinton, John R., Ed.

    This third and final volume of a study on the future of the food service industry contains the technical papers on which the information in the previous two volumes was based. The papers were written by various members of the Pennsylvania State University departments of economics, food science, nutrition, social psychology, and engineering and by…

  14. Final Technical Report for contract number DE-FG02-05ER15670

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

    Glazebrook, Jane

    This is the final technical report for contract number DE-FG02-05ER15670. The project is now complete, and results of the project have been published. Two papers were published based on work done in the last three-year funding period. The DOIs of these papers are included below. The abstracts of the papers, providing summaries of the work, are included in the body of the report.

  15. Astrobee Periodic Technical Review (PTR) Delta 3

    NASA Technical Reports Server (NTRS)

    Provencher, Christopher; Smith, Marion F.; Smith, Ernest Everett; Bualat, Maria Gabriele; Barlow, Jonathan Spencer

    2017-01-01

    Astrobee is a free flying robot for the inside of the International Space Station (ISS). The Periodic Technical Review (PTR) delta 3 is the final design review of the system presented to stakeholders.

  16. Polar source analysis : technical memorandum

    DOT National Transportation Integrated Search

    2017-09-29

    The following technical memorandum describes the development, testing and analysis of various polar source data sets. The memorandum also includes recommendation for potential inclusion in future releases of AEDT. This memorandum is the final deliver...

  17. 2005 v4.2 Technical Support Document

    EPA Pesticide Factsheets

    Technical Support Document for the Final Transport Rule describes how updated 2005 NEI, version 2 emissions and were processed for air quality modeling in support of the Cross-state Air Pollution Rule (CSAPR).

  18. Direct Final Rule for Technical Amendments for Marine Spark-Ignition Engines and Vessels

    EPA Pesticide Factsheets

    Rule published September 16, 2010 to make technical amendments to the design standard for portable marine fuel tanks. This rule incorporates safe recommended practices, developed through industry consensus.

  19. Chemical Technology Division, Annual technical report, 1991

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

    Not Available

    1992-03-01

    Highlights of the Chemical Technology (CMT) Division's activities during 1991 are presented. In this period, CMT conducted research and development in the following areas: (1) electrochemical technology, including advanced batteries and fuel cells; (2) technology for fluidized-bed combustion and coal-fired magnetohydrodynamics; (3) methods for treatment of hazardous and mixed hazardous/radioactive waste; (4) the reaction of nuclear waste glass and spent fuel under conditions expected for an unsaturated repository; (5) processes for separating and recovering transuranic elements from nuclear waste streams; (6) recovery processes for discharged fuel and the uranium blanket in the Integral Fast Reactor (IFR); (7) processes for removalmore » of actinides in spent fuel from commercial water-cooled nuclear reactors and burnup in IFRs; and (8) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also conducts basic research in catalytic chemistry associated with molecular energy resources; chemistry of superconducting oxides and other materials of interest with technological application; interfacial processes of importance to corrosion science, catalysis, and high-temperature superconductivity; and the geochemical processes involved in water-rock interactions occurring in active hydrothermal systems. In addition, the Analytical Chemistry Laboratory in CMT provides a broad range of analytical chemistry support services to the technical programs at Argonne National Laboratory (ANL).« less

  20. Chemical Technology Division, Annual technical report, 1991

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

    Not Available

    1992-03-01

    Highlights of the Chemical Technology (CMT) Division`s activities during 1991 are presented. In this period, CMT conducted research and development in the following areas: (1) electrochemical technology, including advanced batteries and fuel cells; (2) technology for fluidized-bed combustion and coal-fired magnetohydrodynamics; (3) methods for treatment of hazardous and mixed hazardous/radioactive waste; (4) the reaction of nuclear waste glass and spent fuel under conditions expected for an unsaturated repository; (5) processes for separating and recovering transuranic elements from nuclear waste streams; (6) recovery processes for discharged fuel and the uranium blanket in the Integral Fast Reactor (IFR); (7) processes for removalmore » of actinides in spent fuel from commercial water-cooled nuclear reactors and burnup in IFRs; and (8) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also conducts basic research in catalytic chemistry associated with molecular energy resources; chemistry of superconducting oxides and other materials of interest with technological application; interfacial processes of importance to corrosion science, catalysis, and high-temperature superconductivity; and the geochemical processes involved in water-rock interactions occurring in active hydrothermal systems. In addition, the Analytical Chemistry Laboratory in CMT provides a broad range of analytical chemistry support services to the technical programs at Argonne National Laboratory (ANL).« less

  1. Nanostructured Membranes for Enzyme Catalysis and Green Synthesis of Nanoparticles

    EPA Science Inventory

    Macroporous membranes functionalized with ionizable macromolecules provide promising applications in toxic metal capture at high capacity, nanoparticle synthesis, and catalysis. Our low-pressure membrane approach is marked by reaction and separation selectivity and their tunabil...

  2. Nanostructured Membranes for Green Synthesis of Nanoparticles and Enzyme Catalysis

    EPA Science Inventory

    Macroporous membranes functionalized with ionizable macromolecules provide promising applications in toxic metal capture at high capacity, nanoparticle synthesis, and catalysis. Our low‐pressure membrane approach is marked by reaction and separation selectivity and their tunabili...

  3. Single-layer graphdiyne-covered Pt(111) surface: improved catalysis confined under two-dimensional overlayer

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Lin, Zheng-Zhe

    2018-05-01

    In recent years, two-dimensional confined catalysis, i.e., the enhanced catalytic reactions in confined space between metal surface and two-dimensional overlayer, makes a hit and opens up a new way to enhance the performance of catalysts. In this work, graphdiyne overlayer was proposed as a more excellent material than graphene or hexagonal boron nitride for two-dimensional confined catalysis on Pt(111) surface. Density functional theory calculations revealed the superiority of graphdiyne overlayer originates from the steric hindrance effect which increases the catalytic ability and lowers the reaction barriers. Moreover, with the big triangle holes as natural gas tunnels, graphdiyne possesses higher efficiency for the transit of gaseous reactants and products than graphene or hexagonal boron nitride. The results in this work would benefit future development of two-dimensional confined catalysis. [Figure not available: see fulltext.

  4. Orthogonal tandem catalysis

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

    Lohr, Tracy L.; Marks, Tobin J.

    2015-05-20

    Tandem catalysis is a growing field that is beginning to yield important scientific and technological advances toward new and more efficient catalytic processes. 'One-pot' tandem reactions, where multiple catalysts and reagents, combined in a single reaction vessel undergo a sequence of precisely staged catalytic steps, are highly attractive from the standpoint of reducing both waste and time. Orthogonal tandem catalysis is a subset of one-pot reactions in which more than one catalyst is used to promote two or more mechanistically distinct reaction steps. This Perspective summarizes and analyses some of the recent developments and successes in orthogonal tandem catalysis, withmore » particular focus on recent strategies to address catalyst incompatibility. We also highlight the concept of thermodynamic leveraging by coupling multiple catalyst cycles to effect challenging transformations not observed in single-step processes, and to encourage application of this technique to energetically unfavourable or demanding reactions.« less

  5. Molecular catalysis science: Perspective on unifying the fields of catalysis.

    PubMed

    Ye, Rong; Hurlburt, Tyler J; Sabyrov, Kairat; Alayoglu, Selim; Somorjai, Gabor A

    2016-05-10

    Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nanoparticles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sum-frequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. It was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and heterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis.

  6. Molecular catalysis science: Perspective on unifying the fields of catalysis

    PubMed Central

    Ye, Rong; Hurlburt, Tyler J.; Sabyrov, Kairat; Alayoglu, Selim; Somorjai, Gabor A.

    2016-01-01

    Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nanoparticles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sum-frequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. It was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and heterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis. PMID:27114536

  7. Charge-tagged ligands: useful tools for immobilising complexes and detecting reaction species during catalysis

    PubMed Central

    Limberger, Jones; Leal, Bárbara C.; Monteiro, Adriano L.

    2015-01-01

    In recent years, charge-tagged ligands (CTLs) have become valuable tools in organometallic catalysis. Insertion of an ionic side chain into the molecular skeleton of a known ligand has become a useful protocol for anchoring ligands, and consequently catalysts, in polar and ionic liquid phases. In addition, the insertion of a cationic moiety into a ligand is a powerful tool that can be used to detect reaction intermediates in organometallic catalysis through electrospray ionisation mass spectrometry (ESI-MS) experiments. The insertion of an ionic tag ensures the charge in the intermediates independently of the ESI-MS. For this reason, these ligands have been used as ionic probes in mechanistic studies for several catalytic reactions. Here, we summarise selected examples on the use of CTLs as immobilising agents in organometallic catalysis and as probes for studying mechanisms through ESI-MS. PMID:28553458

  8. Probing eudesmane cation-π interactions in catalysis by aristolochene synthase with non-canonical amino acids.

    PubMed

    Faraldos, Juan A; Antonczak, Alicja K; González, Verónica; Fullerton, Rebecca; Tippmann, Eric M; Allemann, Rudolf K

    2011-09-07

    Stabilization of the reaction intermediate eudesmane cation (3) through interaction with Trp 334 during catalysis by aristolochene synthase from Penicillium roqueforti was investigated by site-directed incorporation of proteinogenic and non-canonical aromatic amino acids. The amount of germacrene A (2) generated by the mutant enzymes served as a measure of the stabilization of 3. 2 is a neutral intermediate, from which 3 is formed during PR-AS catalysis by protonation of the C6,C7 double bond. The replacement of Trp 334 with para-substituted phenylalanines of increasing electron-withdrawing properties led to a progressive accumulation of 2 that showed a good correlation with the interaction energies of simple cations such as Na(+) with substituted benzenes. These results provide compelling evidence for the stabilizing role played by Trp 334 in aristolochene synthase catalysis for the energetically demanding transformation of 2 to 3.

  9. Inverse magnetic catalysis from improved holographic QCD in the Veneziano limit

    NASA Astrophysics Data System (ADS)

    Gürsoy, Umut; Iatrakis, Ioannis; Järvinen, Matti; Nijs, Govert

    2017-03-01

    We study the dependence of the chiral condensate on external magnetic field in the context of holographic QCD at large number of flavors. We consider a holographic QCD model where the flavor degrees of freedom fully backreact on the color dynamics. Perturbative QCD calculations have shown that B acts constructively on the chiral condensate, a phenomenon called "magnetic catalysis". In contrast, recent lattice calculations show that, depending on the number of flavors and temperature, the magnetic field may also act destructively, which is called "inverse magnetic catalysis". Here we show that the holographic theory is capable of both behaviors depending on the choice of parameters. For reasonable choice of the potentials entering the model we find qualitative agreement with the lattice expectations. Our results provide insight for the physical reasons behind the inverse magnetic catalysis. In particular, we argue that the backreaction of the flavors to the background geometry decatalyzes the condensate.

  10. Macrocyclic Receptor for Precious Gold, Platinum, or Palladium Coordination Complexes.

    PubMed

    Liu, Wenqi; Oliver, Allen G; Smith, Bradley D

    2018-06-06

    Two macrocyclic tetralactam receptors are shown to selectively encapsulate anionic, square-planar chloride and bromide coordination complexes of gold(III), platinum(II), and palladium(II). Both receptors have a preorganized structure that is complementary to its precious metal guest. The receptors do not directly ligate the guest metal center but instead provide an array of arene π-electron donors that interact with the electropositive metal and hydrogen-bond donors that interact with the outer electronegative ligands. This unique mode of supramolecular recognition is illustrated by six X-ray crystal structures showing receptor encapsulation of AuCl 4 - , AuBr 4 - , PtCl 4 -2 , or Pd 2 Cl 6 -2 . In organic solution, the 1:1 association constants correlate with specific supramolecular features identified in the solid state. Technical applications using these receptors are envisioned in a wide range of fields that involve precious metals, including mining, recycling, catalysis, nanoscience, and medicine.

  11. Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

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

    Rinaldi, Roberto; Jastrzebski, Robin; Clough, Matthew T.

    2016-06-17

    Lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine-tuning of multiple “upstream” (i.e., lignin bioengineering, lignin isolation and “early-stage catalytic conversion of lignin”) and “downstream” (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a “beginning-to-end” analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on the improved understanding ofmore » ligninÏs biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance.« less

  12. Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

    DOE PAGES

    Rinaldi, Roberto; Jastrzebski, Robin; Clough, Matthew T.; ...

    2016-06-17

    In this study, lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine-tuning of multiple “upstream” (i.e., lignin bioengineering, lignin isolation and “early-stage catalytic conversion of lignin”) and “downstream” (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a “beginning-to-end” analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on themore » improved understanding of ligninÏs biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance.« less

  13. Kinetics in the real world: linking molecules, processes, and systems.

    PubMed

    Kohse-Höinghaus, Katharina; Troe, Jürgen; Grabow, Jens-Uwe; Olzmann, Matthias; Friedrichs, Gernot; Hungenberg, Klaus-Dieter

    2018-04-25

    Unravelling elementary steps, reaction pathways, and kinetic mechanisms is key to understanding the behaviour of many real-world chemical systems that span from the troposphere or even interstellar media to engines and process reactors. Recent work in chemical kinetics provides detailed information on the reactive changes occurring in chemical systems, often on the atomic or molecular scale. The optimisation of practical processes, for instance in combustion, catalysis, battery technology, polymerisation, and nanoparticle production, can profit from a sound knowledge of the underlying fundamental chemical kinetics. Reaction mechanisms can combine information gained from theory and experiments to enable the predictive simulation and optimisation of the crucial process variables and influences on the system's behaviour that may be exploited for both monitoring and control. Chemical kinetics, as one of the pillars of Physical Chemistry, thus contributes importantly to understanding and describing natural environments and technical processes and is becoming increasingly relevant for interactions in and with the real world.

  14. Terminally Truncated Isopenicillin N Synthase Generates a Dithioester Product: Evidence for a Thioaldehyde Intermediate during Catalysis and a New Mode of Reaction for Non‐Heme Iron Oxidases

    PubMed Central

    McNeill, Luke A.; Brown, Toby J. N.; Sami, Malkit; Clifton, Ian J.; Burzlaff, Nicolai I.; Claridge, Timothy D. W.; Adlington, Robert M.; Baldwin, Jack E.

    2017-01-01

    Abstract Isopenicillin N synthase (IPNS) catalyses the four‐electron oxidation of a tripeptide, l‐δ‐(α‐aminoadipoyl)‐l‐cysteinyl‐d‐valine (ACV), to give isopenicillin N (IPN), the first‐formed β‐lactam in penicillin and cephalosporin biosynthesis. IPNS catalysis is dependent upon an iron(II) cofactor and oxygen as a co‐substrate. In the absence of substrate, the carbonyl oxygen of the side‐chain amide of the penultimate residue, Gln330, co‐ordinates to the active‐site metal iron. Substrate binding ablates the interaction between Gln330 and the metal, triggering rearrangement of seven C‐terminal residues, which move to take up a conformation that extends the final α‐helix and encloses ACV in the active site. Mutagenesis studies are reported, which probe the role of the C‐terminal and other aspects of the substrate binding pocket in IPNS. The hydrophobic nature of amino acid side‐chains around the ACV binding pocket is important in catalysis. Deletion of seven C‐terminal residues exposes the active site and leads to formation of a new type of thiol oxidation product. The isolated product is shown by LC‐MS and NMR analyses to be the ene‐thiol tautomer of a dithioester, made up from two molecules of ACV linked between the thiol sulfur of one tripeptide and the oxidised cysteinyl β‐carbon of the other. A mechanism for its formation is proposed, supported by an X‐ray crystal structure, which shows the substrate ACV bound at the active site, its cysteinyl β‐carbon exposed to attack by a second molecule of substrate, adjacent. Formation of this product constitutes a new mode of reaction for IPNS and non‐heme iron oxidases in general. PMID:28703303

  15. Terminally Truncated Isopenicillin N Synthase Generates a Dithioester Product: Evidence for a Thioaldehyde Intermediate during Catalysis and a New Mode of Reaction for Non-Heme Iron Oxidases.

    PubMed

    McNeill, Luke A; Brown, Toby J N; Sami, Malkit; Clifton, Ian J; Burzlaff, Nicolai I; Claridge, Timothy D W; Adlington, Robert M; Baldwin, Jack E; Rutledge, Peter J; Schofield, Christopher J

    2017-09-18

    Isopenicillin N synthase (IPNS) catalyses the four-electron oxidation of a tripeptide, l-δ-(α-aminoadipoyl)-l-cysteinyl-d-valine (ACV), to give isopenicillin N (IPN), the first-formed β-lactam in penicillin and cephalosporin biosynthesis. IPNS catalysis is dependent upon an iron(II) cofactor and oxygen as a co-substrate. In the absence of substrate, the carbonyl oxygen of the side-chain amide of the penultimate residue, Gln330, co-ordinates to the active-site metal iron. Substrate binding ablates the interaction between Gln330 and the metal, triggering rearrangement of seven C-terminal residues, which move to take up a conformation that extends the final α-helix and encloses ACV in the active site. Mutagenesis studies are reported, which probe the role of the C-terminal and other aspects of the substrate binding pocket in IPNS. The hydrophobic nature of amino acid side-chains around the ACV binding pocket is important in catalysis. Deletion of seven C-terminal residues exposes the active site and leads to formation of a new type of thiol oxidation product. The isolated product is shown by LC-MS and NMR analyses to be the ene-thiol tautomer of a dithioester, made up from two molecules of ACV linked between the thiol sulfur of one tripeptide and the oxidised cysteinyl β-carbon of the other. A mechanism for its formation is proposed, supported by an X-ray crystal structure, which shows the substrate ACV bound at the active site, its cysteinyl β-carbon exposed to attack by a second molecule of substrate, adjacent. Formation of this product constitutes a new mode of reaction for IPNS and non-heme iron oxidases in general. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  16. Reactivity, characterization, equilibrium thermodynamics and hetero-bimetallic studies of tridentate and tetradentate complexes relevant to syngas catalysis

    NASA Astrophysics Data System (ADS)

    Imler, Gregory H.

    The unifying objective of this work is the study of model systems that will assist in the development of new metal catalysts capable of converting carbon monoxide and hydrogen (syngas) into organic oxygenates at mild temperature and pressure. The selective catalytic transformation of carbon monoxide and hydrogen to liquid fuels and chemical feedstocks represents a major "Grand Challenge" of catalysis science. A core objective is the study of a macrocycle that is related to a porphyrin ligand in order to circumvent some of the disadvantages of utilizing porphyrins in catalysis. The rhodium complex of the macrocycle dibenzotetramethylaza[14]annulene ([(tmtaa)Rh]2]) was reacted with a series of small molecules relevant to CO reduction and hydrogenation. Several complexes were formed that demonstrated the ability to partially reduce and hydrogenate carbon monoxide, including the dirhodium ketone (Rh-C(O)-Rh) and an example of a thermodynamically favorable metal formyl complex ((tmtaa)Rh-C(O)H). An important feature of this work is the measurement of thermodynamic data to provide experimental benchmarks for obtaining key species in CO reduction and hydrogenation. A thorough study of the (tmtaa)Rh system will help in identifying structural features that assist or hinder CO hydrogenation. All reactions are monitored by 1H NMR which permits determination of solution thermodynamics from equilibrium constants obtained by NMR peak integrations. DFT calculations have supplemented experimental results by providing estimates to compare with the experimentally determined thermodynamic data. These computations also provide insight into the structures and thermodynamics of species that cannot be observed directly such as short lived intermediates and thermodynamically unfavorable products. Heterobimetallic complexes of (tmtaa)Rh• with a second metal radical have been utilized to attempt to convert CO to organic products. Reactivity with CO and H2 has been accomplished, with most of these metal systems providing (tmtaa)Rh-C(O)H and M-H as final products. These systems are now ideally set up for catalysis in which M-H can deliver hydrogen to reduce and hydrogenate the rhodium formyl unit. Performing these reactions at high pressures of CO/H2 or with a more sterically hindered analog of tmtaa may provide the conditions necessary for catalysis. Reactivity, thermodynamic and computational studies have been used to analyze and compare bond energies in this current work with previous studies accomplished in the Wayland group. These comparisons permit further understanding into the factors that control bond strength, guiding future studies and allowing tuning of bond strengths based on choice of conditions for a catalytic process. This research has resulted in a more complete understanding of the factors that control the favorability of various intermediates in CO reduction and hydrogenation and the application of these results can be used to guide the next generation of metal ligand systems that will yield organic oxygenates at mild conditions.

  17. Nanobubbles: An Effective Way to Study Gas-Generating Catalysis on a Single Nanoparticle.

    PubMed

    Li, Shuping; Du, Ying; He, Ting; Shen, Yangbin; Bai, Chuang; Ning, Fandi; Hu, Xin; Wang, Wenhui; Xi, Shaobo; Zhou, Xiaochun

    2017-10-11

    Gas-generating catalysis is important to many energy-related research fields, such as photocatalytic water splitting, water electrolysis, etc. The technique of single-nanoparticle catalysis is an effective way to search for highly active nanocatalysts and elucidate the reaction mechanism. However, gas-generating catalysis remains difficult to investigate at the single-nanoparticle level because product gases, such as H 2 and O 2 , are difficult to detect on an individual nanoparticle. Here, we successfully find that nanobubbles can be used to study the gas-generating catalysis, i.e., H 2 generation from formic acid dehydrogenation on a single Pd-Ag nanoplate, with a high time resolution (50 ms) via dark-field microscopy. The research reveals that the nanobubble evolution process includes nucleation time and lifetime. The nucleation rate of nanobubbles is proportional to the catalytic activity of a single nanocatalyst. The relationship between the catalytic activity and the nucleation rate is quantitatively described by a mathematical model, which shows that an onset reaction rate (r onset ) exists for the generation of nanobubbles on a single Pd-Ag nanoplate. The research also reveals that a Pd-Ag nanoplate with larger size usually has a higher activity. However, some large-sized ones still have low activities, indicating the size of the Pd-Ag nanoplate is not the only key factor for the activity. Notablely, further research shows that Pd content is the key factor for the activity of single Pd-Ag nanoplates with similar size. The methodology and knowledge acquired from this research are also applicable to other important gas-generating catalysis reactions at the single-nanoparticle level.

  18. A Course in Heterogeneous Catalysis: Principles, Practice, and Modern Experimental Techniques.

    ERIC Educational Resources Information Center

    Wolf, Eduardo E.

    1981-01-01

    Outlines a multidisciplinary course which comprises fundamental, practical, and experimental aspects of heterogeneous catalysis. The course structure is a combination of lectures and demonstrations dealing with the use of spectroscopic techniques for surface analysis. (SK)

  19. Sustainable Catalysis_Energy efficient reactions and Applications

    EPA Science Inventory

    This book chapter discusses various catalysts for environmental remediation. Detailed information on catalysis using ferrate and ferrite oxidation, TiO2 photocatalysis, and new catalysts (i.e., graphene, perovskites and graphitic carbon nitride) is provided for the degradation of...

  20. Binding Energy and Enzymatic Catalysis.

    ERIC Educational Resources Information Center

    Hansen, David E.; Raines, Ronald T.

    1990-01-01

    Discussed is the fundamental role that the favorable free energy of binding of the rate-determining transition state plays in catalysis. The principle that all of the catalytic factors discussed are realized by the use of this binding energy is reviewed. (CW)

  1. GREEN CHEMICAL SYNTHESIS THROUGH CATALYSIS AND ALTERNATE REACTION CONDITIONS

    EPA Science Inventory

    Green chemical synthesis through catalysis and alternate reaction conditions

    Encompassing green chemistry techniques and methodologies, we have initiated several projects at the National Risk Management Research laboratory that focus on the design and development of chemic...

  2. Seattle To Portland Inter-City ITS Corridor Study And Communications Plan, Final Report

    DOT National Transportation Integrated Search

    1996-03-01

    THIS DOCUMENT IS THE FINAL REPORT PRESENTING THE SEATTLE TO PORTLAND INTELLIGENT TRANSPORTATION SYSTEM (ITS) EARLY DEPLOYMENT PLAN. THE FINAL REPORT SYNTHESIZES INFORMATION FROM TECHNICAL MEMORANDUMS 1 THROUGH 5; INCLUDING EXISTING AND FUTURE CONDITI...

  3. Benchmark Analysis of Career and Technical Education in Lenawee County. Final Report.

    ERIC Educational Resources Information Center

    Hollenbeck, Kevin

    The career and technical education (CTE) provided in grades K-12 in the county's vocational-technical center and 12 local public school districts of Lenawee County, Michigan, was benchmarked with respect to its attention to career development. Data were collected from the following sources: structured interviews with a number of key respondents…

  4. International Project on Technical and Vocational Education (UNEVOC). International Advisory Committee (Third Session, Paris, France, October 2-4, 1995). Final Report = Projet International pour l'Enseignement Technique et Professionnel (UNEVOC). Comite Consultatif International (Troisieme Session, Paris, France, 2-4 octobre 1995). Rapport Final.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    The international advisory committee of the International Project on Technical and Vocational Education (UNEVOC) held its third session in Paris in October 1995. Advisory committee members and observers from the United Nations' specialized, intergovernmental, and nongovernmental organizations reviewed the major UNEVOC project activities undertaken…

  5. International Project on Technical and Vocational Education (UNEVOC). International Advisory Committee (Second Session, Paris, France, December 12-14, 1994). Final Report = Projet International pour l'Enseignement Technique et Professionnel (UNEVOC). Comite Consultatif International (Deuxieme Session, Paris, France, 12-14 decembre 1994). Rapport Final.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    The international advisory committee of the International Project on Technical and Vocational Education (UNEVOC) held its second session in Paris in December 1994. Nine advisory committee members and observers from the United Nations' specialized, intergovernmental, and nongovernmental organizations reviewed the major UNEVOC project activities…

  6. Final Technical Report for ARRA Funding

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

    Rusack, Roger; Mans, Jeremiah; Poling, Ronald

    Final technical report of the University of Minnesota experimental high energy physics group for ARRA support. The Cryogenic Dark Matter Experiment (CDMS) used the funds received to construct a new passive shield to protect a high-purity germanium detector located in the Soudan mine in Northern Minnesota from cosmic rays. The BESIII and the CMS groups purchased computing hardware to assemble computer farms for data analysis and to generate large volumes of simulated data for comparison with the data collected.

  7. Making a Difference in the Lives of Infants and Toddlers and Their Families: The Impacts of Early Head Start. Volumes I-III: Final Technical Report [and] Appendixes [and] Local Contributions to Understanding the Programs and Their Impacts.

    ERIC Educational Resources Information Center

    Love, John M.; Kisker, Ellen Eliason; Ross, Christine M.; Schochet, Peter Z.; Brooks-Gunn, Jeanne; Paulsell, Diane; Boller, Kimberly; Constantine, Jill; Vogel, Cheri; Fuligni, Alison Sidle; Brady-Smith, Christy

    Early Head Start was designed in 1994 as a 2-generation program to enhance children's development and health, strengthen family and community partnerships, and support the staff delivering new services to low-income families with pregnant women, infants, or toddlers. This document contains the final technical report, appendixes, and local…

  8. International Project on Technical and Vocational Education (UNEVOC). International Advisory Committee (First Session, Berlin, Germany, September 20-22, 1993). Final Report = Projet International pour l'Enseignement Technique et Professionnel (UNEVOC). Comite Consultatif International (Premiere Session, Berlin, Germany, 20-22 septembre 1993). Rapport Final.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    The international advisory committee of the International Project on Technical and Vocational Education (UNEVOC) held its first session in Berlin in September 1993. The advisory committee's 10 members and observers from the United Nations' specialized, intergovernmental, and nongovernmental organizations discussed educational policy, links between…

  9. Catalysis Science Initiative: Catalyst Design by Discovery Informatics

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

    Delgass, William Nicholas; Abu-Omar, Mahdi; Caruthers, James

    Catalysts selectively enhance the rates of chemical reactions toward desired products. Such reactions provide great benefit to society in major commercial sectors such as energy production, protecting the environment, and polymer products and thereby contribute heavily to the country’s gross national product. Our premise is that the level of fundamental understanding of catalytic events at the atomic and molecular scale has reached the point that more predictive methods can be developed to shorten the cycle time to new processes. The field of catalysis can be divided into two regimes: heterogeneous and homogeneous. For the heterogeneous catalysis regime, we have usedmore » the water-gas shift (WGS) reaction (CO + H2O + CO2 + H2O) over supported metals as a test bed. Detailed analysis and strong coupling of theory with experiment have led to the following conclusions: • The sequence of elementary steps goes through a COOH intermediate • The CO binding energy is a strong function of coverage of CO adsorbed on the surface in many systems • In the case of Au catalysts, the CO adsorption is generally too weak on surface with close atomic packing, but the enhanced binding at corner atoms (which are missing bonding partners) of cubo-octahedral nanoparticles increases the energy to a near optimal value and produces very active catalysts. • Reaction on the metal alone cannot account for the experimental results. The reaction is dual functional with water activation occurring at the metal-support interface. It is clear from our work that the theory component is essential, not only for prediction of new systems, but also for reconciling data and testing hypotheses regarding potential descriptors. Particularly important is the finding that the interface between nano-sized metal particles and the oxides that are used to support them represent a new state of matter in the sense that the interfacial bonding perturbs the chemical state of both metals atoms and the support atoms in the interfacial region. Some of the first theoretical descriptions of this important chemistry and potential new source of control of catalyst properties are be in preparation for submission. On the homogeneous catalysis side, we have used single site olefin polymerization as the testbed. This system is important because changes in a single ligand bonded to the catalytically active metal site can alter the rates of individual steps in the polymerization sequence and thereby change the properties of the resulting polymer, potentially improving its value in a hundred million pound per year industry. We have made a major advance in understanding such systems by developing a population balance kinetic model that allows us to predict the molecular weight distribution (MWD) of the product. That, in turn, allows use of MWD data to fit kinetic parameters. By combining monomer loss data, MWD, measurement of the number of working active sites, and polymer end group analysis, we have a rich data set that is highly discriminating of kinetic mechanism. Thus, we have a robust tool for producing high quality, detailed kinetic parameters, which we have used to refine mechanisms presented in the literature and discover relationships between steric and electronic properties of group IV catalysts and individual rate constants in a number of systems. Our recent work on six-coordinate Zr, Ti, and Hf amine bis(phenolate) systems, we have shown that: • The sterics (bulkiness) of the ligands specifically affect the chain termination reaction • The electron density on the metal controls misinsertion (flipped orientation) of the olefin into the growing polymer • Steric effects related to the size of the ortho ligand on the catalyst have been shown to strongly affect its the degree of dormancy, i.e. tendency to stop reacting • Changes in the size of the amine pendent group on the catalyst can have such a strong effect on chain termination as to change the catalyst from one that produces only oligomers to one that incorporates oligomers in polymer chains to introduce chain branching. These effects control the length of molecular chains, the number of errors in the regularity of the chains, and the variation of chain lengths in the final product distribution. These characteristics, in turn, determine the properties of the resulting polymer material. Predictive modeling of polymerization process cannot be done without the quantitative rate constant determination that our unique and comprehensive approach has produced. This tool, combined with insights on how catalyst chemistry affects the rate constants, is an important step toward establishing the quantitative relationships between catalyst chemistry and polymer properties that will allow more efficient searches for new catalysts and speed the discovery process. Thus, in both the heterogeneous and homogeneous catalysis areas, this work has brought important new understanding to the field. The technical effectiveness of our approach is demonstrated by its success. For heterogeneous catalysis, experimental work alone showed the important of the metal-support interface, but the integration with theory has allowed deeper understanding of the fundamental source of the effects and shown the path for how to use this understanding for discovery. In the case of homogeneous catalysis, methodology for determination of which reactions are needed to account for the data and the extraction of quantitative values for rate constants for those reactions allows accurate modeling of reaction behavior. This allowed correlation of trends in catalyst properties with alterations of specific rates, thus contributing to a data base that will guide catalyst discovery. While not yet realized, the economic benefits of this approach will come in significantly shortened cycle times for discovery and ability to fill product demand at lower price.« less

  10. GREENING OF OXIDATION CATALYSIS THROUGH IMPROVED CATALYST AND PROCESS DESIGN

    EPA Science Inventory


    Greening of Oxidation Catalysis Through Improved Catalysts and Process Design
    Michael A. Gonzalez*, Thomas Becker, and Raymond Smith

    United State Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W...

  11. Core–shell nanoparticles: synthesis and applications in catalysis and electrocatalysis

    EPA Science Inventory

    Core–shell nanoparticles (CSNs) are a class of nanostructured materials that have recently received increased attention owing to their interesting properties and broad range of applications in catalysis, biology, materials chemistry and sensors. By rationally tuning the cores as ...

  12. Tandem rhodium catalysis:Exploiting sulfoxides for asymmetric transition-metal catalysis

    PubMed Central

    Kou, K. G. M.

    2015-01-01

    Sulfoxides are uncommon substrates for transition-metal catalysis due to their propensity to inhibit catalyst turnover. In a collaborative effort with Ken Houk, we developed the first dynamic kinetic resolution (DKR) of allylic sulfoxides using asymmetric rhodium-catalyzed hydrogenation. Detailed mechanistic analysis of this transformation using both experimental and theoretical methods revealed rhodium to be a tandem catalyst that promoted both hydrogenation of the alkene and racemization of the allylic sulfoxide. Using a combination of deuterium labelling and DFT studies, a novel mode of allylic sulfoxide racemization via a Rh(III)-π-allyl intermediate was identified. PMID:25940066

  13. Photoredox Catalysis in Organic Chemistry

    PubMed Central

    2016-01-01

    In recent years, photoredox catalysis has come to the forefront in organic chemistry as a powerful strategy for the activation of small molecules. In a general sense, these approaches rely on the ability of metal complexes and organic dyes to convert visible light into chemical energy by engaging in single-electron transfer with organic substrates, thereby generating reactive intermediates. In this Perspective, we highlight the unique ability of photoredox catalysis to expedite the development of completely new reaction mechanisms, with particular emphasis placed on multicatalytic strategies that enable the construction of challenging carbon–carbon and carbon–heteroatom bonds. PMID:27477076

  14. Multi-catalysis cascade reactions based on the methoxycarbonylketene platform: diversity-oriented synthesis of functionalized non-symmetrical malonates for agrochemicals and pharmaceuticals.

    PubMed

    Ramachary, Dhevalapally B; Venkaiah, Chintalapudi; Reddy, Y Vijayendar; Kishor, Mamillapalli

    2009-05-21

    In this paper we describe new multi-catalysis cascade (MCC) reactions for the one-pot synthesis of highly functionalized non-symmetrical malonates. These metal-free reactions are either five-step (olefination/hydrogenation/alkylation/ketenization/esterification) or six-step (olefination/hydrogenation/alkylation/ketenization/esterification/alkylation), and employ aldehydes/ketones, Meldrum's acid, 1,4-dihydropyridine/o-phenylenediamine, diazomethane, alcohols and active ethylene/acetylenes, and involve iminium-, self-, self-, self- and base-catalysis, respectively. Many of the products have direct application in agricultural and pharmaceutical chemistry.

  15. Synthesis of (-)-pseudotabersonine, (-)-pseudovincadifformine, and (+)-coronaridine enabled by photoredox catalysis in flow.

    PubMed

    Beatty, Joel W; Stephenson, Corey R J

    2014-07-23

    Natural product modification with photoredox catalysis allows for mild, chemoselective access to a wide array of related structures in complex areas of chemical space, providing the possibility for novel structural motifs as well as useful quantities of less abundant congeners. While amine additives have been used extensively as stoichiometric electron donors for photocatalysis, the controlled modification of amine substrates through single-electron oxidation is ideal for the synthesis and modification of alkaloids. Here, we report the conversion of the amine (+)-catharanthine into the natural products (-)-pseudotabersonine, (-)-pseudovincadifformine, and (+)-coronaridine utilizing visible light photoredox catalysis.

  16. Silyl Radical Activation of Alkyl Halides in Metallaphotoredox Catalysis: A Unique Pathway for Cross-Electrophile Coupling.

    PubMed

    Zhang, Patricia; Le, Chi Chip; MacMillan, David W C

    2016-07-06

    A strategy for cross-electrophile coupling has been developed via the merger of photoredox and transition metal catalysis. In this report, we demonstrate the use of commercially available tris(trimethylsilyl)silane with metallaphotoredox catalysis to efficiently couple alkyl bromides with aryl or heteroaryl bromides in excellent yields. We hypothesize that a photocatalytically generated silyl radical species can perform halogen-atom abstraction to activate alkyl halides as nucleophilic cross-coupling partners. This protocol allows the use of mild yet robust conditions to construct Csp(3)-Csp(2) bonds generically via a unique cross-coupling pathway.

  17. Tandem rhodium catalysis: exploiting sulfoxides for asymmetric transition-metal catalysis.

    PubMed

    Kou, K G M; Dong, V M

    2015-06-07

    Sulfoxides are uncommon substrates for transition-metal catalysis due to their propensity to inhibit catalyst turnover. In a collaborative effort with Ken Houk, we developed the first dynamic kinetic resolution (DKR) of allylic sulfoxides using asymmetric rhodium-catalyzed hydrogenation. A detailed mechanistic analysis of this transformation using both experimental and theoretical methods revealed rhodium to be a tandem catalyst that promoted both hydrogenation of the alkene and racemization of the allylic sulfoxide. Using a combination of deuterium labelling and DFT studies, a novel mode of allylic sulfoxide racemization via a Rh(III)-π-allyl intermediate was identified.

  18. Bridging the Gap Between Theory and Experiment to Derive a Detailed Understanding of Hammerhead Ribozyme Catalysis

    PubMed Central

    Lee, Tai-Sung; Wong, Kin-Yiu; Giambasu, George M.; York, Darrin M.

    2016-01-01

    Herein we summarize our progress toward the understanding of hammerhead ribozyme (HHR) catalysis through a multiscale simulation strategy. Simulation results collectively paint a picture of HHR catalysis: HHR first folds to form an electronegative active site pocket to recruit a threshold occupation of cationic charges, either a Mg2+ ion or multiple monovalent cations. Catalytically active conformations that have good in-line fitness are supported by specific metal ion coordination patterns that involve either a bridging Mg2+ ion or multiple Na+ ions, one of which is also in a bridging coordination pattern. In the case of a single Mg2+ ion bound in the active site, the Mg2+ ion undergoes a migration that is coupled with deprotonation of the nucleophile (C17:O2′). As the reaction proceeds, the Mg2+ ion stabilizes the accumulating charge of the leaving group and significantly increases the general acid ability of G8:O2′. Further computational mutagenesis simulations suggest that the disruptions due to mutations may severely impact HHR catalysis at different stages of the reaction. Catalytic mechanisms supported by the simulation results are consistent with available structural and biochemical experiments, and together they advance our understanding of HHR catalysis. PMID:24156941

  19. Ionic Liquid Droplet Microreactor for Catalysis Reactions Not at Equilibrium.

    PubMed

    Zhang, Ming; Ettelaie, Rammile; Yan, Tao; Zhang, Suojiang; Cheng, Fangqin; Binks, Bernard P; Yang, Hengquan

    2017-12-06

    We develop a novel strategy to more effectively and controllably process continuous enzymatic or homogeneous catalysis reactions based on nonaqueous Pickering emulsions. A key element of this strategy is "bottom-up" construction of a macroscale continuous flow reaction system through packing catalyst-containing micron-sized ionic liquid (IL) droplet in oil in a column reactor. Due to the continuous influx of reactants into the droplet microreactors and the continuous release of products from the droplet microreactors, catalysis reactions in such a system can take place without limitations arising from establishment of the reaction equilibrium and catalyst separation, inherent in conventional batch reactions. As proof of the concept, enzymatic enantioselective trans-esterification and CuI-catalyzed cycloaddition reactions using this IL droplet-based flow system both exhibit 8 to 25-fold enhancement in catalysis efficiency compared to their batch counterparts, and a durability of at least 4000 h for the enantioselective trans-esterification of 1-phenylethyl alcohol, otherwise unattainable in their batch counterparts. We further establish a theoretical model for such a catalysis system working under nonequilibrium conditions, which not only supports the experimental results but also helps to predict reaction progress at a microscale level. Being operationally simple, efficient, and adaptive, this strategy provides an unprecedented platform for practical applications of enzymes and homogeneous catalysts even at a controllable level.

  20. An Acrobatic Substrate Metamorphosis Reveals a Requirement for Substrate Conformational Dynamics in Trypsin Proteolysis*

    PubMed Central

    Kayode, Olumide; Wang, Ruiying; Pendlebury, Devon F.; Cohen, Itay; Henin, Rachel D.; Hockla, Alexandra; Soares, Alexei S.; Papo, Niv; Caulfield, Thomas R.; Radisky, Evette S.

    2016-01-01

    The molecular basis of enzyme catalytic power and specificity derives from dynamic interactions between enzyme and substrate during catalysis. Although considerable effort has been devoted to understanding how conformational dynamics within enzymes affect catalysis, the role of conformational dynamics within protein substrates has not been addressed. Here, we examine the importance of substrate dynamics in the cleavage of Kunitz-bovine pancreatic trypsin inhibitor protease inhibitors by mesotrypsin, finding that the varied conformational dynamics of structurally similar substrates can profoundly impact the rate of catalysis. A 1.4-Å crystal structure of a mesotrypsin-product complex formed with a rapidly cleaved substrate reveals a dramatic conformational change in the substrate upon proteolysis. By using long all-atom molecular dynamics simulations of acyl-enzyme intermediates with proteolysis rates spanning 3 orders of magnitude, we identify global and local dynamic features of substrates on the nanosecond-microsecond time scale that correlate with enzymatic rates and explain differential susceptibility to proteolysis. By integrating multiple enhanced sampling methods for molecular dynamics, we model a viable conformational pathway between substrate-like and product-like states, linking substrate dynamics on the nanosecond-microsecond time scale with large collective substrate motions on the much slower time scale of catalysis. Our findings implicate substrate flexibility as a critical determinant of catalysis. PMID:27810896

  1. An Acrobatic Substrate Metamorphosis Reveals a Requirement for Substrate Conformational Dynamics in Trypsin Proteolysis

    DOE PAGES

    Kayode, Olumide; Wang, Ruiying; Pendlebury, Devon F.; ...

    2016-11-03

    The molecular basis of enzyme catalytic power and specificity derives from dynamic interactions between enzyme and substrate during catalysis. While considerable effort has been devoted to understanding how conformational dynamics within enzymes affect catalysis, the role of conformational dynamics within protein substrates has not been addressed. Here in this paper, we examine the importance of substrate dynamics in the cleavage of Kunitz-BPTI protease inhibitors by mesotrypsin, finding that the varied conformational dynamics of structurally similar substrates can profoundly impact the rate of catalysis. A 1.4 Å crystal structure of a mesotrypsin-product complex formed with a rapidly cleaved substrate reveals amore » dramatic conformational change in the substrate upon proteolysis. Using long all-atom molecular dynamics simulations of acyl-enzyme intermediates with proteolysis rates spanning three orders of magnitude, we identify global and local dynamic features of substrates on the ns-μs timescale that correlate with enzymatic rates and explain differential susceptibility to proteolysis. By integrating multiple enhanced sampling methods for molecular dynamics, we model a viable conformational pathway between substratelike and product-like states, linking substrate dynamics on the ns-μs timescale with large collective substrate motions on the much slower timescale of catalysis. Our findings implicate substrate flexibility as a critical determinant of catalysis.« less

  2. Illinois Clean Coal Institute 2005 annual report. Final technical report for the period September 1st, 2004, through August 31, 2005 on projects funded by the Illinois Department of Commerce and Economic Opportunity

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

    NONE

    2005-11-08

    This final technical report contains the abstracts and executive summaries of projects funded through the Illinois Clean Coal Institute solicitation entitled 'Request for proposals No. 04-1(ICCI/RFP04-1)'. Support of these projects is by the Office of Coal Development and Department of Commerce and Economic Opportunity. The projects fall into the following categories: advanced coal mining technologies; coal preparation and coal production business practice; management of coal combustion byproducts; commercialization and technology transfer. Final project extensions are also recorded.

  3. Renewable Fuel Standard (RFS2): Final Rule Additional Resources

    EPA Pesticide Factsheets

    The final rule of fuels and fuel additives: renewable fuel standard program is published on March 26, 2010 and is effective on July 1, 2010. You will find the links to this final rule and technical amendments supporting this rule.

  4. 75 FR 48273 - Technical Service Provider Assistance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-10

    ... DEPARTMENT OF AGRICULTURE Natural Resources Conservation Service 7 CFR Part 652 RIN 0578-AA48 Technical Service Provider Assistance AGENCY: Natural Resources Conservation Service, United States Department of Agriculture. ACTION: Final rule; Correcting amendment. SUMMARY: The Natural Resources...

  5. Partial Withdrawal and Final Rule for Nonroad Technical Amendments

    EPA Pesticide Factsheets

    Amendments to the technical hardship provisions under the Transition Program for Equipment Manufacturers related to the Tier 4 standards for nonroad diesel engines, and to the replacement engine exemption generally applicable to new nonroad engines.

  6. 2D and 3D imaging of the gas phase close to an operating model catalyst by planar laser induced fluorescence

    NASA Astrophysics Data System (ADS)

    Blomberg, Sara; Zhou, Jianfeng; Gustafson, Johan; Zetterberg, Johan; Lundgren, Edvin

    2016-11-01

    In recent years, efforts have been made in catalysis related surface science studies to explore the possibilities to perform experiments at conditions closer to those of a technical catalyst, in particular at increased pressures. Techniques such as high pressure scanning tunneling/atomic force microscopy (HPSTM/AFM), near ambient pressure x-ray photoemission spectroscopy (NAPXPS), surface x-ray diffraction (SXRD) and polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS) at semi-realistic conditions have been used to study the surface structure of model catalysts under reaction conditions, combined with simultaneous mass spectrometry (MS). These studies have provided an increased understanding of the surface dynamics and the structure of the active phase of surfaces and nano particles as a reaction occurs, providing novel information on the structure/activity relationship. However, the surface structure detected during the reaction is sensitive to the composition of the gas phase close to the catalyst surface. Therefore, the catalytic activity of the sample itself will act as a gas-source or gas-sink, and will affect the surface structure, which in turn may complicate the assignment of the active phase. For this reason, we have applied planar laser induced fluorescence (PLIF) to the gas phase in the vicinity of an active model catalysts. Our measurements demonstrate that the gas composition differs significantly close to the catalyst and at the position of the MS, which indeed should have a profound effect on the surface structure. However, PLIF applied to catalytic reactions presents several beneficial properties in addition to investigate the effect of the catalyst on the effective gas composition close to the model catalyst. The high spatial and temporal resolution of PLIF provides a unique tool to visualize the on-set of catalytic reactions and to compare different model catalysts in the same reactive environment. The technique can be applied to a large number of molecules thanks to the technical development of lasers and detectors over the last decades, and is a complementary and visual alternative to traditional MS to be used in environments difficult to asses with MS. In this article we will review general considerations when performing PLIF experiments, our experimental set-up for PLIF and discuss relevant examples of PLIF applied to catalysis.

  7. Time-resolved chromatographic analysis and mechanisms in adsorption and catalysis.

    PubMed

    Roubani-Kalantzopoulou, Fani

    2009-03-06

    The main object of this review is the study of fundamentals of adsorption and heterogeneous catalysis, a benefit for the understanding of adsorptive and catalytic properties. This work aims to define and record, with the utmost accuracy, the phenomena and the possible reactions. A new methodology for the study of the adsorption is presented, which is a version of the well-known inverse gas chromatography. This reversed-flow inverse gas chromatography (RF-IGC) is technically very simple, and it is combined with a mathematical analysis that gives the possibility for the estimation of various physicochemical parameters related to adsorbent or catalyst characterization, under conditions compatible with the operation of real adsorbents and catalysts. On this base, this methodology has been successfully applied to the study of the impact of air pollutants, volatile organic and/or inorganic, on many solids such as marbles, ceramics, oxide-pigments of works of art, building materials, authentic statues of the Greek Archaeological Museums. Moreover, this methodology proved to be a powerful tool for studying the topography of active sites of heterogeneous surfaces in the nano-scale domain. Thus, some very important local quantities for the surface chemistry have been determined experimentally for many solids including thin films. These physicochemical local quantities (among which adsorption energy and entropy, surface diffusion coefficient, probability density function) have been determined from the experimental pairs of height of extra chromatographic peaks and time by a nonlinear least-squares method, through personal computer programs written in GW BASIC and lately in FORTRAN. Through the time-resolved analysis the surface characterization of the examined materials took place. In addition, the kinetic constants responsible for adsorption/desorption and surface chemical reactions have also been calculated. Thus, important answers have been provided to the following essential questions: (1) Can RF-IGC define the gnostic regions of adsorption/desorption, surface diffusion, surface reaction? Yes, irrefutably and undeniably. (2) Can RF-IGC deal with issues of catalysis, the existence of more than one reaction? Certainly yes. Indeed, it is impressive to observe the reactions "on line". (3) Can RF-IGC identify peaks of products and reactants simultaneously? Certainly yes. (4) Can RF-IGC be applied to thin films in a nano-scale domain? The answer is "definitely yes". (5) Can it kinetically follow the above? Yes, again.

  8. Green Chemistry by Nano-Catalysis

    EPA Science Inventory

    The approach of using MW technique with nano-catalysis and benign aqueous reaction medium can offer an extraordinary synergistic effect with greater potential than these three individual components in isolation. To illustrate the ‘‘proof-of-concept’’ of this “Green and Sustainabl...

  9. The balance of electric field and interfacial catalysis in promoting water dissociation in bipolar membranes

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

    Yan, Zhifei; Zhu, Liang; Li, Yuguang C.

    Bipolar membranes maintain a steady pH in electrolytic cells through water autodissociation at the interface between their cation- and anion-exchange layers. We analyze the balance of electric field and catalysis in accelerating this reaction.

  10. The balance of electric field and interfacial catalysis in promoting water dissociation in bipolar membranes

    DOE PAGES

    Yan, Zhifei; Zhu, Liang; Li, Yuguang C.; ...

    2018-01-01

    Bipolar membranes maintain a steady pH in electrolytic cells through water autodissociation at the interface between their cation- and anion-exchange layers. We analyze the balance of electric field and catalysis in accelerating this reaction.

  11. Diffusion and Surface Reaction in Heterogeneous Catalysis

    ERIC Educational Resources Information Center

    Baiker, A.; Richarz, W.

    1978-01-01

    Ethylene hydrogenation on a platinum catalyst, electrolytically applied to a tube wall, is a good system for the study of the interactions between diffusion and surface reaction in heterogeneous catalysis. Theoretical background, apparatus, procedure, and student performance of this experiment are discussed. (BB)

  12. A Pilot Program to Provide Ownership Skills to Seniors in the Vocational Technical Schools and Other Educational Institutions, Year Two. Final Report.

    ERIC Educational Resources Information Center

    Norwich Regional Vocational Technical School, CT.

    Responding to a Small Business Administration statement that technical school graduates lack knowledge of business principles, the Norwich (Connecticut) Regional Vocational Technical School conducted a course in small business ownership/management for all of its seniors. The required course, a fifty-four-hour module, replaced one English,…

  13. A Case Study of Technical Assistance to Demonstration Programs for Young Handicapped Children. Part III.

    ERIC Educational Resources Information Center

    Behr, Shirley K.; And Others

    The report describes the third and final year of a 3-year case study of the technical assistance process as implemented by the Technical Assistance Development System (TADS) for the staffs of two demonstration programs for preschool handicapped children and their families. Following a review of TADS and the two demonstration programs, the…

  14. Effects of Cavities at the Nicotinamide Binding Site of Liver Alcohol Dehydrogenase on Structure, Dynamics and Catalysis

    PubMed Central

    2015-01-01

    A role for protein dynamics in enzymatic catalysis of hydrogen transfer has received substantial scientific support, but the connections between protein structure and catalysis remain to be established. Valine residues 203 and 207 are at the binding site for the nicotinamide ring of the coenzyme in liver alcohol dehydrogenase and have been suggested to facilitate catalysis with “protein-promoting vibrations” (PPV). We find that the V207A substitution has small effects on steady-state kinetic constants and the rate of hydrogen transfer; the introduced cavity is empty and is tolerated with minimal effects on structure (determined at 1.2 Å for the complex with NAD+ and 2,3,4,5,6-pentafluorobenzyl alcohol). Thus, no evidence is found to support a role for Val-207 in the dynamics of catalysis. The protein structures and ligand geometries (including donor–acceptor distances) in the V203A enzyme complexed with NAD+ and 2,3,4,5,6-pentafluorobenzyl alcohol or 2,2,2-trifluoroethanol (determined at 1.1 Å) are very similar to those for the wild-type enzyme, except that the introduced cavity accommodates a new water molecule that contacts the nicotinamide ring. The structures of the V203A enzyme complexes suggest, in contrast to previous studies, that the diminished tunneling and decreased rate of hydride transfer (16-fold, relative to that of the wild-type enzyme) are not due to differences in ground-state ligand geometries. The V203A substitution may alter the PPV and the reorganization energy for hydrogen transfer, but the protein scaffold and equilibrium thermal motions within the Michaelis complex may be more significant for enzyme catalysis. PMID:24437493

  15. Conformational Plasticity of an Enzyme during Catalysis: Intricate Coupling between Cyclophilin A Dynamics and Substrate Turnover

    PubMed Central

    McGowan, Lauren C.; Hamelberg, Donald

    2013-01-01

    Enzyme catalysis is central to almost all biochemical processes, speeding up rates of reactions to biological relevant timescales. Enzymes make use of a large ensemble of conformations in recognizing their substrates and stabilizing the transition states, due to the inherent dynamical nature of biomolecules. The exact role of these diverse enzyme conformations and the interplay between enzyme conformational dynamics and catalysis is, according to the literature, not well understood. Here, we use molecular dynamics simulations to study human cyclophilin A (CypA), in order to understand the role of enzyme motions in the catalytic mechanism and recognition. Cyclophilin A is a tractable model system to study using classical simulation methods, because catalysis does not involve bond formation or breakage. We show that the conformational dynamics of active site residues of substrate-bound CypA is inherent in the substrate-free enzyme. CypA interacts with its substrate via conformational selection as the configurations of the substrate changes during catalysis. We also show that, in addition to tight intermolecular hydrophobic interactions between CypA and the substrate, an intricate enzyme-substrate intermolecular hydrogen-bonding network is extremely sensitive to the configuration of the substrate. These enzyme-substrate intermolecular interactions are loosely formed when the substrate is in the reactant and product states and become well formed and reluctant to break when the substrate is in the transition state. Our results clearly suggest coupling among enzyme-substrate intermolecular interactions, the dynamics of the enzyme, and the chemical step. This study provides further insights into the mechanism of peptidyl-prolyl cis/trans isomerases and the general interplay between enzyme conformational dynamics and catalysis. PMID:23332074

  16. Conformational plasticity of an enzyme during catalysis: intricate coupling between cyclophilin A dynamics and substrate turnover.

    PubMed

    McGowan, Lauren C; Hamelberg, Donald

    2013-01-08

    Enzyme catalysis is central to almost all biochemical processes, speeding up rates of reactions to biological relevant timescales. Enzymes make use of a large ensemble of conformations in recognizing their substrates and stabilizing the transition states, due to the inherent dynamical nature of biomolecules. The exact role of these diverse enzyme conformations and the interplay between enzyme conformational dynamics and catalysis is, according to the literature, not well understood. Here, we use molecular dynamics simulations to study human cyclophilin A (CypA), in order to understand the role of enzyme motions in the catalytic mechanism and recognition. Cyclophilin A is a tractable model system to study using classical simulation methods, because catalysis does not involve bond formation or breakage. We show that the conformational dynamics of active site residues of substrate-bound CypA is inherent in the substrate-free enzyme. CypA interacts with its substrate via conformational selection as the configurations of the substrate changes during catalysis. We also show that, in addition to tight intermolecular hydrophobic interactions between CypA and the substrate, an intricate enzyme-substrate intermolecular hydrogen-bonding network is extremely sensitive to the configuration of the substrate. These enzyme-substrate intermolecular interactions are loosely formed when the substrate is in the reactant and product states and become well formed and reluctant to break when the substrate is in the transition state. Our results clearly suggest coupling among enzyme-substrate intermolecular interactions, the dynamics of the enzyme, and the chemical step. This study provides further insights into the mechanism of peptidyl-prolyl cis/trans isomerases and the general interplay between enzyme conformational dynamics and catalysis. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  17. Synergistic Anion-(π) n-π Catalysis on π-Stacked Foldamers.

    PubMed

    Bornhof, Anna-Bea; Bauzá, Antonio; Aster, Alexander; Pupier, Marion; Frontera, Antonio; Vauthey, Eric; Sakai, Naomi; Matile, Stefan

    2018-04-11

    In this report, we demonstrate that synergistic effects between π-π stacking and anion-π interactions in π-stacked foldamers provide access to unprecedented catalytic activity. To elaborate on anion-(π) n -π catalysis, we have designed, synthesized and evaluated a series of novel covalent oligomers with up to four face-to-face stacked naphthalenediimides (NDIs). NMR analysis including DOSY confirms folding into π stacks, cyclic voltammetry, steady-state and transient absorption spectroscopy the electronic communication within the π stacks. Catalytic activity, assessed by chemoselective catalysis of the intrinsically disfavored but biologically relevant addition reaction of malonate half thioesters to enolate acceptors, increases linearly with the length of the stacks to reach values that are otherwise beyond reach. This linear increase violates the sublinear power laws of oligomer chemistry. The comparison of catalytic activity with ratiometric changes in absorption and decreasing energy of the LUMO thus results in superlinearity, that is synergistic amplification of anion-π catalysis by remote control over the entire stack. In computational models, increasing length of the π-stacked foldamers correlates sublinearly with changes in surface potentials, chloride binding energies, and the distances between chloride and π surface and within the π stack. Computational evidence is presented that the selective acceleration of disfavored but relevant enolate chemistry by anion-π catalysis indeed originates from the discrimination of planar and bent tautomers with delocalized and localized charges, respectively, on π-acidic surfaces. Computed binding energies of keto and enol intermediates of the addition reaction as well as their difference increase with increasing length of the π stack and thus reflect experimental trends correctly. These results demonstrate that anion-(π) n -π interactions exist and matter, ready for use as a unique new tool in catalysis and beyond.

  18. Chemical Durability Improvement and Static Fatigue of Glasses.

    DTIC Science & Technology

    1982-08-01

    Afl-Alla 837 RENSSELAER POLYIECmfJ!C INST TRtOY NY DEPT OF MATERIAL--ETC F/6 ii/ CHEMICAL DURABILITY IMPROVEMENT AND STATIC FATIGUE OF GLASSESW AUC2...82 M TOMOZAWA NOGGIN 7A-C-0315 UNC LASS IF IED N ENEEEEEE FINAL TECHNICAL REPORT For the period April 1, 1978 "u March 31, 198200 CHEMICAL DURABILITY...REPORT A PERIOD COVERED Chemical Durability Improvement and Static Final Technical Report Fatiue o GlasesApril 1, 1978"’,March 31, 1982 S. PERFORMING ORG

  19. Experimental Program Final Technical Progress Report: 15 February 2007 to 30 September 2012

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

    Kinney, Edward R.

    2014-09-12

    This is the final technical report of the grant DE-FG02-04ER41301 to the University of Colorado at Boulder entitled "Intermediate Energy Nuclear Physics" and describes the results of our funded activities during the period 15 February 2007 to 30 September 2012. These activities were primarily carried out at Fermilab, RHIC, and the German lab DESY. Significant advances in these experiments were carried out by members of the Colorado group and are described in detail.

  20. Final Technical Report - Center for Technology for Advanced Scientific Component Software (TASCS)

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

    Sussman, Alan

    2014-10-21

    This is a final technical report for the University of Maryland work in the SciDAC Center for Technology for Advanced Scientific Component Software (TASCS). The Maryland work focused on software tools for coupling parallel software components built using the Common Component Architecture (CCA) APIs. Those tools are based on the Maryland InterComm software framework that has been used in multiple computational science applications to build large-scale simulations of complex physical systems that employ multiple separately developed codes.

  1. Iowa Hill Pumped Storage Project Investigations - Final Technical Report

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

    Hanson, David

    2016-07-01

    This Final Technical Report is a summary of the activities and outcome of the Department of Energy (DOE) Assistance Agreement DE-EE0005414 with the Sacramento Municipal Utility District (SMUD). The Assistance Agreement was created in 2012 to support investigations into the Iowa Hill Pumped-storage Project (Project), a new development that would add an additional 400 MW of capacity to SMUD’s existing 688MW Upper American River Hydroelectric Project (UARP) in the Sierra Nevada mountains east of Sacramento, California.

  2. Renewable Fuel Standard Program (RFS1): Final Rule Additional Resources

    EPA Pesticide Factsheets

    The final rule of fuels and fuel additives: renewable fuel standard program is published on May 1, 2007 and is effective on September 1, 2007. You will find the links to this final rule and technical amendments supporting this rule.

  3. Assurance Penalty Level Analysis Final Rule TSD

    EPA Pesticide Factsheets

    This Technical Support Document (TSD) supports EPA’s determination that the final Transport Rule’s assurance provision penalty requirement provides sufficient deterrence against a state exceeding its assurance level.

  4. Free Radical Chemistry Enabled by Visible Light-Induced Electron Transfer

    PubMed Central

    2016-01-01

    Conspectus Harnessing visible light as the driving force for chemical transformations generally offers a more environmentally friendly alternative compared with classical synthetic methodology. The transition metal-based photocatalysts commonly employed in photoredox catalysis absorb efficiently in the visible spectrum, unlike most organic substrates, allowing for orthogonal excitation. The subsequent excited states are both more reducing and more oxidizing than the ground state catalyst and are competitive with some of the more powerful single-electron oxidants or reductants available to organic chemists yet are simply accessed via irradiation. The benefits of this strategy have proven particularly useful in radical chemistry, a field that traditionally employs rather toxic and hazardous reagents to generate the desired intermediates. In this Account, we discuss our efforts to leverage visible light photoredox catalysis in radical-based bond-forming and bond-cleaving events for which few, if any, environmentally benign alternatives exist. Mechanistic investigations have driven our contributions in this field, for both facilitating desired transformations and offering new, unexpected opportunities. In fact, our total synthesis of (+)-gliocladin C was only possible upon elucidating the propensity for various trialkylamine additives to elicit a dual behavior as both a reductive quencher and a H-atom donor. Importantly, while natural product synthesis was central to our initial motivations to explore these photochemical processes, we have since demonstrated applicability within other subfields of chemistry, and our evaluation of flow technologies demonstrates the potential to translate these results from the bench to pilot scale. Our forays into photoredox catalysis began with fundamental methodology, providing a tin-free reductive dehalogenation that exchanged the gamut of hazardous reagents previously employed for such a transformation for visible light-mediated, ambient temperature conditions. Evolving from this work, a new avenue toward atom transfer radical addition (ATRA) chemistry was developed, enabling dual functionalization of both double and triple bonds. Importantly, we have also expanded our portfolio to target clinically relevant scaffolds. Photoredox catalysis proved effective in generating high value fluorinated alkyl radicals through the use of abundantly available starting materials, providing access to libraries of trifluoromethylated (hetero)arenes as well as intriguing gem-difluoro benzyl motifs via a novel photochemical radical Smiles rearrangement. Finally, we discuss a photochemical strategy toward sustainable lignin processing through selective C–O bond cleavage methodology. The collection of these efforts is meant to highlight the potential for visible light-mediated radical chemistry to impact a variety of industrial sectors. PMID:27529484

  5. Final Rule for Technical Amendments to the Highway and Nonroad Diesel Regulations

    EPA Pesticide Factsheets

    This action corrects errors and omissions from the previous rules, makes minor changes to the regulations to assist entities with regulatory compliance, and makes technical amendments that resulted from discussions with various diesel stakeholders.

  6. Japanese Research Institutes Funded by Ministries Other Than Education.

    DTIC Science & Technology

    1981-01-01

    Cemistry department Dental department Technological laboratory Name: National Institute of Hospital Administration Location 1, Toyama-cho, Shinjuku...68 CARBON 46 CATALYSIS 46 CATALYSIS 70 CATTLE 24 CATTLE 34 CEMISTRY 13 CERAMIC 47 CERAMIC 47 CHEMICAL 27 CHEMICAL 46 CHEMICAL 49 CHEMICAL 69 CHEMICAL

  7. Cascade catalysis for the homogeneous hydrogenation of CO2 to methanol.

    PubMed

    Huff, Chelsea A; Sanford, Melanie S

    2011-11-16

    This communication demonstrates the homogeneous hydrogenation of CO(2) to CH(3)OH via cascade catalysis. Three different homogeneous catalysts, (PMe(3))(4)Ru(Cl)(OAc), Sc(OTf)(3), and (PNN)Ru(CO)(H), operate in sequence to promote this transformation.

  8. Advances in Gold Catalysis and Understanding the Catalytic Mechanism.

    PubMed

    Ishida, Tamao; Koga, Hiroaki; Okumura, Mitsutaka; Haruta, Masatake

    2016-10-01

    When gold is deposited as nanoparticles (NPs) with mean diameters of 2-5 nm or clusters with mean diameters below 2 nm onto a variety of supports such as metal oxides, carbons, polymers, etc., the supported Au NPs exhibit unique catalytic properties, while bulk Au is almost inert as a catalyst. A lot of research works indicate that the key factors of the catalysis by supported Au NPs are the selection of the supports, the control of the Au NP size, the shape of the Au NPs, and the strong junction between Au NPs and the supports, because the perimeter zone around Au NPs acts as the active site for many reactions. In order to elucidate the origin of catalysis by supported Au NPs, the interplay between physicochemical analysis, computational studies, and rational experiments for catalysis by supported Au NPs is becoming more and more important. This article summarizes our experiences and progress in such interplay. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Quantifying ligand effects in high-oxidation-state metal catalysis

    NASA Astrophysics Data System (ADS)

    Billow, Brennan S.; McDaniel, Tanner J.; Odom, Aaron L.

    2017-09-01

    Catalysis by high-valent metals such as titanium(IV) impacts our lives daily through reactions like olefin polymerization. In any catalysis, optimization involves a careful choice of not just the metal but also the ancillary ligands. Because these choices dramatically impact the electronic structure of the system and, in turn, catalyst performance, new tools for catalyst development are needed. Understanding ancillary ligand effects is arguably one of the most critical aspects of catalyst optimization and, while parameters for phosphines have been used for decades with low-valent systems, a comparable system does not exist for high-valent metals. A new electronic parameter for ligand donation, derived from experiments on a high-valent chromium species, is now available. Here, we show that the new parameters enable quantitative determination of ancillary ligand effects on catalysis rate and, in some cases, even provide mechanistic information. Analysing reactions in this way can be used to design better catalyst architectures and paves the way for the use of such parameters in a host of high-valent processes.

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

    Shi,J.; Sivaraman, J.; Song, J.

    Unlike 3C protease, the severe acute respiratory syndrome coronavirus (SARS-CoV) 3C-like protease (3CLpro) is only enzymatically active as a homodimer and its catalysis is under extensive regulation by the unique extra domain. Despite intense studies, two puzzles still remain: (i) how the dimer-monomer switch is controlled and (ii) why dimerization is absolutely required for catalysis. Here we report the monomeric crystal structure of the SARS-CoV 3CLpro mutant R298A at a resolution of 1.75 Angstroms . Detailed analysis reveals that Arg298 serves as a key component for maintaining dimerization, and consequently, its mutation will trigger a cooperative switch from a dimermore » to a monomer. The monomeric enzyme is irreversibly inactivated because its catalytic machinery is frozen in the collapsed state, characteristic of the formation of a short 310-helix from an active-site loop. Remarkably, dimerization appears to be coupled to catalysis in 3CLpro through the use of overlapped residues for two networks, one for dimerization and another for the catalysis.« less

  11. Final priority. Rehabilitation Training: Job-Driven Vocational Rehabilitation Technical Assistance Center. Final priority.

    PubMed

    2014-08-19

    The Assistant Secretary for Special Education and Rehabilitative Services announces a priority under the Rehabilitation Training program to establish a Job-Driven Vocational Rehabilitation Technical Assistance Center (JDVRTAC). The Assistant Secretary may use this priority for competitions in fiscal year (FY) 2014 and later years. We take this action to focus on training in an area of national need. Specifically, this priority responds to the Presidential Memorandum to Federal agencies directing them to take action to address job-driven training for the Nation's workers. The JDVRTAC will provide technical assistance (TA) to State vocational rehabilitation (VR) agencies to help them develop for individuals with disabilities training and employment opportunities that meet the needs of today's employers.

  12. Generating disulfides with the quiescin sulfhydryl oxidases

    PubMed Central

    Heckler, Erin J.; Rancy, Pumtiwitt C.; Kodali, Vamsi K.; Thorpe, Colin

    2008-01-01

    The Quiescin-sulfhydryl oxidase (QSOX) family of flavoenzymes catalyzes the direct and facile insertion of disulfide bonds into unfolded reduced proteins with concomitant reduction of oxygen to hydrogen peroxide. This review discusses the chemical mechanism of these enzymes and the involvement of thioredoxin and flavin-binding domains in catalysis. The variability of CxxC motifs in the QSOX family is highlighted and attention is drawn to the steric factors that may promote efficient thiol/disulfide exchange during oxidative protein folding. The varied cellular location of these multi-domain sulfhydryl oxidases is reviewed and potential intracellular and extracellular roles are summarized. Finally, this review identifies important unresolved questions concerning this ancient family of sulfhydryl oxidases. PMID:17980160

  13. Old Yellow Enzyme: Stepwise reduction of nitro-olefins and catalysis of aci-nitro tautomerization

    PubMed Central

    Meah, Younus; Massey, Vincent

    2000-01-01

    The Old Yellow Enzyme has been shown to catalyze efficiently the NADPH-linked reduction of nitro-olefins. The reduction of the nitro-olefin proceeds in a stepwise fashion, with formation of a nitronate intermediate that is freely dissociable from the enzyme. The first step involves hydride transfer from the enzyme-reduced flavin to carbon 2 of the nitro-olefin. The protonation of the nitronate at carbon 1 to form the final nitroalkane product also is catalyzed by the enzyme and involves Tyr-196 as an active site acid/base. This residue also is involved in aci-nitro tautomerization of nitroalkanes, the first example of a nonredox reaction catalyzed by the enzyme. PMID:10995477

  14. One-pot synthesis of 2,5-dihydropyrroles from terminal alkynes, azides, and propargylic alcohols by relay actions of copper, rhodium, and gold.

    PubMed

    Miura, Tomoya; Tanaka, Takamasa; Matsumoto, Kohei; Murakami, Masahiro

    2014-12-01

    Relay actions of copper, rhodium, and gold formulate a one-pot multistep pathway, which directly gives 2,5-dihydropyrroles starting from terminal alkynes, sulfonyl azides, and propargylic alcohols. Initially, copper-catalyzed 1,3-dipolar cycloaddition of terminal alkynes with sulfonyl azides affords 1-sulfonyl-1,2,3-triazoles, which then react with propargylic alcohols under the catalysis of rhodium. The resulting alkenyl propargyl ethers subsequently undergo the thermal Claisen rearrangement to give α-allenyl-α-amino ketones. Finally, a gold catalyst prompts 5-endo cyclization to produce 2,5-dihydropyrroles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. NASA's Pursuit of Low-Noise Propulsion for Low-Boom Commercial Supersonic Vehicles

    NASA Technical Reports Server (NTRS)

    Bridges, James; Brown, Clifford A.; Seidel, Jonathan A.

    2018-01-01

    Since 2006, when the Fundamental Aeronautics Program was instituted within NASA's Aeronautics Mission Directorate, there has been a Project looking at the technical barriers to commercial supersonic flight. Among the barriers is the noise produced by aircraft during landing and takeoff. Over the years that followed, research was carried out at NASA aeronautics research centers, often in collaboration with academia and industry, addressing the problem. In 2013, a high-level milestone was established, described as a Technical Challenge, with the objective of demonstrating the feasibility of a low-boom supersonic airliner that could meet current airport noise regulations. The Technical Challenge was formally called "Low Noise Propulsion for Low Boom Aircraft", and was completed in late 2016. This paper reports the technical findings from this Technical Challenge, reaching back almost 10 years to review the technologies and tools that were developed along the way. It also discusses the final aircraft configuration and propulsion systems required for a supersonic civilian aircraft to meet noise regulations using the technologies available today. Finally, the paper documents the model-scale tests that validated the acoustic performance of the study aircraft.

  16. NASA's Pursuit of Low-Noise Propulsion for Low-Boom Commercial Supersonic Vehicles

    NASA Technical Reports Server (NTRS)

    Bridges, James; Brown, Clifford A.; Seidel, Jonathan

    2018-01-01

    Since 2006, when the Fundamental Aeronautics Program was instituted within NASA's Aeronautics Mission Directorate, there has been a Project looking at the technical barriers to commercial supersonic flight. Among the barriers is the noise produced by aircraft during landing and takeoff. Over the years that followed, research was carried out at NASA aeronautics research centers, often in collaboration with academia and industry, addressing the problem. In 2013, a high-level milestone was established, described as a Technical Challenge, with the objective of demonstrating the feasibility of a low-boom supersonic airliner that could meet current airport noise regulations. The Technical Challenge was formally called a Low Noise Propulsion for Low Boom Aircraft and was completed in late 2016. This paper reports the technical findings from this Technical Challenge, reaching back almost 10 years to review the technologies and tools that were developed along the way. It also discusses the final aircraft configuration and propulsion systems required for a supersonic civilian aircraft to meet noise regulations using the technologies available today. Finally, the paper documents the model-scale tests that validated the acoustic performance of the study aircraft.

  17. Final Revisions Rule State Budgets and New Unit Set-Asides TSD

    EPA Pesticide Factsheets

    This technical support document shows the underlying data and calculations used to quantify the state budget revisions and new unit set-aside revisions made in the final revisions rule, as well as those revisions included in the direct final revisions rule

  18. Silver versus gold catalysis in tandem reactions of carbonyl functions onto alkynes: a versatile access to furoquinoline and pyranoquinoline cores.

    PubMed

    Godet, Thomas; Vaxelaire, Carine; Michel, Carine; Milet, Anne; Belmont, Philippe

    2007-01-01

    An efficient and versatile tandem process of acetalization and cycloisomerization reactions has been developed for the reactions of 1-alkynyl-2-carbonylquinoline substrates. The reaction occurs thanks to Au(I) and Ag(I) catalysis. Silver(I) catalysis has been extensively studied (11 different silver species) on a broad range of quinoline derivatives (variation of alkyne substituent, of carbonyl function and of nucleophiles), leading to a variety of furoquinoline and pyranoquinoline moieties. An insight is given for the presumed mechanism along with DFT-B3 LYP/6-31G** calculations to address the 6-endo and 5-exo regioselectivities observed.

  19. Heterogeneous atmospheric chemistry

    NASA Technical Reports Server (NTRS)

    Schryer, D. R.

    1982-01-01

    The present conference on heterogeneous atmospheric chemistry considers such topics concerning clusters, particles and microparticles as common problems in nucleation and growth, chemical kinetics, and catalysis, chemical reactions with aerosols, electron beam studies of natural and anthropogenic microparticles, and structural studies employing molecular beam techniques, as well as such gas-solid interaction topics as photoassisted reactions, catalyzed photolysis, and heterogeneous catalysis. Also discussed are sulfur dioxide absorption, oxidation, and oxidation inhibition in falling drops, sulfur dioxide/water equilibria, the evidence for heterogeneous catalysis in the atmosphere, the importance of heterogeneous processes to tropospheric chemistry, soot-catalyzed atmospheric reactions, and the concentrations and mechanisms of formation of sulfate in the atmospheric boundary layer.

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

    Lercher, Johannes

    PNNL’s catalysis research is serving as a catalyst for changing how our nation will secure a strong, clean energy future. Senior Physical Chemist Johannes Lercher leads an award-winning team that is developing catalysts that efficiently make fuels from alternate feedstocks, such as biomass, and can store electrical energy in chemical bonds. The researchers are also creating catalysts that can increase vehicle fuel efficiency, while simultaneously cutting emissions. About 80 percent of all man-made materials — from plastics to pharmaceuticals — are made using catalysts. Through PNNL’s Institute for Integrated Catalysis, Johannes and colleagues study how to speed the catalysis reactionmore » process for manufacturers, which ultimately cuts costs and production time.« less

  1. Positron studies in catalysis research

    NASA Astrophysics Data System (ADS)

    During the past eight months, the authors have made progress in several areas relevant to the eventual use of positron techniques in catalysis research. They have come closer to the completion of their positron microscope, and at the same time have performed several studies in their non-microscopic positron spectrometer which should ultimately be applicable to catalysis. The current status of the efforts in each of these areas is summarized in the following sections: Construction of the positron microscope (optical element construction, data collection software, and electronic sub-assemblies); Doppler broadening spectroscopy of metal silicide; Positron lifetime spectroscopy of glassy polymers; and Positron lifetime measurements of pore-sizes in zeolites.

  2. Enzyme catalysis: a new definition accounting for noncovalent substrate- and product-like states.

    PubMed

    Purich, D L

    2001-07-01

    Biological catalysis frequently causes changes in noncovalent bonding. By building on Pauling's assertion that any long-lived, chemically distinct interaction is a chemical bond, this article redefines enzyme catalysis as the facilitated making and/or breaking of chemical bonds, not just of covalent bonds. It is also argued that nearly every ATPase or GTPase is misnamed as a hydrolase and actually belongs to a distinct class of enzymes, termed here 'energases'. By transducing covalent bond energy into mechanical work, energases mediate such fundamental processes as protein folding, self-assembly, G-protein interactions, DNA replication, chromatin remodeling and even active transport.

  3. Visible-Light-Promoted Trifluoromethylthiolation of Styrenes by Dual Photoredox/Halide Catalysis.

    PubMed

    Honeker, Roman; Garza-Sanchez, R Aleyda; Hopkinson, Matthew N; Glorius, Frank

    2016-03-18

    Herein, we report a new visible-light-promoted strategy to access radical trifluoromethylthiolation reactions by combining halide and photoredox catalysis. This approach allows for the synthesis of vinyl-SCF3 compounds of relevance in pharmaceutical chemistry directly from alkenes under mild conditions with irradiation from household light sources. Furthermore, alkyl-SCF3-containing cyclic ketone and oxindole derivatives can be accessed by radical-polar crossover semi-pinacol and cyclization processes. Inexpensive halide salts play a crucial role in activating the trifluoromethylthiolating reagent towards photoredox catalysis and aid the formation of the SCF3 radical. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. The Development of Visible-Light Photoredox Catalysis in Flow.

    PubMed

    Garlets, Zachary J; Nguyen, John D; Stephenson, Corey R J

    2014-04-01

    Visible-light photoredox catalysis has recently emerged as a viable alternative for radical reactions otherwise carried out with tin and boron reagents. It has been recognized that by merging photoredox catalysis with flow chemistry, slow reaction times, lower yields, and safety concerns may be obviated. While flow reactors have been successfully applied to reactions carried out with UV light, only recent developments have demonstrated the same potential of flow reactors for the improvement of visible-light-mediated reactions. This review examines the initial and continuing development of visible-light-mediated photoredox flow chemistry by exemplifying the benefits of flow chemistry compared with conventional batch techniques.

  5. The Development of Visible-Light Photoredox Catalysis in Flow

    PubMed Central

    Garlets, Zachary J.; Nguyen, John D.

    2014-01-01

    Visible-light photoredox catalysis has recently emerged as a viable alternative for radical reactions otherwise carried out with tin and boron reagents. It has been recognized that by merging photoredox catalysis with flow chemistry, slow reaction times, lower yields, and safety concerns may be obviated. While flow reactors have been successfully applied to reactions carried out with UV light, only recent developments have demonstrated the same potential of flow reactors for the improvement of visible-light-mediated reactions. This review examines the initial and continuing development of visible-light-mediated photoredox flow chemistry by exemplifying the benefits of flow chemistry compared with conventional batch techniques. PMID:25484447

  6. Synthesis of (−)-Pseudotabersonine, (−)-Pseudovincadifformine, and (+)-Coronaridine Enabled by Photoredox Catalysis in Flow

    PubMed Central

    2015-01-01

    Natural product modification with photoredox catalysis allows for mild, chemoselective access to a wide array of related structures in complex areas of chemical space, providing the possibility for novel structural motifs as well as useful quantities of less abundant congeners. While amine additives have been used extensively as stoichiometric electron donors for photocatalysis, the controlled modification of amine substrates through single-electron oxidation is ideal for the synthesis and modification of alkaloids. Here, we report the conversion of the amine (+)-catharanthine into the natural products (−)-pseudotabersonine, (−)-pseudovincadifformine, and (+)-coronaridine utilizing visible light photoredox catalysis. PMID:25003992

  7. Catalysis for biomass and CO2 use through solar energy: opening new scenarios for a sustainable and low-carbon chemical production.

    PubMed

    Lanzafame, Paola; Centi, Gabriele; Perathoner, Siglinda

    2014-11-21

    The use of biomass, bio-waste and CO2 derived raw materials, the latter synthesized using H2 produced using renewable energy sources, opens new scenarios to develop a sustainable and low carbon chemical production, particularly in regions such as Europe lacking in other resources. This tutorial review discusses first this new scenario with the aim to point out, between the different possible options, those more relevant to enable this new future scenario for the chemical production, commenting in particular the different drivers (economic, technological and strategic, environmental and sustainability and socio-political) which guide the selection. The case of the use of non-fossil fuel based raw materials for the sustainable production of light olefins is discussed in more detail, but the production of other olefins and polyolefins, of drop-in intermediates and other platform molecules are also analysed. The final part discusses the role of catalysis in establishing this new scenario, summarizing the development of catalysts with respect to industrial targets, for (i) the production of light olefins by catalytic dehydration of ethanol and by CO2 conversion via FTO process, (ii) the catalytic synthesis of butadiene from ethanol, butanol and butanediols, and (iii) the catalytic synthesis of HMF and its conversion to 2,5-FDCA, adipic acid, caprolactam and 1,6-hexanediol.

  8. Pre-Steady State Studies of Phosphite Dehydrogenase Demonstrate that Hydride Transfer is Fully Rate-Limiting†

    PubMed Central

    Fogle, Emily J.

    2008-01-01

    Phosphite dehydrogenase (PTDH)1 is a unique NAD-dependent enzyme that catalyzes the oxidation of inorganic phosphite to phosphate. The enzyme has great potential for cofactor regeneration and mechanistic studies have provided some insight into the residues that are important for catalysis. In this investigation, pre-steady state studies were performed on the His6-tagged wild type (WT) enzyme, several active site mutants, a thermostable mutant (12X-PTDH), and a thermostable mutant with dual cofactor specificity (NADP-12X-PTDH). Stopped-flow kinetic experiments indicate that slow steps after hydride transfer do not significantly limit the rate of reaction for WT, the active site mutants, or the thermostable mutant. Pre-steady state kinetic isotope effects (KIEs) and single turn-over experiments further confirm that slow steps after the chemical step do not significantly limit the rate of reaction for any of these proteins. Collectively, these results suggest that the hydride transfer step is fully rate determining in PTDH and that the observed KIE on kcat is the intrinsic effect in WT PTDH and the mutants examined. In contrast, a slow step after catalysis may partially limit the rate of phosphite oxidation by NADP-12X-PTDH with NADP as cofactor. Finally, site directed mutagenesis of Asp79 indicates that this residue is important in orienting Arg237 for proper interaction with phosphite. PMID:17949110

  9. 103Rh NMR spectroscopy and its application to rhodium chemistry.

    PubMed

    Ernsting, Jan Meine; Gaemers, Sander; Elsevier, Cornelis J

    2004-09-01

    Rhodium is used for a number of large processes that rely on homogeneous rhodium-catalyzed reactions, for instance rhodium-catalyzed hydroformylation of alkenes, carbonylation of methanol to acetic acid and hydrodesulfurization of thiophene derivatives (in crude oil). Many laboratory applications in organometallic chemistry and catalysis involve organorhodium chemistry and a wealth of rhodium coordination compounds is known. For these and other areas, 103Rh NMR spectroscopy appears to be a very useful analytical tool. In this review, most of the literature concerning 103Rh NMR spectroscopy published from 1989 up to and including 2003 has been covered. After an introduction to several experimental methods for the detection of the insensitive 103Rh nucleus, a discussion of factors affecting the transition metal chemical shift is given. Computational aspects and calculations of chemical shifts are also briefly addressed. Next, the application of 103Rh NMR in coordination and organometallic chemistry is elaborated in more detail by highlighting recent developments in measurement and interpretation of 103Rh NMR data, in relation to rhodium-assisted reactions and homogeneous catalysis. The dependence of the 103Rh chemical shift on the ligands at rhodium in the first coordination sphere, on the complex geometry, oxidation state, temperature, solvent and concentration is treated. Several classes of compounds and special cases such as chiral rhodium compounds are reviewed. Finally, a section on scalar coupling to rhodium is provided. 2004 John Wiley & Sons, Ltd.

  10. Deacylation transition states of a bacterial DD-peptidase.

    PubMed

    Adediran, S A; Kumar, I; Pratt, R F

    2006-10-31

    Beta-lactam antibiotics restrict bacterial growth by inhibiting DD-peptidases. These enzymes catalyze the final transpeptidation step in bacterial cell wall biosynthesis. Although much structural information is now available for these enzymes, the mechanism of the actual transpeptidation reaction has not been studied in detail. The reaction is known to involve a double-displacement mechanism with an acyl-enzyme intermediate, which can be attacked by water, specific amino acids, peptides, and other acyl acceptors. We describe in this paper an investigation of acyl acceptor specificity and assess the need for general base catalysis in the deacylation transition state of the Streptomyces R61 DD-peptidase. We show, by the criterion of solvent deuterium kinetic isotope effect measurements and proton inventories, that the transition states of specific and nonspecific substrates are very similar, at least with respect to proton motion. The transition states for attack (tetrahedral intermediate formation) by d-amino acids and Gly-l-Xaa dipeptides do not include a general base catalyst, while such catalysis is essential for reaction with water and d-alpha-hydroxy acids. D-Alpha-hydroxy acids act as acyl acceptors for glycyl substrates but not for more specific d-alanyl substrates; hydroxy acids actually behave, more generally, as mixed inhibitors of the DD-peptidase. The structural and mechanistic bases of these observations are discussed; they should inform transition state analogue design.

  11. 77 FR 37284 - Technical Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-21

    ... DEPARTMENT OF LABOR Office of Workers' Compensation Programs 20 CFR Parts 701, 702, 703, 725, and 726 RIN 1240-AA05 Technical Amendments AGENCY: Office of Workers' Compensation Programs, Labor. ACTION: Final rule. SUMMARY: The Office of Workers' Compensation Programs is making [[Page 37285

  12. Vehicle infrastructure integration proof of concept : technical description--vehicle : final report

    DOT National Transportation Integrated Search

    2009-05-19

    This report provides the technical description of the VII system developed for the Cooperative Agreement VII Program between the USDOT and the VII Consortium. The basic architectural elements are summarized and detailed descriptions of the hardware a...

  13. Sustainable synthesis of chemical entities by microwave heating with nano-catalysis in water

    EPA Science Inventory

    •Sustainable synthesis of chemical entities by microwave heating with nano-catalysis in water •CRADA’s with the private companies, CEM corporation and VeruTEK Technologies •Green Chemistry principles are accommodated via multi-faceted approach. Learning from nature- using na...

  14. Mechanistic Enzyme Models: Pyridoxal and Metal Ions.

    ERIC Educational Resources Information Center

    Hamilton, S. E.; And Others

    1984-01-01

    Background information, procedures, and results are presented for experiments on the pyridoxal/metal ion model system. These experiments illustrate catalysis through Schiff's base formation between aldehydes/ketones and primary amines, catalysis by metal ions, and the predictable manner in which metal ions inhibit or catalyze reactions. (JN)

  15. An Acrobatic Substrate Metamorphosis Reveals a Requirement for Substrate Conformational Dynamics in Trypsin Proteolysis.

    PubMed

    Kayode, Olumide; Wang, Ruiying; Pendlebury, Devon F; Cohen, Itay; Henin, Rachel D; Hockla, Alexandra; Soares, Alexei S; Papo, Niv; Caulfield, Thomas R; Radisky, Evette S

    2016-12-16

    The molecular basis of enzyme catalytic power and specificity derives from dynamic interactions between enzyme and substrate during catalysis. Although considerable effort has been devoted to understanding how conformational dynamics within enzymes affect catalysis, the role of conformational dynamics within protein substrates has not been addressed. Here, we examine the importance of substrate dynamics in the cleavage of Kunitz-bovine pancreatic trypsin inhibitor protease inhibitors by mesotrypsin, finding that the varied conformational dynamics of structurally similar substrates can profoundly impact the rate of catalysis. A 1.4-Å crystal structure of a mesotrypsin-product complex formed with a rapidly cleaved substrate reveals a dramatic conformational change in the substrate upon proteolysis. By using long all-atom molecular dynamics simulations of acyl-enzyme intermediates with proteolysis rates spanning 3 orders of magnitude, we identify global and local dynamic features of substrates on the nanosecond-microsecond time scale that correlate with enzymatic rates and explain differential susceptibility to proteolysis. By integrating multiple enhanced sampling methods for molecular dynamics, we model a viable conformational pathway between substrate-like and product-like states, linking substrate dynamics on the nanosecond-microsecond time scale with large collective substrate motions on the much slower time scale of catalysis. Our findings implicate substrate flexibility as a critical determinant of catalysis. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. NetView technical research

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This is the Final Technical Report for the NetView Technical Research task. This report is prepared in accordance with Contract Data Requirements List (CDRL) item A002. NetView assistance was provided and details are presented under the following headings: NetView Management Systems (NMS) project tasks; WBAFB IBM 3090; WPAFB AMDAHL; WPAFB IBM 3084; Hill AFB; McClellan AFB AMDAHL; McClellan AFB IBM 3090; and Warner-Robins AFB.

  17. Inventory of greenhouse gas emissions from on-road vehicles in Midwestern USA States and integrated approach to achieving environmental sustainability in transportation : USDOT Region V Regional University Transportation Center final report : technical su

    DOT National Transportation Integrated Search

    2016-12-29

    Two project objectives one technical and one educational- were laid out in this project. The technical objective was to assess current inventory of greenhouse gases (GHG) in the six Midwestern states of the nation and to estimate improvements as ...

  18. Emissions Inventory Final Rule TSD

    EPA Pesticide Factsheets

    This technical support document (TSD) provides the details of emissions data processing done in support of EPA's final rulemaking effort for the Federal Transport Rule, now known as the Cross-State Air Pollution Rule.

  19. Heterogeneous Catalysis for Thermochemical Conversion | Bioenergy | NREL

    Science.gov Websites

    redox Ce-ZrO2 support. This article discusses research findings that appropriately frame the challenges to aid in bridging the findings of theoretical and experimental catalysis research, and transforming zeolite active site design from an empirical endeavor into a more predictable science founded on validated

  20. Surface Chemistry in Heterogeneous Catalysis: An Emerging Discipline.

    ERIC Educational Resources Information Center

    White, J. M.; Campbell, Charles T.

    1980-01-01

    Provides background data on surface chemistry as an emerging discipline. Highlights the important role which surfaces play in catalysis by focusing on the catalyzed oxidation of carbon monoxide. Provides a demonstration of how surfaces exert their influences in heterogeneous phenomena and illustrates how experimental problems in this field are…

  1. Appreciating Formal Similarities in the Kinetics of Homogeneous, Heterogeneous, and Enzyme Catalysis

    ERIC Educational Resources Information Center

    Ashby, Michael T.

    2007-01-01

    Because interest in catalysts is widespread, the kinetics of catalytic reactions have been investigated by widely diverse groups of individuals, including chemists, engineers, and biologists. This has lead to redundancy in theories, particularly with regard to the topics of homogeneous, heterogeneous, and enzyme catalysis. From a pedagogical…

  2. A Course in Heterogeneous Catalysis Involving Video-Based Seminars.

    ERIC Educational Resources Information Center

    White, Mark G.

    1984-01-01

    A video-based format was used during a graduate seminar course designed to educate students on the nature of catalysis, to help transfer information among students working on similar problems, and to improve communication skills. The mechanics of and student reaction to this seminar course are discussed. (JN)

  3. Homogeneous Catalysis by Transition Metal Compounds.

    ERIC Educational Resources Information Center

    Mawby, Roger

    1988-01-01

    Examines four processes involving homogeneous catalysis which highlight the contrast between the simplicity of the overall reaction and the complexity of the catalytic cycle. Describes how catalysts provide circuitous routes in which all energy barriers are relatively low rather than lowering the activation energy for a single step reaction.…

  4. Detection techniques for tenuous planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hoenig, S. A.

    1972-01-01

    The research for the development of new types of detectors for analysis of planetary atmospheres is summarized. Topics discussed include: corona discharge humidity detector, surface catalysis and exo-electron emission, and analysis of soil samples by means of exo-electron emission. A report on the exo-electron emission during heterogeneous catalysis is included.

  5. Transportation Network Data Requirements for Assessing Criticality for Resiliency and Adaptation Planning

    DOT National Transportation Integrated Search

    2017-11-01

    This report is one of two NCST Research Report documents produced as part of a project to advance the technical modeling tools for resiliency and adaptation planning, especially those used for criticality rankings. The official final technical report...

  6. Comment Deadlines Established Regarding the LightSquared Technical Working Group Report

    DOT National Transportation Integrated Search

    2011-06-30

    On June 30, 2011, LightSquared Subsidiary LLC (LightSquared) submitted a final report of the : technical working group co-chaired by LightSquared and the United States Global Positioning System : (GPS) Industry Council (USGIC)1 and organized in respo...

  7. Technical report on prototype intelligent network flow optimization (INFLO) dynamic speed harmonization and queue warning.

    DOT National Transportation Integrated Search

    2015-06-01

    This Technical Report on Prototype Intelligent Network Flow Optimization (INFLO) Dynamic Speed Harmonization and Queue Warning is the final report for the project. It describes the prototyping, acceptance testing and small-scale demonstration of the ...

  8. NUSC Technical Publications Guide.

    DTIC Science & Technology

    1985-05-01

    Facility personnel especially that of A. Castelluzzo, E. Deland, J. Gesel , and E. Szlosek (all of Code 4343). Reviewed and Approved: 14 July 1980 D...their technical content and format. Review and approve the manual outline, the review manuscript, and the final camera - reproducible copy. Conduct in

  9. Cross-State Air Pollution Rule Update Allowance Allocation Final Rule TSD

    EPA Pesticide Factsheets

    This Technical Support Document (TSD) provides information that supports EPA’s determination of unit-level allocations for existing and new units under the final Cross-State Air Pollution Rule Update.

  10. In-Situ Biocatalytic Production of Trehalose with Autoinduction Expression of Trehalose Synthase.

    PubMed

    Yan, Xincheng; Zhu, Liying; Yu, Yadong; Xu, Qing; Huang, He; Jiang, Ling

    2018-02-14

    We developed an in-situ biocatalytic process that couples autoinduction expression of trehalose synthase (TreS) and whole-cell catalysis for trehalose production. With lactose as the autoinducer, the activity of recombinant TreS in recombinant Escherichia coli was optimized through a visualization method, which resulted in a maximum value of 12 033 ± 730 U/mL in pH-stat fed-batch fermentation mode. Meanwhile, the permeability of the autoinduced E. coli increased significantly, which makes it possible to be directly used as a whole-cell biocatalyst for trehalose production, whereby the byproduct glucose can also act as an extra carbon source. In this case, the final yield of trehalose was improved to 90.5 ± 5.7% and remained as high as 83.2 ± 5.0% at the 10th batch, which is the highest value achieved using recombinant TreS. Finally, an integrated strategy for trehalose production was established, and its advantages compared to the traditional mode have been summarized.

  11. Guidelines for producing training films and videos.

    PubMed

    Harper, P B

    1991-01-01

    Drawing from experience in producing a film on the surgical procedure of female sterilization, 4 guidelines to technical film production for training purposes are presented and discussed in this paper. In order of presentation in the text, the paper 1st encourages identifying and securing a technical expert, then clearly identifying steps of the technical procedure, involving trainees and trainers in the production process, and working with experienced producers, scriptwriters, and crew members. Returning to the 1st guideline, the technical advisor will have a central presence during all photography and editing, and ideally should not have any personal investment in the procedure being shown. Prior to script finalization and sorting, research is urged to ensure concrete procedural steps. Printed materials, slides, interviews of experienced clinicians, procedure observation, and test videotape shooting may be called upon and employed as parts of the research phase. Trainees should participate during preliminary research, script development, and pretesting of early film versions, their suggestions for change incorporated where appropriate in the final version. On the final point of securing experienced workers, country nationals sensitive to relevant cultural and background dynamics should be included in the team. The special concerns of airport security regulation and customs requirements knowledge are essential, as well as their attention to assuring adequate on-site electricity for camera equipment.

  12. Northeast Corridor Improvement Project Electrification - New Haven, CT to Boston, MA : Final Environmental Statement/Report : v. 2. Technical Studies

    DOT National Transportation Integrated Search

    1994-10-31

    This document is the final environmental impact statement and final environmental impact report (FEIS/R) on the proposal by the National Railroad Passenger Corporation (Amtrak) to complete the electrification of the Northeast Corridor main line by ex...

  13. Health care fraud and abuse data collection program: technical revisions to Healthcare Integrity and Protection Data Bank data collection activities. Final rule.

    PubMed

    2004-09-21

    The rule finalizes technical changes to the Healthcare Integrity and Protection Data Bank (HIPDB) data collection reporting requirements by clarifying the types of personal numeric identifiers that may be reported to the data bank in connection with adverse actions. The rule clarifies that in lieu of a Social Security Number (SSN), an individual taxpayer identification number (ITIN) may be reported to the data bank when, in those limited situations, an individual does not have an SSN.

  14. Recovery Act-SmartGrid regional demonstration transmission and distribution (T&D) Infrastructure

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

    Hedges, Edward T.

    This document represents the Final Technical Report for the Kansas City Power & Light Company (KCP&L) Green Impact Zone SmartGrid Demonstration Project (SGDP). The KCP&L project is partially funded by Department of Energy (DOE) Regional Smart Grid Demonstration Project cooperative agreement DE-OE0000221 in the Transmission and Distribution Infrastructure application area. This Final Technical Report summarizes the KCP&L SGDP as of April 30, 2015 and includes summaries of the project design, implementation, operations, and analysis performed as of that date.

  15. Final Technical Report

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

    Sobecky, Patricia A; Taillefert, Martial

    This final technical report describes results and findings from a research project to examine the role of microbial phosphohydrolase enzymes in naturally occurring subsurface microorganisms for the purpose of promoting the immobilization of the radionuclide uranium through the production of insoluble uranium phosphate minerals. The research project investigated the microbial mechanisms and the physical and chemical processes promoting uranium biomineralization and sequestration in oxygenated subsurface soils. Uranium biomineralization under aerobic conditions can provide a secondary biobarrier strategy to immobilize radionuclides should the metal precipitates formed by microbial dissimilatory mechanisms remobilize due to a change in redox state.

  16. Waveguide Studies for Fiber Optics and Optical Signal Processing Applications.

    DTIC Science & Technology

    1980-04-01

    AO-A086 115 UNI!VERtSIT? OF SOUTIUR CALEPCRNA LOS AMUSS / 5 WAVGUIDE STUIES15 FOR FEB53 OpTECS AND OpTICAL SEOSA.o P /0Ksu-y "/6 UNLSIIDAPR N0 E...SAMUE Flola-??-c-sa UNCASZFIORAC-M-8042 U Final Technical Report (1 1April 1950 L V ~ WAVEGUIDE STUDIES FOR FIBER OPTICS AND OPTICAL SIGNAL PROCESSING...and Subtitle) 081 6&4𔃾JODO )EI YAVECUIDESTUDIES FOR JIBER OPTICS ANDL 7 Final ,T/echnical epoErt, OPTICAL SI’tNAL PROCESSING APPLICATIONS.4 11 Se 77

  17. SELECTIVE DISSEMINATION OF INFORMATION (SDI). VOLUME I, PILOT TEST AT U.S. ARMY NATICK LABORATORIES. FINAL REPORT. ARMY TECHNICAL LIBRARY IMPROVEMENT STUDIES (ATLIS), REPORT NO. 15.

    ERIC Educational Resources Information Center

    BIVONA, WILLIAM A.

    THIS VOLUME PRESENTS THE RESULTS OF A NINE-MONTH TEST OF A PROTOTYPE SELECTIVE DISSEMINATION OF INFORMATION (SDI) SYSTEM DEVELOPED FOR THE ARMY TECHNICAL LIBRARIES. DURING THE PILOT TEST ONE THOUSAND DOCUMENTS WERE CATALOGED, INDEXED, AND DISSEMINATED TO TWENTY-FIVE SCIENTIFIC AND TECHNICAL PERSONNEL. MATCHING OF THE INTEREST PROFILES OF THESE…

  18. Development of Molecular Catalysts to Bridge the Gap between Heterogeneous and Homogeneous Catalysts

    NASA Astrophysics Data System (ADS)

    Ye, Rong

    Catalysts, heterogeneous, homogeneous, and enzymatic, are comprised of nanometer-sized inorganic and/or organic components. They share molecular factors including charge, coordination, interatomic distance, bonding, and orientation of catalytically active atoms. By controlling the governing catalytic components and molecular factors, catalytic processes of a multichannel and multiproduct nature could be run in all three catalytic platforms to create unique end-products. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis. Recyclable catalysts, especially those that display selective reactivity, are vital for the development of sustainable chemical processes. Among available catalyst platforms, heterogeneous catalysts are particularly well-disposed toward separation from the reaction mixture via filtration methods, which renders them readily recyclable. Furthermore, heterogeneous catalysts offer numerous handles - some without homogeneous analogues - for performance and selectivity optimization. These handles include nanoparticle size, pore profile of porous supports, surface ligands and interface with oxide supports, and flow rate through a solid catalyst bed. Despite these available handles, however, conventional heterogeneous catalysts are themselves often structurally heterogeneous compared to homogeneous catalysts, which complicates efforts to optimize and expand the scope of their reactivity and selectivity. Ongoing efforts are aimed to address the above challenge by heterogenizing homogeneous catalysts, which can be defined as the modification of homogeneous catalysts to render them in a separable (solid) phase from the starting materials and products. Specifically, we grow the small nanoclusters in dendrimers, a class of uniform polymers with the connectivity of fractal trees and generally radial symmetry. Thanks to their dense multivalency, shape persistence and structural uniformity, dendrimers have proven to be versatile scaffolds for the synthesis and stabilization of small nanoclusters. Then these dendrimer-encapsulated metal clusters (DEMCs) are adsorbed onto mesoporous silica. Through this method, we have achieved selective transformations that had been challenging to accomplish in a heterogeneous setting, e.g. pi-bond activation and aldol reactions. Extensive investigation into the catalytic systems under reaction conditions allowed us to correlate the structural features (e.g. oxidation states) of the catalysts and their activity. Moreover, we have demonstrated that supported DEMCs are also excellent catalysts for typical heterogeneous reactions, including hydrogenation and alkane isomerization. Critically, these investigations also confirmed that the supported DEMCs are heterogeneous and stable against leaching. Catalysts optimization is achieved through the modulation of various parameters. The clusters are oxidized (e.g., with PhICl2) or reduced (e.g., with H2) in situ. Changing the dendrimer properties (e.g., generation, terminal functional groups) is analogous to ligand modification in homogeneous catalysts, which affect both catalytic activity and selectivity. Similarly, pore size of the support is another factor in determining product distribution. In a flow reactor, the flow rate is adjusted to control the residence time of the starting material and intermediates, and thus the final product selectivity. Our approach to heterogeneous catalysis affords various advantages: (1) the catalyst system can tap into the reactivity typical to homogeneous catalysts, which conventional heterogeneous catalysts could not achieve; (2) unlike most homogeneous catalysts with comparable performance, the heterogenized homogeneous catalysts can be recycled; (3) improved activity or selectivity compared to conventional homogeneous catalysts is possible because of uniquely heterogeneous parameters for optimization. While localized surface plasmon resonance (LSPR) provides a powerful platform for nanoparticle catalysis, our studies suggest that in some cases interband transitions should be considered as an alternative mechanism of light-driven nanoparticle catalysis. The benefits already demonstrated by plasmonic nanostructures as catalysts provided the impetus for examining complementary activation modes based on the metal nanoparticle itself. Leveraging these transitions has the potential to provide a means to highly active catalysis modes that would otherwise be challenging to access. For example, for the preparation of highly active metal catalysts on a subnanosized scale is challenging, thus limiting their exploitation and study in catalysis. Our work suggests a novel and facile strategy for the formation of highly active gold nanocluster catalysts by light illumination of the interband transitions in the presence of the appropriate substrate.

  19. Passion fruit-like nano-architectures: a general synthesis route

    NASA Astrophysics Data System (ADS)

    Cassano, D.; David, J.; Luin, S.; Voliani, V.

    2017-03-01

    Noble metal nanostructures have demonstrated a number of intriguing features for both medicine and catalysis. However, accumulation issues have prevented their clinical translation, while their use in catalysis has shown serious efficiency and stability hurdles. Here we introduce a simple and robust synthetic protocol for passion fruit-like nano-architectures composed by a silica shell embedding polymeric arrays of ultrasmall noble metal nanoparticles. These nano-architectures show interesting features for both oncology and catalysis. They avoid the issue of persistence in organism thanks to their fast biodegradation in renal clearable building blocks. Furthermore, their calcination results in yolk-shell structures composed by naked metal or alloy nanospheres shielded from aggregation by a silica shell.

  20. Supramolecular catalysis beyond enzyme mimics.

    PubMed

    Meeuwissen, Jurjen; Reek, Joost N H

    2010-08-01

    Supramolecular catalysis - the assembly of catalyst species by harnessing multiple weak intramolecular interactions - has, until recently, been dominated by enzyme-inspired approaches. Such approaches often attempt to create an enzyme-like 'active site' and have concentrated on reactions similar to those catalysed by enzymes themselves. Here, we discuss the application of supramolecular assembly to the more traditional transition metal catalysis and to small-molecule organocatalysis. The modularity of self-assembled multicomponent catalysts means that a relatively small pool of catalyst components can provide rapid access to a large number of catalysts that can be evaluated for industrially relevant reactions. In addition, we discuss how catalyst-substrate interactions can be tailored to direct substrates along particular reaction paths and selectivities.

  1. Heterobimetallic Catalysis: Platinum-Gold-Catalyzed Tandem Cyclization/C-X Coupling Reaction of (Hetero)Arylallenes with Nucleophiles.

    PubMed

    Alonso, José Miguel; Muñoz, María Paz

    2018-04-16

    Heterobimetallic catalysis offers new opportunities for reactivity and selectivity but still presents challenges, and only a few metal combinations have been explored so far. Reported here is a Pt-Au heterobimetallic catalyst system for the synthesis of a family of multi-heteroaromatic structures through tandem cyclization/C-X coupling reaction. Au-catalyzed 6-endo-cyclization takes place as the first fast step. Pt-Au clusters are proposed to be responsible for the increased reactivity in the second step, that is, the intermolecular nucleophilic addition which occurs through an outer-sphere mechanism by hybrid homogeneous-heterogeneous catalysis. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Passion fruit-like nano-architectures: a general synthesis route

    PubMed Central

    Cassano, D.; David, J.; Luin, S.; Voliani, V.

    2017-01-01

    Noble metal nanostructures have demonstrated a number of intriguing features for both medicine and catalysis. However, accumulation issues have prevented their clinical translation, while their use in catalysis has shown serious efficiency and stability hurdles. Here we introduce a simple and robust synthetic protocol for passion fruit-like nano-architectures composed by a silica shell embedding polymeric arrays of ultrasmall noble metal nanoparticles. These nano-architectures show interesting features for both oncology and catalysis. They avoid the issue of persistence in organism thanks to their fast biodegradation in renal clearable building blocks. Furthermore, their calcination results in yolk-shell structures composed by naked metal or alloy nanospheres shielded from aggregation by a silica shell. PMID:28256565

  3. Linear scaling relationships and volcano plots in homogeneous catalysis - revisiting the Suzuki reaction.

    PubMed

    Busch, Michael; Wodrich, Matthew D; Corminboeuf, Clémence

    2015-12-01

    Linear free energy scaling relationships and volcano plots are common tools used to identify potential heterogeneous catalysts for myriad applications. Despite the striking simplicity and predictive power of volcano plots, they remain unknown in homogeneous catalysis. Here, we construct volcano plots to analyze a prototypical reaction from homogeneous catalysis, the Suzuki cross-coupling of olefins. Volcano plots succeed both in discriminating amongst different catalysts and reproducing experimentally known trends, which serves as validation of the model for this proof-of-principle example. These findings indicate that the combination of linear scaling relationships and volcano plots could serve as a valuable methodology for identifying homogeneous catalysts possessing a desired activity through a priori computational screening.

  4. A nickel phosphine complex as a fast and efficient hydrogen production catalyst.

    PubMed

    Gan, Lu; Groy, Thomas L; Tarakeshwar, Pilarisetty; Mazinani, Shobeir K S; Shearer, Jason; Mujica, Vladimiro; Jones, Anne K

    2015-01-28

    Here we report the electrocatalytic reduction of protons to hydrogen by a novel S2P2 coordinated nickel complex, [Ni(bdt)(dppf)] (bdt = 1,2-benzenedithiolate, dppf = 1,1'-bis(diphenylphosphino)ferrocene). The catalysis is fast and efficient with a turnover frequency of 1240 s(-1) and an overpotential of only 265 mV for half activity at low acid concentrations. Furthermore, catalysis is possible using a weak acid, and the complex is stable for at least 4 h in acidic solution. Calculations of the system carried out at the density functional level of theory (DFT) are consistent with a mechanism for catalysis in which both protonations take place at the nickel center.

  5. Ceramic High Efficiency Particulate Air (HEPA) Filter Final Report CRADA No. TC02160.0

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

    Mitchell, M.; Bergman, W.

    2017-08-25

    The technical objective of this project was to develop a ceramic HEPA filter technology, by initially producing and testing coupon ceramics, small scale prototypes, and full scale prototype HEPA filters, and to address relevant manufacturing and commercialization technical issues.

  6. 7 CFR 614.6 - Agency records and decision notices.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... notifies participants of the agency's preliminary and final technical determinations and program decisions... decision notice within 10 working days of rendering a technical determination or program decision. In lieu of certified mail, NRCS may hand deliver notices to participants with written acknowledgment of...

  7. ECOS E-MATRIX Methane and Volatile Organic Carbon (VOC) Emissions Best Practices Database

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

    Parisien, Lia

    2016-01-31

    This final scientific/technical report on the ECOS e-MATRIX Methane and Volatile Organic Carbon (VOC) Emissions Best Practices Database provides a disclaimer and acknowledgement, table of contents, executive summary, description of project activities, and briefing/technical presentation link.

  8. 77 FR 18914 - National Motor Vehicle Title Information System (NMVTIS): Technical Corrections

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-29

    ... 1121-AA79 National Motor Vehicle Title Information System (NMVTIS): Technical Corrections AGENCY... (OJP) is promulgating this direct final rule for its National Motor Vehicle Title Information System... INFORMATION CONTACT paragraph. II. Background The National Motor Vehicle Title Information System was...

  9. Intelligent transportation system (ITS) study for the Buffalo and Niagara Falls metropolitan area, Erie and Niagara Counties, New York : final report, technical summary

    DOT National Transportation Integrated Search

    1997-06-18

    This document provides a technical summary for the seven working papers prepared for the New York State Department of Transportation (NYSDOT) Buffalo and Niagara Falls Intelligent Transportation System (ITS) Study.

  10. 77 FR 8095 - Technical Corrections to Commission Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-14

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission 18 CFR Part 2 [Docket No. RM11-30-000; Order No. 756] Technical Corrections to Commission Regulations Issued February 8, 2012. AGENCY: Federal Energy Regulatory Commission, DOE. ACTION: Final rule: correcting amendment. SUMMARY: This document adds...

  11. 78 FR 13543 - Defense Federal Acquisition Regulation Supplement; Technical Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-28

    ... DEPARTMENT OF DEFENSE Defense Acquisition Regulations System 48 CFR Parts 201, 204, 215, 225, 227, 242, 245, and 252 Defense Federal Acquisition Regulation Supplement; Technical Amendments AGENCY: Defense Acquisition Regulations System, Department of Defense (DoD). ACTION: Final rule. SUMMARY: DoD is...

  12. ENZVU--An Enzyme Kinetics Computer Simulation Based upon a Conceptual Model of Enzyme Action.

    ERIC Educational Resources Information Center

    Graham, Ian

    1985-01-01

    Discusses a simulation on enzyme kinetics based upon the ability of computers to generate random numbers. The program includes: (1) enzyme catalysis in a restricted two-dimensional grid; (2) visual representation of catalysis; and (3) storage and manipulation of data. Suggested applications and conclusions are also discussed. (DH)

  13. A Molecular Reaction Cycle with a Solvatochromic Merocyanine Dye: An Experiment in Photochemistry, Kinetics, and Catalysis.

    ERIC Educational Resources Information Center

    Abdel-Kader, M. H.; Steiner, U.

    1983-01-01

    Three experiments using merocyanine M suitable as an integrated laboratory experience for undergraduates are described. Experiments demonstrate: complete molecular cycle composed of photochemical, thermal, and protolytic reaction steps; kinetics of cis-trans isomerization of the dye; and mechanism of base catalysis for thermal isomerization of the…

  14. Let There Be Light: Hypothesis-Driven Investigation of Ligand Effects in Photoredox Catalysis for the Undergraduate Organic Chemistry Laboratory

    ERIC Educational Resources Information Center

    Chen, Shuming

    2018-01-01

    An undergraduate organic chemistry laboratory experiment that provides an introduction to the concepts and practices of photoredox catalysis is reported. While undergraduate-level photochemistry experiments typically place emphasis on analytical properties of catalysts rather than synthetic applications, this experiment showcases the power and…

  15. Catalysis and Multi-Component Reactions

    NASA Astrophysics Data System (ADS)

    Shibasaki, Masakatsu; Yus, Miguel; Bremner, Stacy; Comer, Eamon; Shore, Gjergji; Morin, Sylvie; Organ, Michael G.; van der Eycken, Erik; Merkul, Eugen; Dorsch, Dieter; Müller, Thomas J. J.; Ryabukhin, Sergey V.; Ostapchuk, Eugeniy N.; Plaskon, Andrey S.; Volochnyuk, Dmitriy M.; Shivanyuk, Alexander N.; Tolmachev, Andrey A.; Sheibani, Hassan; Babaie, Maryam; Behzadi, Soheila; Dabiri, Minoo; Bahramnejad, Mahboobeh; Bashiribod, Sahareh; Hekmatshoar, Rahim; Sadjadi, Sodeh; Khorasani, Mohammad; Polyakov, Anatoliy I.; Eryomina, Vera A.; Medvedeva, Lidiya A.; Tihonova, Nadezhda I.; Listratova, Anna V.; Voskressensky, Leonid G.; Merkul, Eugen; Dorsch, Dieter; Müller, Thomas J. J.; Sheibani, Hassan; Esfandiarpoor, Zeinab; Behzadi, Soheila; Titova, Julia A.; Fedorova, Olga V.; Ovchinnikova, Irina G.; Valova, Marina S.; Koryakova, Olga V.; Rusinov, Gennady L.; Charushin, Valery N.; Hekmatshoar, Rahim; Sadjadi, Sodeh

    We have been studying the development of new asymmetric two-center catalysis using rare earth alkoxides and bifunctional sugar and related ligands. In The Fourth International Conference on Multi-Component Reactions and Related Chemistry (MCR 2009), new catalytic asymmetric reactions using catalysts 1 and 2 and catalytic asymmetric syntheses of ranirestat 3 and tamiflu 4 will be presented.

  16. Preparation of starch-sodium lignosulfonate graft copolymers via laccase catalysis and characterization of antioxidant activity

    USDA-ARS?s Scientific Manuscript database

    Graft copolymers of waxy maize starch and sodium lignosulfonate (SLS) were prepared by Trametes Versicolor laccase catalysis in aqueous solution. Amount of SLS grafted based on phenol analysis was 0.5% and 1.0% in the absence and presence of 1-hydroxybenzotriazole (HBT), respectively. Starch-SLS gra...

  17. Substrate-Tuned Catalysis of the Radical S-Adenosyl-L-Methionine Enzyme NosL Involved in Nosiheptide Biosynthesis.

    PubMed

    Ji, Xinjian; Li, Yongzhen; Ding, Wei; Zhang, Qi

    2015-07-27

    NosL is a radical S-adenosyl-L-methionine (SAM) enzyme that converts L-Trp to 3-methyl-2-indolic acid, a key intermediate in the biosynthesis of a thiopeptide antibiotic nosiheptide. In this work we investigated NosL catalysis by using a series of Trp analogues as the molecular probes. Using a benzofuran substrate 2-amino-3-(benzofuran-3-yl)propanoic acid (ABPA), we clearly demonstrated that the 5'-deoxyadenosyl (dAdo) radical-mediated hydrogen abstraction in NosL catalysis is not from the indole nitrogen but likely from the amino group of L-Trp. Unexpectedly, the major product of ABPA is a decarboxylated compound, indicating that NosL was transformed to a novel decarboxylase by an unnatural substrate. Furthermore, we showed that, for the first time to our knowledge, the dAdo radical-mediated hydrogen abstraction can occur from an alcohol hydroxy group. Our study demonstrates the intriguing promiscuity of NosL catalysis and highlights the potential of engineering radical SAM enzymes for novel activities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Thumb-loops up for catalysis: a structure/function investigation of a functional loop movement in a GH11 xylanase

    PubMed Central

    Paës, Gabriel; Cortés, Juan; Siméon, Thierry; O'Donohue, Michael J.; Tran, Vinh

    2012-01-01

    Dynamics is a key feature of enzyme catalysis. Unfortunately, current experimental and computational techniques do not yet provide a comprehensive understanding and description of functional macromolecular motions. In this work, we have extended a novel computational technique, which combines molecular modeling methods and robotics algorithms, to investigate functional motions of protein loops. This new approach has been applied to study the functional importance of the so-called thumb-loop in the glycoside hydrolase family 11 xylanase from Thermobacillus xylanilyticus (Tx-xyl). The results obtained provide new insight into the role of the loop in the glycosylation/deglycosylation catalytic cycle, and underline the key importance of the nature of the residue located at the tip of the thumb-loop. The effect of mutations predicted in silico has been validated by in vitro site-directed mutagenesis experiments. Overall, we propose a comprehensive model of Tx-xyl catalysis in terms of substrate and product dynamics by identifying the action of the thumb-loop motion during catalysis. PMID:24688637

  19. Alternatives for Jet Engine Control. Volume 1: Modelling and Control Design with Jet Engine Data

    NASA Technical Reports Server (NTRS)

    Sain, M. K.

    1985-01-01

    This document compiles a comprehensive list of publications supported by, or related to, National Aeronautics and Space Administration Grant NSG-3048, entitled "Alternatives for Jet Engine Control". Dr. Kurt Seldner was the original Technical Officer for the grant, at Lewis Research Center. Dr. Bruce Lehtinen was the final Technical Officer. At the University of Notre Dame, Drs. Michael K. Sain and R. Jeffrey Leake were the original Project Directors, with Dr. Sain becoming the final Project Director. Publications cover work over a ten-year period. The Final Report is divided into two parts. Volume i, "Modelling and Control Design with Jet Engine Data", follows in this report. Volume 2, "Modelling and Control Design with Tensors", has been bound separately.

  20. Dynamically achieved active site precision in enzyme catalysis.

    PubMed

    Klinman, Judith P

    2015-02-17

    CONSPECTUS: The grand challenge in enzymology is to define and understand all of the parameters that contribute to enzymes' enormous rate accelerations. The property of hydrogen tunneling in enzyme reactions has moved the focus of research away from an exclusive focus on transition state stabilization toward the importance of the motions of the heavy atoms of the protein, a role for reduced barrier width in catalysis, and the sampling of a protein conformational landscape to achieve a family of protein substates that optimize enzyme-substrate interactions and beyond. This Account focuses on a thermophilic alcohol dehydrogenase for which the chemical step of hydride transfer is rate determining across a wide range of experimental conditions. The properties of the chemical coordinate have been probed using kinetic isotope effects, indicating a transition in behavior below 30 °C that distinguishes nonoptimal from optimal C-H activation. Further, the introduction of single site mutants has the impact of either enhancing or eliminating the temperature dependent transition in catalysis. Biophysical probes, which include time dependent hydrogen/deuterium exchange and fluorescent lifetimes and Stokes shifts, have also been pursued. These studies allow the correlation of spatially resolved transitions in protein motions with catalysis. It is now possible to define a long-range network of protein motions in ht-ADH that extends from a dimer interface to the substrate binding domain across to the cofactor binding domain, over a distance of ca. 30 Å. The ongoing challenge to obtaining spatial and temporal resolution of catalysis-linked protein motions is discussed.

  1. Design of a new reactor-like high temperature near ambient pressure scanning tunneling microscope for catalysis studies.

    PubMed

    Tao, Franklin Feng; Nguyen, Luan; Zhang, Shiran

    2013-03-01

    Here, we present the design of a new reactor-like high-temperature near ambient pressure scanning tunneling microscope (HT-NAP-STM) for catalysis studies. This HT-NAP-STM was designed for exploration of structures of catalyst surfaces at atomic scale during catalysis or under reaction conditions. In this HT-NAP-STM, the minimized reactor with a volume of reactant gases of ∼10 ml is thermally isolated from the STM room through a shielding dome installed between the reactor and STM room. An aperture on the dome was made to allow tip to approach to or retract from a catalyst surface in the reactor. This dome minimizes thermal diffusion from hot gas of the reactor to the STM room and thus remains STM head at a constant temperature near to room temperature, allowing observation of surface structures at atomic scale under reaction conditions or during catalysis with minimized thermal drift. The integrated quadrupole mass spectrometer can simultaneously measure products during visualization of surface structure of a catalyst. This synergy allows building an intrinsic correlation between surface structure and its catalytic performance. This correlation offers important insights for understanding of catalysis. Tests were done on graphite in ambient environment, Pt(111) in CO, graphene on Ru(0001) in UHV at high temperature and gaseous environment at high temperature. Atom-resolved surface structure of graphene on Ru(0001) at 500 K in a gaseous environment of 25 Torr was identified.

  2. 48 CFR 252.235-7011 - Final scientific or technical report.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... technical report. 252.235-7011 Section 252.235-7011 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT... of the report; and (c) For submission of reports in other than paper copy, contact the Defense...

  3. 48 CFR 252.235-7011 - Final scientific or technical report.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... technical report. 252.235-7011 Section 252.235-7011 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT... of the report; and (c) For submission of reports in other than paper copy, contact the Defense...

  4. 48 CFR 252.235-7011 - Final scientific or technical report.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... technical report. 252.235-7011 Section 252.235-7011 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT... of the report; and (c) For submission of reports in other than paper copy, contact the Defense...

  5. 48 CFR 252.235-7011 - Final scientific or technical report.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... technical report. 252.235-7011 Section 252.235-7011 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT... of the report; and (c) For submission of reports in other than paper copy, contact the Defense...

  6. 48 CFR 252.235-7011 - Final scientific or technical report.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... technical report. 252.235-7011 Section 252.235-7011 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT... of the report; and (c) For submission of reports in other than paper copy, contact the Defense...

  7. Vocational Outreach Involving Community Exchange (VOICE). Final Report.

    ERIC Educational Resources Information Center

    Huckabee, Johnni

    A Jonesboro, Arkansas project was designed and implemented to increase the awareness of vocational education, increase community support and involvement in vocational education, and establish improved communication in the vocational-technical education field. Interaction between the vocational-technical school and the local school community was a…

  8. Bimetallic redox synergy in oxidative palladium catalysis.

    PubMed

    Powers, David C; Ritter, Tobias

    2012-06-19

    Polynuclear transition metal complexes, which are embedded in the active sites of many metalloenzymes, are responsible for effecting a diverse array of oxidation reactions in nature. The range of chemical transformations remains unparalleled in the laboratory. With few noteworthy exceptions, chemists have primarily focused on mononuclear transition metal complexes in developing homogeneous catalysis. Our group is interested in the development of carbon-heteroatom bond-forming reactions, with a particular focus on identifying reactions that can be applied to the synthesis of complex molecules. In this context, we have hypothesized that bimetallic redox chemistry, in which two metals participate synergistically, may lower the activation barriers to redox transformations relevant to catalysis. In this Account, we discuss redox chemistry of binuclear Pd complexes and examine the role of binuclear intermediates in Pd-catalyzed oxidation reactions. Stoichiometric organometallic studies of the oxidation of binuclear Pd(II) complexes to binuclear Pd(III) complexes and subsequent C-X reductive elimination from the resulting binuclear Pd(III) complexes have confirmed the viability of C-X bond-forming reactions mediated by binuclear Pd(III) complexes. Metal-metal bond formation, which proceeds concurrently with oxidation of binuclear Pd(II) complexes, can lower the activation barrier for oxidation. We also discuss experimental and theoretical work that suggests that C-X reductive elimination is also facilitated by redox cooperation of both metals during reductive elimination. The effect of ligand modification on the structure and reactivity of binuclear Pd(III) complexes will be presented in light of the impact that ligand structure can exert on the structure and reactivity of binuclear Pd(III) complexes. Historically, oxidation reactions similar to those discussed here have been proposed to proceed via mononuclear Pd(IV) intermediates, and the hypothesis of mononuclear Pd(II/IV) catalysis has guided the successful development of many reactions. Herein we discuss differences between monometallic Pd(IV) and bimetallic Pd(III) redox catalysis. We address whether appreciation of the relevance of bimetallic Pd(III) redox catalysis is of academic interest exclusively, serving to provide a more nuanced description of catalysis, or if the new insight regarding bimetallic Pd(III) chemistry can be a platform to enable future reaction development. To this end, we describe an example in which the hypothesis of bimetallic redox chemistry guided reaction development, leading to the discovery of reactivity distinct from monometallic catalysts.

  9. Molecular-Level Design of Heterogeneous Chiral Catalysis

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

    Francisco Zaera

    2012-03-21

    The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by formingmore » naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to be funded by the monies requested in this proposal, is to apply those methods to specific problems in chiral catalysis, including the identification of the requirements for the formation of supramolecular surface structures with enantioselective behavior, the search for better molecules to probe the chiral nature of the modified surfaces, the exploration of the transition from supramolecular to one-to-one chiral modification, the correlation of the adsorption characteristics of one-to-one chiral modifiers with their physical properties, in particular with their configuration, and the development of ways to imprint chiral centers on achiral solid surfaces. Chiral catalysis is not only a problem of great importance in its own right, but also the ultimate test of how to control selectivity in catalysis. The time is ripe for fundamental work in heterogeneous chiral catalysis to provide the U.S. with a leadership role in developing the next generation of catalytic processes for medicinal and agrochemical manufacturing. Our team provides the required expertise for a synergistic and comprehensive integration of physical and chemical experimentation with solid state and molecular reactivity theories to solve this problem.« less

  10. Is It Homogeneous or Heterogeneous Catalysis Derived from [RhCp*Cl2]2? In Operando-XAFS, Kinetic and Crucial Kinetic Poisoning Evidence for Subnanometer Rh4 Cluster-Based Benzene Hydrogenation Catalysis

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

    Bayram, Ercan; Linehan, John C.; Fulton, John L.

    2011-11-23

    Determining the true, kinetically dominant catalytically active species, in the classic benzene hydrogenation system pioneered by Maitlis and co-workers 34 years ago starting with [RhCp*Cl2]2 (Cp* = [{eta}5-C5(CH3)5]), has proven to be one of the most challenging case studies in the quest to distinguish single-metal-based 'homogeneous' from polymetallic, 'heterogeneous' catalysis. The reason, this study will show, is the previous failure to use the proper combination of (i) operando spectroscopy to determine the dominant form(s) of the precatalyst's mass under catalysis (i.e., operating) conditions, plus then and crucially also (ii) the previous lack of the necessary kinetic studies, catalysis being amore » 'wholly kinetic phenomenon' as J. Halpern long ago noted. An important contribution from this study will be to reveal the power of quantitiative kinetic poisoning experiments for distinguishing single-metal, or in this case subnanometer Rh4 cluster-based catalysis from larger, polymetallic Rh(0)n nanoparticle catalysis, at least under favorable conditions. The combined operando-XAFS (X-ray absorption fine structure) spectroscopy and kinetic evidences provide a compelling case for Rh4-based, with average stoichiometry 'Rh4Cp*2.4Cl4Hc', benzene hydrogenation catalysis in 2-propanol with added Et3N and at 100 C and 50 atm initial H2 pressure. The results also reveal, however, that if even ca. 1.4% of the total soluble Rh(0)n had formed nanoparticles, then those Rh(0)n nanoparticles would have been able to account for all the observed benzene hydrogenation catalytic rate (using commercial, ca. 2 nm, polyethyleneglycol-dodecylether hydrosol stabilized Rh(0)n nanoparticles as a model system). The results 'especially the poisoning methodology developed and employed' are of significant, broader interest since determining the nature of the true catalyst continues to be a central, often vexing issue in any and all catalytic reactions. The results are also of fundamental interest in that they add to a growing body of evidence indicating that certain, appropriately ligated, coordinatively unsaturated, subnanometer M4 transition-metal clusters can be relatively robust catalysts. Also demonstrated herein is that Rh4 clusters are poisoned by Hg(0), demonstrating for the first time that the classic Hg(0) poisoning test of 'homogeneous' vs 'heterogeneous'catalysts cannot distinguish Rh4-based subnanometer catalysts from Rh(0)n nanoparticle catalysts, at least for the present examples of these two specific, Rh-based catalysts.« less

  11. Merging Visible Light Photoredox Catalysis with Metal Catalyzed C–H Activations: On the Role of Oxygen and Superoxide Ions as Oxidants

    PubMed Central

    2016-01-01

    Conspectus The development of efficient catalytic systems for direct aromatic C–H bond functionalization is a long-desired goal of chemists, because these protocols provide environmental friendly and waste-reducing alternatives to classical methodologies for C–C and C–heteroatom bond formation. A key challenge for these transformations is the reoxidation of the in situ generated metal hydride or low-valent metal complexes of the primary catalytic bond forming cycle. To complete the catalytic cycle and to regenerate the C–H activation catalyst, (super)stoichiometric amounts of Cu(II) or Ag(I) salts have often been applied. Recently, “greener” approaches have been developed by applying molecular oxygen in combination with Cu(II) salts, internal oxidants that are cleaved during the reaction, or solvents or additives enabling the metal hydride reoxidation. All these approaches improved the environmental friendliness but have not overcome the obstacles associated with the overall limited functional group and substrate tolerance. Hence, catalytic processes that do not feature the unfavorable aspects described above and provide products in a streamlined as well as economically and ecologically advantageous manner would be desirable. In this context, we decided to examine visible light photoredox catalysis as a new alternative to conventionally applied regeneration/oxidation procedures. This Account summarizes our recent advances in this expanding area and will highlight the new concept of merging distinct redox catalytic processes for C–H functionalizations through the application of visible light photoredox catalysis. Photoredox catalysis can be considered as catalytic electron-donating or -accepting processes, making use of visible-light absorbing homogeneous and heterogeneous metal-based catalysts, as well as organic dye sensitizers or polymers. As a consequence, photoredox catalysis is, in principle, an ideal tool for the recycling of any given metal catalyst via a coupled electron transfer (ET) process. Here we describe our first successful endeavors to address the above challenges by combining visible light photoredox catalysis with different ruthenium, rhodium, or palladium catalyzed C–H activations. Since only small amounts of the oxidant are generated and are immediately consumed in these transformations, side reactions of substrates or products can be avoided. Thus, usually oxidant-sensible substrates can be used, which makes these methods highly suitable for complex molecular structure syntheses. Moreover, mechanistic studies shed light on new reaction pathways, intermediates, and in situ generated species. The successful development of our dual catalysis concept, consisting of combined visible light photoredox catalysis and metal catalyzed C–H functionalization, provides many new opportunities for further explorations in the field of C–H functionalization. PMID:27556812

  12. King County Metro Transit Hybrid Articulated Buses: Final Evaluation Results

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

    Chandler, K.; Walkowicz, K.

    2006-12-01

    Final technical report compares and evaluates new diesel and diesel hybrid-electric articulated buses operated as part of the King County Metro Transit (KC Metro) fleet in Seattle, Washington. The evaluation lasted 12 months.

  13. 78 FR 1143 - Explosive Siting Requirements; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-08

    ... launch site operators in site planning for the storage and handling of energetic liquids and explosives...: For technical questions concerning this final rule, contact Yvonne Tran, Commercial Space... this final rule, contact Laura Montgomery, AGC 200, [[Page 1144

  14. Final June Revisions Rule State Budgets and New Unit Set-Asides TSD

    EPA Pesticide Factsheets

    This technical support document (TSD) for the final revisions to the Transport Rule shows the underlying data and calculations used to quantify the state budget revisions and new unit set-aside revisions.

  15. Department of Defense Access to Intellectual Property for Weapon Systems Sustainment

    DTIC Science & Technology

    2017-05-01

    and acquiring technical data rights …  The cost benefit analysis of including a priced contract option for the future delivery of technical data...entail in terms of cost and benefits , while one of the activities to be finalized is the contract-specific technical data elements.66...Virginia 22311-1882 May 2017 Approved for public release; distribution is unlimited. IDA Paper P-8266 Log: H 17-000030 About This Publication This

  16. 10 CFR 51.92 - Supplement to the final environmental impact statement.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... changes in the proposed action that are relevant to environmental concerns; or (2) There are new and..., technical, and other benefits and costs of the proposed action, to the extent that the final environmental... costs; (5) Include an analysis of other energy alternatives, to the extent that the final environmental...

  17. Dissemination of Continuing Education Materials Via Television Delivery Systems. Final Technical Report and Final Report.

    ERIC Educational Resources Information Center

    Munushian, Jack

    In 1972, the University of Southern California School of Engineering established a 4-channel interactive instructional television network. It was designed to allow employees of participating industries to take regular university science and engineering courses and special continuing education courses at or near their work locations. Final progress…

  18. The role of non-technical skills in surgery

    PubMed Central

    Agha, Riaz A.; Fowler, Alexander J.; Sevdalis, Nick

    2015-01-01

    Non-technical skills are of increasing importance in surgery and surgical training. A traditional focus on technical skills acquisition and competence is no longer enough for the delivery of a modern, safe surgical practice. This review discusses the importance of non-technical skills and the values that underpin successful modern surgical practice. This narrative review used a number of sources including written and online, there was no specific search strategy of defined databases. Modern surgical practice requires; technical and non-technical skills, evidence-based practice, an emphasis on lifelong learning, monitoring of outcomes and a supportive institutional and health service framework. Finally these requirements need to be combined with a number of personal and professional values including integrity, professionalism and compassionate, patient-centred care. PMID:26904193

  19. Recent Advances in Preparation, Structure, Properties and Applications of Graphite Oxide.

    PubMed

    Srivastava, Suneel Kumar; Pionteck, Jürgen

    2015-03-01

    Graphite oxide, also referred as graphitic oxide or graphitic acid, is an oxidized bulk product of graphite with a variable composition. However, it did not receive immense attention until it was identified as an important and easily obtainable precursor for the preparation of graphene. This inspired many researchers to explore facts related to graphite oxide in exploiting its fascinating features. The present article culminates up-dated review on different preparative methods, morphology and characterization of physical/chemical properties of graphite oxide by XRD, XPS, FTIR, Raman, NMR, UV-visible, and DRIFT analyses. Finally, recent developments on intercalation and applications of GO in multifaceted areas of catalysis, sensor, supercapacitors, water purification, hydrogen storage and magnetic shielding etc. has also been reviewed.

  20. Heterogeneous Catalysis: On Bathroom Mirrors and Boiling Stones

    ERIC Educational Resources Information Center

    Philipse, Albert P.

    2011-01-01

    Though heterogeneous nucleation of liquid droplets on a smooth surface (such as a bathroom mirror) is a classical topic in nucleation theory, it is not well-known that this topic is actually a pedagogical example of heterogeneous catalysis: the one and only effect of the surface is to lower the activation Gibbs energy of droplet formation. In…

  1. Electrophilic activation of alkynes for enyne cycloisomerization reactions with in situ generated early/late heterobimetallic Pt-Ti catalysts.

    PubMed

    Talley, Michael R; Stokes, Ryjul W; Walker, Whitney K; Michaelis, David J

    2016-06-14

    In situ formation of heterobimetallic Pt-Ti catalysts enables rapid room temperature catalysis in enyne cycloisomerization reactions. The Lewis acidic titanium atom in the ligand framework is shown to be essential for fast catalysis. A range of enyne substrates are efficiently cyclized to carbocycles and heterocycles in high yield.

  2. Heterogeneous Catalysis: A Central Science for a Sustainable Future.

    PubMed

    Friend, Cynthia M; Xu, Bingjun

    2017-03-21

    Developing active, selective, and energy efficient heterogeneous catalytic processes is key to a sustainable future because heterogeneous catalysis is at the center of the chemicals and energy industries. The design, testing, and implementation of robust and selective heterogeneous catalytic processes based on insights from fundamental studies could have a tremendous positive impact on the world.

  3. Diphenylbutadienes Syntheses by Means of the Wittig Reaction: Experimental Introduction to the Use of Phase Transfer Catalysis.

    ERIC Educational Resources Information Center

    Gillois, J.; And Others

    1980-01-01

    The synthesis of 1,4-diphenylbutadiene by means of the Wittig reaction is presented as suitable for organic chemistry students at the end of a basic laboratory program to apply laboratory skills and display understanding of the use of phase transfer catalysis and its application in syntheses. (CS)

  4. Pop-It Beads to Introduce Catalysis of Reaction Rate and Substrate Depletion Effects

    ERIC Educational Resources Information Center

    Gehret, Austin U.

    2017-01-01

    A kinesthetic classroom activity was designed to help students understand enzyme activity and catalysis of reaction rate. Students served the role of enzymes by manipulating Pop-It Beads as the catalytic event. This activity illuminates the relationship between reaction rate and reaction progress by allowing students to experience first-hand the…

  5. α-Arylation/Heteroarylation of Chiral α-Aminomethyltrifluoroborates by Synergistic Iridium Photoredox/Nickel Cross-Coupling Catalysis.

    PubMed

    El Khatib, Mirna; Serafim, Ricardo Augusto Massarico; Molander, Gary A

    2016-01-04

    Direct access to complex, enantiopure benzylamine architectures using a synergistic iridium photoredox/nickel cross-coupling dual catalysis strategy has been developed. New C(sp(3))-C(sp(2)) bonds are forged starting from abundant and inexpensive natural amino acids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. 75 FR 16345 - Administrative Practices and Procedures; Good Guidance Practices; Technical Amendment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-01

    .... FDA-1999-N-3539] (formerly Docket No. 1999N-4783) Administrative Practices and Procedures; Good Guidance Practices; Technical Amendment AGENCY: Food and Drug Administration, HHS. ACTION: Final rule... Subjects in 21 CFR Part 10 Administrative practice and procedure, News media. 0 Therefore, under the...

  7. Final report : for the period of December 1999 through November 30, 2000 : Florida Transit Training Program (1999/2000) : Florida Technical Assistance Program (1999/2000)

    DOT National Transportation Integrated Search

    2000-01-01

    The following progress report is intended to highlight the significant activities of the Florida Transit Training Program and Florida Technical Assistant Program. The following progress report is intended to highlight the significant activities of th...

  8. 78 FR 34264 - Technical Corrections to the HIPAA Privacy, Security, and Enforcement Rules

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ...-AA03 Technical Corrections to the HIPAA Privacy, Security, and Enforcement Rules AGENCY: Office for... corrections address certain inadvertent errors and omissions in the HIPAA Privacy, Security, and Enforcement... (HHS or ``the Department'') published a final rule to implement changes to the HIPAA Privacy, Security...

  9. 76 FR 11414 - Defense Federal Acquisition Regulation Supplement; Independent Research and Development Technical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-02

    ... Acquisition Regulation Supplement; Independent Research and Development Technical Descriptions (DFARS Case... (DFARS) to require contractors to report independent research and development (IR&D) projects generating... the address shown below on or before May 2, 2011, to be considered in the formation of the final rule...

  10. Professional Personnel Evaluation System: 1983-84 Final Technical Report.

    ERIC Educational Resources Information Center

    Doss, David A.

    This technical report summarizes the evaluation ratings given to professionals on probation or up for contract renewal in the Austin Independent School District. Graphs, tables, and rankings are presented for each specified population: all district teachers combined; teachers by school level (elementary, junior high, senior high); teachers by…

  11. High School Graduation Minimum Competency Requirements. Final Technical Report.

    ERIC Educational Resources Information Center

    Austin Independent School District, TX. Office of Research and Evaluation.

    This technical report details the testing results and analyses supporting the evaluation findings related to the Austin (Texas) Independent School District (AISD) minimum competency graduation requirements. The graduation competency status of all AISD students in grades 8 to 12 are documented. The report provides additional information on the data…

  12. 76 FR 16531 - Technical Correction for Neurological Listing Cross-Reference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-24

    ... 1-800-325-0778, or visit our Internet site, Social Security Online, at http://www.socialsecurity.gov... SOCIAL SECURITY ADMINISTRATION 20 CFR Part 404 [Docket No. SSA-2011-0019] RIN 0960-AH33 Technical Correction for Neurological Listing Cross-Reference AGENCY: Social Security Administration. ACTION: Final...

  13. Improving Vocational Education in Post-High School Institutions. Final Report.

    ERIC Educational Resources Information Center

    MacArthur, Earl W.

    Four ongoing programs in postsecondary vocational-technical education were examined in a national institute attended by 59 representatives from 31 states. Institutions reporting programs were: (1) Los Angeles Trade and Technical College, California, (2) Washtenaw Community College, Ann Arbor, Michigan, (3) Rockingham Community College, Wentworth,…

  14. Chicago Manufacturing Tech Prep. Fiscal Year 1991 Final Report.

    ERIC Educational Resources Information Center

    Chicago City Colleges, IL.

    During its first year of development in 1991, the Chicago Manufacturing Technical Preparation (Tech Prep) Program established a plan for implementing an industry-driven, articulated 4-year manufacturing technology course of study that integrates applied academic courses with technical courses and meets industry hiring standards. The project…

  15. 78 FR 29239 - Final Priority; Technical Assistance To Improve State Data Capacity-National Technical Assistance...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-20

    ... reporting requirements. Changes: None. Focus TA on Assessment and Discipline Data Comment: Three commenters agreed with the importance of focusing on assessment and discipline data, and two commenters agreed with... decisions and actions associated with data collection and reporting. One commenter stated that assessment...

  16. Modular Radioisotope Thermoelectric Generator (RTG) Program. Final technical report

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

    Not Available

    1992-12-31

    Section 2.0 of this report summarizes the MOD-RTG reference flight design, and Section 3.0 discusses the Ground Demonstration System design. Multicouple technology development is discussed in Section 4.0, and Section 5.0 lists all published technical papers prepared during the course of the contract.

  17. Methodology in Seeking Stakeholder Perceptions of Effective Technical Oral Presentations: An Exploratory Pilot Study

    ERIC Educational Resources Information Center

    Bhattacharyya, Ena; Patil, Arun; Sargunan, Rajeswary Appacutty

    2010-01-01

    Engineering communication studies indicate the importance of oral presentations as an indispensable component of workplace oral communication activities; however, since there is limited literature regarding stakeholder perceptions of effective presentation skills and attributes in technical oral presentations or final year engineering project…

  18. Additional Final Area Designations and Technical Amendment for the 2012 Annual Fine Particle Standard Established in 2012 - Mar 2015

    EPA Pesticide Factsheets

    EPA is establishing or revising initial area designations and a technical amendment to correct an inadvertent error in the initial designation for one area for the 2012 annual national ambient air quality standards for fine particle pollution.

  19. 75 FR 41404 - List of Approved Spent Fuel Storage Casks: NUHOMS®

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-16

    .... The NRC is taking this action because the applicant identified that a certain Technical Specification (TS) for Boral characterization was not written precisely. Specifically, the requirements for meeting... changes to the technical specifications. The NRC also published a direct final rule on May 6, 2010 (75 FR...

  20. Research in Automatic Russian-English Scientific and Technical Lexicography. Final Report.

    ERIC Educational Resources Information Center

    Wayne State Univ., Detroit, MI.

    Techniques of reversing English-Russian scientific and technical dictionaries into Russian-English versions through semi-automated compilation are described. Sections on manual and automatic processing discuss pre- and post-editing, the task program, updater (correction of errors and revision by specialist in a given field), the system employed…

  1. National Data Program for the Marine Environment Technical Development Plan. Final Report, Volume Two.

    ERIC Educational Resources Information Center

    System Development Corp., Santa Monica, CA.

    A national data program for the marine environment is recommended. Volume 2 includes: (1) objectives, scope, and methodology; (2) summary of the technical development plan; (3) agency development plans - Great Lakes and coastal development and (4) marine data network development plans. (Author)

  2. Course of Study Project. Final Report. Vocational-Technical Education Departmental Report, Vol. 17, No. 18.

    ERIC Educational Resources Information Center

    Pennsylvania State Univ., University Park. Div. of Occupational and Vocational Studies.

    Designed for use by area vocational-technical schools and other vocational programs, this project developed courses of study in eight occupational areas: commercial art, appliance repair, automotive mechanics, graphic arts, building trades maintenance, building construction trades, diesel mechanics, and welding. Course-of-study development…

  3. Seminar for Preparation of Professional Personnel for Vocational-Technical Education. Final Report.

    ERIC Educational Resources Information Center

    Dillon, Roy D.; Horner, James T.

    Seminar participants included college administrative officers, state vocational education directors, vocational-technical teacher educators, and Office of Education staff. The purpose of the June, 1968 seminar was to consider strategies for resolving critical vocational education personnel supply and demand problems. Presentations included in the…

  4. 75 FR 33167 - Technical Amendment Language Change From “Wholly” to “Fully”

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... SOCIAL SECURITY ADMINISTRATION 20 CFR Parts 404, 405, 408, 416, and 418 [Docket No. SSA-2009-0062] RIN 0960-AH16 Technical Amendment Language Change From ``Wholly'' to ``Fully'' AGENCY: Social Security... these final rules, call Brian J. Rudick, Office of Regulations, Social Security Administration, 6401...

  5. 76 FR 58144 - Defense Federal Acquisition Regulation Supplement; Presumption of Development Exclusively at...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

    ... technical data package, in cases where the Government may have funded only a small portion of the... subcontractor's asserted restrictions on technical data and computer software. DATES: Effective date: September... data and computer software. More specifically, the final rule affects these validation procedures in...

  6. 75 FR 49408 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Bridges

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    ... Conforming Amendments, Bridges AGENCY: Coast Guard, DHS. ACTION: Final rule. SUMMARY: This rule makes non... technical corrections to Coast Guard bridge and navigable waters regulations. This rule will have no... announces or gathers public opinion or other information regarding bridge matters, nor will it change the...

  7. Research in network management techniques for tactical data communications networks

    NASA Astrophysics Data System (ADS)

    Boorstyn, R.; Kershenbaum, A.; Maglaris, B.; Sarachik, P.

    1982-09-01

    This is the final technical report for work performed on network management techniques for tactical data networks. It includes all technical papers that have been published during the control period. Research areas include Packet Network modelling, adaptive network routing, network design algorithms, network design techniques, and local area networks.

  8. A System for Evaluating Microcomputer Courseware for Vocational and Technical Education. Final Report.

    ERIC Educational Resources Information Center

    Chase, Shirley A.; And Others

    A project was conducted to design a system for evaluating microcomputer courseware for vocational and technical education. Through a literature review and contacts with organizations and individuals involved in courseware evaluation and use, project staff identified and acquired for review documents pertaining to courseware evaulation, vocational…

  9. Bimetallic catalysis for C–C and C–X coupling reactions

    PubMed Central

    Pye, Dominic R.

    2017-01-01

    Bimetallic catalysis represents an alternative paradigm for coupling chemistry that complements the more traditional single-site catalysis approach. In this perspective, recent advances in bimetallic systems for catalytic C–C and C–X coupling reactions are reviewed. Behavior which complements that of established single-site catalysts is highlighted. Two major reaction classes are covered. First, generation of catalytic amounts of organometallic species of e.g. Cu, Au, or Ni capable of transmetallation to a Pd co-catalyst (or other traditional cross-coupling catalyst) has allowed important new C–C coupling technologies to emerge. Second, catalytic transformations involving binuclear bond-breaking and/or bond-forming steps, in some cases involving metal–metal bonds, represent a frontier area for C–C and C–X coupling processes.

  10. The Molecular Design of Active Sites in Nanoporous Materials for Sustainable Catalysis.

    PubMed

    Chapman, Stephanie; Potter, Matthew E; Raja, Robert

    2017-12-02

    At the forefront of global development, the chemical industry is being confronted by a growing demand for products and services, but also the need to provide these in a manner that is sustainable in the long-term. In facing this challenge, the industry is being revolutionised by advances in catalysis that allow chemical transformations to be performed in a more efficient and economical manner. To this end, molecular design, facilitated by detailed theoretical and empirical studies, has played a pivotal role in creating highly-active and selective heterogeneous catalysts. In this review, the industrially-relevant Beckmann rearrangement is presented as an exemplar of how judicious characterisation and ab initio experiments can be used to understand and optimise nanoporous materials for sustainable catalysis.

  11. Computer Aided Enzyme Design and Catalytic Concepts

    PubMed Central

    Frushicheva, Maria P.; Mills, Matthew J. L.; Schopf, Patrick; Singh, Manoj K.; Warshel, Arieh

    2014-01-01

    Gaining a deeper understanding of enzyme catalysis is of great practical and fundamental importance. Over the years it has become clear that despite advances made in experimental mutational studies, a quantitative understanding of enzyme catalysis will not be possible without the use of computer modeling approaches. While we believe that electrostatic preorganization is by far the most important catalytic factor, convincing the wider scientific community of this may require the demonstration of effective rational enzyme design. Here we make the point that the main current advances in enzyme design are basically advances in directed evolution and that computer aided enzyme design must involve approaches that can reproduce catalysis in well-defined test cases. Such an approach is provided by the empirical valence bond method. PMID:24814389

  12. The electron is a catalyst

    NASA Astrophysics Data System (ADS)

    Studer, Armido; Curran, Dennis P.

    2014-09-01

    The electron is an efficient catalyst for conducting various types of radical cascade reaction that proceed by way of radical and radical ion intermediates. But because electrons are omnipresent, catalysis by electrons often passes unnoticed. In this Review, a simple analogy between acid/base catalysis and redox catalysis is presented. Conceptually, the electron is a catalyst in much the same way that a proton is a catalyst. The 'electron is a catalyst' paradigm unifies mechanistically an assortment of synthetic transformations that otherwise have little or no apparent relationship. Diverse radical cascades, including unimolecular radical substitution reactions (SRN1-type chemistry), base-promoted homolytic aromatic substitutions (BHAS), radical Heck-type reactions, radical cross-dehydrogenative couplings (CDC), direct arene trifluoromethylations and radical alkoxycarbonylations, can all be viewed as electron-catalysed reactions.

  13. Water catalysis and anticatalysis in photochemical reactions: observation of a delayed threshold effect in the reaction quantum yield.

    PubMed

    Kramer, Zeb C; Takahashi, Kaito; Skodje, Rex T

    2010-11-03

    The possible catalysis of photochemical reactions by water molecules is considered. Using theoretical simulations, we investigate the HF-elimination reaction of fluoromethanol in small water clusters initiated by the overtone excitation of the hydroxyl group. The reaction occurs in competition with the process of water evaporation that dissipates the excitation and quenches the reaction. Although the transition state barrier is stabilized by over 20 kcal/mol through hydrogen bonding with water, the quantum yield versus energy shows a pronounced delayed threshold that effectively eliminates the catalytic effect. It is concluded that the quantum chemistry calculations of barrier lowering are not sufficient to infer water catalysis in some photochemical reactions, which instead require dynamical modeling.

  14. Recent advances of lanthanum-based perovskite oxides for catalysis

    DOE PAGES

    Zhu, Huiyuan; Zhang, Pengfei; Dai, Sheng

    2015-09-21

    There is a need to reduce the use of noble metal elements especially in the field of catalysis, where noble metals are ubiquitously applied. To this end, perovskite oxides, an important class of mixed oxide, have been attracting increasing attention for decades as potential replacements. Benefiting from the extraordinary tunability of their compositions and structures, perovskite oxides can be rationally tailored and equipped with targeted physical and chemical properties e.g. redox behavior, oxygen mobility, and ion conductivity for enhanced catalysis. Recently, the development of highly efficient perovskite oxide catalysts has been extensively studied. This review article summarizes the recent developmentmore » of lanthanum-based perovskite oxides as advanced catalysts for both energy conversion applications and traditional heterogeneous reactions.« less

  15. Toward a Symphony of Reactivity: Cascades Involving Catalysis and Sigmatropic Rearrangements

    PubMed Central

    Jones, Amanda C.; May, Jeremy A.; Sarpong, Richmond; Stoltz, Brian M.

    2014-01-01

    Catalysis and synthesis are intimately linked in modern organic chemistry. The synthesis of complex molecules is an ever evolving area of science. In many regards, the inherent beauty associated with a synthetic sequence can be linked to a certain combination of the creativity with which a sequence is designed and the overall efficiency with which the ultimate process is performed. In synthesis, as in other endeavors, beauty is very much in the eyes of the beholder.[**] It is with this in mind that we will attempt to review an area of synthesis that has fascinated us and that we find extraordinarily beautiful, namely the combination of catalysis and sigmatropic rearrangements in consecutive and cascade sequences. PMID:24677683

  16. A Continuum of Progress: Applications of N-Hetereocyclic Carbene Catalysis in Total Synthesis

    PubMed Central

    Izquierdo, Javier; Hutson, Gerri E.; Cohen, Daniel T.; Scheidt, Karl A.

    2013-01-01

    N-Heterocyclic carbene (NHC) catalyzed transformations have emerged as powerful tactics for the construction of complex molecules. Since Stetter’s report in 1975 of the total synthesis of cis-jasmon and dihydrojasmon by using carbene catalysis, the use of NHCs in total synthesis has grown rapidly, particularly over the last decade. This renaissance is undoubtedly due to the recent developments in NHC-catalyzed reactions, including new benzoin, Stetter, homoenolate, and aroylation processes. These transformations employ typical as well as Umpolung types of bond disconnections and have served as the key step in several new total syntheses. This Minireview highlights these reports and captures the excitement and emerging synthetic utility of carbene catalysis in total synthesis. PMID:23074146

  17. Heterogeneous Catalysis of Polyoxometalate Based Organic–Inorganic Hybrids

    PubMed Central

    Ren, Yuanhang; Wang, Meiyin; Chen, Xueying; Yue, Bin; He, Heyong

    2015-01-01

    Organic–inorganic hybrid polyoxometalate (POM) compounds are a subset of materials with unique structures and physical/chemical properties. The combination of metal-organic coordination complexes with classical POMs not only provides a powerful way to gain multifarious new compounds but also affords a new method to modify and functionalize POMs. In parallel with the many reports on the synthesis and structure of new hybrid POM compounds, the application of these compounds for heterogeneous catalysis has also attracted considerable attention. The hybrid POM compounds show noteworthy catalytic performance in acid, oxidation, and even in asymmetric catalytic reactions. This review summarizes the design and synthesis of organic–inorganic hybrid POM compounds and particularly highlights their recent progress in heterogeneous catalysis. PMID:28788017

  18. Polymer electrolyte fuel cells for transportation applications

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

    Springer, T.E.; Wilson, M.S.; Garzon, F.H.

    1993-01-01

    The application of the polymer electrolyte fuel cell (PEFC) as a primary power source in electric vehicles has received incrming attention during the last few years. This increased attention has been fueled by a combination of significant technical advances in this field and by the initiation of some projects for the demonstration of a complete, PEFC-based power system in a bus or in a passenger car. Such demonstration pretieds reflect an increased faith of industry in the potential of this technology for transportation applications, or, at least, in the need for a detailed evaluation of this potential Nevertheless, large scalemore » transportation applications of PEFCs requim a continued concerted effort of research on catalysis, materials and components, combined with the engineering efforts addressing the complete power system. This is required to achieve cost effective, highly performing PEFC stack and power system. We describe in this contribution some recent results of work performed within the Core Research PEFC Program at Los Alamos National Laboratory, which has addressed transportation applications of PEFCs.« less

  19. Polymer electrolyte fuel cells for transportation applications

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

    Springer, T.E.; Wilson, M.S.; Garzon, F.H.

    1993-03-01

    The application of the polymer electrolyte fuel cell (PEFC) as a primary power source in electric vehicles has received incrming attention during the last few years. This increased attention has been fueled by a combination of significant technical advances in this field and by the initiation of some projects for the demonstration of a complete, PEFC-based power system in a bus or in a passenger car. Such demonstration pretieds reflect an increased faith of industry in the potential of this technology for transportation applications, or, at least, in the need for a detailed evaluation of this potential Nevertheless, large scalemore » transportation applications of PEFCs requim a continued concerted effort of research on catalysis, materials and components, combined with the engineering efforts addressing the complete power system. This is required to achieve cost effective, highly performing PEFC stack and power system. We describe in this contribution some recent results of work performed within the Core Research PEFC Program at Los Alamos National Laboratory, which has addressed transportation applications of PEFCs.« less

  20. The removal of sulfur dioxide from flue gases

    PubMed Central

    Kettner, Helmut

    1965-01-01

    The growth of industrialization makes it imperative to reduce the amounts of sulfur dioxide emitted into the atmosphere. This article describes various processes for cleaning flue gases, and gives details of new methods being investigated. Wet scrubbing with water, though widely practised, has many disadvantages. Scrubbing with zinc oxide, feasible in zinc works, is more satisfactory. Dry methods use a solid absorbent; they have the advantage of a high emission temperature. Other methods are based on the addition to the fuel or the flue gases of substances such as activated metal oxides, which react with the sulfur to form compounds less harmful than sulfur dioxide. Also being investigated are a two-stage combustion system, in which the sulfur dioxide is removed in the first stage, and the injection of activated powdered dolomite into burning fuel; the resulting sulfates being removed by electrostatic precipitation. A wet catalysis process has recently been developed. Most of the cleaning processes are not yet technically mature, but first results show good efficiency and relatively low cost. PMID:14315714

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