Science.gov

Sample records for finely divided catalysts

  1. Manufacture of finely divided carbon

    SciTech Connect

    Walker, D.G.

    1980-01-22

    Finely divided carbon is manufactured by a process producing a gaseous stream containing carbon monoxide by reacting coal and air in a slagging ash gasifier, separating carbon monoxide from the gaseous mixture, and disproportionating the carbon monoxide to produce finely divided carbon and carbon dioxide, the latter of which is recycled to the gasifier.

  2. The role of the resid solvent in coprocessing with finely divided catalysts. Quarterly report, October--December 1993

    SciTech Connect

    Curtis, C.W.

    1993-12-31

    The reactions with anthracene as a hydrogen acceptor were performed to determine how much hydrogen could be transferred by the hexane soluble resid fraction and hydrogen atmosphere to anthracene. The product distributions obtained by anthracene are given in Table 4. The products obtained from anthracene (ANT) were dihydroanthracene (DHA) and hexahydroanthracene (HHA). When FHC-365 was the resid used in the reaction, very similar amounts of ANT, DHA, and HHA were present after the reaction in both the catalytic and noncatalytic reaction. The predominant product was DHA at 51 to 53 mol%. Slightly more than one-fourth of the ANT remained unreacted. The production of HHA was between 20 and 22%. The amount of H{sub 2} accepted by ANT was the same for both catalytic and noncatalytic reactions. For the reactions with Maya, ANT reacted differently under noncatalytic and catalytic conditions. The reaction products produced were DHA and HHA, with DHA being the predominant product. In the catalytic reaction, substantially more DHA was produced under catalytic conditions and substantially less ANT remained than in the noncatalytic reaction. Under both reaction conditions nearly the same amount of HHA was produced. Under catalytic conditions, nearly twice as much hydrogen was accepted by ANT than under noncatalytic conditions. The product distribution from ANT obtained for the noncatalytic reaction with Maya was similar to dig obtained from ANT when ANT was reacted with FHC-365. The catalyst only seemed to have an effect with Maya resid. The catalyst also had a strong effect on the GC fraction obtained from the reaction using hexane solubles of Maya with ANT. The average boiling point showed a substantial shift toward low boiling constituents.

  3. The role of the resid solvent in co-processing with finely divided catalysts. Quarterly report, January--March 1993

    SciTech Connect

    Curtis, C.W.

    1993-08-01

    The overall objective of this project is to evaluate the role of the resid in coprocessing. The primary purpose of this initial work was to establish under thermal and catalytic reaction conditions whether hydrogen transfer occurred between cycloalkane type structures that are present in resids and aromatics that are present in coal and liquefied coal. The research this quarter focused upon evaluating different reaction systems for performing model donor and model acceptor studies. The first system that was evaluated involved anthracene (ANT) as the model acceptor. Previous results had shown that ANT did not convert substantially in a thermal reaction at 380{degrees}C (Wang 1992); however, more was converted (about 50%) at 440{degrees}C. The results from the reactions performed last quarter indicated that substantial hydrogenation of ANT occurred thermally at 440{degrees}C; more than had been observed previously. The reactors that were used, though, had contained substantial amounts of catalysts prior to the performance of the thermal reactions. Hence, the passivity of the reactors was questioned and new reactors were fabricated. Some of the reactions using ANT were performed again and are reported herein. The second part of the work performed this quarter was to evaluate hydrogen transfer from the cycloalkane, perhydropyrene (PHP), to the aromatic phenanthrene (PHEN). Reactions were performed at a 1:1 PHP to PHEN weight ratio and with a 5:1 PHP to PHEN ratio. The reactions were performed thermally and catalytically at 400 and 425{degrees}C using molybdenum naphthenate and nickel octoate as catalysts. Reactions were also performed with added sulfur either as elemental sulfur or benzothiophene.

  4. The role of the resid solvent in coprocessing with finely divided catalysts. Quarterly report, January--March 1994

    SciTech Connect

    Curtis, C.W.

    1994-07-01

    The research reported in this progress report describes the continuation of coal-resid coprocessing reactions which were begun last quarter (October to December 1993). During, last quarter, Maya and FHC-623 resid were evaluated as whole resids and as the hexane soluble fraction in noncatalytic and catalytic reactions at 400{degree}C. During this current quarter, reactions were performed using Pittsburgh No. 8 bituminous coal and several different solvents including Maya and FHC-623 resids. In order to evaluate the role of the different components in resids, the resids were separated into hexane soluble materials and hexane insoluble materials. The hexane solubles, which should contain the naphthene present in the resid, and the untreated whole resids were reacted with coal at the same liquefaction conditions as when the resids were reacted individually. In the catalytic reactions, a Mo naphthenate precursor was used in the presence of sulfur. The catalyst generated in situ was MoS{sub 2} . The effect of different reaction conditions on the resid was monitored by gas chromatography in which the retention times of the eluting peaks were determined. The amount of eluent present at different retention times was determined and compared. The effect of the reaction system on coal behavior during liquefaction was determined by coal conversion to THF solubles and solvent fractionation of the reaction products.

  5. The role of the resid solvent in coprocessing with finely divided catalysts. Quarterly report, April 1994--June 1994

    SciTech Connect

    Curtis, C.W.

    1994-10-01

    The research reported in this progress report describes the continuation of coal-resid coprocessing reactions which were begun last quarter (January to March 1994). During last quarter, Maya and FHC-623 resid were evaluated as whole resids and as the hexane soluble fraction in noncatalytic and catalytic reactions at 400{degrees}C with Pittsburgh No. 8 coal. During this current quarter, reactions were performed using Blind Canyon bituminous coal and several different solvents including Maya and FHC-623 resids. In order to evaluate the role of the different components in resids, the resids were separated into hexane soluble materials and hexane insoluble materials. The hexane solubles, which should contain the naphthenes present in the resid, and the untreated whole resids were reacted with coal at the same liquefaction conditions as when the resids were reacted individually. In the catalytic reactions, a Mo naphthenate precursor was used in the presence of sulfur. The catalyst generated in situ was MoS{sub 2}. The effect of different reaction conditions on the resid was monitored by gas chromatography in which the retention times of the eluting peaks were determined. The amount of eluent present at different retention times was determined and compared. The effect of the reaction system on coal behavior during liquefaction was determined by coal conversion to THF solubles and solvent fractionation of the reaction products.

  6. Process for recovering fine coal particles from slurry of finely divided coal

    SciTech Connect

    Harada, K.; Ogino, E.; Yoshii, N.

    1982-08-24

    Fine coal particles are recovered from a slurry of finely divided coal by mixing coarsely divided coal and a binder together to cause the binder to adhere to the surfaces of the coarsely divided coal pieces, mixing the slurry with the coal pieces having the binder adhered thereto to cause fine coal particles to adhere to the binder over the surfaces of the coal pieces serving as nuclei and thereby form agglomerates, and separating the agglomerates from the remaining slurry portion to recover the fine coal particles along with the coarsely divided coal and the binder.

  7. Fine particle clay catalysts for coal liquefaction

    SciTech Connect

    Olson, E.S.

    1991-01-01

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing. 5 refs., 1 tab.

  8. Fine particle clay catalysts for coal liquefaction

    SciTech Connect

    Olson, E.S.

    1991-01-01

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and the solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will be performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing.

  9. Fine tuning of activity for nanoscale catalysts.

    SciTech Connect

    Strmcnik, D.; van derVliet, D.; Lucas, C.; Karapetrov, G.; Markovic, N.; Stamenkovic, V.; Materials Science Division

    2008-01-01

    similar levels of catalytic enhancement have been established for corresponding nanoscale materials. In addition to electronic properties we have found how catalytic activity could be affected by the arrangement of surface defects on nanoscale surfaces. Ability to control surface and near surface catalyst properties enables fine tuning of catalytic activity and stability of nanoscale surfaces.

  10. Calcium, Strontium and Barium Homogeneous Catalysts for Fine Chemicals Synthesis.

    PubMed

    Sarazin, Yann; Carpentier, Jean-François

    2016-12-01

    The large alkaline earths (Ae), calcium, strontium and barium, have in the past 15 years yielded a brand new generation of heteroleptic molecular catalysts for the production of fine chemicals. However, the integrity of these complexes is often plagued by ligand redistribution equilibria in solution. This personal account retraces the paths followed in our research group towards the design of stable heteroleptic alkalino-earth complexes, including the use of intramolecular noncovalent Ae···H-Si and Ae···F-C interactions. Their implementation as homogenous precatalysts for reactions such as the intramolecular and intermolecular hydroamination and hydrophosphination of activated alkenes, the hydrophosphonylation of ketones, and the dehydrogenative coupling of amines and hydrosilanes that enable the efficient and controlled formations of CP, CN, or SiN σ-bonds, is presented in a synthetic perspective that highlights their overall outstanding catalytic performance. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    SciTech Connect

    Afanasiev, Pavel

    2014-05-01

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoS{sub x} (x≈4) of 10–30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoS{sub x} under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS{sub 2} materials with very high pore volume and specific surface area, up to 0.45 cm{sup 3}/g and 190 m{sup 2}/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts. - Graphical abstract: Solution reaction in propylene carbonate allows preparing weakly agglomerated molybdenum sulfide with particle size 20 nm and advantageous catalytic properties. - Highlights: • Solution reaction in propylene carbonate yields MoS{sub x} particles near 20 nm size. • Addition of starch as capping agent reduces particles size and hinder agglomeration. • EXAFS at Mo K edge shows rapid oxygen to sulfur exchange in the solution. • Thermal treatment leads to MoS{sub 2} with very high porosity and surface area.

  12. Fine particle clay catalysts for coal liquefaction. Final technical report

    SciTech Connect

    Olson, E.S.

    1995-08-01

    In an effort to develop new disposable catalysts for direct coal liquefaction, several types of clay-supported pyrrhotite catalysts were prepared and tested. These included iron-pillared montmorillonite, mixed iron/alumina-pillared montmorillonite, iron-impregnated montmorillonite, and iron oxometallate-impregnated montmorillonite.

  13. Evaluation of fine-particle catalysts: Activity testing results and phase identification using Mossbauer spectroscopy

    SciTech Connect

    Stohl, F.V.; Diegert, K.V.; Goodnow, D.; Rao, K.R.P.M.; Huggins, F.; Huffman, G.P.

    1994-10-01

    To evaluate and compare the activities/selectivities of fine- particle size catalysts being developed in the DOE/PETC Advanced Research (AR) Coal Liquefaction program by using standard coal liquefaction activity test procedures. Previously reported results have described the standard test procedure that was developed at Sandia to evaluate fine-particle size iron catalysts being developed in DOE/PETC`s AR Coal Liquefaction Program. This test uses DECS-17 Blind Canyon Coal, phenanthrene as the reaction solvent, and a factorial experimental design that enables evaluation of a catalyst over ranges of temperature (350 to 400{degrees}C), time (20 to 60 minutes), and catalyst loading (0 to 1 wt% on a dmmf coal basis). Testing has been performed on Pacific Northwest Laboratories` (PNL) 6-line ferrihydrite catalyst. Results showed that this catalyst is more active than the University of Pittsburgh`s sulfated iron oxide catalyst that was evaluated previously. PNL has also produced two additional batches of catalyst in an effort to optimize their preparation procedures for larger batches. Sandia has observed significant differences in activities among these three catalysts; these differences might be due to particle size effects, the type of drying procedure, or the amount of moisture present. Mossbauer characterization of the iron phases in the coal, catalyst precursors, and tetrahydrofuran (THF) insoluble material from liquefaction reactions has been performed on the University of Pittsburgh`s catalyst and the first PNL catalyst that was tested at Sandia. The Mossbauer results were obtained at the University of Kentucky and will be presented. Future work will include testing additional catalysts being developed in the AR Coal Liquefaction Program, developing procedures to characterize reaction products, and determining the kinetics of the reactions.

  14. Fine particle clay catalysts for coal liquefaction. Quarterly technical report, May 9, 1991--August 8, 1991

    SciTech Connect

    Olson, E.S.

    1991-12-31

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and the solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will be performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing.

  15. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period was devoted to experimental design and fabrication tasks.

  16. Role of the resid solvent in catalytic coprocessing with finely divided catalysts. Final report

    SciTech Connect

    Curtis, C.W.

    1996-01-01

    The role of the resid in coprocessing coal with petroleum resid has been investigated using model systems. The primary question being investigated is whether resid is participating in reactions with coal or if the resid is acting simply as a diluent. Since hydrogen transfer is an important mechanism by which solvent interacts with coal, hydrogen transfer between naphthenes, saturated alicyclic molecules, that represent resid and aromatic molecules that represent coal were examined in reactions with a high pressure H{sub 2} atmosphere that is typical of actual coprocessing. The model naphthene, perhydropyrene, was chosen as the donor species and the models, anthracene, phenanthrene, and benzophenone, were chosen as the acceptor species. Coprocessing reactions of coal with petroleum resid were performed to evaluate the effect of the chemistry of both constituents on coal conversion and the upgrading of the heavy resid. Three heavy resids, Maya, FHC-623 and Manji were used as the whole resid and as fractions that has been separates into hexane solubles and saturate fractions.

  17. The role of the resid solvent in co-processing with finely divided catalysts

    SciTech Connect

    Curtis, C.W.

    1992-01-01

    Goal this quarter was to evaluate the reactivity of an anthracene (H-deficient aromatic) and perhydropyrene (H-rich cycloalkane) system to determine if this system is the one desired for the parametric evaluation. Idea was to determine if hydrogen could be transferred from cycloalkane to aromatic in a hydrogen atmosphere, which is always present in coprocessing. This quarter's work established procedures for performing thermal and catalytic reactions without a solvent, and for analysis of reaction products. Individual thermal and catalytic reactions using anthracene and perhydropyrene were the primary reactions performed this quarter.

  18. Evaluation of fine-particle size catalysts using standard test procedures

    SciTech Connect

    Stohl, F.V.; Diegert, K.V.; Goodnow, D.C.

    1996-07-01

    The goal of this project is to evaluate and compare the activities/selectivities of fine-particle size catalysts being developed in the DOE/PETC Advanced Research (AR) Liquefaction Program by using standard coal liquefaction activity test procedures. Since bituminous and subbituminous coals have significantly different properties, it is feasible that catalysts may perform differently with these coal types. Because all previous testing has been done with the DECS-17 Blind Canyon bituminous coal, it is important to develop the capability of evaluating catalysts using a subbituminous coal. Initial efforts towards developing a subbituminous coal test are aimed at comparing the reactivities of the Wyodak subbituminous coal and the Blind Canyon bituminous coal. Therefore, the same factorial experimental design was used with the Wyodak coal as was used previously with the Blind Canyon coal. In addition, PNL`s 6-line ferrihydrite catalyst precursor was used in the development of the Wyodak coal test procedure because this catalyst is the best powder catalyst found to date in Sandia`s tests with Blind Canyon coal. Results show that Blind Canyon coal yields higher DHP amounts in the reaction products and higher tetrahydrofuran conversions at the higher severity conditions. Wyodak coal gives higher heptane conversions and higher gas yields for all conditions tested.

  19. Polytype and polymorph identification of finely divided aluminous dioctahedral mica individual crystals with SAED. Kinematical and dynamical electron diffraction

    NASA Astrophysics Data System (ADS)

    Gaillot, Anne-Claire; Drits, Victor A.; Veblen, David R.; Lanson, Bruno

    2011-06-01

    This work investigates the potential of selected-area electron diffraction (SAED) for the polytype and polymorph identification of finely divided K-bearing aluminous dioctahedral mica. Individual mica crystals may indeed differ by their layer-stacking sequence and by the inner structure of their octahedral sheets (polytypic and polymorphic variants, respectively). This diversity of natural mica is commonly considered to be responsible for their morphological variety. The present article thus analyzes the intensity distribution between hk0 beams as a function of the crystal structure and thickness. The comparison of ED calculations with experimental diffraction data shows that predicted dynamical effects are not observed for finely divided dioctahedral mica. The influence of different structure defects on calculated intensities is analyzed, and their widespread occurrence in natural mica is hypothesized to be responsible for the limitation of dynamical diffraction effects. SAED may thus be used to identify the structure of individual dioctahedral mica crystals using the kinematical approximation to simulate and qualitatively interpret the observed intensities.

  20. Investigation of fine nanoparticles syngas catalyst (POM) considering their various morphology.

    PubMed

    Fakhroueian, Z; Shafiekhani, A; Yousefi, M; Langroudi, N Afroukhteh; Karami, M; Varmazyar, H; Hemmati, M; Satari, S

    2010-02-01

    Ni/SiO2 fine nanoparticles were prepared by coprecipitation method using various nonionic surfactants as templates with Tylose as a binder dispersant. Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) have been used to study the templates influence on the morphology of the produced samples. Although the phase structure remained as a tetrahedron amorphous cristobalite-sin-SiO2 (101,100), rhombohedron and cubic NiO, but samples with different morphology (homogeneous nano spherical, nano rose flower and nano cubic shapes) have been achieved. These fine nanoparticles as syngas catalysts in Partial Oxidation of Methane to Hydrogen and Carbon Monoxide (POM) have been studied. Because of high Hydrogen production, it is a candidate to be a green fuel. A fixed-bed reactor at P = 1 atm, T = 800 degrees C, H2/CO = 1.8, GHSV (CH4) = 6000/hr and BET = 25, 63.5 and 87.1 m2/gr have been used as POM catalyst. From other hand these fine compounds could be converted to metallic nanotube (nanofiber) at above 850 degrees C and also bamboo shape tip mode carbon nanotube by thermal chemical vapor deposition at 800 degrees C. Transmission Electron Microscopy confirmed the metallic nanotube or single nano crystal growth. The Raman spectroscopy of all samples has been studied to confirm the different formation of Ni-Si. Choosing different templates for production of these nanoparticles could create width range of medical and industrial applications.

  1. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1992-05-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period focused on assembling the supercritical particle generation/collection system. Effort was applied to constructing a shakedown testing plan also.

  2. Finely controlled multimetallic nanocluster catalysts for solvent-free aerobic oxidation of hydrocarbons

    PubMed Central

    Takahashi, Masaki; Koizumi, Hiromu; Chun, Wang-Jae; Kori, Makoto; Imaoka, Takane; Yamamoto, Kimihisa

    2017-01-01

    The catalytic activity of alloy nanoparticles depends on the particle size and composition ratio of different metals. Alloy nanoparticles composed of Pd, Pt, and Au are widely used as catalysts for oxidation reactions. The catalytic activities of Pt and Au nanoparticles in oxidation reactions are known to increase as the particle size decreases and to increase on the metal-metal interface of alloy nanoparticles. Therefore, multimetallic nanoclusters (MNCs) around 1 nm in diameter have potential as catalysts for oxidation reactions. However, there have been few reports describing the preparation of uniform alloy nanoclusters. We report the synthesis of finely controlled MNCs (around 1 nm) using a macromolecular template with coordination sites arranged in a gradient of basicity. We reveal that Cu-Pt-Au MNCs supported on graphitized mesoporous carbon show catalytic activity that is 24 times greater than that of a commercially available Pt catalyst for aerobic oxidation of hydrocarbons. In addition, solvent-free aerobic oxidation of hydrocarbons to ketones at room temperature, using small amounts of a radical initiator, was achieved as a heterogeneous catalytic reaction for the first time. PMID:28782020

  3. METHOD OF PURIFYING CATALYSTS

    DOEpatents

    Joris, G.G.

    1958-09-01

    It has been fuund that the presence of chlorine as an impurity adversely affects the performance of finely divided platinum catalysts such as are used in the isotopic exchange process for the production of beavy water. This chlorine impurity may be removed from these catalysts by treating the catalyst at an elevated temperature with dry hydrogen and then with wet hydrogen, having a hydrogen-water vapor volume of about 8: 1. This alternate treatment by dry hydrogen and wet hydrogen is continued until the chlorine is largely removed from the catalyst.

  4. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-09-01

    The program objective is to generate ultra-fine catalyst particles (20 to 400 {Angstrom} in size) and quantify their potential for improving coal dissolution in the solubilization stage of two-stage catalytic-catalytic liquefaction systems. In the first quarterly report for this program the concept behind our approach was detailed, the structure of the program was presented, key technical issues were identified, preliminary designs were outlined, and technical progress was discussed. All progress made during the second quarter of this program related to experiment design of the proposed supercritical expansion technique for generating ultra-fine, iron compound, catalyst particles. This second quarterly report, therefore, presents descriptions of the final designs for most system components; diagnostic approaches and designs for determining particles size and size distributions, and the composition of the pre-expansion supercritical solution; and the overall technique progress made during this reporting period. 6 refs., 15 figs., 1 tab.

  5. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

    SciTech Connect

    Klein, M.T.

    1991-12-30

    The purpose of this work is to investigate the kinetics-assisted design, synthesis and characterization of fme-pardcle, unsupported catalysts for coal liquefaction. The goal is to develop a fundamental understanding of coal catalysis and catalysts that will, in turn, allow for the specification of a novel optimal catalyst for coal liquefaction.

  6. The role of the resid solvent in coprocessing with finely divided catalysts. Quarterly report, July--September 1993

    SciTech Connect

    Curtis, C.W.

    1993-12-31

    The research performed this quarter involved evaluating the resid as the solvent in coprocessing. Since the objective of this research contract is to determine if the naphthenic portion of resids is able to transfer hydrogen to coal, the resid was fractionated in order to obtain different compositional fractions for liquefaction reactions. In order to evaluate different fractions of resids, the fractions must first be separated by liquid chromatography. The literature was surveyed as described below to determine the most feasible of effecting the separation. Methods used to analyze the fractions were also examined. On the basis of the information obtained, an experimental procedure was developed for separating the resid into fractions and then analyzing the fractions by Fourier transform infrared spectroscopy (FTIR) and by {sup 13}C nuclear magnetic resonance.

  7. Role of the resid solvent in catalytic coprocessing with finely divided catalysts. Quarterly report, April 1995--June 1995

    SciTech Connect

    1996-01-01

    The research reported in this progress report describes the continuation of coal-resid coprocessing reactions that were discussed in the January to March 1995 Quarterly Report. During previous quarters, Maya and FHC-623 resids were evaluated in non-catalytic and catalytic reactions at 400{degrees}C with Pittsburgh No. 8 and DECS-17 Blind Canyon coals. From the complete reaction matrix containing the two coals and two resids, it was found that the influence of resids on coprocessing depended on the type of coal used; for example, under catalytic reaction conditions, the hexane solubles of Maya resid increased coal conversion of Pittsburgh No. 8 coal but decreased that of DECS-17. In order to observe the intrinsic behavior of resids during coprocessing, another resid, Manjii, and another coal, Illinois No. 6, are being tested. These reactions were begun this quarter. The results are reported herein. In order to evaluate the role of the different components in resids, the resids were separated into hexane soluble materials and hexane insoluble materials. The hexane solubles, which should contain the naphthenes present in the resid, and the untreated whole resids were reacted with coal at equivalent liquefaction conditions and at the same conditions as when the resids were reacted individually.

  8. Role of the resid solvent in catalytic coprocessing with finely divided catalysts. Quarterly report, January--March 1995

    SciTech Connect

    Curtis, C.W.

    1995-07-01

    The research reported in this progress report describes the continuation of coal-resid coprocessing reactions that were discussed in the July to September 1994 Quarterly Report. During previous quarters, Maya and FHC-623 resids were evaluated in noncatalytic and catalytic reactions at 400{degrees}C with Pittsburgh No. 8 and DECS-17 Blind Canyon coals. From the complete reaction matrix containing the two coals and two resids, it was found that the influence of resids on coprocessing depended on the type of coal used; for example, under catalytic reaction conditions, the hexane solubles of Maya resid increased coal conversion of Pittsburgh No. 8 coal but decreased that of DECS-17. In order to observe the intrinsic behavior of resids during coprocessing, another resid, Manji, and another coal, Illinois No. 6, are being tested. These reactions were begun this quarter. The results obtained are reported in this report.

  9. The role of the resid solvent in co-processing with finely divided catalysts. Quarterly report April--June 1993

    SciTech Connect

    Curtis, C.W.

    1993-11-01

    The primary purpose of the work performed this quarter was to establish under thermal and catalytic reaction conditions whether hydrogen transfer occurred between cycloalkane type structures that are present in resids and heteroatomic species that are present in coal and liquefied coal. The research this quarter focused upon evaluating benzophenone (BENZ) as a model acceptor for hydrogen that might be transferred from a cycloalkane, perhydropyrene (PHP), under coprocessing conditions. Hence, a number of reactions was performed in which BENZ was reacted alone in hydrogen and nitrogen atmospheres in the presence and absence of a catalytic agent, molybdenum naphthenate. Reactions were also performed using a combination of PHP and BENZ at a 1 to 1 weight ratio. Also performing this quarter were initial separations with petroleum resids. Two different resids were used, Maya and LHC-362. The literature was also surveyed to determine important characteristics that should be evaluated for selecting resids. The resids that are desired for this project are resids with high-, medium-, and low-naphthenic content. Different levels of asphaltenes are also desirable. Resids with these characteristics are currently being sought. The model compound PHP that had been commercially available as naphthene representative of resids is now no longer available. Hence, several scoping experiments were performed in order to determine conditions for synthesizing PHP. The synthesis procedure reported in US Patent 3,303,227 was used as a basis for this work. Although more than 85% PHP was synthesized, partially hydrogenated pyrenes were also produced which will require separation in order to obtain pure PHP.

  10. The role of the resid solvent in co-processing with finely divided catalysts. Quarterly report, October--December 1992

    SciTech Connect

    Curtis, C.W.

    1992-12-31

    Goal this quarter was to evaluate the reactivity of an anthracene (H-deficient aromatic) and perhydropyrene (H-rich cycloalkane) system to determine if this system is the one desired for the parametric evaluation. Idea was to determine if hydrogen could be transferred from cycloalkane to aromatic in a hydrogen atmosphere, which is always present in coprocessing. This quarter`s work established procedures for performing thermal and catalytic reactions without a solvent, and for analysis of reaction products. Individual thermal and catalytic reactions using anthracene and perhydropyrene were the primary reactions performed this quarter.

  11. A facile method for nickel catalyst immobilization on ultra fine Al{sub 2}O{sub 3} powders

    SciTech Connect

    Zhang, T.; Wen, G.; Huang, X.X.; Zhong, B.; Zhang, X.D.; Bai, H.W.; Yu, H.M.

    2010-07-15

    A pure nickel coating has been successfully plated on the surface of ultra fine Al{sub 2}O{sub 3} particles via a facile electroless plating method. Coating morphology and crystallite size can be tailored by pH values. Dense coating with the maximum crystallite size of 24 nm was obtained at pH 11.0 and porous coating with the minimum crystallite size of 15 nm was obtained at pH value 12.5. The plated powders have been demonstrated to be an effective catalyst for growing boron nitride nanotubes.

  12. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

    SciTech Connect

    Klein, M.T.

    1991-09-11

    A series of carbonyl-based homogeneous catalyst precursors has been prepared. These species include: Fe(CO){sub 4}PPh{sub 3}, Fe(CO){sub 3}(PPh{sub 3}){sub 2}, Fe(CO){sub 2}(PPh{sub 3}){sub 2}CS{sub 2}, S{sub 2}Fe{sub 2}(CO){sub 6}, S{sub 2}Fe{sub 3}(CO){sub 9}. Fe(CO){sub 4}PPh{sub 3} was prepared by a combined photochemical and thermal route from triphenylphosphine (PPh{sub 3}) in iron pentacarbonyl (Fe(CO){sub 5}). This preparation procedure, which is selective to the monosubstituted product, is outlined herein. Currently these compounds are being tested as catalysts/catalyst precursors with coal or model compounds in the tubing bomb reactors to provide information relating catalytic activity to catalyst structure and properties. (VC)

  13. Uranium resources in fine-grained carbonaceous rocks of the Great Divide Basin, south-central Wyoming. National Uranium Resource Evaluation

    SciTech Connect

    Burger, J.A.; Roe, L.M. II; Hacke, C.M.; Mosher, M.M.

    1982-11-01

    The uranium resources of the fine-grained carbonaceous rocks of the Great Divide Basin in southern Wyoming were assessed. The assessment was based primarily on data from some 600 boreholes. The data included information from geophysical logs, lithologic logs and cores, and drill cuttings. The cores and cuttings were analyzed for chemical U/sub 3/O/sub 8/, radiometric U, Th and trace elements. Selected samples were examined by thin section, sieve analysis, x-ray, SEM, ion probe, and alpha track methods. The uranium is associated with fine-grained carbonaceous shales, siltstones, mudstones, and coals in radioactive zones 5 to 50 ft thick that are continuous over broad areas. These rocks have a limited stratigraphic range between the Red Desert tongue of the Wasatch Formation and the lower part of the Tipton tongue of the Green River Formation. Most of this uranium is syngenetic in origin, in part from the chelation of the uranium by organic material in lake-side swamps and in part as uranium in very fine detrital heavy minerals. The uraniferous fine-grained carbonaceous rocks that exceed a cutoff grade of 100 ppM eU/sub 3/O/sub 8/ extend over an area of 542 mi/sup 2/ and locally to a depth of approximately 2000 ft. The uraniferous area is roughly ellipical and embraces the zone of change between the piedmont and alluvial-fan facies and the lacustrine facies of the intertonguing Battle Spring, Wasatch, and Green River Formations. About 1.05 x 10/sup 6/ tons U/sub 3/O/sub 8/, based on gross-gamma logs not corrected for thorium, are assigned to the area in the first 500 ft; an estimated 3.49 x 10/sup 6/ tons are assigned to a depth of 1000 ft. These units also contain a substantial thorium resource that is also associated with fine-grained rocks. The thorium-to-uranium ratio generally ranges between 1 and 4. A thorium resource of 3.43 x 10/sup 6/ tons to a depth of 500 ft is estimated for the assessment area. 5 figures, 3 tables.

  14. Sources of fine organic aerosol. 2. Noncatalyst and catalyst-equipped automobiles and heavy-duty diesel trucks

    SciTech Connect

    Rogge, W.F.; Hildemann, L.M.; Mazurek, M.A.; Cass, G.R. ); Simoneit, B.R.T. )

    1993-04-01

    Gasoline- and diesel-powered vehicles are known to contribute appreciable amounts of inhalable fine particulate matter to the atmosphere in urban areas. Internal combustion engines burning gasoline and diesel fuel contribute more than 21% of the primary fine particulate organic carbon emitted to the Los Angeles atmosphere. In the present study, particulate (d[sub p] [le] 2 [mu]m) exhaust emissions from six noncatalyst automobiles, seven catalyst-equipped automobiles, and two heavy-duty diesel trucks are examined by gas chromatography/mass spectrometry. The purposes of this study are as follows: (a) to search for conservative marker compounds suitable for tracing the presence of vehicular particulate exhaust emissions in the urban atmosphere, (b) to compile quantitative source profiles, and (c) to study the contributions of fine organic particulate vehicular exhaust to the Los Angeles atmosphere. More than 100 organic compounds are quantified, including n-alkanes, n-alkanoic acids, benzoic acids, benzaldehydes, PAH, oxy-PAH, steranes, pentacyclic triterpanes, azanaphthalenes, and others. Although fossil fuel markers such as steranes and pentacyclic triterpanes can be emitted from other sources, it can be shown that their ambient concentrations measured in the Los Angeles atmosphere are attributable mainly to vehicular exhaust emissions. 102 refs., 9 figs., 6 tabs.

  15. Fine-Tuning the Activity of Metal-Organic Framework-Supported Cobalt Catalysts for the Oxidative Dehydrogenation of Propane.

    PubMed

    Li, Zhanyong; Peters, Aaron W; Platero-Prats, Ana E; Liu, Jian; Kung, Chung-Wei; Noh, Hyunho; DeStefano, Matthew R; Schweitzer, Neil M; Chapman, Karena W; Hupp, Joseph T; Farha, Omar K

    2017-10-04

    Few-atom cobalt-oxide clusters, when dispersed on a Zr-based metal-organic framework (MOF) NU-1000, have been shown to be active for the oxidative dehydrogenation (ODH) of propane at low temperatures (< 230 °C), affording a selective and stable propene production catalyst. In our current work, a series of promoter ions with varying Lewis acidity, including Ni(II), Zn(II), Al(III), Ti(IV) and Mo(VI), are anchored as metal-oxide,hydroxide clusters to NU-1000 followed by Co(II) ion deposition, yielding a series of NU-1000-supported bimetallic-oxo,hydroxo,aqua clusters. Using difference envelope density (DED) analyses, the spatial locations of the promoter ions and catalytic cobalt ions are determined. For all samples the promoter ions are sited between pairs of Zr6 nodes along the MOF c axis whereas the location of the cobalt ions varies with the promoter ions. These NU-1000-supported bimetallic-oxide clusters are active for propane ODH after thermal activation under O2 to open a cobalt coordination site and to oxidize Co(II) to Co(III), as evidenced by operando X-ray absorption spectroscopy at the Co K-edge. In accord with the decreasing Lewis acidity of the promoter ion, catalytic activity increases in the order: Mo(VI)fine-tune the structure-dependent activity of MOF-supported heterogeneous catalysts. Coupled with mechanistic studies-computational or experimental-this ability may translate into informed prediction of improved catalysts for propane ODH and other chemical reactions.

  16. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

    SciTech Connect

    Klein, M.T.

    1991-02-22

    The first task in our proposed study of catalysts for coal liquefaction was to prepare ultrafine dispersed metal sulfide particles by reactive precipitation from solutions of appropriate metal precursors. At this point, equipment to allow us to prepare these air-sensitive materials in an anaerobic environment has been acquired and assembled. Initial experiments aimed at synthesizing iron sulfide particles have been initiated. As part of the investigation of short contact time catalytic coal liquefaction, initial efforts focused on the noncatalytic pyrolysis reactions of coal and a model compound, Dibenzyl ether (DBE). Two different reactor configurations were examined; catalytic experiments are planned for the coming month.

  17. Pd-Pt Catalysts on Fluorinated Alumina Support Studied by X-Ray Absorption Fine Structure

    NASA Astrophysics Data System (ADS)

    Yan, Wensheng; Li, Zhongrui; Wei, Zheng; Wei, Shiqiang

    2007-02-01

    A series of bi-metallic Pd-Pt catalysts supported on both pristine and fluorinated alumina supports were investigated with x-ray absorption spectroscopy. It was found that Pd and Pt form small alloy particles on the pristine alumina support; the composition and the cluster size of the PdPt bimetallic alloys, and the electronic properties of the metals were significantly altered on the fluorinated support. The remarkable increase in sulfur tolerance of the PdPt metallic clusters supported on the fluorine pretreated alumina can be attributed to an electronic depletion of the metals, large particle size and direct participation of the acid sites in the reaction.

  18. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, April 1, 1991--June 30, 1991

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period was devoted to experimental design and fabrication tasks.

  19. Microwave-assisted extraction of rare earth elements from petroleum refining catalysts and ambient fine aerosols prior to inductively coupled plasma-mass spectrometry.

    PubMed

    Kulkarni, Pranav; Chellam, Shankararaman; Mittlefehldt, David W

    2007-01-09

    A robust microwave-assisted acid digestion procedure followed by inductively coupled plasma-mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM(2.5)). High temperature (200 degrees C), high pressure (200 psig), acid digestion (HNO(3), HF and H(3)BO(3)) with 20 min dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst and PM(2.5). This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using (115)In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu and Dy in ambient PM(2.5) in an industrial area of Houston, TX.

  20. Microwave-assisted Extraction of Rare Earth Elements from Petroleum Refining Catalysts and Ambient Fine Aerosols Prior to Inductively Coupled Plasma - Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Kulkarni, Pranav; Chellam, Shankar

    2006-01-01

    In the absence of a certified reference material, a robust microwave-assisted acid digestion procedure followed by inductively coupled plasma - mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM2.5). High temperature (200 C), high pressure (200 psig), acid digestion (HNO3, HF, and H3BO3) with 20 minute dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst, and PM2.5. This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb, and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy, and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using 115In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu, and Dy in ambient PM2.5 in an industrial area of Houston, TX.

  1. Efficacy of a half-grip technique using a fine tip LigaSure™, Dolphin Tip Sealer/Divider, on liver dissection in swine model.

    PubMed

    Toyama, Yoichi; Yoshida, Seiya; Saito, Ryota; Iwase, Ryota; Haruki, Koichiro; Okui, Norimitsu; Shimada, Jun-ichi; Kitamura, Hiroaki; Matsumoto, Michinori; Yanaga, Katsuhiko

    2015-08-20

    Recently, a lot of energy devices in the surgical field, especially in the liver surgery, have been developed, and a fine tip LigaSure™, Dolphin Tip Sealer/Divider (DT-SD) also has been used frequently to dissect liver parenchyma as well as ultrasonically activated device (USAD). However, the utility of this instrument for liver dissection (LD) is still unknown. Moreover, to reduce bleeding during LD, a half-grip technique (HGT) was contrived. We herein report an experimental study in swine model to evaluate the feasibility and effectiveness of HGT using DT-SD for LD. The swine model experiment was carried out under general anesthesia by veterinarians. LD was performed repeatedly by DT-SD with the HGT (Group A, n = 6), or the conventional clamp-crush technique (CCT) (Group B, n = 6), and by variable mode USAD (Group C, n = 6). The dissection length and depth (cm) as well as bleeding volume (g) were measured carefully, and the dissection area (cm(2)) and speed (cm(2)/min) were calculated precisely. Histological examinations of the dissection surfaces were also executed. Mann-Whitney's U test was used for Statistical analyses with variance at a significance level of 0.05. Among the three groups, the three averages of dissection lengths were unexpectedly equalized to 8.3 cm. The dissection area (cm(2)) was 9.9 ± 5.1 in Group A, 9.8 ± 4.7 in Group B, and 9.9 ± 4.5 in Group C. The mean blood loss during LD was 10.6 ± 14.8 g in Group A, 41.4 ± 39.2 g in Group B, and 34.3 ± 39.2 g in Group C. For Group A, the bleeding rate was the least, 0.9 ± 1.0 g/cm(2), and the average depth of coagulation was the thickest, 1.47 ± 0.29 mm, among the three groups (p < 0.05). The dissection speed in Group A (1.3 ± 0.3 cm(2)/min) was slower, than that in Group C (p < 0.05). This report indicates firstly that the HGT using DT-SD bring the least blood loss when compared with CCT or USAD. Although the HGT is feasible and useful for LD, to popularize the HGT, further clinical

  2. Evident Improvement of Electrochemical Water Oxidation by Fine Tuning the Structure of Tetradentate N4 Ligands of Molecular Copper Catalysts.

    PubMed

    Shen, Junyu; Wang, Mei; Gao, Jinsuo; Han, Hongxian; Liu, Hong; Sun, Licheng

    2017-09-03

    Two copper complexes, [L1Cu(OH2)](BF4)2 [1, L1 = N,N'-dimethyl-N,N'-bis(pyridin-2-ylmethyl)-1,2-diaminoethane] and [L2Cu(OH2)](BF4)2 [2, L2 = 2,7-bis(2-pyridyl)-3,6-diaza-2,6-octadiene], were prepared as molecular water oxidation catalysts. Complex 1 displayed an overpotential (η) of 1.07 V at 1 mA cm-2 and an observed rate constant (kobs) of 13.5 s-1 at η 1.0 V in pH 9.0 phosphate buffer solution, while 2 exhibited a significantly smaller η (0.70 V) to reach 1 mA cm-2 and a higher kobs (50.4 s-1) than 1 under identical test conditions. Additionally, 2 displayed a better stability than 1 in controlled potential electrolysis experiments in a Faradaic efficiency of 94% for O2 evolution at 1.58 V, when a casing tube was used for Pt cathode. The possible mechanism for 1- and 2-catalyzed O2 evolution reactions is discussed based on the experimental evidence. These comparative results indicate that fine tuning structures of tetradentate N4 ligands can bring about significant change in the performance of copper complexes for electrochemical water oxidation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, February 9, 1992--May 8, 1992

    SciTech Connect

    Olson, E.S.

    1995-10-01

    An investigation of new methods for the production of iron-pillared clay catalysts and clay-supported iron hydroxyoxide catalysts and the determination of their catalytic activities was continued in this quarter. Previous work in this project showed that a catalyst prepared by adding ferric nitrate and ammonia to an acid-washed clay gave an active catalyst following sulfidation. Further testing of this catalyst with a model compound showed that its hydrocracking activity was considerably lower when used in 10% concentration rather than 50%. In contrast, the mixed iron/alumina pillared clay catalysts were still highly effective at 10% concentration and gave good conversions at one and two hour reaction times. An investigation of preparation methods demonstrated that calcination of both the iron hydroxyoxide-impregnated clay and the mixed iron/alumina pillared clays is essential for activity. High activity was obtained for these catalysts only when they were removed from the aqueous media rapidly, dried, and calcined. The use of ferric sulfate to prepare a clay-supported sulfated iron catalyst was attempted, the resulting catalyst was relatively inactive for hydrocracking. Several new catalysts were synthesized with the idea of decreasing the pillar density and thereby increasing the micropore volume. A zirconia-pillared clay with low pillar density was prepared and intercalated with triiron complex. The hydrocracking activity of this catalyst was somewhat lower than that of the mixed alumina/iron-pillared catalyst. Other new catalysts, that were prepared by first pillaring with an organic ammonium pillaring agent, then introducing a lower number of silica or alumina pillars, and finally the iron component, were also tested. The mixed alumina/iron-pillared catalysts was further tested at low concentration for pyrene hydrogenating and hydrocracking activities.

  4. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, May 9, 1992--August 8, 1992

    SciTech Connect

    Olson, E.S.

    1995-10-01

    An investigation of new methods for the production of mixed pillared clay catalysts and clay-supported catalysts and determination of their catalytic activities were continued in this quarter. To demonstrate the reproducibility of the preparative method for high activity iron/alumina-pillared montmorillonite catalysts, a new batch of the catalyst was prepared and tested for hydrocracking activity with bibenzyl. This preparation gave conversion and product distribution similar to that reported previously. The mixed iron/alumina-pillared clay was also prepared using a pillaring solution that was aged for longer period of time. To determine the importance of the type of pillaring support in hydrocracking activity, iron/zirconia-pillared montmorillonite was prepared using the same technique as that for iron/alumina-pillared montmorillonite. The reaction of bibenzyl with the sulfided iron/zirconia-pillared catalyst gave a lower hydrocracking conversion than the iron/alumina-pillared catalyst. Addition of a second catalytic metal to the clay support was attempted to determine if a synergistic effect could improve liquefaction. Ferric nitrate and stannous chloride were added to the clay, but the resulting catalyst was relatively poor for hydrocracking and hydrogenation compared with ferric nitrate supported on the clay. New disposable iron catalysts with high acidity and surface area are desired for coal liquefaction. Synthetic iron aluminosilicates were prepared by methods similar to those used for the nickel-substituted synthetic mica montmorillonite (NiSMM) catalysts, which are very effective for hydrogenation and reforming of hydrocarbons. The iron aluminosilicate catalysts were tested for hydrocracking and hydrogenation of bibenzyl, naphthalene and pyrene. Pyrene hydrogenation was effectively catalyzed by the sulfided synthetic iron catalyst.

  5. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, January 1, 1992--March 31, 1992

    SciTech Connect

    Not Available

    1992-05-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period focused on assembling the supercritical particle generation/collection system. Effort was applied to constructing a shakedown testing plan also.

  6. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, May 8, 1993--August 8, 1993

    SciTech Connect

    Olson, E.S.

    1995-10-01

    High hydrocracking and liquefaction activity can be achieved with 10 wt.% of sulfided clay-supported iron catalysts. Further tests and demonstrations of this activity were required. Iron hydroxyoxide was generated on acid-treated montmorillonite. The new batch of catalyst exhibited high hydrocracking activity, Three hour tests with the solubilized intermediate from low-severity treatment of Wyodak coal (LSW) gave a high conversion (45%) of the heptane-insoluble LSW intermediate to heptane-soluble products. An investigation of new methods for the production of catalysts from tetralin-soluble iron oxometallates and the determination of their catalytic activities was continued in this quarter. Iron oxotitanate and iron oxoaluminate gave very high conversions of LSW to heptane solubles (61% and 54%, respectively). The high yields of heptane soluble products obtained with these catalysts offers a potential for use in liquefaction stages with solubilized coal, or at least serve as a model for producing active catalysts via mixed metal oxides. Methods for successfully testing dispersed iron catalysts with the low-severity intermediate were also devised. Catalyst recovered from the dispersed iron hydroxyoxide-catalyzed reaction of ion-exchanged Wyodak gave a high conversion (47%) of LSW to heptane solubles.

  7. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, November 9, 1991--February 8, 1992

    SciTech Connect

    Olson, E.S.

    1995-10-01

    The investigation of methods for the production and testing of iron-pillared clay catalysts was continued in this quarter. The surface area of the mixed alumina/iron pillared clay catalyst decreased to 51 m{sup 2}/g on sulfidation. Thus the stability of the alumina pillars during the sulfidation and thermal treatments prevented the total collapse that occurred in the case of the iron-pillared clays. Previously the mixed alumina/iron pillared clays were tested for hydrocracking activities with bibenzyl. This testing was extended to a determination of activity with a second model compound substrate (pyrene), representative of the polynuclear aromatic systems present in coal. Testing of the mixed alumina/iron-pillared catalysts with 1-methylnaphthalene gave interesting results that demonstrate shape selectivity. The clay-supported iron hydroxyoxide catalysts prepared by impregnation of iron species on acidic clays were further investigated. Sulfidation of these catalysts using the carbon disulfide in situ method gave hydrocracking activities with bibenzyl that were somewhat less than those obtained by presulfidation with H{sub 2}/H{sub 2}S mixtures. Liquefaction of Wyodak subbituminous coal was very successful with the iron impregnated clay catalyst, giving a highly soluble product. High conversions were also obtained with the mixed alumina/iron-pillared clay catalyst, but the yield of oil-solubles was considerably lower. Several new catalysts were synthesized with the idea of decreasing the pillar density and thereby increasing the micropore volume. These catalysts were prepared by first pillaring with an organic ammonium pillaring agent, then introducing a lower number of silica or alumina pillars. Finally the iron component was added either before or after thermal removal of organic pillars.

  8. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, November 9, 1992--February 8, 1993

    SciTech Connect

    Olson, E.S.

    1995-10-01

    The mixed iron/alumina pillared clay catalysts and clay-supported iron catalysts have been shown in previous reports of this project to significantly improve yields of heptane-soluble products obtained in the liquefaction of both as received and acid-exchanged Wyodak subbituminous coal and Blind Canyon bituminous coal. In this quarter, the soluble product (LSW) obtained from the noncatalytic low-severity liquefaction of Wyodak coal was used as a feed to determine the activity of iron based catalysts for the hydrogenation and depolymerization steps. Comparison data for liquefaction of the soluble LSW with other catalysts were desired, and these data were obtained for a dispersed form of iron sulfide, prepared via iron hydroxyoxide (PETC method). The iron oxyhydroxide catalyst was directly precipitated on LSW product using either water or ethanol as the solvent. An insight into the functioning of the mixed iron/alumina pillared clay in coal liquefaction was investigated by preparing and studying an iron oxoaluminate structure. An investigation of new methods for the production of tetralin soluble iron oxometallate catalysts and the determination of their catalytic activities was continued in this quarter. The hydrogenation activity of iron oxoaluminate was investigated using pyrene and 1-methylnaphthalene as the test compounds, and results were compared with thermal reactions. In order to determine the loss of activity, recovered catalyst was recycled a second time for the hydrotreating of pyrene. Reaction of 1-methylnaphthalene with iron oxoaluminate also gave very high conversion to 1- and 5-methyltetralins and small amount of 2- and 6-methyltetralins. Liquefaction of Wyodak subbituminous and Blind Canyon bituminous coal was investigated using an in situ sulfided soluble iron oxoaluminate catalyst.

  9. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, February 9, 1993--May 8, 1993

    SciTech Connect

    Olson, E.S.

    1995-10-01

    An investigation of new methods for the production and utilization of tetralin-soluble iron oxometallate precursors for coal liquefaction catalysts was continued in this quarter. Further descriptions of the catalytic activities of the sulfided forms were obtained. The hydrogenation activities of catalysts derived from iron oxotitanate and cobalt oxoaluminate were investigated using pyrene as a the test compound, and results were compared with thermal reactions. The hydrogenation activity of iron oxotitanate was superior to other catalysts including iron oxoaluminate. The hydrogenation activity of cobalt oxoaluminate was similar to that of iron oxoaluminate reported in previous quarterly report. The liquefaction of Wyodak subbituminous coal was investigated using in situ sulfided iron oxotitanate catalyst. In order to improve the usefulness of iron oxoaluminate as a liquefaction catalyst, iron oxoaluminate was supported on acid-treated montmorillonite (K-10). Supporting the iron oxoaluminate on an acidic support significantly improved the hydrogenation activity of iron oxoaluminate. The hydrocracking activity was increased by a large factor. Thus the aluminate and titanate structures surrounding the pyrrhotite that forms during sulfidation have a beneficial effect in preventing deactivation of the iron sites, and the presence of the acidic sites in the clay results in effective catalytic synergism between catalyst and support. These clay-supported iron oxometallates are highly promising catalysts for coal liquefaction. Iron oxyhydroxide and triiron supported on acid-treated montmorillonite (K-10) were tested for the liquefaction of ion-exchanged Wyodak (IEW) to minimize effects of the coal mineral matter. Both sulfided catalysts gave very high conversions of coal to THF-soluble and heptane-soluble (oils) products.

  10. PRELIMINARY IN-SITU X-RAY ABSORPTION FINE STRUCTURE EXAMINATION OF PT/C AND PTCO/C CATHODE CATALYSTS IN AN OPERATIONAL POLYMER ELECTROLYTE FUEL CELL

    SciTech Connect

    Phelan, B.T.; Myers, D.J.; Smith, M.C.

    2009-01-01

    State-of-the-art polymer electrolyte fuel cells require a conditioning period to reach optimized cell performance. There is insuffi cient understanding about the behavior of catalysts during this period, especially with regard to the changing environment of the cathode electrocatalyst, which is typically Pt nanoparticles supported on high surface area Vulcan XC-72 carbon (Pt/C). The purpose of this research was to record preliminary observations of the changing environment during the conditioning phase using X-Ray Absorption Fine Structure (XAFS) spectroscopy. XAFS was recorded for a Pt/C cathode at the Pt L3-edge and a PtCo/C cathode at both the Pt L3-edge and Co K-edge. Using precision machined graphite cell-blocks, both transmission and fl uorescence data were recorded at Sector 12-BM-B of Argonne National Laboratory’s Advanced Photon Source. The fl uorescence and transmission edge steps allow for a working description of the changing electrocatalyst environment, especially water concentration, at the anode and cathode as functions of operating parameters. These features are discussed in the context of how future analysis may correlate with potential, current and changing apparent thickness of the membrane electrode assembly through loss of catalyst materials (anode, cathode, carbon support). Such direct knowledge of the effect of the conditioning protocol on the electrocatalyst may lead to better catalyst design. In turn, this may lead to minimizing, or even eliminating, the conditioning period.

  11. Catalyst suppliers consolidate further, offer more catalysts

    SciTech Connect

    Rhodes, A.K.

    1995-10-02

    The list of suppliers of catalysts to the petroleum refining industry has decreased by five since Oil and Gas Journal`s survey of refining catalysts and catalytic additives was last published. Despite the consolidation, the list of catalyst designations has grown to about 950 in this latest survey, compared to 820 listed in 1993. The table divides the catalysts by use and gives data on their primary differentiating characteristics, feedstock, products, form, bulk density,catalyst support, active agents, availability, and manufactures.

  12. Applications of extended X-ray absorption fine-structure spectroscopy to studies of bimetallic nanoparticle catalysts.

    PubMed

    Frenkel, Anatoly I

    2012-12-21

    Extended X-ray absorption fine structure (EXAFS) spectroscopy has been used to study short range order in heterometallic alloys for almost four decades. In this critical review, experimental, theoretical and data analytical approaches are revisited to examine their power, and limitations, in studies of bimetallic nanocatalysts. This article covers the basics of EXAFS experiments, data analysis, and modelling of nanoscale clusters. It demonstrates that, in the best case scenario, quantitative information about the nanocatalyst's size, shape, details of core-shell architecture, as well as static and dynamic disorder in metal-metal bond lengths can be obtained. The article also emphasizes the main challenge accompanying such insights: the need to account for the statistical nature of the EXAFS technique, and discusses corrective strategies.

  13. Coprocessing of 4-(1-napthylmethyl)bibenzyl with waste tires using finely dispersed iron and molybdenum catalysts

    SciTech Connect

    Tang, Y.; Curtis, C.W.

    1994-12-31

    Coliquefaction of waste tires with coal is a feasible method for upgrading both materials. To evaluate the effect of waste tires on reactions that occur during liquefaction, waste tire and carbon black, a component of tires, were reacted in the presence of 4-(1-naphthylmethyl)bibenzyl (NMBB), a model coal compound known to hydrocrack at liquefaction conditions. Waste tires promoted NMBB hydrocracking compared to no additive although carbon black, introduced at the level present in waste tires increased hydrocracking more. Combining Mo naphthenate with waste tire or carbon black had a higher activity for hydrocracking than the corresponding combinations with Fe naphthenate. Selectivity for NMBB cleavage was also different with the two different catalysts. The addition of S increased the activity of Fe naphthenate with waste tire but decreased that of Mo naphthenate. Increased NMBB hydrocracking of 79.9% was obtained by combining Mo naphthenate and carbon black. Combining Fe naphthenate with carbon black or Mo naphthenate did not increase NMBB hydrocracking compared to the values obtained with the individual materials.

  14. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, January 1, 1991--March 31, 1991

    SciTech Connect

    Not Available

    1991-09-01

    The program objective is to generate ultra-fine catalyst particles (20 to 400 {Angstrom} in size) and quantify their potential for improving coal dissolution in the solubilization stage of two-stage catalytic-catalytic liquefaction systems. In the first quarterly report for this program the concept behind our approach was detailed, the structure of the program was presented, key technical issues were identified, preliminary designs were outlined, and technical progress was discussed. All progress made during the second quarter of this program related to experiment design of the proposed supercritical expansion technique for generating ultra-fine, iron compound, catalyst particles. This second quarterly report, therefore, presents descriptions of the final designs for most system components; diagnostic approaches and designs for determining particles size and size distributions, and the composition of the pre-expansion supercritical solution; and the overall technique progress made during this reporting period. 6 refs., 15 figs., 1 tab.

  15. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, October 25, 1990--October 24, 1991: Draft

    SciTech Connect

    Klein, M.T.

    1991-12-30

    The purpose of this work is to investigate the kinetics-assisted design, synthesis and characterization of fme-pardcle, unsupported catalysts for coal liquefaction. The goal is to develop a fundamental understanding of coal catalysis and catalysts that will, in turn, allow for the specification of a novel optimal catalyst for coal liquefaction.

  16. Study of finely divided aqueous systems as an aid to understanding the formation mechanism of polar stratospheric clouds: Case of HNO3/H2O and H2SO4/H2O systems

    NASA Astrophysics Data System (ADS)

    Bogdan, A.; Molina, M. J.; Kulmala, M.; MacKenzie, A. R.; Laaksonen, A.

    2003-05-01

    The study of nanometer-scale aqueous systems (finely divided aqueous systems (FDAS)) can be achieved using the absorption of vapors on fumed silica (SiO2) powder. Being a product of flame synthesis technology, fumed silica particles (6-11 nm) can be considered to be analogous to the silica smoke particles of anthropogenic and extraterrestrial origin that are supposed to be widely present in the stratosphere and mesosphere. Here, we describe the freezing and melting behavior of nanometer-scale pure H2O and binary HNO3/H2O and H2SO4/H2O systems of varying acid content, using differential scanning calorimetry (DSC). Besides reductions of melting temperature, Tm, large reductions in freezing and melting enthalpies, with ΔHf < ΔHm, in comparison with bulk solutions have also been detected. Experiments showed that fumed silica can serve as a freezing nucleus for heterogeneous ice nucleation from dilute HNO3/H2O droplets. The onset of freezing of a silica/HNO3/H2O sample with HNO3/H2O stoichiometry close to that of NAT (53 ± 5 wt % HNO3) at temperatures ≈7 K warmer than the ice frost point suggests that silica particles can promote heterogeneous freezing of nitric acid hydrates in the stratosphere. Freezing of bulk droplets (53.2 wt % HNO3) supported on Al substrate at temperatures warmer than -73°C (200 K) suggests that in principle, Al2O3 surface may induce freezing of HNO3 hydrates as well. DSC measurements performed on the silica/H2SO4/H2O nanosystem showed that at stratospheric temperatures, silica particles cannot induce heterogeneous formation of sulfuric acid hydrates.

  17. Method for dispersing catalyst onto particulate material

    DOEpatents

    Utz, Bruce R.; Cugini, Anthony V.

    1992-01-01

    A method for dispersing finely divided catalyst precursors onto the surface of coal or other particulate material includes the steps of forming a wet paste mixture of the particulate material and a liquid solution containing a dissolved transition metal salt, for instance a solution of ferric nitrate. The wet paste mixture is in a state of incipient wetness with all of this solution adsorbed onto the surfaces of the particulate material without the presence of free moisture. On adding a precipitating agent such as ammonia, a catalyst precursor such as hydrated iron oxide is deposited on the surfaces of the coal. The catalyst is activated by converting it to the sulfide form for the hydrogenation or direct liquefaction of the coal.

  18. Injection technology to recover nickel and cobalt from spent catalysts

    SciTech Connect

    Thapliyal, P.; Zhao, Y.F.; Irons, G.A.

    1996-12-31

    The petroleum refining industry generates over a million tons of spent catalyst per year, containing valuable metals. Currently, these materials are recycled to smelting furnaces, but the fundamental mechanisms controlling the recovery processes are poorly understood. Furthermore, submerged injection of finely divided materials is potentially a means to obtain high recoveries of pay metals. In this study, a catalyst containing 10% Ni and 1% Co was injected into 45 kg heats of matte. A copper matte was chosen so that the nickel and cobalt recoveries were measurable. It was found that the recovery ranged from 40 to 70%, increasing with catalyst feed rate, decreasing with catalyst particle size and decreasing with the oxygen content of the carrier gas. A mathematical model was developed to account for the results, and to permit extrapolation to nickel mattes. The industrial implications are discussed. 7 refs., 7 figs., 4 tabs.

  19. Process and catalyst for the hydrogenation of coal

    SciTech Connect

    Wernicke, H.J.; Zimmerman, H.

    1985-05-07

    Blast furnace flue dust is used as a catalyst in a process for the hydrogenation of coal. A flowable mixture of finely divided coal particles and liquid hydrocarbons is brought to high pressure and to reaction temperature. The mixture is hydrogenated with hydrogen in the presence of blast furnace dust as a hydrogenation catalyst. The cost-effective hydrogenation catalyst is reused profitably subsequent to application in the coal hydrogenation process. Gaseous products are separated from liquid and solid reaction products. Liquid products are vaporized and are fractionated under atmospheric pressure and under vacuum. Hydrogen for use in the hydrogenation is produced by partial oxidation of the residue, and the catalyst is deposited as slag, which is returned to the blast furnace.

  20. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, April 26, 1991--July 26, 1991: Draft

    SciTech Connect

    Klein, M.T.

    1991-09-11

    A series of carbonyl-based homogeneous catalyst precursors has been prepared. These species include: Fe(CO){sub 4}PPh{sub 3}, Fe(CO){sub 3}(PPh{sub 3}){sub 2}, Fe(CO){sub 2}(PPh{sub 3}){sub 2}CS{sub 2}, S{sub 2}Fe{sub 2}(CO){sub 6}, S{sub 2}Fe{sub 3}(CO){sub 9}. Fe(CO){sub 4}PPh{sub 3} was prepared by a combined photochemical and thermal route from triphenylphosphine (PPh{sub 3}) in iron pentacarbonyl (Fe(CO){sub 5}). This preparation procedure, which is selective to the monosubstituted product, is outlined herein. Currently these compounds are being tested as catalysts/catalyst precursors with coal or model compounds in the tubing bomb reactors to provide information relating catalytic activity to catalyst structure and properties. (VC)

  1. Optimization of reaction conditions in selective oxidation of styrene over fine crystallite spinel-type CaFe{sub 2}O{sub 4} complex oxide catalyst

    SciTech Connect

    Pardeshi, Satish K.; Pawar, Ravindra Y.

    2010-05-15

    The CaFe{sub 2}O{sub 4} spinel-type catalyst was synthesized by citrate gel method and well characterized by thermogravimetric analysis, atomic absorption spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction and transmission electron microscopy. The crystallization temperature of the spinel particle prepared by citrate gel method was 600 {sup o}C which was lower than that of ferrite prepared by other methods. CaFe{sub 2}O{sub 4} catalysts prepared by citrate gel method show better activity for styrene oxidation in the presence of dilute H{sub 2}O{sub 2} (30%) as an oxidizing agent. In this reaction the oxidative cleavage of carbon-carbon double bond of styrene takes place selectively with 38 {+-} 2 mol% conversion. The major product of the reaction is benzaldehyde up to 91 {+-} 2 mol% and minor product phenyl acetaldehyde up to 9 {+-} 2 mol%, respectively. The products obtained in the styrene oxidation reaction were analyzed by gas chromatography and mass spectroscopy. The influence of the catalyst, reaction time, temperature, amount of catalyst, styrene/H{sub 2}O{sub 2} molar ratio and solvents on the conversion and product distribution were studied.

  2. Timing divided attention.

    PubMed

    Hogendoorn, Hinze; Carlson, Thomas A; VanRullen, Rufin; Verstraten, Frans A J

    2010-11-01

    Visual attention can be divided over multiple objects or locations. However, there is no single theoretical framework within which the effects of dividing attention can be interpreted. In order to develop such a model, here we manipulated the stage of visual processing at which attention was divided, while simultaneously probing the costs of dividing attention on two dimensions. We show that dividing attention incurs dissociable time and precision costs, which depend on whether attention is divided during monitoring or during access. Dividing attention during monitoring resulted in progressively delayed access to attended locations as additional locations were monitored, as well as a one-off precision cost. When dividing attention during access, time costs were systematically lower at one of the accessed locations than at the other, indicating that divided attention during access, in fact, involves rapid sequential allocation of undivided attention. We propose a model in which divided attention is understood as the simultaneous parallel preparation and subsequent sequential execution of multiple shifts of undivided attention. This interpretation has the potential to bring together diverse findings from both the divided-attention and saccade preparation literature and provides a framework within which to integrate the broad spectrum of divided-attention methodologies.

  3. Borosilicate-containing catalyst and reforming processes employing same

    SciTech Connect

    Unmuth, E.E.; Gutberlet, L.C.

    1986-04-22

    A process is described for the reforming of a hydrocarbon stream, which comprises contacting the hydrocarbon stream in a first reforming zone in the presence of hydrogen and under reforming conditions with a first catalyst to provide a partially-reformed effluent and contacting the partially-reformed effluent in a second reforming zone under reforming conditions and in the presence of hydrogen with a second catalyst to provide a reformed effluent having a high octane number. The first catalyst consists of at least one noble metal of Group VIII of the Periodic Table of Elements and a combined halogen on a porous, refractory inorganic oxide support. The second catalyst consists of a physical particle-form mixture of a Component A and a Component B. The Component A consists of at least one noble metal of Group VIII deposed on a solid catalyst support material providing acidic catalytic sites. The Component B consists of essentially of a crystalline borosilicate molecular sieve, the catalyst having been prepared by thoroughly and intimately blending finely-divided particles of the Components A and B to provide a thoroughly-blended composite, and the Component B being present in an amount within the range of about 0.1 wt% to about 25 wt%, based upon the weight of the second catalyst.

  4. New catalysts for coal liquefaction and new nanocrystalline catalysts synthesis methods

    SciTech Connect

    Linehan, J.C.; Matson, D.W.; Darab, J.G.

    1994-09-01

    The use of coal as a source of transportation fuel is currently economically unfavorable due to an abundant world petroleum supply and the relatively high cost of coal liquefaction. Consequently, a reduction in the cost of coal liquefaction, for example by using less and/or less costly catalysts or lower liquefaction temperatures, must be accomplished if coal is to play an significant role as a source of liquid feedstock for the petrochemical industry. The authors and others have investigated the applicability of using inexpensive iron-based catalysts in place of more costly and environmentally hazardous metal catalysts for direct coal liquefaction. Iron-based catalysts can be effective in liquefying coal and in promoting carbon-carbon bond cleavage in model compounds. The authors have been involved in an ongoing effort to develop and optimize iron-based powders for use in coal liquefaction and related petrochemical applications. Research efforts in this area have been directed at three general areas. The authors have explored ways to optimize the effectiveness of catalyst precursor species through use of nanocrystalline materials and/or finely divided powders. In this effort, the authors have developed two new nanophase material production techniques, Modified Reverse Micelle (MRM) and the Rapid Thermal Decomposition of precursors in Solution (RTDS). A second effort has been aimed at optimizing the effectiveness of catalysts by variations in other factors. To this, the authors have investigated the effect that the crystalline phase has on the capacity of iron-based oxide and oxyhydroxide powders to be effectively converted to an active catalyst phase under liquefaction conditions. And finally, the authors have developed methods to produce active catalyst precursor powders in quantities sufficient for pilot-scale testing. Major results in these three areas are summarized.

  5. Method for dispersing catalyst onto particulate material and product thereof

    DOEpatents

    Utz, Bruce R.; Cugini, Anthony V.

    1992-01-01

    A method for dispersing finely divided catalyst precursors onto the surface of coal or other particulate material includes the steps of forming a wet paste mixture of the particulate material and a liquid solution containing a dissolved transition metal salt, for instance a solution of ferric nitrate. The wet paste mixture is in a state of incipient wetness with all of this solution adsorbed onto the surfaces of the particulate material without the presence of free moisture. On adding a precipitating agent such as ammonia, a catalyst precursor such as hydrated iron oxide is deposited on the surfaces of the coal. The catalyst is activated by converting it to the sulfide form for the hydrogenation or direct liquefaction of the coal.

  6. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, October 26, 1990--January 26, 1991: Draft

    SciTech Connect

    Klein, M.T.

    1991-02-22

    The first task in our proposed study of catalysts for coal liquefaction was to prepare ultrafine dispersed metal sulfide particles by reactive precipitation from solutions of appropriate metal precursors. At this point, equipment to allow us to prepare these air-sensitive materials in an anaerobic environment has been acquired and assembled. Initial experiments aimed at synthesizing iron sulfide particles have been initiated. As part of the investigation of short contact time catalytic coal liquefaction, initial efforts focused on the noncatalytic pyrolysis reactions of coal and a model compound, Dibenzyl ether (DBE). Two different reactor configurations were examined; catalytic experiments are planned for the coming month.

  7. Oxidation catalyst

    DOEpatents

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  8. Controlled oxidation of remote sp3 C—H bonds in artemisinin via P450 catalysts with fine tuned regio and stereoselectivity

    PubMed Central

    Zhang, Kaidong; Shafer, Brian M.; Demars, Matthew D.; Stern, Harry A.; Fasan, Rudi

    2012-01-01

    The selective oxyfunctionalization of isolated sp3 C—H bonds in complex molecules represents a formidable challenge in organic chemistry. Here, we describe a rational, systematic strategy to expedite the development of P450 oxidation catalysts with refined regio and stereoselectivity for the hydroxylation of remote, unactivated C—H sites in a complex scaffold. Using artemisinin as model substrate, we demonstrate how a three tier strategy involving first sphere active site mutagenesis, high throughput P450 fingerprinting, and fingerprint driven P450 reactivity predictions enabled the rapid evolution of three efficient biocatalysts for the selective hydroxylation of a primary and a secondary C—H site (with both S and R stereoselectivity) in a relevant yet previously inaccessible region of this complex natural product. The evolved P450 variants could be applied to provide direct access to the desired hydroxylated derivatives at preparative scales (0.4 g) and in high isolated yields (>90%), thereby enabling further elaboration of this molecule. As an example, enantiopure C7 fluorinated derivatives of the clinical antimalarial drugs artesunate and artemether, in which a major metabolically sensitive site is protected by means of a C—H to C—F substitution, were afforded via P450 mediated chemoenzymatic synthesis. PMID:23121379

  9. The nondeterministic divide

    NASA Technical Reports Server (NTRS)

    Charlesworth, Arthur

    1990-01-01

    The nondeterministic divide partitions a vector into two non-empty slices by allowing the point of division to be chosen nondeterministically. Support for high-level divide-and-conquer programming provided by the nondeterministic divide is investigated. A diva algorithm is a recursive divide-and-conquer sequential algorithm on one or more vectors of the same range, whose division point for a new pair of recursive calls is chosen nondeterministically before any computation is performed and whose recursive calls are made immediately after the choice of division point; also, access to vector components is only permitted during activations in which the vector parameters have unit length. The notion of diva algorithm is formulated precisely as a diva call, a restricted call on a sequential procedure. Diva calls are proven to be intimately related to associativity. Numerous applications of diva calls are given and strategies are described for translating a diva call into code for a variety of parallel computers. Thus diva algorithms separate logical correctness concerns from implementation concerns.

  10. Crossing the phantom divide

    SciTech Connect

    Kunz, Martin; Sapone, Domenico

    2006-12-15

    We consider fluid perturbations close to the 'phantom divide' characterized by p=-{rho} and discuss the conditions under which divergencies in the perturbations can be avoided. We find that the behavior of the perturbations depends crucially on the prescription for the pressure perturbation {delta}p. The pressure perturbation is usually defined using the dark energy rest-frame, but we show that this frame becomes unphysical at the divide. If the pressure perturbation is kept finite in any other frame, then the phantom divide can be crossed. Our findings are important for generalized fluid dark energy used in data analysis (since current cosmological data sets indicate that the dark energy is characterized by p{approx_equal}-{rho} so that p<-{rho} cannot be excluded) as well as for any models crossing the phantom divide, like some modified gravity, coupled dark energy, and braneworld models. We also illustrate the results by an explicit calculation for the 'Quintom' case with two scalar fields.

  11. A Hill Divided

    NASA Image and Video Library

    2015-12-07

    This image captured by NASA 2001 Mars Odyssey spacecraft shows an elevated group of hills east of Phlegra Montes. This highland is divided by a linear channel that is most likely of tectonic origin. Orbit Number: 61195 Latitude: 31.5513 Longitude: 167.142 Instrument: VIS Captured: 2015-09-30 13:26 http://photojournal.jpl.nasa.gov/catalog/PIA20109

  12. The Great Divide

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2005-01-01

    Steps away from where a concrete wall once divided this city east from west, a group of Muslim 1st graders at E.O. Plauen Elementary School sing a phrase that is unfamiliar to most German ears. Though the Roman Catholic and Protestant churches have long provided voluntary religion classes in Berlin schools, only recently have the courts allowed an…

  13. The Great Divide

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2005-01-01

    Steps away from where a concrete wall once divided this city east from west, a group of Muslim 1st graders at E.O. Plauen Elementary School sing a phrase that is unfamiliar to most German ears. Though the Roman Catholic and Protestant churches have long provided voluntary religion classes in Berlin schools, only recently have the courts allowed an…

  14. Crossing the divide

    Treesearch

    Florence Rose Shepard

    2007-01-01

    “This is a divide.” Dad delivered this proclamation with the verve of a discoverer. This memory from childhood frequently surfaces as I struggle to interpret the topology, the complicated relationship between the topography and cultural history of my home, the Green River Basin, that great expanse of sagebrush/ bunchgrass steppe crowned with wilderness.

  15. Photocatalytic H2 Evolution Using Different Commercial TiO2 Catalysts Deposited with Finely Size-Tailored Au Nanoparticles: Critical Dependence on Au Particle Size

    PubMed Central

    Kmetykó, Ákos; Mogyorósi, Károly; Pusztai, Péter; Radu, Teodora; Kónya, Zoltán; Dombi, András; Hernádi, Klára

    2014-01-01

    One weight percent of differently sized Au nanoparticles were deposited on two commercially available TiO2 photocatalysts: Aeroxide P25 and Kronos Vlp7000. The primary objective was to investigate the influence of the noble metal particle size and the deposition method on the photocatalytic activity. The developed synthesis method involves a simple approach for the preparation of finely-tuned Au particles through variation of the concentration of the stabilizing agent. Au was deposited on the TiO2 surface by photo- or chemical reduction, using trisodium citrate as a size-tailoring agent. The Au-TiO2 composites were synthetized by in situ reduction or by mixing the titania suspension with a previously prepared gold sol. The H2 production activities of the samples were studied in aqueous TiO2 suspensions irradiated with near-UV light in the absence of dissolved O2, with oxalic acid or methanol as the sacrificial agent. The H2 evolution rates proved to be strongly dependent on Au particle size: the highest H2 production rate was achieved when the Au particles measured ~6 nm. PMID:28788264

  16. Photocatalytic H₂ Evolution Using Different Commercial TiO₂ Catalysts Deposited with Finely Size-Tailored Au Nanoparticles: Critical Dependence on Au Particle Size.

    PubMed

    Kmetykó, Ákos; Mogyorósi, Károly; Pusztai, Péter; Radu, Teodora; Kónya, Zoltán; Dombi, András; Hernádi, Klára

    2014-11-26

    One weight percent of differently sized Au nanoparticles were deposited on two commercially available TiO₂ photocatalysts: Aeroxide P25 and Kronos Vlp7000. The primary objective was to investigate the influence of the noble metal particle size and the deposition method on the photocatalytic activity. The developed synthesis method involves a simple approach for the preparation of finely-tuned Au particles through variation of the concentration of the stabilizing agent. Au was deposited on the TiO₂ surface by photo- or chemical reduction, using trisodium citrate as a size-tailoring agent. The Au-TiO₂ composites were synthetized by in situ reduction or by mixing the titania suspension with a previously prepared gold sol. The H₂ production activities of the samples were studied in aqueous TiO₂ suspensions irradiated with near-UV light in the absence of dissolved O₂, with oxalic acid or methanol as the sacrificial agent. The H₂ evolution rates proved to be strongly dependent on Au particle size: the highest H₂ production rate was achieved when the Au particles measured ~6 nm.

  17. Highly Dispersed Metal Catalyst for Fuel Cell Electrodes

    SciTech Connect

    2009-03-01

    This factsheet describes a study that will bring industrial catalyst experience to fuel cell research. Specifically, industrial catalysts, such as those used in platforming, utilize precious metal platinum as an active component in a finely dispersed form.

  18. Melting the Divide

    NASA Astrophysics Data System (ADS)

    Gibson, S. M.

    2014-12-01

    Presenting Quaternary Environmental Change to students who fall into Widening Participation criteria at the University of Cambridge, gives a unique opportunity to present academic debate in an approachable and entertaining way. Literally by discussing the melting of our ice caps, melts the divide Cambridge has between its reputation and the reality for the brightest, underprivileged, students. There is a balance between presenting cutting edge research with the need to come across as accessible (and importantly valuable to "learning"). Climate change over the Quaternary lends itself well to this aim. By lecturing groups of potential students through the entire Quaternary in an hour, stopping to discuss how our ancestors interacted with past Interglacials and what are the mechanisms driving change (in generalized terms), you are able to introduce cutting edge research (such as the latest NEEM ice core) to the students. This shows the evolution and importance of higher education and academic research. The lecture leads well onto group discussions (termed "supervisions" in Cambridge), to explore their opinions on the concern for present Anthropogenic Climate Change in relation to Past Climate Change after being presented with images that our ancestors "made it". Here discussion thrives off students saying obvious things (or sarcastic comments!) which quickly can lead into a deep technical discussion on their terms. Such discussions give the students a zest for higher education, simply throwing Ruddiman's (2003) "The Anthroprocene Started Several Thousand Years Ago" at them, questions in a second their concept of Anthropogenic Climate Change. Supervisions lend themselves well to bright, articulate, students and by offering these experiences to students of Widening Participation criteria we quickly melt the divide between the reputation of Cambridge ( and higher education as a whole) and the day to day practice. Higher education is not for the privileged, but a free and

  19. Divided electrochemical cell assembly

    SciTech Connect

    King, Ch. J. H.

    1985-02-19

    A divided electrochemical cell assembly comprises stacked bipolar substantially square parallel planar electrodes and membranes. The corners and edges of the electrodes with bordering insulative spacers in juxtaposition with the chamber walls define four electrolyte circulation manifolds. Anolyte and catholyte channeling means permit the separate introduction of anolyte and catholyte into two of the manifolds and the withdrawal of anolyte and catholyte separately from at least two other manifolds. The electrodes and membranes are separated from one another by the insulative spacers which are also channeling means disposed to provide electrolyte channels across the interfaces of adjacent electrodes and membranes.

  20. Monitoring the Digital Divide

    SciTech Connect

    Cottrell, Les

    2003-05-28

    It is increasingly important to support the large numbers of scientists working in remote areas and having low bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste, a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent ''Recommendations of Trieste'' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work.

  1. PULSE RATE DIVIDER

    DOEpatents

    McDonald, H.C. Jr.

    1962-12-18

    A compact pulse-rate divider circuit affording low impedance output and high input pulse repetition rates is described. The circuit features a single secondary emission tube having a capacitor interposed between its dynode and its control grid. An output pulse is produced at the anode of the tube each time an incoming pulse at the control grid drives the tube above cutoff and the duration of each output pulse corresponds to the charging time of the capacitor. Pulses incoming during the time the grid bias established by the discharging capacitor is sufficiently negative that the pulses are unable to drive the tube above cutoff do not produce output pulses at the anode; these pulses are lost and a dividing action is thus produced by the circuit. The time constant of the discharge path may be vanied to vary in turn the division ratio of the circuit; the time constant of the charging circuit may be varied to vary the width of the output pulses. (AEC)

  2. Laser dividing apparatus

    DOEpatents

    English, Jr., R. Edward; Johnson, Steve A.

    1995-01-01

    A laser beam dividing apparatus (10) having a first beam splitter (14) with an aperture (16) therein positioned in the path of a laser beam (12) such that a portion of the laser beam (12) passes through the aperture (16) onto a second beam splitter (20) and a portion of the laser beam (12) impinges upon the first beam splitter (14). Both the first beam splitter (14) and the second beam splitter (20) are, optionally, made from a dichroic material such that a green component (24) of the laser beam (12) is reflected therefrom and a yellow component (26) is refracted therethrough. The first beam splitter (14) and the second beam splitter (20) further each have a plurality of facets (22) such that the components (24, 26) are reflected and refracted in a number equaling the number of facets (22).

  3. Why do bacteria divide?

    PubMed Central

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life – Life as independent of its constituents – is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass – its cellular connectivity – would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity – Life on the Scales of Equilibria – is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias ‘hyperstructures.’ The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence – Competitive Coherence – is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell’s contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself. PMID

  4. Challenging the Digital Divide

    NASA Astrophysics Data System (ADS)

    Kembhavi, Ajit

    2006-08-01

    Vast quantities of astronomical data in the form of images, spectra and catalogues are now freely available over the internet, and tools for producing science from these resources are also becoming available, particularly through the emerging Virtual Observatories. In addition to this, most astronomical literature from research journals is available at no cost through the ADS and preprint service. This situation, in principle, provides equal opportunity to astronomers located anywhere in the world to participate in the process of discovery. The only requirement is that the astronomers have access to the internet, and a fertile imagination. But in the real world, astronomers in many countries have very limited bandwidth and computing power, and are therefore excluded from meaningful participation in astronomical research, even though they may have the ideas and experience to contribute substantially to the effort. The lack of connectivity and computing hardware also makes it difficult for astronomers in many countries from exposing adequately any data resources that they may have produced locally. This situation prevents many aspiring and experienced astronomers from reaching their creative potential, and from attracting young persons to the charms of modern astronomy; it also leads to opportunity loss to astronomy, as it loses out on the the human resources and fresh ideas and talents which astronomers from developing countries could bring to the subject. I will discuss in my talk the nature and extent of this digital divide, the ways in which it could be mitigated, and the benefits which would arise from the unification. I will base some of my discussion on my experiences in setting up a major programme to take the advantages of the internet revolution to hundreds of universities in India.

  5. Supported molten-metal catalysts

    DOEpatents

    Datta, Ravindra; Singh, Ajeet; Halasz, Istvan; Serban, Manuela

    2001-01-01

    An entirely new class of catalysts called supported molten-metal catalysts, SMMC, which can replace some of the existing precious metal catalysts used in the production of fuels, commodity chemicals, and fine chemicals, as well as in combating pollution. SMMC are based on supporting ultra-thin films or micro-droplets of the relatively low-melting (<600.degree. C.), inexpensive, and abundant metals and semimetals from groups 1, 12, 13, 14, 15 and 16, of the periodic table, or their alloys and intermetallic compounds, on porous refractory supports, much like supported microcrystallites of the traditional solid metal catalysts. It thus provides orders of magnitude higher surface area than is obtainable in conventional reactors containing molten metals in pool form and also avoids corrosion. These have so far been the chief stumbling blocks in the application of molten metal catalysts.

  6. Reforming with a catalyst containing a group VIII noble metal a group VIII non-noble metal and gallium on separate support particles

    SciTech Connect

    Sorrentino, C. M.; Bertolacini, R. J.; Pellet, R. J.

    1984-11-13

    The catalyst comprises a physical particle-form mixture of a Componet A, a Component B, and a Component C, said Component A comprising at least one Group VIII noble metal, preferably platinum, deposed on a solid catalyst support material providing acidic catalytic sites, said Component B comprising a small amount of a non-noble metal of Group VIII selected from cobalt, nickel, and mixtures thereof, preferably cobalt, on a solid catalyst support material providing acidic catalytic sites, said Component C comprising a small amount of gallium deposed on a solid catalyst support material providing acidic catalytic sites, and said catalyst having been prepared by thoroughly and intimately blending finely-divided particles of said Component A, B, and C to provide a thoroughly-blended composite. The catalyst can be employed suitably in a hydrocarbon conversion process. In particular, the catalyst can be employed in a process for the reforming of a hydrocarbon stream, which process comprises contacting said stream in a reforming zone under reforming conditions and in the presence of hydrogen with said catalyst. The process can be used advantageously to reform a hydrocarbon stream that contains up to 80 ppm sulfur.

  7. Reforming catalysts

    SciTech Connect

    Givens, E.N.; Plank, C.J.; Rosinski, E.J.

    1980-03-04

    Crystalline aluminosilicate zeolites are mixed with conventional reforming catalysts to produce new catalytic compositions with high catalytic activity and selectivity and excellent aging characteristics. These new catalytic compositions may be utilized alone or in conjunction with conventional reforming catalysts. The acidic activity of the total catalyst system is controlled within defined limits. When so controlled the utility of these catalyst systems in reforming hydrocarbon mixtures is to reduce the C1 and C2 concentrations in reformer gas product, while increasing the C3 and C4 concentrations and maintaining high liquid yield at high octane numbers.

  8. Self-regeneration of a Pd-perovskite catalyst for automotive emissions control

    NASA Astrophysics Data System (ADS)

    Nishihata, Y.; Mizuki, J.; Akao, T.; Tanaka, H.; Uenishi, M.; Kimura, M.; Okamoto, T.; Hamada, N.

    2002-07-01

    Catalytic converters are widely used to reduce the amounts of nitrogen oxides, carbon monoxide and unburned hydrocarbons in automotive emissions. The catalysts are finely divided precious-metal particles dispersed on a solid support. During vehicle use, the converter is exposed to heat, which causes the metal particles to agglomerate and grow, and their overall surface area to decrease. As a result, catalyst activity deteriorates. The problem has been exacerbated in recent years by the trend to install catalytic converters closer to the engine, which ensures immediate activation of the catalyst on engine start-up, but also places demanding requirements on the catalyst's heat resistance. Conventional catalyst systems thus incorporate a sufficient excess of precious metal to guarantee continuous catalytic activity for vehicle use over 50,000miles (80,000km). Here we use X-ray diffraction and absorption to show that LaFe0.57Co0.38Pd0.05O3, one of the perovskite-based catalysts investigated for catalytic converter applications since the early 1970s, retains its high metal dispersion owing to structural responses to the fluctuations in exhaust-gas composition that occur in state-of-the-art petrol engines. We find that as the catalyst is cycled between oxidative and reductive atmospheres typically encountered in exhaust gas, palladium (Pd) reversibly moves into and out of the perovskite lattice. This movement appears to suppress the growth of metallic Pd particles, and hence explains the retention of high catalyst activity during long-term use and ageing.

  9. Bimetallic Catalysts.

    ERIC Educational Resources Information Center

    Sinfelt, John H.

    1985-01-01

    Chemical reaction rates can be controlled by varying composition of miniscule clusters of metal atoms. These bimetallic catalysts have had major impact on petroleum refining, where work has involved heterogeneous catalysis (reacting molecules in a phase separate from catalyst.) Experimentation involving hydrocarbon reactions, catalytic…

  10. Bimetallic Catalysts.

    ERIC Educational Resources Information Center

    Sinfelt, John H.

    1985-01-01

    Chemical reaction rates can be controlled by varying composition of miniscule clusters of metal atoms. These bimetallic catalysts have had major impact on petroleum refining, where work has involved heterogeneous catalysis (reacting molecules in a phase separate from catalyst.) Experimentation involving hydrocarbon reactions, catalytic…

  11. Essays on the Digital Divide

    ERIC Educational Resources Information Center

    Abdelfattah, Belal M. T.

    2013-01-01

    The digital divide is a phenomenon that is globally persistent, despite rapidly decreasing costs in technology. While much of the variance in the adoption and use of information communication technology (ICT) that defines the digital divide can be explained by socioeconomic and demographic variables, there is still significant unaccounted variance…

  12. Oxyhydrochlorination catalyst

    DOEpatents

    Taylor, Charles E.; Noceti, Richard P.

    1992-01-01

    An improved catalyst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HCl and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride.

  13. Continuous bench-scale slurry catalyst testing: Direct coal liquefaction of rawhide sub-bituminous coal. Final topical report, June 1994--December 1994

    SciTech Connect

    Coless, L.A.; Poole, M.C.; Wen, M.Y.

    1995-11-21

    Supported catalysts, either in fixed bed or ebullating bed reactors, are subject to deactivation with time, especially if the feed contains deactivating species, such as metals and coke precursors. Dispersed catalyst systems avoid significant catalyst deactivation because there are no catalyst pores to plug, hence no pore mouth plugging, and hopefully, no relevant decline of catalyst surface area or pore volume. The tests carried out in 1994, at the Exxon Research and Development Laboratories (ERDL) for DOE covered a slate of 5 dispersed catalysts for direct coal liquefaction of Rawhide sub-bituminous coal, which is similar to the Black Thunder coal tested earlier at Wilsonville. The catalysts included three iron and two molybdenum types. The Bailey iron oxide and the two molybdenum catalysts have previously been tested in DOE-sponsored research. These known catalysts will be used to help provide a base line and tie-in to previous work. The two new catalysts, Bayferrox PK 5210 and Mach-1`s Nanocat are very finely divided iron oxides. The iron oxide addition rate was varied from 1.0 to 0.25 wt % (dry coal basis) but the molybdenum addition rate remained constant at 100 wppm throughout the experiments. The effect of changing recycle rate, sulfur and iron oxide addition rates, first stage reactor temperature, mass velocity and catalyst type were tested in the 1994 operations of ERDL`s recycle coal liquefaction unit (RCLU). DOE will use these results to update economics and plan future work. The test program will resume in mid 1995, with another 2-3 months of pilot plant testing.

  14. DNA repair mechanisms in dividing and non-dividing cells.

    PubMed

    Iyama, Teruaki; Wilson, David M

    2013-08-01

    DNA damage created by endogenous or exogenous genotoxic agents can exist in multiple forms, and if allowed to persist, can promote genome instability and directly lead to various human diseases, particularly cancer, neurological abnormalities, immunodeficiency and premature aging. To avoid such deleterious outcomes, cells have evolved an array of DNA repair pathways, which carry out what is typically a multiple-step process to resolve specific DNA lesions and maintain genome integrity. To fully appreciate the biological contributions of the different DNA repair systems, one must keep in mind the cellular context within which they operate. For example, the human body is composed of non-dividing and dividing cell types, including, in the brain, neurons and glial cells. We describe herein the molecular mechanisms of the different DNA repair pathways, and review their roles in non-dividing and dividing cells, with an eye toward how these pathways may regulate the development of neurological disease.

  15. DNA repair mechanisms in dividing and non-dividing cells

    PubMed Central

    Iyama, Teruaki; Wilson, David M.

    2013-01-01

    DNA damage created by endogenous or exogenous genotoxic agents can exist in multiple forms, and if allowed to persist, can promote genome instability and directly lead to various human diseases, particularly cancer, neurological abnormalities, immunodeficiency and premature aging. To avoid such deleterious outcomes, cells have evolved an array of DNA repair pathways, which carry out what is typically a multiple-step process to resolve specific DNA lesions and maintain genome integrity. To fully appreciate the biological contributions of the different DNA repair systems, one must keep in mind the cellular context within they operate. For example, the human body is composed of non-dividing and dividing cell types, including, in the brain, neurons and glial cells. We describe herein the molecular mechanisms of the different DNA repair pathways, and review their roles in non-dividing and dividing cells, with an eye towards how these pathways may regulate the development of neurological disease. PMID:23684800

  16. Fine Arts.

    ERIC Educational Resources Information Center

    Danzer, Gerald A.; Newman, Mark

    1992-01-01

    Discusses the use of fine arts as sources to enrich the study of history. Suggests that such works will serve as barometers of change, examples of cross-cultural influences, and political messages. Includes suggestions of works and artists from different historic periods. (DK)

  17. Fine Arts.

    ERIC Educational Resources Information Center

    Danzer, Gerald A.; Newman, Mark

    1992-01-01

    Discusses the use of fine arts as sources to enrich the study of history. Suggests that such works will serve as barometers of change, examples of cross-cultural influences, and political messages. Includes suggestions of works and artists from different historic periods. (DK)

  18. Novel supports for coal liquefaction catalysts

    SciTech Connect

    Haynes, H.W. Jr.

    1992-01-01

    This research is divided into three parts: (1) Evaluation of Alkaline-Earth-Promoted CoMo/Alumina Catalysts in a Bench Scale Hydrotreater, (2) Development of a Novel Catalytic Coal Liquefaction Microreactor (CCLM) Unit, and (3) Evaluation of Novel Catalyst Preparations for Direct Coal Liquefaction. (VC)

  19. Sociology: The growing climate divide

    NASA Astrophysics Data System (ADS)

    Hoffman, Andrew J.

    2011-07-01

    Climate change has reached the level of a 'scientific consensus', but is not yet a 'social consensus'. New analysis highlights that a growing divide between liberals and conservatives in the American public is a major obstacle to achieving this end.

  20. Catalyst mixtures

    DOEpatents

    Masel, Richard I.; Rosen, Brian A.

    2017-02-14

    Catalysts that include at least one catalytically active element and one helper catalyst can be used to increase the rate or lower the overpotential of chemical reactions. The helper catalyst can simultaneously act as a director molecule, suppressing undesired reactions and thus increasing selectivity toward the desired reaction. These catalysts can be useful for a variety of chemical reactions including, in particular, the electrochemical conversion of CO.sub.2 or formic acid. The catalysts can also suppress H.sub.2 evolution, permitting electrochemical cell operation at potentials below RHE. Chemical processes and devices using the catalysts are also disclosed, including processes to produce CO, OH.sup.-, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, O.sub.2, H.sub.2, (COOH).sub.2, or (COO.sup.-).sub.2, and a specific device, namely, a CO.sub.2 sensor.

  1. Photo-oxidation catalysts

    DOEpatents

    Pitts, J. Roland; Liu, Ping; Smith, R. Davis

    2009-07-14

    Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

  2. Bridging the Health Data Divide

    PubMed Central

    2016-01-01

    Fundamental quality, safety, and cost problems have not been resolved by the increasing digitization of health care. This digitization has progressed alongside the presence of a persistent divide between clinicians, the domain experts, and the technical experts, such as data scientists. The disconnect between clinicians and data scientists translates into a waste of research and health care resources, slow uptake of innovations, and poorer outcomes than are desirable and achievable. The divide can be narrowed by creating a culture of collaboration between these two disciplines, exemplified by events such as datathons. However, in order to more fully and meaningfully bridge the divide, the infrastructure of medical education, publication, and funding processes must evolve to support and enhance a learning health care system. PMID:27998877

  3. Catalyst design for biorefining.

    PubMed

    Wilson, Karen; Lee, Adam F

    2016-02-28

    The quest for sustainable resources to meet the demands of a rapidly rising global population while mitigating the risks of rising CO2 emissions and associated climate change, represents a grand challenge for humanity. Biomass offers the most readily implemented and low-cost solution for sustainable transportation fuels, and the only non-petroleum route to organic molecules for the manufacture of bulk, fine and speciality chemicals and polymers. To be considered truly sustainable, biomass must be derived from resources which do not compete with agricultural land use for food production, or compromise the environment (e.g. via deforestation). Potential feedstocks include waste lignocellulosic or oil-based materials derived from plant or aquatic sources, with the so-called biorefinery concept offering the co-production of biofuels, platform chemicals and energy; analogous to today's petroleum refineries which deliver both high-volume/low-value (e.g. fuels and commodity chemicals) and low-volume/high-value (e.g. fine/speciality chemicals) products, thereby maximizing biomass valorization. This article addresses the challenges to catalytic biomass processing and highlights recent successes in the rational design of heterogeneous catalysts facilitated by advances in nanotechnology and the synthesis of templated porous materials, as well as the use of tailored catalyst surfaces to generate bifunctional solid acid/base materials or tune hydrophobicity.

  4. Dividing Fractions: A Pedagogical Technique

    ERIC Educational Resources Information Center

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  5. Getting Past the "Digital Divide"

    ERIC Educational Resources Information Center

    McCollum, Sean

    2011-01-01

    As most educators know, there is a lot more to addressing the so-called "digital divide" than having enough working machines in classrooms. Effective information technology (IT) in schools requires useful software, reliable and speedy Internet access, effective teacher training, and well-considered goals with transformative outcomes. Educators who…

  6. Dividing Fractions: A Pedagogical Technique

    ERIC Educational Resources Information Center

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  7. Getting Past the "Digital Divide"

    ERIC Educational Resources Information Center

    McCollum, Sean

    2011-01-01

    As most educators know, there is a lot more to addressing the so-called "digital divide" than having enough working machines in classrooms. Effective information technology (IT) in schools requires useful software, reliable and speedy Internet access, effective teacher training, and well-considered goals with transformative outcomes. Educators who…

  8. Getting Past the "Digital Divide"

    ERIC Educational Resources Information Center

    McCollum, Sean

    2011-01-01

    In the last decade, "digital divide" has become a catchphrase for the stubborn disparity in IT resources between communities, especially in regard to education. Low-income, rural and minority populations have received special scrutiny as the technological "have-nots." This article presents success stories of educators who can work around obstacles…

  9. Applications of Neutron Scattering in the Chemical Industry: Proton Dynamics of Highly Dispersed Materials, Characterization of Fuel Cell Catalysts, and Catalysts from Large-Scale Chemical Processes

    NASA Astrophysics Data System (ADS)

    Albers, Peter W.; Parker, Stewart F.

    The attractiveness of neutron scattering techniques for the detailed characterization of materials of high degrees of dispersity and structural complexity as encountered in the chemical industry is discussed. Neutron scattering picks up where other analytical methods leave off because of the physico-chemical properties of finely divided products and materials whose absorption behavior toward electromagnetic radiation and electrical conductivity causes serious problems. This is demonstrated by presenting typical applications from large-scale production technology and industrial catalysis. These include the determination of the proton-related surface chemistry of advanced materials that are used as reinforcing fillers in the manufacture of tires, where interrelations between surface chemistry, rheological properties, improved safety, and significant reduction of fuel consumption are the focus of recent developments. Neutron scattering allows surface science studies of the dissociative adsorption of hydrogen on nanodispersed, supported precious metal particles of fuel cell catalysts under in situ loading at realistic gas pressures of about 1 bar. Insight into the occupation of catalytically relevant surface sites provides valuable information about the catalyst in the working state and supplies essential scientific input for tailoring better catalysts by technologists. The impact of deactivation phenomena on industrial catalysts by coke deposition, chemical transformation of carbonaceous deposits, and other processes in catalytic hydrogenation processes that result in significant shortening of the time of useful operation in large-scale plants can often be traced back in detail to surface or bulk properties of catalysts or materials of catalytic relevance. A better understanding of avoidable or unavoidable aspects of catalyst deactivation phenomena under certain in-process conditions and the development of effective means for reducing deactivation leads to more energy

  10. Highly dispersed metal catalyst

    DOEpatents

    Xiao, Xin; West, William L.; Rhodes, William D.

    2016-11-08

    A supported catalyst having an atomic level single atom structure is provided such that substantially all the catalyst is available for catalytic function. A process of forming a single atom catalyst unto a porous catalyst support is also provided.

  11. Reforming catalyst

    SciTech Connect

    Baird, W.C. Jr.; Swan, G.A.

    1991-11-19

    This patent describes a catalyst useful for reforming a naphtha feed at high severity reforming conditions. It comprises the metals, platinum, rhenium and iridium on a refractory porous inorganic oxide support, the support consisting essentially of alumina, wherein the concentration by weight of each of the metals platinum and rhenium is at least 0.1 percent and iridium at least 0.15 percent and at least one of the metals is present in a concentration of at least 0.3 percent, and the sum-total; concentration of the metals is greater than 0.9 percent, and wherein each catalyst particle contains all three of the metals platinum, rhenium and iridium. This patent also describes this composition wherein the catalyst contains from about 0.1 percent to about 3 percent of a halogen and from about 0.05 percent to about 0.02 percent sulfur.

  12. How Giardia Swim and Divide

    PubMed Central

    Ghosh, Sudip; Frisardi, Marta; Rogers, Rick; Samuelson, John

    2001-01-01

    To determine how binuclear giardia swim, we used video microscopy to observe trophozoites of Giardia intestinalis, which were labeled with an amino-specific Alexa Fluor dye that highlighted the flagella and adherence disc. Giardia swam forward by means of the synchronous beating of anterior, posterolateral, and ventral flagella in the plane of the ventral disc, while caudal flagella swam in a plane perpendicular to the disc. Giardia turned in the plane of the disc by means of a rudder-like motion of its tail, which was constant rather than beating. To determine how giardia divide, we used three-dimensional confocal microscopy, the same surface label, nuclear stains, and antitubulin antibodies. Giardia divided with mirror-image symmetry in the plane of the adherence disc, so that the right nucleus of the mother became the left nucleus of the daughter. Pairs of nuclei were tethered together by microtubules which surrounded nuclei and prevented mother or daughter giardia from receiving two copies of the same nucleus. New adherence discs formed upon a spiral backbone of microtubules, which had a clockwise rotation when viewed from the ventral surface. These dynamic observations of the parasite begin to reveal how giardia swim and divide. PMID:11705969

  13. Synthesis of iron based hydrocracking catalysts

    DOEpatents

    Farcasiu, Malvina; Eldredge, Patricia A.; Ladner, Edward P.

    1993-01-01

    A method of preparing a fine particle iron based hydrocracking catalyst and the catalyst prepared thereby. An iron (III) oxide powder and elemental sulfur are reacted with a liquid hydrogen donor having a hydroaromatic structure present in the range of from about 5 to about 50 times the weight of iron (III) oxide at a temperature in the range of from about 180.degree. C. to about 240.degree. C. for a time in the range of from about 0 to about 8 hours. Various specific hydrogen donors are disclosed. The catalysts are active at low temperature (<350.degree. C.) and low pressure.

  14. Catalyst activator

    DOEpatents

    McAdon, Mark H.; Nickias, Peter N.; Marks, Tobin J.; Schwartz, David J.

    2001-01-01

    A catalyst activator particularly adapted for use in the activation of metal complexes of metals of Group 3-10 for polymerization of ethylenically unsaturated polymerizable monomers, especially olefins, comprising two Group 13 metal or metalloid atoms and a ligand structure including at least one bridging group connecting ligands on the two Group 13 metal or metalloid atoms.

  15. Wealth and the marital divide.

    PubMed

    Schneider, Daniel

    2011-09-01

    Marriage patterns differ dramatically in the United States by race and education. The author identifies a novel explanation for these marital divides, namely, the important role of personal wealth in marriage entry. Using event-history models and data from the National Longitudinal Survey of Youth 1979 cohort, the author shows that wealth is an important predictor of first marriage and that differences in asset ownership by race and education help to explain a significant portion of the race and education gaps in first marriage. The article also tests possible explanations for why wealth plays an important role in first marriage entry.

  16. GALLATIN DIVIDE ROADLESS AREA, MONTANA.

    USGS Publications Warehouse

    Simons, Frank S.; Close, Terry J.

    1984-01-01

    A mineral-resource survey of the Gallatin Divide Roadless Area in the Gallatin Range of southwestern Montana was made. The area has probable and substantiated mineral-resource potential for phosphate rock, but most of the phosphate beds are thin, discontinuous, low grade, and deeply buried. Petrified wood is abundant but is scattered and of poor quality. Oil and gas resources are unlikely because possible productive structures are small and deeply eroded. The roadless area has little promise for the occurrence of other mineral or energy resources.

  17. A house divided cannot stand

    SciTech Connect

    Gilbert, S.M. )

    1994-01-01

    When it comes to the relationships between electric utilities and public service commissions, utilities would do well to remember the words of Abraham Lincoln -- [open quotes]A house divided against itself cannot stand.[close quotes] For just as distrust, dissension, and division threatened the future of the United States during the Civil War, they threaten the future of utilities today.In an effort to lower their costs and increase their competitive advantage, utility companies are increasingly looking to reinvent cultures, reengineer work processes, and redefine corporate missions, values, and strategies. But unless utilities also rebuild regulatory relations, such efforts are doomed to fail. If this prognosis sounds overly simplistic or melodramatic -- especially as utilities appear to be moving toward an era of reduced regulation -- think again. History shows that regulatory relationships drive a utility's ability to successfully integrate demand-side management (DSM) programs that are often critical to business strategies and goals.

  18. Hydrocracking catalyst

    SciTech Connect

    Arias, B.; Galiasso, R.; Kum, H.

    1985-02-12

    The invention relates to a particular method for the preparation of a hydrocracking catalyst, using a high iron content bauxite as a basis. This bauxite is ground and screened to a specific size and mixed with three types of additives: a promoter additive of the P, Mo, Co, Ni, W type. A hardener additive of the phosphoric acid type, ammonium phosphate. And a lubricant and pore-generating additive of the polyvinyl alcohol, polyethylene-glycol, starch type. The particularity consists in that the three additives are added simultaneously during the extrusion of the sample. That way, a particular surface composition is obtained which allows for the activity of the catalyst. Extruded products are obtained in sizes of 1/8, 1/16, and 1/32'' and submitted to drying and calcination programs for their activation. The obtained catalyst offers a good mechanical strength, a high content in macropores and a high activity, specifically for the hydrocracking of heavy Venezuelan crudes or residues.

  19. Adding diffuse reflectance infrared Fourier transform spectroscopy capability to extended x-ray-absorption fine structure in a new cell to study solid catalysts in combination with a modulation approach

    NASA Astrophysics Data System (ADS)

    Chiarello, Gian Luca; Nachtegaal, Maarten; Marchionni, Valentina; Quaroni, Luca; Ferri, Davide

    2014-07-01

    We describe a novel cell used to combine in situ transmission X-ray absorption spectroscopy (XAS) with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) in a single experiment. The novelty of the cell design compared to current examples is that both radiations are passed through an X-ray and IR transparent window in direct contact with the sample. This innovative geometry also offers a wide surface for IR collection. In order to avoid interference from the crystalline IR transparent materials (e.g., CaF2, MgF2, diamond) a 500 μm carbon filled hole is laser drilled in the center of a CaF2 window. The cell is designed to represent a plug flow reactor, has reduced dead volume in order to allow for fast exchange of gases and is therefore suitable for experiments under fast transients, e.g., according to the concentration modulation approach. High quality time-resolved XAS and DRIFTS data of a 2 wt.% Pt/Al2O3 catalyst are obtained in concentration modulation experiments where CO (or H2) pulses are alternated to O2 pulses at 150 °C. We show that additional information can be obtained on the Pt redox dynamic under working conditions thanks to the improved sensitivity given by the modulation approach followed by Phase Sensitive Detection (PSD) analysis. It is anticipated that the design of the novel cell is likely suitable for a number of other in situ spectroscopic and diffraction methods.

  20. The Southern Ocean biogeochemical divide.

    PubMed

    Marinov, I; Gnanadesikan, A; Toggweiler, J R; Sarmiento, J L

    2006-06-22

    Modelling studies have demonstrated that the nutrient and carbon cycles in the Southern Ocean play a central role in setting the air-sea balance of CO(2) and global biological production. Box model studies first pointed out that an increase in nutrient utilization in the high latitudes results in a strong decrease in the atmospheric carbon dioxide partial pressure (pCO2). This early research led to two important ideas: high latitude regions are more important in determining atmospheric pCO2 than low latitudes, despite their much smaller area, and nutrient utilization and atmospheric pCO2 are tightly linked. Subsequent general circulation model simulations show that the Southern Ocean is the most important high latitude region in controlling pre-industrial atmospheric CO(2) because it serves as a lid to a larger volume of the deep ocean. Other studies point out the crucial role of the Southern Ocean in the uptake and storage of anthropogenic carbon dioxide and in controlling global biological production. Here we probe the system to determine whether certain regions of the Southern Ocean are more critical than others for air-sea CO(2) balance and the biological export production, by increasing surface nutrient drawdown in an ocean general circulation model. We demonstrate that atmospheric CO(2) and global biological export production are controlled by different regions of the Southern Ocean. The air-sea balance of carbon dioxide is controlled mainly by the biological pump and circulation in the Antarctic deep-water formation region, whereas global export production is controlled mainly by the biological pump and circulation in the Subantarctic intermediate and mode water formation region. The existence of this biogeochemical divide separating the Antarctic from the Subantarctic suggests that it may be possible for climate change or human intervention to modify one of these without greatly altering the other.

  1. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Gas divider. 1065.248 Section 1065.248... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You may use a gas divider to blend calibration gases. (b) Component requirements. Use a gas divider that...

  2. Cracking catalyst

    SciTech Connect

    Otterstedt, J. E. A.; Jaras, S. G.; Pudas, R.; Upson, L. L.

    1985-05-07

    A cracking catalyst having good resistance to metal poisoning has at least two particle fractions of different particle sizes, the cracking catalyzing zeolite material being concentrated to the coarser particle size fractions, and the finer particle size fractions being formed from material having relatively lower or no or insignificant cracking catalyzing activity. The particles of the finer particle size fractions have a matrix of kaolin and amorphous alumina--silica and may contain for example, an SO /SUB x/ eliminating additive such as Al/sub 2/O/sub 3/, CaO and/or MgO. The coarser particle size fractions having cracking catalyzing effect have a mean particle size of from 80 to 125 ..mu..m and the finer particle size fractions a mean particle size of from 30 to 75 ..mu..m. The coarser particle size fractions have a zeolite content of at least 20 weight % and may have a zeolite content of up to 100 weight %, the remainder consisting essentially of material which has relatively lower or no or insignificant cracking-catalyzing activity and which consists of kaolin and amorphous alumina-silica. The catalyst mass as a whole may have a zeolite content of up to 50 weight %.

  3. Probing the influence of the center atom coordination structure in iron phthalocyanine multi-walled carbon nanotube-based oxygen reduction reaction catalysts by X-ray absorption fine structure spectroscopy

    NASA Astrophysics Data System (ADS)

    Peng, Yingxiang; Li, Zhipan; Xia, Dingguo; Zheng, Lirong; Liao, Yi; Li, Kai; Zuo, Xia

    2015-09-01

    Three different pentacoordinate iron phthalocyanine (FePc) electrocatalysts with an axial ligand (pyridyl group, Py) anchored to multi-walled carbon nanotubes (MWCNTs) are prepared by a microwave method as high performance composite electrocatalysts (FePc-Py/MWCNTs) for the oxygen reduction reaction (ORR). For comparison, tetracoordinate FePc electrocatalysts without an axial ligand anchored to MWCNTs (FePc/MWCNTs) are assembled in the same way. Ultraviolet-visible spectrophotometry (UV-Vis), Raman spectroscopy (RS), and high-resolution transmission electron microscopy (HRTEM) are used to characterize the obtained electrocatalysts. The electrocatalytic activity of the samples is measured by linear sweep voltammetry (LSV), and the onset potential of all of the FePc-Py/MWCNTs electrocatalysts is found to be more positive than that of their FePc/MWCNTs counterparts. X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) spectroscopy are employed to elucidate the relationship between molecular structure and electrocatalytic activity. XPS indicates that higher concentrations of Fe3+ and pyridine-type nitrogen play critical roles in determining the electrocatalytic ORR activity of the samples. XAFS spectroscopy reveals that the FePc-Py/MWCNTs electrocatalysts have a coordination geometry around Fe that is closer to the square pyramidal structure, a higher concentration of Fe3+, and a smaller phthalocyanine ring radius compared with those of FePc/MWCNTs.

  4. Chaos, brain and divided consciousness.

    PubMed

    Bob, Petr

    2007-01-01

    Modern trends in psychology and cognitive neuroscience suggest that applications of nonlinear dynamics, chaos and self-organization seem to be particularly important for research of some fundamental problems regarding mind-brain relationship. Relevant problems among others are formations of memories during alterations of mental states and nature of a barrier that divides mental states, and leads to the process called dissociation. This process is related to a formation of groups of neurons which often synchronize their firing patterns in a unique spatial maner. Central theme of this study is the relationship between level of moving and oscilating mental processes and their neurophysiological substrate. This opens a question about principles of organization of conscious experiences and how these experiences arise in the brain. Chaotic self-organization provides a unique theoretical and experimental tool for deeper understanding of dissociative phenomena and enables to study how dissociative phenomena can be linked to epileptiform discharges which are related to various forms of psychological and somatic manifestations. Organizing principles that constitute human consciousness and other mental phenomena from this point of view may be described by analysis and reconstruction of underlying dynamics of psychological or psychophysiological measures. These nonlinear methods in this study were used for analysis of characteristic changes in EEG and bilateral electrodermal activity (EDA) during reliving of dissociated traumatic and stressful memories and during psychopathological states. Analysis confirms a possible role of chaotic transitions in the processing of dissociated memory. Supportive finding for a possible chaotic process related to dissociation found in this study represent also significant relationship of dissociation, epileptiform discharges measured by typical psychopathological manifestations and characteristic laterality changes in bilateral EDA in patients

  5. STUDY OF SOLVENT AND CATALYST INTERACTIONS IN DIRECT COAL LIQUEFACTION

    SciTech Connect

    Michael T. Klein

    1998-10-01

    Major objectives of the present project are to develop a better understanding of the roles of the catalyst and the liquefaction solvent in the coal liquefaction process. An open question concerning the role of the catalyst is whether intimate contact between the catalyst and the coal particles is important or required. To answer this question, it had been planned to coat an active catalyst with a porous silica coating which was found to retain catalyst activity while preventing actual contact between catalyst and coal. Consultation with people in DuPont who coat catalysts for increasing abrasion resistance have indicated that only portions of the catalyst are coated by their process (spray drying) and that sections of uncoated catalyst remain. For that reason, it was decided to suspend the catalyst in a basket separated from the coal in the reactor. The basket walls were to be permeable to the liquefaction solvent but not to the coal particles. Several such baskets were constructed of stainless steel with holes which would not permit passage of coal particles larger than 30 mesh. Liquefactions run with the coal of greater than 30 mesh size gave normal conversion of coal to liquid in the absence of catalyst in the basket, but substantially increased conversion when Ni/Mo on alumina catalyst was in the basket. While this result is interesting and suggestive of some kind of mass transfer of soluble material occurring between the catalyst and the coal, it does not eliminate the possibility of breakdown of the coal particle into particle sizes permeable to the basket. Indeed, a small amount of fine coal has been found inside the basket. To determine whether fine coal from breakdown of the coal particles is responsible for the conversion, a new basket is being prepared with 0.5{micro}m pore size.

  6. Phase noise performance of analog frequency dividers.

    PubMed

    Driscoll, M M

    1990-01-01

    The phase noise performance obtainable using silicon and GaAs-based TTL (transistor-transistor logic) and ECL (emitter-coupled logic) logic level digital frequency dividers is discussed. Measurement of the spectral performance of two types of analog dividers is reported: a parametric divider using varactor diodes and a regenerative-type divider incorporating a double-balanced mixer in the oscillator feedback circuit. Both dividers were configured for divide-by-two operation at VHF. Evaluation indicates the regenerative divider is capable of providing much lower phase noise than conventional digital logic level devices. The regenerative divider can be successfully operated over bandwidths in excess of an octave, and the design lends itself to small (i.e. TO-8) modular package implementation. Operating frequencies are bounded only by the range of the mixer and RF amplifier utilized and, as such, should extend from HF through microwave.

  7. Electrochemical catalyst recovery method

    DOEpatents

    Silva, Laura J.; Bray, Lane A.

    1995-01-01

    A method of recovering catalyst material from latent catalyst material solids includes: a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications.

  8. Electrochemical catalyst recovery method

    DOEpatents

    Silva, L.J.; Bray, L.A.

    1995-05-30

    A method of recovering catalyst material from latent catalyst material solids includes: (a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; (b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; (c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and (d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications. 3 figs.

  9. Fundamental studies of hydrogen interaction with supported meta and bimetallic catalysts

    SciTech Connect

    Bhatia, Sandeep

    1993-12-07

    The thesis is divided into 3 parts: interaction of H with silica supported Ru catalysts (high pressure in situ NMR), in situ NMR study of H interaction with supported Ru-group IB bimetallic catalysts, and in-situ NMR study of H effects on silica-supported Pt, Rh and Ru catalysts.

  10. Fluidized reduction of oxides on fine metal powders without sintering

    NASA Technical Reports Server (NTRS)

    Hayashi, T.

    1985-01-01

    In the process of reducing extremely fine metal particles (av. particle size or = 1000 angstroms) covered with an oxide layer, the metal particles are fluidized by a gas flow contg. H, heated, and reduced. The method uniformly and easily reduces surface oxide layers of the extremely fine metal particles without causing sintering. The metal particles are useful for magnetic recording materials, conductive paste, powder metallurgy materials, chem. reagents, and catalysts.

  11. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Gas divider. 1065.248 Section 1065.248 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING... testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter...

  12. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Gas divider. 1065.248 Section 1065.248 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING... testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter...

  13. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Gas divider. 1065.248 Section 1065.248 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING... testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter...

  14. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Gas divider. 1065.248 Section 1065.248 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING... testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter...

  15. Power Divider for Waveforms Rich in Harmonics

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III

    2005-01-01

    A method for dividing the power of an electronic signal rich in harmonics involves the use of an improved divider topology. A divider designed with this topology could be used, for example, to propagate a square-wave signal in an amplifier designed with a push-pull configuration to enable the generation of more power than could be generated in another configuration.

  16. Diversity, Disability, and Geographic Digital Divide

    ERIC Educational Resources Information Center

    Sumari, Melati; Carr, Erika; Ndebe-Ngovo, Manjerngie

    2006-01-01

    The phenomenon called digital divide was the focus of this paper. Diversity, disability, and geographical digital divide were relevant to this collaborative project. An extensive review of the literature was conducted for the completion of this project. The evidence for the digital divide in terms of race, level of education, and gender in the…

  17. The Myth about the Digital Divide

    ERIC Educational Resources Information Center

    Hawkins, Brian L.; Oblinge, Diana G.

    2006-01-01

    Although computer ownership is not 100 percent, progress has been made on closing the digital divide. However, defining the digital divide according to the haves and have-nots of computer ownership is only a starting point. Beyond computer ownership, colleges and universities should explore the "second-level digital divide," which can be…

  18. Tech, Teachers & Teens: Bridging the Divide

    ERIC Educational Resources Information Center

    Stuht, Amy Colcord; Colcord, Cean

    2011-01-01

    In past decades, the "digital divide" referred to the gap between those who could afford access to technology and those who could not. The divide has shifted in recent years to reflect the growing technological chasm between teachers and their students: today's schools and teenagers' worlds. The digital divide is widening and deepening…

  19. Long-Life Catalyst

    NASA Technical Reports Server (NTRS)

    1999-01-01

    STC Catalysts, Inc. (SCi) manufactures a noble metal reducible oxide catalyst consisting primarily of platinum and tin dioxide deposited on a ceramic substrate. It is an ambient temperature oxidation catalyst that was developed primarily for Carbon Dioxide Lasers.The catalyst was developed by the NASA Langley Research Center for the Laser Atmospheric Wind Sounder Program (LAWS) which was intended to measure wind velocity on a global basis. There are a number of NASA owned patents covering various aspects of the catalyst.

  20. THE FINE STRUCTURE OF DIPLOCOCCUS PNEUMONIAE

    PubMed Central

    Tomasz, Alexander; Jamieson, James D.; Ottolenghi, Elena

    1964-01-01

    The fine structure of an unencapsulated strain of Diplococcus pneumoniae is described. A striking feature of these bacteria is an intracytoplasmic membrane system which appears to be an extension of septa of dividing bacteria. The possible function of these structures and their relationship to the plasma membrane and other types of intracytoplasmic membranes found in pneumococcus is discussed. PMID:14203390

  1. Fine Arts Evaluation.

    ERIC Educational Resources Information Center

    Nanaimo School District #68 (British Columbia).

    The fine arts as defined by the Ministry of Education (British Columbia) include music, art, and drama with the curriculum focusing on two concepts: creation and appreciation. One of the aims of School District #68 (Nanaimo) is to provide students with the opportunity to gain exposure to, and experience in, fine arts. The Fine Arts Evaluation…

  2. Evaluating Metrics of Drainage Divide Mobility

    NASA Astrophysics Data System (ADS)

    Forte, A. M.; Whipple, K. X.; DiBiase, R.; Gasparini, N. M.; Ouimet, W. B.

    2016-12-01

    Watersheds are the fundamental organizing units in landscapes and thus the controls on drainage divide location and mobility are an essential facet of landscape evolution. Additionally, many common topographic analyses fundamentally assume that river network topology and divide locations are largely static, allowing channel profile form to be interpreted in terms of spatio-temporal patterns of rock uplift rate relative to baselevel, climate, or rock properties. Recently however, it has been suggested that drainage divides are more mobile than previously thought and that divide mobility, and resulting changes in drainage area, can potentially induce changes to fluvial topography comparable to spatio-temporal variation in rock uplift, climate, or rock properties. Ultimately, reliable metrics are needed to diagnose the mobility of divides. One such recently proposed metric is cross-divide contrasts in `chi', a measure of the current topology of the drainage network, but cross-divide contrasts in a number of topographic metrics show promise. Here we use a series of landscape evolution modeling scenarios in which we induce divide mobility under different conditions to test the utility of a suite of plausible topographic metrics of divide mobility and compare these to natural examples. Specifically, we test cross-divide contrasts in mean slope, mean local relief, channel bed elevation at a reference drainage area, and chi. Our results highlight that cross-divide contrasts in chi can only be accurately interpreted in terms of divide mobility when uplift, rock erodibility, climate, and base-level are uniform across both river networks on either side of the divide. This is problematic for application of this metric to natural landscapes as (1) uniformity of all of these parameters is exceedingly unlikely and (2) quantifying the spatial patterns of these parameters is difficult. Consequently, as shown here for both simulated and natural landscapes, simple measures of cross-divide

  3. Fast frequency divider circuit using combinational logic

    DOEpatents

    Helinski, Ryan

    2017-05-30

    The various technologies presented herein relate to performing on-chip frequency division of an operating frequency of a ring oscillator (RO). Per the various embodiments herein, a conflict between RO size versus operational frequency can be addressed by dividing the output frequency of the RO to a frequency that can be measured on-chip. A frequency divider circuit (comprising NOR gates and latches, for example) can be utilized in conjunction with the RO on the chip. In an embodiment, the frequency divider circuit can include a pair of latches coupled to the RO to facilitate dividing the oscillating frequency of the RO by 2. In another embodiment, the frequency divider circuit can include four latches (operating in pairs) coupled to the RO to facilitate dividing the oscillating frequency of the RO by 4. A plurality of ROs can be MUXed to the plurality of ROs by a single oscillation-counting circuit.

  4. Power Divider for Harmonically Rich Waveforms

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III (Inventor)

    2001-01-01

    A power divider divides an RF signal into two output signals having a phase difference of 180 deg. or a multiple thereof. When the RF signal is a square wave or another harmonically rich signal. the phases of the fundamental and the harmonics have the proper relationship. The divider can be implemented in the form of microstrips on a board, with one of the output microstrips having several bends to provide a different electrical length from the other.

  5. Inductive voltage divider modeling in Matlab

    NASA Astrophysics Data System (ADS)

    Andreev, S. A.; Kim, V. L.

    2017-01-01

    Inductive voltage dividers have the most appropriate metrological characteristics on alternative current and are widely used for converting physical signals. The model of a double-decade inductive voltage divider was designed with the help of Matlab/Simulink. The first decade is an inductive voltage divider with balanced winding, the second decade is a single-stage inductive voltage divider. In the paper, a new transfer function algorithm was given. The study shows errors and differences that appeared between the third degree reduced model and a twenty degree unreduced model. The obtained results of amplitude error differ no more than by 7 % between the reduced and unreduced model.

  6. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction

    SciTech Connect

    Song, Chunshan; Schobert, H.H.

    1993-02-01

    Development of new catalysts is a promising approach to more efficient coal liquefaction. It has been recognized that catalysts are superior to supported catalysts for primary liquefaction of coals, because the control of initial coal dissolution or depolymerization requires intimate contact between the catalyst and coal. This research is a fundamental and exploratory study on catalytic coal liquefaction, with the emphasis on the development of novel bimetallic dispersed catalysts for temperature-programmed liquefaction. The ultimate goal of the present research is to develop novel catalytic hydroliquefaction process using highly active dispersed catalysts. The primary objective of this research is to develop novel bimetallic dispersed catalysts from organometallic molecular that can be used in low precursors concentrations (< 1 %) but exhibit high activity for efficient hydroliquefaction of coals under temperature-programmed conditions. The major technical approaches are, first, to prepare the desired heteronuclear organometallic molecules as catalyst precursors that contain covalently bound, two different metal atoms and sulfur in a single molecule. Such precursors will generate finely dispersed bimetallic catalysts such as Fe-Mo, Co-Mo and Ni-Mo binary sulfides upon thermal decomposition. The second major technical approach is to perform the liquefaction of coals unpregnated with the organometallic precursors under temperature-programmed conditions, where the programmed heat-up serves as a step for both catalyst activation and coal pretreatment or preconversion. Two to three different complexes for each of the Fe-Mo, Co-Mo, and Ni-Mo combinations will be prepared. Initial catalyst screening tests will be conducted using a subbituminous coal and a bituminous coal. Effects of coal rank and solvents will be examined with the selected bimetallic catalysts which showed much higher activity than the dispersed catalysts from conventional precursors.

  7. Pt-Ni and Pt-Co Catalyst Synthesis Route for Fuel Cell Applications

    NASA Technical Reports Server (NTRS)

    Firdosy, Samad A.; Ravi, Vilupanur A.; Valdez, Thomas I.; Kisor, Adam; Narayan, Sri R.

    2013-01-01

    Oxygen reduction reactions (ORRs) at the cathode are the rate-limiting step in fuel cell performance. The ORR is 100 times slower than the corresponding hydrogen oxidation at the anode. Speeding up the reaction at the cathode will improve fuel cell efficiency. The cathode material is generally Pt powder painted onto a substrate (e.g., graphite paper). Recent efforts in the fuel cell area have focused on replacing Pt with Pt-X alloys (where X = Co, Ni, Zr, etc.) in order to (a) reduce cost, and (b) increase ORR rates. One of these strategies is to increase ORR rates by reducing the powder size, which would result in an increase in the surface area, thereby facilitating faster reaction rates. In this work, a process has been developed that creates Pt-Ni or Pt-Co alloys that are finely divided (on the nano scale) and provide equivalent performance at lower Pt loadings. Lower Pt loadings will translate to lower cost. Precursor salts of the metals are dissolved in water and mixed. Next, the salt mixtures are dried on a hot plate. Finally, the dried salt mixture is heattreated in a furnace under flowing reducing gas. The catalyst powder is then used to fabricate a membrane electrode assembly (MEA) for electrochemical performance testing. The Pt- Co catalyst-based MEA showed comparable performance to an MEA fabri cated using a standard Pt black fuel cell catalyst. The main objective of this program has been to increase the overall efficiencies of fuel cell systems to support power for manned lunar bases. This work may also have an impact on terrestrial programs, possibly to support the effort to develop a carbon-free energy source. This catalyst can be used to fabricate high-efficiency fuel cell units that can be used in space as regenerative fuel cell systems, and terrestrially as primary fuel cells. Terrestrially, this technology will become increasingly important when transition to a hydrogen economy occurs.

  8. Lewis Base Catalysts 6: Carbene Catalysts

    PubMed Central

    Moore, Jennifer L.

    2013-01-01

    The use of N-heterocyclic carbenes as catalysts for organic transformations has received increased attention in the past 10 years. A discussion of catalyst development and nucleophilic characteristics precedes a description of recent advancements and new reactions using N-heterocyclic carbenes in catalysis. PMID:21494949

  9. Nano-catalysts: Key to the Greener Pathways Leading to Sustainability

    EPA Science Inventory

    Synthetic processes using alternative energy input in combination with nano-catalysts shorten the reaction time that eliminate or minimize side product formation. This concept is already finding acceptance in the syntheses of pharmaceuticals, fine chemicals, and polymers and may ...

  10. Nano-catalysts: Key to the Greener Pathways Leading to Sustainability

    EPA Science Inventory

    Synthetic processes using alternative energy input in combination with nano-catalysts shorten the reaction time that eliminate or minimize side product formation. This concept is already finding acceptance in the syntheses of pharmaceuticals, fine chemicals, and polymers and may ...

  11. Deactivation of Oxidation Catalysts

    DTIC Science & Technology

    1991-05-01

    the fresh catalyst . The loss in chromium may be related to the formation of volatile chromium oxychlorde which vaporizes from the catalyst . It is...CeO2 only marginally improved the thtrmal stability. The addition of 2% water vapor inhibited the oxidation of ethanol for all three copper catalysts ...original activity. Field tests of a copper chromite catalyst on process gas containing H2S, methyl mercaptan, n-aldehydes, and furfural showed

  12. Parochial Geographies: Growing up in Divided Belfast

    ERIC Educational Resources Information Center

    Leonard, Madeleine

    2010-01-01

    This article explores the ways in which teenagers occupy and manage space in one divided community in Northern Ireland. Drawing on stories, maps and focus group discussions with 80 teenagers, from an interface area in Belfast, the article reveals their perceptions and experiences of divided cities, as risky landscapes. Teenagers respond to these…

  13. PIONEER POLAR STRUCTURES, JAMESWAY BUILDING DIVIDER

    DTIC Science & Technology

    A building divider was developed for the Jamesway polar shelter to separate two facilities located in the same building. The divider is constructed...near McMurdo, Antarctica. It was concluded that it satisfies the requirements for separating spaces in a Jamesway and should be used as a standard accessory for the Jamesway .

  14. Social Welfare Implications of the Digital Divide

    ERIC Educational Resources Information Center

    Kim, Eunjin; Lee, Byungtae; Menon, Nirup M.

    2009-01-01

    The Internet plays a critical role in informing individuals about society, politics, business, and the environment. So much so that it has been said that the digital divide makes the segment of society on the ''right side'' of the divide (the digitally endowed group) better off and that on the ''wrong side'' (the digitally challenged group) worse…

  15. Bridge the Digital Divide for Educational Equity

    ERIC Educational Resources Information Center

    Mason, Christine Y.; Dodds, Richard

    2005-01-01

    Students' technological savvy has challenged schools to make greater use of computers and the Internet in their curricula, but unfortunately, not every student has the same access to it, and the inability to keep pace has created a digital divide that continues to widen. The digital divide particularly affects students who are black, Hispanic,…

  16. Attrition Resistant Fischer-Tropsch Catalysts Based on FCC Supports

    SciTech Connect

    Adeyiga, Adeyinka

    2010-02-05

    Commercial spent fluid catalytic cracking (FCC) catalysts provided by Engelhard and Albemarle were used as supports for Fe-based catalysts with the goal of improving the attrition resistance of typical F-T catalysts. Catalysts with the Ruhrchemie composition (100 Fe/5 Cu/4.2 K/25 spent FCC on mass basis) were prepared by wet impregnation. XRD and XANES analysis showed the presence of Fe{sub 2}O{sub 3} in calcined catalysts. FeC{sub x} and Fe{sub 3}O{sub 4} were present in the activated catalysts. The metal composition of the catalysts was analyzed by ICP-MS. F-T activity of the catalysts activated in situ in CO at the same conditions as used prior to the attrition tests was measured using a fixed bed reactor at T = 573 K, P = 1.38 MPa and H{sub 2}:CO ratio of 0.67. Cu and K promoted Fe supported over Engelhard provided spent FCC catalyst shows relatively good attrition resistance (8.2 wt% fines lost), high CO conversion (81%) and C{sub 5}+ hydrocarbons selectivity (18.3%).

  17. Catalyst by Design

    SciTech Connect

    Narula, Chaitanya Kumar; DeBusk, Melanie Moses

    2014-01-01

    The development of new catalytic materials is still dominated by trial and error methods. Although it has been successful, the empirical development of catalytic materials is time consuming and expensive with no guarantee of success. In our laboratories, we are developing a comprehensive catalysts by design that involves state-of-the-art first principle density functional theory calculations, experimental design of catalyst sites, and sub- ngstr m resolution imaging with an aberration-corrected electron microscope to characterize the microstructure. In this chapter, we focus on supported platinum cluster catalyst systems which are one of the most important industrial catalysts and attempt to demonstrate the feasibility of the catalyst by design concept.

  18. Characterization of three-way automotive catalysts

    SciTech Connect

    Kenik, E.A.; More, K.L.; LaBarge, W.

    1997-04-01

    The CRADA between Delphi Automotive Systems (Delphi; formerly General Motors - AC Delco, Systems) and Lockheed Martin Energy Research (LMER) on automotive catalysts was completed at the end of FY96, after a ten month, no-cost extension. The CRADA was aimed at improved performance and lifetime of noble metal based three-way-catalysts (TWC), which are the primary catalytic system for automotive emission control systems. While these TWC can meet the currently required emission standards, higher than optimum noble metal loadings are often required to meet lifetime requirements. In addition, more stringent emission standards will be imposed in the near future, demanding improved performance and service life from these catalysts. Understanding the changes of TWC conversion efficiency with ageing is a critical need in improving these catalysts. Initially in a fresh catalyst, the active material is often distributed on a very fine scale, approaching single atoms or small atomic clusters. As such, a wide range of analytical techniques have been employed to provide high spatial resolution characterization of the evolving state of the catalytic material.

  19. System for reactivating catalysts

    SciTech Connect

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2010-03-02

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  20. Catalytic conversion of lignocellulosic biomass to fine chemicals and fuels.

    PubMed

    Zhou, Chun-Hui; Xia, Xi; Lin, Chun-Xiang; Tong, Dong-Shen; Beltramini, Jorge

    2011-11-01

    Lignocellulosic biomass is the most abundant and bio-renewable resource with great potential for sustainable production of chemicals and fuels. This critical review provides insights into the state-of the-art accomplishments in the chemocatalytic technologies to generate fuels and value-added chemicals from lignocellulosic biomass, with an emphasis on its major component, cellulose. Catalytic hydrolysis, solvolysis, liquefaction, pyrolysis, gasification, hydrogenolysis and hydrogenation are the major processes presently studied. Regarding catalytic hydrolysis, the acid catalysts cover inorganic or organic acids and various solid acids such as sulfonated carbon, zeolites, heteropolyacids and oxides. Liquefaction and fast pyrolysis of cellulose are primarily conducted over catalysts with proper acidity/basicity. Gasification is typically conducted over supported noble metal catalysts. Reaction conditions, solvents and catalysts are the prime factors that affect the yield and composition of the target products. Most of processes yield a complex mixture, leading to problematic upgrading and separation. An emerging technique is to integrate hydrolysis, liquefaction or pyrolysis with hydrogenation over multifunctional solid catalysts to convert lignocellulosic biomass to value-added fine chemicals and bio-hydrocarbon fuels. And the promising catalysts might be supported transition metal catalysts and zeolite-related materials. There still exist technological barriers that need to be overcome (229 references). This journal is © The Royal Society of Chemistry 2011

  1. Magnetic-Flux-Compensated Voltage Divider

    NASA Technical Reports Server (NTRS)

    Mata, Carlos T.

    2005-01-01

    A magnetic-flux-compensated voltage-divider circuit has been proposed for use in measuring the true potential across a component that is exposed to large, rapidly varying electric currents like those produced by lightning strikes. An example of such a component is a lightning arrester, which is typically exposed to currents of the order of tens of kiloamperes, having rise times of the order of hundreds of nanoseconds. Traditional voltage-divider circuits are not designed for magnetic-flux-compensation: They contain uncompensated loops having areas large enough that the transient magnetic fluxes associated with large transient currents induce spurious voltages large enough to distort voltage-divider outputs significantly. A drawing of the proposed circuit was not available at the time of receipt of information for this article. What is known from a summary textual description is that the proposed circuit would contain a total of four voltage dividers: There would be two mixed dividers in parallel with each other and with the component of interest (e.g., a lightning arrester), plus two mixed dividers in parallel with each other and in series with the component of interest in the same plane. The electrical and geometric configuration would provide compensation for induced voltages, including those attributable to asymmetry in the volumetric density of the lightning or other transient current, canceling out the spurious voltages and measuring the true voltage across the component.

  2. Catalyst patterning for nanowire devices

    NASA Technical Reports Server (NTRS)

    Li, Jun (Inventor); Cassell, Alan M. (Inventor); Han, Jie (Inventor)

    2004-01-01

    Nanowire devices may be provided that are based on carbon nanotubes or single-crystal semiconductor nanowires. The nanowire devices may be formed on a substrate. Catalyst sites may be formed on the substrate. The catalyst sites may be formed using lithography, thin metal layers that form individual catalyst sites when heated, collapsible porous catalyst-filled microscopic spheres, microscopic spheres that serve as masks for catalyst deposition, electrochemical deposition techniques, and catalyst inks. Nanowires may be grown from the catalyst sites.

  3. Mississippi Fine Arts Framework.

    ERIC Educational Resources Information Center

    Mississippi State Dept. of Education, Jackson.

    The Mississippi Fine Arts Framework is designed to develop K-12 students' interest and expertise in dance, music, theater arts, and visual arts. The introductory fine arts course, for secondary level students, explores the relationship and the function of the arts in both historical and contemporary culture through creative projects, performance,…

  4. Textured catalysts and methods of making textured catalysts

    DOEpatents

    Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.

    2007-03-06

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  5. Temporal dynamics of divided spatial attention.

    PubMed

    Itthipuripat, Sirawaj; Garcia, Javier O; Serences, John T

    2013-05-01

    In naturalistic settings, observers often have to monitor multiple objects dispersed throughout the visual scene. However, the degree to which spatial attention can be divided across spatially noncontiguous objects has long been debated, particularly when those objects are in close proximity. Moreover, the temporal dynamics of divided attention are unclear: is the process of dividing spatial attention gradual and continuous, or does it onset in a discrete manner? To address these issues, we recorded steady-state visual evoked potentials (SSVEPs) as subjects covertly monitored two flickering targets while ignoring an intervening distractor that flickered at a different frequency. All three stimuli were clustered within either the lower left or the lower right quadrant, and our dependent measure was SSVEP power at the target and distractor frequencies measured over time. In two experiments, we observed a temporally discrete increase in power for target- vs. distractor-evoked SSVEPs extending from ∼350 to 150 ms prior to correct (but not incorrect) responses. The divergence in SSVEP power immediately prior to a correct response suggests that spatial attention can be divided across noncontiguous locations, even when the targets are closely spaced within a single quadrant. In addition, the division of spatial attention appears to be relatively discrete, as opposed to slow and continuous. Finally, the predictive relationship between SSVEP power and behavior demonstrates that these neurophysiological measures of divided attention are meaningfully related to cognitive function.

  6. Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

    PubMed Central

    Bagheri, Samira; Muhd Julkapli, Nurhidayatullaili; Bee Abd Hamid, Sharifah

    2014-01-01

    The lack of stability is a challenge for most heterogeneous catalysts. During operations, the agglomeration of particles may block the active sites of the catalyst, which is believed to contribute to its instability. Recently, titanium oxide (TiO2) was introduced as an alternative support material for heterogeneous catalyst due to the effect of its high surface area stabilizing the catalysts in its mesoporous structure. TiO2 supported metal catalysts have attracted interest due to TiO2 nanoparticles high activity for various reduction and oxidation reactions at low pressures and temperatures. Furthermore, TiO2 was found to be a good metal oxide catalyst support due to the strong metal support interaction, chemical stability, and acid-base property. The aforementioned properties make heterogeneous TiO2 supported catalysts show a high potential in photocatalyst-related applications, electrodes for wet solar cells, synthesis of fine chemicals, and others. This review focuses on TiO2 as a support material for heterogeneous catalysts and its potential applications. PMID:25383380

  7. Titanium dioxide as a catalyst support in heterogeneous catalysis.

    PubMed

    Bagheri, Samira; Muhd Julkapli, Nurhidayatullaili; Bee Abd Hamid, Sharifah

    2014-01-01

    The lack of stability is a challenge for most heterogeneous catalysts. During operations, the agglomeration of particles may block the active sites of the catalyst, which is believed to contribute to its instability. Recently, titanium oxide (TiO2) was introduced as an alternative support material for heterogeneous catalyst due to the effect of its high surface area stabilizing the catalysts in its mesoporous structure. TiO2 supported metal catalysts have attracted interest due to TiO2 nanoparticles high activity for various reduction and oxidation reactions at low pressures and temperatures. Furthermore, TiO2 was found to be a good metal oxide catalyst support due to the strong metal support interaction, chemical stability, and acid-base property. The aforementioned properties make heterogeneous TiO2 supported catalysts show a high potential in photocatalyst-related applications, electrodes for wet solar cells, synthesis of fine chemicals, and others. This review focuses on TiO2 as a support material for heterogeneous catalysts and its potential applications.

  8. Methods of making textured catalysts

    DOEpatents

    Werpy, Todd [West Richland, WA; Frye, Jr., John G.; Wang, Yong [Richland, WA; Zacher, Alan H [Kennewick, WA

    2010-08-17

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  9. Catalyst Alloys Processing

    NASA Astrophysics Data System (ADS)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  10. Analogue Divider by Averaging a Triangular Wave

    NASA Astrophysics Data System (ADS)

    Selvam, Krishnagiri Chinnathambi

    2017-03-01

    A new analogue divider circuit by averaging a triangular wave using operational amplifiers is explained in this paper. The triangle wave averaging analog divider using operational amplifiers is explained here. The reference triangular waveform is shifted from zero voltage level up towards positive power supply voltage level. Its positive portion is obtained by a positive rectifier and its average value is obtained by a low pass filter. The same triangular waveform is shifted from zero voltage level to down towards negative power supply voltage level. Its negative portion is obtained by a negative rectifier and its average value is obtained by another low pass filter. Both the averaged voltages are combined in a summing amplifier and the summed voltage is given to an op-amp as negative input. This op-amp is configured to work in a negative closed environment. The op-amp output is the divider output.

  11. Analogue Divider by Averaging a Triangular Wave

    NASA Astrophysics Data System (ADS)

    Selvam, Krishnagiri Chinnathambi

    2017-08-01

    A new analogue divider circuit by averaging a triangular wave using operational amplifiers is explained in this paper. The triangle wave averaging analog divider using operational amplifiers is explained here. The reference triangular waveform is shifted from zero voltage level up towards positive power supply voltage level. Its positive portion is obtained by a positive rectifier and its average value is obtained by a low pass filter. The same triangular waveform is shifted from zero voltage level to down towards negative power supply voltage level. Its negative portion is obtained by a negative rectifier and its average value is obtained by another low pass filter. Both the averaged voltages are combined in a summing amplifier and the summed voltage is given to an op-amp as negative input. This op-amp is configured to work in a negative closed environment. The op-amp output is the divider output.

  12. Wideband unbalanced waveguide power dividers and combiners

    DOEpatents

    Halligan, Matthew; McDonald, Jacob Jeremiah; Strassner, II, Bernd H.

    2016-05-17

    The various technologies presented herein relate to waveguide dividers and waveguide combiners for application in radar systems, wireless communications, etc. Waveguide dividers-combiners can be manufactured in accordance with custom dimensions, as well as in accordance with waveguide standards such that the input and output ports are of a defined dimension and have a common impedance. Various embodiments are presented which can incorporate one or more septum(s), one or more pairs of septums, an iris, an input matching region, a notch located on the input waveguide arm, waveguide arms having stepped transformer regions, etc. The various divider configurations presented herein can be utilized in high fractional bandwidth applications, e.g., a fractional bandwidth of about 30%, and RF applications in the Ka frequency band (e.g., 26.5-40 GHz).

  13. WIDE BAND REGENERATIVE FREQUENCY DIVIDER AND MULTIPLIER

    DOEpatents

    Laine, E.F.

    1959-11-17

    A regenerative frequency divider and multiplier having wide band input characteristics is presented. The circuit produces output oscillations having frequencies related by a fixed ratio to input oscillations over a wide band of frequencies. In accomplishing this end, the divider-multiplier includes a wide band input circuit coupled by mixer means to a wide band output circuit having a pass band related by a fixed ratio to that of the input circuit. A regenerative feedback circuit derives a fixed frequency ratio feedback signal from the output circuit and applies same to the mixer means in proper phase relation to sustain fixed frequency ratio oscillations in the output circuit.

  14. Development of precipitated iron Fischer-Tropsch catalysts. Quarterly technical progress report, 1 January 1996--31 March 1996

    SciTech Connect

    Bukur, D.B.

    1996-06-03

    The overall contract objectives are to: (1) demonstrate repeatability of performance and preparation procedure of two high activity, high alpha iron Fischer-Tropsch catalysts synthesized at Texas A&M University (TAMU); (2) seek potential improvements in the catalyst performance through variations in process conditions, pretreatment procedures and/or modifications in catalyst synthesis; (3) investigate performance of catalysts in a small scale bubble column slurry reactor, and (4) investigate feasibility of producing catalysts on a large scale in collaboration with a catalyst manufacturer. In order to achieve these objectives the work is divided into ten tasks, which are described and their accomplishments are reported.

  15. Polyolefin catalyst manufacturing

    SciTech Connect

    Inkrott, K.E.; Scinta, J.; Smith, P.D. )

    1989-10-16

    Statistical process control (SPC) procedures are absolutely essential for making new-generation polyolefin catalysts with the consistent high quality required by modern polyolefin processes. Stringent quality assurance is critical to the production of today's high-performance catalysts. Research and development efforts during the last 20 years have led to major technological improvements in the polyolefin industry. New generation catalysts, which once were laboratory curiosities, must now be produced commercially on a regular and consistent basis to meet the increasing requirements of the plastics manufacturing industry. To illustrate the more stringent requirements for producing the new generation polyolefin catalysts, the authors compare the relatively simple, first-generation polypropylene catalyst production requirements with some of the basic requirements of manufacturing a more complex new-generation catalyst, such as Catalyst Resources Inc.'s LYNX 900. The principles which hold true for the new-generation catalysts such as LYNX 900 are shown to apply equally to the scale-up of other advanced technology polyolefin catalysts.

  16. Liquefaction with microencapsulated catalysts

    DOEpatents

    Weller, Sol W.

    1985-01-01

    A method of dispersing a liquefaction catalyst within coal or other carbonaceous solids involves providing a suspension in oil of microcapsules containing the catalyst. An aqueous solution of a catalytic metal salt is emulsified in the water-immiscible oil and the resulting minute droplets microencapsulated in polymeric shells by interfacial polycondensation. The catalyst is subsequently blended and dispersed throughout the powdered carbonaceous material to be liquefied. At liquefaction temperatures the polymeric microcapsules are destroyed and the catalyst converted to minute crystallites in intimate contact with the carbonaceous material.

  17. Fine motor control

    MedlinePlus

    ... with Parkinson disease have trouble speaking, eating, and writing because they have lost fine motor control. The ... Drawing lines or circles Folding clothes Holding and writing with a pencil Stacking blocks Zipping a zipper

  18. Analyses of fine paste ceramics

    SciTech Connect

    Sabloff, J A

    1980-01-01

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics. (DLC)

  19. THE DEVELOPMENT OF THE TEACHING SPACE DIVIDER.

    ERIC Educational Resources Information Center

    BELLOMY, CLEON C.; CAUDILL, WILLIAM W.

    TYPES OF VERTICAL WORK SURFACES AND THE DEVELOPMENT OF A MODEL TEACHING SPACE DIVIDER ARE DISCUSSED IN THIS REPORT. THIS DESIGN IS BASED ON THE EXPRESSED NEED FOR MORE TACKBOARD AND SHELVING SPACE, AND FOR MOVABLE PARTITIONS. THE MODEL PANELS WHICH SERVE DIRECTLY AS PARTITIONS RATHER THAN BEING OVERLAID ON A PLASTERED SURFACE, INCLUDE THE…

  20. Crossing Divides: The Legacy of Graham Nuthall

    ERIC Educational Resources Information Center

    Davis, Alan

    2006-01-01

    Graham Nuthall's work cuts across methodological and conceptual divides that have worked against the development of a theory of learning and teaching that is at once predictive and practical. The micro-genetic approach to research on learning in classrooms that he developed with Adrienne Alton-Lee successfully transcends the unhelpful dichotomy…

  1. A Nation Divided on Education in 2003

    ERIC Educational Resources Information Center

    Hardy, Lawrence

    2004-01-01

    To understand what is going on in American education, it might help to turn to a relatively neutral source, the Pew Research Center for the People and the Press, and its released report, The 2004 Political Landscape: Evenly Divided and Increasingly Polarized. "Over the past four years, the American electorate has been dealt a series of body…

  2. From Digital Divide to Digital Democracy.

    ERIC Educational Resources Information Center

    de los Santos, Gerardo E., Ed.; de los Santos, Alfredo G., Jr., Ed.; Milliron, Mark David, Ed.

    This publication is one of many efforts of the League for Innovation in the Community College to address the issue of societal technology access and learning needs. This work addresses the issue of the digital divide, which includes the often conflicting perspectives of information technology (IT) access and literacy needs held by government…

  3. Project DIVIDE Instrument Development. Technical Report # 0810

    ERIC Educational Resources Information Center

    Ketterlin-Geller, Leanne; Jung, Eunju; Geller, Josh; Yovanoff, Paul

    2008-01-01

    In this technical report, we describe the development of cognitive diagnostic test items that form the basis of the diagnostic system for Project DIVIDE (Dynamic Instruction Via Individually Designed Environments). The construct underlying the diagnostic test is division of fractions. We include a description of the process we used to identify the…

  4. The electronic health record: a digital divide?

    PubMed

    Glaser, John

    2007-10-01

    The gap between EHR adoption among larger providers versus adoption by smaller or rural providers has caused a "digital divide" that could threaten smaller providers' survival in the years ahead. Closing this gap will require the collective action of providers, payers, and government.

  5. Young People's Internet Use: Divided or Diversified?

    ERIC Educational Resources Information Center

    Boonaert, Tom; Vettenburg, Nicole

    2011-01-01

    This article critically analyses research on young people's internet use. Based on a literature analysis, it examines which young people do what on the internet. These results invite a reflection on the dominant discourse on the digital divide. Within this discourse, there is a strong focus on the use of the internet for information purposes only,…

  6. Hydroxide catalysts for lignin depolymerization

    DOEpatents

    Beckham, Gregg T.; Biddy, Mary J.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-04-25

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  7. Controlling the inhomogeneity of solid catalysts at the mesoscopic scale

    NASA Astrophysics Data System (ADS)

    Huang, Hua; Wada, Takahiro; Ariga, Hiroko; Takakusagi, Satoru; Asakura, Kiyotaka; Iwasawa, Yasuhiro

    2017-09-01

    High-performance catalysts are often composed of two or more active phases, which are believed to interact with each other at the mesoscopic scale structure. Unlike conventional powder catalysts flat surfaces is advantageous in that its surface structure can be precisely designed. We prepared precisely designed Sb2O4/VSbO4/Si catalysts containing Sb2O4 ribbons with finely controlled width and separation by electron lithography. We demonstrated that the acrolein generation rate on the catalysts was related to the width and separation of the Sb2O4 ribbons. This work shows the possibility to regulate catalyses by inhomogeneity of the surface structure at the mesoscopic level.

  8. Cathodic catalysts in bioelectrochemical systems for energy recovery from wastewater.

    PubMed

    Liu, Xian-Wei; Li, Wen-Wei; Yu, Han-Qing

    2014-11-21

    Bioelectrochemical systems (BESs), in which microorganisms are utilized as a self-regenerable catalyst at the anode of an electrochemical cell to directly extract electrical energy from organic matter, have been widely recognized as a promising technology for energy-efficient wastewater treatment or even for net energy generation. However, currently BES performance is constrained by poor cathode reaction kinetics. Thus, there is a strong impetus to improve the cathodic catalysis performance through proper selection and design of catalysts. This review introduces the fundamentals and current development status of various cathodic catalysts (including electrocatalysts, photoelectrocatalysts and bioelectrocatalysts) in BES, identifies their limitations and influential factors, compares their catalytic performances in terms of catalytic efficiency, stability, selectivity, etc., and discusses the possible optimization strategies and future research directions. Special focus is given on the analysis of how the catalytic performance of different catalysts can be improved by fine tuning their physicochemical or physiological properties.

  9. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2012-10-02

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  10. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2015-09-29

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  11. Reducible oxide based catalysts

    DOEpatents

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  12. Fischer-Tropsch Catalysts

    NASA Technical Reports Server (NTRS)

    White, James H. (Inventor); Taylor, Jesse W. (Inventor)

    2008-01-01

    Catalyst compositions and methods for F-T synthesis which exhibit high CO conversion with minor levels (preferably less than 35% and more preferably less than 5%) or no measurable carbon dioxide generation. F-T active catalysts are prepared by reduction of certain oxygen deficient mixed metal oxides.

  13. Organometallic polymerization catalysts

    SciTech Connect

    Waymouth, R.M.

    1993-12-31

    Well-defined transition metal catalysts have resulted in exciting new opportunities in polymer synthesis. The stereochemistry of vinyl polymers can be rationally controlled with choice of the appropriate catalysts. Studies with optically active catalyst precursors have revealed considerable information on the absolute stereochemistry of olefin polymerization and have led to the synthesis of novel chiral polyolefins. The development of homogeneous olefin metathesis catalysts has also led to a variety of well-defined new polymer structures with controlled molecular weight and molecular weight distribution. Recent advances in understanding the mechanisms and stereochemistry of homogeneous transition metal catalyzed polymerization will be discussed. The ability to control polymer structure through catalyst design presents exciting opportunities in the synthesis of {open_quotes}tailor-made{close_quotes} macromolecules.

  14. The Digital Divide: A Global View

    NASA Astrophysics Data System (ADS)

    Ntoko, Alexander

    2011-04-01

    Huge progress was made in bridging the digital divide in first decade of 21^st century. This was largely due to the explosive growth of mobile, which saw numbers rise from under 500 million to over five billion mobile cellular subscriptions in just ten years. With household mobile penetration rates of over 50% even in rural areas of developing countries, we have achieved the dream of bringing all the world's people within reach of communications technology. We must now, however, replicate the mobile miracle for the Internet, and especially broadband, if we are to avoid creating a new broadband breach to replace the digital divide. Three things need to happen for this to be achieved: firstly, broadband needs to be brought to the top of the development agenda; secondly, broadband needs to become much more affordable and thirdly, security needs to be part of the strategy.

  15. Low phase noise digital frequency divider

    NASA Technical Reports Server (NTRS)

    Lutes, G. F., Jr. (Inventor)

    1973-01-01

    A low phase noise frequency divider composed of a grating arrangement is disclosed. The grating arrangement supplies selected portions of an input reference signal to be divided to a tuned circuit without any phase noise due to the grating action. The arrangement which in one embodiment consists of an FET is connected to the tuned circuit input to short out the input except when the input reference signal amplitude crosses ground level in a positive direction and a gate enabling signal is present at the gate electrode of the FET. The gate enabling signal alone does not decouple the tuned circuit input from ground, therefore phase noise, due to the leading and trailing edges of each gate-enabling signal, is substantially eliminated.

  16. Divided or kissing nevus of the penis.

    PubMed

    Hardin, Carolyn A; Tieu, Kathy D

    2013-10-16

    The divided or kissing nevus is an unusual congenital melanocytic nevus. By definition, these nevi appear on skin that separates during embryological development. These lesions have been reported on the eyelids, fingers, and rarely the penis. We describe an 18 year old uncircumcised male who presented with an asymptomatic darkly pigmented patch on the glans penis. He reported that the lesion had appeared recently and was enlarging. Physical examination revealed a second symmetric lesion on the adjacent foreskin. Punch biopsy of the lesion on the glans penis showed abundant intradermal melanocytes devoid of mitoses and atypia, consistent with an intradermal melanocytic nevus. Based on the benign histologic nature and clinical exam, the lesion was diagnosed as a divided or kissing nevus of the penis. Proposed treatments include excision and grafting as well as Nd:YAG laser therapy. However, these patients may be safely monitored with regular follow-up skin examinations because there is minimal risk of malignant transformation.

  17. Can Attention be Divided Between Perceptual Groups?

    NASA Technical Reports Server (NTRS)

    McCann, Robert S.; Foyle, David C.; Johnston, James C.; Hart, Sandra G. (Technical Monitor)

    1994-01-01

    Previous work using Head-Up Displays (HUDs) suggests that the visual system parses the HUD and the outside world into distinct perceptual groups, with attention deployed sequentially to first one group and then the other. New experiments show that both groups can be processed in parallel in a divided attention search task, even though subjects have just processed a stimulus in one perceptual group or the other. Implications for models of visual attention will be discussed.

  18. Can Attention be Divided Between Perceptual Groups?

    NASA Technical Reports Server (NTRS)

    McCann, Robert S.; Foyle, David C.; Johnston, James C.; Hart, Sandra G. (Technical Monitor)

    1994-01-01

    Previous work using Head-Up Displays (HUDs) suggests that the visual system parses the HUD and the outside world into distinct perceptual groups, with attention deployed sequentially to first one group and then the other. New experiments show that both groups can be processed in parallel in a divided attention search task, even though subjects have just processed a stimulus in one perceptual group or the other. Implications for models of visual attention will be discussed.

  19. Lake Buchannan, Great Dividing Range, Queensland, Australia

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Lake Buchannan, a small but blue and prominent in the center of the view, lies in the Great Dividing of Queensland, Australia (22.0S, 146.0E). The mountain range in this case is a low plateau of no more than 2,000 to 3,000 ft altitude. The interior is dry, mostly in pasture but the coastal zone in contrast, is wet tropical country where bananas and sugarcane are grown.

  20. Will the Nicaragua Canal connect or divide?

    PubMed

    Gross, Michael

    2014-11-03

    A century after the opening of the Panama Canal, a second inter-oceanic passage is set to be built in Central America, this time in Nicaragua. The ambitious and astronomically expensive project promises to bring economic opportunity to a poor country but it also carries risks to its tropical ecosystems. Will the new waterway ultimately link two oceans or divide a continent? Michael Gross investigates.

  1. Self-organization of divided hierarchy

    NASA Astrophysics Data System (ADS)

    Odagaki, Takashi; Kitada, Keigo; Omizo, Kenta; Fujie, Ryo

    2015-03-01

    There are two types of extreme form of hierarchy, one is the plutonomy where small fraction of winners and losers and many people in the middle class appear and the other a divided hierarchy where half of population become winners and the remaining half become losers. We study the emergence of the divided hierarchy in a model society which consists of bellicose individuals who always try to fight and fight with the strongest neighbor and pacific individuals who always try not to fight and when necessary fight with the weakest neighbor. In our model society, (1) individuals make random walk on a square lattice, (2) when two individuals encounter they fight each other and (3) the winner deprives wealth from the loser. By a Monte Carlo simulation, we show that there are two transitions when the population density is increased; one is a transition from the egalitarian society to a hierarchical society I where winners, losers and middle classes coexist and the other is a transition from the hierarchical society I to a hierarchical society II where winners and losers exist but no middle classes exist, that is the divided hierarchy. We also show that clusters consisting mostly of bellicose individuals appear in the hierarchical society I.

  2. Splicing the Divide: A Review of Research on the Evolving Digital Divide among K-12 Students

    ERIC Educational Resources Information Center

    Dolan, Jennifer E.

    2016-01-01

    The digital divide has narrowed with regard to one definition of access to technology--the binary view of the "haves" and "have-nots." However, use of technology at home and in school is not equitable for all students. According to recent literature, a broader and more nuanced definition of the technological divide is necessary…

  3. Splicing the Divide: A Review of Research on the Evolving Digital Divide among K-12 Students

    ERIC Educational Resources Information Center

    Dolan, Jennifer E.

    2016-01-01

    The digital divide has narrowed with regard to one definition of access to technology--the binary view of the "haves" and "have-nots." However, use of technology at home and in school is not equitable for all students. According to recent literature, a broader and more nuanced definition of the technological divide is necessary…

  4. ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

    SciTech Connect

    K. Jothimurugesan; James G. Goodwin, Jr.; Santosh K. Gangwal

    1999-10-01

    Fischer-Tropsch (FT) synthesis to convert syngas (CO + H{sub 2}) derived from natural gas or coal to liquid fuels and wax is a well-established technology. For low H{sub 2} to CO ratio syngas produced from CO{sub 2} reforming of natural gas or from gasification of coal, the use of Fe catalysts is attractive because of their high water gas shift activity in addition to their high FT activity. Fe catalysts are also attractive due to their low cost and low methane selectivity. Because of the highly exothermic nature of the FT reaction, there has been a recent move away from fixed-bed reactors toward the development of slurry bubble column reactors (SBCRs) that employ 30 to 90 {micro}m catalyst particles suspended in a waxy liquid for efficient heat removal. However, the use of FeFT catalysts in an SBCR has been problematic due to severe catalyst attrition resulting in fines that plug the filter employed to separate the catalyst from the waxy product. Fe catalysts can undergo attrition in SBCRs not only due to vigorous movement and collisions but also due to phase changes that occur during activation and reaction.

  5. Catalytic upgrading of butyric acid towards fine chemicals and biofuels

    PubMed Central

    Sjöblom, Magnus; Matsakas, Leonidas; Christakopoulos, Paul; Rova, Ulrika

    2016-01-01

    Fermentation-based production of butyric acid is robust and efficient. Modern catalytic technologies make it possible to convert butyric acid to important fine chemicals and biofuels. Here, current chemocatalytic and biocatalytic conversion methods are reviewed with a focus on upgrading butyric acid to 1-butanol or butyl-butyrate. Supported Ruthenium- and Platinum-based catalyst and lipase exhibit important activities which can pave the way for more sustainable process concepts for the production of green fuels and chemicals. PMID:26994015

  6. America's digital divide: 2000-2003 trends.

    PubMed

    Whaley, Kermit C

    2004-04-01

    Computer ownership and literacy, along with Internet access and its many applications, has become, for many, a trademark for the Americans' lifestyle. Research shows that computer ownership and literacy, along with Internet access and expertise, is rapidly changing how Americans go about their business. The technological industry is providing many opportunities for Americans to operate in markets, global and local, not previously available. These changes are apparent across all U.S. sociocultural and geographic boundaries. Yet, upon close analysis, there are individuals and communities less connected with many completely excluded from participation. Those individuals exist below a line called the Digital Divide. Growth in computer ownership and Internet use, while offering optimism that the Digital Divide is narrowing, also illustrates that, without focused intervention will for certain populations, continue. Public and private programs, focus groups, and pocks of community activism, each hope to correct the disparities among on- and-off line Americans. On many fronts, there is evidence that progress is being made by many. Income, race, age, and geographic location are often the determining factors.

  7. Catalyst for microelectromechanical systems microreactors

    DOEpatents

    Morse, Jeffrey D [Martinez, CA; Sopchak, David A [Livermore, CA; Upadhye, Ravindra S [Pleasanton, CA; Reynolds, John G [San Ramon, CA; Satcher, Joseph H [Patterson, CA; Gash, Alex E [Brentwood, CA

    2011-11-15

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  8. Catalyst for microelectromechanical systems microreactors

    DOEpatents

    Morse, Jeffrey D [Martinez, CA; Sopchak, David A [Livermore, CA; Upadhye, Ravindra S [Pleasanton, CA; Reynolds, John G [San Ramon, CA; Satcher, Joseph H [Patterson, CA; Gash, Alex E [Brentwood, CA

    2010-06-29

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  9. Catalysts and method

    DOEpatents

    Taylor, Charles E.; Noceti, Richard P.

    1991-01-01

    An improved catlayst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HC1 and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride.

  10. Epoxidation catalyst and process

    DOEpatents

    Linic, Suljo; Christopher, Phillip

    2010-10-26

    Disclosed herein is a catalytic method of converting alkenes to epoxides. This method generally includes reacting alkenes with oxygen in the presence of a specific silver catalyst under conditions suitable to produce a yield of the epoxides. The specific silver catalyst is a silver nanocrystal having a plurality of surface planes, a substantial portion of which is defined by Miller indices of (100). The reaction is performed by charging a suitable reactor with this silver catalyst and then feeding the reactants to the reactor under conditions to carry out the reaction. The reaction may be performed in batch, or as a continuous process that employs a recycle of any unreacted alkenes. The specific silver catalyst has unexpectedly high selectivity for epoxide products. Consequently, this general method (and its various embodiments) will result in extraordinarily high epoxide yields heretofore unattainable.

  11. Reclaim spent catalysts properly

    SciTech Connect

    Lassner, J.A.; Lasher, L.B.; Koppel, R.L.; Hamilton, J.N.

    1994-08-01

    Treatment of spent catalysts and metallic by products has become increasingly more complex over the last couple of years, due to tightening environmental concerns. Three options are available: (1) Reclaiming the metals and either reusing them to make new catalyst or recycling them for other uses. This is now the preferred option. A reclaiming firm is generally employed to handle the task. (2) Regeneration and reuse. While this generally is the preferred option, few commercial catalysts can be regenerated effectively and economically. (3) Landfilling. This has been the traditional route. However, stricter environmental regulations have made landfilling unattractive. To maximize the reclamation both economically and environmentally, five factors should be addressed: (1) proper planning and physical handling; (2) transportation of materials; (3) environmental concerns; (4) end uses of the catalyst; and (5) choosing the proper reclamation partner. These factors are discussed.

  12. Structure and function of real catalysts

    NASA Astrophysics Data System (ADS)

    Klier, K.

    1984-11-01

    such as carbon monoxide or unsaturated hydrocarbons through back-bonding of the copper d-orbitals into the π ∗ orbitals of the substrates. In a paper by D.L. Roberts and G.L. Griffin at this Symposium, additional evidence is presented that the same finely dispersed Cu species are the chemisorption and activation sites for hydrogen. Some significant mechanistic features of carbon monoxide hydrogenation are demonstrated by the enhancement of methanol synthesis rates and carbon-carbon bond formation in the presence of alkali promoters. The nature and concentration of the alkali ions on the catalyst surface determine the outcome of the carbon monoxide hydrogenations in the following way: (i) of all the alkali and alkaline earth promoters, cesium displays the most pronounced effects; (ii) at high temperatures and low hydrogen-to-carbon monoxide ratios, maximum amount of n-propanol and 2-methyl-propanol is observed in the product over the Cs/Cu/ZnO catalysts, consistent with the function of the alkali as base catalysts in aldol condensation of aldehydic or enolic surface intermediates; (iii) at low temperatures and high hydrogen-to-carbon monoxide ratios, cesium enhances methanol synthesis as well as water gas shift rates in water- and CO 2-free synthesis gas, retards the methanol synthesis rate in synthesis gas containing intermediate amounts of water, primarily due to loss of surface area upon cesium doping, and again accelerates the synthesis in water-rich synthesis gas. These latter effects point to a mechanism in which the rate of formation of surface formate is enhanced by cesium in water-free synthesis gas and a rapid removal of surface hydroxyls free sites that activate hydrogen in water-rich synthesis gas. The role of Group VIII metals as promoters of the Cu/ZnO catalysts for low alcohol and hydrocarbon synthesis is represented by the effects of small additions of iron. Product composition is intermediate between that in methanol and Fischer-Tropsch syntheses

  13. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, Rayford G.; Dosch, Robert G.

    1993-01-01

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  14. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, R.G.; Dosch, R.G.

    1993-01-05

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  15. Catalytic reforming catalyst

    SciTech Connect

    Buss, W.C.; Kluksdahl, H.E.

    1980-12-09

    An improved catalyst, having a reduced fouling rate when used in a catalytic reforming process, said catalyst comprising platinum disposed on an alumina support wherein the alumina support is obtained by removing water from aluminum hydroxide produced as a by-product from a ziegler higher alcohol synthesis reaction, and wherein the alumina is calcined at a temperature of 1100-1400/sup 0/F so as to have a surface area of 165 to 215 square meters per gram.

  16. Plasmatron-catalyst system

    SciTech Connect

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander; Alexeev, Nikolai

    2007-10-09

    A plasmatron-catalyst system. The system generates hydrogen-rich gas and comprises a plasmatron and at least one catalyst for receiving an output from the plasmatron to produce hydrogen-rich gas. In a preferred embodiment, the plasmatron receives as an input air, fuel and water/steam for use in the reforming process. The system increases the hydrogen yield and decreases the amount of carbon monoxide.

  17. Plasmatron-catalyst system

    DOEpatents

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander; Alexeev, Nikolai

    2004-09-21

    A plasmatron-catalyst system. The system generates hydrogen-rich gas and comprises a plasmatron and at least one catalyst for receiving an output from the plasmatron to produce hydrogen-rich gas. In a preferred embodiment, the plasmatron receives as an input air, fuel and water/steam for use in the reforming process. The system increases the hydrogen yield and decreases the amount of carbon monoxide.

  18. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOEpatents

    Angelici, Robert J.; Gao, Hanrong

    1998-08-04

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilation, olefin oxidation, isomerization, hydrocyanation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical.

  19. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOEpatents

    Angelici, R.J.; Gao, H.

    1998-08-04

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilication, olefin oxidation, isomerization, hydrocyanidation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical. 2 figs.

  20. Deactivation by carbon of iron catalysts for indirect liquefaction

    SciTech Connect

    Bartholomew, C.H.

    1991-01-10

    Although promoted cobalt and iron catalysts for Fischer-Tropsch (FT) synthesis of gasoline feedstock were first developed more than three decades ago, a major technical problem still limiting the commercial use of these catalysts today is carbon deactivation. This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for FT synthesis, the objectives of which are to: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; and model the rates of deactivation of the same catalysts in fixed-bed reactors. To accomplish the above objectives, the project is divided into the following tasks: (1) determine the kinetics of reaction and of carbon deactivation during CO hydrogenation on Fe and Fe/K catalysts coated on monolith bodies. (2) Determine the reactivities and types of carbon deposited during reaction on the same catalysts from temperature-programmed-surface-reaction spectroscopy (TPSR) and transmission electron microscopy (TEM). Determine the types of iron carbides formed at various temperatures and H{sub 2}/CO ratios using x-ray diffraction and Moessbauer spectroscopy. (3) Develop mathematical deactivation models which include heat and mass transport contributions for FT synthesis is packed-bed reactors. Progress to date is described. 48 refs., 3 figs., 1 tab.

  1. NMR sensor for onboard ship detection of catalytic fines in marine fuel oils.

    PubMed

    Sørensen, Morten K; Vinding, Mads S; Bakharev, Oleg N; Nesgaard, Tomas; Jensen, Ole; Nielsen, Niels Chr

    2014-08-05

    A mobile, low-field nuclear magnetic resonance (NMR) sensor for onboard, inline detection of catalytic fines in fuel oil in the shipping industry is presented as an alternative to onshore laboratory measurements. Catalytic fines (called cat fines) are aluminosilicate zeolite catalysts utilized in the oil cracking process at refineries. When present in fuel oil, cat fines cause abrasive wear of engine parts and may ultimately lead to engine breakdown with large economical consequences, thereby motivating methods for inline measurements. Here, we report on a robust, mobile, and low-cost (27)Al NMR sensor for continuous online measurement of the level of catalytic fines in fuel oil onboard ships. The sensor enables accurate measurements of aluminum (catalytic fines) in ppm concentrations in good agreement with commercial laboratory reference measurements.

  2. Nano Catalysts for Diesel Engine Emission Remediation

    SciTech Connect

    Narula, Chaitanya Kumar; Yang, Xiaofan; Debusk, Melanie Moses; Mullins, David R; Mahurin, Shannon Mark; Wu, Zili

    2012-06-01

    The objective of this project was to develop durable zeolite nanocatalysts with broader operating temperature windows to treat diesel engine emissions to enable diesel engine based equipment and vehicles to meet future regulatory requirements. A second objective was to improve hydrothermal durability of zeolite catalysts to at least 675 C. The results presented in this report show that we have successfully achieved both objectives. Since it is accepted that the first step in NO{sub x} conversion under SCR (selective catalytic reduction) conditions involves NO oxidation to NO{sub 2}, we reasoned that catalyst modification that can enhance NO oxidation at low-temperatures should facilitate NO{sub x} reduction at low temperatures. Considering that Cu-ZSM-5 is a more efficient catalyst than Fe-ZSM-5 at low-temperature, we chose to modify Cu-ZSM-5. It is important to point out that the poor low-temperature efficiency of Fe-ZSM-5 has been shown to be due to selective absorption of NH{sub 3} at low-temperatures rather than poor NO oxidation activity. In view of this, we also reasoned that an increased electron density on copper in Cu-ZSM-5 would inhibit any bonding with NH{sub 3} at low-temperatures. In addition to modified Cu-ZSM-5, we synthesized a series of new heterobimetallic zeolites, by incorporating a secondary metal cation M (Sc{sup 3+}, Fe{sup 3+}, In{sup 3+}, and La{sup 3+}) in Cu exchanged ZSM-5, zeolite-beta, and SSZ-13 zeolites under carefully controlled experimental conditions. Characterization by diffuse-reflectance ultra-violet-visible spectroscopy (UV-Vis), X-ray powder diffraction (XRD), extended X-ray absorption fine structure spectroscopy (EXAFS) and electron paramagnetic resonance spectroscopy (EPR) does not permit conclusive structural determination but supports the proposal that M{sup 3+} has been incorporated in the vicinity of Cu(II). The protocols for degreening catalysts, testing under various operating conditions, and accelerated aging

  3. A study of aluminophosphate supported Ni-Mo catalysts for hydrocracking bitumen

    SciTech Connect

    Smith, K.J.; Lewkowicz, L.; Oballa, M.C.; Krzywicki, A.

    1994-12-31

    H-Oil and LC-Fining processes utilize a combination of thermal and catalytic hydroprocessing reactions to achieve high yields of distillate in upgrading bitumen or heavy oil residua. The processes are based on a well mixed (ebullated bed) reactor from which deactivated catalyst is continuously withdrawn and fresh catalyst is added to maintain yields. Catalyst activity and lifetime are two key factors controlling the economics of these processes. Catalyst deactivation occurs due to the deposition of coke and metals on the catalyst surface. The choice of catalyst is usually a compromise between two extremes: small pore catalyst with low metals capacity but higher activity that deactivates rapidly because of metals deposition and wide pore catalyst that has high metals deposition capacity but lower activity due to low surface area. Recently, aluminophosphate materials with large pores (< 10 nm--1,000 nm) and high surface areas (100--500 m{sup 2}/g) have been reported. The actual pore size distribution and surface area obtained depend on the Al/P ratio, preparation method and the calcination procedure. These materials are also thermally stable. The purpose of the present work was to determine if such materials, as a result of their pore size distribution and surface area, could decrease the rate of catalyst deactivation, increase catalyst activity and provide sufficient pore volume for high capacity of metals deposition during the upgrading of heavy oil residue.

  4. Magnetic and dendritic catalysts.

    PubMed

    Wang, Dong; Deraedt, Christophe; Ruiz, Jaime; Astruc, Didier

    2015-07-21

    The recovery and reuse of catalysts is a major challenge in the development of sustainable chemical processes. Two methods at the frontier between homogeneous and heterogeneous catalysis have recently emerged for addressing this problem: loading the catalyst onto a dendrimer or onto a magnetic nanoparticle. In this Account, we describe representative examples of these two methods, primarily from our research group, and compare them. We then describe new chemistry that combines the benefits of these two methods of catalysis. Classic dendritic catalysis has involved either attaching the catalyst covalently at the branch termini or within the dendrimer core. We have used chelating pyridyltriazole ligands to insolubilize catalysts at the termini of dendrimers, providing an efficient, recyclable heterogeneous catalysts. With the addition of dendritic unimolecular micelles olefin metathesis reactions catalyzed by commercial Grubbs-type ruthenium-benzylidene complexes in water required unusually low amounts of catalyst. When such dendritic micelles include intradendritic ligands, both the micellar effect and ligand acceleration promote faster catalysis in water. With these types of catalysts, we could carry out azide alkyne cycloaddition ("click") chemistry with only ppm amounts of CuSO4·5H2O and sodium ascorbate under ambient conditions. Alternatively we can attach catalysts to the surface of superparamagnetic iron oxide nanoparticles (SPIONs), essentially magnetite (Fe3O4) or maghemite (γ-Fe2O3), offering the opportunity to recover the catalysts using magnets. Taking advantage of the merits of both of these strategies, we and others have developed a new generation of recyclable catalysts: dendritic magnetically recoverable catalysts. In particular, some of our catalysts with a γ-Fe2O3@SiO2 core and 1,2,3-triazole tethers and loaded with Pd nanoparticles generate strong positive dendritic effects with respect to ligand loading, catalyst loading, catalytic activity and

  5. Fine Arts and Humanities: Grade 7. Cluster III.

    ERIC Educational Resources Information Center

    Calhoun, Olivia H.

    A curriculum guide for Grade 7, the document is devoted to the occupational cluster "Fine Arts and Humanities." It is divided into five units: drama and literature, music, dance, art, and crafts. Each unit is introduced by a statement of the topic, the unit's purpose, main ideas, quests, and a list of career opportunities…

  6. Bridging the Digital Divide: Reaching Vulnerable Populations

    PubMed Central

    Chang, Betty L.; Bakken, Suzanne; Brown, S. Scott; Houston, Thomas K.; Kreps, Gary L.; Kukafka, Rita; Safran, Charles; Stavri, P. Zoe

    2004-01-01

    The AMIA 2003 Spring Congress entitled “Bridging the Digital Divide: Informatics and Vulnerable Populations” convened 178 experts including medical informaticians, health care professionals, government leaders, policy makers, researchers, health care industry leaders, consumer advocates, and others specializing in health care provision to underserved populations. The primary objective of this working congress was to develop a framework for a national agenda in information and communication technology to enhance the health and health care of underserved populations. Discussions during four tracks addressed issues and trends in information and communication technologies for underserved populations, strategies learned from successful programs, evaluation methodologies for measuring the impact of informatics, and dissemination of information for replication of successful programs. Each track addressed current status, ideal state, barriers, strategies, and recommendations. Recommendations of the breakout sessions were summarized under the overarching themes of Policy, Funding, Research, and Education and Training. The general recommendations emphasized four key themes: revision in payment and reimbursement policies, integration of health care standards, partnerships as the key to success, and broad dissemination of findings including specific feedback to target populations and other key stakeholders. PMID:15299002

  7. The Digital Divide and urban older adults.

    PubMed

    Cresci, M Kay; Yarandi, Hossein N; Morrell, Roger W

    2010-01-01

    Computers and the Internet offer older adults opportunities and resources for independent living. However, many urban older adults do not use computers. This study examined the demographic, health, and social activities of urban older adults to determine variables that might predict the use and nonuse of computers in this population. A secondary data analysis was performed using the 2001 Detroit City-Wide Needs Assessment of Older Adults (n = 1410) data set. Logistic regression was used to explore potential differences in predictor variables between computer users and nonusers. Overall, computer users were younger (27%), had a higher level of education, were more likely to be employed, had an annual income greater than $20,000, and were healthier and more active than nonusers. They also were more likely to have memberships in community organizations and do volunteer work. Preferred computer activities included conducting Internet searches, playing games, writing, and communicating with family members and friends. The results suggest significant differences in demographic and health-related characteristics between computer users and nonusers among urban older adults. Although about a quarter of participants in this study used computers, the Digital Divide continues to exist in urban settings for scores of others.

  8. Bridging the digital divide: reaching vulnerable populations.

    PubMed

    Chang, Betty L; Bakken, Suzanne; Brown, S Scott; Houston, Thomas K; Kreps, Gary L; Kukafka, Rita; Safran, Charles; Stavri, P Zoe

    2004-01-01

    The AMIA 2003 Spring Congress entitled "Bridging the Digital Divide: Informatics and Vulnerable Populations" convened 178 experts including medical informaticians, health care professionals, government leaders, policy makers, researchers, health care industry leaders, consumer advocates, and others specializing in health care provision to underserved populations. The primary objective of this working congress was to develop a framework for a national agenda in information and communication technology to enhance the health and health care of underserved populations. Discussions during four tracks addressed issues and trends in information and communication technologies for underserved populations, strategies learned from successful programs, evaluation methodologies for measuring the impact of informatics, and dissemination of information for replication of successful programs. Each track addressed current status, ideal state, barriers, strategies, and recommendations. Recommendations of the breakout sessions were summarized under the overarching themes of Policy, Funding, Research, and Education and Training. The general recommendations emphasized four key themes: revision in payment and reimbursement policies, integration of health care standards, partnerships as the key to success, and broad dissemination of findings including specific feedback to target populations and other key stakeholders.

  9. Bridging the Divide between Science and Journalism

    PubMed Central

    2010-01-01

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media. Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings. PMID:20219123

  10. Bridging the divide between science and journalism.

    PubMed

    Van Eperen, Laura; Marincola, Francesco M; Strohm, Jennifer

    2010-03-10

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media.Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings.

  11. Characterisation of gold catalysts.

    PubMed

    Villa, Alberto; Dimitratos, Nikolaos; Chan-Thaw, Carine E; Hammond, Ceri; Veith, Gabriel M; Wang, Di; Manzoli, Maela; Prati, Laura; Hutchings, Graham J

    2016-09-21

    Au-based catalysts have established a new important field of catalysis, revealing specific properties in terms of both high activity and selectivity for many reactions. However, the correlation between the morphology and the activity of the catalyst is not always clear although much effort has been addressed to this task. To some extent the problem relates to the complexity of the characterisation techniques that can be applied to Au catalyst and the broad range of ways in which they can be prepared. Indeed, in many reports only a few characterization techniques have been used to investigate the potential nature of the active sites. The aim of this review is to provide a critical description of the techniques that are most commonly used as well as the more advanced characterization techniques available for this task. The techniques that we discuss are (i) transmission electron microscopy methods, (ii) X-ray spectroscopy techniques, (iii) vibrational spectroscopy techniques and (iv) chemisorption methods. The description is coupled with developing an understanding of a number of preparation methods. In the final section the example of the supported AuPd alloy catalyst is discussed to show how the techniques can gain an understanding of an active oxidation catalyst.

  12. Supported organoiridium catalysts for alkane dehydrogenation

    SciTech Connect

    Baker, R. Thomas; Sattelberger, Alfred P.; Li, Hongbo

    2013-09-03

    Solid supported organoiridium catalysts, a process for preparing such solid supported organoiridium catalysts, and the use of such solid supported organoiridium catalysts in dehydrogenation reactions of alkanes is provided. The catalysts can be easily recovered and recycled.

  13. Porphyrins as Photoredox Catalysts: Experimental and Theoretical Studies.

    PubMed

    Rybicka-Jasińska, Katarzyna; Shan, Wenqian; Zawada, Katarzyna; Kadish, Karl M; Gryko, Dorota

    2016-11-30

    Metalloporphyrins not only are vital in biological systems but also are valuable catalysts in organic synthesis. On the other hand, catalytic properties of free base porphyrins have been less explored. They are mostly known as efficient photosensitizers for the generation of singlet oxygen via photoinduced energy transfer processes, but under light irradiation, they can also participate in electron transfer processes. Indeed, we have found that free base tetraphenylporphyrin (H2TPP) is an efficient photoredox catalyst for the reaction of aldehydes with diazo compounds leading to α-alkylated derivatives. The performance of a porphyrin catalyst can be optimized by tailoring various substituents at the periphery of the macrocycle at both the β and meso positions. This allows for the fine tuning of their optical and electrochemical properties and hence their catalytic activity.

  14. Catalyst reforming process

    SciTech Connect

    Swan, G.A. III

    1989-05-23

    This patent describes a process for catalytically reforming a gasoline boiling range naphtha, with hydrogen, in a semi-regenerative or semi-cyclic reforming process unit comprised of serially connected reactors, inclusive of a lead reactor and one or more downstream reactors, the last of which is the tail reactor, each of which contains a halogenated reforming catalyst comprised of a halide, a Group VIII noble metal, and an inorganic oxide support, the improvement which comprises continuously injecting into each downstream reactor a mixture of water and halide at a water to halide ratio from about 20:1 to about 60:1 wherein the specific ratio of water to halide for each individual downstream reactor is chosen so as to maintain the level of halide on catalyst in each downstream reactor from about 0.5 to 1.5 wt. % based on the total weight of the catalyst.

  15. Oxide Nanocrystal Model Catalysts.

    PubMed

    Huang, Weixin

    2016-03-15

    Model catalysts with uniform and well-defined surface structures have been extensively employed to explore structure-property relationships of powder catalysts. Traditional oxide model catalysts are based on oxide single crystals and single crystal thin films, and the surface chemistry and catalysis are studied under ultrahigh-vacuum conditions. However, the acquired fundamental understandings often suffer from the "materials gap" and "pressure gap" when they are extended to the real world of powder catalysts working at atmospheric or higher pressures. Recent advances in colloidal synthesis have realized controlled synthesis of catalytic oxide nanocrystals with uniform and well-defined morphologies. These oxide nanocrystals consist of a novel type of oxide model catalyst whose surface chemistry and catalysis can be studied under the same conditions as working oxide catalysts. In this Account, the emerging concept of oxide nanocrystal model catalysts is demonstrated using our investigations of surface chemistry and catalysis of uniform and well-defined cuprous oxide nanocrystals and ceria nanocrystals. Cu2O cubes enclosed with the {100} crystal planes, Cu2O octahedra enclosed with the {111} crystal planes, and Cu2O rhombic dodecahedra enclosed with the {110} crystal planes exhibit distinct morphology-dependent surface reactivities and catalytic properties that can be well correlated with the surface compositions and structures of exposed crystal planes. Among these types of Cu2O nanocrystals, the octahedra are most reactive and catalytically active due to the presence of coordination-unsaturated (1-fold-coordinated) Cu on the exposed {111} crystal planes. The crystal-plane-controlled surface restructuring and catalytic activity of Cu2O nanocrystals were observed in CO oxidation with excess oxygen. In the propylene oxidation reaction with O2, 1-fold-coordinated Cu on Cu2O(111), 3-fold-coordinated O on Cu2O(110), and 2-fold-coordinated O on Cu2O(100) were identified

  16. Partial oxidation catalyst

    DOEpatents

    Krumpelt, Michael; Ahmed, Shabbir; Kumar, Romesh; Doshi, Rajiv

    2000-01-01

    A two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion. The dehydrogenation portion is a group VIII metal and the oxide-ion conducting portion is selected from a ceramic oxide crystallizing in the fluorite or perovskite structure. There is also disclosed a method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400.degree. C. for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide.

  17. Catalyst, method of making, and reactions using the catalyst

    DOEpatents

    Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Gao, Yufei [Kennewick, WA

    2009-03-03

    The present invention includes a catalyst having a layered structure with, (1) a porous support, (2) a buffer layer, (3) an interfacial layer, and optionally (4) a catalyst layer. The invention also provides a process in which a reactant is converted to a product by passing through a reaction chamber containing the catalyst.

  18. Catalyst, Method Of Making, And Reactions Using The Catalyst

    DOEpatents

    Tonkovich, Anna Lee Y.; Wang, Yong; Gao, Yufei

    2004-07-13

    The present invention includes a catalyst having a layered structure with, (1) a porous support, (2) a buffer layer, (3) an interfacial layer, and optionally (4) a catalyst layer. The invention also provides a process in which a reactant is converted to a product by passing through a reaction chamber containing the catalyst.

  19. Catalyst, method of making, and reactions using the catalyst

    DOEpatents

    Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Gao, Yufei [Kennewick, WA

    2002-08-27

    The present invention includes a catalyst having a layered structure with, (1) a porous support, (2) a buffer layer, (3) an interfacial layer, and optionally (4) a catalyst layer. The invention also provides a process in which a reactant is converted to a product by passing through a reaction chamber containing the catalyst.

  20. Washability of fine coal

    SciTech Connect

    Cavallaro, J.A.

    1984-01-01

    The objectives of this study are: (1) to determine the theoretical beneficiation potential of US coals when pulverized down to 44 microns, (2) to determine the effects of fine grinding on the liberation of ash, pyritic sulfur, and other impurities, and (3) to assess the impact of their removal on oil and gas replacement, environmental regulations, and specification feedstocks for emerging coal utilization technologies. With the emphasis on fine coal cleaning, we have developed a centrifugal float-sink technique for coals crushed down to 44 microns. Employing this technique will provide a complete fine coal gravimetric evaluation of US coals crushed down to 44 microns. Parallel research is being conducted through in-house studies by PETC, and contracts with the University of Alaska, the University of North Dakota, and Commercial Testing and Engineering, Inc. Results thus far have been encouraging for selected Northern Appalachian Region Coals (NAR), which have shown pyritic sulfur, SO/sub 2/ emission, and ash reductions of 94, 60, and 82%, respectively, for the float 1.30 specific gravity product. However, the data evaluated for several samples indicate a possible problem in the yield/ash relationship for the float 1.30 specific gravity products for samples crushed to 75 and 44 microns top size. Thus, testing was begun to try to resolve these anomalies in the data. Test results using surface active agents, a reverse order of float-sink, and sample pre-heat techniques have been promising. These modifications to the standard technique resulted in an increase in weight recovery of float 1.30 specific gravity material and a decrease in ash content for each of the other specific gravity fractions, thus showing an improvement in the yield/ash relationship.

  1. Secret Lives of Catalysts Revealed

    SciTech Connect

    Salmeron, Miquel; Somorjai, Gabor

    2008-01-01

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-releases/2008/10/21/catalysts/

  2. Very fine Twilights

    NASA Astrophysics Data System (ADS)

    Boico, Vladimir

    1992-04-01

    The author is describing a very fine twilight on 3 January 1992 at 17 h25 m LT (The Sunset was at 16h48m LT) of red - terracotta color. The author is relating this twilight with the volcanic erruption of Pinatubo on the Philipines islands from June 1991. The author is describing the following phenomena related with Volcanic erruption: twilights, the greenish of the Moon's surface, a change in the color of Day Sky to white, Haloes around the Sun. The author is pointing out, that the phenomena mentioned could prolonge in time 2 or 3 years.

  3. Fine needle aspiration cytology.

    PubMed Central

    Lever, J V; Trott, P A; Webb, A J

    1985-01-01

    Fine needle aspiration cytology is an inexpensive, atraumatic technique for the diagnosis of disease sites. This paper describes the technique and illustrates how it may be applied to the management of tumours throughout the body. The limitations of the method, the dangers of false positive reports, and the inevitability of false negative diagnoses are emphasised. In a clinical context the method has much to offer by saving patients from inappropriate operations and investigations and allowing surgeons to plan quickly and more rationally. It is an economically valuable technique and deserves greater recognition. Images PMID:2578481

  4. Finessing fuel fineness

    SciTech Connect

    Storm, R.F.

    2008-10-15

    Most of today's operating coal plants began service at least a generation ago and were designed to burn eastern bituminous coal. A switch to Powder River Basin coal can stress those plants' boiler systems, especially the pulverisers, beyond their design limits and cause no end of operational and maintenance problems. Many of those problems are caused by failing to maintain good fuel fineness when increasing fuel throughput. This article concerns the proper management of the fuel component of the combustion equation in an eight step plan. 8 figs.

  5. Process of making supported catalyst

    DOEpatents

    Schwarz, James A.; Subramanian, Somasundaram

    1992-01-01

    Oxide supported metal catalysts have an additional metal present in intimate association with the metal catalyst to enhance catalytic activity. In a preferred mode, iridium or another Group VIII metal catalyst is supported on a titania, alumina, tungsten oxide, silica, or composite oxide support. Aluminum ions are readsorbed onto the support and catalyst, and reduced during calcination. The aluminum can be added as aluminum nitrate to the iridium impregnate solution, e.g. chloroiridic acid.

  6. The effects of divided attention at study and reporting procedure on regulation and monitoring for episodic recall.

    PubMed

    Sauer, James; Hope, Lorraine

    2016-09-01

    Eyewitnesses regulate the level of detail (grain size) reported to balance competing demands for informativeness and accuracy. However, research to date has predominantly examined metacognitive monitoring for semantic memory tasks, and used relatively artificial phased reporting procedures. Further, although the established role of confidence in this regulation process may affect the confidence-accuracy relation for volunteered responses in predictable ways, previous investigations of the confidence-accuracy relation for eyewitness recall have largely overlooked the regulation of response granularity. Using a non-phased paradigm, Experiment 1 compared reporting and monitoring following optimal and sub-optimal (divided attention) encoding conditions. Participants showed evidence of sacrificing accuracy for informativeness, even when memory quality was relatively weak. Participants in the divided (cf. full) attention condition showed reduced accuracy for fine- but not coarse-grained responses. However, indices of discrimination and confidence diagnosticity showed no effect of divided attention. Experiment 2 compared the effects of divided attention at encoding on reporting and monitoring using both non-phased and 2-phase procedures. Divided attention effects were consistent with Experiment 1. However, compared to those in the non-phased condition, participants in the 2-phase condition displayed a more conservative control strategy, and confidence ratings were less diagnostic of accuracy. When memory quality was reduced, although attempts to balance informativeness and accuracy increased the chance of fine-grained response errors, confidence provided an index of the likely accuracy of volunteered fine-grained responses for both condition.

  7. A divide-and-conquer method for space-time series prediction

    NASA Astrophysics Data System (ADS)

    Deng, Min; Yang, Wentao; Liu, Qiliang; Zhang, Yunfei

    2017-01-01

    Space-time series can be partitioned into space-time smooth and space-time rough, which represent different scale characteristics. However, most existing methods for space-time series prediction directly address space-time series as a whole and do not consider the interaction between space-time smooth and space-time rough in the process of prediction. This will possibly affect the accuracy of space-time series prediction, because the interaction between these two components (i.e., space-time smooth and space-time rough) may cause one of them as dominant component, thus weakening the behavior of the other. Therefore, a divide-and-conquer method for space-time prediction is proposed in this paper. First, the observational fine-grained data are decomposed into two components: coarse-grained data and the residual terms of fine-grained data. These two components are then modeled, respectively. Finally, the predicted values of the fine-grained data are obtained by integrating the predicted values of the coarse-grained data with the residual terms. The experimental results of two groups of different space-time series demonstrated the effectiveness of the divide-and-conquer method.

  8. Fine Channel Networks

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A color image of fine channel networks on Mars; north toward top. The scene shows heavily cratered highlands dissected by dendritic open channel networks that dissect steep slopes of impact crater walls. This image is a composite of Viking high-resolution images in black and white and low-resolution images in color. The image extends from latitude 9 degrees S. to 5 degrees S. and from longitude 312 degrees to 320 degrees; Mercator projection. The dendritic pattern of the fine channels and their location on steep slopes leads to the interpretation that these are runoff channels. The restriction of these types of channels to ancient highland rocks suggests that these channels are old and date from a time on Mars when conditions existed for precipitation to actively erode rocks. After the channels reach a low plain, they appear to end. Termination may have resulted from burial by younger deposits or perhaps the flows percolated into the surface materials and continued underground.

  9. Fine Channel Networks

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A color image of fine channel networks on Mars; north toward top. The scene shows heavily cratered highlands dissected by dendritic open channel networks that dissect steep slopes of impact crater walls. This image is a composite of Viking high-resolution images in black and white and low-resolution images in color. The image extends from latitude 9 degrees S. to 5 degrees S. and from longitude 312 degrees to 320 degrees; Mercator projection. The dendritic pattern of the fine channels and their location on steep slopes leads to the interpretation that these are runoff channels. The restriction of these types of channels to ancient highland rocks suggests that these channels are old and date from a time on Mars when conditions existed for precipitation to actively erode rocks. After the channels reach a low plain, they appear to end. Termination may have resulted from burial by younger deposits or perhaps the flows percolated into the surface materials and continued underground.

  10. Reforming with polymetallic catalysts

    SciTech Connect

    Baird, W.C. Jr.

    1988-11-29

    This patent describes a process for catalytically reforming, with hydrogen, a hydrocarbon naphtha feed at reforming conditions, the improvement comprising contacting the naphtha feed, and hydrogen, with a halogenated, supported platinum-rhenium catalyst promoted with iridium agglomerated to exhibit a crystallinity greater than 50 percent, as measured by X-ray.

  11. Zinc sulfide liquefaction catalyst

    DOEpatents

    Garg, Diwakar

    1984-01-01

    A process for the liquefaction of carbonaceous material, such as coal, is set forth wherein coal is liquefied in a catalytic solvent refining reaction wherein an activated zinc sulfide catalyst is utilized which is activated by hydrogenation in a coal derived process solvent in the absence of coal.

  12. Catalyst, 2000-01.

    ERIC Educational Resources Information Center

    Ryan, Barbara E., Ed.

    2001-01-01

    "Catalyst" is a publication designed to assist higher education in developing alcohol and other drug prevention polices and programs that will foster students' academic and social development and promote campus and community safety. Issue 1 of volume 6 introduces a series of "Presidential Profiles" in which university presidents describe their…

  13. Hydrogen evolution reaction catalyst

    DOEpatents

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  14. Sabatier Catalyst Poisoning Investigation

    NASA Technical Reports Server (NTRS)

    Nallette, Tim; Perry, Jay; Abney, Morgan; Knox, Jim; Goldblatt, Loel

    2013-01-01

    The Carbon Dioxide Reduction Assembly (CRA) on the International Space Station (ISS) has been operational since 2010. The CRA uses a Sabatier reactor to produce water and methane by reaction of the metabolic CO2 scrubbed from the cabin air and the hydrogen byproduct from the water electrolysis system used for metabolic oxygen generation. Incorporating the CRA into the overall air revitalization system has facilitated life support system loop closure on the ISS reducing resupply logistics and thereby enhancing longer term missions. The CRA utilizes CO2 which has been adsorbed in a 5A molecular sieve within the Carbon Dioxide Removal Assembly, CDRA. There is a potential of compounds with molecular dimensions similar to, or less than CO2 to also be adsorbed. In this fashion trace contaminants may be concentrated within the CDRA and subsequently desorbed with the CO2 to the CRA. Currently, there is no provision to remove contaminants prior to entering the Sabatier catalyst bed. The risk associated with this is potential catalyst degradation due to trace organic contaminants in the CRA carbon dioxide feed acting as catalyst poisons. To better understand this risk, United Technologies Aerospace System (UTAS) has teamed with MSFC to investigate the impact of various trace contaminants on the CRA catalyst performance at relative ISS cabin air concentrations and at about 200/400 times of ISS concentrations, representative of the potential concentrating effect of the CDRA molecular sieve. This paper summarizes our initial assessment results.

  15. Salesperson, Catalyst, Manager, Leader.

    ERIC Educational Resources Information Center

    Worth, Michael J.; Asp, James W., II

    1996-01-01

    This article examines four roles of the college or university development officer: salesperson (when direct solicitation is seen as the officer's primary role); catalyst (or sales manager, adviser, expert, facilitator); manager (stressing the importance of the overall office functioning); and leader (who exerts a leadership role in the…

  16. Hydroprocessing catalyst composition

    SciTech Connect

    Apelian, M.R.; Degnan, T.F. Jr.; Marler, D.O.; Mazzone, D.N.

    1993-07-13

    A bifunctional hydroprocessing catalyst is described which comprises a metal component having hydrogenation/dehydrogenation functionality and a support component comprising an inorganic, non-layered, porous, crystalline phase material having pores with diameters of at least about 13 [angstrom] and exhibiting, after calcination, an X-ray diffraction pattern with at least one peak with a relative intensity of 100 at a d-spacing greater than about 18 [angstrom], the catalyst having a surface area S, where S, expressed in m[sup 2].g[sup [minus]1], is defined by the equation: S[ge]600-13.3X where X is the total metals loading in weight percent and is least 12 weight percent. A second hydroprocessing catalyst is described according to claim 1 in which the crystalline phase has a composition expressed as follows: M[sub n/q](W[sub a]X[sub b]Y[sub c]Z[sub d]O[sub h]) wherein M is one or more ions; n is the charge of the composition excluding M expressed as oxides; q is the weighted molar average valence of M; n/q is the number of moles or mole fraction of M; W is one or more divalent elements; X is one or more trivalent elements; Y is one or more tetravalent elements; Z is one or more pentavalent elements; a, b, c, and d are mole fraction of W, X, Y, and Z, respectively, h is a number of from 1 to 2.5; and (a+b+c+d) = 1. A third hydroprocessing catalyst is described according to claim 1 in which the catalyst is at least one base metal of Group VIA, VIIA or VIIIA of the Periodic Table.

  17. Catalyst support structure, catalyst including the structure, reactor including a catalyst, and methods of forming same

    DOEpatents

    Van Norman, Staci A.; Aston, Victoria J.; Weimer, Alan W.

    2017-05-09

    Structures, catalysts, and reactors suitable for use for a variety of applications, including gas-to-liquid and coal-to-liquid processes and methods of forming the structures, catalysts, and reactors are disclosed. The catalyst material can be deposited onto an inner wall of a microtubular reactor and/or onto porous tungsten support structures using atomic layer deposition techniques.

  18. Injection with ultra-fine cement into fine sand layer

    SciTech Connect

    Tamura, Masahito; Goto, Toshiyoshi; Ogino, Takuya; Shimizu, Kazunari

    1994-12-31

    In-situ injection test was carried out in fine sand layer with ordinary portland, colloid and ultra-fine cement. Permeability of the sand layer was 10{sup {minus}3} cm/sec. Suspension grout with ordinary portland and colloid cement was impossible to permeate into the sand. However with ultra fine cement small solidified sand was obtained and with ultra-fine cement-waterglass grout, water cement ratio of 0.8 and waterglass concentration of 75%, solidified sand with expected volume can be obtained.

  19. Molybdenum sulfide/carbide catalysts

    DOEpatents

    Alonso, Gabriel; Chianelli, Russell R.; Fuentes, Sergio; Torres, Brenda

    2007-05-29

    The present invention provides methods of synthesizing molybdenum disulfide (MoS.sub.2) and carbon-containing molybdenum disulfide (MoS.sub.2-xC.sub.x) catalysts that exhibit improved catalytic activity for hydrotreating reactions involving hydrodesulfurization, hydrodenitrogenation, and hydrogenation. The present invention also concerns the resulting catalysts. Furthermore, the invention concerns the promotion of these catalysts with Co, Ni, Fe, and/or Ru sulfides to create catalysts with greater activity, for hydrotreating reactions, than conventional catalysts such as cobalt molybdate on alumina support.

  20. Granulation of fine powder

    DOEpatents

    Chen, Ching-Fong

    2016-08-09

    A mixture of fine powder including thorium oxide was converted to granulated powder by forming a first-green-body and heat treating the first-green-body at a high temperature to strengthen the first-green-body followed by granulation by crushing or milling the heat-treated first-green-body. The granulated powder was achieved by screening through a combination of sieves to achieve the desired granule size distribution. The granulated powder relies on the thermal bonding to maintain its shape and structure. The granulated powder contains no organic binder and can be stored in a radioactive or other extreme environment. The granulated powder was pressed and sintered to form a dense compact with a higher density and more uniform pore size distribution.

  1. Radiology and fine art.

    PubMed

    Marinković, Slobodan; Stošić-Opinćal, Tatjana; Tomić, Oliver

    2012-07-01

    The radiologic aesthetics of some body parts and internal organs have inspired certain artists to create specific works of art. Our aim was to describe the link between radiology and fine art. We explored 13,625 artworks in the literature produced by 2049 artists and found several thousand photographs in an online image search. The examination revealed 271 radiologic artworks (1.99%) created by 59 artists (2.88%) who mainly applied radiography, sonography, CT, and MRI. Some authors produced radiologic artistic photographs, and others used radiologic images to create artful compositions, specific sculptures, or digital works. Many radiologic artworks have symbolic, metaphoric, or conceptual connotations. Radiology is clearly becoming an original and important field of modern art.

  2. Shape-selective sieving layers on an oxide catalyst surface

    NASA Astrophysics Data System (ADS)

    Canlas, Christian P.; Lu, Junling; Ray, Natalie A.; Grosso-Giordano, Nicolas A.; Lee, Sungsik; Elam, Jeffrey W.; Winans, Randall E.; van Duyne, Richard P.; Stair, Peter C.; Notestein, Justin M.

    2012-12-01

    New porous materials such as zeolites, metal-organic frameworks and mesostructured oxides are of immense practical utility for gas storage, separations and heterogeneous catalysis. Their extended pore structures enable selective uptake of molecules or can modify the product selectivity (regioselectivity or enantioselectivity) of catalyst sites contained within. However, diffusion within pores can be problematic for biomass and fine chemicals, and not all catalyst classes can be readily synthesized with pores of the correct dimensions. Here, we present a novel approach that adds reactant selectivity to existing, non-porous oxide catalysts by first grafting the catalyst particles with single-molecule sacrificial templates, then partially overcoating the catalyst with a second oxide through atomic layer deposition. This technique is used to create sieving layers of Al2O3 (thickness, 0.4-0.7 nm) with ‘nanocavities’ (<2 nm in diameter) on a TiO2 photocatalyst. The additional layers result in selectivity (up to 9:1) towards less hindered reactants in otherwise unselective, competitive photocatalytic oxidations and transfer hydrogenations.

  3. Frangible catalyst pretreatment method for use in hydrocarbon hydrodemetallization process

    SciTech Connect

    Eccles, R.M.; Chervenak, M.C.; Li, A.S.U.; Lin, S.J.D.; Malik, V.A.

    1984-06-05

    Activated bauxite particulate material having usual nominal particle size range of 20-50 mesh (U.S. Sieve Series) is treated by fluidization in an upflowing gas so as to attrite the particles and stabilize the particle shape and size, thereby making the catalyst more uniform in shape and resistent to attrition in subsequent ebullated bed reactor operations. The treated activated bauxite catalyst material is then rescreened to provide a narrower differential size range having a particle equivalent diameter ratio range for large to small particles of about 1.4-2.0, and a preferred 20-30 mesh (U.S. Sieve Series) particle size range. The selected pretreated catalyst is then introduced into the ebullated bed reactor of a hydrodemetallization process for hydrocarbon feedstocks containing high metals concentration. Use of such pretreated bauxite catalyst particles results in improved reactor fluidization operations and less catalyst loss by attrition and carryover of fines from the reactor, and achieves improved results of 60-70 W % demetallization and 50-55 V % hydroconversion of the 975/sup 0/ F./sub 30/ fraction to lower boiling hydrcarbon products in a single stage operation.

  4. Automated Camera Array Fine Calibration

    NASA Technical Reports Server (NTRS)

    Clouse, Daniel; Padgett, Curtis; Ansar, Adnan; Cheng, Yang

    2008-01-01

    Using aerial imagery, the JPL FineCalibration (JPL FineCal) software automatically tunes a set of existing CAHVOR camera models for an array of cameras. The software finds matching features in the overlap region between images from adjacent cameras, and uses these features to refine the camera models. It is not necessary to take special imagery of a known target and no surveying is required. JPL FineCal was developed for use with an aerial, persistent surveillance platform.

  5. Helical Oligourea Foldamers as Powerful Hydrogen Bonding Catalysts for Enantioselective C-C Bond-Forming Reactions.

    PubMed

    Bécart, Diane; Diemer, Vincent; Salaün, Arnaud; Oiarbide, Mikel; Nelli, Yella Reddy; Kauffmann, Brice; Fischer, Lucile; Palomo, Claudio; Guichard, Gilles

    2017-09-13

    Substantial progress has been made toward the development of metal-free catalysts of enantioselective transformations, yet the discovery of organic catalysts effective at low catalyst loadings remains a major challenge. Here we report a novel synergistic catalyst combination system consisting of a peptide-inspired chiral helical (thio)urea oligomer and a simple tertiary amine that is able to promote the Michael reaction between enolizable carbonyl compounds and nitroolefins with excellent enantioselectivities at exceptionally low (1/10 000) chiral catalyst/substrate molar ratios. In addition to high selectivity, which correlates strongly with helix folding, the system we report here is also highly amenable to optimization, as each of its components can be fine-tuned separately to increase reaction rates and/or selectivities. The predictability of the foldamer secondary structure coupled to the high level of control over the primary sequence results in a system with significant potential for future catalyst design.

  6. Continuous fine ash depressurization system

    DOEpatents

    Liu, Guohai [Birmingham, AL; Peng, Wan Wang [Birmingham, AL; Vimalchand, Pannalal [Birmingham, AL

    2011-11-29

    A system for depressurizing and cooling a high pressure, high temperature fine solid particles stream having entrained gas therein. In one aspect, the system has an apparatus for cooling the high pressure, high temperature fine solid particles stream having entrained gas therein and a pressure letdown device for depressurization by separating the cooled fine solid particles from a portion of the fine solid particles stream having entrained gas therein, resulting in a lower temperature, lower pressure outlet of solid particles for disposal or handling by downstream equipment.

  7. Selective recovery of catalyst layer from supporting matrix of ceramic-honeycomb-type automobile catalyst.

    PubMed

    Kim, Wantae; Kim, Boungyoung; Choi, Doyoung; Oki, Tatsuya; Kim, Sangbae

    2010-11-15

    Natural resources of platinum group metals (PGMs) are limited and their demand is increasing because of their extensive uses in industrial applications. The low rate of production of PGMs due to low concentration in the related natural ores and high cost of production have made the recovery of PGMs from previously discarded catalytic converters a viable proposition. The ceramic-honeycomb-type automobile catalytic converter contains appreciable amount of PGMs. These valuable substances, which are embedded in the catalyst layer and covered on the surface of the supporting matrix, were selectively recovered by attrition scrubbing. The attrition scrubbing was effective for the selective recovery of catalyst layer. The process was convinced as the comminution and separation process by physical impact and shearing action between particles in the scrubbing vessel. The catalyst layer was dislodged from the surface of the supporting matrix into fine particles by attrition scrubbing. The recovery of Al(2)O(3) and total PGMs in the fraction less than 300 μm increased with the residence time whereas their contents in the recovered materials slightly decreased. The interparticle scrubbing became favorable when the initial input size increased. However, the solid/liquid ratio in the mixing vessel was slightly affected by the low density of converter particles.

  8. Divided Attention Abilities in Young and Old Adults.

    ERIC Educational Resources Information Center

    Somberg, Benjamin L.; Salthouse, Timothy A.

    1982-01-01

    Two experiments on divided attention and adult aging are reported that take into account age differences in single-task performance and that measure divided attention independently of resource allocation strategies. No significant age difference in divided attention ability independent of single-task performance level was found in either…

  9. 20 CFR 404.1207 - Divided retirement system coverage groups.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Divided retirement system coverage groups... of Employees May Be Covered § 404.1207 Divided retirement system coverage groups. (a) General. Under... instrumentalities may divide a retirement system based on whether the employees in positions under that system...

  10. 20 CFR 404.1207 - Divided retirement system coverage groups.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Divided retirement system coverage groups... of Employees May Be Covered § 404.1207 Divided retirement system coverage groups. (a) General. Under... instrumentalities may divide a retirement system based on whether the employees in positions under that system...

  11. 20 CFR 404.1207 - Divided retirement system coverage groups.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Divided retirement system coverage groups... of Employees May Be Covered § 404.1207 Divided retirement system coverage groups. (a) General. Under... instrumentalities may divide a retirement system based on whether the employees in positions under that system...

  12. 20 CFR 404.1207 - Divided retirement system coverage groups.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Divided retirement system coverage groups... of Employees May Be Covered § 404.1207 Divided retirement system coverage groups. (a) General. Under... instrumentalities may divide a retirement system based on whether the employees in positions under that system...

  13. 20 CFR 404.1207 - Divided retirement system coverage groups.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Divided retirement system coverage groups... of Employees May Be Covered § 404.1207 Divided retirement system coverage groups. (a) General. Under... instrumentalities may divide a retirement system based on whether the employees in positions under that system...

  14. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, G.P.; Zhao, J.; Feng, Z.

    1996-12-03

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered. 3 figs.

  15. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, Gerald P.; Zhao, Jianmin; Feng, Zhen

    1996-01-01

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered.

  16. Fluorination process using catalyst

    DOEpatents

    Hochel, Robert C.; Saturday, Kathy A.

    1985-01-01

    A process for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3, AgF.sub.2 and NiF.sub.2, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3 and AgF.sub.2, whereby the fluorination is significantly enhanced.

  17. Fluorination process using catalysts

    DOEpatents

    Hochel, R.C.; Saturday, K.A.

    1983-08-25

    A process is given for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/, AgF/sub 2/ and NiF/sub 2/, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/ and AgF/sub 2/, whereby the fluorination is significantly enhanced.

  18. High-Activity Dealloyed Catalysts

    SciTech Connect

    Kongkanand, Anusorn

    2014-09-30

    Reduction of costly Pt usage in proton exchange membrane fuel cell electrodes is one of the major challenges towards development and commercialization of fuel cell vehicles. Although few have met the initial-kinetic activity requirements in a realistic fuel cell device, no catalyst material has ever met the demanding fuel cell durability targets set by DOE. In this project, a team of 4 universities and 2 companies came together to investigate a concept that appeared promising in preliminary non-fuel cell tests then to further develop the catalyst to a mature level ready for vehicle implementation. The team consists of academia with technical leadership in their respective areas, a catalyst supplier, and a fuel cell system integrator.The tightly collaborative project enabled development of a highly active and durable catalyst with performance that significantly exceeds that of previous catalysts and meets the DOE targets for the first time (Figure 1A). The catalyst was then further evaluated in full-active-area stack in a realistic vehicle operating condition (Figure 1B). This is the first public demonstration that one can realize the performance benefit and Pt cost reduction over a conventional pure Pt catalyst in a long-term realistic PEMFC system. Furthermore, systematic analyses of a range of catalysts with different performance after fuel cell testing allowed for correlation between catalyst microstructure and its electrocatalytic activity and durability. This will in turn aid future catalyst development.

  19. External Catalyst Breakup Phenomena

    DTIC Science & Technology

    1976-06-01

    anhydrous amonia cylinder and associated valve is revealed in the background. Nominal instrumentation for the reactor tests consisted of Temperatures...above the catalyst bed. Liquid, anhydrous ammonia was selected as the quench medium after consideration of the influence water might have on...corresponding to this G Iading and temperature at an amonia dissociation fraction of 0.5 and Lhamber pressure of 200 psia is 18.4 ft/sec. A typical five pound

  20. FCC catalyst selection

    SciTech Connect

    Carter, G.D.L. ); McElhiney, G. )

    1989-09-01

    This paper discusses a commonly used technique for comparing FCC catalytic selectivities based on the ASTM microactivity test (MAT) procedure, ASTM D-3907-80. In its original form the ASTM test provides only very limited information on selectivity. However, extension of the ASTM MAT procedure by using additional product analyses gives a microselectivity test capable of providing detailed yield structure information. This modified MAT procedure thus provides a cost-effective and rapid means of comparing many catalysts.

  1. Steam reforming catalyst

    DOEpatents

    Kramarz, Kurt W.; Bloom, Ira D.; Kumar, Romesh; Ahmed, Shabbir; Wilkenhoener, Rolf; Krumpelt, Michael

    2001-01-01

    A method of forming a hydrogen rich gas from a source of hydrocarbon fuel. A vapor of the hydrocarbon fuel and steam is brought in contact with a two-part catalyst having a dehydrogenation powder portion and an oxide-ion conducting powder portion at a temperature not less than about 770.degree.C. for a time sufficient to generate the hydrogen rich. The H.sub.2 content of the hydrogen gas is greater than about 70 percent by volume. The dehydrogenation portion of the catalyst includes a group VIII metal, and the oxide-ion conducting portion is selected from a ceramic oxide from the group crystallizing in the fluorite or perovskite structure and mixtures thereof. The oxide-ion conducting portion of the catalyst is a ceramic powder of one or more of ZrO.sub.2, CeO.sub.2, Bi.sub.2 O.sub.3, (BiVO).sub.4, and LaGaO.sub.3.

  2. Selective methane oxidation over promoted oxide catalysts. Topical report, September 8, 1992--September 7, 1996

    SciTech Connect

    Klier, K.; Herman, R.G.

    1996-12-31

    The objective of this research was to selectively oxidize methane to C{sub 2} hydrocarbons and to oxygenates, in particular formaldehyde and methanol, in high space time yields using air at the oxidant under milder reaction conditions that heretofore employed over industrially practical oxide catalysts. The research carried out under this US DOE-METC contract was divided into the following three tasks: Task 1, maximizing selective methane oxidation to C{sub 2}{sup +} products over promoted SrO/La{sub 2}O{sub 3} catalysts; Task 2, selective methane oxidation to oxygenates; and Task 3, catalyst characterization and optimization. Principal accomplishments include the following: the 1 wt% SO{sub 4}{sup 2{minus}}/SrO/La{sub 2}O{sub 3} promoted catalyst developed here produced over 2 kg of C{sub 2} hydrocarbons/kg catalyst/hr at 550 C; V{sub 2}O{sub 5}/SiO{sub 2} catalysts have been prepared that produce up to 1.5 kg formaldehyde/kg catalyst/hr at 630 C with low CO{sub 2} selectivities; and a novel dual bed catalyst system has been designed and utilized to produce over 100 g methanol/kg catalyst/hr at 600 C with the presence of steam in the reactant mixture.

  3. A Rhodium Nanoparticle-Lewis Acidic Ionic Liquid Catalyst for the Chemoselective Reduction of Heteroarenes.

    PubMed

    Karakulina, Alena; Gopakumar, Aswin; Akçok, İsmail; Roulier, Bastien L; LaGrange, Thomas; Katsyuba, Sergey A; Das, Shoubhik; Dyson, Paul J

    2016-01-04

    We describe a catalytic system composed of rhodium nanoparticles immobilized in a Lewis acidic ionic liquid. The combined system catalyzes the hydrogenation of quinolines, pyridines, benzofurans, and furan to access the corresponding heterocycles, important molecules present in fine chemicals, agrochemicals, and pharmaceuticals. The catalyst is highly selective, acting only on the heteroaromatic ring, and not interfering with other reducible functional groups.

  4. Chemical composition of Martian fines

    NASA Technical Reports Server (NTRS)

    Clark, B. C.; Baird, A. K.; Weldon, R. J.; Tsusaki, D. M.; Schnabel, L.; Candelaria, M. P.

    1982-01-01

    Of the 21 samples acquired for the Viking X-ray fluorescence spectrometer, 17 were analyzed to high precision. Compared to typical terrestrial continental soils and lunar mare fines, the Martian fines are lower in Al, higher in Fe, and much higher in S and Cl concentrations. Protected fines at the two lander sites are almost indistinguishable, but concentration of the element S is somewhat higher at Utopia. Duricrust fragments, successfully acquired only at the Chryse site, invariably contained about 50% higher S than fines. No elements correlate positively with S, except Cl and possibly Mg. A sympathetic variation is found among the triad Si, Al, Ca; positive correlation occurs between Ti and Fe. Sample variabilities are as great within a few meters as between lander locations (4500 km apart), implying the existence of a universal Martian regolith component of constant average composition. The nature of the source materials for the regolith fines must be mafic to ultramafic.

  5. Bridging the Organizational Divide: Toward a Comprehensive Approach to the Digital Divide. A PolicyLink Report.

    ERIC Educational Resources Information Center

    Kirschenbaum, Josh; Kunamneni, Radhika

    This report discusses innovative uses of information technology by community based organizations, examining how to develop a comprehensive policy agenda for bridging the digital divide. It begins by presenting background information on the digital divide as context for understanding the organizational divide. Next, it discusses challenges facing…

  6. Structural kinetics of a Pt/C cathode catalyst with practical catalyst loading in an MEA for PEFC operating conditions studied by in situ time-resolved XAFS.

    PubMed

    Ishiguro, Nozomu; Saida, Takahiro; Uruga, Tomoya; Sekizawa, Oki; Nagasawa, Kensaku; Nitta, Kiyofumi; Yamamoto, Takashi; Ohkoshi, Shin-ichi; Yokoyama, Toshihiko; Tada, Mizuki

    2013-11-21

    The structural kinetics of surface events on a Pt/C cathode catalyst in a membrane electrode assembly (MEA) with a practical catalyst loading (0.5 mgPt cm(-2)) for a polymer electrolyte fuel cell were investigated by in situ time-resolved X-ray absorption fine structure analysis (XAFS; time resolution: 100 ms) for the first time. The rate constants of structural changes in the Pt/C cathode catalyst in the MEA during voltage cycling were successfully estimated. For voltage-cycling processes, all reactions (electrochemical reactions and structural changes in the Pt catalyst) in the MEA were found to be much faster than those in an MEA with a thick cathode catalyst layer, but the in situ time-resolved XAFS analysis revealed that significant time lags similarly existed between the electrochemical reactions and the structural changes in the Pt cathode catalyst. The time-resolved XAFS also revealed differences in the structural kinetics of the Pt/C cathode catalyst for the voltage-cycling processes under N2 and air flows at the cathode.

  7. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, W.M.H.; Tzou, M.S.; Jiang, H.J.

    1987-03-31

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  8. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, Wolfgang M. H.; Tzou, Ming-Shin; Jiang, Hui-Jong

    1987-01-01

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  9. Catalyst systems and uses thereof

    DOEpatents

    Ozkan, Umit S [Worthington, OH; Holmgreen, Erik M [Columbus, OH; Yung, Matthew M [Columbus, OH

    2012-07-24

    A method of carbon monoxide (CO) removal comprises providing an oxidation catalyst comprising cobalt supported on an inorganic oxide. The method further comprises feeding a gaseous stream comprising CO, and oxygen (O.sub.2) to the catalyst system, and removing CO from the gaseous stream by oxidizing the CO to carbon dioxide (CO.sub.2) in the presence of the oxidation catalyst at a temperature between about 20 to about 200.degree. C.

  10. Development of GREET Catalyst Module

    SciTech Connect

    Wang, Zhichao; Benavides, Pahola T.; Dunn, Jennifer B.; Cronauer, Donald C.

    2015-09-01

    In this report, we develop energy and material flows for the production of five different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5], Mo/Co/ γ-Al2O3, and Pt/ γ-Al2O3) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module.

  11. Oxygen-reducing catalyst layer

    DOEpatents

    O'Brien, Dennis P [Maplewood, MN; Schmoeckel, Alison K [Stillwater, MN; Vernstrom, George D [Cottage Grove, MN; Atanasoski, Radoslav [Edina, MN; Wood, Thomas E [Stillwater, MN; Yang, Ruizhi [Halifax, CA; Easton, E Bradley [Halifax, CA; Dahn, Jeffrey R [Hubley, CA; O'Neill, David G [Lake Elmo, MN

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  12. Spent catalyst processing with electrochemistry

    SciTech Connect

    Silva, L.J.; Bray, L.A.; Frye, J.G.; Buehler, M.F.

    1994-11-01

    Increasing concern for pollution prevention and waste disposal has created a need for clean alternatives for spent catalyst processing. In addition, expanded use of catalysts for the production of fuels and chemical feedstocks will continue in response to (1) economic pressure to upgrade heavier crudes and other feeds having high levels of impurities; (2) competitive pressure to achieve higher conversions using less energy; and (3) pressure to increase reaction selectivities to minimize waste production. While the incentives for using catalysts are great, all catalysts gradually lose activity through coking; poisoning by metals, sulfur, or halides; or loss of surface area from sintering at high process temperatures. Regeneration is possible where the catalyst deactivation can easily be reversed. Electrochemical dissolution is a new technique to oxidize catalyst contaminants and dissolve catalyst metals in an aqueous solution for further recovery of the raw materials. The key to this process is adding spent catalyst to a solution containing small amounts of species that form kinetically active, strongly oxidizing ions such as cerium(IV) or silver(II). The oxidizing ions are regenerated at the anode; they act in a catalytic manner carrying electrons from the solid surface to the anode of the electrochemical cell. A cerium oxidizer was used for the experiments described in this paper. For this procedure, solution is added to the anode side of an electrochemical cell. At the anode, aqueous cerium(III) is oxidized to cerium(IV). The cerium(IV), in turn, oxidizes organic material adhered to the catalyst to carbon dioxide and water. Many spent catalysts used in hydrogenations contain metal sulfides that have contaminated the catalyst surface during processing. Metal sulfides are oxidized to dissolved metal ions and sulfur species. Because cerium is continuously reoxidized to cerium(IV) at the anode, a small amount of cerium is needed to oxidize the spent catalyst.

  13. Results of catalyst testing using iron-based catalysts

    SciTech Connect

    Linehan, J.C.; Darab, J.G.; Matson, D.W.

    1993-03-01

    As coal liquefaction catalysts, iron-based products are generally inferior to the more expensive molybdenum, cobalt, or nickel-based materials. However, the lower costs of production and recovery (or in the case of some iron catalysts, non-recovery) give the iron-based materials a potential economic advantage over the more efficient precious and semi-precious metal catalysts for this application. Recent research has shown that a number of different iron-containing materials can be successfully utilized as coal liquefaction catalysts or as catalyst. Pyrrhotite (Fe{sub 1-x}S) or a similar iron-sulfide phase is commonly believed to be the active catalyst in coal liquefaction and model compound pyrolysis reactions, although no specific phase has been yet been isolated as the actual catalyst species. The active iron-containing catalyst is usually generated in situ from an iron-oxide precursor and an elemental sulfur source under reducing conditions in the reactor vessel. Most research has concentrated on the use of common iron-oxide phases such as hematite or goethite (and their derivatives) as the iron-bearing precursor, or on non-specific iron materials produced by the reaction of various iron salts and compounds in the coal or liquefaction reactor. To our knowledge there has been no systematic effort to determine the optimum iron-containing precursor phase for producing active coal liquefaction catalysts, despite the fact that there are over ten iron-(hydroxy)oxide phases which can be easily synthesized in the laboratory. We have undertaken a systematic study to identify the most active iron-oxide catalyst precursor phases, the co-catalysts, and the coal pretreatments which will provide optimum yields in coal liquefaction processes.

  14. Results of catalyst testing using iron-based catalysts

    SciTech Connect

    Linehan, J.C.; Darab, J.G.; Matson, D.W.

    1993-03-01

    As coal liquefaction catalysts, iron-based products are generally inferior to the more expensive molybdenum, cobalt, or nickel-based materials. However, the lower costs of production and recovery (or in the case of some iron catalysts, non-recovery) give the iron-based materials a potential economic advantage over the more efficient precious and semi-precious metal catalysts for this application. Recent research has shown that a number of different iron-containing materials can be successfully utilized as coal liquefaction catalysts or as catalyst. Pyrrhotite (Fe[sub 1-x]S) or a similar iron-sulfide phase is commonly believed to be the active catalyst in coal liquefaction and model compound pyrolysis reactions, although no specific phase has been yet been isolated as the actual catalyst species. The active iron-containing catalyst is usually generated in situ from an iron-oxide precursor and an elemental sulfur source under reducing conditions in the reactor vessel. Most research has concentrated on the use of common iron-oxide phases such as hematite or goethite (and their derivatives) as the iron-bearing precursor, or on non-specific iron materials produced by the reaction of various iron salts and compounds in the coal or liquefaction reactor. To our knowledge there has been no systematic effort to determine the optimum iron-containing precursor phase for producing active coal liquefaction catalysts, despite the fact that there are over ten iron-(hydroxy)oxide phases which can be easily synthesized in the laboratory. We have undertaken a systematic study to identify the most active iron-oxide catalyst precursor phases, the co-catalysts, and the coal pretreatments which will provide optimum yields in coal liquefaction processes.

  15. Mixed Alcohol Synthesis Catalyst Screening

    SciTech Connect

    Gerber, Mark A.; White, James F.; Stevens, Don J.

    2007-09-03

    National Renewable Energy Laboratory (NREL) and Pacific Northwest National Laboratory (PNNL) are conducting research to investigate the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). PNNL is tasked with obtaining commercially available or preparing promising mixed-alcohol catalysts and screening them in a laboratory-scale reactor system. Commercially available catalysts and the most promising experimental catalysts are provided to NREL for testing using a slipstream from a pilot-scale biomass gasifier. From the standpoint of producing C2+ alcohols as the major product, it appears that the rhodium catalyst is the best choice in terms of both selectivity and space-time yield (STY). However, unless the rhodium catalyst can be improved to provide minimally acceptable STYs for commercial operation, mixed alcohol synthesis will involve significant production of other liquid coproducts. The modified Fischer-Tropsch catalyst shows the most promise for providing both an acceptable selectivity to C2+ alcohols and total liquid STY. However, further optimization of the Fischer-Tropsch catalysts to improve selectivity to higher alcohols is highly desired. Selection of a preferred catalyst will likely entail a decision on the preferred coproduct slate. No other catalysts tested appear amenable to the significant improvements needed for acceptable STYs.

  16. DEHYDROGENATION CATALYST FOR PRODUCTION OF MTBE

    EPA Science Inventory

    The objectives of this project were to better understand the effect of different catalyst preparation parameters, the effect of different catalyst treatment parameters, and the mechanism of deactivation. Accordingly, catalysts were made using various preparation methods and with...

  17. DEHYDROGENATION CATALYST FOR PRODUCTION OF MTBE

    EPA Science Inventory

    The objectives of this project were to better understand the effect of different catalyst preparation parameters, the effect of different catalyst treatment parameters, and the mechanism of deactivation. Accordingly, catalysts were made using various preparation methods and with...

  18. 'RAT' Leaves a Fine Mess

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This graph shows the light signatures, or spectra, of two sides of the rock dubbed 'Bounce,' located at Meridiani Planum, Mars. The spectra were taken by the miniature thermal emission spectrometer on the Mars Exploration Rover Opportunity. The left side of this rock is covered by fine dust created when the rover drilled into the rock with its rock abrasion tool. These 'fines' produce a layer of pyroxene dust that can be detected here in the top spectrum. The right side of the rock has fewer fines and was used to investigate the composition of this basaltic rock.

  19. Uprated fine guidance sensor study

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Future orbital observatories will require star trackers of extremely high precision. These sensors must maintain high pointing accuracy and pointing stability simultaneously with a low light level signal from a guide star. To establish the fine guidance sensing requirements and to evaluate candidate fine guidance sensing concepts, the Space Telescope Optical Telescope Assembly was used as the reference optical system. The requirements review was separated into three areas: Optical Telescope Assembly (OTA), Fine Guidance Sensing and astrometry. The results show that the detectors should be installed directly onto the focal surface presented by the optics. This would maximize throughput and minimize point stability error by not incoporating any additional optical elements.

  20. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    SciTech Connect

    James K. Neathery; Gary Jacobs; Amitava Sarkar; Burtron H. Davis

    2005-09-30

    In this reporting period, a study of ultra-fine iron catalyst filtration was initiated to study the behavior of ultra-fine particles during the separation of Fischer-Tropsch Synthesis (FTS) liquids filtration. The overall focus of the program is with slurry-phase FTS in slurry bubble column reactor systems. Hydrocarbon products must be separated from catalyst particles before being removed from the reactor system. An efficient wax product/catalyst separation system is a key factor for optimizing operating costs for iron-based slurry-phase FTS. Previous work has focused on catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. With the current study, we are investigating how the filtration properties are affected by these chemical and physical changes of the catalyst slurry during activation/synthesis. The change of particle size during the slurry-phase FTS has monitored by withdrawing catalyst sample at different TOS. The measurement of dimension of the HRTEM images of samples showed a tremendous growth of the particles. Carbon rims of thickness 3-6 nm around the particles were observed. This growth in particle size was not due to carbon deposition on the catalyst. A conceptual design and operating philosophy was developed for an integrated wax filtration system for a 4 liter slurry bubble column reactor to be used in Phase II of this research program. The system will utilize a primary inertial hydroclone followed by a Pall Accusep cross-flow membrane. Provisions for cleaned permeate back-pulsing will be included to as a flux maintenance measure.

  1. Molecular water oxidation catalyst

    DOEpatents

    Gratzel, Michael; Munavalli, Shekhar; Pern, Fu-Jann; Frank, Arthur J.

    1993-01-01

    A dimeric composition of the formula: ##STR1## wherein L', L", L'", and L"" are each a bidentate ligand having at least one functional substituent, the ligand selected from bipyridine, phenanthroline, 2-phenylpyridine, bipyrimidine, and bipyrazyl and the functional substituent selected from carboxylic acid, ester, amide, halogenide, anhydride, acyl ketone, alkyl ketone, acid chloride, sulfonic acid, phosphonic acid, and nitro and nitroso groups. An electrochemical oxidation process for the production of the above functionally substituted bidentate ligand diaqua oxo-bridged ruthenium dimers and their use as water oxidation catalysts is described.

  2. Novel Reforming Catalysts

    SciTech Connect

    Pfefferle, Lisa D; Haller, Gary L

    2012-10-16

    Aqueous phase reforming is useful for processing oxygenated hydrocarbons to hydrogen and other more useful products. Current processing is hampered by the fact that oxide based catalysts are not stable under high temperature hydrothermal conditions. Silica in the form of structured MCM-41 is thermally a more stable support for Co and Ni than conventional high surface area amorphous silica but hydrothermal stability is not demonstrated. Carbon nanotube supports, in contrast, are highly stable under hydrothermal reaction conditions. In this project we show that carbon nanotubes are stable high activity/selectivity supports for the conversion of ethylene glycol to hydrogen.

  3. An Empirical Analysis of the Determinants of International Digital Divide

    NASA Astrophysics Data System (ADS)

    Yun, Liu

    International Digital Divide is an imbalance state of ICT penetration between countries. This paper analyzes the current status and trends of international digital divide, adopts Gompertz technology diffusion model to verify the determinants of ICT penetration level and diffusion rate separately. Finally, China should use "policy levers" to strengthen international trade cooperation, improve the capability of independent innovation, and achieve Chinese goal of bridging digital divide.

  4. Shape-selective catalysts for Fischer-Tropsch chemistry : iron-containing particulate catalysts. Activity report : January 1, 2001 - December 31, 2004.

    SciTech Connect

    Cronauer, D.; Chemical Engineering

    2006-05-12

    Argonne National Laboratory is carrying out a research program to create, prepare, and evaluate catalysts to promote Fischer-Tropsch (FT) chemistry--specifically, the reaction of hydrogen with carbon monoxide to form long-chain hydrocarbons. In addition to needing high activity, it is desirable that the catalysts have high selectivity and stability with respect to both mechanical strength and aging properties. It is desired that selectivity be directed toward producing diesel fraction components and avoiding excess yields of both light hydrocarbons and heavy waxes. The goal is to produce shape-selective catalysts that have the potential to limit the formation of longchain products and yet retain the active metal sites in a protected 'cage'. This cage also restricts their loss by attrition during use in slurry-bed reactors. The first stage of this program was to prepare and evaluate iron-containing particulate catalysts. This activity report centers upon this first stage of experimentation with particulate FT catalysts. (For reference, a second experimental stage is under way to prepare and evaluate active FT catalysts formed by atomic-layer deposition [ALD] of active components on supported membranes.) To date, experimentation has centered upon the evaluation of a sample of iron-based, spray-dried catalyst prepared by B.H. Davis of the Center of Applied Energy Research (CAER) and samples of his catalyst onto which inorganic 'shells' were deposited. The reference CAER catalyst contained a high level of dispersed fine particles, a portion of which was removed by differential settling. Reaction conditions have been established using a FT laboratory unit such that reasonable levels of CO conversion can be achieved, where therefore a valid catalyst comparison can be made. A wide range of catalytic activities was observed with SiO{sub 2}-coated FT catalysts. Two techniques were used for SiO{sub 2}coating. The first involved a caustic precipitation of SiO{sub 2} from an

  5. Alkene metathesis: the search for better catalysts.

    PubMed

    Deshmukh, Prashant H; Blechert, Siegfried

    2007-06-28

    Alkene metathesis catalyst development has made significant progress over recent years. Research in metathesis catalyst design has endeavoured to tackle three key issues: those of (i) catalyst efficiency and activity, (ii) substrate scope and selectivity--particularly stereoselective metathesis reactions--and (iii) the minimization of metal impurities and catalyst recycling. This article describes a brief history of metathesis catalyst development, followed by a survey of more recent research, with a particular emphasis on ruthenium catalysts.

  6. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    SciTech Connect

    Amitava Sarkar; James K. Neathery; Burtron H. Davis

    2006-12-31

    A fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of operation since the reaction is highly exothermic. Consequently, heavy wax products in one approach may be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase iron-based FTS and is a key factor for optimizing operating costs. The separation problem is further compounded by attrition of iron catalyst particles and the formation of ultra-fine particles.

  7. Chemoselective single-site Earth-abundant metal catalysts at metal–organic framework nodes

    SciTech Connect

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X.; Urban, Ania; Thacker, Nathan C.; Lin, Wenbin

    2016-08-30

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal–organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C–H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

  8. Carbon nanocages: a new support material for Pt catalyst with remarkably high durability.

    PubMed

    Wang, Xiao Xia; Tan, Zhe Hua; Zeng, Min; Wang, Jian Nong

    2014-03-24

    Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology, and corrosion of carbon support materials of current catalysts is the main cause. Here, we describe the finding of remarkably high durability with the use of a novel support material. This material is based on hollow carbon nanocages developed with a high degree of graphitization and concurrent nitrogen doping for oxidation resistance enhancement, uniform deposition of fine Pt particles, and strong Pt-support interaction. Accelerated degradation testing shows that such designed catalyst possesses a superior electrochemical activity and long-term stability for both hydrogen oxidation and oxygen reduction relative to industry benchmarks of current catalysts. Further testing under conditions of practical fuel cell operation reveals almost no degradation over long-term cycling. Such a catalyst of high activity, particularly, high durability, opens the door for the next-generation PEMFC for "real world" application.

  9. Carbon nanocages: A new support material for Pt catalyst with remarkably high durability

    PubMed Central

    Wang, Xiao Xia; Tan, Zhe Hua; Zeng, Min; Wang, Jian Nong

    2014-01-01

    Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology, and corrosion of carbon support materials of current catalysts is the main cause. Here, we describe the finding of remarkably high durability with the use of a novel support material. This material is based on hollow carbon nanocages developed with a high degree of graphitization and concurrent nitrogen doping for oxidation resistance enhancement, uniform deposition of fine Pt particles, and strong Pt-support interaction. Accelerated degradation testing shows that such designed catalyst possesses a superior electrochemical activity and long-term stability for both hydrogen oxidation and oxygen reduction relative to industry benchmarks of current catalysts. Further testing under conditions of practical fuel cell operation reveals almost no degradation over long-term cycling. Such a catalyst of high activity, particularly, high durability, opens the door for the next-generation PEMFC for “real world” application. PMID:24658614

  10. Chemoselective single-site Earth-abundant metal catalysts at metal-organic framework nodes.

    PubMed

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X; Urban, Ania; Thacker, Nathan C; Lin, Wenbin

    2016-08-30

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal-organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C-H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

  11. Carbon nanocages: A new support material for Pt catalyst with remarkably high durability

    NASA Astrophysics Data System (ADS)

    Wang, Xiao Xia; Tan, Zhe Hua; Zeng, Min; Wang, Jian Nong

    2014-03-01

    Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology, and corrosion of carbon support materials of current catalysts is the main cause. Here, we describe the finding of remarkably high durability with the use of a novel support material. This material is based on hollow carbon nanocages developed with a high degree of graphitization and concurrent nitrogen doping for oxidation resistance enhancement, uniform deposition of fine Pt particles, and strong Pt-support interaction. Accelerated degradation testing shows that such designed catalyst possesses a superior electrochemical activity and long-term stability for both hydrogen oxidation and oxygen reduction relative to industry benchmarks of current catalysts. Further testing under conditions of practical fuel cell operation reveals almost no degradation over long-term cycling. Such a catalyst of high activity, particularly, high durability, opens the door for the next-generation PEMFC for ``real world'' application.

  12. Chemoselective single-site Earth-abundant metal catalysts at metal-organic framework nodes

    NASA Astrophysics Data System (ADS)

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X.; Urban, Ania; Thacker, Nathan C.; Lin, Wenbin

    2016-08-01

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal-organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C-H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

  13. New fine structure cooling rate

    NASA Technical Reports Server (NTRS)

    Hoegy, W. R.

    1976-01-01

    One of the dominant electron cooling processes in the ionosphere is caused by electron impact induced fine structure transitions among the ground state levels of atomic oxygen. This fine structure cooling rate is based on theoretical cross sections. Recent advances in the numerical cross section determinations to include polarization effects and more accurate representations of the atomic target result in new lower values. These cross sections are employed in this paper to derive a new fine structure cooling rate which is between 40% and 60% of the currently used rate. A new generalized formula is presented for the cooling rate (from which the fine structure cooling rate is derived), valid for arbitrary mass and temperature difference of the colliding particles and arbitrary inelastic energy difference.

  14. Catalyst separation method reduces Platformer turnaround costs

    SciTech Connect

    Blashka, S.R.; Welch, J.G.; Nite, K.; Furfaro, A.P.

    1995-09-18

    A catalyst separation technology that segregates catalyst particles by density has proved successful in recovering CCR (continuous catalyst regeneration) Platforming catalyst that had been contaminated with heel catalyst, non-flowing catalyst. UOP`s CCR Platforming process converts naphtha to high-octane gasoline components and aromatics for petrochemical use. The reforming reactions take place in a series of Platforming reactors loaded with platinum-containing reforming catalyst. CCR Platforming technology incorporates a moving catalyst bed in a system that permits addition and withdrawal of catalyst from the reactor while the unit is operating. As the catalyst circulates through the reactors, it builds up typical carbon levels of 5%. Over time, the heel catalyst will build up carbon levels as high as 50%. When the catalyst is unloaded, heel catalyst is released, contaminating the last fraction of catalyst removed from the reactor. The heel-contaminated catalyst should not be reused because only a small fraction of the carbon on the heel catalyst is removed in the regeneration section. If returned to inventory, the carbon would react rapidly, causing temperature excursions. If heel-contaminated catalyst is reused, there is a high potential for damage to the unit. Density grading was used, after ex situ regeneration to recover the uncontaminated catalyst for reuse.

  15. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Technical progress report, October--December 1992

    SciTech Connect

    Song, Chunshan; Schobert, H.H.

    1993-02-01

    Development of new catalysts is a promising approach to more efficient coal liquefaction. It has been recognized that catalysts are superior to supported catalysts for primary liquefaction of coals, because the control of initial coal dissolution or depolymerization requires intimate contact between the catalyst and coal. This research is a fundamental and exploratory study on catalytic coal liquefaction, with the emphasis on the development of novel bimetallic dispersed catalysts for temperature-programmed liquefaction. The ultimate goal of the present research is to develop novel catalytic hydroliquefaction process using highly active dispersed catalysts. The primary objective of this research is to develop novel bimetallic dispersed catalysts from organometallic molecular that can be used in low precursors concentrations (< 1 %) but exhibit high activity for efficient hydroliquefaction of coals under temperature-programmed conditions. The major technical approaches are, first, to prepare the desired heteronuclear organometallic molecules as catalyst precursors that contain covalently bound, two different metal atoms and sulfur in a single molecule. Such precursors will generate finely dispersed bimetallic catalysts such as Fe-Mo, Co-Mo and Ni-Mo binary sulfides upon thermal decomposition. The second major technical approach is to perform the liquefaction of coals unpregnated with the organometallic precursors under temperature-programmed conditions, where the programmed heat-up serves as a step for both catalyst activation and coal pretreatment or preconversion. Two to three different complexes for each of the Fe-Mo, Co-Mo, and Ni-Mo combinations will be prepared. Initial catalyst screening tests will be conducted using a subbituminous coal and a bituminous coal. Effects of coal rank and solvents will be examined with the selected bimetallic catalysts which showed much higher activity than the dispersed catalysts from conventional precursors.

  16. Startup procedure for reforming catalysts

    SciTech Connect

    McHale, W.D.; Schoennagel, H.J.

    1984-08-14

    Process for reforming a hydrocarbon charge under reforming conditions in a reforming zone containing a sulfur-sensitive metal containing reforming catalyst wherein over-cracking of the charge stock and excessive temperature rise in the reforming zone is suppressed by pre-conditioning the catalyst, prior to contact with the charge, with a reformate of specified octane number and aromatics content.

  17. Catalysts for low temperature oxidation

    DOEpatents

    Toops, Todd J.; Parks, III, James E.; Bauer, John C.

    2016-03-01

    The invention provides a composite catalyst containing a first component and a second component. The first component contains nanosized gold particles. The second component contains nanosized platinum group metals. The composite catalyst is useful for catalyzing the oxidation of carbon monoxide, hydrocarbons, oxides of nitrogen, and other pollutants at low temperatures.

  18. Transition metal sulfide loaded catalyst

    DOEpatents

    Maroni, V.A.; Iton, L.E.; Pasterczyk, J.W.; Winterer, M.; Krause, T.R.

    1994-04-26

    A zeolite-based catalyst is described for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C[sub 2]+ hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

  19. Transition metal sulfide loaded catalyst

    DOEpatents

    Maroni, Victor A.; Iton, Lennox E.; Pasterczyk, James W.; Winterer, Markus; Krause, Theodore R.

    1994-01-01

    A zeolite based catalyst for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C.sub.2 + hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

  20. Doped palladium containing oxidation catalysts

    SciTech Connect

    Mohajeri, Nahid

    2014-02-18

    A supported oxidation catalyst includes a support having a metal oxide or metal salt, and mixed metal particles thereon. The mixed metal particles include first particles including a palladium compound, and second particles including a precious metal group (PMG) metal or PMG metal compound, wherein the PMG metal is not palladium. The oxidation catalyst may also be used as a gas sensor.

  1. Zeolites for reforming catalysts

    SciTech Connect

    Kao, J.L.; Nadler, M.; Potter, M.J.; Martir, R.V.

    1991-01-22

    This patent describes a reforming catalyst exhibiting enhanced selectivity, activity, and activity maintenance. It comprises: zeolite crystals having a pH within the range of 9.4 to 10.0, wherein the pH is determined by measuring pH of supernatent liquid from a mixture of one part of the zeolite crystals with ten parts of dionized water by weight, and comprising exchangeable cations and at least one catalytically active metal selected from the group consisting of Group VII of the Periodic Table of Elements, tin and germanium. This patten also describes a process for treating zeolite to have a pH within a range effective in imparting enhanced activity, selectivity and activity maintenance to catalysts loaded onto the zeolite. The process comprising washing zeolite with an aqueous liquid in a manner so as to result with zeolite having a pH within the pH range of 9.4 to 10.0. The PH of supernatent liquid from a mixture of one part of the zeolite crystals with ten parts of dionized water by weight.

  2. Prelife catalysts and replicators

    PubMed Central

    Ohtsuki, Hisashi; Nowak, Martin A.

    2009-01-01

    Life is based on replication and evolution. But replication cannot be taken for granted. We must ask what there was prior to replication and evolution. How does evolution begin? We have proposed prelife as a generative system that produces information and diversity in the absence of replication. We model prelife as a binary soup of active monomers that form random polymers. ‘Prevolutionary’ dynamics can have mutation and selection prior to replication. Some sequences might have catalytic activity, thereby enhancing the rates of certain prelife reactions. We study the selection criteria for these prelife catalysts. Their catalytic efficiency must be above certain critical values. We find a maintenance threshold and an initiation threshold. The former is a linear function of sequence length, and the latter is an exponential function of sequence length. Therefore, it is extremely hard to select for prelife catalysts that have long sequences. We compare prelife catalysis with a simple model for replication. Assuming fast template-based elongation reactions, we can show that replicators have selection thresholds that are independent of their sequence length. Our calculation demonstrates the efficiency of replication and provides an explanation of why replication was selected over other forms of prelife catalysis. PMID:19692408

  3. Catalysts Encapsulated in Molecular Machines.

    PubMed

    Pan, Tiezheng; Liu, Junqiu

    2016-06-17

    Smart catalysts offer the control of chemical processes and sequences of transformations, and catalysts with unique catalytic behavior can afford chiral products or promote successive polymerization. To meet advanced demands, the key to constructing smart catalysts is to incorporate traditional catalytic functional groups with trigger-induced factors. Molecular machines with dynamic properties and particular topological structures have typical stimulus-responsive features. In recent years, scientists have made efforts to utilize molecular machines (molecular switches, rotaxanes, motors, etc.) as scaffolds to develop smart catalysts. This Minireview focuses on the achievements of developing catalysts encapsulated in molecular machines and their remarkable specialties. This strategy is believed to provide more potential applications in switchable reactions, asymmetric synthesis, and processive catalysis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Timescales of landscape response to divide migration and drainage capture: Implications for the role of divide mobility in landscape evolution

    NASA Astrophysics Data System (ADS)

    Whipple, K. X.; Forte, A. M.; DiBiase, R. A.; Gasparini, N. M.; Ouimet, W. B.

    2017-01-01

    Efforts to extract information about climate and tectonics from topography commonly assume that river networks are static. Drainage divides can migrate through time, however, and recent work has shown that divide mobility can potentially induce changes in river profiles comparable to changes caused by variation in rock uplift, climate, or rock properties. We use 1-D river profile and 2-D landscape evolution simulations to evaluate how mobile divides influence the interpretation of river profiles in tectonically active settings. We define a nondimensional divide migration number, NDm, as the ratio of the timescale of channel profile response to a change in drainage area (TdA) to the timescale of divide migration (TDm). In simulations of headward divide migration, NDm is much less than unity with no measurable perturbation of channel profiles. Only in simulations configured to induce rapid lateral divide migration are there occasional large stream capture events and zones where localized drainage area loss is fast enough to support NDm values near unity. The rapid response of channel profiles to changes in drainage area ensures that under most conditions profiles maintain quasi-equilibrium forms and thus generally reflect spatiotemporal variation in rock uplift, climate, or rock properties even during active divide migration. This implies that channel profile form may not reliably record divide mobility, so we evaluate alternate metrics of divide mobility. In our simulations and an example in Taiwan, we find that simple measures of cross-divide contrasts in topography are more robust metrics of divide mobility than measures of drainage network topology.

  5. Litterfall production and fine root dynamics in cool-temperate forests

    PubMed Central

    Chun, Jung Hwa; Osawa, Akira

    2017-01-01

    Current understanding of litterfall and fine root dynamics in temperate forests is limited, even though these are the major contributors to carbon and nutrient cycling in the ecosystems. In this study, we investigated litterfall and fine root biomass and production in five deciduous and four coniferous forests at the Gwangneung Experimental Forest in Korea. We used ingrowth cores to measure fine root production and root turnover rate. The litterfall was separated into leaves, twigs, and others, and then leaves were further separated according to species. Annual litterfall mass was not significantly different between the years, 360 to 651 g m-2 in 2011 and 300 to 656 g m-2 in 2012. Annual fine root (<5 mm) production was significantly higher in 2012 (421 to 1342 g m-2) than in 2011 (99 to 872 g m-2). Annual litterfall mass was significantly different among the stands, while fine root production did not statistically differ among the stands. The average fine root turnover rate, calculated by dividing the annual fine root production by the maximum standing fine root biomass, was 1.65 for deciduous forests and 1.97 for coniferous forests. Fine root production constituted 18–44% of NPP, where NPP was the sum of woody biomass production, litterfall production, and fine root production. Belowground production was a greater fraction of NPP in more productive forests suggesting their greater carbon allocation belowground. PMID:28662215

  6. Litterfall production and fine root dynamics in cool-temperate forests.

    PubMed

    An, Ji Young; Park, Byung Bae; Chun, Jung Hwa; Osawa, Akira

    2017-01-01

    Current understanding of litterfall and fine root dynamics in temperate forests is limited, even though these are the major contributors to carbon and nutrient cycling in the ecosystems. In this study, we investigated litterfall and fine root biomass and production in five deciduous and four coniferous forests at the Gwangneung Experimental Forest in Korea. We used ingrowth cores to measure fine root production and root turnover rate. The litterfall was separated into leaves, twigs, and others, and then leaves were further separated according to species. Annual litterfall mass was not significantly different between the years, 360 to 651 g m-2 in 2011 and 300 to 656 g m-2 in 2012. Annual fine root (<5 mm) production was significantly higher in 2012 (421 to 1342 g m-2) than in 2011 (99 to 872 g m-2). Annual litterfall mass was significantly different among the stands, while fine root production did not statistically differ among the stands. The average fine root turnover rate, calculated by dividing the annual fine root production by the maximum standing fine root biomass, was 1.65 for deciduous forests and 1.97 for coniferous forests. Fine root production constituted 18-44% of NPP, where NPP was the sum of woody biomass production, litterfall production, and fine root production. Belowground production was a greater fraction of NPP in more productive forests suggesting their greater carbon allocation belowground.

  7. Transport of fine sediment over a coarse, immobile riverbed

    USGS Publications Warehouse

    Grams, Paul E.; Wilcock, Peter R.

    2014-01-01

    Sediment transport in cobble-boulder rivers consists mostly of fine sediment moving over a coarse, immobile bed. Transport rate depends on several interrelated factors: boundary shear stress, the grain size and volume of fine sediment, and the configuration of fine sediment into interstitial deposits and bed forms. Existing models do not incorporate all of these factors. Approaches that partition stress face a daunting challenge because most of the boundary shear is exerted on immobile grains. We present an alternative approach that divides the bed into sand patches and interstitial deposits and is well constrained by two clear end-member cases: full sand cover and absence of sand. Entrainment from sand patches is a function of their aerial coverage. Entrainment from interstices among immobile grains is a function of sand elevation relative to the size of the immobile grains. The bed-sand coverage function is used to predict the ratio of the rate of entrainment from a partially covered bed to the rate of entrainment from a completely sand-covered bed, which is determined using a standard sand transport model. We implement the bed-sand coverage function in a morphodynamic routing model and test it against observations of sand bed elevation and suspended sand concentration for conditions of nonuniform fine sediment transport in a large flume with steady uniform flow over immobile hemispheres. The results suggest that this approach may provide a simple and robust method for predicting the transport and migration of fine sediment through rivers with coarse, immobile beds.

  8. Bridging the Digital Divide--An Australian Story

    ERIC Educational Resources Information Center

    Broadbent, Robyn; Papadopoulos, Theo

    2013-01-01

    There is increasing evidence that the lack of access to information and communication technology (ICT) or the "digital divide" severely limits education, employment and economic prospects. This paper reports on the evaluation of a project that aims to bridge the digital divide. In particular, the case study data has been used to bring to…

  9. Technology and the Cultural Divide: A Review of the Literature.

    ERIC Educational Resources Information Center

    Grant, Allen C.

    The recent proliferation of technology in educational settings is giving teachers new and innovative methods of teaching an inquiry-based curriculum within a constructivist framework. One problem within the nation's schools is the growing cultural divide. The cultural divide is the extent of the cultural barrier that exists between educators and…

  10. A Divided Attention Experiment with Pervasively Hyperactive Children.

    ERIC Educational Resources Information Center

    van der Meere, Jaap; Sergeant, Joseph

    1987-01-01

    Task performance of 12 pervasive hyperactives and controls (ages 8-13) was studied in a divided attention reaction time experiment. Hyperactives were slower than controls, had more variable reaction times, and made more frequent errors. Task inefficiency in hyperactives could not be explained by a divided attention deficiency or impulsive…

  11. Digital Natives and Digital Divide: Analysing Perspective for Emerging Pedagogy

    ERIC Educational Resources Information Center

    Onye, Uriel U.; Du, Yunfei

    2016-01-01

    This paper addresses the concepts of digital natives and digital divide from the perspective of the digital outsiders (part of digital natives). It takes a critical look at the implications of available ICT in both developed and underdeveloped countries in the fight against digital divide. The major contribution to literature is by drawing…

  12. 5 CFR 838.303 - Expressly dividing employee annuity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REGULATIONS (CONTINUED) COURT ORDERS AFFECTING RETIREMENT BENEFITS Requirements for Court Orders Affecting Employee Annuities § 838.303 Expressly dividing employee annuity. (a) A court order directed at employee annuity is not a court order acceptable for processing unless it expressly divides the employee annuity as...

  13. 5 CFR 838.303 - Expressly dividing employee annuity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REGULATIONS (CONTINUED) COURT ORDERS AFFECTING RETIREMENT BENEFITS Requirements for Court Orders Affecting Employee Annuities § 838.303 Expressly dividing employee annuity. (a) A court order directed at employee annuity is not a court order acceptable for processing unless it expressly divides the employee annuity as...

  14. 5 CFR 838.303 - Expressly dividing employee annuity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS (CONTINUED) COURT ORDERS AFFECTING RETIREMENT BENEFITS Requirements for Court Orders Affecting Employee Annuities § 838.303 Expressly dividing employee annuity. (a) A court order directed at employee annuity is not a court order acceptable for processing unless it expressly divides the employee annuity as...

  15. Confronting the Digital Divide: Debunking Brave New World Discourses

    ERIC Educational Resources Information Center

    Rowsell, Jennifer; Morrell, Ernest; Alvermann, Donna E.

    There is far more to the digital divide than meets the eye. In this article, the authors consolidate existing research on the digital divide to offer some tangible ways for educators to bridge the gap between the haves and have-nots, or the cans and cannots. Drawing on Aldous Huxley's notion of a "brave new world," some digital divide…

  16. The Digital Divide and Health Outcomes: A Teleretinal Imaging Study

    ERIC Educational Resources Information Center

    Connolly, Kathleen Kihmm

    2013-01-01

    The purpose of this research project was to understand, explore and describe the digital divide and the relationship between technology utilization and health outcomes. Diabetes and diabetic eye disease was used as the real-life context for understanding change and exploring the digital divide. As an investigational framework, a telemedicine…

  17. Distance Education and the Digital Divide: An Academic Perspective

    ERIC Educational Resources Information Center

    Block, Judy

    2010-01-01

    This paper will address how the digital divide affects distance education. Lack of access for some students does raise concerns. Access to technology is often defined by what students don't have: what is called a digital divide. Access also is defined by the speed of Internet connections. Access in the future will be even greater as more computers…

  18. Negotiating Digital Divides: Perspectives from the New Zealand Schooling System

    ERIC Educational Resources Information Center

    Starkey, Louise; Sylvester, Allan; Johnstone, David

    2017-01-01

    This article explores digital divides identified in research literature and considers educational policy directions that may mitigate or enhance future inequities. A review of literature identified three categories of digital divides in society; access, capability, and participation. To explore the strategic focus in schooling, data were gathered…

  19. 37 CFR 2.87 - Dividing an application.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Dividing an application. 2.87 Section 2.87 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Classification § 2.87 Dividing an application. (a...

  20. The Digital Divide and Health Outcomes: A Teleretinal Imaging Study

    ERIC Educational Resources Information Center

    Connolly, Kathleen Kihmm

    2013-01-01

    The purpose of this research project was to understand, explore and describe the digital divide and the relationship between technology utilization and health outcomes. Diabetes and diabetic eye disease was used as the real-life context for understanding change and exploring the digital divide. As an investigational framework, a telemedicine…

  1. Rethinking the Digital Divide: Impacts on Student-Tutor Relationships

    ERIC Educational Resources Information Center

    Underwood, Jean D. M.

    2007-01-01

    This article emerged from a series of debates and workshops on the impact of the Digital Divide on educational practice at the "Futures of Learning: New Learning Paradigms Conference" in Paris. The conceptualisation of the Digital Divide into the "haves" and the "have-nots", with a perception of the economically…

  2. Distance Education and the Digital Divide: An Academic Perspective

    ERIC Educational Resources Information Center

    Block, Judy

    2010-01-01

    This paper will address how the digital divide affects distance education. Lack of access for some students does raise concerns. Access to technology is often defined by what students don't have: what is called a digital divide. Access also is defined by the speed of Internet connections. Access in the future will be even greater as more computers…

  3. Bridging the Digital Divide--An Australian Story

    ERIC Educational Resources Information Center

    Broadbent, Robyn; Papadopoulos, Theo

    2013-01-01

    There is increasing evidence that the lack of access to information and communication technology (ICT) or the "digital divide" severely limits education, employment and economic prospects. This paper reports on the evaluation of a project that aims to bridge the digital divide. In particular, the case study data has been used to bring to…

  4. 37 CFR 2.87 - Dividing an application.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... application. (c) Time for filing. (1) A request to divide an application may be filed at any time between the... Trademark Trial and Appeal Board. (2) In an application under section 1(b) of the Act, a request to divide may also be filed with a statement of use under § 2.88 or at any time between the filing of a...

  5. X-Band Strip-Line Power Divider/Combiner

    NASA Technical Reports Server (NTRS)

    Conroy, B. L.

    1985-01-01

    Strip-line circuit for X-band signals both divides and combines microwave power for distributed amplifier. Strip-line pattern (foil pattern over insulating layer over ground plane) laid out so all eight distributed ports lie at electrical distances of odd integral multiples of half wavelength from main input/output port. Strip line used as power divider and as power combiner.

  6. Evaluation of Fatih Project in the Frame of Digital Divide

    ERIC Educational Resources Information Center

    Karabacak, Kerim

    2016-01-01

    The aim of this research realized at the general survey model is to evaluate "FATIH Project" in the frame of digital divide by determining the effects of the distributed tablets to the students being educated at K-12 schools on digital divide. Sample is taking from the 9th grade students in Sakarya city in the 2013-2014 academic session.…

  7. The Digital Divide in Health Education: Myth or Reality?

    ERIC Educational Resources Information Center

    Stellefson, Michael; Chaney, Beth; Chaney, Don

    2008-01-01

    Although e-health interventions provide new opportunities for health education, there has been cause for concern regarding the purported information technology gap between those who have access to digital applications and those who do not--termed the "digital divide." The literature suggests, however, that this divide may now be illusory, driven…

  8. Prospective memory: effects of divided attention on spontaneous retrieval.

    PubMed

    Harrison, Tyler L; Mullet, Hillary G; Whiffen, Katie N; Ousterhout, Hunter; Einstein, Gilles O

    2014-02-01

    We examined the effects of divided attention on the spontaneous retrieval of a prospective memory intention. Participants performed an ongoing lexical decision task with an embedded prospective memory demand, and also performed a divided-attention task during some segments of lexical decision trials. In all experiments, monitoring was highly discouraged, and we observed no evidence that participants engaged monitoring processes. In Experiment 1, performing a moderately demanding divided-attention task (a digit detection task) did not affect prospective memory performance. In Experiment 2, performing a more challenging divided-attention task (random number generation) impaired prospective memory. Experiment 3 showed that this impairment was eliminated when the prospective memory cue was perceptually salient. Taken together, the results indicate that spontaneous retrieval is not automatic and that challenging divided-attention tasks interfere with spontaneous retrieval and not with the execution of a retrieved intention.

  9. Technique for extending the frequency range of digital dividers

    NASA Technical Reports Server (NTRS)

    Long, W. C.; Middleton, J. H. (Inventor)

    1973-01-01

    A technique for extending the frequency range of a presettable digital divider is described. The conventional digital divider consists of several counter stages with the count of each stage compared to a preselected number. When the counts for all stages are equal to the preselected numbers, an output pulse is generated and all stages are reset. For high input frequencies, the least significant stage of the divider has to be reset in a very short time. This limits the frequency that can be handled by the conventional digital divider. This invention provides a technique in which the second least significant and higher stages are reset and the least significant stage is permitted to free-run. Hence, the time in which the reset operation can be performed is increased thereby extending the frequency range of the divider.

  10. [Design of broadband power divider in microwave hyperthermia system].

    PubMed

    Sun, Bing; Jiang, Guotai; Lu, Xiaofeng; Cao, Yi

    2010-10-01

    In clinical application of microwave hyperthermia, multi-applicators are often simultaneously required to irradiate the tumor because of its large volume or its deep location. Power divider separates the input microwave energy into equal, or unequal, energy to each applicator. In this paper, the design procedure for the three-section transmission-line transformer based one-to-two equal-split Wilkinson power divider is introduced. By impedance analysis on equivalent scheme, the design parameter of power divider is provided, and by simulation and optimization on Ansoft HFSS, a microstrip structure Wilkinson power divider operating frequency 2. 45 GHz is given. Measurement test results from network analyzer show that it has 25% bandwidth and good isolation in output with this structure. Besides, it is characterized by small size and easy processing. This power divider suits microwave hyperthermia.

  11. Dividing attention lowers children's but increases adults' false memories.

    PubMed

    Otgaar, Henry; Peters, Maarten; Howe, Mark L

    2012-01-01

    The present study examined the impact of divided attention on children's and adults' neutral and negative true and false memories in a standard Deese/Roediger-McDermott paradigm. Children (7- and 11-year-olds; n = 126) and adults (n = 52) received 5 neutral and 5 negative Deese/Roediger-McDermott word lists; half of each group also received a divided attention task. The results showed that divided attention affected children's and adults' false memory levels differently but did not alter true memory differently. Our results revealed a developmental shift in that divided attention lowered children's false memory rates but increased adults' false memory rates, regardless of the nature of the material (i.e., neutral or negative). Our study indicates that manipulations that target conscious processing (e.g., divided attention) result in marked qualitative and quantitative differences between children's and adults' false memories but not true memories.

  12. Three-dimensional multiway power dividers based on transformation optics

    PubMed Central

    Wu, Yong-Le; Zhuang, Zheng; Deng, Li; Liu, Yuan-An

    2016-01-01

    The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers. PMID:27091541

  13. Hydrogenation of succinic acid to 1,4-butanediol over rhenium catalyst supported on copper-containing mesoporous carbon.

    PubMed

    Hong, Ung Gi; Park, Hai Woong; Lee, Joongwon; Hwang, Sunhwan; Kwak, Jimin; Yi, Jongheop; Song, In Kyu

    2013-11-01

    Copper-containing mesoporous carbon (Cu-MC) was prepared by a single-step surfactant-templating method. For comparison, copper-impregnated mesoporous carbon (Cu/MC) was also prepared by a surfactant-templating method and a subsequent impregnation method. Rhenium catalysts supported on copper-containing mesoporous carbon and copper-impregnated mesoporous carbon (Re/Cu-MC and Re/Cu/MC, respectively) were then prepared by an incipient wetness method, and they were applied to the liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO). It was observed that copper in the Re/Cu-MC catalyst was well incorporated into carbon framework, resulting in higher surface area and larger pore volume than those of Re/Cu/MC catalyst. Therefore, Re/Cu-MC catalyst showed higher copper dispersion than Re/Cu/MC catalyst, although both catalysts retained the same amounts of copper and rhenium. In the liquid-phase hydrogenation of succinic acid to BDO, Re/Cu-MC catalyst showed a better catalytic activity than Re/Cu/MC catalyst. Fine dispersion of copper in the Re/Cu-MC catalyst was responsible for its enhanced catalytic activity.

  14. Stereospecific olefin polymerization catalysts

    DOEpatents

    Bercaw, John E.; Herzog, Timothy A.

    1998-01-01

    A metallocene catalyst system for the polymerization of .alpha.-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula ##STR1## wherein: R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group consisting of hydrogen, C.sub.1 to C.sub.10 alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C.sub.1 to C.sub.10 alkyls as a substituent, C.sub.6 to C.sub.15 aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R.sup.8).sub.3 where R.sup.8 is selected from the group consisting of C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; R.sup.4 and R.sup.6 are substituents both having van der Waals radii larger than the van der Waals radii of groups R.sup.1 and R.sup.3 ; R.sup.5 is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E.sup.1, E.sup.2 are independently selected from the group consisting of Si(R.sup.9).sub.2, Si(R.sup.9).sub.2 --Si(R.sup.9).sub.2, Ge(R.sup.9).sub.2, Sn(R.sup.9).sub.2, C(R.sup.9).sub.2, C(R.sup.9).sub.2 --C(R.sup.9).sub.2, where R.sup.9 is C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; and the ligand may have C.sub.S or C.sub.1 -symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from .alpha.-olefin monomers.

  15. Stereospecific olefin polymerization catalysts

    DOEpatents

    Bercaw, J.E.; Herzog, T.A.

    1998-01-13

    A metallocene catalyst system is described for the polymerization of {alpha}-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula shown wherein: R{sup 1}, R{sup 2}, and R{sup 3} are independently selected from the group consisting of hydrogen, C{sub 1} to C{sub 10} alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C{sub 1} to C{sub 10} alkyls as a substituent, C{sub 6} to C{sub 15} aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R{sup 8}){sub 3} where R{sup 8} is selected from the group consisting of C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; R{sup 4} and R{sup 6} are substituents both having van der Waals radii larger than the van der Waals radii of groups R{sup 1} and R{sup 3}; R{sup 5} is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E{sup 1}, E{sup 2} are independently selected from the group consisting of Si(R{sup 9}){sub 2}, Si(R{sup 9}){sub 2}--Si(R{sup 9}){sub 2}, Ge(R{sup 9}){sub 2}, Sn(R{sup 9}){sub 2}, C(R{sup 9}){sub 2}, C(R{sup 9}){sub 2}--C(R{sup 9}){sub 2}, where R{sup 9} is C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; and the ligand may have C{sub S} or C{sub 1}-symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from {alpha}-olefin monomers.

  16. Monitoring pool-tail fines

    NASA Astrophysics Data System (ADS)

    Bunte, K.; Potyondy, J. P.; Abt, S. R.; Swingle, K. W.

    2010-12-01

    Fine sediment < 2 and < 6 mm deposited in pool-tail areas of mountain streams is often measured to monitor changes in the supply of fines (e.g., by dam removal, bank erosion, or watershed effects including fires and road building) or to assess the status and trend of aquatic ecosystems. Grid counts, pebble counts, and volumetric bedmaterial samples are typically used to quantify pool-tail fines. Grid-count results exhibit a high degree of variability not only among streams and among operators, but also among crews performing a nearly identical procedure (Roper et al. 2010). Variability is even larger when diverse methods are employed, each of which quantifies fines in a different way: grid counts visually count surface fines on small patches within the pool-tail area, pebble counts pick up and tally surface particles along (riffle) transects, and volumetric samples sieve out fines from small-scale bulk samples; and even when delimited to pool-tail areas, individual methods focus on different sampling locales. Two main questions were analyzed: 1) Do pool-tail fines exhibit patterns of spatial variability and are some grid count schemes more likely to provide accurate results than others. 2) How and why does the percentage of fines vary among grid counts, pebble counts, and volumetric samples. In a field study, grids were placed at 7 locales in two rows across the wetted width of 10 pool tails in a 14-m wide 3rd order coarse gravel-bed mountain stream with <4% sand and <8% < 6 mm. Several pebble count transects were placed across each pool-tail area, and three volumetric samples were collected in each of three pool tails. Pebble and grid counts both indicated a fining trend towards one or both banks, sometimes interrupted by a secondary peak of fines within the central half of the wetted width. Among the five sampling schemes tested, grid counts covering the wetted width with 7 locales produced the highest accuracy and the least variability among the pools of the

  17. Catalytic cracking catalysts

    SciTech Connect

    Chiang, R.L.; Perigard, R.G.; Rabo, J.A.

    1986-05-13

    A process is described for preparing a catalyst comprising the following steps: (i) contacting a mixture of a large pore zeolite and an inorganic oxide matrix, with a fluoro salt of the formula A/sub (n-m)/(MF/sub n/)/sub z/ wherein ''A'' is an organic or inorganic ionic moiety; (MF/sub n/)/sub z/ is a fluoroanion moiety comprising the element ''M''; ''M'' is an element selected from the group of elements from Groups VB, VIB, VIIB, VIII, IIIA, IVA and VA of the Periodic Table of Elements; ''n'' is the coordination number of ''M''; ''m'' is the valence of ''M''; and ''z'' is the valence or charge associated with ''A''; at a pH greater than about 3, at effective conditions of temperature and time.

  18. Catalyst deactivation in residue hydrocracking

    SciTech Connect

    Oballa, M.C.; Wong, C.; Krzywicki, A.

    1994-12-31

    The existence of a computer-controlled bench scale hydrocracking units at the authors site has made cheaper the non-stop running of experiments for long periods of time. It was, therefore possible to show, at minimal costs, when three hydrocracking catalysts in service reach their maximum lifetime. Different parameters which are helpful for catalyst life and activity predictions were calculated, e.g., relative catalyst age and the effectiveness factor. Experimental results compared well with model, giving them the minimum and maximum catalyst lifetime, as well as the deactivation profile with regard to sulfur and metals removal. Reaction rate constants for demetallization and desulfurization were also determined. Six commercial catalysts were evaluated at short term runs and the three most active were used for long term runs. Out of three catalysts tested for deactivation at long term runs, it was possible to choose one whose useful life was higher than the others. All runs were carried out in a Robinson-Mahoney continuous flow stirred tank reactor, using 50/50 volumetric mixture of Cold Lake/Lloydminster atmospheric residue and NiMo/Al{sub 2}O{sub 3} catalyst.

  19. Ceramic catalyst materials

    SciTech Connect

    Sault, A.G.; Gardner, T.J.; Hanprasopwattanna, A.; Reardon, J.; Datye, A.K.

    1995-08-01

    Hydrous titanium oxide (HTO) ion-exchange materials show great potential as ceramic catalyst supports due to an inherently high ion-exchange capacity which allows facile loading of catalytically active transition metal ions, and an ability to be cast as thin films on virtually any substrate. By coating titania and HTO materials onto inexpensive, high surface area substrates such as silica and alumina, the economics of using these materials is greatly improved, particularly for the HTO materials, which are substantially more expensive in the bulk form than other oxide supports. In addition, the development of thin film forms of these materials allows the catalytic and mechanical properties of the final catalyst formulation to be separately engineered. In order to fully realize the potential of thin film forms of titania and HTO, improved methods for the deposition and characterization of titania and HTO films on high surface area substrates are being developed. By varying deposition procedures, titania film thickness and substrate coverage can be varied from the submonolayer range to multilayer thicknesses on both silica and alumina. HTO films can also be formed, but the quality and reproducibility of these films is not nearly as good as for pure titania films. The films are characterized using a combination of isopropanol dehydration rate measurements, point of zero charge (PZC) measurements, BET surface area, transmission electron microscopy (TEM), and elemental analysis. In order to assess the effects of changes in film morphology on catalytic activity, the films are being loaded with MoO{sub 3} using either incipient wetness impregnation or ion-exchange of heptamolybdate anions followed by calcining. The MoO{sub 3} is then sulfided to form MOS{sub 2}, and tested for catalytic activity using pyrene hydrogenation and dibenzothiophene (DBT) desulfurization, model reactions that simulate reactions occurring during coal liquefaction.

  20. Development of GREET Catalyst Module

    SciTech Connect

    Wang, Zhichao; Dunn, Jennifer B.; Cronauer, Donald C.

    2014-09-01

    Catalysts are critical inputs for many pathways that convert biomass into biofuels. Energy consumption and greenhouse gas (GHG) emissions during the production of catalysts and chemical inputs influence the life-cycle energy consumption, and GHG emissions of biofuels and need to be considered in biofuel life-cycle analysis (LCA). In this report, we develop energy and material flows for the production of three different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5]) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module. They were selected because they are consumed in existing U.S. Department of Energy (DOE) analyses of biofuel processes. For example, a thermochemical ethanol production pathway (indirect gasification and mixed alcohol synthesis) developed by the National Renewable Energy Laboratory (NREL) uses olivine, DEPG, and tar reforming and alcohol synthesis catalysts (Dutta et al., 2011). ZSM-5 can be used in biofuel production pathways such as catalytic upgrading of sugars into hydrocarbons (Biddy and Jones, 2013). Other uses for these compounds and catalysts are certainly possible. In this report, we document the data sources and methodology we used to develop material and energy flows for the catalysts and compounds in the GREET catalyst module. In Section 2 we focus on compounds used in the model Dutta et al. (2011) developed. In Section 3, we report material and energy flows associated with ZSM-5 production. Finally, in Section 4, we report results.

  1. Biofilms as living catalysts in continuous chemical syntheses.

    PubMed

    Halan, Babu; Buehler, Katja; Schmid, Andreas

    2012-09-01

    Biofilms are resilient to a wide variety of environmental stresses. This inherited robustness has been exploited mainly for bioremediation. With a better understanding of their physiology, the application of these living catalysts has been extended to the production of bulk and fine chemicals as well as towards biofuels, biohydrogen, and electricity production in microbial fuel cells. Numerous challenges call for novel solutions and concepts of analytics, biofilm reactor design, product recovery, and scale-up strategies. In this review, we highlight recent advancements in spatiotemporal biofilm characterization and new biofilm reactor developments for the production of value-added fine chemicals as well as current challenges and future scenarios. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Chalcogen catalysts for polymer electrolyte fuel cell

    DOEpatents

    Zelenay, Piotr; Choi, Jong-Ho; Alonso-Vante, Nicolas; Wieckowski, Andrzej; Cao, Dianxue

    2010-08-24

    A methanol-tolerant cathode catalyst and a membrane electrode assembly for fuel cells that includes such a cathode catalyst. The cathode catalyst includes a support having at least one transition metal in elemental form and a chalcogen disposed on the support. Methods of making the cathode catalyst and membrane electrode assembly are also described.

  3. Chalcogen catalysts for polymer electrolyte fuel cell

    DOEpatents

    Alonso-Vante, Nicolas [Buxerolles, FR; Zelenay, Piotr [Los Alamos, NM; Choi, Jong-Ho [Los Alamos, NM; Wieckowski, Andrzej [Champaign, IL; Cao, Dianxue [Urbana, IL

    2009-09-15

    A methanol-tolerant cathode catalyst and a membrane electrode assembly for fuel cells that includes such a cathode catalyst. The cathode catalyst includes a support having at least one transition metal in elemental form and a chalcogen disposed on the support. Methods of making the cathode catalyst and membrane electrode assembly are also described.

  4. Green chemistry: Biodiesel made with sugar catalyst

    NASA Astrophysics Data System (ADS)

    Toda, Masakazu; Takagaki, Atsushi; Okamura, Mai; Kondo, Junko N.; Hayashi, Shigenobu; Domen, Kazunari; Hara, Michikazu

    2005-11-01

    The production of diesel from vegetable oil calls for an efficient solid catalyst to make the process fully ecologically friendly. Here we describe the preparation of such a catalyst from common, inexpensive sugars. This high-performance catalyst, which consists of stable sulphonated amorphous carbon, is recyclable and its activity markedly exceeds that of other solid acid catalysts tested for `biodiesel' production.

  5. ZSM-5 catalyst developed for toluene disproportionation

    SciTech Connect

    Han, S.; Shihabi, D.S. ); Absil, R.P.L.; Huang, Y.Y.; Leiby, S.M.; Marler, D.O.; McWilliams, J.P. )

    1989-08-21

    Toluene disproportionation over a new ZSM-5 catalyst formulation shows better activity and stability compared to the current Mobil Toluene disproportionation (MTDP) catalyst. Subsequent adiabatic pilot plant operations confirmed the activity and stability of the new catalyst. This process flexibility is expected to translate into considerable economic advantages for the process using the new catalyst formulation.

  6. Textured catalysts, methods of making textured catalysts, and methods of catalyzing reactions conducted in hydrothermal conditions

    DOEpatents

    Werpy, Todd [West Richland, WA; Wang, Yong [Richland, WA

    2003-12-30

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  7. Molecular metal catalysts on supports: organometallic chemistry meets surface science.

    PubMed

    Serna, Pedro; Gates, Bruce C

    2014-08-19

    Recent advances in the synthesis and characterization of small, essentially molecular metal complexes and metal clusters on support surfaces have brought new insights to catalysis and point the way to systematic catalyst design. We summarize recent work unraveling effects of key design variables of site-isolated catalysts: the metal, metal nuclearity, support, and other ligands on the metals, also considering catalysts with separate, complementary functions on supports. The catalysts were synthesized with the goal of structural simplicity and uniformity to facilitate incisive characterization. Thus, they are essentially molecular species bonded to porous supports chosen for their high degree of uniformity; the supports are crystalline aluminosilicates (zeolites) and MgO. The catalytic species are synthesized in reactions of organometallic precursors with the support surfaces; the precursors include M(L)2(acetylacetonate)1-2, with M = Ru, Rh, Ir, or Au and the ligands L = C2H4, CO, or CH3. Os3(CO)12 and Ir4(CO)12 are used as precursors of supported metal clusters, and some such catalysts are made by ship-in-a-bottle syntheses to trap the clusters in zeolite cages. The simplicity and uniformity of the supported catalysts facilitate precise structure determinations, even in reactive atmospheres and during catalysis. The methods of characterizing catalysts in reactive atmospheres include infrared (IR), extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and nuclear magnetic resonance (NMR) spectroscopies, and complementary methods include density functional theory and atomic-resolution aberration-corrected scanning transmission electron microscopy for imaging of individual metal atoms. IR, NMR, XANES, and microscopy data demonstrate the high degrees of uniformity of well-prepared supported species. The characterizations determine the compositions of surface metal complexes and clusters, including the ligands and the metal

  8. High Temperature Membrane & Advanced Cathode Catalyst Development

    SciTech Connect

    Protsailo, Lesia

    2006-04-20

    Current project consisted of three main phases and eighteen milestones. Short description of each phase is given below. Table 1 lists program milestones. Phase 1--High Temperature Membrane and Advanced Catalyst Development. New polymers and advanced cathode catalysts were synthesized. The membranes and the catalysts were characterized and compared against specifications that are based on DOE program requirements. The best-in-class membranes and catalysts were downselected for phase 2. Phase 2--Catalyst Coated Membrane (CCM) Fabrication and Testing. Laboratory scale catalyst coated membranes (CCMs) were fabricated and tested using the down-selected membranes and catalysts. The catalysts and high temperature membrane CCMs were tested and optimized. Phase 3--Multi-cell stack fabrication. Full-size CCMs with the down-selected and optimized high temperature membrane and catalyst were fabricated. The catalyst membrane assemblies were tested in full size cells and multi-cell stack.

  9. Geology of photo linear elements, Great Divide Basin, Wyoming

    NASA Technical Reports Server (NTRS)

    Blackstone, D. L., Jr.

    1973-01-01

    The author has identified the following significant results. Ground examination of photo linear elements in the Great Divide Basin, Wyoming indicates little if any tectonic control. Aeolian aspects are more widespread and pervasive than previously considered.

  10. Evaluation of the divided attention condition during functional analyses.

    PubMed

    Fahmie, Tara A; Iwata, Brian A; Harper, Jill M; Querim, Angie C

    2013-01-01

    A common condition included in most functional analyses (FAs) is the attention condition, in which the therapist ignores the client by engaging in a solitary activity (antecedent event) but delivers attention to the client contingent on problem behavior (consequent event). The divided attention condition is similar, except that the antecedent event consists of the therapist conversing with an adult confederate. We compared the typical and divided attention conditions to determine whether behavior in general (Study 1) and problem behavior in particular (Study 2) were more sensitive to one of the test conditions. Results showed that the divided attention condition resulted in faster acquisition or more efficient FA results for 2 of 9 subjects, suggesting that the divided attention condition could be considered a preferred condition when resources are available.

  11. Divided attention: an undesirable difficulty in memory retention.

    PubMed

    Gaspelin, Nicholas; Ruthruff, Eric; Pashler, Harold

    2013-10-01

    How can we improve memory retention? A large body of research has suggested that difficulty encountered during learning, such as when practice sessions are distributed rather than massed, can enhance later memory performance (see R. A. Bjork & E. L. Bjork, 1992). Here, we investigated whether divided attention during retrieval practice can also constitute a desirable difficulty. Following two initial study phases and one test phase with Swahili-English word pairs (e.g., vuvi-snake), we manipulated whether items were tested again under full or divided attention. Two days later, participants were brought back for a final cued-recall test (e.g., vuvi-?). Across three experiments (combined N = 122), we found no evidence that dividing attention while practicing retrieval enhances memory retention. This finding raises the question of why many types of difficulty during practice do improve long-term retention, but dividing attention does not.

  12. A 83 GHz InP DHBT static frequency divider

    NASA Astrophysics Data System (ADS)

    Youtao, Zhang; Xiaopeng, Li; Min, Zhang; Wei, Cheng; Xinyu, Chen

    2014-04-01

    A static frequency divider is presented using 0.7 μm InP DHBTs with 280 GHz ft/fmax. The divider is based on ECL master-slave D-flip-flop topology with 30 HBTs and 20 resistors with a chip size 0.62 × 0.65 mm2. The circuits use peaking inductance as a part of the loads to maximize the highest clock rate. Momentum simulation is used to accurately characterize the effect of the clock feedback lines at the W band. Test results show that the divider can operate from 1 GHz up to 83 GHz. Its phase noise is 139 dBc/Hz with 100 kHz offset. The power dissipation of divider core is 350 mW.

  13. 222. NORTH END OF DIVIDING STRIP LOCATED NEAR LITTLE HUNTING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    222. NORTH END OF DIVIDING STRIP LOCATED NEAR LITTLE HUNTING CREEK ON GWMP LOOKING SOUTH, 1946. - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

  14. An improved fractional divider for fractional-N frequency synthesizers

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Liu, Yang; Zhou, Yongqi

    2009-07-01

    This paper presents an improved fractional divider used in 1.8~2GHz fractional-N frequency synthesizers. A new clock setting for delta-sigma modulator (DSM) is proposed to prevent the potential problems of traditional fractional dividers: the DSM output would be wrongly loaded and the action of DSM circuit may affect the phase-detection of phase-frequency-detector (PFD). Simulation result shows the effectiveness of this improvement.

  15. Coarse-fine adaptive tuned vibration absorber with high frequency resolution

    NASA Astrophysics Data System (ADS)

    Wang, Xi; Yang, Bintang; You, Jiaxin; Gao, Zhe

    2016-11-01

    The speed fluctuation of satellite-rotary-mechanisms causes vibration of slightly different frequencies. The critical requirements of satellites need a vibration control device with high frequency resolution to suppress the vibration. This paper presents a coarse-fine adaptive tuned vibration absorber (ATVA) with high frequency resolution. The coarse-fine ATVA which simultaneously satisfies the requirements of high resolution and relatively wide effective bandwidth is capable of tracking the variable exciting frequency adaptively to suppress the vibration of the primary system. The coarse-fine ATVA is divided into a coarse tuning segment and a fine tuning segment. The coarse tuning segment is used to tune the required natural frequency in a relatively wide effective bandwidth and the fine tuning segment can achieve precise tune in a tiny-scale bandwidth. The mathematical model of the coarse tuning and the fine tuning is proposed to design the parameters of the coarse-fine ATVA. The experimental test results indicate the coarse tuning bandwidth of the coarse-fine ATVA is 8.7 Hz to 29 Hz and the minimum resolution of the fine tuning is 0.05 Hz. Moreover, a significant vibration attenuation of 15dB is verified in the effective bandwidth.

  16. The contribution of working memory to divided attention.

    PubMed

    Santangelo, Valerio; Macaluso, Emiliano

    2013-01-01

    Previous studies have indicated that increasing working memory (WM) load can affect the attentional selection of signals originating from one object/location. Here we assessed whether WM load affects also the selection of multiple objects/locations (divided attention). Participants monitored either two object-categories (vs. one category; object-based divided attention) or two locations (vs. one location; space-based divided attention) while maintaining in WM either a variable number of objects (object-based WM load) or locations (space-based WM load). Behavioural results showed that WM load affected attentional performance irrespective of divided or focused attention. However, fMRI results showed that the activity associated with object-based divided attention increased linearly with increasing object-based WM load in the left and right intraparietal sulcus (IPS); while, in the same areas, activity associated with space-based divided attention was not affected by any type of WM load. These findings support the hypothesis that WM contributes to the maintenance of resource-demanding attentional sets in a domain-specific manner. Moreover, the dissociable impact of WM load on performance and brain activity suggests that increased IPS activation reflects a recruitment of additional, domain-specific processing resources that enable dual-task performance under conditions of high WM load and high attentional demand.

  17. Bifunctional Organic Polymeric Catalysts with a Tunable Acid-Base Distance and Framework Flexibility

    PubMed Central

    Chen, Huanhui; Wang, Yanan; Wang, Qunlong; Li, Junhui; Yang, Shiqi; Zhu, Zhirong

    2014-01-01

    Acid-base bifunctional organic polymeric catalysts were synthesized with tunable structures. we demonstrated two synthesis approaches for structural fine-tune. In the first case, the framework flexibility was tuned by changing the ratio of rigid blocks to flexible blocks within the polymer framework. In the second case, we precisely adjusted the acid-base distance by distributing basic monomers to be adjacent to acidic monomers, and by changing the chain length of acidic monomers. In a standard test reaction for the aldol condensation of 4-nitrobenzaldehyde with acetone, the catalysts showed good reusability upon recycling and maintained relatively high conversion percentage. PMID:25267260

  18. Bifunctional Organic Polymeric Catalysts with a Tunable Acid-Base Distance and Framework Flexibility

    NASA Astrophysics Data System (ADS)

    Chen, Huanhui; Wang, Yanan; Wang, Qunlong; Li, Junhui; Yang, Shiqi; Zhu, Zhirong

    2014-09-01

    Acid-base bifunctional organic polymeric catalysts were synthesized with tunable structures. we demonstrated two synthesis approaches for structural fine-tune. In the first case, the framework flexibility was tuned by changing the ratio of rigid blocks to flexible blocks within the polymer framework. In the second case, we precisely adjusted the acid-base distance by distributing basic monomers to be adjacent to acidic monomers, and by changing the chain length of acidic monomers. In a standard test reaction for the aldol condensation of 4-nitrobenzaldehyde with acetone, the catalysts showed good reusability upon recycling and maintained relatively high conversion percentage.

  19. Catalyst for sodium chlorate decomposition

    NASA Technical Reports Server (NTRS)

    Wydeven, T.

    1972-01-01

    Production of oxygen by rapid decomposition of cobalt oxide and sodium chlorate mixture is discussed. Cobalt oxide serves as catalyst to accelerate reaction. Temperature conditions and chemical processes involved are described.

  20. Secret Lives of Catalysts Revealed

    ScienceCinema

    Miquel Salmeron and Gabor Somorjai

    2016-07-12

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-relea...

  1. Secret Lives of Catalysts Revealed

    SciTech Connect

    Miquel Salmeron and Gabor Somorjai

    2008-10-15

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-relea...

  2. 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.

  3. SEPARATION OF FISCHER-TROPSCH WAX PRODUCTS FROM ULTRAFINE IRON CATALYST PARTICLES

    SciTech Connect

    James K. Neathery; Gary Jacobs; Burtron H. Davis

    2004-09-30

    In this reporting period, a fundamental filtration study was continued to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. The overall focus of the program is with slurry-phase FTS in slurry bubble column reactor systems. Hydrocarbon products must be separated from catalyst particles before being removed from the reactor system. An efficient wax product/catalyst separation system is a key factor for optimizing operating costs for iron-based slurry-phase FTS. Previous work has focused on catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. With the current study, we are investigating how the filtration properties are affected by these chemical and physical changes of the catalyst slurry during activation/synthesis. The shakedown phase of the pilot-scale filtration platform was completed at the end of the last reporting period. A study of various molecular weight waxes was initiated to determine the effect of wax physical properties on the permeation rate without catalyst present. As expected, the permeation flux was inversely proportional to the nominal average molecular weight of the polyethylene wax. Even without catalyst particles present in the filtrate, the filtration membranes experience fouling during an induction period on the order of days on-line. Another long-term filtration test was initiated using a batch of iron catalyst that was previously activated with CO to form iron carbide in a separate continuous stirred tank reactor (CSTR) system. The permeation flux stabilized more rapidly than that experienced with unactivated catalyst tests.

  4. Separately supported polymetallic reforming catalyst

    SciTech Connect

    Kresge, C. T.; Krishnamurthy, S.; McHale, W. D.

    1985-01-15

    There is provided, in accordance with the present invention, a catalyst composition made up of a mixture of two components, one component comprising a minor proportion of platinum and rhenium on a support and the second component comprising a minor proportion of iridium and rhenium on a separate support. A process for reforming a charge stock, such as naphtha, utilizing such catalyst is also provided.

  5. Clay complexes support HDS catalyst.

    SciTech Connect

    Marshall, C. L.; Carrado, K.; Chemical Engineering

    2000-01-01

    Hydroprocessing represents a crucial component of petroleum refining operations both in terms of environmental and economic considerations. Regulations concerning maximum amount of sulfur content of gasoline and emissions of sulfur-oxide compounds upon combustion are becoming more and more stringent. One 1994-2000 focus of Argonne National Laboratory (ANL) has been the development of catalysts for hydrodesulfurization (HDS). Typical HDS catalysts are comprised of Co-Mo sulfides or Ni-Mo sulfides on an alumina support. Modification of the pore structure of the support has generated great attention among researchers. Most desulfurization test reactions have used dibenzothiophene (DBT) as the model compound to test various configurations of support material with Co-Mo-S and Ni-Mo-S catalysts. In this testing, the desired product would be biphenyl and hydrogen sulfide (H{sub 2}S). A competing reaction creates cyclohexylbenzene by saturating one aromatic ring prior to desulfurization. Ring saturation requires more costly hydrogen and is not desirable. Fortunately, a more effective catalyst for adding hydrogen at the sulfur site with hydrogenating the aromatic rings has been found. However, this has only been tested on DBT. HDS uses various types of catalysts to add hydrogen to reduce unwanted sulfur compounds. Typically this requires expensive, high-pressure, high-temperature equipment to produce the environmentally friendly low-sulfur fuels. ANL scientists identified several new desulfurization catalysts with improved HDS activity and selectivity. From these new catalysts, it may be possible to achieve HDS processing at lower temperature and pressure. The catalysts used for HDS at ANL are various clay complexes. Natural clays have a history of use in the hydroprocessing industry since they are abundant and inexpensive. ANL's approach is to create synthetic organo-clay complexes (SOCC). An advantage of SOCCs is that the pore size and distribution can be controlled by

  6. Catalyst for carbon monoxide oxidation

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T. (Inventor); Miller, Irvin M. (Inventor); Brown, David R. (Inventor); Davis, Patricia (Inventor); Schryer, David R. (Inventor); Brown, Kenneth G. (Inventor); Vannorman, John D. (Inventor)

    1990-01-01

    A catalyst is disclosed for the combination of CO and O2 to form CO2, which includes a platinum group metal (e.g., platinum); a reducable metal oxide having multiple valence states (e.g., SnO2); and a compound which can bind water to its structure (e.g., silica gel). This catalyst is ideally suited for application to high-powered pulsed, CO2 lasers operating in a sealed or closed-cycle condition.

  7. Catalyst for carbon monoxide oxidation

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T. (Inventor); Miller, Irvin M. (Inventor); Brown, David R. (Inventor); Davis, Patricia P. (Inventor); Schryer, David R. (Inventor); Brown, Kenneth G. (Inventor); Vannorman, John D. (Inventor)

    1991-01-01

    A catalyst for the combination of CO and O2 to form CO2 which includes a platinum group metal, e.g., platinum; a reducible metal oxide having mulitple valence states, e.g., SnO2; and a compound which can bind water to its structure, e.g., silica gel. This catalyst is ideally suited for application to high powered, pulsed, CO2 lasers operating in a sealed or closed cycle condition.

  8. Fine Particle Scrubbing: A Proceedings

    ERIC Educational Resources Information Center

    Journal of the Air Pollution Control Association, 1974

    1974-01-01

    These articles deal with the proceedings of a 1974 symposium on the use of wet scrubbers for the control of fine particle air pollutants. Various wet scrubbers, their engineering, performance, efficiency, and future are discussed. Tables, formulas, and models are included. (TK)

  9. Fine structure in krypton excimer

    SciTech Connect

    Hemici, M.; Saoudi, R.; Descroix, E.; Audouard, E.; Laporte, P. ); Spiegelmann, F. )

    1995-04-01

    By using laser reduced fluorescence techniques, molecular absorption from the first relaxed excited excimer states of krypton is obtained in the 960--990-nm wavelength range. Five bands are observed and analyzed by comparison with an [ital ab] [ital initio] calculated spectrum. The fine structure is thus evidenced.

  10. Fine Arts. [SITE 2002 Section].

    ERIC Educational Resources Information Center

    Robin, Bernard, Ed.

    This document contains two papers on fine arts from the SITE (Society for Information Technology & Teacher Education) 2002 conference. "Expanding the Boundaries of the Music Education of the Elementary Teacher Classroom with Information Technology" (Cheryl Jackson) reports on how information technology is used in a music methods…

  11. Regional Background Fine Particulate Matter

    EPA Science Inventory

    A modeling system composed of the global model GEOS-Chem providing hourly lateral boundary conditions to the regional model CMAQ was used to calculate the policy relevant background level of fine particulate: matter. Simulations were performed for the full year of 2004 over the d...

  12. Fine Arts Education. Research Brief

    ERIC Educational Resources Information Center

    Walker, Karen

    2006-01-01

    What are the benefits of a Fine Arts education? With the advent of the No Child Left Behind Act of 2000, extreme pressure has been put on schools to concentrate the majority of their efforts and resources on reading, math and science skills. Yet, NCLB also states that every child should be well-versed in the arts. Some research has shown that when…

  13. Neural Correlates of Divided Attention in Natural Scenes.

    PubMed

    Fagioli, Sabrina; Macaluso, Emiliano

    2016-09-01

    Individuals are able to split attention between separate locations, but divided spatial attention incurs the additional requirement of monitoring multiple streams of information. Here, we investigated divided attention using photos of natural scenes, where the rapid categorization of familiar objects and prior knowledge about the likely positions of objects in the real world might affect the interplay between these spatial and nonspatial factors. Sixteen participants underwent fMRI during an object detection task. They were presented with scenes containing either a person or a car, located on the left or right side of the photo. Participants monitored either one or both object categories, in one or both visual hemifields. First, we investigated the interplay between spatial and nonspatial attention by comparing conditions of divided attention between categories and/or locations. We then assessed the contribution of top-down processes versus stimulus-driven signals by separately testing the effects of divided attention in target and nontarget trials. The results revealed activation of a bilateral frontoparietal network when dividing attention between the two object categories versus attending to a single category but no main effect of dividing attention between spatial locations. Within this network, the left dorsal premotor cortex and the left intraparietal sulcus were found to combine task- and stimulus-related signals. These regions showed maximal activation when participants monitored two categories at spatially separate locations and the scene included a nontarget object. We conclude that the dorsal frontoparietal cortex integrates top-down and bottom-up signals in the presence of distractors during divided attention in real-world scenes.

  14. The innovation catalysts.

    PubMed

    Martin, Roger L

    2011-06-01

    A few years ago the software development company Intuit realized that it needed a new approach to galvanizing customers. The company's Net Promoter Score was faltering, and customer recommendations of new products were especially disappointing. Intuit decided to hold a two-day, off-site meeting for the company's top 300 managers with a focus on the role of design in innovation. One of the days was dedicated to a program called Design for Delight. The centerpiece of the day was a PowerPoint presentation by Intuit founder Scott Cook, who realized midway through that he was no Steve Jobs: The managers listened dutifully, but there was little energy in the room. By contrast, a subsequent exercise in which the participants worked through a design challenge by creating prototypes, getting feedback, iterating, and refining, had them mesmerized. The eventual result was the creation of a team of nine design-thinking coaches--"innovation catalysts"--from across Intuit who were made available to help any work group create prototypes, run experiments, and learn from customers. The process includes a "painstorm" (to determine the customer's greatest pain point), a "soljam" (to generate and then winnow possible solutions), and a "code-jam" (to write code "good enough" to take to customers within two weeks). Design for Delight has enabled employees throughout Intuit to move from satisfying customers to delighting them.

  15. Interfaces in Heterogeneous Catalysts: Advancing Mechanistic Understanding through Atomic-Scale Measurements.

    PubMed

    Gao, Wenpei; Hood, Zachary D; Chi, Miaofang

    2017-04-18

    interfaces and providing deeper insight for fine-tuning and optimizing catalyst properties. Scanning transmission electron microscopy (STEM) has long been a primary characterization technique used for studying nanomaterials because of its exceptional imaging resolution and simultaneous chemical analysis. Over the past decade, advances in STEM, that is, the commercialization of both aberration correctors and monochromators, have significantly improved the spatial and energy resolution. Imaging atomic structures with subangstrom resolution and identifying chemical species with single-atom sensitivity are now routine for STEM. These advancements have greatly benefitted catalytic research. For example, the roles of lattice strain and surface elemental distribution and their effect on catalytic stability and reactivity have been well documented in bimetallic catalysts. In addition, three-dimensional atomic structures revealed by STEM tomography have been integrated in theoretical modeling for predictive catalyst NP design. Recent developments in stable electronic and mechanical devices have opened opportunities to monitor the evolution of catalysts in operando under synthesis and reaction conditions; high-speed direct electron detectors have achieved sub-millisecond time resolutions and allow for rapid structural and chemical changes to be captured. Investigations of catalysts using these latest microscopy techniques have provided new insights into atomic-level catalytic mechanisms. Further integration of new microscopy methods is expected to provide multidimensional descriptions of interfaces under relevant synthesis and reaction conditions. In this Account, we discuss recent insights on understanding catalyst activity, selectivity, and stability using advanced STEM techniques, with an emphasis on how critical interfaces dictate the performance of precious metal-based heterogeneous catalysts. The role of extended interfacial structures, including those between core and shell

  16. THE FINE STRUCTURE OF GIARDIA MURIS

    PubMed Central

    Friend, Daniel S.

    1966-01-01

    Giardia is a noninvasive intestinal zooflagellate. This electron microscope study demonstrates the fine structure of the trophozoite of Giardia muris in the lumen of the duodenum of the mouse as it appears after combined glutaraldehyde and acrolein fixation and osmium tetroxide postfixation. Giardia muris is of teardrop shape, rounded anteriorly, with a convex dorsal surface and a concave ventral one. The anterior two-thirds of the ventral surface is modified to form an adhesive disc. The adhesive disc is divided into 2 lobes whose medial surfaces form the median groove. The marginal grooves are the spaces between the lateral crests of the adhesive disc and a protruding portion of the peripheral cytoplasm. The organism has 2 nuclei, 1 dorsal to each lobe of the adhesive disc. Between the anterior poles of the nuclei, basal bodies give rise to 8 paired flagella. The median body, unique to Giardia, is situated between the posterior poles of the nuclei. The cytoplasm contains 300-A granules that resemble particulate glycogen, 150- to 200-A granules that resemble ribosomes, and fusiform clefts. The dorsal portion of the cell periphery is occupied by a linear array of flattened vacuoles, some of which contain clusters of dense particles. The ventrolateral cytoplasm is composed of regularly packed coarse and fine filaments which extend as a striated flange around the adhesive disc. The adhesive disc is composed of a layer of microtubules which are joined to the cytoplasm by regularly spaced fibrous ribbons. The plasma membrane covers the ventral and lateral surfaces of the disc. The median body consists of an oval aggregate of curved microtubules. Microtubules extend ventrally from the median body to lie alongside the caudal flagella. The intracytoplasmic portions of the caudal, lateral, and anterior flagella course considerable distances, accompanied by hollow filaments adjacent to their outer doublets. The intracytoplasmic portions of the anterior flagella are

  17. Nano-Engineered Catalysts for Direct Methanol Fuel Cells

    NASA Technical Reports Server (NTRS)

    Myung, Nosang; Narayanan, Sekharipuram; Wiberg, Dean

    2008-01-01

    Nano-engineered catalysts, and a method of fabricating them, have been developed in a continuing effort to improve the performances of direct methanol fuel cells as candidate power sources to supplant primary and secondary batteries in a variety of portable electronic products. In order to realize the potential for high energy densities (as much as 1.5 W h/g) of direct methanol fuel cells, it will be necessary to optimize the chemical compositions and geometric configurations of catalyst layers and electrode structures. High performance can be achieved when catalyst particles and electrode structures have the necessary small feature sizes (typically of the order of nanometers), large surface areas, optimal metal compositions, high porosity, and hydrophobicity. The present method involves electrodeposition of one or more catalytic metal(s) or a catalytic-metal/polytetrafluoroethylene nanocomposite on an alumina nanotemplate. The alumina nanotemplate is then dissolved, leaving the desired metal or metal/polytetrafluoroethylene-composite catalyst layer. Unlike some prior methods of making fine metal catalysts, this method does not involve processing at elevated temperature; all processing can be done at room temperature. In addition, this method involves fewer steps and is more amenable to scaling up for mass production. Alumina nanotemplates are porous alumina membranes that have been fabricated, variously, by anodizing either pure aluminum or aluminum that has been deposited on silicon by electronbeam evaporation. The diameters of the pores (7 to 300 nm), areal densities of pores (as much as 7 x 10(exp 10)sq cm), and lengths of pores (up to about 100 nm) can be tailored by selection of fabrication conditions. In a given case, the catalytic metal, catalytic metal alloy, or catalytic metal/ polytetrafluoroethylene composite is electrodeposited in the pores of the alumina nanotemplate. The dimensions of the pores, together with the electrodeposition conditions

  18. Characterization of Na+- beta-Zeolite Supported Pd and Pd Ag Bimetallic Catalysts using EXAFS, TEM and Flow Reactor

    SciTech Connect

    Huang,W.; Lobo, R.; Chen, J.

    2008-01-01

    Flow reactor studies of the selective hydrogenation of acetylene in the presence of ethylene have been performed on Na+ exchanged {beta}-zeolite supported Pd, Ag and PdAg catalysts, as an extension of our previous batch reactor studies [W. Huang, J.R. McCormick, R.F. Lobo, J.G. Chen, J. Catal. 246 (2007) 40-51]. Results from flow reactor studies show that the PdAg/Na+-{beta}-zeolite bimetallic catalyst has lower activity than Pd/Na+-{beta}-zeolite monometallic catalyst, while Ag/Na+-{beta}-zeolite does not show any activity for acetylene hydrogenation. However, the selectivity for the PdAg bimetallic catalyst is much higher than that for either the Pd catalyst or Ag catalyst. The selectivity to byproduct (ethane) is greatly inhibited on the PdAg bimetallic catalyst as well. The results from the current flow reactor studies confirmed the pervious results from batch reactor studies [W. Huang, J.R. McCormick, R.F. Lobo, J.G. Chen, J. Catal. 246 (2007) 40-51]. In addition, we used transmission electron microscope (TEM), extended X-ray absorption fine structure (EXAFS), and FTIR of CO adsorption to confirm the formation of Pd-Ag bimetallic alloy in the PdAg/Na+-{beta}-zeolite catalyst.

  19. Template Effect and Ligand Substitution Methods for the Synthesis of Iron Catalysts: A Two-Part Experiment for Inorganic Chemistry

    ERIC Educational Resources Information Center

    Sues, Peter E.; Cai, Kuihua; McIntosh, Douglas F.; Morris, Robert H.

    2015-01-01

    Asymmetric transfer hydrogenation is an important transformation for the production of fine chemicals. Traditionally, platinum group metals are used to catalyze this reaction, but recent pressure for greener practices has driven the development of base-metal catalysts. Due to the growing interest in this area of research, the underlying concepts…

  20. Template Effect and Ligand Substitution Methods for the Synthesis of Iron Catalysts: A Two-Part Experiment for Inorganic Chemistry

    ERIC Educational Resources Information Center

    Sues, Peter E.; Cai, Kuihua; McIntosh, Douglas F.; Morris, Robert H.

    2015-01-01

    Asymmetric transfer hydrogenation is an important transformation for the production of fine chemicals. Traditionally, platinum group metals are used to catalyze this reaction, but recent pressure for greener practices has driven the development of base-metal catalysts. Due to the growing interest in this area of research, the underlying concepts…

  1. Nanostructured catalysts for organic transformations.

    PubMed

    Chng, Leng Leng; Erathodiyil, Nandanan; Ying, Jackie Y

    2013-08-20

    The development of green, sustainable and economical chemical processes is one of the major challenges in chemistry. Besides the traditional need for efficient and selective catalytic reactions that will transform raw materials into valuable chemicals, pharmaceuticals and fuels, green chemistry also strives for waste reduction, atomic efficiency and high rates of catalyst recovery. Nanostructured materials are attractive candidates as heterogeneous catalysts for various organic transformations, especially because they meet the goals of green chemistry. Researchers have made significant advances in the synthesis of well-defined nanostructured materials in recent years. Among these are novel approaches that have permitted the rational design and synthesis of highly active and selective nanostructured catalysts by controlling the structure and composition of the active nanoparticles (NPs) and by manipulating the interaction between the catalytically active NP species and their support. The ease of isolation and separation of the heterogeneous catalysts from the desired organic product and the recovery and reuse of these NPs further enhance their attractiveness as green and sustainable catalysts. This Account reviews recent advances in the use of nanostructured materials for catalytic organic transformations. We present a broad overview of nanostructured catalysts used in different types of organic transformations including chemoselective oxidations and reductions, asymmetric hydrogenations, coupling reactions, C-H activations, oxidative aminations, domino and tandem reactions, and more. We focus on recent research efforts towards the development of the following nanostructured materials: (i) nanostructured catalysts with controlled morphologies, (ii) magnetic nanocomposites, (iii) semiconductor-metal nanocomposites, and (iv) hybrid nanostructured catalysts. Selected examples showcase principles of nanoparticle design such as the enhancement of reactivity, selectivity

  2. Fine and coarse components in surface sediments from Bikini Lagoon

    SciTech Connect

    Noshkin, V. E., LLNL

    1997-01-01

    In 1979, 21 years after the moratorium on nuclear testing in the Marshall Islands, surface sediment samples (to depths of 2 and 4 cm) were collected from 87 locations in the lagoon of Bikini Atoll, one of the two sites in the Marshall Islands used by the United States to test nuclear devices from 1946 through 1958. The main purpose for the collections was to map the distribution of long-lived man-made radionuclides associated with the bottom material. In addition the samples were processed to estimate the fraction of fine and coarse components to show, by comparison, what modifications occurred in the composition since the sediments were first described in samples collected before testing in 1946. Nuclear testing produced more finely divided material that is now found in the surface sediment layer over large areas of the lagoon and especially in regions of the lagoon and reef adjacent to test sites. The 5 cratering events alone at Bikini Atoll redistributed sufficient material to account for the higher inventory of fine material found over the surface 4 cm of the sediment of the lagoon. Although the fraction of fine material in the bottom sediments was altered by the nuclear events, the combined processes of formation, transport and deposition were not sufficiently dynamic to greatly change the general geographical features of the major sedimentary components over most of the lagoon floor.

  3. [Promoting nursing competitiveness: introduction to the digital divide].

    PubMed

    Lin, Chun-Hsu; Lee, Ting-Ting

    2010-02-01

    Increasingly sophisticated information technology (IT) has widened the gap (the so-called "digital divide") between those with effective access to IT resources and those without. Problems related to the digital divide exist in every country. In addition to level of familiarity with technology, the divide can also be influenced by factors of race, gender, age, education, economic status and area of residence. The digital divide may be ameliorated through technology innovations in terms of access to information, information application and information literacy. As IT is an increasingly significant component of modern healthcare, it may be expected that the "width" of the potential gap widens as IT applications increase in sophistication. Nursing professionals must keep abreast of advancing technologies in order to narrow the digital divide. To cope with this challenge, nursing professionals should enhance their understanding of new technologies beyond what is taught in formal education curricula. This knowledge enhancement may be attained through self learning or on-the-job training in nursing informatics. Content could cover hospital information system (IS) usage, security, applications and web access. This will improve the ability of nursing staff to face the current IT challenge.

  4. Attrition Resistant Iron-Based Catalysts For F-T SBCRs

    SciTech Connect

    Adeyinka A. Adeyiga

    2006-01-31

    {alpha} of 0.9. Research is proposed to enable further development and optimization of these catalysts by (1) better understanding the role and interrelationship of various catalyst composition and preparation parameters on attrition resistance, activity, and selectivity of these catalysts, (2) the presence of sulfide ions on a precipitated iron catalyst, and (3) the effect of water on sulfided iron F-T catalysts for its activity, selectivity, and attrition. Catalyst preparations will be based on spray drying. The research employed, among other measurements, attrition testing and F-T synthesis at high pressure. Catalyst activity and selectivity is evaluated using a small fixed-bed reactor and a continuous stirred tank reactor (CSTR). The catalysts were prepared by co-precipitation, followed by binder addition and spray drying at 250 C in a 1-m-diameter, 2-m-tall spray dryer. The binder silica content was varied from 0 to 20 wt%. The results show that the use of small amounts of precipitated SiO{sub 2} alone in spray-dried Fe catalysts can result in good attrition resistance. All catalysts investigated with SiO2 wt% {le} 12 produced fines less than 10 wt% during the jet cup attrition test, making them suitable for long-term use in a slurry bubble column reactor. Thus, concentration rather than the type of SiO{sub 2} incorporated into catalyst has a more critical impact on catalyst attrition resistance of spray-dried Fe catalysts. Lower amounts of SiO{sub 2} added to a catalyst give higher particle densities and therefore higher attrition resistances. In order to produce a suitable SBCR catalyst, however, the amount of SiO{sub 2} added has to be optimized to provide adequate surface area, particle density, and attrition resistance. Two of the catalysts with precipitated and binder silica were tested in Texas A&M University's CSTR (Autoclave Engineers). The two catalysts were also tested at The Center for Applied Energy Research in Lexington, Kentucky of the University of

  5. Biomimetic Single-Site Heterogeneous Catalysts: Design Strategies and Catalytic Potential

    NASA Astrophysics Data System (ADS)

    Xuereb, David; Dzierzak, Joanna; Raja, Robert

    Enzymes catalyze the most fundamental reactions in organic chemistry from simple oxidations of straight chain alkanes to complex C-C bond forming reactions with exceptional selectivity. Mimicking the active site of an enzyme by immobilising a well defined amino acid containing transition-metal centre on a robust inorganic framework, provides a powerful catalyst that can be utilized in the production of fine chemicals and complicated drug molecules. Porous aluminosilicates and mesoporous silicas offer suitable supports for single-site bio-derived catalysts. These materials can be created from a range of methodologies and the different strategies used for immobilisation can greatly affect the nature of the active catalyst. The routes by which these catalysts are immobilised have also given the potential to derivatize inorganic structures with amino acids, not just for complexation to metal centres but for use as organocatalysts as well. These metal free bio-derivatized frameworks offer advantages over their homogeneous counterparts and can carry out stereoselective reactions with great effectiveness. Herein, the routes to heterogenizing biomimetic catalysts will be critically assessed and depending on the methods used, suitable active catalysts for use in chemo- and stereoselective transformations can be developed.

  6. Laser-activated membrane introduction mass spectrometry for high-throughput evaluation of bulk heterogeneous catalysts.

    PubMed

    Nayar, Amit; Liu, Renxuan; Allen, Robert J; McCall, Michael J; Willis, Richard R; Smotkin, Eugene S

    2002-05-01

    Laser-activated membrane introduction mass spectrometry (LAMIMS), a high-throughput screening method, evaluates heterogeneous catalysts under realistic reactor conditions. It is a precise, versatile system requiring no moving parts. The catalyst array is supported on carbon paper overlaid upon a silicone rubber membrane configured in a variation of membrane introduction mass spectrometry as introduced by Cooks. The carbon paper serves as a heat-dissipating gas diffusion layer that permits laser heating of catalyst samples far above the decomposition temperature of the polymer membrane that separates the array from the mass spectrometer vacuum chamber. A computer-controlled CO2 bar code writing laser is used for fine-tune heating of the catalyst spots above the base temperature of the LAMIMS reactor. The detailed design and performance of LAMIMS is demonstrated on arrays of "real world" bulk water-gas shift catalysts using natural and isotopically labeled reactor feed streams. A bulk catalyst array spot can be evaluated for activity and selectivity in as little as 1.5 min. All array screening results were confirmed by industrial microreactor evaluations.

  7. Catalytic wet-air oxidation of a chemical plant wastewater over platinum-based catalysts.

    PubMed

    Cybulski, Andrzej; Trawczyński, Janusz

    2006-01-01

    Catalytic wet-air oxidation (CWAO) of wastewater (chemical oxygen demand [COD] = 1800 mg O2/dm3) from a fine chemicals plant was investigated in a fixed-bed reactor at T = 393-473 K under total pressure of 5.0 or 8.0 MPa. Catalysts containing 0.3% wt. of platinum deposited on two supports, mixed silica-titania (SM1) and carbon black composites (CBC) were used. The CBC-supported catalyst appeared to be more active than the SM1-supported one. A slow decrease of activity of the platinum on SM1 (Pt-SM1) during the long-term operation is attributed to recrystallization of titania and leaching of a support component, while the Pt-CBC catalyst is deteriorated, owing to combustion of the support component. The power-law-kinetic equations were used to describe the rate of COD removal at CWAO over the catalysts. The kinetic parameters of COD reduction for the wastewater were determined and compared with the kinetic parameters describing phenol oxidation over the same catalysts. Rates of COD removal for the wastewater were found higher than those for phenol oxidation over the same catalysts and under identical operating conditions.

  8. Production of biodiesel fuel from canola oil with dimethyl carbonate using an active sodium methoxide catalyst prepared by crystallization.

    PubMed

    Kai, Takami; Mak, Goon Lum; Wada, Shohei; Nakazato, Tsutomu; Takanashi, Hirokazu; Uemura, Yoshimitsu

    2014-07-01

    In this study, a novel method for the production of biodiesel under mild conditions using fine particles of sodium methoxide formed in dimethyl carbonate (DMC) is proposed. Biodiesel is generally produced from vegetable oils by the transesterification of triglycerides with methanol. However, this reaction produces glycerol as a byproduct, and raw materials are not effectively utilized. Transesterification with DMC has recently been studied because glycerol is not formed in the process. Although solid-state sodium methoxide has been reported to be inactive for this reaction, the catalytic activity dramatically increased with the preparation of fine catalyst powders by crystallization. The transesterification of canola oil with DMC was studied using this catalyst for the preparation of biodiesel. A conversion greater than 96% was obtained at 65°C for 2h with a 3:1M ratio of DMC and oil and 2.0 wt% catalyst. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Preferential processing of tactile events under conditions of divided attention.

    PubMed

    Hanson, James V M; Whitaker, David; Heron, James

    2009-10-07

    Differences in transduction and transmission latencies of visual, auditory and tactile events cause corresponding differences in simple reaction time. As reaction time is usually measured in unimodal blocks, it is unclear whether such latency differences also apply when observers monitor multiple sensory channels. We investigate this by comparing reaction time when attention is focused on a single modality, and when attention is divided between multiple modalities. Results show that tactile reaction time is unaffected by dividing attention, whereas visual and auditory reaction times are significantly and asymmetrically increased. These findings show that tactile information is processed preferentially by the nervous system under conditions of divided attention, and suggest that tactile events may be processed preattentively.

  10. Selectively Distracted: Divided Attention and Memory for Important Information.

    PubMed

    Middlebrooks, Catherine D; Kerr, Tyson; Castel, Alan D

    2017-08-01

    Distractions and multitasking are generally detrimental to learning and memory. Nevertheless, people often study while listening to music, sitting in noisy coffee shops, or intermittently checking their e-mail. The current experiments examined how distractions and divided attention influence one's ability to selectively remember valuable information. Participants studied lists of words that ranged in value from 1 to 10 points while completing a digit-detection task, while listening to music, or without distractions. Though participants recalled fewer words following digit detection than in the other conditions, there were no significant differences between conditions in terms of selectively remembering the most valuable words. Similar results were obtained across a variety of divided-attention tasks that stressed attention and working memory to different degrees, which suggests that people may compensate for divided-attention costs by selectively attending to the most valuable items and that factors that worsen memory do not necessarily impair the ability to selectively remember important information.

  11. Dividing Cells Regulate Their Lipid Composition and Localization

    PubMed Central

    Atilla-Gokcumen, G. Ekin; Muro, Eleonora; Relat-Goberna, Josep; Sasse, Sofia; Bedigian, Anne; Coughlin, Margaret L.; Garcia-Manyes, Sergi; Eggert, Ulrike S.

    2014-01-01

    Summary Although massive membrane rearrangements occur during cell division, little is known about specific roles that lipids might play in this process. We report that the lipidome changes with the cell cycle. LC-MS-based lipid profiling shows that 11 lipids with specific chemical structures accumulate in dividing cells. Using AFM, we demonstrate differences in the mechanical properties of live dividing cells and their isolated lipids relative to nondividing cells. In parallel, systematic RNAi knockdown of lipid biosynthetic enzymes identified enzymes required for division, which highly correlated with lipids accumulated in dividing cells. We show that cells specifically regulate the localization of lipids to midbodies, membrane-based structures where cleavage occurs. We conclude that cells actively regulate and modulate their lipid composition and localization during division, with both signaling and structural roles likely. This work has broader implications for the active and sustained participation of lipids in basic biology. PMID:24462247

  12. Ouroboros: A Tool for Building Generic, Hybrid, Divide& Conquer Algorithms

    SciTech Connect

    Johnson, J R; Foster, I

    2003-05-01

    A hybrid divide and conquer algorithm is one that switches from a divide and conquer to an iterative strategy at a specified problem size. Such algorithms can provide significant performance improvements relative to alternatives that use a single strategy. However, the identification of the optimal problem size at which to switch for a particular algorithm and platform can be challenging. We describe an automated approach to this problem that first conducts experiments to explore the performance space on a particular platform and then uses the resulting performance data to construct an optimal hybrid algorithm on that platform. We implement this technique in a tool, ''Ouroboros'', that automatically constructs a high-performance hybrid algorithm from a set of registered algorithms. We present results obtained with this tool for several classical divide and conquer algorithms, including matrix multiply and sorting, and report speedups of up to six times achieved over non-hybrid algorithms.

  13. Bridging the Digital Divide for urban seniors: community partnership.

    PubMed

    Cresci, M Kay; Jarosz, Patricia A

    2010-01-01

    Computers and the Internet offer older adults resources for improving health. For many older adults, the "Digital Divide" (the social, economic, and demographic factors that exist between individuals who use computers and those who do not) is a barrier to taking advantage of these resources. Bridging the Digital Divide by making computers and the Internet more accessible and making online health information more usable for older adults has the potential to improve health of older adults. This article describes a strategy for closing the Digital Divide for urban seniors through the formation of a community- university partnership with the goal of improving health and well-being through the use of online health information.

  14. Pretreatment of CO oxidation catalysts

    NASA Technical Reports Server (NTRS)

    Vannorman, John D.

    1988-01-01

    CO oxidation catalysts with high activity in the range of 25 C to 100 C are important for long-life, closed-cycle operation of pulsed carbon dioxide 2 lasers. A reductive pretreatment with either CO or H sub 2 was shown to significantly enhance the activity of a commerically-available platinum on tin (IV) oxide (Pt/SnO2) catalyst relative to an oxidative or inert pretreatment or no pretreatment. Pretreatment at temperatures of 175 C and above caused an initial dip in observed CO or O sub 2 loss or CO sub 2 formation in a test gas mixture of 1 percent CO and 0.5 percent O sub 2 in a He gas matrix before a steady-state yield was obtained. This dip was found to be caused by dehydration of the surface of the catalyst and was readily eliminated by humidifying the catalyst or the test gas mixture. It was also found that too much moisture resulted in a lower overall yield of CO sub 2. Under similar conditions, it is hypothesized that the effect of the humidification is to increase the concentration of OH groups on the surface of the catalyst. The effect of having high concentration of CO sub 2 in the test gas mixture upon the loss of CO and O sub 2 as well as the effect of periods of relaxation of the catalyst under non-test gas conditions was studied. The purpose of these studies was to gain an insight into the mechanism of CO oxidation on this type of catalyst.

  15. Catalyst for coal liquefaction process

    DOEpatents

    Huibers, Derk T. A.; Kang, Chia-Chen C.

    1984-01-01

    An improved catalyst for a coal liquefaction process; e.g., the H-Coal Process, for converting coal into liquid fuels, and where the conversion is carried out in an ebullated-catalyst-bed reactor wherein the coal contacts catalyst particles and is converted, in addition to liquid fuels, to gas and residual oil which includes preasphaltenes and asphaltenes. The improvement comprises a catalyst selected from the group consisting of the oxides of nickel molybdenum, cobalt molybdenum, cobalt tungsten, and nickel tungsten on a carrier of alumina, silica, or a combination of alumina and silica. The catalyst has a total pore volume of about 0.500 to about 0.900 cc/g and the pore volume comprises micropores, intermediate pores and macropores, the surface of the intermediate pores being sufficiently large to convert the preasphaltenes to asphaltenes and lighter molecules. The conversion of the asphaltenes takes place on the surface of micropores. The macropores are for metal deposition and to prevent catalyst agglomeration. The micropores have diameters between about 50 and about 200 angstroms (.ANG.) and comprise from about 50 to about 80% of the pore volume, whereas the intermediate pores have diameters between about 200 and 2000 angstroms (.ANG.) and comprise from about 10 to about 25% of the pore volume, and the macropores have diameters between about 2000 and about 10,000 angstroms (.ANG.) and comprise from about 10 to about 25% of the pore volume. The catalysts are further improved where they contain promoters. Such promoters include the oxides of vanadium, tungsten, copper, iron and barium, tin chloride, tin fluoride and rare earth metals.

  16. Characterization and functionalities of Pd/hydrotalcite catalysts

    NASA Astrophysics Data System (ADS)

    Naresh, Dhachapally; Kumar, Vanama Pavan; Harisekhar, Mitta; Nagaraju, Nekkala; Putrakumar, Balla; Chary, Komandur V. R.

    2014-09-01

    A series of palladium supported on calcined hydrotalcite (CHT) catalysts with varying palladium (Pd) loadings (1.0-8.0 wt%) were prepared by impregnation method. Their catalytic performance was evaluated for the reductive amination of phenol to aniline that showed a tremendous interest in the chemical industry. The catalysts were characterized by BET surface area, XRD, TEM, XPS, TPR of H2, TPD of CO2 and CO chemisorption. BET surface area decreased continuously with increase in Pd content. XRD results confirmed the changes in the crystalline phases with altering Pd content. TEM results showed the formation of fine particles at lower loadings and agglomerates at higher loadings. TPR profiles revealed that the reducibility increases with increase of Pd loading. CO2 TPD results illustrate the catalysts basicity increases with increase of Pd loading up to 4.0 wt% and decreases at higher loadings. Pd dispersion, metal area and crystallite sizes were determined by CO chemisorption method. Pd dispersion and metal area decreases with increase of Pd content and crystallite sizes. The results demonstrated that the Pd dispersion and basic properties are depending on the Pd loading. The catalytic performance clearly showed that the increase Pd loading the conversion of phenol increased up to 2.0 wt% and level off beyond the loading. The catalytic properties are well correlated with the active Pd sites determined by CO chemisorption, dispersion and basicity.

  17. Dopants adsorbed as single atoms prevent degradation of catalysts

    NASA Astrophysics Data System (ADS)

    Wang, Sanwu; Borisevich, Albina Y.; Rashkeev, Sergey N.; Glazoff, Michael V.; Sohlberg, Karl; Pennycook, Stephen J.; Pantelides, Sokrates T.

    2004-03-01

    The design of catalysts with desired chemical and thermal properties is viewed as a grand challenge for scientists and engineers. For operation at high temperatures, stability against structural transformations is a key requirement. Although doping has been found to impede degradation, the lack of atomistic understanding of the pertinent mechanism has hindered optimization. For example, porous γ-Al2O3, a widely used catalyst and catalytic support, transforms to non-porous α-Al2O3 at ~1,100 °C (refs 7-10). Doping with La raises the transformation temperature to ~1,250 °C, but it has not been possible to establish if La atoms enter the bulk, adsorb on surfaces as single atoms or clusters, or form surface compounds. Here, we use direct imaging by aberration-corrected Z-contrast scanning transmission electron microscopy coupled with extended X-ray absorption fine structure and first-principles calculations to demonstrate that, contrary to expectations, stabilization is achieved by isolated La atoms adsorbed on the surface. Strong binding and mutual repulsion of La atoms effectively pin the surface and inhibit both sintering and the transformation to α-Al2O3. The results provide the first guidelines for the choice of dopants to prevent thermal degradation of catalysts and other porous materials.

  18. Chemical composition of emissions from urban sources of fine organic aerosol

    SciTech Connect

    Hildemann, L.M.; Markowski, G.R.; Cass, G.R. )

    1991-04-01

    A dilution source sampling system was used to collect primary fine aerosol emissions from important sources of urban organic aerosol, including a boiler burning No. 2 fuel oil, a home fireplace, a fleet of catalyst-equipped and noncatalyst automobiles, heavy-duty diesel trucks, natural gas home appliances, and meat cooking operations. Alternative dilution sampling techniques were used to collect emissions from cigarette smoking and a roofing tar pot, and grab sample techniques were employed to characterize paved road dust, brake lining wear, and vegetative detritus. Organic aerosol constituted the majority of the fine aerosol mass emitted from many of the sources tested. Fine primary organic aerosol emissions within the heavily urbanized western portion of the Los Angeles Basin were determined to total 29.8 metric ton/day. Over 40% of these organic aerosol emissions are from anthropogenic pollution sources that are expected to emit contemporary (nonfossil) aerosol carbon, in good agreement with the available ambient monitoring data.

  19. On the neural basis of focused and divided attention.

    PubMed

    Nebel, Katharina; Wiese, Holger; Stude, Philipp; de Greiff, Armin; Diener, Hans-Christoph; Keidel, Matthias

    2005-12-01

    Concepts of higher attention functions distinguish focused and divided attention. The present study investigated whether these mental abilities are mediated by common or distinct neural substrates. In a first experiment, 19 healthy subjects were examined with functional brain imaging (fMRI) while they attended to either one or both of two simultaneously presented visual information streams and responded to repetitive stimuli. This experiment resembled a typical examination of these mental functions with the single task demanding focused and the dual task conditions requiring divided attention. Both conditions activated a widespread, mainly right-sided network including dorso- and ventrolateral prefrontal structures, superior and inferior parietal cortex, and anterior cingulate gyrus. Under higher cognitive demands of divided attention, activity in these structures was enhanced and left-sided homologues were recruited. In a second experiment investigating another 17 subjects with almost the same paradigm, it was accounted for that in most dual task investigations of focused and divided attention the single tasks are easier to process than their combined presentation. Therefore, the task difficulty of focused attention tasks was increased. Almost the same activity pattern observed during division of attention was now found during focusing attention. Comparing both attentional states matched for task difficulty, differences were found in visual but not in prefrontal or parietal cortex areas. Our results suggest that focused and divided attention depend on largely overlapping neuronal substrates. Differences in activation patterns, especially in prefrontal and parietal areas, may result from unequal demands on executive control due to disparate processing requirements in typical tasks of focused and divided attention: Easier conditions begin with mainly right-sided activity within the attention network. As conditions become more difficult, left-lateralized homologue

  20. Compact waveguide power divider with multiple isolated outputs

    DOEpatents

    Moeller, Charles P.

    1987-01-01

    A waveguide power divider (10) for splitting electromagnetic microwave power and directionally coupling the divided power includes an input waveguide (21) and reduced height output waveguides (23) interconnected by axial slots (22) and matched loads (25) and (26) positioned at the unused ends of input and output guides (21) and (23) respectively. The axial slots are of a length such that the wave in the input waveguide (21) is directionally coupled to the output waveguides (23). The widths of input guide (21) and output guides (23) are equal and the width of axial slots (22) is one half of the width of the input guide (21).

  1. Zeolite catalyst and process for using the catalyst (C-1591)

    SciTech Connect

    Tauster, S.J.; Montagna, A.O.; Steger, J.J.; Fung, S.C.; Cross, V.R.

    1987-01-06

    A process is described for reforming naphtha which comprises (a) contacting the feedstock in the presence of hydrogen at elevated temperatures with a catalyst. The catalyst comprises a type L zeolite containing exchangeable cations of which at least 75 percent are selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, calcium and barium cations and containing at least one Group VIII noble metal from the Periodic Table of Elements. It is characterized in that the particles of the noble metal prior to reduction thereof are well dispersed over the surface of the catalyst and at least about 90% of the noble metal prior to reduction thereof is dispersed in the form of particles having a diameter of less than about 7 A, and (b) recovering the reformed product.

  2. Fine Shades of a Sombrero

    NASA Astrophysics Data System (ADS)

    2000-02-01

    In addition to their scientific value, many of the exposures now being obtained by visiting astronomers to ESO's Very Large Telescope (VLT) are also very beautiful. This is certainly true for this new image of the famous early-type spiral galaxy Messier 104 , widely known as the "Sombrero" (the Mexican hat) because of its particular shape. The colour image was made by a combination of three CCD images from the FORS1 multi-mode instrument on VLT ANTU , recently obtained by Peter Barthel from the Kapteyn Institute (Groningen, The Netherlands) during an observing run at the Paranal Observatory. He and Mark Neeser , also from the Kapteyn Institute, produced the composite images. The galaxy fits perfectly into the 6.8 x 6.8 arcmin 2 field-of-view of the FORS1 camera. A great amount of fine detail is revealed, from the structures in the pronounced dust band in the equatorial plane, to many faint background galaxies that shine through the outer regions. The "Sombrero" is located in the constellation Virgo (The Virgin), at a distance of about 50 million light-years. The overall "sharpness" of this colour image corresponds to about 0.7 arcsec which translates into a resolution of about 170 light-years at that distance. About Messier 104 Messier 104 is the 104th object in the famous catalogue of nebulae by French astronomer Charles Messier (1730 - 1817). It was not included in the first two editions (with 45 objects in 1774; 103 in 1781), but Messier soon thereafter added it by hand in his personal copy as a "very faint nebula". The recession velocity, about 1000 km/sec, was first measured by American astronomer Vesto M. Slipher at the Lowell Observatory in 1912; he was also the first to detect the galaxy's rotation. ESO Press Photo 07c/00 ESO Press Photo 07c/00 [Preview; JPEG: 400 x 307; 59k] [Normal; JPEG: 800 x 614; 308k] [Full-Res; JPEG: 2028 x 1556; 2.3Mb] PR Photo 07c/00 has been processed to show the numerous dust bands in the central plane of the Sombrero galaxy (see

  3. Coking characteristics of reforming catalysts

    SciTech Connect

    Mieville, R.L.

    1986-08-01

    Coking rates were measured for two different ..gamma..-aluminas, each with and without platinum, under near commercial conditions using a gravimetric reactor. Coke on catalyst was characterized by a Temperature-Programmed Oxidation (TPO) technique. With a naphtha feed, coke formed on both aluminas at rates related to the respective population of ..cap alpha..-sites as measured by IR. For the corresponding Pt on alumina catalysts, coke, as measured by TPO, predominantly formed on sites associated with alumina (alumina coke), while coke associated with Pt (Pt coke), was relatively minor. With a n-heptane feed, under the same conditions, coke formation on both aluminas was much less than with the naphtha feed. However, the corresponding Pt on alumina catalysts generated comparatively more coke with a higher proportion associated with Pt. A correspondence between this proportion of Pt coke and the decline in reforming activity was observed. It is postulated that most of the coke produced during naphtha reforming with an active catalyst is formed by a reaction between ..cap alpha..-sites on alumina and certain components in the feed via a polymerization mechanism. This type of coke has minimal effect on the reforming reactivity of the catalyst. However, in n-heptane reforming, about 50% of the coke also results from precursors formed from reactions with Pt. In either case, coke associated with Pt appears to be the probable cause of deactivation. 22 references.

  4. Combinatorial methods in catalyst development

    NASA Astrophysics Data System (ADS)

    Lauterbach, Jochen

    2002-03-01

    The discovery of novel catalytic materials has traditionally followed a hypothesize-and-test methodology with limited systematic guidance. In the past few years, a high-throughput approach to catalysis has emerged, which includes efficient sample preparation, parallel processing, and rapid sequential or parallel testing of large diversities of different catalytic materials. A short review of high-throughput screening techniques will be presented. We combine computer-aided materials design techniques with high-throughput screening methodologies for automating and systematizing the catalyst design process. Rapid-scan Fourier transform infrared hyperspectral imaging is used as the main tool for the parallel investigation of multiple member supported catalyst systems. It combines the chemical specificity of infrared spectroscopy with the ability to rapidly analyze multiple samples simultaneously. Using CO oxidation, propylene oxidation, and NO decomposition as model systems, it will be demonstrated that FTIR imaging is well suited to high throughput parallel analysis of reaction products from supported catalyst libraries. A novel, systems-oriented, integrated knowledge architecture that enables the use of high-throughput data for catalyst design will be presented. This new approach involves solving the forward problem of performance prediction using hybrid first principles, rule-based and statistical models and then using that solution to solve the inverse problem: the determination of the optimal catalyst descriptors that meet the target performance.

  5. State of the art of Lewis acid-containing zeolites: lessons from fine chemistry to new biomass transformation processes.

    PubMed

    Moliner, Manuel

    2014-03-21

    The former synthesis of TS-1 opened new catalytic opportunities for zeolites, especially for their application as selective redox catalysts in several fine chemistry processes. Interestingly, isolated Ti species in the framework positions of hydrophobic zeolites, such as high silica zeolites, offer unique Lewis acid sites even in the presence of protic polar solvents (such as water). Following this discovery, other transition metals (such as Sn, Zr, V, Nb, among others) have been introduced in the framework positions of different hydrophobic zeolitic structures, allowing their application in new fine chemistry processes as very active and selective redox catalysts. Recently, these hydrophobic metallozeolites have been successfully applied as efficient catalysts for several biomass-transformation processes in bulk water. The acquired knowledge from the former catalytic descriptions in fine chemistry processes using hydrophobic Lewis acid-containing zeolites has been essential for their application in these novel biomass transformations. In the present review, I will describe the recent advances in the synthesis of new transition metal-containing zeolites presenting Lewis acid character, and their unique catalytic applications in both fine chemistry and novel biomass-transformations.

  6. Process for cleaning fine coal

    SciTech Connect

    Ennis, R.E.

    1981-08-04

    A process for the wet concentration and cleaning of fine coal is provided which comprises the steps of desliming and thickening a dilute slurry of fine coal and contaminant particles having a size of less than about 10 mm by introducing the same to a hydrocyclone separator to retain a slurry of particles having a size greater than about 0.1 mm, wet concentrating the last-named slurry and removing the heavier contaminant particles by introducing it to an autogenous dense medium separation vessel having a manifold for injecting water at an intermediate level and controlling the underflow of heavier than coal particles to maintain a fluidized bed of heavier particles and causing a slurry of the lighter coal particles to overflow, and concentrating and dewatering the overflow by means of a static or vibratory sizing screen.

  7. Wetter for fine dry powder

    DOEpatents

    Hall, James E.; Williams, Everett H.

    1977-01-01

    A system for wetting fine dry powders such as bentonite clay with water or other liquids is described. The system includes a wetting tank for receiving water and a continuous flow of fine powder feed. The wetting tank has a generally square horizontal cross section with a bottom end closure in the shape of an inverted pyramid. Positioned centrally within the wetting tank is a flow control cylinder which is supported from the walls of the wetting tank by means of radially extending inclined baffles. A variable speed motor drives a first larger propeller positioned immediately below the flow control cylinder in a direction which forces liquid filling the tank to flow downward through the flow control cylinder and a second smaller propeller positioned below the larger propeller having a reverse pitch to oppose the flow of liquid being driven downward by the larger propeller.

  8. Compressive behavior of fine sand.

    SciTech Connect

    Martin, Bradley E.; Kabir, Md. E.; Song, Bo; Chen, Wayne

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  9. Bound zeolite catalyst and process for using the catalyst

    SciTech Connect

    Kao, J.L.; Poeppelmeier, K.R.; Funk, W.G.; Steger, J.J.; Fung, S.C.; Cross, V.R.

    1987-03-10

    A process is described for reforming naphtha. The process comprises (a) contacting the naphtha in the presence of hydrogen at elevated temperatures with a catalyst comprising a binder, a type L zeolite containing exchangeable cations of which at least 75% are selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, calcium and barium, at least one Group VIII noble metal, the particles of which are well dispersed over the surface of the catalyst and at least 90% of the noble metal associated with the zeolite is in the form of particles having a diameter of less than about 7 A; and (b) recovering reformed product.

  10. SOUTHERN FINE PARTICULATE MONITORING PROJECT

    SciTech Connect

    Ashley D. Williamson

    2001-07-01

    This is the third quarterly progress report of the ''Southern Fine Particulate Monitoring Project'', funded by the U.S. Department of Energy's National Energy Technology Laboratory under DOE Cooperative Agreement No. DE-FC26-00NT40770 to Southern Research Institute (SRI). In this two year project SRI will conduct detailed studies of ambient fine particulate matter in the Birmingham, AL metropolitan area. Project objectives include: Augment existing measurements of primary and secondary aerosols at an established urban southeastern monitoring site; Make a detailed database of near-continuous measurements of the time variation of fine particulate mass, composition, and key properties (including particle size distribution); Apply the measurements to source attribution, time/transport properties of fine PM, and implications for management strategies for PM{sub 2.5}; and Validate and compare key measurement methods used in this study for applicability within other PM{sub 2.5} research by DOE-FE, EPA, NARSTO, and others. During the third project quarter, the new SRI air monitoring shelter and additional instruments were installed at the site. Details include: Installation of Radiance Research M903 Nephelometer; Installation of SRI air monitoring shelter at North Birmingham Site; Relocation of instruments from SEARCH shelter to SRI shelter; Installation of Rupprecht & Patashnick 8400 Sulfate Monitor; Assembly and initial laboratory testing for particulate sulfate monitor of Harvard design; Efficiency testing of particle sizing instrument package at SRI lab; Preparation for the Eastern Supersite July measurement intensive program; and Continued monitoring with TEOM and particle sizing instruments.

  11. Ionic-Liquid-Based Heterogeneous Covalent Triazine Framework Cobalt Catalyst for the Direct Synthesis of Methyl 3-Hydroxybutyrate from Propylene Oxide.

    PubMed

    Rajendiran, Senkuttuvan; Park, Kwangho; Lee, Kwangyeol; Yoon, Sungho

    2017-06-19

    β-Hydroxy esters are considered as potential building blocks for the production of fine chemicals and potential drug molecules in various industries. Developing an efficient and recyclable catalyst for the synthesis of β-hydroxy esters is challenging. Here we report the first ionic-liquid-based heterogenized cobalt catalyst, [imidazolium-CTF][Co(CO)4], for the direct ring-opening carbonylation of propylene oxide to methyl 3-hydroxybutyrate (MHB) with 86% selectivity (>99% conversion).

  12. Dismantling the Digital Divide: A Multicultural Education Framework.

    ERIC Educational Resources Information Center

    Gorski, Paul C.

    2002-01-01

    Describes inequities in access to computers by gender and race, drawing connections between the two and discussing the use of a multicultural education approach to understanding and eliminating the digital divide. This involves such actions as critiquing technology-related inequities in the context of larger educational and social inequities,…

  13. Middle School Mathematics Students' Justification Schemes for Dividing Fractions

    ERIC Educational Resources Information Center

    Day, Melina Michele

    2010-01-01

    Three theoretical frameworks were used to guide this intervention case study: dividing fractions; sociomathematical norms, and justification. Middle school mathematics students were given the opportunity to solve partitive and measurement division of fraction word problems with different contexts. The teacher purposefully implemented a…

  14. The Learning Computer: Low Bandwidth Tool that Bridges Digital Divide

    ERIC Educational Resources Information Center

    Johnson, Russell; Kemp, Elizabeth; Kemp, Ray; Blakey, Peter

    2007-01-01

    This article reports on a project that explores strategies for narrowing the digital divide by providing a practicable e-learning option for the millions living outside the ambit of high performance computing and communication technology. The concept is introduced of a "learning computer," a low bandwidth tool that provides a simplified,…

  15. Leadership Analysis in K-12 Case Study: "Divided Loyalties"

    ERIC Educational Resources Information Center

    Alsubaie, Merfat Ayesh

    2016-01-01

    This report mainly aims to provide a critical and in-depth analysis of the K-12 Case, "Divided Loyalty" by Holy and Tartar (2004). The case recounts how the manifestation of inadequate leadership skills in a school setting could affect negatively the performance of students.

  16. Dividing Attention Lowers Children's but Increases Adults' False Memories

    ERIC Educational Resources Information Center

    Otgaar, Henry; Peters, Maarten; Howe, Mark L.

    2012-01-01

    The present study examined the impact of divided attention on children's and adults' neutral and negative true and false memories in a standard Deese/Roediger-McDermott paradigm. Children (7- and 11-year-olds; n = 126) and adults (n = 52) received 5 neutral and 5 negative Deese/Roediger-McDermott word lists; half of each group also received a…

  17. Effects of valence and divided attention on cognitive reappraisal processes.

    PubMed

    Morris, John A; Leclerc, Christina M; Kensinger, Elizabeth A

    2014-12-01

    Numerous studies have investigated the neural substrates supporting cognitive reappraisal, identifying the importance of cognitive control processes implemented by prefrontal cortex (PFC). This study examined how valence and attention affect the processes used for cognitive reappraisal by asking participants to passively view or to cognitively reappraise positive and negative images with full or divided attention. When participants simply viewed these images, results revealed few effects of valence or attention. However, when participants engaged in reappraisal, there was a robust effect of valence, with the reappraisal of negative relative to positive images associated with more widespread activation, including within regions of medial and lateral PFC. There also was an effect of attention, with more lateral PFC recruitment when regulating with full attention and more medial PFC recruitment when regulating with divided attention. Within two regions of medial PFC and one region of ventrolateral PFC, there was an interaction between valence and attention: in these regions, divided attention reduced activity during reappraisal of positive but not negative images. Critically, participants continued to report reappraisal success even during the Divided Attention condition. These results suggest multiple routes to successful cognitive reappraisal, depending upon image valence and the availability of attentional resources.

  18. The Learning Computer: Low Bandwidth Tool that Bridges Digital Divide

    ERIC Educational Resources Information Center

    Johnson, Russell; Kemp, Elizabeth; Kemp, Ray; Blakey, Peter

    2007-01-01

    This article reports on a project that explores strategies for narrowing the digital divide by providing a practicable e-learning option for the millions living outside the ambit of high performance computing and communication technology. The concept is introduced of a "learning computer," a low bandwidth tool that provides a simplified,…

  19. A School Divided: One Elementary School's Response to Education Policy

    ERIC Educational Resources Information Center

    Zoch, Melody

    2017-01-01

    This article examines how one elementary school was divided into two schools--a primary and an intermediate school--because of how policies were interpreted and enacted with regard to high-stakes testing. The grades in which students took high-stakes tests were privileged in terms of receiving monetary resources and support from staff. An emphasis…

  20. The Credit/Non-Credit Divide: Breaking Down the Wall

    ERIC Educational Resources Information Center

    Fouts, Susan; Mallory, Judy

    2010-01-01

    Programs awarding academic credit and programs awarding continuing education credit coexist on university campuses but often do not communicate or collaborate. This article explores the components of a successful program that reaches across the credit-noncredit divide to engage and serve the community. While most theoretical models are based on a…

  1. The Common Core State Standards and the Great Divide

    ERIC Educational Resources Information Center

    Wiley, Terrence G.; Rolstad, Kellie

    2014-01-01

    This article contextualizes recent developments around issues of language and the new Common Core State Standards (CCSS) in terms of the classic distinction between literates and non-literates in the Great Divide debate. Using a social practices perspective to frame the issues, the authors argue that the CCSS reiterate the debate, and reflect an…

  2. A House Divided? The Psychology of Red and Blue America

    ERIC Educational Resources Information Center

    Seyle, D. Conor; Newman, Matthew L.

    2006-01-01

    Recently it has become commonplace in America for commentators and the public to use the terms "red" and "blue" to refer to perceived cultural differences in America and American politics. Although a political divide may exist in America today, these particular terms are inaccurate and reductive. This article presents research from social…

  3. Bridging the Digital Divide in the Schools of Developing Countries

    ERIC Educational Resources Information Center

    Tiene, Drew

    2004-01-01

    The so-called "digital divide" problem, significant disparities in access to technology between the affluent and impoverished, is a global phenomenon that is most serious in the poorest parts of the world. The millions who struggle daily for enough food, clothing, housing, and transportation, are unable to afford the hardware, software and service…

  4. Agile Development & Software Architecture - Crossing the Great Divide

    DTIC Science & Technology

    2010-04-22

    University What is Architecture? Structure A Thematic Analysis System Qualities Decisions / Governance Multi-Dimensional SEI IEEE TOGAF Rozanski & Woods 12...TWITTER Hashtag #seiwebinar Crossing the Great Divide Brown , 4/22/2010 © 2010 Carnegie Mellon University Architectural Themes SEI IEEE TOGAF Rozanski...2010 © 2010 Carnegie Mellon University Structure System Qualities Decisions / Governance Multi-Dimensional Architectural Themes SEI IEEE TOGAF Rozanski

  5. Research and Practice in Education: Building Alliances, Bridging the Divide

    ERIC Educational Resources Information Center

    Coburn, Cynthia E., Ed.; Stein, Mary Kay, Ed.

    2010-01-01

    That there is a divide between research and practice is a common lament across policy-oriented disciplines, and education is no exception. Rhetoric abounds about the role research plays (or does not play) in the improvement of schools and classrooms, and policy makers push solutions that are rooted in assumptions about the way that research…

  6. Response Styles and the Rural-Urban Divide

    ERIC Educational Resources Information Center

    Thomas, Troy D.; Abts, Koen; Vander Weyden, Patrick

    2014-01-01

    This article investigates the effect of the rural-urban divide on mean response styles (RSs) and their relationships with the sociodemographic characteristics of the respondents. It uses the Representative Indicator Response Style Means and Covariance Structure (RIRSMACS) method and data from Guyana--a developing country in the Caribbean. The…

  7. Teachers in the Social Trenches: Teaching Civics in Divided Societies

    ERIC Educational Resources Information Center

    Tamir, Yuli

    2015-01-01

    This article argues that in divided societies, civic education fails to fulfill one of its most important social role: creating a more inclusive society that allows a democratic dialogue to flow across different ideological, religious, and cultural communities. This failure is grounded in two main reasons. First, civics teachers are socially and…

  8. Teachers in the Social Trenches: Teaching Civics in Divided Societies

    ERIC Educational Resources Information Center

    Tamir, Yuli

    2015-01-01

    This article argues that in divided societies, civic education fails to fulfill one of its most important social role: creating a more inclusive society that allows a democratic dialogue to flow across different ideological, religious, and cultural communities. This failure is grounded in two main reasons. First, civics teachers are socially and…

  9. Middle School Mathematics Students' Justification Schemes for Dividing Fractions

    ERIC Educational Resources Information Center

    Day, Melina Michele

    2010-01-01

    Three theoretical frameworks were used to guide this intervention case study: dividing fractions; sociomathematical norms, and justification. Middle school mathematics students were given the opportunity to solve partitive and measurement division of fraction word problems with different contexts. The teacher purposefully implemented a…

  10. Using Bloom To Bridge the WAC/WID Divide.

    ERIC Educational Resources Information Center

    Cross, Geoffrey; Wills, Katherine

    A longitudinal study combined Stephen Tsuchdi's Workaday activities with Bloom's taxonomy of educational objectives to bridge the WAC/WID (writing across the curriculum/writing in the disciplines) divide. The researchers hoped that by combining concrete activities that can be applied across disciplines with a Bloomian conceptual framework of…

  11. Fiber-optic Michelson interferometer using an optical power divider.

    PubMed

    Imai, M; Ohashi, T; Ohtsuka, Y

    1980-10-01

    A fiber-optic interferometer consisting of a multimode fiber-optical power divider was constructed in the Michelson arrangement and applied to measure a micrometer-order displacement of the vibrating object based on an optical homodyne technique. Improvement in the sensitivity of the apparatus is discussed from the viewpoint of increasing the minimum detectable beat signal.

  12. The Common Core State Standards and the Great Divide

    ERIC Educational Resources Information Center

    Wiley, Terrence G.; Rolstad, Kellie

    2014-01-01

    This article contextualizes recent developments around issues of language and the new Common Core State Standards (CCSS) in terms of the classic distinction between literates and non-literates in the Great Divide debate. Using a social practices perspective to frame the issues, the authors argue that the CCSS reiterate the debate, and reflect an…

  13. Research and Practice in Education: Building Alliances, Bridging the Divide

    ERIC Educational Resources Information Center

    Coburn, Cynthia E., Ed.; Stein, Mary Kay, Ed.

    2010-01-01

    That there is a divide between research and practice is a common lament across policy-oriented disciplines, and education is no exception. Rhetoric abounds about the role research plays (or does not play) in the improvement of schools and classrooms, and policy makers push solutions that are rooted in assumptions about the way that research…

  14. Measurement and Fair-Sharing Models for Dividing Fractions

    ERIC Educational Resources Information Center

    Gregg, Jeff; Gregg, Diana Underwood

    2007-01-01

    This article discusses two sequences of activities that were developed to support middle school students' and preservice teachers' construction of algorithms for dividing fractions. One sequence is intended to promote understanding of the common-denominator algorithm; the other sequence is intended to promote understanding of the…

  15. New Literacies at the Digital Divide: American Indian Community Computing

    ERIC Educational Resources Information Center

    Betts, J. David

    2009-01-01

    This study is about a community computing lab established by a U.S. Department of Commerce grant to bridge the Digital Divide in a rural Arizona American Indian community, a project called "Native Connection" (a pseudonym). This paper describes the process of integrating new literacies associated with a high-tech computer lab into the…

  16. Dividing Attention Lowers Children's but Increases Adults' False Memories

    ERIC Educational Resources Information Center

    Otgaar, Henry; Peters, Maarten; Howe, Mark L.

    2012-01-01

    The present study examined the impact of divided attention on children's and adults' neutral and negative true and false memories in a standard Deese/Roediger-McDermott paradigm. Children (7- and 11-year-olds; n = 126) and adults (n = 52) received 5 neutral and 5 negative Deese/Roediger-McDermott word lists; half of each group also received a…

  17. Journalism Students, Web 2.0 and the Digital Divide

    ERIC Educational Resources Information Center

    Green, Mary Elizabeth

    2009-01-01

    The purpose of this study was to find out if students were utilizing Web 2.0 applications. Since the applications in question are often employed by the media industry, the study aspired to find out if students majoring in mass communication and journalism utilized the applications more often than other students. The "digital divide" is a term used…

  18. Peculiarities of the Digital Divide in Sub-Saharan Africa

    ERIC Educational Resources Information Center

    Mutula, Stephen M.

    2005-01-01

    Purpose: Seeks to argue that the peculiarities of sub-Saharan Africa, in terms of its socio-cultural diversity, low economic development, linguistic factors, HIV/AIDS pandemic, gender discrimination, low ICT awareness and so on, demand a new model of addressing the digital divide. Design/methodology/approach: Paper largely based on literature…

  19. The Digital Divide: The Special Case of Gender

    ERIC Educational Resources Information Center

    Cooper, J.

    2006-01-01

    This paper examines the evidence for the digital divide based on gender. An overview of research published in the last 20 years draws to the conclusion that females are at a disadvantage relative to men when learning about computers or learning other material with the aid of computer-assisted software. The evidence shows that the digital divide…

  20. Journalism Students, Web 2.0 and the Digital Divide

    ERIC Educational Resources Information Center

    Green, Mary Elizabeth

    2009-01-01

    The purpose of this study was to find out if students were utilizing Web 2.0 applications. Since the applications in question are often employed by the media industry, the study aspired to find out if students majoring in mass communication and journalism utilized the applications more often than other students. The "digital divide" is a term used…

  1. Digital Divide among Youth: Socio-Cultural Factors and Implications

    ERIC Educational Resources Information Center

    Parycek, Peter; Sachs, Michael; Schossbock, Judith

    2011-01-01

    Purpose: This paper aims to examine socio-cultural differences in internet use (Digital Divide) among 14-year-old Austrian pupils, in particular usage scenarios and research competences. It is based on a paper presented at the International Association for the Development of the Information Society e-Society conference, 10-13 March 2011, Spain…

  2. The Digital Divide and Its Impact on Academic Performance

    ERIC Educational Resources Information Center

    Sun, Jerry Chih-Yuan; Metros, Susan E.

    2011-01-01

    The purpose of this article is to explore issues of the digital divide and its impact on academic performance. Research shows that proper use of technology by students increases their academic performance outcomes. In the literature review section, the authors review articles and theories based on Bennett's (2001) societal equity framework. The…

  3. From Fundamentalists to Structuralists: Bridging the Digital Divide

    ERIC Educational Resources Information Center

    Kok, Ayse

    2010-01-01

    The purpose of this literature review is to provide information about several ICT initiatives undertaken in education on a global basis in order to overcome the digital divide and summarise the findings of these initiatives. Due to the limited scope of the study, the bulk of the review mainly concerns initiatives undertaken in secondary schools,…

  4. Communication in a Divided World: Opportunities and Constraints.

    ERIC Educational Resources Information Center

    Lasswell, Harold

    Communication systems in a divided world can perpetuate tension and violence or can be instrumental in developing unity. In response to this power, communicators must focus on generating worldwide recognition of interdependence in the shaping and sharing of values. Likewise, a responsible communication policy must stimulate the invention and…

  5. A School Divided: One Elementary School's Response to Education Policy

    ERIC Educational Resources Information Center

    Zoch, Melody

    2017-01-01

    This article examines how one elementary school was divided into two schools--a primary and an intermediate school--because of how policies were interpreted and enacted with regard to high-stakes testing. The grades in which students took high-stakes tests were privileged in terms of receiving monetary resources and support from staff. An emphasis…

  6. Dismantling the Digital Divide: A Multicultural Education Framework.

    ERIC Educational Resources Information Center

    Gorski, Paul C.

    2002-01-01

    Describes inequities in access to computers by gender and race, drawing connections between the two and discussing the use of a multicultural education approach to understanding and eliminating the digital divide. This involves such actions as critiquing technology-related inequities in the context of larger educational and social inequities,…

  7. Process for preparing fine grain silicon carbide powder

    DOEpatents

    Wei, G.C.

    Finely divided silicon carbide powder is obtained by mixing colloidal silica and unreacted phenolic resin in either acetone or methanol, evaporating solvent from the obtained solution to form a gel, drying and calcining the gel to polymerize the phenolic resin therein, pyrolyzing the dried and calcined gel at a temperature in the range of 500 to 1000/sup 0/C, and reacting silicon and carbon in the pyrolyzed gel at a temperature in the range of 1550 to 1700/sup 0/C to form the powder.

  8. Process for preparing fine grain titanium carbide powder

    DOEpatents

    Janney, M.A.

    1985-03-12

    A method for preparing finely divided titanium carbide powder in which an organotitanate is reacted with a carbon precursor polymer to provide an admixture of the titanium and the polymer at a molecular level due to a crosslinking reaction between the organotitanate and the polymer. The resulting gel is dried, pyrolyzed to drive off volatile components and provide carbon. The resulting solids are then heated at an elevated temperature to convert the titanium and carbon to high-purity titanium carbide powder in a submicron size range.

  9. Process for preparing fine grain titanium carbide powder

    DOEpatents

    Janey, Mark A.

    1986-01-01

    A method for preparing finely divided titanium carbide powder in which an organotitanate is reacted with a carbon precursor polymer to provide an admixture of the titanium and the polymer at a molecular-level due to a crosslinking reaction between the organotitanate and the polymer. The resulting gel is dried, pyrolyzed to drive off volatile components and provide carbon. The resulting solids are then heated at an elevated temperature to convert the titanium and carbon to high-purity titanium carbide powder in a submicron size range.

  10. Regeneration of Hydrotreating and FCC Catalysts

    SciTech Connect

    CM Wai; JG Frye; JL Fulton; LE Bowman; LJ Silva; MA Gerber

    1999-09-30

    Hydrotreating, hydrocracking, and fluid catalytic cracking (FCC) catalysts are important components of petroleum refining processes. Hydrotreating and hydrocracking catalysts are used to improve the yield of high-quality light oil fractions from heavier crude oil and petroleum feedstocks containing high levels of impurities. FCC catalysts improve the yield of higher octane gasoline from crude oil. Residuum hydrotreating and cracking catalysts are susceptible to irreversible deactivation caused by adsorption of sulfur and by metals impurities, such as vanadium and nickel. The gradual buildup of these impurities in a hydrotreating catalyst eventually plugs the pores and deactivates it. Nickel and vanadium adversely affect the behavior of cracking catalysts, reducing product yield and quality. Replacing deactivated catalysts represents a significant cost in petroleum refining. Equally important are the costs and potential liabilities associated with treating and disposing spent catalysts. For example, recent US Environmental Protection Agency rulings have listed spent hydrotreating and hydrorefining catalysts as hazardous wastes. FCC catalysts, though more easily disposed of as road-base or as filler in asphalt and cement, are still an economic concern mainly because of the large volumes of spent catalysts generated. New processes are being considered to increase the useful life of catalysts or for meeting more stringent disposal requirements for spent catalysts containing metals. This report discusses a collaborative effort between Pacific Northwest National Laboratory (PNNL) and Phillips Petroleum, Inc., to identify promising chemical processes for removing metals adhered to spent hydrodesulfurization (HDS, a type of hydrotreating catalyst) and FCC catalysts. This study, conducted by PNNL, was funded by the US Department of Energy's Bartlesville Project Office. Fresh and spent catalysts were provided by Phillips Petroleum. The FCC catalyst was a rare-earth exchanged

  11. A Survey of Attitudinal Changes of Student Teachers in Fine Arts.

    ERIC Educational Resources Information Center

    Seiferth, Berniece B.; Samuel, Marie

    Results of a survey to determine the attitudes of student teachers toward 20 educational concepts before and after their student teaching experience are reported. The concepts were divided into three subgroups: attitudes toward interpersonal behaviors, techniques and methods, and classroom structure. Ten student teachers in fine arts as well as…

  12. The fine structure of the oocyte of bankia australis (teredinidae, bivalvia) before and after fertilization.

    PubMed

    Popham, J D

    1975-01-01

    The fine structure of the oocyte of Bankia australis is compared with that of other bivalve oocytes. It was observed that following fertilization, the microvilli changed their spatial organisation and behaviour towards sperm, the cortical granules disappeared in regions of high concentrations of supernumerary sperm, and the mitochondria apparently stated to divide.

  13. Advanced on-chip divider for monolithic microwave VCO's

    NASA Technical Reports Server (NTRS)

    Peterson, Weddell C.

    1989-01-01

    High frequency division on a monolithic circuit is a critical technology required to significantly enhance the performance of microwave and millimeter-wave phase-locked sources. The approach used to meet this need is to apply circuit design practices which are essentially 'microwave' in nature to the basically 'digital' problem of high speed division. Following investigation of several promising circuit approaches, program phase 1 culminated in the design and layout of an 8.5 GHz (Deep Space Channel 14) divide by four circuit based on a dynamic mixing divider circuit approach. Therefore, during program phase 2, an 8.5 GHz VCO with an integral divider which provides a phase coherent 2.125 GHz reference signal for phase locking applications was fabricated and optimized. Complete phase locked operation of the monolithic GaAs devices (VCO, power splitter, and dynamic divider) was demonstrated both individually and as an integrated unit. The fully functional integrated unit in a suitable test fixture was delivered to NASA for engineering data correlation. Based on the experience gained from this 8.5 GHz super component, a monolithic GaAs millimeter-wave dynamic divider for operation with an external VCO was also designed, fabricated, and characterized. This circuit, which was also delivered to NASA, demonstrated coherent division by four at an input frequency of 24.3 GHz. The high performance monolithic microwave VCO with a coherent low frequency reference output described in this report and others based on this technology will greatly benefit advanced communications systems in both the DoD and commercial sectors. Signal processing and instrumentation systems based on phase-locking loops will also attain enhanced performance at potentially reduced cost.

  14. Preparation and characterization of Rh catalyst supported on nanoporous alumina for the ethylene hydroformylation.

    PubMed

    Kim, You Jung; Joo, Ji Bong; Kim, Hui Chan; Yi, Jongheop

    2010-01-01

    Nanoporous gamma-aluminas were prepared by a sol-gel method with and without surfactant, and characterized by nitrogen adsorption-desorption, transmission electron microscopy (TEM), X-ray diffraction (XRD) and temperature programmed reduction (TPR). The resulting materials were applied to Rh catalyst supports for the ethylene hydroformylation. The ordered nanoporous alumina (A-1) which was prepared using surfactant, showed well-developed pore structures with high surface area. Rh catalyst supported on A-1 alumina (Rh/A-1) exhibited higher catalytic activity in the ethylene hydroformylation than other Rh catalysts. It is believed that the high catalytic performance of Rh/A-1 resulted from the well-developed pore structure with high surface area of ordered nanoporous A-1 and consequently finely dispersed Rh particle on the surface of gamma-alumina support.

  15. Catalytic and electrocatalytic oxidation of ethanol over palladium-based nanoalloy catalysts.

    PubMed

    Yin, Jun; Shan, Shiyao; Ng, Mei Shan; Yang, Lefu; Mott, Derrick; Fang, Weiqin; Kang, Ning; Luo, Jin; Zhong, Chuan-Jian

    2013-07-23

    The control of the nanoscale composition and structure of alloy catalysts plays an important role in heterogeneous catalysis. This paper describes novel findings of an investigation for Pd-based nanoalloy catalysts (PdCo and PdCu) for ethanol oxidation reaction (EOR) in gas phase and alkaline electrolyte. Although the PdCo catalyst exhibits a mass activity similar to Pd, the PdCu catalyst is shown to display a much higher mass activity than Pd for the electrocatalytic EOR in alkaline electrolyte. This finding is consistent with the finding on the surface enrichment of Pd on the alloyed PdCu surface, in contrast to the surface enrichment of Co in the alloyed PdCo surface. The viability of C-C bond cleavage was also probed for the PdCu catalysts in both gas-phase and electrolyte-phase EOR. In the gas-phase reaction, although the catalytic conversion rate for CO2 product is higher over Pd than PdCu, the nanoalloy PdCu catalyst appears to suppress the formation of acetic acid, which is a significant portion of the product in the case of pure Pd catalyst. In the alkaline electrolyte, CO2 was detected from the gas phase above the electrolyte upon acid treatment following the electrolysis, along with traces of aldehyde and acetic acid. An analysis of the electrochemical properties indicates that the oxophilicity of the base metal alloyed with Pd, in addition to the surface enrichment of metals, may have played an important role in the observed difference of the catalytic and electrocatalytic activities. In comparison with Pd alloyed with Co, the results for Pd alloyed with Cu showed a more significant positive shift of the reduction potential of the oxygenated Pd species on the surface. These findings have important implications for further fine-tuning of the Pd nanoalloys in terms of base metal composition toward highly active and selective catalysts for EOR.

  16. Catalyst containing oxygen transport membrane

    DOEpatents

    Lane, Jonathan A.; Wilson, Jamie R.; Christie, Gervase Maxwell; Petigny, Nathalie; Sarantopoulos, Christos

    2017-02-07

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a microstructure exhibiting substantially uniform pore size distribution as a result of using PMMA pore forming materials or a bi-modal particle size distribution of the porous support layer materials. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  17. Microreactor for efficient catalyst evaluation

    NASA Astrophysics Data System (ADS)

    Besser, Ronald S.; Ouyang, Sean; Surangalikar, Harshal; Prevot, Michelle

    2001-09-01

    This paper describes ongoing work in the development of microreactor-based systems for applications in the chemical process industry. The microreactors discussed here are formed from silicon using robust micromachining processes to produce devices with micrometer-scale fluidic structures including passageways for the introduction and removal of gases, and a reaction zone with a thin-film catalyst. We describe experiments done to characterize these reactors for use as development tools for industrial catalytic processes in terms of catalyst screening, acquisition of rate laws, and determination of optimal process conditions. The system studied here, the reaction of a cyclic olefin (cyclohexene) with hydrogen in the presence of platinum catalyst, is a model for industrially important catalytic hydrogenation and dehydrogenation reactions.

  18. Catalysts for improved fuel processing

    SciTech Connect

    Borup, R.L.; Inbody, M.A.

    2000-09-01

    This report covers our technical progress on fuel processing catalyst characterization for the specific purpose of hydrogen production for proton-exchange-membrane (PEM) fuel cells. These development efforts support DOE activities in the development of compact, transient capable reformers for on-board hydrogen generation starting from candidate fuels. The long-term objective includes increased durability and lifetime, in addition to smaller volume, improved performance, and other specifications required meeting fuel processor goals. The technical barriers of compact fuel processor size, transient capability, and compact, efficient thermal management all are functions of catalyst performance. Significantly, work at LANL now tests large-scale fuel processors for performance and durability, as influenced by fuels and fuel constituents, and complements that testing with micro-scale catalyst evaluation which is accomplished under well controlled conditions.

  19. Catalyst containing oxygen transport membrane

    DOEpatents

    Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

    2012-12-04

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  20. Hydrogen adsorption on two catalysts for the ortho- to parahydrogen conversion: Cr-doped silica and ferric oxide gel.

    PubMed

    Hartl, Monika; Gillis, Robert Chad; Daemen, Luke; Olds, Daniel P; Page, Katherine; Carlson, Stefan; Cheng, Yongqiang; Hügle, Thomas; Iverson, Erik B; Ramirez-Cuesta, A J; Lee, Yongjoong; Muhrer, Günter

    2016-06-29

    Molecular hydrogen exists in two spin-rotation coupled states: parahydrogen and orthohydrogen. Due to the variation of energy with rotational level, the occupation of ortho- and parahydrogen states is temperature dependent, with parahydrogen being the dominant species at low temperatures. The equilibrium at 20 K (99.8% parahydrogen) can be reached by natural conversion only after a lengthy process. With the use of a suitable catalyst, this process can be shortened significantly. Two types of commercial catalysts currently being used for ortho- to parahydrogen conversion are: iron(iii) oxide (Fe2O3, IONEX®), and chromium(ii) oxide doped silica catalyst (CrO·SiO2, OXISORB®). We investigate the interaction of ortho- and parahydrogen with the surfaces of these ortho-para conversion catalysts using neutron vibrational spectroscopy. The catalytic surfaces have been characterized using X-ray absorption fine structure (XAFS) and X-ray/neutron pair distribution function measurements.

  1. Novel Fischer-Tropsch catalysts. [DOE patent

    DOEpatents

    Vollhardt, K.P.C.; Perkins, P.

    Novel compounds are described which are used as improved Fischer-Tropsch catalysts particularly for the conversion of CO + H/sub 2/ to gaseous and liquid hydrocarbons at milder conditions than with prior catalysts.

  2. Catalyst for Decomposition of Nitrogen Oxides

    NASA Technical Reports Server (NTRS)

    Schryer, David R. (Inventor); Jordan, Jeffrey D. (Inventor); Akyurtlu, Ates (Inventor); Akyurtlu, Jale (Inventor)

    2015-01-01

    This invention relates generally to a platinized tin oxide-based catalyst. It relates particularly to an improved platinized tin oxide-based catalyst able to decompose nitric oxide to nitrogen and oxygen without the necessity of a reducing gas.

  3. Catalysts for carbon and coal gasification

    DOEpatents

    McKee, Douglas W.; Spiro, Clifford L.; Kosky, Philip G.

    1985-01-01

    Catalyst for the production of methane from carbon and/or coal by means of catalytic gasification. The catalyst compostion containing at least two alkali metal salts. A particulate carbonaceous substrate or carrier is used.

  4. Development of ferrocene burning rate catalysts

    NASA Astrophysics Data System (ADS)

    Zhang, Ren; Li, Jianhua; Weng, Wujun

    1994-06-01

    In this paper, a comprehensive survey of the development of research on the ferrocene burning rate catalysts in the past thirty years was made. The development trend of ferrocene catalysts in the future was also pointed out.

  5. 36 CFR 910.35 - Fine arts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Fine arts. 910.35 Section 910... DEVELOPMENT AREA Standards Uniformly Applicable to the Development Area § 910.35 Fine arts. Fine arts... of art which are appropriate for the development. For information and guidance, a...

  6. 36 CFR 910.35 - Fine arts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Fine arts. 910.35 Section 910... DEVELOPMENT AREA Standards Uniformly Applicable to the Development Area § 910.35 Fine arts. Fine arts... of art which are appropriate for the development. For information and guidance, a...

  7. 36 CFR 910.35 - Fine arts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Fine arts. 910.35 Section 910... DEVELOPMENT AREA Standards Uniformly Applicable to the Development Area § 910.35 Fine arts. Fine arts... of art which are appropriate for the development. For information and guidance, a...

  8. Considering Fine Art and Picture Books

    ERIC Educational Resources Information Center

    Serafini, Frank

    2015-01-01

    There has been a close association between picturebook illustrations and works of fine art since the picturebook was first conceived, and many ways these associations among works of fine art and picturebook illustrations and design play out. To make sense of all the various ways picturebook illustrations are associated with works of fine art,…

  9. Single-atom catalysts: a new frontier in heterogeneous catalysis.

    PubMed

    Yang, Xiao-Feng; Wang, Aiqin; Qiao, Botao; Li, Jun; Liu, Jingyue; Zhang, Tao

    2013-08-20

    Supported metal nanostructures are the most widely used type of heterogeneous catalyst in industrial processes. The size of metal particles is a key factor in determining the performance of such catalysts. In particular, because low-coordinated metal atoms often function as the catalytically active sites, the specific activity per metal atom usually increases with decreasing size of the metal particles. However, the surface free energy of metals increases significantly with decreasing particle size, promoting aggregation of small clusters. Using an appropriate support material that strongly interacts with the metal species prevents this aggregation, creating stable, finely dispersed metal clusters with a high catalytic activity, an approach industry has used for a long time. Nevertheless, practical supported metal catalysts are inhomogeneous and usually consist of a mixture of sizes from nanoparticles to subnanometer clusters. Such heterogeneity not only reduces the metal atom efficiency but also frequently leads to undesired side reactions. It also makes it extremely difficult, if not impossible, to uniquely identify and control the active sites of interest. The ultimate small-size limit for metal particles is the single-atom catalyst (SAC), which contains isolated metal atoms singly dispersed on supports. SACs maximize the efficiency of metal atom use, which is particularly important for supported noble metal catalysts. Moreover, with well-defined and uniform single-atom dispersion, SACs offer great potential for achieving high activity and selectivity. In this Account, we highlight recent advances in preparation, characterization, and catalytic performance of SACs, with a focus on single atoms anchored to metal oxides, metal surfaces, and graphene. We discuss experimental and theoretical studies for a variety of reactions, including oxidation, water gas shift, and hydrogenation. We describe advances in understanding the spatial arrangements and electronic

  10. Monolithic catalyst catalytic converter with catalyst holding expansible retainer ring

    SciTech Connect

    Isogai, K.; Koga, I.; Ohmori, N.; Okamoto, M.; Takeuchi, M.; Takita, N.; Tobi, N.

    1984-05-15

    A catalytic converter includes a tubular casing within which is held a monolithic catalyst body which is generally of a columnar shape. The ends of the monolithic catalyst body are each engaged with a cushion ring, and each cushion ring is engaged with a retainer ring therefor, which is substantially axially fixed within the casing near to an end thereof. The monolithic catalyst body is supported within the casing by axial compressive force present between the retainer rings on the outside, the cushion rings between the retainer rings, and the monolithic catalyst body between the cushion rings. At least one of the retainer rings is formed with a break in a part of its circumference, the two free ends of the retainer ring on the two sides of the break being movable with distortion of the retainer ring through a certain distance, according to changes of temperature of the retainer ring, with respect to one another in the mutual relative direction which causes the overall circumference of the retainer ring to be diminished, so that expansion of the retainer ring when it heats up is adsorbed, and the retainer ring is not subject to kinking or folding when the catalytic converter operates in the hot condition.

  11. On-line regeneration of hydrodesulfurization catalyst

    DOEpatents

    Preston, Jr., John L.

    1980-01-01

    A hydrotreating catalyst is regenerated as it concurrently hydrotreats a hydrocarbon fuel by introducing a low concentration of oxygen into the catalyst bed either continuously or periodically. At low oxygen concentrations the carbon deposits on the catalyst are burned off without harming the catalyst and without significantly affecting the hydrotreating process. In a preferred embodiment the hydrotreating process is hydrodesulfurization, and regenerating is done periodically with oxygen concentrations between 0.1 and 0.5 volume percent.

  12. Magnetically retrievable catalysts for organic synthesis.

    PubMed

    Baig, R B Nasir; Varma, Rajender S

    2013-01-28

    The use of magnetic nanoparticles (MNPs) as a catalyst support in organic synthesis is summarized. The recovery of expensive catalysts after catalytic reaction and reusing them without losing their activity is an essential feature in the sustainable process development. The aim of this article is to highlight the progress in the synthesis and catalytic applications of magnetic catalysts in organic synthesis. The heterogenization of the catalyst using magnetic nanoparticles allows it to be recovered and reused using an external magnet.

  13. Experts reveal catalyst-selection methodologies

    SciTech Connect

    1996-10-14

    Refining catalyst selection procedure were discussed in detail at Oil and Gas Journal`s International Catalyst Conference, Feb. 1--2, in Houston. Marathon Oil Co.`s James P. Wick revealed details of Marathon`s program for review and optimization of fluid catalytic cracking (FCC) and hydrotreating catalysts. And renowned FCC expert Del Tolen outlined a step-by-step procedure for choosing an FCC catalyst. The paper describes Marathon`s program and Tolen`s selection process.

  14. Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

    DOEpatents

    Gangwal, Santosh; Jothimurugesan, Kandaswamy

    1999-01-01

    A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption processes, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gasses from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or "passivating" the heavy metals on the spent FCC catalyst as an intermediate step.

  15. Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

    DOEpatents

    Gangwal, S.; Jothimurugesan, K.

    1999-07-27

    A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption process, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gases from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or passivating the heavy metals on the spent FCC catalyst as an intermediate step.

  16. Silver doped catalysts for treatment of exhaust

    DOEpatents

    Park, Paul Worn; Hester, Virgil Raymond; Ragle, Christie Susan; Boyer, Carrie L.

    2009-06-02

    A method of making an exhaust treatment element includes washcoating a substrate with a slurry that includes a catalyst support material. At least some of the catalyst support material from the slurry may be transferred to the substrate, and silver metal (Ag) is dispersed within the catalyst support material.

  17. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853, P-93...

  18. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853, P-93...

  19. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853, P-93...

  20. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853, P-93...