Syngas Production from Catalytic CO2 Reforming of CH4 over CaFe2O4 Supported Ni and Co Catalysts: Full Factorial Design Screening

Directory of Open Access Journals (Sweden)

M. Anwar Hossain

2018-01-01

Full Text Available In this study, the potential of dry reforming reaction over CaFe2O4 supported Ni and Co catalysts were investigated. The Co/CaFe2O4 and Ni/CaFe2O4 catalysts were synthesized using wet impregnation method by varying the metal loading from 5-15 %. The synthesized catalysts were tested in methane dry reforming reaction at atmospheric pressure and reaction temperature ranged 700-800 oC. The catalytic performance of the catalysts based on the initial screening is ranked as 5%Co/CaFe2O4 < 10%Co/CaFe2O4 < 5%Ni/CaFe2O4 < 10%Ni/CaFe2O4 according to their performance. The Ni/CaFe2O4 catalyst was selected for further investigation using full factorial design of experiment. The interaction effects of three factors namely metal loading (5-15 %, feed ratio (0.4-1.0, and reaction temperature (700-800 oC were evaluated on the catalytic activity in terms of CH4 and CO2 conversion as well as H2 and CO yield. The interaction between the factors showed significant effects on the catalyst performance at metal loading, feed ratio and reaction temperature of 15 %, 1.0, and 800 oC. respectively. The 15 wt% Ni/CaFe2O4 was subsequently characterized by Thermogravimetric (TGA, X-ray Diffraction (XRD, Field Emission Scanning Electron Microscopy (FESEM, Energy Dispersive X-ray Spectroscopy (EDX, X-ray Photoelectron Spectroscopy (XPS, N2-physisorption, Temperature Programmed Desorption (TPD-NH3, TPD-CO2, and Fourier Transform Infra Red (FTIR to ascertain its physiochemical properties.  This study demonstrated that the CaFe2O4 supported Ni catalyst has a good potential to be used for syngas production via methane dry reforming. Copyright © 2018 BCREC Group. All rights reserved Received: 5th May 2017; Revised: 8th August 2017; Accepted: 9th August 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Hossain, M.A., Ayodele, B.V., Cheng, C.K., Khan, M.R. (2018. Syngas Production from Catalytic CO2 Reforming of CH4 over CaFe2O4 Supported

Support screening studies on the hydrogenation of levulinic acid to γ‐valerolactone in water using RU catalysts

NARCIS (Netherlands)

Piskun, Anna; Winkelman, Jozef G M; Tang, Zhenchen; Heeres, Hero Jan

2016-01-01

γ-Valerolactone (GVL) has been identified as a sustainable platform chemical for the production of carbon-based chemicals. Here we report a screening study on the hydrogenation of levulinic acid (LA) to GVL in water using a wide range of ruthenium supported catalysts in a batch set-up (1 wt. % Ru,

Bifunctional cobalt F-T catalysts

Energy Technology Data Exchange (ETDEWEB)

Miller, J.G.; Coughlin, P.K.; Yang, C.L.; Rabo, J.A.

1986-03-01

Results on the catalytic screening of Fischer-Tropsch catalysts containing shape selective components are reported. Catalysts consist of promoted cobalt intimately contacted with Union Carbide molecular sieves and were tested using a Berty type internally recycled reactor. Methods of preparation, promoters and shape selective components were varied and aimed at improving catalyst performance. Catalysts were developed demonstrating high C/sub 5/ + yields with high olefin content and low methane production while maintaining stability under both low and high H/sub 2/:CO ratio conditions.

Bulk-surface relationship of an electronic structure for high-throughput screening of metal oxide catalysts

International Nuclear Information System (INIS)

Kweun, Joshua Minwoo; Li, Chenzhe; Zheng, Yongping; Cho, Maenghyo; Kim, Yoon Young; Cho, Kyeongjae

2016-01-01

Graphical abstract: - Highlights: • Bulk-surface relationship was predicted by the ligand field nature of metal oxides. • Antibonding and bonding d-bands occupancy clarified the bulk-surface relationship. • Different surface relaxations were explained by the bulk electronic structures. • Transition from the bulk to the surface state was simulated by oxygen adsorption. - Abstract: Designing metal-oxides consisting of earth-abundant elements has been a crucial issue to replace precious metal catalysts. To achieve efficient screening of metal-oxide catalysts via bulk descriptors rather than surface descriptors, we investigated the relationship between the electronic structure of bulk and that of the surface for lanthanum-based perovskite oxides, LaMO_3 (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu). Through density functional theory calculations, we examined the d-band occupancy of the bulk and surface transition-metal atoms (n_B_u_l_k and n_S_u_r_f) and the adsorption energy of an oxygen atom (E_a_d_s) on (001), (110), and (111) surfaces. For the (001) surface, we observed strong correlation between the n_B_u_l_k and n_S_u_r_f with an R-squared value over 94%, and the result was interpreted in terms of ligand field splitting and antibonding/bonding level splitting. Moreover, the E_a_d_s on the surfaces was highly correlated with the n_B_u_l_k with an R-squared value of more than 94%, and different surface relaxations could be explained by the bulk electronic structure (e.g., LaMnO_3 vs. LaTiO_3). These results suggest that a bulk-derived descriptor such as n_B_u_l_k can be used to screen metal-oxide catalysts.

Novel metalloporphyrin catalysts for the oxidation of hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Showalter, M.C.; Nenoff, T.M.; Shelnutt, J.A.

1996-11-01

Work was done for developing biomimetic oxidation catalysts. Two classes of metalloporphyrin catalysts were studied. The first class of catalysts studied were a novel series of highly substituted metalloporphyrins, the fluorinated iron dodecaphenylporphyrins. These homogeneous metalloporphyrin catalysts were screened for activity as catalysts in the oxidation of hydrocarbons by dioxygen. Results are discussed with respect to catalyst structural features. The second type of catalysts studied were heterogeneous catalysts consisting of metalloporphyrins applied to inorganic supports. Preliminary catalytic testing results with these materials are presented.

Evaluation of AECL catalysts for hydrogen fuel-cell applications. Paper no. IGEC-1-073

International Nuclear Information System (INIS)

Li, J.; Suppiah, S.; Li, H.; Kutchcoskie, K.J.; Strikwerda, S.

2005-01-01

AECL has been engaged in the promotion of the nuclear-hydrogen economy, which envisions that hydrogen fuel cells will generate power using hydrogen as fuel produced by nuclear energy. Since AECL's catalysts developed for the production, upgrading and detritiation of heavy water are very similar to commercial fuel-cell catalysts, a program was initiated to evaluate AECL catalysts for fuel-cell applications. As a first step in this effort, a half-cell test facility was set up to characterize the performance of catalysts for hydrogen fuel cells. This paper outlines the results obtained from cathodic reduction of oxygen in a 0.5 M sulphuric acid solution on a rotating disc electrode at 65 o C. The performance of the catalysts was characterized using standard electrochemical methods including cyclic voltammetry, Voltammogram/Tafel plots and short-term stability plots. Several monometallic Pt and Pt-based bimetallic catalysts were tested and compared with a commercially available catalyst for fuel-cell applications. AECL's monometallic Pt catalysts showed comparable or better activities than commercial catalysts with similar Pt loading. An AECL Pt-based bimetallic catalyst has shown superior performance to a monometallic Pt catalyst with similar Pt loading. Evaluation of various catalyst formulations is ongoing on the half-cell facility at AECL. Further investigation of promising catalysts identified from half-cell test is also being carried out in single fuel cell on test stations under normal fuel-cell operating conditions. (author)

High throughput experimentation for the discovery of new catalysts

International Nuclear Information System (INIS)

Thomson, S.; Hoffmann, C.; Johann, T.; Wolf, A.; Schmidt, H.-W.; Farrusseng, D.; Schueth, F.

2002-01-01

Full text: The use of combinatorial chemistry to obtain new materials has been developed extensively by the pharmaceutical and biochemical industries, but such approaches have been slow to impact on the field of heterogeneous catalysis. The reasons for this lie in with difficulties associated in the synthesis, characterisation and determination of catalytic properties of such materials. In many synthetic and catalytic reactions, the conditions used are difficult to emulate using High Throughput Experimentation (HTE). Furthermore, the ability to screen these catalysts simultaneously in real time, requires the development and/or modification of characterisation methods. Clearly, there is a need for both high throughput synthesis and screening of new and novel reactions, and we describe several new concepts that help to achieve these goals. Although such problems have impeded the development of combinatorial catalysis, the fact remains that many highly attractive processes still exist for which no suitable catalysts have been developed. The ability to decrease the tiFme needed to evaluate catalyst is therefore essential and this makes the use of high throughput techniques highly desirable. In this presentation we will describe the synthesis, catalytic testing, and novel screening methods developed at the Max Planck Institute. Automated synthesis procedures, performed by the use of a modified Gilson pipette robot, will be described, as will the development of two 16 and 49 sample fixed bed reactors and two 25 and 29 sample three phase reactors for catalytic testing. We will also present new techniques for the characterisation of catalysts and catalytic products using standard IR microscopy and infrared focal plane array detection, respectively

Screening of Catalysts for Hydrodeoxygenation of Phenol as Model Compound for Bio-oil

DEFF Research Database (Denmark)

Mortensen, Peter Mølgaard; Grunwaldt, Jan-Dierk; Jensen, Peter Arendt

2013-01-01

Four groups of catalysts have been tested for hydrodeoxygenation (HDO) of phenol as a model compound of bio-oil, including: oxide catalysts, methanol synthesis catalysts, reduced noble metal catalysts, and reduced non-noble metal catalysts. In total 23 different catalysts were tested at 100 bar H2...... and 275 °C in a batch reactor. The experiments showed that none of the tested oxides and methanol synthesis catalysts had any significant activity for phenol HDO at the given conditions, which were linked to their inability to hydrogenate the phenol. HDO of phenol over reduced metal catalysts could...... on a carbon support, but more active than the carbon supported noble metal catalysts when supported on ZrO2. This observation indicates that the nickel based catalysts require a metal oxide as carrier on which the activation of the phenol for the hydrogenation can take place through heterolytic dissociation...

Plated nickel wire mesh makes superior catalyst bed

Science.gov (United States)

Sill, M.

1965-01-01

Porous nickel mesh screen catalyst bed produces gas evolution in hydrogen peroxide thrust chambers used for attitude control of space vehicles. The nickel wire mesh disks in the catalyst bed are plated in rugose form with a silver-gold coating.

Chemiluminescence analyzer of NOx as a high-throughput screening tool in selective catalytic reduction of NO

International Nuclear Information System (INIS)

Oh, Kwang Seok; Woo, Seong Ihl

2011-01-01

A chemiluminescence-based analyzer of NO x gas species has been applied for high-throughput screening of a library of catalytic materials. The applicability of the commercial NO x analyzer as a rapid screening tool was evaluated using selective catalytic reduction of NO gas. A library of 60 binary alloys composed of Pt and Co, Zr, La, Ce, Fe or W on Al 2 O 3 substrate was tested for the efficiency of NO x removal using a home-built 64-channel parallel and sequential tubular reactor. The NO x concentrations measured by the NO x analyzer agreed well with the results obtained using micro gas chromatography for a reference catalyst consisting of 1 wt% Pt on γ-Al 2 O 3 . Most alloys showed high efficiency at 275 °C, which is typical of Pt-based catalysts for selective catalytic reduction of NO. The screening with NO x analyzer allowed to select Pt-Ce (X) (X=1–3) and Pt–Fe (2) as the optimal catalysts for NO x removal: 73% NO x conversion was achieved with the Pt–Fe (2) alloy, which was much better than the results for the reference catalyst and the other library alloys. This study demonstrates a sequential high-throughput method of practical evaluation of catalysts for the selective reduction of NO.

From 5-Hydroxymethylfurfural (HMF) to Polymer Precursors : Catalyst Screening Studies on the Conversion of 1,2,6-hexanetriol to 1,6-hexanediol

NARCIS (Netherlands)

Buntara, Teddy; Noel, Sébastien; Phua, Pim Huat; Melián-Cabrera, Ignacio; Vries, Johannes G. de; Heeres, Hero J.

1,6-hexanediol (1) is an important polymer precursor for the polyester industry. In this paper, exploratory catalyst screening studies on the synthesis of 1 from 1,2,6-hexanetriol (2) are described via two different routes. The latter is available by a two-step procedure from 5-hydroxymethylfurfural

Catalyst study for the plasma exhaust purification process

International Nuclear Information System (INIS)

Chabot, J.; Sannier, J.

1990-01-01

Several catalysts available from commercial sources have been screened to find out specific catalysts which allow complete methane oxidation and ammonia decomposition at temperature as low as possible in order to minimize tritium loss by permeation through processing equipment walls. Afterwards, an extended kinetic investigation has been performed on the best catalysts to achieve the data necessary to unit calculations. For methane oxidation, a palladium on alumina catalyst shows a very satisfactory low-temperature efficiency while a non-precious metal catalyst made of nickel oxide and alumina was found to be the more efficient for ammonia decomposition

CO methanation over supported bimetallic Ni-Fe catalysts: From computational studies towards catalyst optimization

DEFF Research Database (Denmark)

Kustov, Arkadii; Frey, Anne Mette; Larsen, Kasper Emil

2007-01-01

with compositions 25Fe75Ni and 50Fe50Ni showed significantly better activity and in some cases also a higher selectivity to methane compared with the traditional monometallic Ni and Fe catalysts. A catalyst with composition 25Fe75Ni was found to be the most active in CO hydrogenation for the MgAl2O4 support at low...... metal loadings. At high metal concentrations, the maximum for the methanation activity was found for catalysts with composition 50Ni50Fe both on the MgAl2O4 and Al2O3 supports. This difference can be attributed to a higher reducibility of the constituting metals with increasing metal concentration......DFT calculations combined with a computational screening method have previously shown that bimetallic Ni-Fe alloys should be more active than the traditional Ni-based catalyst for CO methanation. That was confirmed experimentally for a number of bimetallic Ni-Fe catalysts supported on MgAl2O4. Here...

Evaluation of malt spent rootlets biochar as catalyst for biodiesel production.

Science.gov (United States)

Pantiora, Dimitra

2014-05-01

Evaluation of malt spent rootlets biochar as catalyst for biodiesel production. Dimitra Pantiora1, Hrissi K. Karapanagioti1, Ioannis D. Manariotis2, Alexis Lycourghiotis1, Christos Kordulis1,3 (1) University of Patras, Department of Chemistry, GR 26500, Patras, Greece, (2) University of Patras, Department of Civil Engineering, Patras, Greece, (3) Institute of Chemical Engineering Science (FORTH/ ICE-HT), Stadiou Str., Platani, GR 26500, Patras, Greece Biodiesel is an attractive renewable fuel, environmentally friendly, and can readily be synthesized from the triglycerides found in animal fats and vegetable oils. It can be used in existing engines. Biodiesel consists of fatty acid alkyl esters. Conversion of triglycerides to biodiesel fuel is commonly achieved through a series of transesterification reactions involving the reaction of an alkoxy group of an ester (i.e., mono-, di-, or triglyceride) with that of a small alcohol (usually methanol). This reaction is traditionally catalyzed by homogeneous catalysts, such as bases or mineral acids. Basic catalysts have been proved to be much more active than acidic ones. However, due to environmental (waste water) and economic concerns (catalyst separation and product and by-product cleaning), heterogeneous catalysts are much more desirable. In the present study we have evaluated the use of biochar, produced from malt spent rootlets, as a potential basic catalyst, for transesterification of triglycerides using triacetin as a probe molecule. The biochar used in this study was prepared by heating malt spent rootlets in an oxygen-limited environment. It is a carbon rich material, containing 66% C, 22% O, 0.45% Mg, 0.86% Si, 5.7% K, 1.5% Cl, 0.61% Ca, and 2.4% P. Aqueous suspension of this material equilibrates at pH= 10. This is probably due to high K content. Furthermore, it exhibits high specific surface area (SSA= 183 m2g-1). The above described characteristics make this material very promising catalyst for

Catalyst-Free Biodiesel Production Methods: A Comparative Technical and Environmental Evaluation

Directory of Open Access Journals (Sweden)

Oseweuba Valentine Okoro

2018-01-01

Full Text Available In response to existing global focus on improved biodiesel production methods via highly efficient catalyst-free high temperature and high pressure technologies, this study considered the comparative study of catalyst-free technologies for biodiesel production as an important research area. In this study, therefore, catalyst-free integrated subcritical lipid hydrolysis and supercritical esterification and catalyst-free one step supercritical transesterification processes for biodiesel production have been evaluated via undertaking straight forward comparative energetic and environmental assessments. Energetic comparisons were undertaken after heat integration was performed since energy reduction has favourable effects on the environmental performance of chemical processes. The study confirmed that both processes are capable of producing biodiesel of high purity with catalyst-free integrated subcritical lipid hydrolysis and supercritical esterification characterised by a greater energy cost than catalyst-free one step supercritical transesterification processes for an equivalent biodiesel productivity potential. It was demonstrated that a one-step supercritical transesterification for biodiesel production presents an energetically more favourable catalyst-free biodiesel production pathway compared to the integrated subcritical lipid hydrolysis and supercritical esterification biodiesel production process. The one-step supercritical transesterification for biodiesel production was also shown to present an improved environmental performance compared to the integrated subcritical lipid hydrolysis and supercritical esterification biodiesel production process. This is because of the higher potential environment impact calculated for the integrated subcritical lipid hydrolysis and supercritical esterification compared to the potential environment impact calculated for the supercritical transesterification process, when all material and energy flows are

Walkthrough screening evaluation field guide

International Nuclear Information System (INIS)

Eder, S.J.; Eli, M.W.; Salmon, M.W.

1993-11-01

The US Department of Energy (DOE) has a large inventory of existing facilities. Many of these facilities were not designed and constructed to current natural phenomena hazard (NPH) criteria. The NPH events include earthquakes, extreme winds and tornadoes, and floods. DOE Order 5480.28 establishes policy and requirements for NPH mitigation for DOE facilities. DOE is conducting a multiyear project to develop evaluation guidelines for assessing the condition and determining the need for upgrades at DOE facilities. One element of the NPH evaluation guidelines' development involves the existing systems and components at DOE facilities. This effort is described in detail in a cited reference. In the interim period prior to availability of the final guidelines, DOE facilities are encouraged to implement an NPH walk through screening evaluation process by which systems and components that need attention can be rapidly identified. Guidelines for conducting the walk through screening evaluations are contained herein. The result of the NPH walk through screening evaluation should be a prioritized list of systems and components that need further action. Simple and inexpensive fixes for items identified in the walk through as marginal or inadequate should be implemented without further study. By implementing an NPH walk through screening evaluation, DOE facilities may realize significant reduction in risk from NPH in the short term

Catalyst evaluation for oxygen reduction reaction in concentrated phosphoric acid at elevated temperatures

Science.gov (United States)

Hu, Yang; Jiang, Yiliang; Jensen, Jens Oluf; Cleemann, Lars N.; Li, Qingfeng

2018-01-01

Phosphoric acid is the common electrolyte for high-temperature polymer electrolyte fuel cells (HT-PEMFCs) that have advantages such as enhanced CO tolerance and simplified heat and water management. The currently used rotating disk electrode technique is limited to tests in dilute solutions at low temperatures and hence is not suitable for catalyst evaluation for HT-PEMFCs. In this study, we have designed and constructed a half-cell setup to measure the intrinsic activities of catalysts towards the oxygen reduction reaction (ORR) in conditions close to HT-PEMFC cathodes. By optimization of the hydrophobic characteristics of electrodes and the catalyst layer thickness, ORR activities of typical Pt/C catalysts are successfully measured in concentrated phosphoric acid at temperatures above 100 °C. In terms of mass-specific activities, the catalyst exhibits about two times higher activity in the half-cell electrode than that observed in fuel cells, indicating the feasibility of the technique as well as the potential for further improvement of fuel cell electrode performance.

Towards the computational design of solid catalysts

DEFF Research Database (Denmark)

Nørskov, Jens Kehlet; Bligaard, Thomas; Rossmeisl, Jan

2009-01-01

Over the past decade the theoretical description of surface reactions has undergone a radical development. Advances in density functional theory mean it is now possible to describe catalytic reactions at surfaces with the detail and accuracy required for computational results to compare favourably...... with experiments. Theoretical methods can be used to describe surface chemical reactions in detail and to understand variations in catalytic activity from one catalyst to another. Here, we review the first steps towards using computational methods to design new catalysts. Examples include screening for catalysts...

Catalysts Efficiency Evaluation by using CC Analysis Test

Directory of Open Access Journals (Sweden)

Arina Negoitescu

2011-10-01

Full Text Available The study emphasizes the necessity of the catalysts efficiency testing. Diagnosis systems using lambda probes are based on the capacity of the catalyst oxygen storage. Comparing the lambda probe signals upstream and downstream of catalyst provides an indication on catalyst activity, although the correlation between oxygen storage capacity and catalyst efficiency is still difficult. Diagnosis for the 1.4 Renault Clio Symbol was accomplished in the Road Vehicles Lab at the Politehnica University of Timisoara using AVL Dicom 4000. The tests showed that the engine worked with lean mixture being necessary a fuel mixture correction calculated by the control unit ECU. A compensation of 0.14 % vol is required for the engine correct operation and emissions integration within permissible limits

Thin Film Catalyst Layers for Direct Methanol Fuel Cells

Science.gov (United States)

Witham, C. K.; Chun, W.; Ruiz, R.; Valdez, T. I.; Narayanan, S. R.

2000-01-01

One of the primary obstacles to the widespread use of the direct methanol fuel cell (DMFC) is the high cost of the catalyst. Therefore, reducing the catalyst loading well below the current level of 8-12 mg/cm 2 would be important to commercialization. The current methods for preparation of catalyst layers consisting of catalyst, ionomer and sometimes a hydrophobic additive are applied by either painting, spraying, decal transfer or screen printing processes. Sputter deposition is a coating technique widely used in manufacturing and therefore particularly attractive. In this study we have begun to explore sputtering as a method for catalyst deposition. Present experiments focus on Pt-Ru catalyst layers for the anode.

High-throughput technology for novel SO2 oxidation catalysts

International Nuclear Information System (INIS)

Loskyll, Jonas; Stoewe, Klaus; Maier, Wilhelm F

2011-01-01

We review the state of the art and explain the need for better SO 2 oxidation catalysts for the production of sulfuric acid. A high-throughput technology has been developed for the study of potential catalysts in the oxidation of SO 2 to SO 3 . High-throughput methods are reviewed and the problems encountered with their adaptation to the corrosive conditions of SO 2 oxidation are described. We show that while emissivity-corrected infrared thermography (ecIRT) can be used for primary screening, it is prone to errors because of the large variations in the emissivity of the catalyst surface. UV-visible (UV-Vis) spectrometry was selected instead as a reliable analysis method of monitoring the SO 2 conversion. Installing plain sugar absorbents at reactor outlets proved valuable for the detection and quantitative removal of SO 3 from the product gas before the UV-Vis analysis. We also overview some elements used for prescreening and those remaining after the screening of the first catalyst generations. (topical review)

High Throughput In Situ XAFS Screening of Catalysts

International Nuclear Information System (INIS)

Tsapatsaris, Nikolaos; Beesley, Angela M.; Weiher, Norbert; Tatton, Helen; Schroeder, Sven L. M.; Dent, Andy J.; Mosselmans, Frederick J. W.; Tromp, Moniek; Russu, Sergio; Evans, John; Harvey, Ian; Hayama, Shu

2007-01-01

We outline and demonstrate the feasibility of high-throughput (HT) in situ XAFS for synchrotron radiation studies. An XAS data acquisition and control system for the analysis of dynamic materials libraries under control of temperature and gaseous environments has been developed. The system is compatible with the 96-well industry standard and coupled to multi-stream quadrupole mass spectrometry (QMS) analysis of reactor effluents. An automated analytical workflow generates data quickly compared to traditional individual spectrum acquisition and analyses them in quasi-real time using an HT data analysis tool based on IFFEFIT. The system was used for the automated characterization of a library of 91 catalyst precursors containing ternary combinations of Cu, Pt, and Au on γ-Al2O3, and for the in situ characterization of Au catalysts supported on Al2O3 and TiO2

Low temperature incineration of mixed wastes using bulk metal oxide catalysts

International Nuclear Information System (INIS)

Gordon, M.J.; Gaur, S.; Kelkar, S.; Baldwin, R.M.

1996-01-01

Volume reduction of low-level mixed wastes from former nuclear weapons facilities is a significant environmental problem. Processing of these materials presents unique scientific and engineering problems due to the presence of minute quantities of radionuclides which must be contained and concentrated for later safe disposal. Low-temperature catalytic incineration is one option that has been utilized at the Rocky Flats facility for this purpose. This paper presents results of research regarding evaluation of bulk metal oxides as catalysts for low-temperature incineration of carbonaceous residues which are typical by-products of fluidized bed combustion of mixed wastes under oxygen-lean conditions. A series of 14 metal oxides were screened in a thermogravimetric analyzer, using on-line mass spectrometry for speciation of reaction product gases. Catalyst evaluation criteria focused on the thermal-redox activity of the metals using both carbon black and PVC char as surrogate waste materials. Results indicated that metal oxides which were P-type semiconductor materials were suitable as catalysts for this application. Oxides of cobalt, molybdenum, vanadium, and manganese were found to be particularly stable and active catalysts under conditions specific to this process (T<650C, low oxygen partial pressures). Bench-scale evaluation of these metal oxides with respect to stability to chlorine (HCl) attack was carried out at 550C using a TG/MS system. Cobalt oxide was found to be resistant to metal loss in a HCl/He gaseous environment while metal loss from Mo, Mn, and V-based catalysts was moderate to severe. XRD and SEM/EDX analysis of spent Co catalysts indicated the formation of non-stoichiometric cobalt chlorides. Regeneration of chlorinated cobalt was found to successfully restore the low-temperature combustion activity to that of the fresh metal oxide

An efficient route to selective bio-oxidation catalysts: an iterative approach comprising modeling, diversification, and screening, based on CYP102A1.

Science.gov (United States)

Seifert, Alexander; Antonovici, Mihaela; Hauer, Bernhard; Pleiss, Jürgen

2011-06-14

Perillyl alcohol is the terminal hydroxylation product of the cheap and readily available terpene, limonene. It has high potential as an anti-tumor substance, but is of limited availability. In principle, cytochrome P450 monooxygenases, such as the self-sufficient CYP102A1, are promising catalysts for the oxidation of limonene or other inert hydrocarbons. The wild-type enzyme converts (4R)-limonene to four different oxidation products; however, terminal hydroxylation at the allylic C7 is not observed. Here we describe a generic strategy to engineer this widely used enzyme to hydroxylate exclusively the exposed, but chemically less reactive, primary C7 in the presence of other reactive positions. The approach presented here turns CYP102A1 into a highly selective catalyst with a shifted product spectra by successive rounds of modeling, the design of small focused libraries, and screening. In the first round a minimal CYP102A1 mutant library was rationally designed. It contained variants with improved or strongly shifted regio-, stereo- and chemoselectivity, compared to wild-type. From this library the variant with the highest perillyl alcohol ratio was fine-tuned by two additional rounds of molecular modeling, diversification, and screening. In total only 29 variants needed to be screened to identify the triple mutant A264V/A238V/L437F that converts (4R)-limonene to perillyl alcohol with a selectivity of 97 %. Focusing mutagenesis on a small number of relevant positions identified by computational approaches is the key for efficient screening for enzyme selectivity. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrogen production from bio-fuels using precious metal catalysts

Science.gov (United States)

Pasel, Joachim; Wohlrab, Sebastian; Rotov, Mikhail; Löhken, Katrin; Peters, Ralf; Stolten, Detlef

2017-11-01

Fuel cell systems with integrated autothermal reforming unit require active and robust catalysts for H2 production. Thus, an experimental screening of catalysts for autothermal reforming of commercial biodiesel fuel was performed. Catalysts consisted of a monolithic cordierite substrate, an oxide support (γ-Al2O3) and Pt, Ru, Ni, PtRh and PtRu as active phase. Experiments were run by widely varying the O2/C and H2O/C molar ratios at different gas hourly space velocities. Fresh and aged catalysts were characterized by temperature programmed methods and thermogravimetry to find correlations with catalytic activity and stability.

In silico search for novel methane steam reforming catalysts

International Nuclear Information System (INIS)

Xu, Yue; Lausche, Adam C; Khan, Tuhin S; Abild-Pedersen, Frank; Studt, Felix; Nørskov, Jens K; Bligaard, Thomas; Wang, Shengguang

2013-01-01

This paper demonstrates a method for screening transition metal and metal alloy catalysts based on their predicted rates and stabilities for a given catalytic reaction. This method involves combining reaction and activation energies (available to the public via a web-based application ‘CatApp’) with a microkinetic modeling technique to predict the rates and selectivities of a prospective material. This paper illustrates this screening technique using the steam reforming of methane to carbon monoxide and hydrogen as a test reaction. While catalysts are already commercially available for this process, the method demonstrated in this paper is very general and could be applied to a wide range of catalytic reactions. Following the steps outlined herein, such an analysis could potentially enable researchers to understand reaction mechanisms on a fundamental level and, on this basis, develop leads for new metal alloy catalysts. (paper)

Hanford ferrocyanide waste chemistry and reactivity preliminary catalyst and initiator screening studies

International Nuclear Information System (INIS)

Scheele, R.D.; Bryan, S.A.; Johnston, J.W.; Tingey, J.M.; Burger, L.L.; Hallen, R.T.

1992-05-01

During the 1950s, ferrocyanide was used to scavenge radiocesium from aqueous nitrate-containing Hanford wastes. During the production of defense materials and while these wastes were stored in high-level waste tanks at the Hanford Site, some of these wastes were likely mixed with other waste constituents and materials. Recently, Pacific Northwest Laboratory (PNL) was commissioned by Westinghouse Hanford Company (WHC) to investigate the chemical reactivity of these ferrocyanide-bearing wastes. Because of known or potential thermal reactivity hazards associated with ferrocyanide- and nitrate-bearing wastes, and because of the potential for different materials to act as catalysts or initiators of the reactions about which there is concern, we at PNL have begun investigating the effects of the other potential waste constituents. This report presents the results of a preliminary screening study to identify classes of materials that might be in the Hanford high-level waste tanks and that could accelerate or reduce the starting temperature of the reaction(s) of concern. We plan to use the resulted of this study to determine which materials or class of materials merit additional research

Studies on recycling and utilization of spent catalysts. Preparation of active hydrodemetallization catalyst compositions from spent residue hydroprocessing catalysts

Energy Technology Data Exchange (ETDEWEB)

Marafi, Meena; Stanislaus, Antony [Petroleum Refining Department, Petroleum Research and Studies Center, Kuwait Institute for Scientific Research, P.O. Box 24885, Safat (Kuwait)

2007-02-15

Spent catalysts form a major source of solid wastes in the petroleum refining industries. Due to environmental concerns, increasing emphasis has been placed on the development of recycling processes for the waste catalyst materials as much as possible. In the present study the potential reuse of spent catalysts in the preparation of active new catalysts for residual oil hydrotreating was examined. A series of catalysts were prepared by mixing and extruding spent residue hydroprocessing catalysts that contained C, V, Mo, Ni and Al{sub 2}O{sub 3} with boehmite in different proportions. All prepared catalysts were characterized by chemical analysis and by surface area, pore volume, pore size and crushing strength measurements. The hydrodesulfurization (HDS) and hydrodemetallization (HDM) activities of the catalysts were evaluated by testing in a high pressure fixed-bed microreactor unit using Kuwait atmospheric residue as feed. A commercial HDM catalyst was also tested under similar operating conditions and their HDS and HDM activities were compared with that of the prepared catalysts. The results revealed that catalyst prepared with addition of up to 40 wt% spent catalyst to boehmite had fairly high surface area and pore volume together with large pores. The catalyst prepared by mixing and extruding about 40 wt% spent catalyst with boehmite was relatively more active for promoting HDM and HDS reactions than a reference commercial HDM catalyst. The formation of some kind of new active sites from the metals (V, Mo and Ni) present in the spent catalyst is suggested to be responsible for the high HDM activity of the prepared catalyst. (author)

Hydrogen production from bio-fuels using precious metal catalysts

Directory of Open Access Journals (Sweden)

Pasel Joachim

2017-01-01

Full Text Available Fuel cell systems with integrated autothermal reforming unit require active and robust catalysts for H2 production. Thus, an experimental screening of catalysts for autothermal reforming of commercial biodiesel fuel was performed. Catalysts consisted of a monolithic cordierite substrate, an oxide support (γ-Al2O3 and Pt, Ru, Ni, PtRh and PtRu as active phase. Experiments were run by widely varying the O2/C and H2O/C molar ratios at different gas hourly space velocities. Fresh and aged catalysts were characterized by temperature programmed methods and thermogravimetry to find correlations with catalytic activity and stability.

Optimization of Rhodium-Based Catalysts for Mixed Alcohol Synthesis – 2012 Progress Report

Energy Technology Data Exchange (ETDEWEB)

Gerber, Mark A.; Gray, Michel J.; Albrecht, Karl O.; Thompson, Becky L.

2012-11-01

Pacific Northwest National Laboratory has been conducting research to investigate the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). In recent years, this research has primarily involved the further development of catalysts containing rhodium and manganese based on the results of earlier catalyst screening tests. Testing continued in FY 2012 to further improve the Ir-promoted RhMn catalysts on both silica and carbon supports for producing mixed oxygenates from synthesis gas. This testing re-examined selected alternative silica and carbon supports to follow up on some uncertainties in the results with previous test results. Additional tests were conducted to further optimize the total and relative concentrations of Rh, Mn, and Ir, and to examine selected promoters and promoter combinations based on earlier results. To establish optimum operating conditions, the effects of the process pressure and the feed gas composition also were evaluated.

CATALYTIC STEAM REFORMING OF CHLOROCARBONS: CATALYST COMPARISONS. (R826694C633)

Science.gov (United States)

Catalyst candidates for steam reforming chlorocarbons have been screened for activity using methyl chloride as a model reactant. At 500°C, a H2O/C ratio of about 10 and a GHSV of 254 000 h-1, catalysts comprising 0.5% loading of the metals ...

CATALYTIC STEAM REFORMING OF CHLOROCARBONS: CATALYST COMPARISONS. (R822721C633)

Science.gov (United States)

Catalyst candidates for steam reforming chlorocarbons have been screened for activity using methyl chloride as a model reactant. At 500°C, a H2O/C ratio of about 10 and a GHSV of 254 000 h-1, catalysts comprising 0.5% loading of the metals o...

New proposition on performance evaluation of hydrophobic Pt catalyst packed in trickle bed

International Nuclear Information System (INIS)

Shimizu, Masami; Kitamoto, Asashi; Takashima, Yoichi.

1983-01-01

On the evaluation of the performance of the hydrophobic Pt catalyst packed in the trickle-bed test column, the conventionally defined (Ksub(y)a) and the newly defined (Ksub(f))sub (G) are compared with each other as a measure of the overall D-transfer coefficient. The value of (Ksub(y)a) varies in a wide range in accordance with the length of the test column. On the other hand (Ksub(f))sub (G sub (l = L)) has a finite value in the test column longer than about 0.5 m. By considering the values of ksub(g) and ksub(l) which are the constituents of (Ksub(f))sub (G), it is possible to improve the hydrophobic Pt catalyst trickle bed and to design the H 2 /H 2 O-isotopic exchange trickle-bed column packed with this catalyst. (author)

Non-PGM cell catalysts

Energy Technology Data Exchange (ETDEWEB)

Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Elvington, M. [Savannah River Consulting, Aiken, SC (United States); Ganesan, P. [Savannah River Consulting, Aiken, SC (United States)

2017-09-27

A unique approach has been developed to probe the non-PGM catalyst active site for the Oxygen Reduction Reaction (ORR) for PEMFCs. Iron based functionalities have been engineered into a variety of catalysts to evaluate their impact on activity for the ORR. A series of high surface area catalysts were synthesized and the impact of the chemical structure on the electrochemical and electrocatalytic properties was investigated. Elemental and surface analyses of the prepared catalysts reveal the incorporation of iron in a targeted and controlled manner. A high surface area framework catalyst was prepared that shows exceptional activity, comparable to state-of-the-art materials. The results of this research project provided critical seed data for the newly awarded ElectroCat project, which focuses on rationally designed framework catalysts for the oxygen reduction reaction.

Finding furfural hydrogenation catalysts via predictive modelling

NARCIS (Netherlands)

Strassberger, Z.; Mooijman, M.; Ruijter, E.; Alberts, A.H.; Maldonado, A.G.; Orru, R.V.A.; Rothenberg, G.

2010-01-01

We combine multicomponent reactions, catalytic performance studies and predictive modelling to find transfer hydrogenation catalysts. An initial set of 18 ruthenium-carbene complexes were synthesized and screened in the transfer hydrogenation of furfural to furfurol with isopropyl alcohol complexes

Evaluation of functionalized silica's for the adsorptive recovery of homogeneous catalysts through interaction with the metal centre

NARCIS (Netherlands)

Djekic, T.; Ham, van der A.G.J.; Haan, de A.B.

2007-01-01

The goal of this paper is the evaluation of functionalized silica's for the recovery of homogeneous catalysts by adsorption via its metal centre. As model catalysts, we selected bis(triphenylphosphine)cobalt(II)dichloride (CoCl2(PPh3)2), bis(triphenylphosphine)palladium(II)dichloride (PdCl2(PPh3)2)

Finding Furfural Hydrogenation Catalysts via Predictive Modelling.

Science.gov (United States)

Strassberger, Zea; Mooijman, Maurice; Ruijter, Eelco; Alberts, Albert H; Maldonado, Ana G; Orru, Romano V A; Rothenberg, Gadi

2010-09-10

We combine multicomponent reactions, catalytic performance studies and predictive modelling to find transfer hydrogenation catalysts. An initial set of 18 ruthenium-carbene complexes were synthesized and screened in the transfer hydrogenation of furfural to furfurol with isopropyl alcohol complexes gave varied yields, from 62% up to >99.9%, with no obvious structure/activity correlations. Control experiments proved that the carbene ligand remains coordinated to the ruthenium centre throughout the reaction. Deuterium-labelling studies showed a secondary isotope effect (k(H):k(D)=1.5). Further mechanistic studies showed that this transfer hydrogenation follows the so-called monohydride pathway. Using these data, we built a predictive model for 13 of the catalysts, based on 2D and 3D molecular descriptors. We tested and validated the model using the remaining five catalysts (cross-validation, R(2)=0.913). Then, with this model, the conversion and selectivity were predicted for four completely new ruthenium-carbene complexes. These four catalysts were then synthesized and tested. The results were within 3% of the model's predictions, demonstrating the validity and value of predictive modelling in catalyst optimization.

Pt Catalyst Supported within TiO2 Mesoporous Films for Oxygen Reduction Reaction

International Nuclear Information System (INIS)

Huang, Dekang; Zhang, Bingyan; Bai, Jie; Zhang, Yibo; Wittstock, Gunther; Wang, Mingkui; Shen, Yan

2014-01-01

In this study, dispersed Pt nanoparticles into mesoporous TiO 2 thin films are fabricated by a facile electrochemical deposition method as electro-catalysts for oxygen reduction reaction. The mesoporous TiO 2 thin films coated on the fluorine-doped tin oxide glass by screen printing allow a facile transport of reactants and products. The structural properties of the resulted Pt/TiO 2 electrode are evaluated by field emission scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. Cyclic voltammetry measurements are performed to study the electrochemical properties of the Pt/TiO 2 electrode. Further study demonstrates the stability of the Pt catalyst supported within TiO 2 mesoporous films for the oxygen reduction reaction

Evaluation of mechanical properties in metal wire mesh supported selective catalytic reduction (SCR) catalyst structures

Science.gov (United States)

Rajath, S.; Siddaraju, C.; Nandakishora, Y.; Roy, Sukumar

2018-04-01

The objective of this research is to evaluate certain specific mechanical properties of certain stainless steel wire mesh supported Selective catalytic reduction catalysts structures wherein the physical properties of the metal wire mesh and also its surface treatments played vital role thereby influencing the mechanical properties. As the adhesion between the stainless steel wire mesh and the catalyst material determines the bond strength and the erosion resistance of catalyst structures, surface modifications of the metal- wire mesh structure in order to facilitate the interface bonding is therefore very important to realize enhanced level of mechanical properties. One way to enhance such adhesion properties, the stainless steel wire mesh is treated with the various acids, i.e., chromic acid, phosphoric acid including certain mineral acids and combination of all those in various molar ratios that could generate surface active groups on metal surface that promotes good interface structure between the metal- wire mesh and metal oxide-based catalyst material and then the stainless steel wire mesh is dipped in the glass powder slurry containing some amount of organic binder. As a result of which the said catalyst material adheres to the metal-wire mesh surface more effectively that improves the erosion profile of supported catalysts structure including bond strength.

Evaluation of an olefin metathesis pre-catalyst with a bulky and electron-rich N-heterocyclic carbene

KAUST Repository

Manzini, Simone

2015-03-01

The commercially-available metathesis pre-catalyst M23 has been evaluated alongside new complex [RuCl2((3-phenyl)indenylidene)(PPh3)(SIPrOMe)] (1), which bears a para-methoxy-substituted N-heterocyclic carbene ligand. Several model metathesis reactions could be conducted using only parts-per-million levels of ruthenium catalyst. The effects of the different NHC ligands on reactivity have been explored.

Evaluation of an olefin metathesis pre-catalyst with a bulky and electron-rich N-heterocyclic carbene

KAUST Repository

Manzini, Simone; Urbina Blanco, Cé sar A.; Nelson, David J.; Poater, Albert; Lebl, Tomas; Meiries, Sé bastien; Slawin, Alexandra M.Z.; Falivene, Laura; Cavallo, Luigi; Nolan, Steven P.

2015-01-01

The commercially-available metathesis pre-catalyst M23 has been evaluated alongside new complex [RuCl2((3-phenyl)indenylidene)(PPh3)(SIPrOMe)] (1), which bears a para-methoxy-substituted N-heterocyclic carbene ligand. Several model metathesis reactions could be conducted using only parts-per-million levels of ruthenium catalyst. The effects of the different NHC ligands on reactivity have been explored.

Combinatorial computational chemistry approach to the design of metal catalysts for deNOx

International Nuclear Information System (INIS)

Endou, Akira; Jung, Changho; Kusagaya, Tomonori; Kubo, Momoji; Selvam, Parasuraman; Miyamoto, Akira

2004-01-01

Combinatorial chemistry is an efficient technique for the synthesis and screening of a large number of compounds. Recently, we introduced the combinatorial approach to computational chemistry for catalyst design and proposed a new method called ''combinatorial computational chemistry''. In the present study, we have applied this combinatorial computational chemistry approach to the design of precious metal catalysts for deNO x . As the first step of the screening of the metal catalysts, we studied Rh, Pd, Ag, Ir, Pt, and Au clusters regarding the adsorption properties towards NO molecule. It was demonstrated that the energetically most stable adsorption state of NO on Ir model cluster, which was irrespective of both the shape and number of atoms including the model clusters

[Comparing audiological evaluation and screening: a study on presbycusis].

Science.gov (United States)

Samelli, Alessandra Giannella; Negretti, Camila Aparecida; Ueda, Kerli Saori; Moreira, Renata Rodrigues; Schochat, Eliane

2011-01-01

Given the high prevalence of presbycusis and the damage it brings about, a screening test can be useful in the identification of hearing loss in primary care. To estimate the prevalence of hearing loss in a representative sample of elderly people living at Butantan using an audiological screening method (questionnaire) and a basic audiological evaluation; to compare the results of the two kinds of evaluations, checking the validity of this tool for hearing loss screening. Cross sectional descriptive study. 200 individuals (above 60 years old, both genders) were randomly selected to undergo audiological screening (questionnaire). Another randomly selected group encompassed 100 individuals who were submitted to a set of audiological tests. Then, we compared the results from the two methods. There were no statistically significant associations between the questionnaire and the degree of hearing loss of the patients. The prevalence of hearing loss in our sample was of 56% in the screening and of 95% when checked by the audiological evaluation. Therefore, screening was not proven valid to assess hearing when compared to audiological evaluation.

Characterization and evaluation of Pt-Ru catalyst supported on multi-walled carbon nanotubes by electrochemical impedance

Energy Technology Data Exchange (ETDEWEB)

Ocampo, A.L.; Miranda-Hernandez, M.; Sebastian, P.J. [Centro de Investigacion en Energia-UNAM, Temixco, 62580 Morelos (Mexico); Morgado, J.; Montoya, J.A. [IMP, Eje Central Lazaro Cardenas 152, 07730 D.F. Mexico (Mexico)

2006-10-06

In this work the authors present the results of a systematic characterization and evaluation of the carbon nanotube supported Pt-Ru (Pt-Ru/CNT) for its use as methanol oxidation catalyst. Its activity was compared with that of Pt and Pt-Ru catalysts supported on Vulcan and synthesized from carbonyl precursors, and another commercial Pt-Ru catalyst. The cyclic voltammetry, CO stripping and electrochemical impedance techniques were employed to determine the electrocatalytic activity of the catalysts. The electrochemical studies were performed in 0.5M H{sub 2}SO{sub 4} containing different concentrations of methanol (0.05-1M). The results showed a noticeable influence of the catalyst support (CNT) on the performance of the catalyst for CO oxidation. The electrochemical impedance studies allowed us to separate the different steps in the methanol oxidation reaction and to control these steps or reactions by varying the applied potential and the methanol concentration. At low methanol concentration and potentials the de-hydrogenation of methanol predominated. But, at high potential and methanol concentrations, the CO oxidation predominated. These results allowed us to clearly describe at what potential and concentration ranges the bi-functional effect of Ru becomes evident. Our results indicated that the CO oxidation occurs both on Pt and Ru. Compared to other catalysts, Pt-Ru supported on carbon nanotubes showed superior catalytic activity for CO and methanol oxidation. (author)

EFFECT OF VANADIUM ON THE DEACTIVATION OF FCC CATALYSTS

Directory of Open Access Journals (Sweden)

Roncolatto R.E

1998-01-01

Full Text Available This work provides concrete evidence that vanadium causes the destruction of the zeolite in the FCC catalysts by a mechanism of acid attack or solid-solid transformation, as well as additional dealumination of the zeolite framework in the presence of steam and at high temperature. While these effects resulted in the reduction in crystallinity (zeolite Y content, specific area and unit cell size of the Y zeolite as the amount of vanadium in the catalysts increased, the reduction in activity was the most pronounced. The differences in these behaviors were interpreted and the model can be used for better catalyst formulation or screening.

Finding Furfural Hydrogenation Catalysts via Predictive Modelling

Science.gov (United States)

Strassberger, Zea; Mooijman, Maurice; Ruijter, Eelco; Alberts, Albert H; Maldonado, Ana G; Orru, Romano V A; Rothenberg, Gadi

2010-01-01

Abstract We combine multicomponent reactions, catalytic performance studies and predictive modelling to find transfer hydrogenation catalysts. An initial set of 18 ruthenium-carbene complexes were synthesized and screened in the transfer hydrogenation of furfural to furfurol with isopropyl alcohol complexes gave varied yields, from 62% up to >99.9%, with no obvious structure/activity correlations. Control experiments proved that the carbene ligand remains coordinated to the ruthenium centre throughout the reaction. Deuterium-labelling studies showed a secondary isotope effect (kH:kD=1.5). Further mechanistic studies showed that this transfer hydrogenation follows the so-called monohydride pathway. Using these data, we built a predictive model for 13 of the catalysts, based on 2D and 3D molecular descriptors. We tested and validated the model using the remaining five catalysts (cross-validation, R2=0.913). Then, with this model, the conversion and selectivity were predicted for four completely new ruthenium-carbene complexes. These four catalysts were then synthesized and tested. The results were within 3% of the model’s predictions, demonstrating the validity and value of predictive modelling in catalyst optimization. PMID:23193388

Hydrodenitrogenation of heavy oil--1. Survey of hydrodenitrogenation catalysts

Energy Technology Data Exchange (ETDEWEB)

Nakamura, M.; Ono, T.; Togari, O.

1979-11-01

Forty catalysts consisting of binary oxides of silica/alumina, zirconium dioxide, titanium dioxide, or magnesium oxide or alumina/boron oxide, titanium dioxide, zirconium dioxide, or phosphorus pentoxide in various proportions, or of alumina alone, were screened for their activity for hydrodenitrogenation (kn) and hydrodesulfurization (ks) of a Gach Saran vacuum gas oil containing 0.16Vertical Bar3< nitrogen and 2.0Vertical Bar3< sulfur. The activities were correlated with the acid amount and acid strength of the catalysts as measured by temperature-programed desorption of ammonia. The mixed oxides of silica had low kn and low ks, and the kn was proportional to the acidity. The unmixed alumina catalysts showed low kn and high ks and no obvious relationship between activity and acidity. The binary alumina catalysts showed high kn and high ks and no obvious correlation between acidity and activity. Generally, catalysts with high acid strength had the lowest kn, especially the unmixed alumina.

Enhanced performance of a novel anodic PdAu/VGCNF catalyst for electro-oxidation in a glycerol fuel cell.

Science.gov (United States)

Yahya, N; Kamarudin, S K; Karim, N A; Masdar, M S; Loh, K S

2017-11-25

This study presents a novel anodic PdAu/VGCNF catalyst for electro-oxidation in a glycerol fuel cell. The reaction conditions are critical issues affecting the glycerol electro-oxidation performance. This study presents the effects of catalyst loading, temperature, and electrolyte concentration. The glycerol oxidation performance of the PdAu/VGCNF catalyst on the anode side is tested via cyclic voltammetry with a 3 mm 2 active area. The morphology and physical properties of the catalyst are examined using X-ray diffraction (XRD), field emission scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. Then, optimization is carried out using the response surface method with central composite experimental design. The current density is experimentally obtained as a response variable from a set of experimental laboratory tests. The catalyst loading, temperature, and NaOH concentration are taken as independent parameters, which were evaluated previously in the screening experiments. The highest current density of 158.34 mAcm -2 is obtained under the optimal conditions of 3.0 M NaOH concentration, 60 °C temperature and 12 wt.% catalyst loading. These results prove that PdAu-VGCNF is a potential anodic catalyst for glycerol fuel cells.

Bifunctional anode catalysts for direct methanol fuel cells

DEFF Research Database (Denmark)

Rossmeisl, Jan; Ferrin, Peter; Tritsaris, Georgios

2012-01-01

Using the binding energy of OH* and CO* on close-packed surfaces as reactivity descriptors, we screen bulk and surface alloy catalysts for methanol electro-oxidation activity. Using these two descriptors, we illustrate that a good methanol electro-oxidation catalyst must have three key properties......: (1) the ability to activate methanol, (2) the ability to activate water, and (3) the ability to react off surface intermediates (such as CO* and OH*). Based on this analysis, an alloy catalyst made up of Cu and Pt should have a synergistic effect facilitating the activity towards methanol electro-oxidation....... Adding Cu to a Pt(111) surface increases the methanol oxidation current by more than a factor of three, supporting our theoretical predictions for improved electrocatalysts....

Screening Risk Evaluation methodology

International Nuclear Information System (INIS)

Hopper, K.M.

1994-01-01

The Screening Risk Evaluation (SRE) Guidance document is a set of guidelines provided for the uniform implementation of SREs performed on D ampersand D facilities. These guidelines are designed specifically for the completion of the second (semi-quantitative screening) phase of the D ampersand D Risk-Based Process. The SRE Guidance produces screening risk scores reflecting levels of risk through the use of risk ranking indices. Five types of possible risk are calculated from the SRE: current releases, worker exposures, future releases, physical hazards, and criticality. The Current Release Index (CRI) calculates the risk to human health and the environment from ongoing or probable releases within a one year time period. The Worker Exposure Index (WEI) calculates the risk to workers, occupants, and visitors in D ampersand D facilities of contaminant exposure. The Future Release Index (FRI) calculates the risk of future releases of contaminants, after one year, to human health and the environment. The Physical Hazards Index (PHI) calculates the risk-to human health due to factors other than that of contaminants. The index of Criticality is approached as a modifying factor to the entire SRE, due to the fact that criticality issues are strictly regulated under DOE. Screening risk results will be tabulated in matrix form and Total Risk will be calculated (weighted equation) to produce a score on which to base early action recommendations. Other recommendations from the screening risk scores will be made based either on individual index scores or from reweighted Total Risk calculations. All recommendations based on the SRE will be made based on a combination of screening risk scores, decision drivers, and other considerations, determined on a project by project basis. The SRE is the first and most important step in the overall D ampersand D project level decision making process

Mono-, bi-, and tri-metallic Ni-based catalysts for the catalytic hydrotreatment of pyrolysis liquids

NARCIS (Netherlands)

Yin, Wang; Venderbosch, Robbie H.; He, Songbo; Bykova, Maria V.; Khromova, Sofia A.; Yakovlev, Vadim A.; Heeres, Hero J.

Catalytic hydrotreatment is a promising technology to convert pyrolysis liquids into intermediates with improved properties. Here, we report a catalyst screening study on the catalytic hydrotreatment of pyrolysis liquids using bi- and tri-metallic nickel-based catalysts in a batch autoclave (initial

High-Activity Dealloyed Catalysts

Energy Technology Data Exchange (ETDEWEB)

Kongkanand, Anusorn [General Motors LLC, Pontiac, MI (United States)

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.

Systematic review of model-based cervical screening evaluations.

Science.gov (United States)

Mendes, Diana; Bains, Iren; Vanni, Tazio; Jit, Mark

2015-05-01

Optimising population-based cervical screening policies is becoming more complex due to the expanding range of screening technologies available and the interplay with vaccine-induced changes in epidemiology. Mathematical models are increasingly being applied to assess the impact of cervical cancer screening strategies. We systematically reviewed MEDLINE®, Embase, Web of Science®, EconLit, Health Economic Evaluation Database, and The Cochrane Library databases in order to identify the mathematical models of human papillomavirus (HPV) infection and cervical cancer progression used to assess the effectiveness and/or cost-effectiveness of cervical cancer screening strategies. Key model features and conclusions relevant to decision-making were extracted. We found 153 articles meeting our eligibility criteria published up to May 2013. Most studies (72/153) evaluated the introduction of a new screening technology, with particular focus on the comparison of HPV DNA testing and cytology (n = 58). Twenty-eight in forty of these analyses supported HPV DNA primary screening implementation. A few studies analysed more recent technologies - rapid HPV DNA testing (n = 3), HPV DNA self-sampling (n = 4), and genotyping (n = 1) - and were also supportive of their introduction. However, no study was found on emerging molecular markers and their potential utility in future screening programmes. Most evaluations (113/153) were based on models simulating aggregate groups of women at risk of cervical cancer over time without accounting for HPV infection transmission. Calibration to country-specific outcome data is becoming more common, but has not yet become standard practice. Models of cervical screening are increasingly used, and allow extrapolation of trial data to project the population-level health and economic impact of different screening policy. However, post-vaccination analyses have rarely incorporated transmission dynamics. Model calibration to country

Process evaluation of health fairs promoting cancer screenings.

Science.gov (United States)

Escoffery, Cam; Liang, Shuting; Rodgers, Kirsten; Haardoerfer, Regine; Hennessy, Grace; Gilbertson, Kendra; Heredia, Natalia I; Gatus, Leticia A; Fernandez, Maria E

2017-12-18

Low income and uninsured individuals often have lower adherence to cancer screening for breast, cervical and colorectal cancer. Health fairs are a common community outreach strategy used to provide cancer-related health education and services. This study was a process evaluation of seven health fairs focused on cancer screening across the U.S. We conducted key-informant interviews with the fair coordinator and conducted baseline and follow-up surveys with fair participants to describe characteristics of participants as well as their experiences. We collected baseline data with participants at the health fairs and telephone follow-up surveys 6 months following the fair. Attendance across the seven health fairs ranged from 41 to 212 participants. Most fairs provided group or individual education, print materials and cancer screening during the event. Overall, participants rated health fairs as very good and participants reported that the staff was knowledgeable and that they liked the materials distributed. After the fairs, about 60% of participants, who were reached at follow-up, had read the materials provided and had conversations with others about cancer screening, and 41% talked to their doctors about screening. Based on findings from evaluation including participant data and coordinator interviews, we describe 6 areas in planning for health fairs that may increase their effectiveness. These include: 1) use of a theoretical framework for health promotion to guide educational content and activities provided, 2) considering the community characteristics, 3) choosing a relevant setting, 4) promotion of the event, 5) considerations of the types of services to deliver, and 6) evaluation of the health fair. The events reported varied in reach and the participants represented diverse races and lower income populations overall. Most health fairs offered education, print materials and onsite cancer screening. Participants reported general satisfaction with these events

Evaluation of Pt-Ru-Ni and Pt-Sn-Ni catalysts as anodes in direct ethanol fuel cells

Energy Technology Data Exchange (ETDEWEB)

Ribadeneira, Esteban; Hoyos, Bibian A. [Escuela de Procesos y Energia, Facultad de Minas, Universidad Nacional de Colombia, Medellin (Colombia)

2008-05-15

In this study, the electrooxidation of ethanol on carbon supported Pt-Ru-Ni and Pt-Sn-Ni catalysts is electrochemically studied through cyclic voltammetry at 50 C in direct ethanol fuel cells. All electrocatalysts are prepared using the ethylene glycol-reduction process and are chemically characterized by energy-dispersive X-ray analysis (EDX). For fuel cell evaluation, electrodes are prepared by the transfer-decal method. Nickel addition to the anode improves DEFC performance. When Pt{sub 75}Ru{sub 15}Ni{sub 10}/C is used as an anode catalyst, the current density obtained in the fuel cell is greater than that of all other investigated catalysts. Tri-metallic catalytic mixtures have a higher performance relative to bi-metallic catalysts. These results are in agreement with CV results that display greater activity for PtRuNi at higher potentials. (author)

Evaluation as a catalyst in ferrispinel NiFe_2O_4 esterification and transesterification

International Nuclear Information System (INIS)

Pereira, Kleberson Ricardo de Oliveira; Dantas, Joelda; Costa, Ana Cristina Figueiredo de Melo; Silva, Adriano Sant'Ana; Kiminami, Ruth Herta Goldschmidt Aliaga

2014-01-01

The advancement of nanoscience and nanotechnology, magnetic nanoparticles ferrispinels type, have found numerous applications in biochemistry, molecular biology, biomedicine, diagnosis and heterogeneous catalysis for biodiesel production. Therefore, we propose to synthesize ferrispinel NiFe_2O_4 and evaluate its performance as a catalyst for esterification and transesterification of the methyl soybean oil. The sample was obtained through combustion reaction with production of 10 g / batch and characterized by XRD, SEM and BET. The catalytic reaction was conducted in high-pressure reactor at 180 °C for 1 hour, with a molar ratio of oil:ethanol 1:12 with 2% catalyst. The results showed the formation of ferrispinel phase, morphology composed of aggregates in the form of irregular blocks formed by pre sintered particles and low interparticle porosity. As a catalyst, the conversion values presented ferrispinel 52% and 4% in the esterification and transesterification, respectively, indicating that promising material for use in biodiesel production. (author)

Catalyst Stability Benchmarking for the Oxygen Evolution Reaction: The Importance of Backing Electrode Material and Dissolution in Accelerated Aging Studies.

Science.gov (United States)

Geiger, Simon; Kasian, Olga; Mingers, Andrea M; Nicley, Shannon S; Haenen, Ken; Mayrhofer, Karl J J; Cherevko, Serhiy

2017-09-18

In searching for alternative oxygen evolution reaction (OER) catalysts for acidic water splitting, fast screening of the material intrinsic activity and stability in half-cell tests is of vital importance. The screening process significantly accelerates the discovery of new promising materials without the need of time-consuming real-cell analysis. In commonly employed tests, a conclusion on the catalyst stability is drawn solely on the basis of electrochemical data, for example, by evaluating potential-versus-time profiles. Herein important limitations of such approaches, which are related to the degradation of the backing electrode material, are demonstrated. State-of-the-art Ir-black powder is investigated for OER activity and for dissolution as a function of the backing electrode material. Even at very short time intervals materials like glassy carbon passivate, increasing the contact resistance and concealing the degradation phenomena of the electrocatalyst itself. Alternative backing electrodes like gold and boron-doped diamond show better stability and are thus recommended for short accelerated aging investigations. Moreover, parallel quantification of dissolution products in the electrolyte is shown to be of great importance for comparing OER catalyst feasibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of functionalized silica¿s for the adsorptive recovery of homogenous catalysts through interaction with the metal centre

NARCIS (Netherlands)

Djekic, T.; van der Ham, Aloysius G.J.; de Haan, A.B.

2007-01-01

The goal of this paper is the evaluation of functionalized silica's for the recovery of homogeneous catalysts by adsorption via its metal centre. As model catalysts, we selected bis(triphenylphosphine)cobalt(II)dichloride (CoCl2(PPh3)2), bis(triphenylphosphine)palladium(II)dichloride (PdCl2(PPh3)2)

[Reasearch progress in health economic evaluation of colorectal cancer screening in China].

Science.gov (United States)

Huang, Huiyao; Shi, Jufang; Dai, Min

2015-08-01

Burden of colorectal cancer is rising in China. More attention and financial input have been paid to it by central government that colorectal cancer screening program has been carried out recently in many areas in China. Diversity of screening strategies and limited health resources render selecting the best strategy in a population-wide program a challenging task that economy was also required to be considered except safety and efficacy. To provide a reference for the subsequent further economic evaluation, here we reviewed the evidence available on the economic evaluation of colorectal cancer screening in China. Meanwhile, information related to screening strategies, participation and mid-term efficacy of screening, information and results on economic evaluation were extracted and summarized. Three of the four studies finally included evaluated strategies combining immunochemical fecel occult blood test (iFOBT) with high-risk factor questionnaire as initial screening, colonoscopy as diagnostic screening. There was a consensus regarding the efficacy and effectiveness of screening compared to no screening. Whereas the lack and poor comparability between studies, multi-perspective and multi-phase economic evaluation of colorectal cancer screening is needed, relying on current population-based screening program to conduct a comprehensive cost accounting.

Evaluation of photocatalytic activities of supported catalysts on NaX zeolite or activated charcoal

Energy Technology Data Exchange (ETDEWEB)

Brites-Nóbrega, Fernanda F. de [Chemical Engineering Department, Universidade Estadual de Maringá (UEM), Av. Colombo, 5790, CEP 87020-900 Maringá, PR (Brazil); Sanitary and Environmental Engineering Department, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Campus Pampulha, Belo Horizonte, MG (Brazil); Polo, Aldino N.B.; Benedetti, Angélica M. [Chemical Engineering Department, Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua da Faculdade, 645, CEP 85903-000 Toledo, PR (Brazil); Leão, Mônica M.D. [Sanitary and Environmental Engineering Department, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Campus Pampulha, Belo Horizonte, MG (Brazil); Slusarski-Santana, Veronice, E-mail: veronice.santana@unioeste.br [Chemical Engineering Department, Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua da Faculdade, 645, CEP 85903-000 Toledo, PR (Brazil); Fernandes-Machado, Nádia R.C. [Chemical Engineering Department, Universidade Estadual de Maringá (UEM), Av. Colombo, 5790, CEP 87020-900 Maringá, PR (Brazil)

2013-12-15

Highlights: • The synergic effect between ZnO and NaX was positive, which increased its activity. • The best results were obtained at pH 3 and 9 with ZnO/NaX and at pH 3 with Nb{sub 2}O{sub 5}/AC. • High degradation and considerable mineralization were attained with 10% ZnO/NaX. • ZnO and Nb{sub 2}O{sub 5} supported on NaX and AC are promising alternatives as photocatalysts. -- Abstract: This study aimed to evaluate the photocatalytic activity of ZnO and Nb{sub 2}O{sub 5} catalysts, both supported on NaX zeolite and activated charcoal (AC). The synergistic effect between oxide and support and the influence of solution pH (3, 7 and 9) on photocatalytic degradation of reactive blue 5G (C.I. 222) were analyzed. The catalysts Nb{sub 2}O{sub 5}/NaX, Nb{sub 2}O{sub 5}/AC and ZnO/NaX, ZnO/AC with 5 and 10% (wt%) were prepared by wet impregnation. The results showed that the catalysts exhibit quite different structural and textural properties. The synergic effect between ZnO and NaX support was higher than that with the activated charcoal, showing that these catalysts were more efficient. The most photoactive catalyst was 10% ZnO/NaX which showed 100% discoloration of the dye solution at pH 3, 7 and 9 after 0.5, 5 and 2 h of irradiation, respectively. The hydrolytic nature of zeolite favored the formation of surface hydroxyl radicals, which increased the activity of the photocatalyst. Thus, catalysts supported on NaX zeolite are promising for use in photocatalysis.

Toward computational screening in heterogeneous catalysis: Pareto-optimal methanation catalysts

DEFF Research Database (Denmark)

Andersson, Martin; Bligaard, Thomas; Kustov, Arkadii

2006-01-01

Finding the solids that are the best catalysts for a given reaction is a daunting task due to the large number of combinations and structures of multicomponent Surfaces. In addition, it is not only the reaction rate that needs to be optimized: the selectivity. durability. and cost Must also be ta...

A framework provided an outline toward the proper evaluation of potential screening strategies.

Science.gov (United States)

Adriaensen, Wim J; Matheï, Cathy; Buntinx, Frank J; Arbyn, Marc

2013-06-01

Screening tests are often introduced into clinical practice without proper evaluation, despite the increasing awareness that screening is a double-edged sword that can lead to either net benefits or harms. Our objective was to develop a comprehensive framework for the evaluation of new screening strategies. Elaborating on the existing concepts proposed by experts, a stepwise framework is proposed to evaluate whether a potential screening test can be introduced as a screening strategy into clinical practice. The principle of screening strategy evaluation is illustrated for cervical cancer, which is a template for screening because of the existence of an easily detectable and treatable precursor lesion. The evaluation procedure consists of six consecutive steps. In steps 1-4, the technical accuracy, place of the test in the screening pathway, diagnostic accuracy, and longitudinal sensitivity and specificity of the screening test are assessed. In steps 5 and 6, the impact of the screening strategy on the patient and population levels, respectively, is evaluated. The framework incorporates a harm and benefit trade-off and cost-effectiveness analysis. Our framework provides an outline toward the proper evaluation of potential screening strategies before considering implementation. Copyright © 2013 Elsevier Inc. All rights reserved.

Optimal catalyst curves: Connecting density functional theory calculations with industrial reactor design and catalyst selection

DEFF Research Database (Denmark)

Jacobsen, C.J.H.; Dahl, Søren; Boisen, A.

2002-01-01

For ammonia synthesis catalysts a volcano-type relationship has been found experimentally. We demonstrate that by combining density functional theory calculations with a microkinetic model the position of the maximum of the volcano curve is sensitive to the reaction conditions. The catalytic...... ammonia synthesis activity, to a first approximation, is a function only of the binding energy of nitrogen to the catalyst. Therefore, it is possible to evaluate which nitrogen binding energy is optimal under given reaction conditions. This leads to the concept of optimal catalyst curves, which illustrate...... the nitrogen binding energies of the optimal catalysts at different temperatures, pressures, and synthesis gas compositions. Using this concept together with the ability to prepare catalysts with desired binding energies it is possible to optimize the ammonia process. In this way a link between first...

Design and evaluation of new overview screens for the LABIHS simulator

International Nuclear Information System (INIS)

Oliveira, Mauro V.; Almeida, Jose C.S.; Jaime, Guilherme D.G.; Augusto, Silas C.

2015-01-01

The development and evaluation of Human-System Interfaces (HSIs) for control rooms is a research area at the Human-System Interface Laboratory (LABIHS). The main objective of this laboratory is to develop and evaluate projects of HSIs for industrial plants using different methodology construction. The evaluation of the interfaces is carried out in the LABIHS simulator at the Nuclear Engineering Institute (IEN). Previous evaluation of the overview screen of the nuclear power plant (NPP) simulator of the LABIHS showed the necessity of additional information to reduce the operator workload. To overcome this issue, a set of three 52-inch LCD TV was acquired to replace the projector in the task of showing the overview screen to the simulator operators. A new set of screens was developed to gather information in the three LCD screens. The approach used on the development of the new screens was based on human factors guidelines and recommendations. The objective of this work is present the design of these new overview screens and to evaluate their contribution to reduce the operators mental workload in this new scenario. (author)

Biological Evaluations of an Off-Stream Channel, Horizontal Flat-Plate Fish Screen-The Farmers Screen

Science.gov (United States)

Mesa, Matthew G.; Rose, Brien P.; Copeland, Elizabeth S.

2010-01-01

Screens are commonly installed at water diversion sites to reduce entrainment of fish. Recently, the Farmers Irrigation District in Hood River, Oregon, developed a new flat-plate screen design that offers passive operation and may result in reduced operation and installation costs to irrigators. To evaluate the performance (its biological effect on fish) of this type of screen, two size classes of juvenile coho salmon (Oncorhynchus kistuch) were released over a small version of this screen in the field-the Herman Creek screen. The performance of the screen was evaluated over a range of inflow [0.02 to 0.42 m3/s (cubic meters per second)] and diversion flows (0.02 to 0.34 m3/s) at different weir wall heights. The mean approach velocities for the screen ranged from 0 to 5 cm/s (centimeters per second) and mean sweeping velocities ranged from 36 to 178 cm/s. Water depths over the screen surface ranged from 1 to 25 centimeters and were directly related to weir wall height and inflow. Passage of juvenile coho salmon over the screen under a variety of hydraulic conditions did not severely injure them or cause delayed mortality. For all fish, the mean percentage of body surface area that was injured after passage over the screen ranged from about 0.4 to 3.0%. This occurred even though many fish contacted the screen surface during passage. No fish were observed becoming impinged on the screen surface (greater than 1 second contact with the screen). When operated within its design criteria (diversion flows of about 0.28 m3/s), the screen provided safe and effective downstream passage of juvenile salmonids under a variety of hydraulic conditions. However, we do not recommend operating the screen at inflows less than 0.14 m3/s (5 ft3/s) because water depth can get quite shallow and the screen can completely dewater, particularly at very low flows.

High-Throughput Screening Using Fourier-Transform Infrared Imaging

Directory of Open Access Journals (Sweden)

Erdem Sasmaz

2015-06-01

Full Text Available Efficient parallel screening of combinatorial libraries is one of the most challenging aspects of the high-throughput (HT heterogeneous catalysis workflow. Today, a number of methods have been used in HT catalyst studies, including various optical, mass-spectrometry, and gas-chromatography techniques. Of these, rapid-scanning Fourier-transform infrared (FTIR imaging is one of the fastest and most versatile screening techniques. Here, the new design of the 16-channel HT reactor is presented and test results for its accuracy and reproducibility are shown. The performance of the system was evaluated through the oxidation of CO over commercial Pd/Al2O3 and cobalt oxide nanoparticles synthesized with different reducer-reductant molar ratios, surfactant types, metal and surfactant concentrations, synthesis temperatures, and ramp rates.

Catalyst synthesis and evaluation using an integrated atomic layer deposition synthesis–catalysis testing tool

International Nuclear Information System (INIS)

Camacho-Bunquin, Jeffrey; Shou, Heng; Marshall, Christopher L.; Aich, Payoli; Beaulieu, David R.; Klotzsch, Helmut; Bachman, Stephen; Hock, Adam; Stair, Peter

2015-01-01

An integrated atomic layer deposition synthesis-catalysis (I-ALD-CAT) tool was developed. It combines an ALD manifold in-line with a plug-flow reactor system for the synthesis of supported catalytic materials by ALD and immediate evaluation of catalyst reactivity using gas-phase probe reactions. The I-ALD-CAT delivery system consists of 12 different metal ALD precursor channels, 4 oxidizing or reducing agents, and 4 catalytic reaction feeds to either of the two plug-flow reactors. The system can employ reactor pressures and temperatures in the range of 10 −3 to 1 bar and 300–1000 K, respectively. The instrument is also equipped with a gas chromatograph and a mass spectrometer unit for the detection and quantification of volatile species from ALD and catalytic reactions. In this report, we demonstrate the use of the I-ALD-CAT tool for the synthesis of platinum active sites and Al 2 O 3 overcoats, and evaluation of catalyst propylene hydrogenation activity

Catalyst synthesis and evaluation using an integrated atomic layer deposition synthesis–catalysis testing tool

Energy Technology Data Exchange (ETDEWEB)

Camacho-Bunquin, Jeffrey; Shou, Heng; Marshall, Christopher L. [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Aich, Payoli [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Beaulieu, David R.; Klotzsch, Helmut; Bachman, Stephen [Arradiance Inc., Sudbury, Massachusetts 01776 (United States); Hock, Adam [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Stair, Peter [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)

2015-08-15

An integrated atomic layer deposition synthesis-catalysis (I-ALD-CAT) tool was developed. It combines an ALD manifold in-line with a plug-flow reactor system for the synthesis of supported catalytic materials by ALD and immediate evaluation of catalyst reactivity using gas-phase probe reactions. The I-ALD-CAT delivery system consists of 12 different metal ALD precursor channels, 4 oxidizing or reducing agents, and 4 catalytic reaction feeds to either of the two plug-flow reactors. The system can employ reactor pressures and temperatures in the range of 10{sup −3} to 1 bar and 300–1000 K, respectively. The instrument is also equipped with a gas chromatograph and a mass spectrometer unit for the detection and quantification of volatile species from ALD and catalytic reactions. In this report, we demonstrate the use of the I-ALD-CAT tool for the synthesis of platinum active sites and Al{sub 2}O{sub 3} overcoats, and evaluation of catalyst propylene hydrogenation activity.

Evaluation of mammographic screen-film combinations in the clinic

International Nuclear Information System (INIS)

Shepard, J.

1987-01-01

Six commercially available mammographic film-screen combinations were evaluated in the authors department. Film speed and contrast was measured by obtaining H and D curves. Sensitivity to processing conditions was determined by analyzing changes in the H and D cures as a function of development time and temperature and by examining artifacts in a uniformly exposed film. Radiographs of a 0.5 0 star pattern show relative screen unsharpness. The speed of the film-screen combination is indicated by calculating patient dose necessary to produce optical densities of 1.5 through phantom thicknesses of 3.5 cm of acrylic. Images of a modified RMI detail phantom obtained with each film-screen combination were evaluated by 22 radiologist. Results indicate the physicians' overall preference

Oxidative desulfurization of synthetic diesel using supported catalysts. Part 3. Support effect on vanadium-based catalysts

Energy Technology Data Exchange (ETDEWEB)

Cedeno-Caero, Luis; Gomez-Bernal, Hilda; Fraustro-Cuevas, Adriana; Guerra-Gomez, Hector D.; Cuevas-Garcia, Rogelio [UNICAT, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria 04510, Mexico D.F. (Mexico)

2008-04-15

Oxidesulfurization (ODS) of benzothiophenic compounds prevailing in diesel was conducted with hydrogen peroxide in presence of various catalysts, using a model diesel and actual diesel fuel. ODS activities of dibenzothiophenes (DBTs) in hexadecane for a series of V{sub 2}O{sub 5} catalysts supported on alumina, titania, ceria, niobia and silica, were evaluated. Results show that the oxidation activity of DBTs depends on the support used. It was observed that the sulfone yield is not proportional to textural properties or V content. For all catalysts, ODS of benzothiophene (BT), dibenzothiophene (DBT), 4-methyl dibenzothiophene (4-MDBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) decreased in the following order: DBT > 4-MDBT > 4,6-DMDBT > BT. This trend does not depend on the catalyst used or the textural properties of the catalysts and supports. In presence of indole ODS activities diminish, except with catalysts supported on alumina-titania mixed oxide, whereas with V{sub 2}O{sub 5}/TiO{sub 2} catalyst the performance is the highest. ODS of Mexican diesel fuel was carried out in presence of this catalyst and S level was diminished in about 99%. (author)

Transformative learning theory: facilitating mammography screening in rural women.

Science.gov (United States)

Purtzer, Mary Anne; Overstreet, Lindsey

2014-03-01

To use transformative learning to investigate what experiences serve as catalysts for mammography screening, the cognitive and affective responses that result from the catalyst, and how screening behavior is impacted. A descriptive qualitative study. Southeastern Wyoming. 25 low-income, rural women aged 40 years and older. Four focus group interviews. Cancer experiences triggered universal responses of fear by screeners and nonscreeners. The manner in which that fear response was interpreted was a critical factor in the facilitation of, or impedance to, screening. Dichotomous interpretations of fear responses provided the context for screening behavior. Immobilizing and isolating experiences were associated with nonscreening behavior, whereas motivation and self-efficacy were associated with screening behavior. Transformative learning theory is a useful framework from which to explain differences in mammography screening behavior. Creating opportunities that facilitate dialogue and critical reflection hold the potential to change immobilizing and isolating frames of reference in nonscreening women. To help women transcend their fear and become self-efficacious, nurses can assess how cancer and the screening experience is viewed and, if indicated, move beyond standard education and offer opportunities for dialogue and critical reflection.

In silico search for novel methane steam reforming catalysts

DEFF Research Database (Denmark)

Xu, Yue; Lausche, Adam C; Wang, Shengguang

2013-01-01

App’) with a microkinetic modeling technique to predict the rates and selectivities of a prospective material. This paper illustrates this screening technique using the steam reforming of methane to carbon monoxide and hydrogen as a test reaction. While catalysts are already commercially available for this process...

Evaluation of teachers' performance of vision screening in primary

African Journals Online (AJOL)

Dr. Petronilla

Evaluation of Teachers' Performance of Vision Screening in Primary. School Children in Port ... teachers can effectively perform vision screening in school children using ..... may be due to variations in methodology and definitions used, as this ...

Oxidation catalyst

Science.gov (United States)

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.

Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

Directory of Open Access Journals (Sweden)

Galip Akay

2016-05-01

Full Text Available A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state can be controlled from a few seconds to several minutes. The resulting nano-structured micro-porous silica supported catalyst system has a surface area approaching 300 m2/g and X-ray Diffraction (XRD-based catalyst size controlled in the range of 1–10 nm in which the catalyst structure appears as lamellar sheets sandwiched between the catalyst support. These catalyst characteristics are dependent primarily on the processing history as well as the catalyst (Fe, Co and Ni studied when the catalyst/support molar ratio is typically 0.1–2. In addition, Ca, Mn and Cu were used as co-catalysts with Fe and Co in the evaluation of the mechanism of catalyst generation. Based on extensive XRD, Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM studies, the micro- and nano-structure of the catalyst system were evaluated. It was found that the catalyst and silica support form extensive 0.6–2 nm thick lamellar sheets of 10–100 nm planar dimensions. In these lamellae, the alternate silica support and catalyst layer appear in the form of a bar-code structure. When these lamellae structures pack, they form the walls of a micro-porous catalyst system which typically has a density of 0.2 g/cm3. A tentative mechanism of catalyst nano-structure formation is provided based on the rheology and fluid mechanics of the catalyst/support precursor fluid as well as co-assembly nano-reactor formation during processing. In order to achieve these structures and characteristics, catalyst support must be in the form of silane coated silica nano

Breast cancer screening-opportunistic use of registry and linked screening data for local evaluation.

Science.gov (United States)

Roder, David; Farshid, Gelareh; Gill, Grantley; Kollias, Jim; Koczwara, Bogda; Karapetis, Chris; Adams, Jacqui; Joshi, Rohit; Keefe, Dorothy; Powell, Kate; Fusco, Kellie; Eckert, Marion; Buckley, Elizabeth; Beckmann, Kerri

2017-06-01

Screening has been found to reduce breast cancer mortality at a population level in Australia, but these studies did not address local settings where numbers of deaths would generally have been too low for evaluation. Clinicians, administrators, and consumer groups are also interested in local service outcomes. We therefore use more common prognostic and treatment measures and survivals to gain evidence of screening effects among patients attending 4 local hospitals for treatment. To compare prognostic, treatment, and survival measures by screening history to determine whether expected screening effects are occurring. Employing routine clinical registry and linked screening data to investigate associations of screening history with these measures, using unadjusted and adjusted analyses. Screened women had a 10-year survival from breast cancer of 92%, compared with 78% for unscreened women; and 79% of screened surgical cases had breast conserving surgery compared with 64% in unscreened women. Unadjusted analyses indicated that recently screened cases had earlier tumor node metastasis stages, smaller diameters, less nodal involvement, better tumor differentiation, more oestrogen and progesterone receptor positive lesions, more hormone therapy, and less chemotherapy. Radiotherapy tended to be more common in screening participants. More frequent use of adjunctive radiotherapy applied when breast conserving surgery was used. Results confirm the screening effects expected from the scientific literature and demonstrate the value of opportunistic use of available registry and linked screening data for indicating to local health administrations, practitioners, and consumers whether local screening services are having the effects expected. © 2016 John Wiley & Sons, Ltd.

Productions of palm oil bio diesel whit heterogeneous basic catalysts compared to conventional homogeneous catalysts

International Nuclear Information System (INIS)

Rios, Luis A; Franco C, Alexander; Zuleta S, Ernesto

2009-01-01

The conventional process to produce biodiesel involves the presence of homogeneous basic catalysts. However, these catalysts have disadvantages associated to the need of purification steps, which increase the cost of the final product and generate pollution problems caused by the effluents. This paper compares different homogeneous and heterogeneous catalysts for the biodiesel production from palm oil. For this, heterogeneous catalysts supported on alumina were prepared and characterized by nitrogen adsorption, scanning electron microscopy, energy dispersive X ray spectroscopy and X ray diffraction. Transesterification of palm oil with methanol was accomplished at 60 celsius degrade and one hour, varying methanol/oil ratio, the type of catalyst and its concentration. Yields of the reaction and purity of the so obtained biodiesel were evaluated. Comparing the catalysts performance, based on the amount, was found that sodium methoxide (CH 3 ONa) and potassium carbonate supported on alumina (K 2 CO 3 /Al 2 O 3 ) were the catalysts that give the higher purity of biodiesel (96.8 and 95.85% respectively). When was determined the active site quality, by dividing the performance by each mole of active sites, it was found that calcined Na 2 SO 4 /Al 2 O 3 has the most active sites.

Preparation of hydrophobic Pt-catalysts for decontamination of nuclear effluents

International Nuclear Information System (INIS)

Ionita, Gh.; Popescu, I.; Retegan, T.; Stefanescu, I.

2005-01-01

Based on the long experience of the authors, in the preparation, testing and evaluation of the performances of hydrophobic catalysts, and based on the reviewed references, this paper presents up-to-date R and D activities on the preparation methods and applications of the hydrophobic catalysts, in deuterium and tritium separation. The objectives of the paper are: (1) to provide a database for selection of the most appropriate catalyst and catalytic packing for above mentioned processes, (2) to evaluate the potentiality of hydrophobic Pt-catalysts in the deuterium and tritium separation (3) to asses and to find a new procedure for preparation a new improved hydrophobic catalyst. The merits of the hydrophobic catalysts are shown in comparison to hydrophilic catalysts. As results of the review some general conclusions about the applications of hydrophobic catalysts in environmental field are as follow: (1) the hydrophobic Pt-catalysts packed in the trickle bed reactors showed a high catalytic activity and long stability; (2) the utilization of the hydrophobic Pt-catalysts for tritium removal from liquid and gaseous effluent in nuclear field was entirely confirmed on industrial scale; (3) the extension of the utilization of the hydrophobic Pt-catalysts in other new processes, which take place in presence of liquid water or high humidity are subjected to testing. (author)

Preparation of hydrophobic Pt-catalysts for decontamination of nuclear effluents

International Nuclear Information System (INIS)

Ionita, Gh.; Popescu, I.; Retegan, T.; Stefanescu, I.

2004-01-01

Based on the long experience of the authors, in the preparation, testing and evaluation of the performances of hydrophobic catalysts, and based on the reviewed references, this paper presents up-to-date R and D activities on the preparation methods and applications of the hydrophobic catalysts, in deuterium and tritium separation. The objectives of the paper are: - to provide a database for selection of the most appropriate catalyst and catalytic packing for above mentioned processes; - to evaluate the potentiality of hydrophobic Pt-catalysts in the deuterium and tritium separation; - to assess and to find a new procedure for preparation a new improved hydrophobic catalyst. The merits of the hydrophobic catalysts are shown in comparison to hydrophilic catalysts. As results of the review some general conclusions about the applications of hydrophobic catalysts in environmental field are as follows: - the hydrophobic Pt-catalysts packed in the trickle bed reactors showed a high catalytic activity and long stability; - the utilization of the hydrophobic Pt-catalysts for tritium removal from liquid and gaseous effluent in nuclear field was entirely confirmed on industrial scale; - the extension of the utilization of the hydrophobic Pt-catalysts in other new processes, which take place in presence of liquid water or high humidity are subject to testing. (authors)

Use of hydrophobic Pt-catalysts in tritium removal from effluents

International Nuclear Information System (INIS)

Gheorghe, Ionita; Popescu, Irina; Stefanescu, Ioan; Steflea, Dumitru; Varlam, Carmen

2002-01-01

Based on the long experience of the authors, in the preparation, testing and evaluation of the performances of hydrophobic catalysts, and based on the reviewed references, this paper presents up-to-date R and D activities on the application of the hydrophobic catalysts in tritium removal from nuclear effluents. Tritium removal from the heavy water reactor and nuclear reprocessing plant, the cleanup of atmosphere and gaseous effluents by hydrogen-oxygen recombination, removal of oxygen dissolved in water are presented and discussed. Unlike the conventional hydrophilic catalysts, the hydrophobic catalysts keep a high catalytic activity and stability, even under the direct contact to liquid water or in presence of saturated humidity. A large diversity of catalyst types (over 100 catalysts) was prepared and tested in order to make them feasible for such processes. The objectives of the review are: - to provide a database for selection of the most appropriate catalyst and catalytic packing for above mentioned processes; - the designing and operation of reactor packed with hydrophobic catalysts; - to evaluate the potentiality of hydrophobic Pt-catalysts in the present and future applications. The most important results are the following: - the hydrophobic Pt-catalysts packed in the trickle bed or separated bed reactors, showed a high catalytic activity and long stability; - the utilization of the hydrophobic Pt-catalysts for the hydrogen isotopes (tritium and deuterium) separation and for hydrogen-oxygen recombination in nuclear field was entirely confirmed on industrial scale; - the improvement of the inner geometry of the reactors and of the composition of mixed catalytic packing as well as the evaluation of performances of separation processes constitute a major contribution of the authors; - the extension of the utilization of the hydrophobic Pt-catalysts in the oxidation of volatile organic compounds from wastewater; - the removal of dissolved oxygen, and deuterium

40 CFR 91.329 - Catalyst thermal stress test.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress test. 91.329....329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for termally stressing the test catalyst must be capable of maintaining a temperature of 500 ±5 °C and 1000 ±10 °C. (b) Evaluation...

Synthesis and Electrochemical Evaluation of Carbon Supported Pt-Co Bimetallic Catalysts Prepared by Electroless Deposition and Modified Charge Enhanced Dry Impregnation

Directory of Open Access Journals (Sweden)

John Meynard M. Tengco

2016-06-01

Full Text Available Carbon-supported bimetallic Pt-Co cathode catalysts have been previously identified as higher activity alternatives to conventional Pt/C catalysts for fuel cells. In this work, a series of Pt-Co/C catalysts were synthesized using electroless deposition (ED of Pt on a Co/C catalyst prepared by modified charge enhanced dry impregnation. X-ray diffraction (XRD and scanning transmission electron microscopy (STEM characterization of the base catalyst showed highly dispersed particles. A basic ED bath containing PtCl62− as the Pt precursor, dimethylamine borane as reducing agent, and ethylenediamine as stabilizing agent successfully targeted deposition of Pt on Co particles. Simultaneous action of galvanic displacement and ED resulted in Pt-Co alloy formation observed in XRD and energy dispersive X-ray spectroscopy (XEDS mapping. In addition, fast deposition kinetics resulted in hollow shell Pt-Co alloy particles while particles with Pt-rich shell and Co-rich cores formed with controlled Pt deposition. Electrochemical evaluation of the Pt-Co/C catalysts showed lower active surface but much higher mass and surface activities for oxygen reduction reaction compared to a commercial Pt/C fuel cell catalyst.

Optimization of catalyst system reaps economic benefits

International Nuclear Information System (INIS)

Le Roy, C.F.; Hanshaw, M.J.; Fischer, S.M.; Malik, T.; Kooiman, R.R.

1991-01-01

Champlin Refining and Chemicals Inc. is learning to optimize its catalyst systems for hydrotreating Venezuelan gas oils through a program of research, pilot plant testing, and commercial unit operation. The economic results of this project have been evaluated, and the benefits are most evident in improvements in product yields and qualities. The project has involved six commercial test runs, to date (Runs 10-15), with a seventh run planned. A summary of the different types of catalyst systems used in the test runs, and the catalyst philosophy that developed is given. Runs 10 and 11 used standard CoMo and NiMo catalysts for heavy gas oils hydrotreating. These catalysts had small pore sizes and suffered high deactivation rates because of metals contamination. When it was discovered that metals contamination was a problem, catalyst options were reviewed

Coanda hydro intake screen testing and evaluation

Energy Technology Data Exchange (ETDEWEB)

Howarth, J.

2001-07-01

The objective of this project has been to evaluate the effectiveness, suitability and cost benefit of the Aquashear Coanda effect, maintenance free intake screen for use in small hydro system intakes. (author)

Benefit-risk evaluation of mammographic mass screening

International Nuclear Information System (INIS)

Sato, Nobuo; Ogura, Toshihiro

1990-01-01

This study evaluated the benefit-risk balance of mammography in mass screening by using survival rates from 3000 breast cancer patients at the Japanese Foundation for Cancer Research Institute Hospital. Because the number of participants in mammographic mass screening was small, asymptomatic patients with pathologically proven early breast cancer were categorized as the screenee group. Symptomatic patients were categorized as the patient group. Survival rates were compared in both the screenee and the patient groups. Based on the difference in areas of survival curves between screenees and patients, the ratio of person-year gain (PYG) to person-year lost (PYL) was obtained. The ratio of PYG to PYL was multiplied by the detection rate resulting from a particular screening program to obtain the benefit/risk ratio. The detection rate of nonpalpable breast cancer was 15 times higher in the screenee group than the patient group. Breast cancer was detected in 7 (0.85%) of 824 patients in the screenee group. Even when mammographic mass screening was started at the age of 30, the benefit of mammography was far superior to the risk. The number of participants in mass screening stratified by age may be required for the conclusion of the benefit-risk balance of mammography in mass screening. (N.K.)

Characterization of deactivated catalytic cracking catalyst and evaluation as absorbent material

International Nuclear Information System (INIS)

Valt, R.B.G.; Kaminari, N.M.S.; Cordeiro, B.; Ponte, M.J.J.S.; Ponte, H.A.

2010-01-01

One of the main uses of catalysts in the petroleum industry is in step catalytic cracking, which after use and regeneration cycles generates large quantities of waste material. In this research the deactivated FCC catalyst was characterized before and after the electrokinetic remediation process, in order to assess the change of its structure and possible adsorptive capacity. Analyses of X-Ray Fluorescence Spectroscopy, Scanning Electron Microscopy and BET surface area measurement were performed. The analysis showed no structural change due to the process employed and that electrokinetic remediation has recovered 42% of adsorption capacity of the material, by removing about 89% of heavy metals adhered initially in the catalyst surface. (author)

Medical screening and evaluation for heat stress

International Nuclear Information System (INIS)

Kenney, L.W.

1985-01-01

Wide interindividual variation exists with respect to heat tolerance, making it difficult to predict individual responses. However, several general physical and physiological characteristics are associated with excessive strain and early exhaustion during work in the heat. Included among these correlates of heat intolerance are a medical history of heat illness, acclimation state, age, body composition and size, aerobic fitness level, hypertension, and drug and alcohol use. The approach of choice for medical evaluation for heat exposure is a two-stage evaluation. First, the examining physician should be encouraged to screen out those workers whose characteristics increase their risk of heat intolerance. Secondly, a short exercise test is proposed which accurately predicts relative heat tolerance across a working population. This test is recommended as an adjunct screening test at the examining physician's disgression

Preconception carrier screening for multiple disorders: evaluation of a screening offer in a Dutch founder population.

Science.gov (United States)

Mathijssen, Inge B; Holtkamp, Kim C A; Ottenheim, Cecile P E; van Eeten-Nijman, Janneke M C; Lakeman, Phillis; Meijers-Heijboer, Hanne; van Maarle, Merel C; Henneman, Lidewij

2018-02-01

Technological developments have enabled carrier screening for multiple disorders. This study evaluated experiences with a preconception carrier screening offer for four recessive disorders in a Dutch founder population. Questionnaires were completed by 182 attendees pretesting and posttesting and by 137 non-attendees. Semistructured interviews were conducted with seven of the eight carrier couples. Attendees were mainly informed about the existence of screening by friends/colleagues (49%) and family members (44%). Familiarity with the genetic disorders was high. Knowledge after counseling increased (p influencers (family/friends) can be used to raise awareness of a screening offer. Our findings provide lessons for the implementation of expanded carrier screening panels in other communities and other settings.

Finding Furfural Hydrogenation Catalysts via Predictive Modelling

OpenAIRE

Strassberger, Zea; Mooijman, Maurice; Ruijter, Eelco; Alberts, Albert H; Maldonado, Ana G; Orru, Romano V A; Rothenberg, Gadi

2010-01-01

Abstract We combine multicomponent reactions, catalytic performance studies and predictive modelling to find transfer hydrogenation catalysts. An initial set of 18 ruthenium-carbene complexes were synthesized and screened in the transfer hydrogenation of furfural to furfurol with isopropyl alcohol complexes gave varied yields, from 62% up to >99.9%, with no obvious structure/activity correlations. Control experiments proved that the carbene ligand remains coordinated to the ruthenium centre t...

Screening of catalytic oxygen reduction reaction activity of metal-doped graphene by density functional theory

International Nuclear Information System (INIS)

Chen, Xin; Chen, Shuangjing; Wang, Jinyu

2016-01-01

Highlights: • The screened M-G structures are very thermodynamically stable, and the stability is even higher than that of the corresponding bulk metal surfaces. • The binding energies of ORR intermediates suggest that they are not linear dependence, which are different form the cases found on some metal-based catalysts. • The Au-, Co-, and Ag-G structures could be used as the ORR catalysts. - Abstract: Graphene doping is a promising direction for developing effective oxygen reduction reaction (ORR) catalysts. In this paper, we computationally investigated the ORR performance of 10 kinds of metal-doped graphene (M-G) catalysts, namely, Al-, Si-, Mn-, Fe-, Co-, Ni-, Pd-, Ag-, Pt-, and Au-G. The results shown that the binding energies of the metal atoms incorporated into the graphene vacancy are higher than their bulk cohesive energies, indicating the formed M-G catalysts are even more stable than the corresponding bulk metal surfaces, and thus avoid the metals dissolution in the reaction environment. We demonstrated that the linear relation among the binding energies of the ORR intermediates that found on metal-based materials does not hold for the M-G catalysts, therefore a single binding energy of intermediate alone is not sufficient to evaluate the ORR activity of an arbitrary catalyst. By analysis of the detailed ORR processes, we predicted that the Au-, Co-, and Ag-G materials can be used as the ORR catalysts.

A Multiscale Model Evaluates Screening for Neoplasia in Barrett's Esophagus.

Directory of Open Access Journals (Sweden)

Kit Curtius

2015-05-01

Full Text Available Barrett's esophagus (BE patients are routinely screened for high grade dysplasia (HGD and esophageal adenocarcinoma (EAC through endoscopic screening, during which multiple esophageal tissue samples are removed for histological analysis. We propose a computational method called the multistage clonal expansion for EAC (MSCE-EAC screening model that is used for screening BE patients in silico to evaluate the effects of biopsy sampling, diagnostic sensitivity, and treatment on disease burden. Our framework seamlessly integrates relevant cell-level processes during EAC development with a spatial screening process to provide a clinically relevant model for detecting dysplastic and malignant clones within the crypt-structured BE tissue. With this computational approach, we retain spatio-temporal information about small, unobserved tissue lesions in BE that may remain undetected during biopsy-based screening but could be detected with high-resolution imaging. This allows evaluation of the efficacy and sensitivity of current screening protocols to detect neoplasia (dysplasia and early preclinical EAC in the esophageal lining. We demonstrate the clinical utility of this model by predicting three important clinical outcomes: (1 the probability that small cancers are missed during biopsy-based screening, (2 the potential gains in neoplasia detection probabilities if screening occurred via high-resolution tomographic imaging, and (3 the efficacy of ablative treatments that result in the curative depletion of metaplastic and neoplastic cell populations in BE in terms of the long-term impact on reducing EAC incidence.

A new continuous-flow process for catalytic conversion of glycerol to oxygenated fuel additive: Catalyst screening

International Nuclear Information System (INIS)

Nanda, Malaya R.; Yuan, Zhongshun; Qin, Wensheng; Ghaziaskar, Hassan S.; Poirier, Marc-Andre; Xu, Chunbao

2014-01-01

Highlights: • A continuous-flow process for catalytic synthesis of solketal from glycerol. • Six different heterogeneous acid catalysts were studied in the process. • Glycerol conversion and solketal yield of 90% and 88% respectively were achieved. • The process has the potential to be scaled-up for industrial applications. - Abstract: A new continuous-flow reactor was designed for the conversion of glycerol to solketal, an oxygenated fuel additive, through ketalization with acetone. Six heterogeneous catalysts were investigated with respect to their catalytic activity and stability in a flow reactor. The acidity of the catalysts positively influences the catalyst’s activity. Among all the solid acid catalysts tested, the maximum solketal yield from experiments at 40 °C, 600 psi and WHSV of 4 h −1 attained 73% and 88% at the acetone/glycerol molar ratio of 2.0 and 6.0, respectively, with Amberlyst Wet. Based on the solketal yield and glycerol conversion results, the activity of all catalysts tested follows the following order of sequence: Amberlyst Wet ≈ Zeolite ≈ Amberlyst Dry > Zirconium Sulfate > Montmorillonite > Polymax. An increase in acetone/glycerol molar ratio or a decrease in WHSV enhanced the glycerol conversion as expected. This process offers an attractive route for converting glycerol, the main by-product of biodiesel, to solketal – a value-added green product with potential industrial applications as a valuable fuel additive or combustion promoter for gasoline engines

New sulfide catalysts for the hydroliquefaction of coal

NARCIS (Netherlands)

Vissers, J.P.R.; Oers, van E.M.; Beer, de V.H.J.; Prins, R.

1987-01-01

Possibilities for the preparation of new metal sulfide catalyst systems based on carbon carriers having favourable textural and surface properties have been explored, and attention has been given to the characterization (structure) and evaluation (hydrosulfurization activity) of these catalysts. Two

Screening criteria of volcanic hazards aspect in the NPP site evaluation

International Nuclear Information System (INIS)

Nur Siwhan

2013-01-01

Studies have been conducted on the completeness of regulation in Indonesia particularly on volcanic hazards aspects in the evaluation of nuclear power plant site. Volcanic hazard aspect needed to identify potential external hazards that may endanger the safety of the operation of nuclear power plants. There are four stages for evaluating volcanic hazards, which are initial assessment, characterization sources of volcanic activity in the future, screening volcanic hazards and assessment of capable volcanic hazards. This paper discuss the third stage of the general evaluation which is the screening procedure of volcanic hazards. BAPETEN Chairman Regulation No. 2 Year of 2008 has only one screening criteria for missile volcanic phenomena, so it required screening criteria for other hazard phenomena that are pyroclastic flow density; lava flows; avalanche debris materials; lava; opening hole new eruptions, volcano missile; tsunamis; ground deformation; and hydrothermal system and ground water anomaly. (author)

XPS analysis of supported catalysts prepared in water-in-oil microemulsion system

International Nuclear Information System (INIS)

Mohd Ambar Yarmo; Wong Hoi Jin; Tan Chew Khim; Anita Ramli; Shahidan Radiman

2002-01-01

Catalysts supported on γ-alumina prepared by water-in-oil microemulsion were studied by X-ray photoelectron spectroscopy for comparison with catalysts prepared by wet impregnation. Comparable shifts to higher binding energies indicated a metal-support interaction where metal obtained via microemulsion is very small in size and highly dispersed. The positive binding energy shifts could be explained from a net unit positive charge remaining on the cluster in the photoemission final state in addition to the metallic screening from a redistribution of states within the bands. (Author)

Third trimester screening for alloimmunisation in Rhc-negative pregnant women : evaluation of the Dutch national screening programme

NARCIS (Netherlands)

Slootweg, Y. M.; Koelewijn, J. M.; van Kamp, I. L.; van der Bom, J. G.; Oepkes, D.; de Haas, M.

ObjectiveTo evaluate the effect of red blood cell (RBC) antibody screening in the 27th week of pregnancy in Rhc-negative women, on detection of alloimmunisation, undetected at first trimester screening (late' alloimmunisation), and subsequent haemolytic disease of the fetus and newborn (HDFN), to

Follow up Evaluation of Air Force Blood Donors Screening Positive for Chagas Disease

Science.gov (United States)

2017-10-05

59 MDW/SGVU SUBJECT: Professional Presentation Approval 31 JULY2017 Your paper, entitled Follow-up Evaluation of Air Force Blood Donors Screening...PUBLISHED OR PRESENTED: Follow-up Evaluation of Air Force Blood Donors Screening Positive for Chagas Disease 7. FUNDING RECEIVED FOR THIS STUDY? 0...PREVIOUS EDITIONS ARE OBSOLETE 50. DATE Page 3 of 3 Pages Follow-up Evaluation of Air Force Blood Donors Screening Positive for Chagas Disease

High-throughput heterogeneous catalyst research

Science.gov (United States)

Turner, Howard W.; Volpe, Anthony F., Jr.; Weinberg, W. H.

2009-06-01

With the discovery of abundant and low cost crude oil in the early 1900's came the need to create efficient conversion processes to produce low cost fuels and basic chemicals. Enormous investment over the last century has led to the development of a set of highly efficient catalytic processes which define the modern oil refinery and which produce most of the raw materials and fuels used in modern society. Process evolution and development has led to a refining infrastructure that is both dominated and enabled by modern heterogeneous catalyst technologies. Refineries and chemical manufacturers are currently under intense pressure to improve efficiency, adapt to increasingly disadvantaged feedstocks including biomass, lower their environmental footprint, and continue to deliver their products at low cost. This pressure creates a demand for new and more robust catalyst systems and processes that can accommodate them. Traditional methods of catalyst synthesis and testing are slow and inefficient, particularly in heterogeneous systems where the structure of the active sites is typically complex and the reaction mechanism is at best ill-defined. While theoretical modeling and a growing understanding of fundamental surface science help guide the chemist in designing and synthesizing targets, even in the most well understood areas of catalysis, the parameter space that one needs to explore experimentally is vast. The result is that the chemist using traditional methods must navigate a complex and unpredictable diversity space with a limited data set to make discoveries or to optimize known systems. We describe here a mature set of synthesis and screening technologies that together form a workflow that breaks this traditional paradigm and allows for rapid and efficient heterogeneous catalyst discovery and optimization. We exemplify the power of these new technologies by describing their use in the development and commercialization of a novel catalyst for the

Catalyst dispersion and activity under conditions of temperature-staged liquefaction

Energy Technology Data Exchange (ETDEWEB)

Davis, A.; Schobert, H.H.; Mitchell, G.D.; Artok, L.

1993-02-01

This research program involves the investigation of the use of highly dispersed catalyst precursors for the pretreatment of coals by mild hydrogenation. During the course of this effort solvent preswelling of the coal was evaluated as a means of deeply impregnating catalysts into coal, active phases of catalysts under reaction conditions were studied and the impact of these techniques were evaluated during pretreatment and temperature-staged liquefaction. Two coals, a Texas subbituminous and a Utah high volatile A bituminous, were used to examine the effects of solvent swelling pretreatment and catalyst impregnation on conversion behavior at 275[degrees]C, representative of the first, low-temperature stage in a temperature-staged liquefaction reaction. Ferrous sulfate, iron pentacarbonyl, ammonium tetrathiomolybdate, and molybdenum hexacarbonyl were used as catalyst precursors. Without swelling pretreatment, impregnation of both coals increased conversion, mainly through increased yields of preasphaltenes.

Recycling of platinum group metals from the automotive catalysts

International Nuclear Information System (INIS)

Benevit, Mariana; Petter, Patricia Melo Halmenschlager; Veit, Hugo Marcelo

2014-01-01

Currently it is very important to use alternative sources of raw material for obtaining metals, avoiding the traditional mining. This work aims to characterize and evaluate the recoverability of platinum group metals present in automotive catalysts. Thus, the catalysts were divided into two groups: the first was catalysts used in 1.0 cars and the second was catalyst used in 2.0 cars. DRX and FRX techniques and chemical analysis performed by ICP/OES was used to characterized these materials. The results showed that there is a significant amount of platinum group elements in catalyst waste, which can be separated and reused. In the next step, hydro and pyrometallurgical routes, for metals extraction from catalyst waste, will be studied. (author)

Catalysts, methods of making catalysts, and methods of use

KAUST Repository

Renard, Laetitia; El Eter, Mohamad; Caps, Valerie; Basset, Jean-Marie

2014-01-01

Embodiments of the present disclosure provide for catalysts, methods of making catalysts, methods of using catalysts, and the like. In an embodiment, the method of making the catalysts can be performed in a single step with a metal nanoparticle precursor and a metal oxide precursor, where a separate stabilizing agent is not needed.

Catalysts, methods of making catalysts, and methods of use

KAUST Repository

Renard, Laetitia

2014-03-06

Embodiments of the present disclosure provide for catalysts, methods of making catalysts, methods of using catalysts, and the like. In an embodiment, the method of making the catalysts can be performed in a single step with a metal nanoparticle precursor and a metal oxide precursor, where a separate stabilizing agent is not needed.

Evaluation of alumina-aluminium phosphate catalyst supports for hydrodenitrogenation of pyridine and coal-derived liquids

Energy Technology Data Exchange (ETDEWEB)

Menon, R.; Joo, H.S.; Guin, J.A.; Reucroft, P.J.; Kim, J.Y. [Auburn University, Auburn, AL (United States). Dept. of Chemical Engineering

1996-05-01

Several alumina-aluminum phosphate (AAP) catalyst supports were prepared by a coprecipitation method. Effect of variations in Al/P atomic ratios on support textural properties were examined. Finished NiMo/AAP catalysts containing nominally 3 wt% Ni and 13 wt% Mo were prepared by incipient wetness and characterized by several methods including elemental, BET, and XPS surface analysis. Initial hydrodenitrogenation (HDN) activities of the catalysts were examined in both pyridine model compound and coal liquid reactions. The AAP supports showed the opportunity to tailor the catalyst pore size by variation of the Al/P ratio. On a per unit surface areas basis, the AAP-supported catalysts had initial HDN activities comparable to those of a commercial P-promoted NiMo/Al{sub 2}O{sub 3} catalyst. Because of their unique textural properties, i.e. variable pore sizes, the AAP catalysts may offer advantages when dealing with macromolecular feedstocks where hindered diffusion may slow reaction rates. 37 refs., 8 figs., 6 tabs.

SSZ-13-supported manganese oxide catalysts for low temperature ...

Indian Academy of Sciences (India)

YONGZHOU YE

Their performances for the selective catalytic reduction (SCR) of NOx with NH3 were evaluated. ... catalysts have received considerable attention.2,3 More- over, catalysts ..... zeolite channels or causing agglomeration on the cat- alyst surface ...

Solar-assisted photodegradation of isoproturon over easily recoverable titania catalysts.

Science.gov (United States)

Tolosana-Moranchel, A; Carbajo, J; Faraldos, M; Bahamonde, A

2017-03-01

An easily recoverable homemade TiO 2 catalyst (GICA-1) has been evaluated during the overall photodegradation process, understood as photocatalytic efficiency and catalyst recovery step, in the solar light-assisted photodegradation of isoproturon and its reuse in two consecutive cycles. The global feasibility has been compared to the commercial TiO 2 P25. The homemade GICA-1 catalyst presented better sedimentation efficiency than TiO 2 P25 at all studied pHs, which could be explained by its higher average hydrodynamic particle size (3 μm) and other physicochemical surface properties. The evaluation of the overall process (isoproturon photo-oxidation + catalyst recovery) revealed GICA-1 homemade titania catalyst strengths: total removal of isoproturon in less than 60 min, easy recovery by sedimentation, and reusability in two consecutive cycles, without any loss of photocatalytic efficiency. Therefore, considering the whole photocatalytic cycle (good performance in photodegradation plus catalyst recovery step), the homemade GICA-1 photocatalyst resulted in more affordability than commercial TiO 2 P25. Graphical abstract.

Deactivation-resistant catalyst for selective catalyst reduction of NOx

DEFF Research Database (Denmark)

2011-01-01

The present invention relates to a catalyst for selective catalytic reduction of NOx in alkali metal containing flue gas using ammonia as reductant, the catalyst comprising a surface with catalytically active sites, wherein the surface is at least partly coated with a coating comprising at least...... one metal oxide. In another aspect the present invention relates to the use of said catalyst and to a method of producing said catalyst. In addition, the present invention relates to a method of treating an catalyst for conferring thereon an improved resistance to alkali poisoning....

Session 4: Combinatorial research of methane catalytic decomposition on supported nitride catalysts for CO-free hydrogen

Energy Technology Data Exchange (ETDEWEB)

Jianghan, Shen; Hua, Wang; Zhongmin, Liu; Hongchao, Liu [Natural Gas Utilization and Applied Catalysis Lab., Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian P. R. (China)

2004-07-01

CO-free Hydrogen production is needed for proton exchange membrane fuel cells (PEMs) because CO strongly poisons the anode-electrocatalysts. Methane directly catalytic decomposition is an attractive way to produce CO-free hydrogen for the large abundance of methane and its high H/C ratio. It is more effective to employ high-throughput screening (HTS) technology in heterogeneous catalysis. In this paper, a combinatorial multi-stream reaction system with online multi-stream mass spectrometer screening (MSMSS) detection technique was applied to study the decomposition of methane over supported MoN{sub x}O{sub y} catalysts (supports = Al{sub 2}O{sub 3}, SiO{sub 2}, SBA-15, ZSM-5,13X, and NaY), which is a catalyst system seldom reported recently. (authors)

D & D screening risk evaluation guidance

Energy Technology Data Exchange (ETDEWEB)

Robers, S.K.; Golden, K.M.; Wollert, D.A.

1995-09-01

The Screening Risk Evaluation (SRE) guidance document is a set of guidelines provided for the uniform implementation of SREs performed on decontamination and decommissioning (D&D) facilities. Although this method has been developed for D&D facilities, it can be used for transition (EM-60) facilities as well. The SRE guidance produces screening risk scores reflecting levels of risk through the use of risk ranking indices. Five types of possible risk are calculated from the SRE: current releases, worker exposures, future releases, physical hazards, and criticality. The Current Release Index (CRI) calculates the current risk to human health and the environment, exterior to the building, from ongoing or probable releases within a one-year time period. The Worker Exposure Index (WEI) calculates the current risk to workers, occupants and visitors inside contaminated D&D facilities due to contaminant exposure. The Future Release Index (FRI) calculates the hypothetical risk of future releases of contaminants, after one year, to human health and the environment. The Physical Hazards Index (PHI) calculates the risks to human health due to factors other than that of contaminants. Criticality is approached as a modifying factor to the entire SRE, due to the fact that criticality issues are strictly regulated under DOE. Screening risk results will be tabulated in matrix form, and Total Risk will be calculated (weighted equation) to produce a score on which to base early action recommendations. Other recommendations from the screening risk scores will be made based either on individual index scores or from reweighted Total Risk calculations. All recommendations based on the SRE will be made based on a combination of screening risk scores, decision drivers, and other considerations, as determined on a project-by-project basis.

A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

KAUST Repository

Poater, Albert; Cavallo, Luigi

2015-01-01

During a Ru-catalyzed reaction of an olefin with an alkylidene moiety that leads to a metallacycle intermediate, the cis insertion of the olefin can occur from two different directions, namely side and bottom with respect to the phosphine or N-heterocyclic ligand (NHC), depending on the first or second generation Grubbs catalyst. Here, DFT calculations unravel to which extent the bottom coordination of olefins with respect is favored over the side coordination through screening a wide range of catalysts, including first and second generation Grubbs catalysts as well as the subsequent Hoveyda derivatives. The equilibrium between bottom and side coordination is influenced by sterics, electronics, and polarity of the solvent. The side attack is favored for sterically less demanding NHC and/or alkylidene ligands. Moreover the generation of a 14-electron species is also discussed, with either pyridine or phosphine ligands to dissociate.

A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

KAUST Repository

Poater, Albert

2015-09-29

During a Ru-catalyzed reaction of an olefin with an alkylidene moiety that leads to a metallacycle intermediate, the cis insertion of the olefin can occur from two different directions, namely side and bottom with respect to the phosphine or N-heterocyclic ligand (NHC), depending on the first or second generation Grubbs catalyst. Here, DFT calculations unravel to which extent the bottom coordination of olefins with respect is favored over the side coordination through screening a wide range of catalysts, including first and second generation Grubbs catalysts as well as the subsequent Hoveyda derivatives. The equilibrium between bottom and side coordination is influenced by sterics, electronics, and polarity of the solvent. The side attack is favored for sterically less demanding NHC and/or alkylidene ligands. Moreover the generation of a 14-electron species is also discussed, with either pyridine or phosphine ligands to dissociate.

Antifungal evaluation and phytochemical screening of methanolic ...

African Journals Online (AJOL)

The objective of the study was to further examine the medicinal value of Boswellia dalzielii plant by evaluating the antifungal activity and carrying out phytochemical screening of methanolic extract, hexane, ethyl acetate, aqueous fractions and the sub-fractions of the stem bark of the plant. Standard methods were used for ...

Monitored retrievable storage facility site screening and evaluation report

International Nuclear Information System (INIS)

1985-05-01

The Nuclear Waste Policy Act of 1982 directs the Department of Energy to ''complete a detailed study of the need for and feasibility of, and to submit to the Congress a proposal for, the construction of one or more monitored retrievable storage facilities for high level radioactive waste and spent nuclear fuel.'' The Act directs that the proposal includes site specific designs. Further, the proposal is to include, ''for the first such facility, at least three alternative sites and at least five alternative combinations of such proposed site and facility designs...'' as well as a recommendation of ''the combination among the alternatives that the Secretary deems preferable.'' An MRS Site Screening Task Force has been formed to help identify and evaluated potential MRS facility sites within a preferred region and with the application of a siting process and criteria developed by the DOE. The activities of the task force presented in this report includes: site screening (Sections 3, 4, and 5), the MRS facilities which are to be sited are described; the criteria, process and outcome of the screening process is presented; and descriptions of the candidate MRS facility sites are given, and site evaluations (Sections 6 through 9) where the rational for the site evaluations are presented, along with each evaluation and findings of the Task Force

Monitored retrievable storage facility site screening and evaluation report

Energy Technology Data Exchange (ETDEWEB)

none,

1985-05-01

The Nuclear Waste Policy Act of 1982 directs the Department of Energy to complete a detailed study of the need for and feasibility of, and to submit to the Congress a proposal for, the construction of one or more monitored retrievable storage facilities for high level radioactive waste and spent nuclear fuel.'' The Act directs that the proposal includes site specific designs. Further, the proposal is to include, for the first such facility, at least three alternative sites and at least five alternative combinations of such proposed site and facility designs...'' as well as a recommendation of the combination among the alternatives that the Secretary deems preferable.'' An MRS Site Screening Task Force has been formed to help identify and evaluated potential MRS facility sites within a preferred region and with the application of a siting process and criteria developed by the DOE. The activities of the task force presented in this report includes: site screening (Sections 3, 4, and 5), the MRS facilities which are to be sited are described; the criteria, process and outcome of the screening process is presented; and descriptions of the candidate MRS facility sites are given, and site evaluations (Sections 6 through 9) where the rational for the site evaluations are presented, along with each evaluation and findings of the Task Force.

Evaluation of radiographers’ mammography screen-reading accuracy in Australia

International Nuclear Information System (INIS)

Debono, Josephine C; Poulos, Ann E; Houssami, Nehmat; Turner, Robin M; Boyages, John

2015-01-01

This study aimed to evaluate the accuracy of radiographers’ screen-reading mammograms. Currently, radiologist workforce shortages may be compromising the BreastScreen Australia screening program goal to detect early breast cancer. The solution to a similar problem in the United Kingdom has successfully encouraged radiographers to take on the role as one of two screen-readers. Prior to consideration of this strategy in Australia, educational and experiential differences between radiographers in the United Kingdom and Australia emphasise the need for an investigation of Australian radiographers’ screen-reading accuracy. Ten radiographers employed by the Westmead Breast Cancer Institute with a range of radiographic (median = 28 years), mammographic (median = 13 years) and BreastScreen (median = 8 years) experience were recruited to blindly and independently screen-read an image test set of 500 mammograms, without formal training. The radiographers indicated the presence of an abnormality using BI-RADS®. Accuracy was determined by comparison with the gold standard of known outcomes of pathology results, interval matching and client 6-year follow-up. Individual sensitivity and specificity levels ranged between 76.0% and 92.0%, and 74.8% and 96.2% respectively. Pooled screen-reader accuracy across the radiographers estimated sensitivity as 82.2% and specificity as 89.5%. Areas under the reading operating characteristic curve ranged between 0.842 and 0.923. This sample of radiographers in an Australian setting have adequate accuracy levels when screen-reading mammograms. It is expected that with formal screen-reading training, accuracy levels will improve, and with support, radiographers have the potential to be one of the two screen-readers in the BreastScreen Australia program, contributing to timeliness and improved program outcomes

Evaluation of radiographers’ mammography screen-reading accuracy in Australia

Energy Technology Data Exchange (ETDEWEB)

Debono, Josephine C, E-mail: josephine.debono@bci.org.au [Westmead Breast Cancer Institute, Westmead, New South Wales (Australia); Poulos, Ann E [Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, Lidcombe, New South Wales (Australia); Houssami, Nehmat [Screening and Test Evaluation Program, School of Public Health (A27), Sydney Medical School, University of Sydney, Sydney, New South Wales (Australia); Turner, Robin M [School of Public Health and Community Medicine, University of New South Wales, Sydney, New South Wales (Australia); Boyages, John [Macquarie University Cancer Institute, Macquarie University Hospital, Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales (Australia); Westmead Breast Cancer Institute, Westmead, New South Wales (Australia)

2015-03-15

This study aimed to evaluate the accuracy of radiographers’ screen-reading mammograms. Currently, radiologist workforce shortages may be compromising the BreastScreen Australia screening program goal to detect early breast cancer. The solution to a similar problem in the United Kingdom has successfully encouraged radiographers to take on the role as one of two screen-readers. Prior to consideration of this strategy in Australia, educational and experiential differences between radiographers in the United Kingdom and Australia emphasise the need for an investigation of Australian radiographers’ screen-reading accuracy. Ten radiographers employed by the Westmead Breast Cancer Institute with a range of radiographic (median = 28 years), mammographic (median = 13 years) and BreastScreen (median = 8 years) experience were recruited to blindly and independently screen-read an image test set of 500 mammograms, without formal training. The radiographers indicated the presence of an abnormality using BI-RADS®. Accuracy was determined by comparison with the gold standard of known outcomes of pathology results, interval matching and client 6-year follow-up. Individual sensitivity and specificity levels ranged between 76.0% and 92.0%, and 74.8% and 96.2% respectively. Pooled screen-reader accuracy across the radiographers estimated sensitivity as 82.2% and specificity as 89.5%. Areas under the reading operating characteristic curve ranged between 0.842 and 0.923. This sample of radiographers in an Australian setting have adequate accuracy levels when screen-reading mammograms. It is expected that with formal screen-reading training, accuracy levels will improve, and with support, radiographers have the potential to be one of the two screen-readers in the BreastScreen Australia program, contributing to timeliness and improved program outcomes.

Recommendations for newborn screening for galactokinase deficiency: A systematic review and evaluation of Dutch newborn screening data.

Science.gov (United States)

Stroek, Kevin; Bouva, Marelle J; Schielen, Peter C J I; Vaz, Frédéric M; Heijboer, Annemieke C; de Jonge, Robert; Boelen, Anita; Bosch, Annet M

2018-03-21

Galactokinase (GALK) deficiency causes cataract leading to severe developmental consequences unless treated early. Because of the easy prevention and rapid reversibility of cataract with treatment, the Dutch Health Council advised to include GALK deficiency in the Dutch newborn screening program. The aim of this study is to establish the optimal screening method and cut-off value (COV) for GALK deficiency screening by performing a systematic review of the literature of screening strategies and total galactose (TGAL) values and by evaluating TGAL values in the first week of life in a cohort of screened newborns in the Netherlands. Systematic literature search strategies in OVID MEDLINE and OVID EMBASE were developed and study selection, data collection and analyses were performed by two independent investigators. A range of TGAL values measured by the Quantase Neonatal Total Galactose screening assay in a cohort of Dutch newborns in 2007 was evaluated. Eight publications were included in the systematic review. All four studies describing screening strategies used TGAL as the primary screening marker combined with galactose-1-phosphate uridyltransferase (GALT) measurement that is used for classical galactosemia screening. TGAL COVs of 2200 μmol/L, 1665 μmol/L and 1110 μmol/L blood resulted in positive predictive values (PPV) of 100%, 82% and 10% respectively. TGAL values measured in the newborn period were reported for 39 GALK deficiency patients with individual values ranging from 3963 to 8159 μmol/L blood and 2 group values with mean 8892 μmol/L blood (SD ± 5243) and 4856 μmol/L blood (SD ± 461). Dutch newborn screening data of 72,786 newborns from 2007 provided a median TGAL value of 110 μmol/L blood with a range of 30-2431 μmol/L blood. Based on TGAL values measured in GALK deficiency patients reported in the literature and TGAL measurements in the Dutch cohort by newborn screening we suggest to perform the GALK screening with

IDIOS: An innovative index for evaluating dental imaging-based osteoporosis screening indices

Energy Technology Data Exchange (ETDEWEB)

Barngkgei, Imad; Al Haffar, Iyad; Khattab, Razan [Faculty of Dentistry, Damascus University, Damascus (Syrian Arab Republic); Halboub, Esam; Almashraqi, Abeer Abdulkareem [Dept. of Maxillofacial Surgery and Diagnostic Sciences, College of Dentistry, Jazan University, Jazan (Saudi Arabia)

2016-09-15

The goal of this study was to develop a new index as an objective reference for evaluating current and newly developed indices used for osteoporosis screening based on dental images. Its name; IDIOS, stands for Index of Dental-imaging Indices of Osteoporosis Screening. A comprehensive PubMed search was conducted to retrieve studies on dental imaging-based indices for osteoporosis screening. The results of the eligible studies, along with other relevant criteria, were used to develop IDIOS, which has scores ranging from 0 (0%) to 15 (100%). The indices presented in the studies we included were then evaluated using IDIOS. The 104 studies that were included utilized 24, 4, and 9 indices derived from panoramic, periapical, and computed tomographic/cone-beam computed tomographic techniques, respectively. The IDIOS scores for these indices ranged from 0 (0%) to 11.75 (78.32%). IDIOS is a valuable reference index that facilitates the evaluation of other dental imaging-based osteoporosis screening indices. Furthermore, IDIOS can be utilized to evaluate the accuracy of newly developed indices.

IDIOS: An innovative index for evaluating dental imaging-based osteoporosis screening indices.

Science.gov (United States)

Barngkgei, Imad; Halboub, Esam; Almashraqi, Abeer Abdulkareem; Khattab, Razan; Al Haffar, Iyad

2016-09-01

The goal of this study was to develop a new index as an objective reference for evaluating current and newly developed indices used for osteoporosis screening based on dental images. Its name; IDIOS, stands for Index of Dental-imaging Indices of Osteoporosis Screening. A comprehensive PubMed search was conducted to retrieve studies on dental imaging-based indices for osteoporosis screening. The results of the eligible studies, along with other relevant criteria, were used to develop IDIOS, which has scores ranging from 0 (0%) to 15 (100%). The indices presented in the studies we included were then evaluated using IDIOS. The 104 studies that were included utilized 24, 4, and 9 indices derived from panoramic, periapical, and computed tomographic/cone-beam computed tomographic techniques, respectively. The IDIOS scores for these indices ranged from 0 (0%) to 11.75 (78.32%). IDIOS is a valuable reference index that facilitates the evaluation of other dental imaging-based osteoporosis screening indices. Furthermore, IDIOS can be utilized to evaluate the accuracy of newly developed indices.

IDIOS: An innovative index for evaluating dental imaging-based osteoporosis screening indices

International Nuclear Information System (INIS)

Barngkgei, Imad; Al Haffar, Iyad; Khattab, Razan; Halboub, Esam; Almashraqi, Abeer Abdulkareem

2016-01-01

The goal of this study was to develop a new index as an objective reference for evaluating current and newly developed indices used for osteoporosis screening based on dental images. Its name; IDIOS, stands for Index of Dental-imaging Indices of Osteoporosis Screening. A comprehensive PubMed search was conducted to retrieve studies on dental imaging-based indices for osteoporosis screening. The results of the eligible studies, along with other relevant criteria, were used to develop IDIOS, which has scores ranging from 0 (0%) to 15 (100%). The indices presented in the studies we included were then evaluated using IDIOS. The 104 studies that were included utilized 24, 4, and 9 indices derived from panoramic, periapical, and computed tomographic/cone-beam computed tomographic techniques, respectively. The IDIOS scores for these indices ranged from 0 (0%) to 11.75 (78.32%). IDIOS is a valuable reference index that facilitates the evaluation of other dental imaging-based osteoporosis screening indices. Furthermore, IDIOS can be utilized to evaluate the accuracy of newly developed indices

Comprehensive evaluation of cervical cancer screening programs: the case of Colombia

Directory of Open Access Journals (Sweden)

Raúl Murillo

2011-12-01

Full Text Available OBJECTIVE: To identify critical screening program factors for reducing cervical cancer mortality in Colombia. MATERIAL AND METHODS: Coverage, quality, and screening follow-up were evaluated in four Colombian states with different mortality rates. A case-control study (invasive cancer and healthy controls evaluating screening history was performed. RESULTS: 3-year cytology coverage was 72.7%, false negative rate 49%, positive cytology follow-up 64.2%. There was no association between screening history and invasive cancer in two states having high cytology coverage but high false negative rates. Two states revealed association between deficient screening history and invasive cancer as well as lower positive-cytology follow-up. CONCLUSIONS: Reduced number of visits between screening and treatment is more relevant when low access to health care is present. Improved quality is a priority if access to screening is available. Suitable interventions for specific scenarios and proper appraisal of new technologies are compulsory to improve cervical cancer screening. Comprehensive process-failure audits among invasive cancer cases could improve program evaluation since mortality is a late outcome.OBJETIVO: Identificar factores críticos para reducir la mortalidad por cáncer cervical en Colombia. MATERIAL Y MÉTODOS: Se evaluó cobertura, calidad y seguimiento del tamizaje en cuatro departamentos con tasas de mortalidad diferenciales. Un estudio de casos (cáncer invasor y controles (sanos evaluó historia de tamizaje. RESULTADOS: Cobertura 72,7%; falsos negativos 49%; acceso a diagnóstico-tratamiento de HSIL 64,2%. La historia de tamizaje no se asoció con cáncer invasor en dos departamentos con elevada cobertura pero elevada proporción de falsos negativos. Dos departamentos con asociación entre historia de tamizaje deficiente y cáncer invasor tuvieron cobertura aceptable pero bajo acceso a diagnóstico-tratamiento. No hubo relación entre mortalidad

Evaluation of a hybrid ion exchange-catalyst treatment technology for nitrate removal from drinking water.

Science.gov (United States)

Bergquist, Allison M; Choe, Jong Kwon; Strathmann, Timothy J; Werth, Charles J

2016-06-01

Ion exchange (IX) is the most common approach to treating nitrate-contaminated drinking water sources, but the cost of salt to make regeneration brine, as well as the cost and environmental burden of waste brine disposal, are major disadvantages. A hybrid ion exchange-catalyst treatment system, in which waste brine is catalytically treated for reuse, shows promise for reducing costs and environmental burdens of the conventional IX system. An IX model with separate treatment and regeneration cycles was developed, and ion selectivity coefficients for each cycle were separately calibrated by fitting experimental data. Of note, selectivity coefficients for the regeneration cycle required fitting the second treatment cycle after incomplete resin regeneration. The calibrated and validated model was used to simulate many cycles of treatment and regeneration using the hybrid system. Simulated waste brines and a real brine obtained from a California utility were also evaluated for catalytic nitrate treatment in a packed-bed, flow-through column with 0.5 wt%Pd-0.05 wt%In/activated carbon support (PdIn/AC). Consistent nitrate removal and no apparent catalyst deactivation were observed over 23 d (synthetic brine) and 45 d (real waste brine) of continuous-flow treatment. Ion exchange and catalyst results were used to evaluate treatment of 1 billion gallons of nitrate-contaminated source water at a 0.5 MGD water treatment plant. Switching from a conventional IX system with a two bed volume regeneration to a hybrid system with the same regeneration length and sequencing batch catalytic reactor treatment would save 76% in salt cost. The results suggest the hybrid system has the potential to address the disadvantages of a conventional IX treatment systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of ceria on the thermally durability of Pt/Rh automotive catalyst

International Nuclear Information System (INIS)

Muraki, H.; Zhang, G.

1998-01-01

Full text: The use of cerium oxide as an oxygen storage component in automotive three-way catalysts has been well established. More recently the requirement of the three-way catalysts against the increase of the severity in emission standards has focused attention on the development of more active, durable catalysts. The thermally durability of Pt/Rh catalyst can be achieved by the utilization of thermally stable ceria as well as optimization of washcoat composition and structure in order to control the extent of interaction between PGM and ceria. In the present paper, we describe the influence of newly developed washcoat components and PGM interaction with ceria on catalytic performance. First, to clear that the interaction between PGM and ceria contributes to catalytic performance, several kinds of catalysts which have the varied interactions between PGM and ceria were prepared using engineered washcoat techniques and evaluated in the model gas reactor. It was obvious that the difference in performance among them after aging derived from a diversity of interactions between Pt, Rh, and ceria. Second, for the purpose of determining the thermally durability of the developed Pt/Rh catalyst, the catalysts including the current catalyst were aged under three different temperatures and evaluated on engine dynamometer. Result of engine dynamometer evaluation revealed that significant improvement in the thermal durability can be achieved by optimizing the PGM-ceria interaction. In conclusion, we recognize that a thermal durability of a three-way catalyst can be improved by the stabilization of proper PGM-ceria interaction after aging as well as the utilization of thermally durable ceria material

An introduction to catalyst

International Nuclear Information System (INIS)

Jeon, Hak Je

1988-11-01

This book explains basic conception of catalyst such as definition, velocity of chemical reaction and velocity of catalyst reaction, absorption with absorption energy and chemical absorption, pore structure with the role of pore and measurement of pore structure, catalyst activity on solid structure, electrical property on catalyst activity, choice and design of catalyst, catalytic reaction with reaction velocity and chemical equilibrium and reaction velocity model, measurement of reaction velocity and material analysis, catalyst for mixed compound, catalyst for solid acid and catalyst for supported metal.

Final Technical Report for GO15052 Intematix: Combinatorial Synthesis and High Throughput Screening of Effective Catalysts for Chemical Hydrides

Energy Technology Data Exchange (ETDEWEB)

Melman, Jonathan [Intematix Corporation, Fremont, CA (United States)

2017-02-22

The objectives of this project are: to discover cost-effective catalysts for release of hydrogen from chemical hydrogen storage systems; and to discover cost-effective catalysts for the regeneration of spent chemical hydrogen storage materials.

Atomic Layer Deposited Catalysts for Fuel Cell Applications

DEFF Research Database (Denmark)

Johansson, Anne-Charlotte Elisabeth Birgitta

catalyst toward the methanol oxidation reaction (MOR). In the work described in this PhD dissertation, two series of Pt-Ru ALD catalysts supported on nitrogen-doped multi-walled carbon nanotubes (N-CNTs) have been evaluated toward the CO oxidation and MOR at room temperature in a three......The micro direct methanol fuel cell (µDMFC) has been proposed as a candidate to power portable applications. The device can operate at room temperature on inexpensive, energy-dense methanol fuel, and it can be easily "recharged" by fuel refilling. Microfabrication techniques could be one route......-electrode electrochemical cell. The first series was comprised of Pt-Ru ALD catalysts of various Ru compositions, between 0 and 100 at.%. For the compositions investigated, the best catalyst had a Ru composition of 29 at.%. In the second series Ru-decorated Pt catalysts of various Ru loadings, i.e., various Ru ALD cycles...

Evaluation of French version of the Vulnerability to abuse screen scale (VASS), a elder abuse screening tool.

Science.gov (United States)

Grenier, Florian; Capriz, Françoise; Lacroix-Hugues, Virginie; Paysant, François; Pradier, Christian; Franco, Alain

2016-06-01

The elder abuse is a major public health problem. In the world, almost 4 to 10% of people of more than 65 years would be abuse. The generalist practitioners report only 2% of the elder abuse. Furthermore, the evaluations of elder abuse screenings test found in the scientist literature were unsatisfactory. Evaluate the elder abuse screening capacities of the Vulnerability to abuse screen scale (VASS) in order to propose it to the doctors. VASS was translated in French. It's a quantitative and a forward-looking study whose the answers of people of more than 65 years old were analysed and compared in blind way to the answers of socials workers. 200 patients were included between March and May 2012 in the CHU of Cimiez, Nice. We found 104 patients in danger of abuse, 40 cases of abuse revealed by the socials workers, so 20% of abuses were reported by the gold standard. It means a sensibility of 90,9%, a specificity of 49,7% and a predictive value of 96,1% to a score of 1 to the test. The screening test VASS shown it useful to detect elder people in danger of abuse but a few discriminants and not adapted to patients who have cognitive pathologies. It's a screening tool usable by default, more sensitive than others tests in the scientist literature. However, these results ask the question of the useful of these tools of elder abuse screening in comparison with the education of doctors which made proofs of success in this subject.

Micelle-derived catalysts for extended Schulz-Flory

Energy Technology Data Exchange (ETDEWEB)

Abrevaya, H.

1986-01-01

The objective of this program is to develop a synthesis gas conversion catalyst with higher selectivity to liquid fuels, while maintaining catalytic activity and stability at least equivalent relative to state-of-the-art precipitated iron catalysts. During this quarter, the emphasis in the program has been the investigation of the hydrocarbon cutoff hypothesis with supported ruthenium catalysts. An alumina-supported catalyst with smaller than 20[Angstrom] ruthenium particles was tested under conditions of maximal water gas shift activity. During this test more than 90% of the water made in the Fischer-Tropsch synthesis reaction was converted to H[sub 2]. However, the extent of ruthenium metal agglomeration was not reduced. Accordingly, it was not possible to conclude whether hydrocarbon cutoff occurs with smaller than 20[Angstrom] ruthenium particles on [gamma]-alumina. A ruthenium catalyst prepared on Y-type zeolite had 20[Angstrom] or smaller ruthenium particles according to STEM examination and a 15[Angstrom] average ruthenium metal particle size according to EXAFS examination. The ruthenium metal particle size was stable during the test with this catalyst. The hydrocarbon product distribution was Anderson-Schulz-Flory with no cutoff up to a carbon number of 160. A well-dispersed titania-supported ruthenium catalyst is going to be evaluated during the next quarter in order to determine whether hydrocarbon cutoff occurs.

Predicting catalyst-support interactions between metal nanoparticles and amorphous silica supports

Science.gov (United States)

Ewing, Christopher S.; Veser, Götz; McCarthy, Joseph J.; Lambrecht, Daniel S.; Johnson, J. Karl

2016-10-01

Metal-support interactions significantly affect the stability and activity of supported catalytic nanoparticles (NPs), yet there is no simple and reliable method for estimating NP-support interactions, especially for amorphous supports. We present an approach for rapid prediction of catalyst-support interactions between Pt NPs and amorphous silica supports for NPs of various sizes and shapes. We use density functional theory calculations of 13 atom Pt clusters on model amorphous silica supports to determine linear correlations relating catalyst properties to NP-support interactions. We show that these correlations can be combined with fast discrete element method simulations to predict adhesion energy and NP net charge for NPs of larger sizes and different shapes. Furthermore, we demonstrate that this approach can be successfully transferred to Pd, Au, Ni, and Fe NPs. This approach can be used to quickly screen stability and net charge transfer and leads to a better fundamental understanding of catalyst-support interactions.

Seismic evaluation of piping systems using screening criteria

International Nuclear Information System (INIS)

Campbell, R.D.; Landers, D.F.; Minichiello, J.C.; Slagis, G.C.; Antaki, G.A.

1994-01-01

This document may be used by a qualified review team to identify potential sources of seismically induced failure in a piping system. Failure refers to the inability of a piping system to perform its expected function following an earthquake, as defined in Table 1. The screens may be used alone or with the Seismic Qualification Utility Group -- Generic Implementation Procedure (SQUG-GIP), depending on the piping system's required function, listed in Table 1. Features of a piping system which do not the screening criteria are called outliers. Outliers must either be resolved through further evaluations, or be considered a potential source of seismically induced failure. Outlier evaluations, which do not necessarily require the qualification of a complete piping system by stress analysis, may be based on one or more of the following: simple calculations of pipe spans, search of the test or experience data, vendor data, industry practice, etc

Heterogeneous electro-Fenton catalyst for 1-butylpyridinium chloride degradation.

Science.gov (United States)

Meijide, Jessica; Pazos, Marta; Sanromán, Maria Ángeles

2017-10-15

The application of the electro-Fenton process for organic compound mineralisation has been widely reported over the past years. However, operational problems related to the use of soluble iron salt as a homogeneous catalyst involve the development of novel catalysts that are able to operate in a wide pH range. For this purpose, polyvinyl alcohol-alginate beads, containing goethite as iron, were synthesised and evaluated as heterogeneous electro-Fenton catalyst for 1-butylpyridinium chloride mineralisation. The influence of catalyst dosage and pH solution on ionic liquid degradation was analysed, achieving almost total oxidation after 60 min under optimal conditions (2 g/L catalyst concentration and pH 3). The results showed good catalyst stability and reusability, although its effectiveness decreases slightly after three successive cycles. Furthermore, a plausible mineralisation pathway was proposed based on the oxidation byproducts determined by chromatographic techniques. Finally, the Microtox® test revealed notable detoxification after treatment which demonstrates high catalyst ability for pyridinium-based ionic liquid degradation by the electro-Fenton process.

Hydrogen production via reforming of biogas over nanostructured Ni/Y catalyst: Effect of ultrasound irradiation and Ni-content on catalyst properties and performance

Energy Technology Data Exchange (ETDEWEB)

Sharifi, Mahdi [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Haghighi, Mohammad, E-mail: haghighi@sut.ac.ir [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Abdollahifar, Mozaffar [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of)

2014-12-15

Highlights: • Synthesis of nanostructured Ni/Y catalyst by sonochemical and impregnation methods. • Enhancement of size distribution and active phase dispersion by employing sonochemical method. • Evaluation of biogas reforming over Ni/Y catalyst with different Ni-loadings. • Preparation of highly active and stable catalyst with low Ni content for biogas reforming. • Getting H{sub 2}/CO very close to equilibrium ratio by employing sonochemical method. - Abstract: The effect of ultrasound irradiation and various Ni-loadings on dispersion of active phase over zeolite Y were evaluated in biogas reforming for hydrogen production. X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray, Brunauer–Emmett–Teller, Fourier transform infrared analysis and TEM analysis were employed to observe the characteristics of nanostructured catalysts. The characterizations implied that utilization of ultrasound irradiation enhanced catalyst physicochemical properties including high dispersion of Ni on support, smallest particles size and high catalyst surface area. The reforming reactions were carried out at GHSV = 24 l/g.h, P = 1 atm, CH{sub 4}/CO{sub 2} = 1 and temperature range of 550–850 °C. Activity test displayed that ultrasound irradiated Ni(5 wt.%)/Y had the best performance and the activity remained stable during 600 min. Furthermore, the proposed reaction mechanism showed that there are three major reaction channels in biogas reforming.

Impeded solid state reactions and transformations in ceramic catalysts supports and catalysts

Directory of Open Access Journals (Sweden)

Ernő E. Kiss

2012-12-01

Full Text Available Impeded chemical reactions and impeded polymorphous transformation in materials are discussed, as desired effects, for stabilization of ceramic catalyst supports and ceramic based catalysts. This paper gives a short overview about the possibilities of slowing down the aging processes in ceramic catalyst supports and catalysts. Special attention is given to alumina and titania based catalysts.

Catalyst dispersion and activity under conditions of temperature-staged liquefaction. Final report

Energy Technology Data Exchange (ETDEWEB)

Davis, A.; Schobert, H.H.; Mitchell, G.D.; Artok, L.

1993-02-01

This research program involves the investigation of the use of highly dispersed catalyst precursors for the pretreatment of coals by mild hydrogenation. During the course of this effort solvent preswelling of the coal was evaluated as a means of deeply impregnating catalysts into coal, active phases of catalysts under reaction conditions were studied and the impact of these techniques were evaluated during pretreatment and temperature-staged liquefaction. Two coals, a Texas subbituminous and a Utah high volatile A bituminous, were used to examine the effects of solvent swelling pretreatment and catalyst impregnation on conversion behavior at 275{degrees}C, representative of the first, low-temperature stage in a temperature-staged liquefaction reaction. Ferrous sulfate, iron pentacarbonyl, ammonium tetrathiomolybdate, and molybdenum hexacarbonyl were used as catalyst precursors. Without swelling pretreatment, impregnation of both coals increased conversion, mainly through increased yields of preasphaltenes.

Electron beam application for regeneration of catalysts used in refinery cracking units

International Nuclear Information System (INIS)

Kondo, Fernando Mantovani; Duarte, Celina Lopes; Sato, Ivone Mulako; Salvador, Vera Lucia Ribeiro; Calvo, Wilson Aparecido Parejo

2013-01-01

A catalyst is a substance that alters the rate of a reaction. The process of catalysis is essential to the modern day manufacturing industry, mainly in Fluid Catalytic Cracking Process (FCC) units. However, long-term exploitation of oil and gas processing catalysts leads to formation of carbon-and sulfur-containing structures of coke and dense products on the catalyst surface. They block reactive catalyst sites and reduce the catalytic activity. The main advantage of radiation processing by electron beam (EB) and gamma rays is chain cracking reaction in crude oil. Otherwise, under exposure to ionic radiation, considerable structure modification of equilibrium silica-alumina catalyst from FCC process may occur, in addition to the removal of impurities. The conditions applied in the irradiation range (20-150 kGy) of gamma rays and electron beam were not sufficient to alter the structure of the catalyst, whether for removal of the contaminant nickel, a major contaminant of the FCC catalyst, either to rupture of the crystalline structure either for the future reutilization of chemical elements. Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Energy Dispersive X-Ray Fluorescence Spectrometry (EDXRFS) analysis were used to characterize and evaluate effects of radiation processing on equilibrium catalysts purification. To evaluate and comprehend the reactive catalyst sites, Scanning Electron Microscopy (SEM) and particle size distribution analyses were carried out. (author)

Catalyst performance in magnetic esterification methyl soy oil

International Nuclear Information System (INIS)

Araujo, N.O.; Pereira, K R. de O.; Barros, A.B. de S.; Moura, T.F.B. de; Vilar, E.; Dantas, J.; Costa, A.C.F. de M.

2016-01-01

Growing concerns about the environment have encouraged the search for new fuels, including biodiesel, obtained from lipid sources that react with alcohol and catalyst. This aimed of this study to synthesize type catalyst (Ni-Zn)Fe_2O_4 and evaluate it in soy oil esterification. The catalyst was synthesized by combustion reaction and characterized by XRD, FTIR and BET. The esterification was carried out at high pressure reactor at 140°C for 1 hour with molar ratio of oil:alcohol 1:15 to 1 and 3% catalyst. From the XRD it was observed the formation of inverted spinel phase. FTIR revealed the presence of the vibrational bands 586, 1381, 1628, 2352, 2922, 3147 and 3457cm"-"1 and surface area 48m"2g"-"1, 10nm pore diameter and type IV isotherm, suggesting mesoporous material characteristic. The results indicate biodiesel conversion of 31.9% and 27.3% when using 1% and 3% catalyst, respectively. (author)

Synthesis and essay of an Ionomer like catalyst of olefins epoxidation

International Nuclear Information System (INIS)

Boyaca Mendivelso, Alejandro; Tempesti, Ezio

1995-01-01

The purpose of the present work is the preparation of an ionomer with base in Molybdenum and to evaluate its activity like catalyst of olefins epoxidation like alternative of synthesis of catalysts of the Hawk process. A polymer is synthesized with available functional groups to stabilize the metal starting from sodium molybdate; the characterization is made by atomic absorption, spectroscopy to GO, and X.P.S. The characterization indicates that indeed it is possible to stabilize the Mo in the main polymeric. The evaluation in reaction in liquid phase allows similar conversions to those of a homogeneous catalyst. The selective epoxidation of olefins for alkyl hydroperoxides, it has acquired great importance inside the industrial processes obtaining of propylene oxide due to the recent use of the terbutilic alcohol (co-produced together with the epoxide), as preservative in gasoline free of lead. In the environment of these processes, and in particular in the Hawk process possibilities of technological innovation, in the concerning to the heterogenization of conventional catalysts, at the moment used in homogeneous phase. The present work collaborate to some tentative that look for to generate alternative of preparation of catalysts for the process Hawk, synthesizing and testing the activity of an ionomer like epoxidation catalyst, which tries to reproduce the chemical structure of the complexes organ-metallic pear to suppress the separation stages and necessary recovery facilitating its recurrent reutilization with eventual economic repercussions in the industrial process. It is described the procedure of synthesis of the ionomer, the characterization and the evaluation of the activity in reaction under diverse conditions. Of the made characterization it comes off that the heterogenization of catalysts for olefins epoxidation, according to the Hawk process, is possible by means of the preparation of polymers modified appropriately. Likewise the evaluation in

New catalysts for coal processing: Metal carbides and nitrides

Energy Technology Data Exchange (ETDEWEB)

S. Ted Oyama; David F. Cox

1999-12-03

The subject of this research project was to investigate the catalytic properties of a new class of materials, transition metal carbides and nitrides, for treatment of coal liquid and petroleum feedstocks. The main objectives were: (1) preparation of catalysts in unsupported and supported form; (2) characterization of the materials; (3) evaluation of their catalytic properties in HDS and HDN; (4) measurement of the surface properties; and (5) observation of adsorbed species. All of the objectives were substantially carried out and the results will be described in detail below. The catalysts were transition metal carbides and nitrides spanning Groups 4--6 in the Periodic Table. They were chosen for study because initial work had shown they were promising materials for hydrotreating. The basic strategy was first to prepare the materials in unsupported form to identify the most promising catalyst, and then to synthesize a supported form of the material. Already work had been carried out on the synthesis of the Group VI compounds Mo{sub 2}C, Mo{sub 2}N, and WC, and new methods were developed for the Group V compounds VC and NbC. All the catalysts were then evaluated in a hydrotreating test at realistic conditions. It was found that the most active catalyst was Mo{sub 2}C, and further investigations of the material were carried out in supported form. A new technique was employed for the study of the bulk and surface properties of the catalysts, near edge x-ray absorption spectroscopy (NEXAFS), that fingerprinted the electronic structure of the materials. Finally, two new research direction were explored. Bimetallic alloys formed between two transition metals were prepared, resulting in catalysts having even higher activity than Mo{sub 2}C. The performance of the catalysts in hydrodechloration was also investigated.

Preparation of biodiesel from soybean oil by using heterogeneous catalyst

Energy Technology Data Exchange (ETDEWEB)

Ferdous, Kaniz; Rakib Uddin, M.; Islam, M.A. [Department of Chemical Engineering and Polymer Science, Shah Jalal University of Science and Technology, Sylhet 3114 (Bangladesh); Khan, Maksudur R. [Department of Chemical Engineering and Polymer Science, Shah Jalal University of Science and Technology, Sylhet 3114 (Bangladesh); Faculty of Chemical and Natural Resources Engineering, University Malaysia Pahang, 26300 Gambang, Kuantan, Pahang (Malaysia)

2013-07-01

The predicted shortage of fossil fuels and related environmental concerns has recently attracted significant attention to search alternative fuel. Biodiesel is one of the alternatives to fossil fuel. Now-a-days, most biodiesel is produced by the transesterification of oils using methanol and a homogeneous base catalyst. The use of homogeneous catalysts is normally limited to batch mode processing followed by a catalyst separation step. The immiscible glycerol phase, which accumulates during the course of the reaction, solubilizes the homogeneous base catalyst and therefore, withdraws from the reaction medium. Moreover, other difficulties of using homogeneous base catalysts relate to their sensitivity to free fatty acid (FFA) and water and resulting saponification phenomenon. High energy consumption and costly separation of the catalyst from the reaction mixture have inspired the use of heterogeneous catalyst. The use of heterogeneous catalysts does not lead to the formation of soaps through neutralization of FFA and saponification of oil. In the present paper, biodiesel was prepared from crude (soybean) oil by transesterification reaction using heterogeneous base catalyst name calcium oxide (CaO). Various reaction parameters were optimized and the biodiesel properties were evaluated.

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

Science.gov (United States)

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.

Ni Catalysts Supported on Modified Alumina for Diesel Steam Reforming

Directory of Open Access Journals (Sweden)

Antonios Tribalis

2016-01-01

Full Text Available Nickel catalysts are the most popular for steam reforming, however, they have a number of drawbacks, such as high propensity toward coke formation and intolerance to sulfur. In an effort to improve their behavior, a series of Ni-catalysts supported on pure and La-, Ba-, (La+Ba- and Ce-doped γ-alumina has been prepared. The doped supports and the catalysts have been extensively characterized. The catalysts performance was evaluated for steam reforming of n-hexadecane pure or doped with dibenzothiophene as surrogate for sulphur-free or commercial diesel, respectively. The undoped catalyst lost its activity after 1.5 h on stream. Doping of the support with La improved the initial catalyst activity. However, this catalyst was completely deactivated after 2 h on stream. Doping with Ba or La+Ba improved the stability of the catalysts. This improvement is attributed to the increase of the dispersion of the nickel phase, the decrease of the support acidity and the increase of Ni-phase reducibility. The best catalyst of the series doped with La+Ba proved to be sulphur tolerant and stable for more than 160 h on stream. Doping of the support with Ce also improved the catalytic performance of the corresponding catalyst, but more work is needed to explain this behavior.

Evaluation of the effect of an audit and feedback reporting tool on screening participation: The Primary Care Screening Activity Report (PCSAR).

Science.gov (United States)

Jonah, Leigh; Pefoyo, Anna Kone; Lee, Alex; Hader, Joanne; Strasberg, Suzanne; Kupets, Rachel; Chiarelli, Anna M; Tinmouth, Jill

2017-03-01

Participation in cancer screening is critical to its effectiveness in reducing the burden of cancer. The Primary Care Screening Activity Report (PCSAR), an electronic report, was developed as an innovative audit and feedback tool to increase screening participation in Ontario's cancer screening programs. This study aims to assess its impact on patient screening participation. This study used a retrospective cohort design to evaluate the effectiveness of the 2014 PCSAR on screening participation in Ontario's three screening programs (breast, cervix and colorectal). The 3 cohorts comprised all participants eligible for each of the programs enrolled with a primary care physician in Ontario. Two exposures were evaluated for each cohort: enrollment with a physician who was registered to receive the PCSAR and enrollment with a registered physician who also logged into the PCSAR. Logistic regression modelling was used to assess the magnitude of the effect of PCSAR on participation, adjusting for participant and physician characteristics. Across all three screening programs, 63% of eligible physicians registered to receive the PCSAR and 38% of those registered logged-in to view it. Patients of physicians who registered were significantly more likely to participate in screening, with odds ratios ranging from 1.06 [1.04;1.09] to 1.15 [1.12;1.19]. The adjusted odds ratios associated with PCSAR log-in were 1.07 [1.03;1.12] to 1.18 [1.14;1.22] across all screening programs. Implementation of the PCSAR was associated with a small increase in screening participation. The PCSAR appears to be modestly effective in assisting primary care physicians in optimizing cancer screening participation among their patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Screening dynamic evaluation of SRS cooling water line

International Nuclear Information System (INIS)

Bezler, P.; Shteyngart, S.; Breidenbach, G.

1991-01-01

The production reactors at the Savannah River Site (SRS) have been shut down due to perceived safety concerns. A major concern is the seismic integrity of the plant. A comprehensive program is underway to assess the seismic capacity of the existing systems and components and to upgrade them to acceptable levels. The evaluation of the piping systems at the SRS is a major element of this program. Many of the piping systems at the production reactors were designed without performing dynamic analyses. Instead their design complied with good design practice for dead weight supported systems with proper accommodation of thermal expansion effects. In order to gain some insight as to the seismic capacity of piping installed in this fashion, dynamic analyses were performed for some lines. Since the piping was not seismically supported, the evaluations involved various approximations and the results are only used as a screening test of seismic adequacy. In this paper, the screening evaluations performed for the raw water inlet line are described. This line was selected for evaluation since it was considered typical of the smaller diameter piping systems at the plant. It is a dead weight supported system made up of a run of small diameter piping which extends for great distances over many dead weight supports and through wall penetrations. The results of several evaluations for the system using different approximations to represent the support system are described. 2 figs., 4 tabs

Current status for applications of hydrophobic platinum catalysts in tritium removal from nuclear effluents

International Nuclear Information System (INIS)

Vagner, Irina; Ionita, Gheorghe; Varlam, Carmen

2008-01-01

Full text: Based on the long experience of the authors, in the preparation, testing and evaluation of the performances of hydrophobic catalysts, and based on the reviewed references, this paper presents up-to-date R and D results on the preparation methods and applications of the hydrophobic catalysts, in deuterium and tritium separation. The objectives of the paper are: 1. to provide a database for selection of the most appropriate catalyst and catalytic packing for above mentioned processes; 2. to evaluate the potentiality of hydrophobic Pt-catalysts in the deuterium and tritium separation; 3. to assess and find a new procedure for preparation of a new improved hydrophobic catalyst. The merits of the hydrophobic catalysts are shown in comparison to hydrophilic catalysts. As results of the review some general conclusions about the applications of hydrophobic catalysts in environmental field are as follow: 1. the hydrophobic Pt-catalysts packed in the trickle bed reactors showed a high catalytic activity and long stability; 2. the utilization of the hydrophobic Pt-catalysts for tritium removal from liquid and gaseous effluent in nuclear field was entirely confirmed on industrial scale; 3. the extension of the utilization of the hydrophobic Pt-catalysts to other new processes, which take place in presence of liquid water or high humidity, like VOCs oxidation from wastewater or H 2 -O 2 catalytic recombination, are subject to testing

Polypropylene obtained through zeolite supported catalysts

Directory of Open Access Journals (Sweden)

Queli C. Bastos

2004-01-01

Full Text Available Propylene polymerizations were carried out with f2C(Flu(CpZrCl2 and SiMe2(Ind2ZrCl2 catalysts supported on silica, zeolite sodic mordenite (NaM and acid mordenite (HM. The polymerizations were performed at different temperatures and varying aluminium/zirconium molar ratios ([Al]/[Zr]. The effect of these reaction parameters on the catalyst activity was investigated using a proposed statistical experimental planning. In the case of f2C(Flu(CpZrCl2, SiO2 and NaM were used as support and the catalyst performance evaluated using toluene and pentane as polymerization solvent. The molecular weight, molecular weight distribution, melting point and crystallinity of the polymers were examined. The results indicate very high activities for the syndiospecific heterogeneous system. Also, the polymers obtained had superior Mw and stereoregularity.

Polypropylene obtained through zeolite supported catalysts

International Nuclear Information System (INIS)

Bastos, Queli C.; Marques, Maria de Fatima V.

2004-01-01

Propylene polymerizations were carried out with φ 2 C(Flu)(Cp)ZrCl 2 and SiMe 2 (Ind)2ZrCl 2 catalysts supported on silica, zeolite sodic mordenite (NaM) and acid mordenite (HM). The polymerizations were performed at different temperatures and varying aluminium/zirconium molar ratios ([Al]/[Zr]). The effect of these reaction parameters on the catalyst activity was investigated using a proposed statistical experimental planning. In the case of f 2 C(Flu)(Cp)ZrCl 2 , SiO 2 and NaM were used as support and the catalyst performance evaluated using toluene and pentane as polymerization solvent. The molecular weight, molecular weight distribution, melting point and crystallinity of the polymers were examined. The results indicate very high activities for the syndiospecific heterogeneous system. Also, the polymers obtained had superior Mw and stereo regularity. (author)

Evaluation of air jet erosion profiles in metal mesh supported SCR plate catalyst based on glass fiber concentrations

Science.gov (United States)

Rajath, S.; Nandakishora, Y.; Siddaraju, C.; Roy, Sukumar

2018-04-01

This paper explains the evaluation of erosion profiles in metal mesh supported SCR plate catalyst structures in which the glass fibers concentration in the catalyst material is considered as prime factor for erosion resistance and mechanical strength. The samples are prepared and tested at the specified and constant conditions like velocity as 30m/s, sand flow rate as 2g/min, average particle diameter 300 µm and all these samples were tested at different angles at impact preferably 15°,30°,45°,60°,75°,and 90° as per ASTM G76 standards. Say, if 5% glass fibers are present in catalyst material, then erosion resistance increases, but the density of glass fibers is very less because each glass fiber is approximately 20 microns in diameter and weight of individual is negligible. The composition in which 2% fiber is present has slightly higher erosion comparatively, but 3% glass fibers or more foreign inclusion like excessive binders can be eliminated that contributes much for the conversion of NOx. So 2% -3% glass fibers are preferred and optimized based on NOx conversion and erosion resistance property.

D ampersand D screening risk evaluation guidance

International Nuclear Information System (INIS)

Robers, S.K.; Golden, K.M.; Wollert, D.A.

1995-09-01

The Screening Risk Evaluation (SRE) guidance document is a set of guidelines provided for the uniform implementation of SREs performed on decontamination and decommissioning (D ampersand D) facilities. Although this method has been developed for D ampersand D facilities, it can be used for transition (EM-60) facilities as well. The SRE guidance produces screening risk scores reflecting levels of risk through the use of risk ranking indices. Five types of possible risk are calculated from the SRE: current releases, worker exposures, future releases, physical hazards, and criticality. The Current Release Index (CRI) calculates the current risk to human health and the environment, exterior to the building, from ongoing or probable releases within a one-year time period. The Worker Exposure Index (WEI) calculates the current risk to workers, occupants and visitors inside contaminated D ampersand D facilities due to contaminant exposure. The Future Release Index (FRI) calculates the hypothetical risk of future releases of contaminants, after one year, to human health and the environment. The Physical Hazards Index (PHI) calculates the risks to human health due to factors other than that of contaminants. Criticality is approached as a modifying factor to the entire SRE, due to the fact that criticality issues are strictly regulated under DOE. Screening risk results will be tabulated in matrix form, and Total Risk will be calculated (weighted equation) to produce a score on which to base early action recommendations. Other recommendations from the screening risk scores will be made based either on individual index scores or from reweighted Total Risk calculations. All recommendations based on the SRE will be made based on a combination of screening risk scores, decision drivers, and other considerations, as determined on a project-by-project basis

Highly dispersed metal catalyst

Science.gov (United States)

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.

Evaluation of a screening system for obesogenic compounds: screening of endocrine disrupting compounds and evaluation of the PPAR dependency of the effect.

Directory of Open Access Journals (Sweden)

Anna Pereira-Fernandes

Full Text Available Recently the environmental obesogen hypothesis has been formulated, proposing a role for endocrine disrupting compounds (EDCs in the development of obesity. To evaluate this hypothesis, a screening system for obesogenic compounds is urgently needed. In this study, we suggest a standardised protocol for obesogen screening based on the 3T3-L1 cell line, a well-characterised adipogenesis model, and direct fluorescent measurement using Nile red lipid staining technique. In a first phase, we characterised the assay using the acknowledged obesogens rosiglitazone and tributyltin. Based on the obtained dose-response curves for these model compounds, a lipid accumulation threshold value was calculated to ensure the biological relevance and reliability of statistically significant effects. This threshold based method was combined with the well described strictly standardized mean difference (SSMD method for classification of non-, weak- or strong obesogenic compounds. In the next step, a range of EDCs, used in personal and household care products (parabens, musks, phthalates and alkylphenol compounds, were tested to further evaluate the obesogenicity screening assay for its discriminative power and sensitivity. Additionally, the peroxisome proliferator activated receptor γ (PPARγ dependency of the positive compounds was evaluated using PPARγ activation and antagonist experiments. Our results showed the adipogenic potential of all tested parabens, several musks and phthalate compounds and bisphenol A (BPA. PPARγ activation was associated with adipogenesis for parabens, phthalates and BPA, however not required for obesogenic effects induced by Tonalide, indicating the role of other obesogenic mechanisms for this compound.

Towards Prebiotic Catalytic Amyloids Using High Throughput Screening.

Directory of Open Access Journals (Sweden)

Michael P Friedmann

Full Text Available Enzymes are capable of directing complex stereospecific transformations and of accelerating reaction rates many orders of magnitude. As even the simplest known enzymes comprise thousands of atoms, the question arises as to how such exquisite catalysts evolved. A logical predecessor would be shorter peptides, but they lack the defined structure and size that are apparently necessary for enzyme functions. However, some very short peptides are able to assemble into amyloids, thereby forming a well-defined tertiary structure called the cross-β-sheet, which bestows unique properties upon the peptides. We have hypothesized that amyloids could have been the catalytically active precursor to modern enzymes. To test this hypothesis, we designed an amyloid peptide library that could be screened for catalytic activity. Our approach, amenable to high-throughput methodologies, allowed us to find several peptides and peptide mixtures that form amyloids with esterase activity. These results indicate that amyloids, with their stability in a wide range of conditions and their potential as catalysts with low sequence specificity, would indeed be fitting precursors to modern enzymes. Furthermore, our approach can be efficiently expanded upon in library size, screening conditions, and target activity to yield novel amyloid catalysts with potential applications in aqueous-organic mixtures, at high temperature and in other extreme conditions that could be advantageous for industrial applications.

Evaluating radiographers' diagnostic accuracy in screen-reading mammograms: what constitutes a quality study?

International Nuclear Information System (INIS)

Debono, Josephine C; Poulos, Ann E

2015-01-01

The aim of this study was to first evaluate the quality of studies investigating the diagnostic accuracy of radiographers as mammogram screen-readers and then to develop an adapted tool for determining the quality of screen-reading studies. A literature search was used to identify relevant studies and a quality evaluation tool constructed by combining the criteria for quality of Whiting, Rutjes, Dinnes et al. and Brealey and Westwood. This constructed tool was then applied to the studies and subsequently adapted specifically for use in evaluating quality in studies investigating diagnostic accuracy of screen-readers. Eleven studies were identified and the constructed tool applied to evaluate quality. This evaluation resulted in the identification of quality issues with the studies such as potential for bias, applicability of results, study conduct, reporting of the study and observer characteristics. An assessment of the applicability and relevance of the tool for this area of research resulted in adaptations to the criteria and the development of a tool specifically for evaluating diagnostic accuracy in screen-reading. This tool, with further refinement and rigorous validation can make a significant contribution to promoting well-designed studies in this important area of research and practice

Multiphase catalysts for selective reduction of NOx with hydrocarbons

International Nuclear Information System (INIS)

Maisuls, S.E.

2000-01-01

catalyst with Rh was studied and the results are summarized in Chapter 6. Chapter 7 presents a comparison between the Co-Pt and Co-Rh systems. Finally, we evaluate the results of this study and general conclusions with suggestions for the design of an optimal deNOx catalyst. refs

Effect of coke and catalyst structure on oxidative regeneration of hydroprocessing catalysts

Energy Technology Data Exchange (ETDEWEB)

Furimsky, E. (CANMET, Ottawa, ON (Canada). Energy Research Laboratories)

1991-04-01

Two industrial hydroprocessing catalysts used for upgrading an atmospheric residue and a gas oil, respectively were regenerated in a fixed bed using air and 2 vol.% O{sub 2}+N{sub 2} balance mixture. The regeneration in air resulted in a significant sintering of the catalyst's material. The surface area of catalysts regenerated in 2 vol.% O{sub 2} mixture was similar to that of fresh catalysts, whereas a significant loss of surface area was observed after regeneration in air. The X-ray diffraction pattern of catalysts regenerated in 2 vol.% O{sub 2}+N{sub 2} balance mixture was also similar to that of fresh catalysts. 22 refs., 9 figs., 7 tabs.

Single Pot Selective Hydrogenation of Furfural to 2-Methylfuran Over Carbon Supported Iridium Catalysts

KAUST Repository

Date, Nandan S; Hengne, Amol Mahalingappa; Huang, Kuo-Wei; Chikate, Rajeev C.; Rode, C. V.

2018-01-01

Various iridium supported carbon catalysts were prepared and screened for direct hydrogenation of furfural (FFR) to 2-methyl furan (2-MF). Amongest these, 5% Ir/C showed excellent results with complete FFR conversion and highest selectivity of 95% to 2-MF at very low H2 pressure of 100 psig. Metallic (Iro) and oxide ( IrO2) phases of Ir catalyzed first step hydrogenation involving FFR to FAL and subsequent hydrogenation to 2-MF,respecively. This was confirmed by XPS analysis and some controlled experiments. At low temperature of 140 oC, almost equal selectivities of FAL (42%) and 2-MF (43%) were observed, while higher temperature (220oC) favored selective hydrodeoxygenation. At optimized temperature, 2-MF formed selectively while higher pressure and higher catalyst loading favored ring hydrogenation of furfural rather than side chain hydrogenation. With combination of several control experimental results and detailed catalyst characterization, a plausible reaction pathway has been proposed for selective formation of 2-MF. The selectivity to various other products in FFR hydrogenation can be manipulated by tailoring the reaction conditions over the same catalyst.

Single Pot Selective Hydrogenation of Furfural to 2-Methylfuran Over Carbon Supported Iridium Catalysts

KAUST Repository

Date, Nandan S

2018-03-20

Various iridium supported carbon catalysts were prepared and screened for direct hydrogenation of furfural (FFR) to 2-methyl furan (2-MF). Amongest these, 5% Ir/C showed excellent results with complete FFR conversion and highest selectivity of 95% to 2-MF at very low H2 pressure of 100 psig. Metallic (Iro) and oxide ( IrO2) phases of Ir catalyzed first step hydrogenation involving FFR to FAL and subsequent hydrogenation to 2-MF,respecively. This was confirmed by XPS analysis and some controlled experiments. At low temperature of 140 oC, almost equal selectivities of FAL (42%) and 2-MF (43%) were observed, while higher temperature (220oC) favored selective hydrodeoxygenation. At optimized temperature, 2-MF formed selectively while higher pressure and higher catalyst loading favored ring hydrogenation of furfural rather than side chain hydrogenation. With combination of several control experimental results and detailed catalyst characterization, a plausible reaction pathway has been proposed for selective formation of 2-MF. The selectivity to various other products in FFR hydrogenation can be manipulated by tailoring the reaction conditions over the same catalyst.

Hydroprocessing catalyst development

Energy Technology Data Exchange (ETDEWEB)

Boorman, P.M.; Kydd, R.A.; Sorensen, T.S.; Chong, K.; Lewis, J.

1992-08-01

Co-Mo and Ni-Mo hydroprocessing catalysts were examined for their activity in removal of sulfur from thiophene in model compounds, and in the cracking and hydrocracking of cumene. Three types of support materials were examined: carbon, modified carbon, and carbon covered alumina. The objective of the study was to examine the correlation between catalyst activity in the hydrodenitrogenation of model compounds, and the resistance of the catalyst to nitrogen poisoning during use in the hydroprocessing of gas oils. The use of model compound testing provided information on the individual catalytic reactions promoted by those materials. Infrared spectroscopy was used to study surface species on the catalysts and to explain many of the trends in activity observed, revealing the role of fluoride and phosphorus as a secondary promoter. Testing of the catalysts in hydrotreating of gas oils allowed comparison of model compound results with those from a real feedstock. The gas oil was also spiked with a model nitrogen compound and the results from catalytic hydrotreating of this material were compared with those from unspiked material. A key finding was that the carbon supported catalysts were the most effective in treating high-nitrogen feeds. The very favorable deactivation properties of carbon and carbon-covered alumina supported catalysts make these promising from an industrial point of view where catalyst deactivation is a limiting factor. 171 refs., 25 figs., 43 tabs.

Application of Metal Catalysts for High Selectivity of Glycerol Conversion to Alcohols

Science.gov (United States)

2010-11-01

The objective of this project is to determine the applicability of metal-based catalysts and optimize the process conditions for thermochemically producing primary alcohols. Metal catalysts were evaluated for their selectivities for producing alcohol...

Evaluation of Pt/C catalyst degradation and H2O2 formation changes under simulated PEM fuel cell condition by a rotating ring-disk electrode

International Nuclear Information System (INIS)

Ono, Kenshiro; Yasuda, Yuki; Sekizawa, Koshi; Takeuchi, Norimitsu; Yoshida, Toshihiko; Sudoh, Masao

2013-01-01

Potential cycling tests using 42.2 wt% and 19.1 wt% Pt/C catalysts were conducted by the RRDE technique to evaluate the changes in the electrochemical surface area (ECSA) and H 2 O 2 formation ability of the catalysts. As the typical operating conditions of a proton exchange membrane fuel cell (PEMFC), square wave potential cycling (0.7–0.9 V) was applied to the catalysts for 150,000 cycles in an O 2 -saturated 0.1 M HClO 4 electrolyte. During the potential cycling test, electrochemical measurements were carried out to characterize the ECSA, oxygen reduction reaction (ORR) activity and H 2 O 2 formation. After 150,000 potential cyclings, while the ECSA of the 42.2 wt% Pt/C dropped by 35%, the ECSA loss for the 19.1 wt% Pt/C was 55%. This result implies that the Pt content in the cathode catalyst affects the ECSA loss during the long-term PEMFC operation. Additionally, the H 2 O 2 formation ratio obviously increased with the potential cycling only in the case of the 19.1 wt% Pt/C. In order to verify the H 2 O 2 formation dependence on the ECSA, four types of catalysts, which included different Pt loading amounts (42.2, 28.1, 19.1 and 9.5 wt% Pt/C), were evaluated, and these results explained the relationship between the ECSA decay and H 2 O 2 formation increase in the durability tests

Intermediate Ethanol Blends Catalyst Durability Program

Energy Technology Data Exchange (ETDEWEB)

West, Brian H; Sluder, Scott; Knoll, Keith; Orban, John; Feng, Jingyu

2012-02-01

In the summer of 2007, the U.S. Department of Energy (DOE) initiated a test program to evaluate the potential impacts of intermediate ethanol blends (also known as mid-level blends) on legacy vehicles and other engines. The purpose of the test program was to develop information important to assessing the viability of using intermediate blends as a contributor to meeting national goals for the use of renewable fuels. Through a wide range of experimental activities, DOE is evaluating the effects of E15 and E20 - gasoline blended with 15% and 20% ethanol - on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials. This report provides the results of the catalyst durability study, a substantial part of the overall test program. Results from additional projects will be reported separately. The principal purpose of the catalyst durability study was to investigate the effects of adding up to 20% ethanol to gasoline on the durability of catalysts and other aspects of the emissions control systems of vehicles. Section 1 provides further information about the purpose and context of the study. Section 2 describes the experimental approach for the test program, including vehicle selection, aging and emissions test cycle, fuel selection, and data handling and analysis. Section 3 summarizes the effects of the ethanol blends on emissions and fuel economy of the test vehicles. Section 4 summarizes notable unscheduled maintenance and testing issues experienced during the program. The appendixes provide additional detail about the statistical models used in the analysis, detailed statistical analyses, and detailed vehicle specifications.

Performance Testing of Hydrodesulfurization Catalysts Using a Single-Pellet-String Reactor

NARCIS (Netherlands)

Moonen, Roel; Ras, Erik Jan; Harvey, Clare; Alles, Jeroen; Moulijn, J.A.

2017-01-01

Small-scale parallel trickle-bed reactors were used to evaluate the performance of a commercial hydrodesulfurization catalyst under industrially relevant conditions. Catalyst extrudates were loaded as a single string in reactor tubes. It is demonstrated that product sulfur levels and densities

Study of PtNi/C catalyst for direct ethanol fuel cell

International Nuclear Information System (INIS)

Moraes, L.P.R. de; Silva, E.L. da; Amico, S.C.; Malfatti, C.F.

2014-01-01

In this work, PtNi binary catalyst and pure platin catalyst were synthesized by the impregnation-reduction method, using Vulcan XC72R as support, for direct ethanol fuel cells. The composition and structure of the catalysts were analyzed by X-ray diffraction, the electrochemical behavior was evaluated by cyclic voltammetry and morphology of the catalysts was studied by high-resolution transmission electron microscopy. The results showed that the addition of Ni to Pt led to the contraction of the crystal lattice, increased the catalytic activity compared to pure Pt and initiated the electrooxidation of ethanol at lower potential. (author)

Supported catalyst systems and method of making biodiesel products using such catalysts

Science.gov (United States)

Kim, Manhoe; Yan, Shuli; Salley, Steven O.; Ng, K. Y. Simon

2015-10-20

A heterogeneous catalyst system, a method of preparing the catalyst system and a method of forming a biodiesel product via transesterification reactions using the catalyst system is disclosed. The catalyst system according to one aspect of the present disclosure represents a class of supported mixed metal oxides that include at least calcium oxide and another metal oxide deposited on a lanthanum oxide or cerium oxide support. Preferably, the catalysts include CaO--CeO.sub.2ZLa.sub.2O.sub.3 or CaO--La.sub.2O.sub.3/CeO.sub.2. Optionally, the catalyst may further include additional metal oxides, such as CaO--La.sub.2O.sub.3--GdOxZLa.sub.2O.sub.3.

Evaluation of a patient navigation program to promote colorectal cancer screening in rural Georgia, USA.

Science.gov (United States)

Honeycutt, Sally; Green, Rhonda; Ballard, Denise; Hermstad, April; Brueder, Alex; Haardörfer, Regine; Yam, Jennifer; Arriola, Kimberly J

2013-08-15

Colorectal cancer (CRC) is a leading cause of cancer death in the United States. Early detection through recommended screening has been shown to have favorable treatment outcomes, yet screening rates among the medically underserved and uninsured are low, particularly for rural and minority populations. This study evaluated the effectiveness of a patient navigation program that addresses individual and systemic barriers to CRC screening for patients at rural, federally qualified community health centers. This quasi-experimental evaluation compared low-income patients at average risk for CRC (n = 809) from 4 intervention clinics and 9 comparison clinics. We abstracted medical chart data on patient demographics, CRC history and risk factors, and CRC screening referrals and examinations. Outcomes of interest were colonoscopy referral and examination during the study period and being compliant with recommended screening guidelines at the end of the study period. We conducted multilevel logistic analyses to evaluate the program's effectiveness. Patients at intervention clinics were significantly more likely than patients at comparison clinics to undergo colonoscopy screening (35% versus 7%, odds ratio = 7.9, P screening test (43% versus 11%, odds ratio = 5.9, P Screening Program, can be an effective approach to ensure that lifesaving, preventive health screenings are provided to low-income adults in a rural setting. Copyright © 2013 American Cancer Society.

Theoretical modeling of structure and function of cathode catalyst layers in PEMFC

International Nuclear Information System (INIS)

Wang, Q.; Eikerling, M.; Song, D.; Liu, Z.

2004-01-01

'Full text:' In this work, we first investigate transport and reaction kinetics in single agglomerates of cathode catalyst layers in proton exchange fuel cells. Two types of spherical agglomerates are evaluated, which represent limiting structures that can be obtained by distinct synthetic procedures. One type consists of a mixture of carbon/catalyst particles and proton conducting perfluorosulfonated ionomer (PFSI). The other type consists of carbon/catalyst particles and water-filled pores. Performance of the former type is rationalized on the basis of the well-known Thiele-modulus. Characteristics of the latter type are studied using Nernst-Planck and Poisson equations. Aspects of current conversion, reactant and current distributions, and catalyst utilization are explored. In general, the PFSI-filled agglomerates exhibit more homogeneous distributions of reaction rates. Effectiveness factors for them are close to one. However, it was found that proton penetration depths in waterflooded agglomerates could be quite significant as well under certain conditions, resulting in unexpectedly high catalyst utilization. The effects of agglomerate radius and of boundary conditions at the agglomerate surface are studied. Moreover, using the same approach, we evaluate the performance of a flat PFSI-free catalyst layer with water-filled pore space. Compared with conventional composite catalyst layers impregnated with PFSI, the PFSI-free layer exhibits better performance and high Pt utilization for thicknesses less than 0.1 μm. The significance of these results for the optimization catalyst layers in view of operation conditions and synthesis methods is discussed. (author)

Elevance of PCDD/PCDF formation for the evaluation of POPs destruction technologies. PCB destruction over a TiO2-based V2O5-WO3 catalyst

Energy Technology Data Exchange (ETDEWEB)

Weber, R. [Tuebingen Univ. (Germany)

2004-09-15

PCDDs/PCDFs and PCBs in off-gas from municipal waste incinerators. At higher temperatures, the catalyst can also be used for POPs (and VOC) destruction. In this respect Hagenmaier investigated different oxidation catalysts for PCB destruction efficiency and found superior destruction properties for the TiO2-based V{sub 2}O{sub 5}-WO{sub 3} catalyst. PCB destruction exhibits a special challenge because they are PCDF precursors and n easily be oxidised into the more toxic PCDFs. Therefore, the formation of PCDDs/PCDFs during destruction of PCBs (POPs) is one important criterion for the evaluation of a PCB (POPs) destruction technology. The relevance of PCDF formation during destruction of PCBs was demonstrated e.g. for the supercritical water oxidation technology (SCWO), a technology listed in the highest rank of non-combustion technologies from the United Nations Environmental Programme (UNEP) and the United Nations Industrial Development Organization (UNIDO), where PCDFs were formed in the %-range. Therefore the present study evaluates the relevance of PCDF formation during catalytic destruction of PCBs on a TiO{sub 2}-based V{sub 2}O{sub 5}-WO{sub 3} catalyst. The study aims to give an example of how an assessment of PCDF formation as a function of operation conditions for PCB (POPs) destruction might be performed for the evaluation of a PCB (POPs) destruction technology. Further, the results demonstrate that for the catalytic oxidation over TiO{sub 2}-based V{sub 2}O{sub 5}-WO{sub 3} catalyst, the problem of PCDF formation can be overcome.

An evaluation of a health screening program for migrant women to Taiwan, China

Directory of Open Access Journals (Sweden)

Yu-Chu Huang

2016-05-01

Full Text Available Objective: We aimed to evaluate an integrated screening program for female migrants to Taiwan. Method: We performed a mixed methodological evaluation of a public health nurse (PHN-led intervention to promote an integrated screening program for female migrants to Taiwan. The clinical case yield was determined by an audit, and staff/client questionnaires were used for the evaluation. Screening comprised surveillance for four untreated chronic diseases (hypertension, diabetes mellitus, tuberculosis, and liver disease, four cancers (mouth, bowel, liver, and cervix, parasitic infection, and hyperlipidemia. Results: Three hundred and thirty-six PHNs and 4751 immigrant women – with an average age of 29.2 years, most of whom were from Vietnam (44% or mainland China (41% – took part in the programme. Two thirds of screened women had no abnormalities. Further investigation was required in 1523 women, of whom 1220 were found to have significant disease. The majority of 280 PHNs (85% found the content, processes, and waiting time to be ‘highly acceptable’ and thought the program was worthwhile and could be incorporated into standard care. Conclusions: The Taipei County Comprehensive Health Screening Programme provided an accessible, free-of-charge, and preventative intervention for female migrants to Taiwan and had a good clinical case yield.

H3PO4/Al2O3 catalysts: characterization and catalytic evaluation of oleic acid conversion to biofuels and biolubricant

Directory of Open Access Journals (Sweden)

Lucia Regina Raddi de Araujo

2006-06-01

Full Text Available Al2O3 and H3PO4/Al2O3 catalysts were investigated in the conversion of oleic acid to biofuels and biolubricant at 1 atm and at 623 K. The catalytic tests were performed in a fixed bed and continuous flow reactor, using an oleic acid-catalyst ratio of 4 and N2 as the carrier gas. The reaction products were analyzed by gas chromatography and acidity measurements. N2 adsorption-desorption, X ray diffraction, 31P nuclear magnetic resonance and FT-IR spectroscopy were also employed to evaluate the textural, structural and acidic properties of the catalysts. The results showed that phosphoric acid impregnation improved the alumina decarboxylation activities, generating hydrocarbons in the range of gasoline, diesel oil and lubricant oil. The best catalytic performance was achieved with the highest surface area alumina impregnated with H3PO4, which was the solid that allied high total acidity with a large quantity of mesopores.

Dispersed catalysts for co-processing and coal liquefaction

Energy Technology Data Exchange (ETDEWEB)

Bockrath, B.; Parfitt, D.; Miller, R. [Pittsburgh Energy Technology Center, PA (United States)

1995-12-31

The basic goal is to improve dispersed catalysts employed in the production of clean fuels from low value hydrocarbons. The immediate objective is to determine how the properties of the catalysts may be altered to match the demands placed on them by the properties of the feedstock, the qualities of the desired end products, and the economic constraints put upon the process. Several interrelated areas of the application of dispersed catalysts to co-processing and coal conversion are under investigation. The first involves control of the selectivity of MoS{sub 2} catalysts for HDN, HDS, and hydrogenation of aromatics. A second area of research is the development and use of methods to evaluate dispersed catalysts by means of activity and selectivity tests. A micro-flow reactor has been developed for determining intrinsic reactivities using model compounds, and will be used to compare catalysts prepared in different ways. Micro-autoclaves will also be used to develop data in batch experiments at higher partial pressures of hydrogen. The third area under investigation concerns hydrogen spillover reactions between MoS{sub 2} catalysts and carbonaceous supports. Preliminary results obtained by monitoring H{sub 2}/D{sub 2} exchange reactions with a pulse-flow microreactor indicate the presence of spillover between MoS{sub 2} and a graphitic carbon. A more complete study will be made at a later stage of the project. Accomplishments and conclusions are discussed.

An evaluation of systematic tuberculosis screening at private facilities in Karachi, Pakistan.

Directory of Open Access Journals (Sweden)

Jacob Creswell

Full Text Available BACKGROUND: In Pakistan, like many Asian countries, a large proportion of healthcare is provided through the private sector. We evaluated a systematic screening strategy to identify people with tuberculosis in private facilities in Karachi and assessed the approaches' ability to diagnose patients earlier in their disease progression. METHODS AND FINDINGS: Lay workers at 89 private clinics and a large hospital outpatient department screened all attendees for tuberculosis using a mobile phone-based questionnaire during one year. The number needed to screen to detect a case of tuberculosis was calculated. To evaluate early diagnosis, we tested for differences in cough duration and smear grading by screening facility. 529,447 people were screened, 1,010 smear-positive tuberculosis cases were detected and 942 (93.3% started treatment, representing 58.7% of all smear-positive cases notified in the intervention area. The number needed to screen to detect a smear-positive case was 124 (prevalence 806/100,000 at the hospital and 763 (prevalence 131/100,000 at the clinics; however, ten times the number of individuals were screened in clinics. People with smear-positive TB detected at the hospital were less likely to report cough lasting 2-3 weeks (RR 0.66 95%CI [0.49-0.90] and more likely to report cough duration >3 weeks (RR 1.10 95%CI [1.03-1.18]. Smear-positive cases at the clinics were less likely to have a +3 grade (RR 0.76 95%CI [0.63-0.92] and more likely to have +1 smear grade (RR 1.24 95%CI [1.02-1.51]. CONCLUSIONS: Tuberculosis screening at private facilities is acceptable and can yield large numbers of previously undiagnosed cases. Screening at general practitioner clinics may find cases earlier than at hospitals although more people must be screened to identify a case of tuberculosis. Limitations include lack of culture testing, therefore underestimating true TB prevalence. Using more sensitive and specific screening and diagnostic tests such

An evaluation of systematic tuberculosis screening at private facilities in Karachi, Pakistan.

Science.gov (United States)

Creswell, Jacob; Khowaja, Saira; Codlin, Andrew; Hashmi, Rabia; Rasheed, Erum; Khan, Mubashir; Durab, Irfan; Mergenthaler, Christina; Hussain, Owais; Khan, Faisal; Khan, Aamir J

2014-01-01

In Pakistan, like many Asian countries, a large proportion of healthcare is provided through the private sector. We evaluated a systematic screening strategy to identify people with tuberculosis in private facilities in Karachi and assessed the approaches' ability to diagnose patients earlier in their disease progression. Lay workers at 89 private clinics and a large hospital outpatient department screened all attendees for tuberculosis using a mobile phone-based questionnaire during one year. The number needed to screen to detect a case of tuberculosis was calculated. To evaluate early diagnosis, we tested for differences in cough duration and smear grading by screening facility. 529,447 people were screened, 1,010 smear-positive tuberculosis cases were detected and 942 (93.3%) started treatment, representing 58.7% of all smear-positive cases notified in the intervention area. The number needed to screen to detect a smear-positive case was 124 (prevalence 806/100,000) at the hospital and 763 (prevalence 131/100,000) at the clinics; however, ten times the number of individuals were screened in clinics. People with smear-positive TB detected at the hospital were less likely to report cough lasting 2-3 weeks (RR 0.66 95%CI [0.49-0.90]) and more likely to report cough duration >3 weeks (RR 1.10 95%CI [1.03-1.18]). Smear-positive cases at the clinics were less likely to have a +3 grade (RR 0.76 95%CI [0.63-0.92]) and more likely to have +1 smear grade (RR 1.24 95%CI [1.02-1.51]). Tuberculosis screening at private facilities is acceptable and can yield large numbers of previously undiagnosed cases. Screening at general practitioner clinics may find cases earlier than at hospitals although more people must be screened to identify a case of tuberculosis. Limitations include lack of culture testing, therefore underestimating true TB prevalence. Using more sensitive and specific screening and diagnostic tests such as chest x-ray and Xpert MTB/RIF may improve results.

Follow-up Evaluation of Air Force Blood Donors Screening Positive for Chagas Disease

Science.gov (United States)

2017-08-27

Blood Donors Screening Positive for Cbagas Disease presented at/published to Military Health System Research Symposium (Florida, 27-30 Aug 2017) in...disease upon blood donation at JBSA -Lackland 6. TITLE OF MATERIAL TO BE PUBLISHED OR PRESENTED: Follow-up evaluation of Air Force blood donors ...Designated Exempt Reviewer Follow-up evaluation of Air Force blood donors screening positive for Chagas disease Joseph Marcus1, Bryant Webber2, Leo Cropper2

Electrocatalytic properties of graphite nanofibers-supported platinum catalysts for direct methanol fuel cells.

Science.gov (United States)

Park, Soo-Jin; Park, Jeong-Min; Seo, Min-Kang

2009-09-01

Graphite nanofibers (GNFs) treated at various temperatures were used as carbon supports to improve the efficiency of PtRu catalysts. The electrochemical properties of the PtRu/GNFs catalysts were then investigated to evaluate their potential for application in DMFCs. The results indicated that the particle size and dispersibility of PtRu in the catalysts were changed by heat treatment, and the electrochemical activity of the catalysts was improved. Consequently, it was found that heat treatments could have an influence on the surface and structural properties of GNFs, resulting in enhancing an electrocatalytic activity of the catalysts for DMFCs.

Evaluation of nickel and copper catalysts in biogas reforming for hydrogen production in SOFC

Energy Technology Data Exchange (ETDEWEB)

Silva, Leonardo Alves; Martins, Andre Rosa; Rangel, Maria do Carmo, E-mail: mcarmov@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Grupo de Estudos em Cinetica e Catalise; Ballarini, Adriana; Maina, Silvia [Instituto de Investigaciones en Catalisis Y Petroquimica Ing. Jose Miguel Parera (INCAPE), Santa Fe (Argentina)

2017-01-15

The solid oxide fuel cells (SOFC) enable the efficient generation of clean energy, fitting the current requirements of the growing demand for electricity and for the environment preservation. When powered with biogas (from digesters of municipal wastes), the SOFCs also contribute to reduce the environmental impact of these wastes. The most suitable route to produce hydrogen inside SOFC from biogas is through dry reforming but the catalyst is easily deactivated by coke, because of the high amounts of carbon in the stream. A promising way to overcome this drawback is by adding a second metal to nickel-based catalysts. Aiming to obtain active, selective and stable catalysts for biogas dry reforming, solids based on nickel (15%) and copper (5%) supported on aluminum and magnesium oxide were studied in this work. Samples were prepared by impregnating the support with nickel and copper nitrate, followed by calcination at 500, 600 and 800 deg C. It was noted that all solids were made of nickel oxide, nickel aluminate and magnesium aluminate but no copper compound was found. The specific surface areas did not changed with calcination temperature but the nickel oxide average particles size increased. The solids reducibility decreased with increasing temperature. All catalysts were active in methane dry reforming, leading to similar conversions but different selectivities to hydrogen and different activities in water gas shift reaction (WGSR). This behavior was assigned to different interactions between nickel and copper, at different calcination temperatures. All catalysts were active in WGSR, decreasing the hydrogen to carbon monoxide molar ratio and producing water. The catalyst calcined at 500 deg C was the most promising one, leading to the highest hydrogen yield, besides the advantage of being produced at the lowest calcination temperature, requiring less energy in its preparation. (author)

Evaluation of nickel and copper catalysts in biogas reforming for hydrogen production in SOFC

International Nuclear Information System (INIS)

Silva, Leonardo Alves; Martins, Andre Rosa; Rangel, Maria do Carmo

2017-01-01

The solid oxide fuel cells (SOFC) enable the efficient generation of clean energy, fitting the current requirements of the growing demand for electricity and for the environment preservation. When powered with biogas (from digesters of municipal wastes), the SOFCs also contribute to reduce the environmental impact of these wastes. The most suitable route to produce hydrogen inside SOFC from biogas is through dry reforming but the catalyst is easily deactivated by coke, because of the high amounts of carbon in the stream. A promising way to overcome this drawback is by adding a second metal to nickel-based catalysts. Aiming to obtain active, selective and stable catalysts for biogas dry reforming, solids based on nickel (15%) and copper (5%) supported on aluminum and magnesium oxide were studied in this work. Samples were prepared by impregnating the support with nickel and copper nitrate, followed by calcination at 500, 600 and 800 deg C. It was noted that all solids were made of nickel oxide, nickel aluminate and magnesium aluminate but no copper compound was found. The specific surface areas did not changed with calcination temperature but the nickel oxide average particles size increased. The solids reducibility decreased with increasing temperature. All catalysts were active in methane dry reforming, leading to similar conversions but different selectivities to hydrogen and different activities in water gas shift reaction (WGSR). This behavior was assigned to different interactions between nickel and copper, at different calcination temperatures. All catalysts were active in WGSR, decreasing the hydrogen to carbon monoxide molar ratio and producing water. The catalyst calcined at 500 deg C was the most promising one, leading to the highest hydrogen yield, besides the advantage of being produced at the lowest calcination temperature, requiring less energy in its preparation. (author)

Thermal and electrochemical stability of tungsten carbide catalyst supports

Energy Technology Data Exchange (ETDEWEB)

Chhina, H. [Ballard Power Systems, 9000 Glenlyon Parkway, Burnaby, BC (Canada); Department of Materials Engineering, University of British Columbia, Vancouver, BC (Canada); Campbell, S. [Ballard Power Systems, 9000 Glenlyon Parkway, Burnaby, BC (Canada); Kesler, O. [Department of Mechanical Engineering, University of British Columbia, Vancouver, BC (Canada)

2007-02-10

The thermal and electrochemical stability of tungsten carbide (WC), with and without a catalyst dispersed on it, have been investigated to evaluate the potential suitability of the material as an oxidation-resistant catalyst support. Standard techniques currently used to disperse Pt on carbon could not be used to disperse Pt on WC, so an alternative method was developed and used to disperse Pt on both commercially available WC and on carbon for comparison of stability. Electrochemical testing was performed by applying oxidation cycles between +0.6 V and +1.8 V to the support-catalyst material combinations and monitoring the activity of the supported catalyst over 100 oxidation cycles. Comparisons of activity change with cumulative oxidation cycles were made between C and WC supports with comparable loadings of catalyst by weight, solid volume, and powder volume. WC was found to be more thermally and electrochemically stable than currently used carbon support material Vulcan XC-72R. However, further optimization of the particle sizes and dispersion of Pt/WC catalyst/support materials and of comparison standards between new candidate materials and existing carbon-based supports are required. (author)

An assessment on preparation methods and applications of hydrophobic Pt-catalyst in nuclear and environmental field

International Nuclear Information System (INIS)

Ionita, Gh.; Stefanescu, I.; Varlam, Carmen

2001-01-01

Based on the long experience of the authors in the preparation, testing and evaluation of the performances of hydrophobic catalysts and based on the reviewed references, this paper presents up-to-date R and D activities on the preparation and application of hydrophobic catalysts for use in nuclear and environmental fields. Unlike the conventional hydrophilic catalysts, the hydrophobic catalysts repel the liquid water and allow the transport of the gaseous reactants and reaction products to and from catalytic active centers. For deuterium and tritium separation, over one hundred hydrophobic catalyst types have been prepared in different experimental conditions and by a large diversity of wet proofing methods. The influence of about twenty parameters on catalytic activity have been also studied. The purpose of this paper is: (1) to provide a database for preparation and selection of he most appropriate method for preparing an active hydrophobic catalyst, (2) to show how to use the hydrophobic catalyst and how to operate efficiently the reactor packed with hydrophobic catalyst, (3) to evaluate the performances and potentiality of hydrophobic catalysts in nuclear and environmental field, (4) evaluation of applications of hydrophobic catalysts in nuclear and environmental fields. As result, the following categories are shown: (1) the hydrophobic catalysts based on platinum and Teflon as wet-proofing proved to have the highest activity and the longest stability, (2) the utilization of hydrophobic catalyst as ordered mixed catalytic packing in the trickle bed or separated bed reactors is more efficient and has been entirely proved on industrial scale for tritium separation process, (3) the extension of the applications of hydrophobic catalysts for other processes which take place in the presence of saturated humidity or liquid water in environmental protection field. The merits of hydrophobic Pt-catalysts for tritium separation are discussed in comparison to other

Characteristics improvement of hydrophobic polytetrafluoroethylene-platinum catalysts for tritium separation

International Nuclear Information System (INIS)

Popescu, I.; Ionita, Gh.; Dobrinescu, D.; Varlam, C.; Stefanescu, I.

2006-01-01

Full text: Based on the long experience of the authors in the preparation, testing and evaluation of the performances of hydrophobic catalysts and based on the reviewed references, this paper presents up-to-date R and D activities on the preparation methods and applications of the hydrophobic catalysts in tritium separation. The objectives of the paper are: how to improve the characteristics and performance of platinum hydrophobic catalysts; to assess and find a new procedure for the preparation of a new improved hydrophobic catalyst. From reviewed references one can conclude that platinum is the most active and efficient catalytic metal while the polytetrafluoroethylene is the best wet-proofing agent. A new improved hydrophobic Pt-catalyst has been proposed and its testing is now underway. The main steps and experimental conditions of preparation are thoroughly discussed. A new wet-proofing agent and new binders (titanium dioxide, cerium dioxide, zirconium dioxide) with a catalytic role are proposed and tested. The physico-structural parameters of the improved catalyst have been determined and are discussed in detail. The new proposal is a promising idea to improve the performance of conventional hydrophobic Pt-catalysts. (authors)

The comparative evaluation of film-screen combinations

International Nuclear Information System (INIS)

Choi, Gyung Ja; Choi, Syng Kyu

1988-01-01

This study was to compare the quality of image by different screen and film combinations. Using the sensitometer measured the speed and average gradient of blue sensitive films and orthochromatic films. The films was combined with rare earth screen LR, Lm, LF and conventional screen OM, OH, XOR, OKa and exposed the stepwedge to impulse 2, 3, 4, 6, 10, 15, 24, 38, 60 and measured the density. The following results were obtained: 1. The density of film and film-screen combinations showed significant difference, then in film-screen combinations was significantly different by the screens than films. 2. The speed of blue sensitive films was little different, the TMG of orthochromatic films producted high speed, and the AX films was high average gradient. 3. The relative speed of film-screen combinations showed significant difference, and was high in the OKa of the conventional screens and in the LR of the rare earth screens, especially that of LR screen in the combination with blue sensitive films was high. 4. The average gradient of film-screen combinations showed no significant difference, and was high in the OKa screen and LR/OG combination, and that of OKa/AX combination was highest. 5. The latitude of film-screen combinations showed significant difference by screens, and was high in the LM screen in combination with blue sensitive films and in the OM screen in combination with orthochromatic films. 6. The subject contrast of film-screen combinations showed significant difference by screen, and was high in the LR screen in combination with blue sensitive AX film and orthochromatic TMG film.

evaluation of commercial FCC catalysts for hydrocarbon conversion. I. Physicochemical characterization and n-hexane conversion.

NARCIS (Netherlands)

Brait, A.; Brait, A.; Seshan, Kulathuiyer; Lercher, J.A.

1998-01-01

The physicochemical properties of six steam-stabilized, commercial FCC catalysts were compared in respect of their catalytic activity for n-hexane conversion. The conversion of n-hexane over these catalysts could be fully explained by three reaction pathways: protolytic cracking, protolytic

Development of Molecular Catalysts to Bridge the Gap between Heterogeneous and Homogeneous Catalysts

Science.gov (United States)

Ye, Rong

Catalysts, heterogeneous, homogeneous, and enzymatic, are comprised of nanometer-sized inorganic and/or organic components. They share molecular factors including charge, coordination, interatomic distance, bonding, and orientation of catalytically active atoms. By controlling the governing catalytic components and molecular factors, catalytic processes of a multichannel and multiproduct nature could be run in all three catalytic platforms to create unique end-products. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis. Recyclable catalysts, especially those that display selective reactivity, are vital for the development of sustainable chemical processes. Among available catalyst platforms, heterogeneous catalysts are particularly well-disposed toward separation from the reaction mixture via filtration methods, which renders them readily recyclable. Furthermore, heterogeneous catalysts offer numerous handles - some without homogeneous analogues - for performance and selectivity optimization. These handles include nanoparticle size, pore profile of porous supports, surface ligands and interface with oxide supports, and flow rate through a solid catalyst bed. Despite these available handles, however, conventional heterogeneous catalysts are themselves often structurally heterogeneous compared to homogeneous catalysts, which complicates efforts to optimize and expand the scope of their reactivity and selectivity. Ongoing efforts are aimed to address the above challenge by heterogenizing homogeneous catalysts, which can be defined as the modification of homogeneous catalysts to render them in a separable (solid) phase from the starting materials and products. Specifically, we grow the small nanoclusters in dendrimers, a class of uniform polymers with the connectivity of fractal trees and generally radial symmetry. Thanks to their dense multivalency, shape persistence and structural uniformity, dendrimers have proven to

Communicating catalysts

Science.gov (United States)

Weckhuysen, Bert M.

2018-06-01

The beauty and activity of enzymes inspire chemists to tailor new and better non-biological catalysts. Now, a study reveals that the active sites within heterogeneous catalysts actively cooperate in a fashion phenomenologically similar to, but mechanistically distinct, from enzymes.

Methods of making textured catalysts

Science.gov (United States)

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.

Feasibility evaluation of using spent FCC catalyst for metals treatment from industrial waste; Avaliacao do potencial de recuperacao de niquel de catalisadores equilibrados (E-CAT) atraves da tecnica de remediacao eletrocinetica

Energy Technology Data Exchange (ETDEWEB)

Baptista, Adalberto; Ponte, Haroldo de Araujo [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil)

2004-07-01

The purpose of this work is to describe the feasibility evaluation using FCC catalyst for treatment from industrial wastes increasing the life time of the spent catalysts and reducing the environmental impact. Evaluated the reutilization of catalyst in process recovery of nickel adsorbed. The technique used was the Electrokinetic Remediation. This technique is based in application of a direct current of low intensity or low potential between the electrodes located in soil. The pollutants are mobilized how loaded species or particles. It used a electrokinetic reactor with approximated volume of 1200 cm{sup 3}, where the residue is placed. In your extremity are adapted two cameras of acrylic, being one anodic, with steel inox 304 electrode, and other cathodic, with lead electrode. In anodic camera, it was injected, with aid a bomb, a solution of sulfuric acid, which work as electrolyte, to a flow rate of 20 ml/h. Was evaluated the desorption of Nickel in the equilibrium catalyst submitting a variation of the conditions of the concentration and potential. (author)

Hydrotreatment of heavy oil from coal liquefaction on Sulfide Ni - W Catalysts

International Nuclear Information System (INIS)

Zhi-ping Lei; Li-juan Gao; Heng-fu Shui; Shi-biao, Ren; Zhi-cai Wang; Kang-shi Gang

2011-01-01

Heavy oil (distillation temperature: 320-340 deg C) derived from the direct coal liquefaction process using Shengli coal were hydrotreated using sulfided Ni-Mo/Al 2 O 3 , Ni-W/Al 2 O 3 , and Ni-W/SiO 2 catalysts respectively. The sulfided catalysts were characterized by BET, XRD, H 2 -TPR and NH 3 -TPD respectively. The evaluations of the hydrodenitrogenation (HDN) and hydrodearomatization (HDA) properties of heavy oil on the three catalysts were carried out at 400 deg C and 5.0 MPa initial H2 pressure. The W-based catalysts displayed better performances than Mo-based catalysts for the HDN and HDA reactions. Al 2 O 3 supported catalysts were found to have higher catalytic activities than on SiO 2 supported ones. The activities of sulfided catalysts were associated mainly with the nature of active sites, acidity, metal sulfide crystallite size and the amount of the reducible sulfur species of metal sulfide. (author)

Energetics of Elementary Steps in Catalysis and Their Use to Search for New Catalysts

Science.gov (United States)

Wolcott, Christopher A.

) is a fairly new technique which allows one to probe the heats of formation of such adsorbates for the first time. In this thesis SCAC is used to study the dissociative adsorption of diiodomethane on Pt(111) to produce adsorbed -CH2 and -CH, and water on Fe 3O4(111) and NiO(111) to produce adsorbed -OH. This work expands the library of adsorbates on transition metal surfaces which has been studied by SCAC, and is among the first ever measurements of molecules on well-defined oxide surfaces using SCAC. These results are compared to density functional theory (DFT) calculations of adsorbate energetics, and their use as computational benchmarks is discussed. A new, universally-applicable method of data analysis for SCAC is also developed which allows for the extraction of heat data even in the presence of complex surface reaction/diffusion dynamics without any need for kinetic modeling as required in previous analysis methods, thus greatly expanding the versatility of SCAC. Finally a new method of computational catalyst screening is presented which uses the concept of degree of rate control to simplify calculations compared to the standard method developed by Jens Norskov's group. It greatly reduces the number of adsorbate energies needed to predict the reaction rate for a new catalyst, and provides greater accuracy when studying materials with similar properties to the reference catalyst used. The Norskov method is more robust when extended to materials that are dissimilar. The new method presented here is thus expected to be an important complimentary tool to Norskov's method for high-throughput computational screening. Taken together, the results presented in this dissertation show the importance of experimental measurements for guiding the development of fast quantum mechanical methods like DFT to more closely approach thru "chemical accuracy" in energetic prediction, and how one could use "chemically accurate" DFT energies to rapidly screen potential catalysts for

In-situ hydrodeoxygenation of phenol by supported Ni catalyst-explanation for catalyst performance

DEFF Research Database (Denmark)

Wang, Ze; Zeng, Ying; Lin, Weigang

2017-01-01

In-situ hydrodeoxygenation of phenol with aqueous hydrogen donor over supported Ni catalyst was investigated. The supported Ni catalysts exerted very poor performance, if formic acid was used as the hydrogen donor. Catalyst modification by loading K, Na, Mg or La salt could not make the catalyst...... performance improved. If gaseous hydrogen was used as the hydrogen source the activity of Ni/Al2O3 was pretty high. CO2 was found poisonous to the catalysis, due to the competitive adoption of phenol with CO2. If formic acid was replaced by methanol, the catalyst performance improved remarkably, with major...... products of cyclohexanone and cyclohexanol. The better effect of methanol enlightened the application of the supported Ni catalyst in in-situ hydrodeoxygenation of phenol....

Synthetic production of fuels by the Fischer Tropsch reaction using iron catalysts

International Nuclear Information System (INIS)

Rodriguez Cepeda, Rodrigo; Pacheco Ochoa, Luis

2004-01-01

A series of iron catalysts were prepared on three different types of supports: alumina and two activated carbons from eucalyptus woods and tagua seeds. Potassium was used as promoter and palladium was deposited by the excess wetness impregnation method. The catalysts were characterized by N 2 adsorption at 77 K, XRD and TPR analysis and evaluated as Fischer-Tropsch catalysts. The carbon supported catalysts favour the production of liquid hydrocarbons and decrease the aqueous phase. Those supported with alumina form gases and aqueous phase as the main products. The α p parameters of the Schulz-Flory distribution show hydrocarbons between gasoline and diesel

Change in activity of catalysts for the oxidation of tritium during a fire event

International Nuclear Information System (INIS)

Iwai, Yasunori; Sato, Katsumi; Yamanishi, Toshihiko

2012-01-01

Highlights: ► We experimentally demonstrated the influence of produced gases from burned low-halogen cable on the activity of catalysts for tritium oxidation. ► At 423 K, no considerable decrease in catalytic activity was observed. ► At 293 K, considerable increase in catalytic activity was initially observed due to the effect of produced hydrogen. Then the temporary decrease was observed due mainly to the effect of produced moisture, however the activity was gradually recovered. - Abstract: The catalytic performance should be maintained in any off normal events. Fire accident is the typical off normal event. In the fusion plant, typical combustibles are evaluated to be polymeric low-halogen cables. Produced gases from burned low-halogen cable may affect the activity of catalysts for the oxidation of tritium. We experimentally demonstrated the influence of produced gases from burned low-halogen cable on the activity of catalyst using tritium gas. Our evaluation showed that ethylene, methane and benzene were major produced gases. The activity of catalysts for the oxidation of tritium during a fire event was evaluated using a commercial hydrophilic Pt/Al 2 O 3 catalyst and a commercial hydrophobic Pt-catalyst. The temperature of catalytic reactor was selected to be 423 and 293 K. At 423 K, no considerable decrease in catalytic activity was observed for both catalysts even in the presence of produced gases from burned low-halogen cable. At 293 K, considerable increase in catalytic activity was initially observed for both catalysts due to the effect of produced hydrogen. Then the temporary decrease was observed, however the catalytic activity was gradually recovered to be the original activity. Consequently, the irreversible decrease in activity of the catalysts during a fire event was not observed.

Catalyst development and systems analysis of methanol partial oxidation for the fuel processor - fuel cell integration

Energy Technology Data Exchange (ETDEWEB)

Newson, E; Mizsey, P; Hottinger, P; Truong, T B; Roth, F von; Schucan, Th H [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

Methanol partial oxidation (pox) to produce hydrogen for mobile fuel cell applications has proved initially more successful than hydrocarbon pox. Recent results of catalyst screening and kinetic studies with methanol show that hydrogen production rates have reached 7000 litres/hour/(litre reactor volume) for the dry pox route and 12,000 litres/hour/(litre reactor volume) for wet pox. These rates are equivalent to 21 and 35 kW{sub th}/(litre reactor volume) respectively. The reaction engineering problems remain to be solved for dry pox due to the significant exotherm of the reaction (hot spots of 100-200{sup o}C), but wet pox is essentially isothermal in operation. Analyses of the integrated fuel processor - fuel cell systems show that two routes are available to satisfy the sensitivity of the fuel cell catalysts to carbon monoxide, i.e. a preferential oxidation reactor or a membrane separator. Targets for individual system components are evaluated for the base and best case systems for both routes to reach the combined 40% efficiency required for the integrated fuel processor - fuel cell system. (author) 2 figs., 1 tab., 3 refs.

Alloy catalyst material

DEFF Research Database (Denmark)

2014-01-01

The present invention relates to a novel alloy catalyst material for use in the synthesis of hydrogen peroxide from oxygen and hydrogen, or from oxygen and water. The present invention also relates to a cathode and an electrochemical cell comprising the novel catalyst material, and the process use...... of the novel catalyst material for synthesising hydrogen peroxide from oxygen and hydrogen, or from oxygen and water....

A Fisheries Evaluation of the Richland and Toppenish/Satus Canal Fish Screening Facilities, Spring 1986 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Neitzel, D.A.; Abernethy, C. Scott; Lusty, E. William

1987-05-01

The fisheries evaluation phase of diversion screen effectiveness summarizes the results of work at the Richland and Toppenish/Satus Fish screening facilities (Richland Screens and Toppenish/Satus Screens) during 1986. More than 10,000 steelhead, Salmo gairdneri, and chinook salmon, Oncorhynchus tshawytscha, were released at the screen diversions. At the Richland Screens, 61% of the released steelhead were recovered and 1.1% were descaled; 93% of the spring chinook salmon were recovered and less than 1% were descaled. At the Toppenish/Satus Screens, only steelhead were evaluated for descaling; 88.9% were recovered and 23.9% were descaled. Only steelhead were evaluated because the Yakima River fisheries managers did not expect any other smolts to occur in Toppenish Creek. Because of the acclimation conditions and the amount of time the fish had to be held before testing, some of the test population were descaled during holding and transportation. The 23.9% descaling for the test fish was compared to 26.4% for the controls.

Hydroisomerization of n-dodecane over Pt/Al-MCM-48 catalysts.

Science.gov (United States)

Yun, Soyoung; Park, Young-Kwon; Jeong, Soon-Yong; Han, Jeongsik; Jeon, Jong-Ki

2014-04-01

The objective of this study is to evaluate the catalytic potential of Pt/Al-MCM-48 catalysts in hydroisomerization of n-dodecane. The effects of the Si/Al ratio and platinum loading on the acid characteristics of Al-MCM-48 and the catalytic performance in n-dodecane hydroisomerization were analyzed. The catalysts were characterized by X-ray diffraction, nitrogen adsorption, infrared spectroscopy of pyridine adsorption, and temperature programmed desorption of ammonia. The number of weak strength acid sites on Al-MCM-48 increased with 0.5 wt% platinum loading. The weak strength acid sites of Pt/Al-MCM-48 catalysts were ascribed to Lewis acid sites, which can be confirmed by NH3-TPD and FTIR spectra of pyridine adsorption. Iso-dodecane can be produced with high selectivity in n-dodecane hydrosisomerization over Pt/Al-MCM-48 catalysts. This is attributed to the mild acidic properties of Pt/Al-MCM-48 catalysts.

Vibration measurements of automobile catalyst

Science.gov (United States)

Aatola, Seppo

1994-09-01

Vibration of catalyst cell, which is inside the casing of the catalyst, is difficult to measure with usual measuring instrumentation. When catalyst is in use, there is hot exhaust gas flow though the catalyst cell and temperature of the cell is approximately +900 degree(s)C. Therefore non-contact Laser- Doppler-Vibrometer was used to measure vibration velocity of the catalyst cell. The laser beam was directed towards the cell through pipe which was put through and welded to the casing of the catalyst. The outer end of the pipe was screw down with a tempered class to prevent exhaust gas flow from the pipe. The inner end of the pipe was open and few millimeters away from the measuring point. Catalyst was attached to the engine with two ways, rigidly close to the engine and flexible under the engine. The engine was running in test bench under controlled conditions. Vibration measurements were carried out during constant running speeds of the engine. Vibration signals were captured and analyzed with FFT-analyzer. Vibration of catalyst cell was strongest at running speed of 5000 rpm, from 10 to 20 g (1 g equals 9.81 ms-2), when catalyst was attached rigidly close to the engine. At running speed of 3000 rpm, vibration of catalyst cell was from 2 to 3 g in most cases, when catalyst was attached either rigidly or flexible to the engine. It is estimated that in real life, i.e. when catalyst is attached to car with same engine, vibration of catalyst cell at running speed of 5000 rpm is somewhere between 1 and 10 g. At running speed of 3000 rpm, which may be more often used when driving car (car speed approximately 100 kmh-1), vibration of catalyst cell is probably few g's.

Carbon Nanofiber Supported Transition-Metal Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

NARCIS (Netherlands)

Jongerius, A.; Gosselink, R.W.; Dijkstra, J.; Bitter, J.H.; Bruijnincx, P.C.A.; Weckhuysen, B.M.

2013-01-01

Hydrodeoxygenation (HDO) studies over carbon nanofiber-supported (CNF) W2C and Mo2C catalysts were performed on guaiacol, a prototypical substrate to evaluate the potential of a catalyst for valorization of depolymerized lignin streams. Typical reactions were executed at 55 bar hydrogen pressure

Catalyst for microelectromechanical systems microreactors

Science.gov (United States)

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.

Modified silica-based heterogeneous catalysts for etherification of glycerol

Energy Technology Data Exchange (ETDEWEB)

Gholami, Zahra, E-mail: zahra.gholami@petronas.com.my [Centralized Analytical Laboratory, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Abdullah, Ahmad Zuhairi, E-mail: chzuhairi@usm.my; Gholami, Fatemeh, E-mail: fgholami59@gmail.com [School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus,14300 Nibong Tebal, Penang (Malaysia); Vakili, Mohammadtaghi, E-mail: farshid3601@gmail.com [School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia)

2015-07-22

The advent of mesoporous silicas such as MCM-41 has provided new opportunities for research into supported metal catalysis. The loading of metals into framework structures and particularly into the pores of porous molecular sieves, has long been of interest because of their potential catalytic activity. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were characterized using BET surface analysis, SEM and TEM. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca{sub 1.6}La{sub 0.6}/MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%.

Modified silica-based heterogeneous catalysts for etherification of glycerol

International Nuclear Information System (INIS)

Gholami, Zahra; Abdullah, Ahmad Zuhairi; Gholami, Fatemeh; Vakili, Mohammadtaghi

2015-01-01

The advent of mesoporous silicas such as MCM-41 has provided new opportunities for research into supported metal catalysis. The loading of metals into framework structures and particularly into the pores of porous molecular sieves, has long been of interest because of their potential catalytic activity. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were characterized using BET surface analysis, SEM and TEM. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca 1.6 La 0.6 /MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%

Phosphorus poisoning of molybdenum sulfide hydrodesulfurization catalysts supported on carbon and alumina

NARCIS (Netherlands)

Bouwens, S.M.A.M.; Vissers, J.P.R.; Beer, de V.H.J.; Prins, R.

1988-01-01

Phosphorus-containing Mo sulfide catalysts supported on ¿-Al2O3 and activated carbon were evaluated for their thiophene HDS activities. Phosphorus was added as phosphoric acid to the carrier material prior to the molybdenum component. The thiophene HDS activity of the carbon-supported catalysts was

Regeneration of Hydrotreating and FCC Catalysts

Energy Technology Data Exchange (ETDEWEB)

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

The effect of diluting ruthenium by iron in RuxSey catalyst for oxygen reduction

International Nuclear Information System (INIS)

Delacote, Cyril; Lewera, Adam; Pisarek, Marcin; Kulesza, Pawel J.; Zelenay, Piotr; Alonso-Vante, Nicolas

2010-01-01

This study has focused on the synthesis of novel oxygen reduction reaction (ORR) chalcogenide catalysts, with Ru partially replaced by Fe in a cluster-type Ru x Se y . The catalysts were obtained by thermal decomposition of Ru 3 (CO) 12 and Fe(CO) 5 in the presence of Se. As indicated by the XPS data, the composition of catalyst nanoparticles depends on the solvent used (either p-xylene or dichlorobenzene). The presence of iron in synthesized catalysts has been confirmed by both EDAX and XPS. Voltammetric activation of the catalysts results in a partial removal of iron and unreacted selenium from the surface. The ORR performance of electrochemically pre-treated catalysts was evaluated using rotating disk and ring-disk electrodes in a sulfuric acid solution. No major change in the ORR mechanism relative to the Se/Ru catalyst has been observed with Fe-containing catalysts.

Performance of a polymer electrolyte membrane fuel cell with thin film catalyst electrodes

Energy Technology Data Exchange (ETDEWEB)

Chun, Young Gab; Kim, Chang Soo; Peck, Dong Hyun; Shin, Dong Ryul [Korea Institute of Energy Research, Taejon (Korea, Republic of)

1998-03-15

In order to develop a kW-class polymer electrolyte membrane fuel cell (PEMFC), several electrodes have been fabricated by different catalyst layer preparation procedures and evaluated based on the cell performance. Conventional carbon paper and carbon cloth electrodes were fabricated using a ptfe-bonded Pt/C electrol catalyst by coating and rolling methods. Thin-film catalyst/ionomer composite layers were also formed on the membrane by direct coating and transfer printing techniques. The performance evaluation with catalyst layer preparation methods was carried out using a large or small electrode single cell. Conventional and thin film membrane and electrode assemblies (MEAs) with small electrode area showed a performance of 350 and 650 mA/cm{sup 2} at 0.6 V, respectively. The performance of direct coated thin film catalyst layer with 300 cm{sup 2} MEAs was higher than those of the conventional and transfer printing technique MEAs. The influence of some characteristic parameters of the thin film electrode on electrochemical performance was examined. Various other aspects of overall operation of PEMFC stacks were also discussed. (orig.)

Design criteria for stable Pt/C fuel cell catalysts

Directory of Open Access Journals (Sweden)

Josef C. Meier

2014-01-01

Full Text Available Platinum and Pt alloy nanoparticles supported on carbon are the state of the art electrocatalysts in proton exchange membrane fuel cells. To develop a better understanding on how material design can influence the degradation processes on the nanoscale, three specific Pt/C catalysts with different structural characteristics were investigated in depth: a conventional Pt/Vulcan catalyst with a particle size of 3–4 nm and two Pt@HGS catalysts with different particle size, 1–2 nm and 3–4 nm. Specifically, Pt@HGS corresponds to platinum nanoparticles incorporated and confined within the pore structure of the nanostructured carbon support, i.e., hollow graphitic spheres (HGS. All three materials are characterized by the same platinum loading, so that the differences in their performance can be correlated to the structural characteristics of each material. The comparison of the activity and stability behavior of the three catalysts, as obtained from thin film rotating disk electrode measurements and identical location electron microscopy, is also extended to commercial materials and used as a basis for a discussion of general fuel cell catalyst design principles. Namely, the effects of particle size, inter-particle distance, certain support characteristics and thermal treatment on the catalyst performance and in particular the catalyst stability are evaluated. Based on our results, a set of design criteria for more stable and active Pt/C and Pt-alloy/C materials is suggested.

Symptoms and biomarkers associated with celiac disease: evaluation of a population-based screening program in adults.

Science.gov (United States)

Kårhus, Line L; Thuesen, Betina H; Rumessen, Jüri J; Linneberg, Allan

2016-11-01

To identify possible early predictors (symptoms and biomarkers) of celiac disease, compare symptoms before and after screening, and evaluate the diagnostic efficacy of serologic screening for celiac disease in an adult Danish population. This cross-sectional population-based study was based on the 5-year follow-up of the Health2006 cohort, where 2297 individuals were screened for celiac disease; 56 were antibody positive and thus invited to clinical evaluation. Eight were diagnosed with biopsy-verified celiac disease. A follow-up questionnaire was sent to antibody-positive individuals 19 months after the clinical evaluation to obtain information on their symptoms and their experience with participation in the screening. Before screening, participants subsequently diagnosed with celiac disease did not differ from the rest of the population with respect to symptoms, but had significantly lower total cholesterol. Tissue transglutaminase IgA antibodies with a cut-off of 10 U/ml had a positive predictive value of 88%. The majority of participants were satisfied with their participation in the screening program. Individuals with celiac disease were generally satisfied with having been diagnosed and 71% felt better on a gluten-free diet. There were no differences in the prevalence of symptoms between participants with and without screening-detected celiac disease, confirming that risk stratification in a general population by symptoms is difficult. The majority of participants diagnosed with celiac disease felt better on a gluten-free diet despite not reporting abdominal symptoms before diagnosis and participants in the clinical evaluation were generally satisfied with participation in the screening program.

Comparison of Alcohol Use Disorder Screens During College Athlete Pre-Participation Evaluations.

Science.gov (United States)

Majka, Erek; Graves, Travis; Diaz, Vanessa A; Player, Marty S; Dickerson, Lori M; Gavin, Jennifer K; Wessell, Andrea

2016-05-01

The US Preventive Services Task Force (USPSTF) recommends screening adults for alcohol misuse, a challenge among young adults who may not have regular primary care. The pre-participation evaluation (PPE) provides an opportunity for screening, but traditional screening tools require extra time in an already busy visit. The objective of this study was to compare the 10-item Alcohol Use Disorders Identification Test (AUDIT) with a single-question alcohol misuse screen in a population of college-aged athletes. This cross-sectional study was performed during an athletic PPE clinic at a college in the Southeastern United States among athletes ages 18 years and older. Written AUDIT and single-question screen "How many times in the past year have you had X or more drinks in a day?" (five for men, four for women) asked orally were administered to each participant. Sensitivity, specificity, and positive and negative predictive values for the single-question screen were compared to AUDIT. A total of 225 athletes were screened; 60% were female; 29% screened positive by AUDIT; 59% positive by single-question instrument. Males were more likely to screen positive by both methods. Compared to the AUDIT, the brief single-question screen had 92% sensitivity for alcohol misuse and 55% specificity. The negative predictive value of the single-question screen was 95% compared to AUDIT. A single-question screen for alcohol misuse in college-aged athletes had a high sensitivity and negative predictive value compared to the more extensive AUDIT screen. Ease of administration of this screening tool is ideal for use within the pre-participation physical among college-aged athletes who may not seek regular medical care.

Catalysts for synthetic liquid fuels

Energy Technology Data Exchange (ETDEWEB)

Bruce, L.A.; Turney, T.W.

1987-12-01

Fischer-Tropsch catalysts have been designed, characterized and tested for the selective production of hydrocarbons suitable as synthetic liquid transport fuels from synthesis gas (i.e., by the reduction of carbon monoxide with hydrogen). It was found that hydrocarbons in the middle distillate range, or suitable for conversion to that range, could be produced over several of the new catalyst systems. The various catalysts examined included: (1) synthetic cobalt clays, mainly cobalt chlorites; (2) cobalt hydrotalcites; (3) ruthenium metal supported on rare earth oxides of high surface area; and (4) a novel promoted cobalt catalyst. Active and selective catalysts have been obtained, in each category. With the exception of the clays, reproducibility of catalyst performance has been good. Catalysts in groups 2 and 4 have exhibited very high activity, with long lifetimes and easy regeneration.

[Hearing screening at nursery schools: results of an evaluation study].

Science.gov (United States)

Weichbold, Viktor; Rohrer, Monika; Winkler, Cornelia; Welzl-Müller, Kunigunde

2004-07-31

This study aimed to evaluate the hearing screening of pre-school children at nursery schools in Tyrol, Austria. 47 nursery schools with a total of 2199 enrolled children participated in the study. At the screening, the children were presented a series of tones at frequencies 0.5 kHz (25dB), 1 kHz, 2 kHz, 3 kHz, and 4 kHz (20 dB each) from portable audiometers. The tones were presented over headphones for each ear separately and at irregular intervals. Failure to respond to any of the frequencies was considered failure of the screening. Parents were then advised in written form to have the child examined by an ENT-specialist. 1832 individuals were screened (coverage: 83% of nursery school children; corresponding to at least 63% of all Tyrolean children aged 3 to 5 years). Of these, 390 failed the test (referral rate: 21% of all screened). Examination through an ENT-specialist occurred with 217 children, and this confirmed the positive test in 139 children (hit rate: 64%). In most cases, a temporary conductive hearing loss due to external or middle ear problems (glue ear, tube dysfunction, cerumen, otitis media) was diagnosed. A sensorineural hearing loss was found in 4 children (in 3 of them bilateral). The need for therapy was recognized in 81 children (4% of all screened). Pre-school hearing screening identifies children with ear and hearing problems that need therapeutical intervention. Although the hearing problems are mostly of a temporary nature, some may require monitoring over some period. Also some children with permanent sensorineural hearing loss may be detected through this measure. Hearing screening is an efficient means of assessing ear and hearing problems in pre-school children. However, the follow-up rate needs to be improved for optimizing the efficacy.

Hydrotreatment of heavy oil from coal liquefaction on Sulfide Ni - W Catalysts

Energy Technology Data Exchange (ETDEWEB)

Zhi-ping Lei; Li-juan Gao; Heng-fu Shui; Shi-biao, Ren; Zhi-cai Wang; Kang-shi Gang, E-mail: shhf@ahut.edu.c [Anhui University of Technology, Maanshan (China). School of Chemistry and Chemical Engineering. Anhui Key Lab. of Coal Clean Conversion and Utilization

2011-07-01

Heavy oil (distillation temperature: 320-340 deg C) derived from the direct coal liquefaction process using Shengli coal were hydrotreated using sulfided Ni-Mo/Al{sub 2}O{sub 3}, Ni-W/Al{sub 2}O{sub 3}, and Ni-W/SiO{sub 2} catalysts respectively. The sulfided catalysts were characterized by BET, XRD, H{sub 2}-TPR and NH{sub 3}-TPD respectively. The evaluations of the hydrodenitrogenation (HDN) and hydrodearomatization (HDA) properties of heavy oil on the three catalysts were carried out at 400 deg C and 5.0 MPa initial H2 pressure. The W-based catalysts displayed better performances than Mo-based catalysts for the HDN and HDA reactions. Al{sub 2}O{sub 3} supported catalysts were found to have higher catalytic activities than on SiO{sub 2} supported ones. The activities of sulfided catalysts were associated mainly with the nature of active sites, acidity, metal sulfide crystallite size and the amount of the reducible sulfur species of metal sulfide. (author)

Synthesis H-Zeolite catalyst by impregnation KI/KIO3 and performance test catalyst for biodiesel production

Science.gov (United States)

Widayat, W.; Rizky Wicaksono, Adit; Hakim Firdaus, Lukman; Okvitarini, Ndaru

2016-02-01

The objective of this research is to produce H-catalyst catalyst that was impregnated with KI/KIO3. The catalyst was analyzed about surface area, X-Ray Diffraction (XRD) and performance test of catalyst for biodiesel production. An H-Zeolite catalyst was synthesized from natural zeolite with chemical treatment processing, impregnation KI/KIO3 and physical treatment. The results shows that the surface area of the catalyst by 27.236 m2/g at a concentration of 5% KI. XRD analysis shows peak 2-θ at 23.627o indicating that KI was impregnated on H-zeolite catalyst. The catalyst was tested in production of biodiesel using palm oil with conventional methods for 3 hour at temperature of 70-80 oC. The result for conversion Fatty Acid Methyl Ester (FAME) reached maximum value on 87.91% under production process using catalyst 5% KIO3-H zeolite.

Regeneration of LOHC dehydrogenation catalysts: In-situ IR spectroscopy on single crystals, model catalysts, and real catalysts from UHV to near ambient pressure

International Nuclear Information System (INIS)

Amende, Max; Kaftan, Andre; Bachmann, Philipp; Brehmer, Richard; Preuster, Patrick; Koch, Marcus

2016-01-01

Graphical abstract: - Highlights: • We examine the regeneration of Pt-based catalysts poisoned by LOHC degradation. • A microscopic mechanism of the removal of degradation products from Pt is proposed. • Results of our UHV studies on model catalysts are transferred to real catalysis. • Oxidative regeneration of Pt/alumina is possible under mild conditions (600 K). • The degree and temperature regime of regeneration depends on the catalyst morphology. - Abstract: The Liquid Organic Hydrogen Carrier (LOHC) concept offers an efficient route to store hydrogen using organic compounds that are reversibly hydrogenated and dehydrogenated. One important challenge towards application of the LOHC technology at a larger scale is to minimize degradation of Pt-based dehydrogenation catalysts during long-term operation. Herein, we investigate the regeneration of Pt/alumina catalysts poisoned by LOHC degradation. We combine ultrahigh vacuum (UHV) studies on Pt(111), investigations on well-defined Pt/Al_2O_3 model catalysts, and near-ambient pressure (NAP) measurements on real core–shell Pt/Al_2O_3 catalyst pellets. The catalysts were purposely poisoned by reaction with the LOHC perhydro-dibenzyltoluene (H18-MSH) and with dicyclohexylmethane (DCHM) as a simpler model compound. We focus on oxidative regeneration under conditions that may be applied in real dehydrogenation reactors. The degree of poisoning and regeneration under oxidative reaction conditions was quantified using CO as a probe molecule and measured by infrared reflection-absorption spectroscopy (IRAS) and diffuse reflectance Fourier transform IR spectroscopy (DRIFTS) for planar model systems and real catalysts, respectively. We find that regeneration strongly depends on the composition of the catalyst surface. While the clean surface of a poisoned Pt(111) single crystal is fully restored upon thermal treatment in oxygen up to 700 K, contaminated Pt/Al_2O_3 model catalyst and core–shell pellet were only

Regeneration of LOHC dehydrogenation catalysts: In-situ IR spectroscopy on single crystals, model catalysts, and real catalysts from UHV to near ambient pressure

Energy Technology Data Exchange (ETDEWEB)

Amende, Max, E-mail: max.amende@fau.de [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Kaftan, Andre, E-mail: andre.kaftan@fau.de [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Bachmann, Philipp, E-mail: philipp.bachmann@fau.de [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Brehmer, Richard, E-mail: richard.brehmer@fau.de [Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Preuster, Patrick, E-mail: patrick.preuster@fau.de [Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Koch, Marcus, E-mail: marcus.koch@crt.cbi.uni-erlangen.de [Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); and others

2016-01-01

Graphical abstract: - Highlights: • We examine the regeneration of Pt-based catalysts poisoned by LOHC degradation. • A microscopic mechanism of the removal of degradation products from Pt is proposed. • Results of our UHV studies on model catalysts are transferred to real catalysis. • Oxidative regeneration of Pt/alumina is possible under mild conditions (600 K). • The degree and temperature regime of regeneration depends on the catalyst morphology. - Abstract: The Liquid Organic Hydrogen Carrier (LOHC) concept offers an efficient route to store hydrogen using organic compounds that are reversibly hydrogenated and dehydrogenated. One important challenge towards application of the LOHC technology at a larger scale is to minimize degradation of Pt-based dehydrogenation catalysts during long-term operation. Herein, we investigate the regeneration of Pt/alumina catalysts poisoned by LOHC degradation. We combine ultrahigh vacuum (UHV) studies on Pt(111), investigations on well-defined Pt/Al{sub 2}O{sub 3} model catalysts, and near-ambient pressure (NAP) measurements on real core–shell Pt/Al{sub 2}O{sub 3} catalyst pellets. The catalysts were purposely poisoned by reaction with the LOHC perhydro-dibenzyltoluene (H18-MSH) and with dicyclohexylmethane (DCHM) as a simpler model compound. We focus on oxidative regeneration under conditions that may be applied in real dehydrogenation reactors. The degree of poisoning and regeneration under oxidative reaction conditions was quantified using CO as a probe molecule and measured by infrared reflection-absorption spectroscopy (IRAS) and diffuse reflectance Fourier transform IR spectroscopy (DRIFTS) for planar model systems and real catalysts, respectively. We find that regeneration strongly depends on the composition of the catalyst surface. While the clean surface of a poisoned Pt(111) single crystal is fully restored upon thermal treatment in oxygen up to 700 K, contaminated Pt/Al{sub 2}O{sub 3} model catalyst and

Development and Comparison of the Substrate Scope of Pd-Catalysts for the Aerobic Oxidation of Alcohols

Science.gov (United States)

Schultz, Mitchell J.; Hamilton, Steven S.; Jensen, David R.; Sigman, Matthew S.

2009-01-01

Three catalysts for aerobic oxidation of alcohols are discussed and the effectiveness of each is evaluated for allylic, benzylic, aliphatic, and functionalized alcohols. Additionally, chiral nonracemic substrates as well as chemoselective and diastereoselective oxidations are investigated. In this study, the most convenient system for the Pd-catalyzed aerobic oxidation of alcohols is Pd(OAc)2 in combination with triethylamine. This system functions effectively for the majority of alcohols tested and uses mild conditions (3 to 5 mol % of catalyst, room temperature). Pd(IiPr)(OAc)2(H2O) (1) also successfully oxidizes the majority of alcohols evaluated. This system has the advantage of significantly lowering catalyst loadings but requires higher temperatures (0.1 to 1 mol % of catalyst, 60 °C). A new catalyst is also disclosed, Pd(IiPr)(OPiv)2 (2). This catalyst operates under very mild conditions (1 mol %, room temperature, and air as the O2 source) but with a more limited substrate scope. PMID:15844968

On the Preparation and Testing of Fuel Cell Catalysts Using the Thin Film Rotating Disk Electrode Method.

Science.gov (United States)

Inaba, Masanori; Quinson, Jonathan; Bucher, Jan Rudolf; Arenz, Matthias

2018-03-16

We present a step-by-step tutorial to prepare proton exchange membrane fuel cell (PEMFC) catalysts, consisting of Pt nanoparticles (NPs) supported on a high surface area carbon, and to test their performance in thin film rotating disk electrode (TF-RDE) measurements. The TF-RDE methodology is widely used for catalyst screening; nevertheless, the measured performance sometimes considerably differs among research groups. These uncertainties impede the advancement of new catalyst materials and, consequently, several authors discussed possible best practice methods and the importance of benchmarking. The visual tutorial highlights possible pitfalls in the TF-RDE testing of Pt/C catalysts. A synthesis and testing protocol to assess standard Pt/C catalysts is introduced that can be used together with polycrystalline Pt disks as benchmark catalysts. In particular, this study highlights how the properties of the catalyst film on the glassy carbon (GC) electrode influence the measured performance in TF-RDE testing. To obtain thin, homogeneous catalyst films, not only the catalyst preparation, but also the ink deposition and drying procedures are essential. It is demonstrated that an adjustment of the ink's pH might be necessary, and how simple control measurements can be used to check film quality. Once reproducible TF-RDE measurements are obtained, determining the Pt loading on the catalyst support (expressed as Pt wt%) and the electrochemical surface area is necessary to normalize the determined reaction rates to either surface area or Pt mass. For the surface area determination, so-called CO stripping, or the determination of the hydrogen underpotential deposition (Hupd) charge, are standard. For the determination of the Pt loading, a straightforward and cheap procedure using digestion in aqua regia with subsequent conversion of Pt(IV) to Pt(II) and UV-vis measurements is introduced.

Screening for Specific Language Impairment in Preschool Children: Evaluating a Screening Procedure Including the Token Test

Science.gov (United States)

Willinger, Ulrike; Schmoeger, Michaela; Deckert, Matthias; Eisenwort, Brigitte; Loader, Benjamin; Hofmair, Annemarie; Auff, Eduard

2017-01-01

Specific language impairment (SLI) comprises impairments in receptive and/or expressive language. Aim of this study was to evaluate a screening for SLI. 61 children with SLI (SLI-children, age-range 4-6 years) and 61 matched typically developing controls were tested for receptive language ability (Token Test-TT) and for intelligence (Wechsler…

Hydroprocessing full-range of heavy oils and bitumen using ultradispersed catalysts at low severity

Science.gov (United States)

Peluso, Enzo

The progressive exhaustion of light crude oils is forcing the petroleum industry to explore new alternatives for the exploitation of unconventional oils. New approaches are searching for technologies able to produce, transport and refine these feedstocks at lower costs, in which symbiotic processes between the enhanced oil recovery (EOR) and the conventional upgrading technologies are under investigation. The process explored in this thesis is an interesting alternative for in-situ upgrading of these crude oils in the presence of ultradispersed (UD) catalysts, which are included as a disperse phase able to circulate along with the processed feed. The objectives of this work are: (a) study the performance of UD catalysts in the presence of a full range (non fractioned) heavy oil and bitumen and (b) evaluate the recyclability of the UD catalysts. Four different heavy crude oils were evaluated in the presence with UD catalysts at a total pressure of 2.8 MPa, residence time of 8 hours and reaction temperatures from 360 up to 400ºC. Thermal and catalytic hydro-processing were compared in terms of conversion and product stability. A comparison between the different crude oils was additionally derived in terms of SARA, initial micro-carbon content and virgin oil stability among other properties. Advantages of catalytic hydro-processing over thermal hydro-processing were evidenced, with UD catalysts playing an essential hydrogenating role while retarding coke formation; microcarbon and asphaltenes reduction in the presence of UD catalysts was observed. To evaluate the feasibility of recycling the UD catalysts, a micro-slurry recycled unit was developed as part of this research. These main results showed: (a) a successful design of this unit, (b) that temperature, LHSV and fractional recycling ratio have more impact on VGO conversion, while pressure has almost no effect, and (c) an UD catalysts agglomeration process was detected, however this process is slow and reversible.

In situ Generated Ruthenium Catalyst Systems Bearing Diverse N-Heterocyclic Carbene Precursors for Atom-Economic Amide Synthesis from Alcohols and Amines.

Science.gov (United States)

Cheng, Hua; Xiong, Mao-Qian; Cheng, Chuan-Xiang; Wang, Hua-Jing; Lu, Qiang; Liu, Hong-Fu; Yao, Fu-Bin; Chen, Cheng; Verpoort, Francis

2018-02-16

The transition-metal-catalyzed direct synthesis of amides from alcohols and amines is herein demonstrated as a highly environmentally benign and atom-economic process. Among various catalyst systems, in situ generated N-heterocyclic carbene (NHC)-based ruthenium (Ru) halide catalyst systems have been proven to be active for this transformation. However, these existing catalyst systems usually require an additional ligand to achieve satisfactory results. In this work, through extensive screening of a diverse variety of NHC precursors, we discovered an active in situ catalyst system for efficient amide synthesis without any additional ligand. Notably, this catalyst system was found to be insensitive to the electronic effects of the substrates, and various electron-deficient substrates, which were not highly reactive with our previous catalyst systems, could be employed to afford the corresponding amides efficiently. Furthermore, mechanistic investigations were performed to provide a rationale for the high activity of the optimized catalyst system. NMR-scale reactions indicated that the rapid formation of a Ru hydride intermediate (signal at δ=-7.8 ppm in the 1 H NMR spectrum) after the addition of the alcohol substrate should be pivotal in establishing the high catalyst activity. Besides, HRMS analysis provided possible structures of the in situ generated catalyst system. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structural building screening and evaluation

Science.gov (United States)

Kurniawandy, Alex; Nakazawa, Shoji; Hendry, Andy; Ridwan, Firdaus, Rahmatul

2017-10-01

An earthquake is a disaster that can be harmful to the community, such as financial loss and also dead injuries. Pekanbaru is a city that located in the middle of Sumatera Island. Even though the city of Pekanbaru is a city that rarely occurs earthquake, but Pekanbaru has ever felt the impact of the big earthquake that occurred in West Sumatera on September 2009. As we know, Indonesia located between Eurasia plate, Pacific plate, and Indo-Australian plate. Particularly the Sumatera Island, It has the Semangko fault or the great Sumatra fault along the island from north to south due to the shift of Eurasia and Indo-Australian Plates. An earthquake is not killing people but the building around the people that could be killing them. The failure of the building can be early prevented by doing an evaluation. In this research, the methods of evaluation have used a guideline for the Federal Emergency Management Agency (FEMA) P-154 and Applied Technology Council (ATC) 40. FEMA P-154 is a rapid visual screening of buildings for potential seismic hazards and ATC-40 is seismic evaluation and retrofit of Concrete Buildings. ATC-40 is a more complex evaluation rather than FEMA P-154. The samples to be evaluated are taken in the surroundings of Universitas Riau facility in Pekanbaru. There are four buildings as case study such as the rent student building, the building of mathematics and natural science faculty, the building teacher training and education faculty and the buildings in the faculty of Social political sciences. Vulnerability for every building facing an earthquake is different, this is depending on structural and non-structural components of the building. Among all of the samples, only the building of mathematics and the natural science faculty is in critical condition according to the FEMA P-154 evaluation. Furthermore, the results of evaluation using ATC-40 for the teacher training building are in damage control conditions, despite the other three buildings are

Biodiesel production from non-edible Silybum marianum oil using heterogeneous solid base catalyst under ultrasonication.

Science.gov (United States)

Takase, Mohammed; Chen, Yao; Liu, Hongyang; Zhao, Ting; Yang, Liuqing; Wu, Xiangyang

2014-09-01

The aim of this study is to investigate modified TiO2 doped with C4H4O6HK as heterogeneous solid base catalyst for transesterification of non-edible, Silybum marianum oil to biodiesel using methanol under ultrasonication. Upon screening the catalytic performance of modified TiO2 doped with different K-compounds, 0.7 C4H4O6HK doped on TiO2 was selected. The preparation of the catalyst was done using incipient wetness impregnation method. Having doped modified TiO2 with C4H4O6HK, followed by impregnation, drying and calcination at 600 °C for 6 h, the catalyst was characterized by XRD, FTIR, SEM, BET, TGA, UV and the Hammett indicators. The yield of the biodiesel was proportional to the catalyst basicity. The catalyst had granular and porous structures with high basicity and superior performance. Combined conditions of 16:1 molar ratio of methanol to oil, 5 wt.% catalyst amount, 60 °C reaction temperature and 30 min reaction time was enough for maximum yield of 90.1%. The catalyst maintained sustained activity after five cycles of use. The oxidative stability which was the main problem of the biodiesel was improved from 2.0 h to 3.2h after 30 days using ascorbic acid as antioxidant. The other properties including the flash point, cetane number and the cold flow ones were however, comparable to international standards. The study indicated that Ti-0.7-600-6 is an efficient, economical and environmentally, friendly catalyst under ultrasonication for producing biodiesel from S. marianum oil with a substantial yield. Copyright © 2014 Elsevier B.V. All rights reserved.

Visible Light Responsive Catalysts Using Quantum Dot-Modified Ti02 for Air and Water Purification

Science.gov (United States)

Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.; Hintze, paul; Clausen, Christian

2012-01-01

The method of photocatalysis utilizing titanium dioxide, TiO2, as the catalyst has been widely studied for trace contaminant control for both air and water applications because of its low energy consumption and use of a regenerable catalyst. Titanium dioxide requires ultraviolet light for activation due to its band gap energy of 3.2 eV. Traditionally, Hg-vapor fluorescent light sources are used in PCO reactors and are a setback for the technology for space application due to the possibility of Hg contamination. The development of a visible light responsive (VLR) TiO2-based catalyst could lead to the use of solar energy in the visible region (approx.45% of the solar spectrum lies in the visible region; > 400 nm) or highly efficient LEDs (with wavelengths > 400 nm) to make PCO approaches more efficient, economical, and safe. Though VLR catalyst development has been an active area of research for the past two decades, there are few commercially available VLR catalysts; those that are available still have poor activity in the visible region compared to that in the UV region. Thus, this study was aimed at the further development of VLR catalysts by a new method - coupling of quantum dots (QD) of a narrow band gap semiconductor (e.g., CdS, CdSe, PbS, ZnSe, etc.) to the TiO2 by two preparation methods: 1) photodeposition and 2) mechanical alloying using a high-speed ball mill. A library of catalysts was developed and screened for gas and aqueous phase applications, using ethanol and 4-chlorophenol as the target contaminants, respectively. Both target compounds are well studied in photocatalytic systems serve as model contaminants for this research. Synthesized catalysts were compared in terms of preparation method, type of quantum dots, and dosage of quantum dots.

Evaluation of the efficacy of six nutritional screening tools to predict malnutrition in the elderly.

Science.gov (United States)

Poulia, Kalliopi-Anna; Yannakoulia, Mary; Karageorgou, Dimitra; Gamaletsou, Maria; Panagiotakos, Demosthenes B; Sipsas, Nikolaos V; Zampelas, Antonis

2012-06-01

Malnutrition in the elderly is a multifactorial problem, more prevalent in hospitals and care homes. The absence of a gold standard in evaluating nutritional risk led us to evaluate the efficacy of six nutritional screening tools used in the elderly. Two hundred forty eight elderly patients (129 men, 119 female women, aged 75.2 ± 8.5 years) were examined. Nutritional screening was performed on admission using the following tools: Nutritional Risk Index (NRI), Geriatric Nutritional Risk Index (GNRI), Subjective Global Assessment (SGA), Mini Nutritional Assessment - Screening Form (MNA-SF), Malnutrition Universal Screening Tool (MUST) and Nutritional Risk Screening 2002 (NRS 2002). A combined index for malnutrition was also calculated. Nutritional risk and/or malnutrition varied greatly, ranging from 47.2 to 97.6%, depending on the nutritional screening tool used. MUST was the most valid screening tool (validity coefficient = 0.766, CI 95%: 0.690-0.841), while SGA was in better agreement with the combined index (κ = 0.707, p = 0.000). NRS 2002 although was the highest in sensitivity (99.4%), it was the lowest in specificity (6.1%) and positive predictive value (68.2%). MUST seem to be the most valid in the evaluation of the risk for malnutrition in the elderly upon admission to the hospital. NRS 2002 was found to overestimate nutritional risk in the elderly. Copyright © 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Alkaline earth layered benzoates as reusable heterogeneous catalysts for the methyl esterification of benzoic acid

Directory of Open Access Journals (Sweden)

Swamy Arêa Maruyama

2012-01-01

Full Text Available This paper describes the synthesis and characterization of layered barium, calcium and strontium benzoates and evaluates the potential of these materials as catalysts in the synthesis of methyl benzoate. The methyl esterification of benzoic acid was investigated, where the effects of temperature, alcohol:acid molar ratio and amount of catalyst were evaluated. Ester conversions of 65 to 70% were achieved for all the catalysts under the best reaction conditions. The possibility of recycling these metallic benzoates was also demonstrated, evidenced by unaltered catalytic activity for three consecutive reaction cycles.

Clinical evaluation of mammography using a screen-film system. Pt. 3

International Nuclear Information System (INIS)

Wurm, J.; Behrends, E.; Hofmann-Preiss, K.; Paterok, E.M.; Saebel, M.; Weishaar, J.

1983-01-01

In a clinical image quality test, the parameter image quality is analysed using the ROC method and on the basis of mammograms already classified by means of histological findings into ''benign'' and ''malignant'' cases. The results of this analysis confirmed those of the first two studies: The screen-film system, due to its almost equally good image quality, achieves a diagnostic accuracy as good as the Definix test film without screen. In addition, the following two parameters have been investigated in this clinical test: Different knowledge and experience of the evaluating experts in the field of mammography, and the learning progress in the course of expert training. The difference in knowledge and experience of the various evaluators becomes apparent in ROC analysis only with an evaluator having much more experience than the others in the field of mammography. The parameter learning progress - as shown by repeating the evaluation after three months of intensive training - does not come forth clear enough in the ROC curves. An analysis of the frequency distribution of the five decision thresholds reveals the approach of the individual evaluator. (orig.) [de

A comparative study on the influence of the platinum catalyst in poly(dimethylsiloxane) based networks synthesis

DEFF Research Database (Denmark)

Bejenariu, Anca Gabriela; Poulsen, Julie Øblom; Skov, Anne Ladegaard

2009-01-01

The aim of the project is to find the best of three Pt catalysts and their appropriate quantity in order to obtain soft networks in one hour at room temperature. How the choice of catalyst influences the final elastomeric properties is also evaluated. The differences between the catalysts...

Practical, economical, and eco-friendly starch-supported palladium catalyst for Suzuki coupling reactions.

Science.gov (United States)

Baran, Talat

2017-06-15

In catalytic systems, the support materials need to be both eco friendly and low cost as well as having high thermal and chemical stability. In this paper, a novel starch supported palladium catalyst, which had these outstanding properties, was designed and its catalytic activity was evaluated in a Suzuki coupling reaction under microwave heating with solvent-free and mild reaction conditions. The starch supported catalyst gave remarkable reaction yields after only 5min as a result of the coupling reaction of the phenyl boronic acid with 23 different substrates, which are bearing aril bromide, iodide, and chloride. The longevity of the catalyst was also investigated, and the catalyst could be reused for 10 runs. The starch supported Pd(II) catalyst yielded remarkable TON (up to 25,000) and TOF (up to 312,500) values by using a simple, fast and eco-friendly method. In addition, the catalytic performance of the catalyst was tested against different commercial palladium catalysts, and the green starch supported catalyst had excellent selectivity. The catalytic tests showed that the novel starch based palladium catalyst proved to be an economical and practical catalyst for the synthesis of biaryl compounds. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of a screening instrument for essential tremor

DEFF Research Database (Denmark)

Lorenz, Delia; Papengut, Frank; Frederiksen, Henrik

2008-01-01

To evaluate a screening instrument for essential tremor (ET) consisting of a seven-item questionnaire and a spiral drawing. A total of 2,448 Danish twins aged 70 years or more and a second sample aged 60 years or more (n = 1,684) from a population-based northern German cross-sectional study (Pop....... Definite or probable ET was diagnosed in 104 patients, possible in 86 and other tremors in 98 patients. The sensitivity of the screening instrument was 70.5%, the positive predictive value was 64.9%, the specificity was 68.2%, and the negative predictive value was 73.5%. Tremor severity correlated...... significantly with higher spiral scores and more positive items. More patients were identified by spiral drawing in all tremor groups. The interrater and intrarater reliability for spirals ranged from 0.7 to 0.8 using intraclass coefficient. A cluster analysis revealed that the questionnaire can be reduced...

More active and sulfur resistant bimetallic Pd-Ni catalysts

Energy Technology Data Exchange (ETDEWEB)

Betti, Carolina; Carrara, Nicolás; Badano, Juan; Lederhos, Cecilia; Vera, Carlos; Quiroga, Mónica, E-mail: mquiroga@fiq.unl.edu.ar [Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (FIQ-UNL, CONICET), Santa Fe (Argentina)

2018-02-15

The influence of the kind of metal precursor and the sequence of impregnation on the properties of Pd-Ni catalysts was evaluated during the test reaction of selective hydrogenation of styrene to ethylbenzene by means of physicochemical characterization. The focus was put on the final hydrogenating activity and the resistance to deactivation by sulfide compounds (thiophene). The used techniques of characterization were ICP, XPS, XDR, TPR, CO chemisorption and TEM. XPS results indicated the presence of different Pd species: Pd{sup δ-}, Pd{sup 0} and Pd{sup δ+}. In the case of the Ni containing catalysts, Ni{sup 0} and NiO species were also detected. These palladium and nickel species would be responsible of the variation of activity and sulfur resistance of the catalysts. NiClPd catalysts had a higher resistance to deactivation by sulfur poisoning. This was associated to a higher concentration of Pd{sup η+}Cl{sub x}O{sub y} species that would prevent the adsorption of thiophene by both steric and electronic effects. It could also be due to the lower concentration of Pd{sup 0} and Ni{sup 0} on these catalysts, as compared to those shown by the PdNiCl catalysts. Both the Pd{sup 0} and Ni{sup 0} species are more prone to poisoning because of their higher electronic availability. (author)

Spent catalyst waste management. A review. Part 1. Developments in hydroprocessing catalyst waste reduction and use

Energy Technology Data Exchange (ETDEWEB)

Marafi, M.; Stanislaus, A. [Petroleum Refining Department, Petroleum Research and Studies Center, Kuwait Institute for Scientific Research, P.O. Box 24885, 13109-Safat (Kuwait)

2008-04-15

Solid catalysts containing metals, metal oxides or sulfides, which play a key role in the refining of petroleum to clean fuels and many other valuable products, become solid wastes after use. In many refineries, the spent catalysts discarded from hydroprocessing units form a major part of these solid wastes. Disposal of spent hydroprocessing catalysts requires compliance with stringent environmental regulations because of their hazardous nature and toxic chemicals content. Various options such as minimizing spent catalyst waste generation by regeneration and reuse, metals recovery, utilization to produce useful materials and treatment for safe disposal, could be considered to deal with the spent catalyst environmental problem. In this paper, information available in the literature on spent hydroprocessing catalyst waste reduction at source by using improved more active and more stable catalysts, regeneration, rejuvenation and reuse of deactivated catalysts in many cycles, and reusing in other processes are reviewed in detail with focus on recent developments. Available methods for recycling of spent hydroprocessing catalysts by using them as raw materials for the preparation of active new catalysts and many other valuable products are also reviewed. (author)

Evaluation report on the design of solid catalysts for saving energy in petrochemical industry; Sekiyu kagaku no tame no sho energy gata kotai shokubai sekkei hyoka hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

The aim is to improve on hydrocarbon oxidation which is a difficult reaction (analogous to combustion and having potential for heat generation or explosion, with restrictions therefore imposed on reaction conditions) by use of a catalyst supporting porous membrane. The fiscal 1999-2000 results are stated. In this effort, the target reaction is promoted by a catalyst supported by a porous membrane while combustion is controlled by the said porous membrane that separates oxygen and hydrocarbon from each other. Such a design was not available since a catalyst supporting inorganic membrane withstanding so high a temperature was difficult to prepare. Recently, however, a porous membrane with its pores regulated to microstructural dimensions was developed. The activity of a Pd membrane catalyst is evaluated in view of the degree of oxidation of propylene, cyclohexene, and benzene. It is then found that hydrogen that has passed the Pd membrane participates in the reaction. In a propylene oxidation test using a membrane type Ag/Al{sub 2}O{sub 3} catalyst, it is found that acetone is generated and that oxygen after passing through the membrane participates in the reaction. Methods are studied for preparing a metal membrane in which the catalyst system comprises a catalyst supporting porous membrane and a Pd membrane. In the fabrication of metal membranes, a highly selective hydrogen permeable membrane is stably prepared by the thermal CVD (chemical vapor deposition) method. (NEDO)

The stability evaluation of lime mud as transesterification catalyst in resisting CO2 and H2O for biodiesel production

International Nuclear Information System (INIS)

Li, Hui; Niu, Sheng-li; Lu, Chun-mei; Cheng, Shi-qing

2015-01-01

Highlights: • Lime mud (LM) is pretreated with calcination, hydration and desiccation. • The alkali solubility is the amount of alkali compounds dissolved in methanol. • The soluble alkali amount in LM700-H is higher than that of CaO–H. • LM700 possesses a stronger capability than CaO in resisting H 2 O and CO 2 . - Abstract: The most outstanding property of the heterogeneous transesterification catalysts is recyclable, but their catalytic activity may be depressed for the absorption of moisture (H 2 O) and carbon dioxide (CO 2 ) in air, especially for the basic ones. Lime mud (LM) is effective in catalyzing transesterification, yet its property in resisting H 2 O and CO 2 is indistinct, which should be emphasized. In this study, the LM based transesterification catalyst is prepared through calcinations. Then, it is hydrated and desiccated to simulate the contamination by H 2 O and CO 2 . Further, the fresh and the contaminated catalysts are characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Hammette indicator, Brunauer–Emmett–Teller (BET) surface area and soluble alkali examination, to reveal the mechanism of LM in resisting H 2 O and CO 2 . Meanwhile, the analytical grade calcium oxide (CaO) is chosen for comparison. Finally, to comprehensively investigate the influences of H 2 O and CO 2 on LM in catalyzing transesterification, the factors of the catalyst addition percentage, molar ratio of methanol to oil and transesterification temperature are evaluated

A new bonded catalyst for safe lithium-thionyl chloride batteries

Science.gov (United States)

Walsh, F.; Hopewood, J.

1982-08-01

The goal of the research effort was to demonstrate that a new class of organometallic cathode catalysts, the TAAs, are stable in thionyl chloride and that they significantly improve the power performance of lithium-thionyl chloride primary batteries. A number of TAAs were evaluated and shown to be active catalysts. Included in this evaluation were TAAs which were covalently bonded to the supporting carbon electrode material; a covalently bonded catalyst has the potential advantage that it will not dissolve into the electrolyte and negatively affect anode performance. During the six month research program, the TAAS were shown to: significantly improve cathode performance in Li/SOCl2 cells; improve cathode capacity; improve cathode performance throughout long-term tests; and not affect anode performance. Further work is needed to develop data in cell studies on temperature range, shelf life, voltage delay effects, energy/power density as a function of rate, and factors affecting electrode capacity. Battery performance in stress tests to develop safety and cost data is also needed.

Automotive Catalyst State Diagnosis Using Microwaves

Directory of Open Access Journals (Sweden)

Moos Ralf

2015-01-01

Full Text Available The state of catalysts plays a key role in automotive exhaust gas aftertreatment. The soot or ash loading of Diesel particulate filters, the oxygen loading degree in three-way catalysts, the amount of stored ammonia in SCR catalysts, or the NOx loading degree in NOx storage catalysts are important parameters that are today determined indirectly and in a model-based manner with gas sensors installed upstream and/or downstream of the catalysts. This contribution gives an overview on a novel approach to determine the catalyst state directly by a microwave-based technique. The method exploits the fact that the catalyst housing acts as a microwave cavity resonator. As “sensing” elements, one or two simple antennas are mounted inside the catalyst canning. The electrical properties of the catalyst device (ceramic honeycomb plus coating and storage material can be measured. Preferably, the resonance characteristics, e.g., the resonance frequencies, of selected cavity modes are observed. The information on the catalyst interior obtained in such a contactless manner is very well correlated with the catalyst state as will be demonstrated for different exhaust gas aftertreatment systems.

Development of Ultra-Low Platinum Alloy Cathode Catalysts for PEM Fuel Cells

Energy Technology Data Exchange (ETDEWEB)

Popov, Branko N. [Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemical Engineering; Weidner, John [Univ. of South Carolina, Columbia, SC (United States)

2016-01-07

The goal of this project is to synthesize a low cost PEM fuel cell cathode catalyst and support with optimized average mass activity, stability of mass activity, initial high current density performance under H₂/air (power density), and catalyst and support stability able to meet 2017 DOE targets for electrocatalysts for transportation applications. Pt*/ACCS-2 catalyst was synthesized according to a novel methodology developed at USC through: (i) surface modification, (ii) metal catalyzed pyrolysis and (iii) chemical leaching to remove excess meal used to dope the support. Pt* stands for suppressed platinum catalyst synthesized with Co doped platinum. The procedure results in increasing carbon graphitization, inclusion of cobalt in the bulk and formation of non-metallic active sites on the carbon surface. Catalytic activity of the support shows an onset potential of 0.86 V for the oxygen reduction reaction (ORR) with well-defined kinetic and mass transfer regions and 2.5% H₂O₂ production. Pt*/ACCS-2 catalyst durability under 0.6-1.0 V potential cycling and support stability under 1.0-1.5 V potential cycling was evaluated. The results indicated excellent catalyst and support performance under simulated start-up/shut down operating conditions (1.0 – 1.5 V, 5000 cycles) which satisfy DOE 2017 catalyst and support durability and activity. The 30% Pt*/ACCS-2 catalyst showed high initial mass activity of 0.34 A/mg_PGM at 0.9 ViR-free and loss of mass activity of 45% after 30,000 cycles (0.6-1.0 V). The catalyst performance under H₂-air fuel cell operating conditions showed only 24 mV (iR-free) loss at 0.8 A/cm² with an ECSA loss of 42% after 30,000 cycles (0.6-1.0 V). The support stability under 1.0-1.5 V potential cycling showed mass activity loss of 50% and potential loss of 8 mV (iR-free) at 1.5 A/cm². The ECSA loss was 22% after 5,000 cycles. Furthermore, the Pt*/ACCS-2 catalyst showed an

Catalyst in Basic Oleochemicals

Directory of Open Access Journals (Sweden)

Eva Suyenty

2007-10-01

Full Text Available Currently Indonesia is the world largest palm oil producer with production volume reaching 16 million tones per annum. The high crude oil and ethylene prices in the last 3 – 4 years contribute to the healthy demand growth for basic oleochemicals: fatty acids and fatty alcohols. Oleochemicals are starting to replace crude oil derived products in various applications. As widely practiced in petrochemical industry, catalyst plays a very important role in the production of basic oleochemicals. Catalytic reactions are abound in the production of oleochemicals: Nickel based catalysts are used in the hydrogenation of unsaturated fatty acids; sodium methylate catalyst in the transesterification of triglycerides; sulfonic based polystyrene resin catalyst in esterification of fatty acids; and copper chromite/copper zinc catalyst in the high pressure hydrogenation of methyl esters or fatty acids to produce fatty alcohols. To maintain long catalyst life, it is crucial to ensure the absence of catalyst poisons and inhibitors in the feed. The preparation methods of nickel and copper chromite catalysts are as follows: precipitation, filtration, drying, and calcinations. Sodium methylate is derived from direct reaction of sodium metal and methanol under inert gas. The sulfonic based polystyrene resin is derived from sulfonation of polystyrene crosslinked with di-vinyl-benzene. © 2007 BCREC UNDIP. All rights reserved.[Presented at Symposium and Congress of MKICS 2007, 18-19 April 2007, Semarang, Indonesia][How to Cite: E. Suyenty, H. Sentosa, M. Agustine, S. Anwar, A. Lie, E. Sutanto. (2007. Catalyst in Basic Oleochemicals. Bulletin of Chemical Reaction Engineering and Catalysis, 2 (2-3: 22-31.  doi:10.9767/bcrec.2.2-3.6.22-31][How to Link/DOI: http://dx.doi.org/10.9767/bcrec.2.2-3.6.22-31 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/6

Development and evaluation of a comprehensive screening for orofacial dysfunction.

Science.gov (United States)

Bakke, Merete; Bergendal, Birgitta; McAllister, Anita; Sjögreen, Lotta; Asten, Pamela

2007-01-01

The aim was to develop a comprehensive screening instrument for evaluation of orofacial dysfunction that was easy to perform for different health professionals without special equipment. The Nordic Orofacial Test--Screening (NOT-S), consisting of a structured interview and clinical examination,was developed with a picture manual illustrating the different tasks in the examination. It was first tested in a Swedish version, and later translated to other Nordic languages, and to English. The interview reflected six domains, (I) Sensory function, (II) Breathing, (III) Habits, (IV) Chewing and swallowing, (V) Drooling, and (VI) Dryness of the mouth, and the examination included six domains representing (1) The face at rest, and tasks regarding (2) Nose breathing, (3) Facial expression, (4) Masticatory muscle and jaw function, (5) Oral motor function, and (6) Speech. One or more "yes" for impairment in a domain resulted in one point (maximum NOT-S score 12 points). The mean NOT-S score (+/- SD) in 120 patients (3-86 yr), referred to five centers for specialized dental care or speech and language pathology in Sweden, Norway and Denmark, was 4.1 +/- 2.6, and 0.4 +/- 0.6 in 60 control subjects (3-78 yr). The screening was easy to administer and the time spent 5-13 min. The scores from the clinic-referred sample differed significantly from the controls, and the sensitivity of the screening was 0.96 and specificity 0.63. Repeated evaluations of videotapes of 200 patients by 3 examiners, speech-language pathologists and dentists, with at least two-week intervals, showed inter- and intraexaminer agreement on the points given in the domains at respectively 83% and 92-95% which increased after recalibration to 85% and 95-99%. Kappa values for interexaminer agreement on the NOT-S scores were 0.42-0.44 (i.e. fair), and the method error was 5.3%. To conclude, NOT-S gave a reliable and valid screening for orofacial dysfunction.

Hydroprocessing catalysts utilization and regeneration schemes

Energy Technology Data Exchange (ETDEWEB)

Furimsky, E.

The catalyst reactor inventory represents an important part of the cost of hydroprocessing operation. The selection of a suitable catalyst and reactor is influenced by feedstock properties. Processes ensuring an uninterrupted operation during catalyst addition and withdrawal are preferred for processing high asphaltene and metal content feedstocks. The spent catalyst can be regenerated and returned to the operation if the extent of its deactivation is not high. The regeneration may be performed either in-situ or off-site. The former is suitable for fixed bed reactors whereas the catalyst from ebullated bed reactors must be regenerated off-site. The regeneration of spent catalysts heavily loaded with metals such as V, Ni and Fe may not be economic. Such catalysts may be suitable for metal reclamation. An environmentally safe method for catalyst disposal must be found if neither regeneration nor metal reclamation from spent catalysts can be performed.

Biodiesel fuel production from waste cooking oil using radiation-grafted fibrous catalysts

Science.gov (United States)

Ueki, Yuji; Saiki, Seiichi; Hoshina, Hiroyuki; Seko, Noriaki

2018-02-01

Waste cooking oil, which can be used as a raw material for biodiesel fuel (BDF), contains two kinds of oil components: triglycerides (TGs) and free fatty acids (FFAs). Therefore, both alkaline-type and acid-type catalysts are needed to produce BDF from waste cooking oil. In this study, an alkaline-type grafted fibrous catalyst bearing OH- ions was synthesized by radiation-induced emulsion grafting of 4-chloromethylstyrene onto a polyethylene-coated polypropylene (PE/PP) nonwoven fabric, amination with trimethylamine, and further treatment with NaOH. Furthermore, an acid-type catalyst bearing H+ ions was synthesized by radiation-induced emulsion grafting of ethyl p-styrenesulfonate onto a PE/PP nonwoven fabric, saponification with NaOH, and protonation with HNO3. The OH- and H+ densities of the grafted fibrous catalysts were controlled by the grafting yield. The maximum OH- and H+ densities of the catalysts were 3.6 mmol-OH-/g-catalyst and 3.4 mmol-H+/g-catalyst, respectively. The performances of the catalysts were evaluated in the batchwise transesterification of TGs and ethanol, and the batchwise esterification of FFAs and ethanol. In both cases, TGs and FFAs were gradually converted into BDF. The mixed oil and four actual waste cooking oils, which contained both TGs and FFAs, were completely converted into BDF by sequential catalytic reactions with the acid-type grafted fibrous catalyst and then the alkaline-type grafted fibrous catalyst.

Alternative alkali resistant deNOx catalysts

DEFF Research Database (Denmark)

Putluru, Siva Sankar Reddy; Kristensen, Steffen Buus; Due-Hansen, Johannes

2012-01-01

by onepot sol–gel method. All catalysts were characterized by BET, XRPD and NH3-TPD. Initial SCR activities of 8 out of 9 catalysts showed higher NO conversion at least at one temperature in the temperature range 300–500 ◦C compared to the conventional V2O5-WO3/TiO2 catalyst. After potassium poisoning (100......Alternative alkali resistant deNOx catalysts were prepared using three different supports ZrO2, TiO2 and Mordenite zeolite. The majority of the catalysts were prepared by incipient wetness impregnation of a commercial support, with vanadium, copper or iron precursor, one catalyst was prepared......–130 µmol of K/g of catalyst) the relative drop in SCR activity and acidity was lower for all the alternative catalysts compared to the industrial V2O5-WO3/TiO2 catalyst. Furthermore, Cu/MOR and Nano-V2O5/Sul-TiO2 catalysts showed 8–16 times higher SCR activities than the conventional even after high...

Screening for Malnutrition in Community Dwelling Older Japanese: Preliminary Development and Evaluation of the Japanese Nutritional Risk Screening Tool (NRST).

Science.gov (United States)

Htun, N C; Ishikawa-Takata, K; Kuroda, A; Tanaka, T; Kikutani, T; Obuchi, S P; Hirano, H; Iijima, K

2016-02-01

Early and effective screening for age-related malnutrition is an essential part of providing optimal nutritional care to older populations. This study was performed to evaluate the adaptation of the original SCREEN II questionnaire (Seniors in the Community: Risk Evaluation for Eating and Nutrition, version II) for use in Japan by examining its measurement properties and ability to predict nutritional risk and sarcopenia in community-dwelling older Japanese people. The ultimate objective of this preliminary validation study is to develop a license granted full Japanese version of the SCREEN II. The measurement properties and predictive validity of the NRST were examined in this cross-sectional study of 1921 community-dwelling older Japanese people. Assessments included medical history, and anthropometric and serum albumin measurements. Questions on dietary habits that corresponded to the original SCREEN II were applied to Nutritional Risk Screening Tool (NRST) scoring system. Nutritional risk was assessed by the Geriatric Nutrition Risk Index (GNRI) and the short form of the Mini-Nutritional Assessment (MNA-SF). Sarcopenia was diagnosed according to the criteria of the European Working Group on Sarcopenia in Older People. The nutritional risk prevalences determined by the GNRI and MNA-SF were 5.6% and 34.7%, respectively. The prevalence of sarcopenia was 13.3%. Mean NRST scores were significantly lower in the nutritionally at-risk than in the well-nourished groups. Concurrent validity analysis showed significant correlations between NRST scores and both nutritional risk parameters (GNRI or MNA-SF) and sarcopenia. The areas under the receiver operating characteristic curves (AUC) of NRST for the prediction of nutritional risk were 0.635 and 0.584 as assessed by GNRI and MNA-SF, respectively. AUCs for the prediction of sarcopenia were 0.602 (NRST), 0.655 (age-integrated NRST), and 0.676 (age and BMI-integrated NRST). These results indicate that the NRST is a

In-situ characterization of heterogeneous catalysts

CERN Document Server

Rodriguez, Jose A; Chupas, Peter J

2013-01-01

Helps researchers develop new catalysts for sustainable fuel and chemical production Reviewing the latest developments in the field, this book explores the in-situ characterization of heterogeneous catalysts, enabling readers to take full advantage of the sophisticated techniques used to study heterogeneous catalysts and reaction mechanisms. In using these techniques, readers can learn to improve the selectivity and the performance of catalysts and how to prepare catalysts as efficiently as possible, with minimum waste. In-situ Characterization of Heterogeneous Catalysts feat

Hydrogenation of Lactic Acid to 1,2-propanediol over Ru-based catalysts

NARCIS (Netherlands)

Liu, K.; Huang, X.; Pidko, E.A.; Hensen, E.J.M.

2018-01-01

The catalytic hydrogenation of lactic acid to 1,2-propanediol with supported Ru catalysts in water was investigated. The influence of catalyst support (activated carbon, γ-Al2O3, SiO2, TiO2, and CeO2) and promoters (Pd, Au, Mo, Re, Sn) on the catalytic performance was evaluated. Catalytic tests

Reuse of Hydrotreating Spent Catalyst

International Nuclear Information System (INIS)

Habib, A.M.; Menoufy, M.F.; Amhed, S.H.

2004-01-01

All hydro treating catalysts used in petroleum refining processes gradually lose activity through coking, poisoning by metal, sulfur or halides or lose surface area from sintering at high process temperatures. Waste hydrotreating catalyst, which have been used in re-refining of waste lube oil at Alexandria Petroleum Company (after 5 years lifetime) compared with the same fresh catalyst were used in the present work. Studies are conducted on partial extraction of the active metals of spent catalyst (Mo and Ni) using three leaching solvents,4% oxidized oxalic acid, 10% aqueous sodium hydroxide and 10% citric acid. The leaching experiments are conducting on the de coked extrude [un crushed] spent catalyst samples. These steps are carried out in order to rejuvenate the spent catalyst to be reused in other reactions. The results indicated that 4% oxidized oxalic acid leaching solution gave total metal removal 45.6 for de coked catalyst samples while NaOH gave 35% and citric acid gave 31.9 % The oxidized leaching agent was the most efficient leaching solvent to facilitate the metal removal, and the rejuvenated catalyst was characterized by the unchanged crystalline phase The rejuvenated catalyst was applied for hydrodesulfurization (HDS) of vacuum gas oil as a feedstock, under different hydrogen pressure 20-80 bar in order to compare its HDS activity

Colorectal cancer screening for average-risk North Americans: an economic evaluation.

Directory of Open Access Journals (Sweden)

Steven J Heitman

Full Text Available BACKGROUND: Colorectal cancer (CRC fulfills the World Health Organization criteria for mass screening, but screening uptake is low in most countries. CRC screening is resource intensive, and it is unclear if an optimal strategy exists. The objective of this study was to perform an economic evaluation of CRC screening in average risk North American individuals considering all relevant screening modalities and current CRC treatment costs. METHODS AND FINDINGS: An incremental cost-utility analysis using a Markov model was performed comparing guaiac-based fecal occult blood test (FOBT or fecal immunochemical test (FIT annually, fecal DNA every 3 years, flexible sigmoidoscopy or computed tomographic colonography every 5 years, and colonoscopy every 10 years. All strategies were also compared to a no screening natural history arm. Given that different FIT assays and collection methods have been previously tested, three distinct FIT testing strategies were considered, on the basis of studies that have reported "low," "mid," and "high" test performance characteristics for detecting adenomas and CRC. Adenoma and CRC prevalence rates were based on a recent systematic review whereas screening adherence, test performance, and CRC treatment costs were based on publicly available data. The outcome measures included lifetime costs, number of cancers, cancer-related deaths, quality-adjusted life-years gained, and incremental cost-utility ratios. Sensitivity and scenario analyses were performed. Annual FIT, assuming mid-range testing characteristics, was more effective and less costly compared to all strategies (including no screening except FIT-high. Among the lifetimes of 100,000 average-risk patients, the number of cancers could be reduced from 4,857 to 1,393 [corrected] and the number of CRC deaths from 1,782 [corrected] to 457, while saving CAN$68 per person. Although screening patients with FIT became more expensive than a strategy of no screening when the

ALKALI RESISTANT CATALYST

DEFF Research Database (Denmark)

2008-01-01

The present invention concerns the selective removal of nitrogen oxides (NOx) from gasses. In particular, the invention concerns a process, a catalyst and the use of a catalyst for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount...... of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of (i) a formed porous superacidic support, said superacidic support having an Hammett acidity stronger than Ho=-12, and (ii) a metal oxide catalytic component deposited on said superacidic support selected from...

Evaluation of a workplace hemochromatosis screening program.

Science.gov (United States)

Stave, G M; Mignogna, J J; Powell, G S; Hunt, C M

1999-05-01

Hemochromatosis is a common inherited disorder of iron metabolism with significant health consequences for the employed population. Although screening for hemochromatosis has been recommended, workplace screening programs remain uncommon. In the first year of a newly initiated corporate screening program, 1968 employees were tested. The screening algorithm included measurement of serum iron and transferrin and subsequent ferritin levels in those employees with elevated iron/transferrin ratios. Thirteen percent of men and 21% of women had elevated iron/transferrin ratios. Of these, 14 men and 2 women had elevated ferritin levels. Of these 16, three had liver biopsies and all three have hemochromatosis. The cost of the screening program was $27,850. The cost per diagnosis was $9283 and the cost per year of life saved was $928. These costs compare very favorably with other common workplace screening programs. Several barriers to obtaining definitive diagnoses on all patients with a positive screening result were identified; strategies to overcome these barriers would further enhance the cost effectiveness of the program. We conclude that workplace hemochromatosis screening is highly cost effective and should be incorporated into health promotion/disease prevention programs.

Visual Fatigue Evaluation: Improvement of Reflected Glare on Touch Screen for Nuclear Power Plant

International Nuclear Information System (INIS)

Liu, Kang Hung; Yang, Chih Wei; Hwang, Sheue Ling; Liou, Jin Liang

2014-01-01

The purpose of this research is to evaluate the visual fatigue of operators caused by glare problems in the main control room of nuclear power plant. Within the limitation in the main control room, reflectors were set under the light source which generates reflected glare on touch screens. Through avoiding the light directly shines on touch screens, reflected glare were eliminated. This research matched up the setting process of reflectors, evaluated the visual fatigue of operators, and collected user's opinions before reflector setting, after the first setting, and after the second setting. The design of reflectors could refer the result of evaluations and the collection of opinions. Nevertheless, the improvement of reflected glare on touch screens could be verified by this evaluations. The result showed that setting reflectors under the light source could eliminate reflected glare effectively, and the visual fatigue was reduced both on subject and object evaluations. However, the setting direction of reflectors has potential effect on operators' visual fatigue, so the real setting of reflectors still need to be evaluated completely. The near point accommodation could reflect the effect of visual fatigue caused by changes of lighting environment. Thus, the verification of new lighting environment according to the near point accommodation is suggested

Breast cancer screening programmes: the development of a monitoring and evaluation system.

Science.gov (United States)

Day, N E; Williams, D R; Khaw, K T

1989-06-01

It is important that the introduction of breast screening is closely monitored. The anticipated effect on breast cancer mortality will take 10 years or more fully to emerge, and will only occur if a succession of more short-term end points are met. Data from the Swedish two-county randomised trial provide targets that should be achieved, following a logical progression of compliance with the initial invitation, prevalence and stage distribution at the prevalence screen, the rate of interval cancers after the initial screen, the pick-up rate and stage distribution at later screening tests, the rate of interval cancers after later tests, the absolute rate of advanced cancer and finally the breast cancer mortality rate. For evaluation purposes, historical data on stage at diagnosis is desirable; it is suggested that tumour size is probably the most relevant variable available in most cases.

Alternative deNO{sub x} catalysts and technologies

Energy Technology Data Exchange (ETDEWEB)

Due-Hansen, J.

2010-06-15

Two approaches are undertaken in the present work to reduce the emission of NO{sub x}: by means of catalytic removal, and by NO absorption in ionic liquids. The commercial catalyst used for the selective catalytic reduction (SCR) of nitrogen oxides exhibits high activity and selectivity towards N{sub 2}. However, the vanadia-titania-based catalyst used is very sensitive to deactivation by alkali-species (primarily potassium), which are typically present in high amounts in the flue gas when biomass is combusted. By co-firing with large amounts of CO{sub 2}-neutral straw or wood (to meet stringent CO{sub 2} emission legislation), the lifetime of the traditional SCR catalyst is thus significantly reduced due to the presence of deactivating species originating from the fuel. To develop a catalyst less susceptible to the poisons present in the flue gas, a number of catalysts have been synthesized and tested in the present work, all based on commercially available supports. A highly acidic support consisting of sulfated zirconia was chosen based on preliminary studies. A number of different active species distributed on the support were investigated, such as iron, copper and vanadium oxides. However, based on the catalysts performance in the SCR reaction and their resistances towards potassium, the most promising candidate of the formulations studied was the vanadia-loaded catalyst, i.e. V{sub 2}O{sub 5}-SO{sub 4}2-ZrO{sub 2}. This work, together with an introduction to the catalytic removal of NO{sub x}, are described in chapter 3. The remainder of the first part is concerned with the catalytic NO{sub x} removal (chapter 4) and it addresses the upscaling of the best catalyst candidate. The catalyst was mixed with the natural binding clay (sepiolite) to upscale the selected catalyst to the monolithic level, suitable for installation in gas stream with high flows, e.g. a flue gas duct of a power plant. A series of catalyst pellets with increasing levels of sepiolite were

Recycling of waste spent catalyst in road construction and masonry blocks.

Science.gov (United States)

Taha, Ramzi; Al-Kamyani, Zahran; Al-Jabri, Khalifa; Baawain, Mahad; Al-Shamsi, Khalid

2012-08-30

Waste spent catalyst is generated in Oman as a result of the cracking process of petroleum oil in the Mina Al-Fahl and Sohar Refineries. The disposal of spent catalyst is of a major concern to oil refineries. Stabilized spent catalyst was evaluated for use in road construction as a whole replacement for crushed aggregates in the sub-base and base layers and as a partial replacement for Portland cement in masonry blocks manufacturing. Stabilization is necessary as the waste spent catalyst exists in a powder form and binders are needed to attain the necessary strength required to qualify its use in road construction. Raw spent catalyst was also blended with other virgin aggregates, as a sand or filler replacement, for use in road construction. Compaction, unconfined compressive strength and leaching tests were performed on the stabilized mixtures. For its use in masonry construction, blocks were tested for unconfined compressive strength at various curing periods. Results indicate that the spent catalyst has a promising potential for use in road construction and masonry blocks without causing any negative environmental impacts. Copyright © 2012 Elsevier B.V. All rights reserved.

Metal Chlorides Supported Solid Catalysts for F-C Acylations of Arenes

Institute of Scientific and Technical Information of China (English)

李阳; 刘云龙; 穆曼曼; 陈立功

2015-01-01

A series of metal chlorides supported solid catalysts were prepared by simple wet impregnation method. Their catalytic performances for Friedel-Crafts acylation of toluene with benzoyl chloride were evaluated and the excellent results were obtained over FeCl3/SiO2. These catalysts were characterized by BET, NH3-TPD and FT-IR of pyridine adsorption to clarify the structure-activity relationship. It was found that FeCl3/SiO2 has larger pore size and pore volume than other catalysts, which increased the accessibility of the catalyst. In addition, FeCl3/SiO2 ex-hibited higher molar ratio of Lewis acid sites and Brφnsted acid sites, which might be another reason for the in-crease of toluene conversion. Furthermore, the reaction parameters, including temperature, time and molar ratio, were optimized. Under the optimized conditions, 91.2%, conversion and 82.0%, selectivity were obtained. Mean-while, the generality of the catalyst was demonstrated by the acylations of alkyl substituted aromatics. Finally, the catalyst was reused for four runs with slight loss in catalytic activity, which attributed to the drain of the active component.

An optimization study of PtSn/C catalysts applied to direct ethanol fuel cell: Effect of the preparation method on the electrocatalytic activity of the catalysts

Science.gov (United States)

Almeida, T. S.; Palma, L. M.; Leonello, P. H.; Morais, C.; Kokoh, K. B.; De Andrade, A. R.

2012-10-01

The aim of this work was to perform a systematic study of the parameters that can influence the composition, morphology, and catalytic activity of PtSn/C nanoparticles and compare two different methods of nanocatalyst preparation, namely microwave-assisted heating (MW) and thermal decomposition of polymeric precursors (DPP). An investigation of the effects of the reducing and stabilizing agents on the catalytic activity and morphology of Pt75Sn25/C catalysts prepared by microwave-assisted heating was undertaken for optimization purposes. The effect of short-chain alcohols such as ethanol, ethylene glycol, and propylene glycol as reducing agents was evaluated, and the use of sodium acetate and citric acid as stabilizing agents for the MW procedure was examined. Catalysts obtained from propylene glycol displayed higher catalytic activity compared with catalysts prepared in ethylene glycol. Introduction of sodium acetate enhanced the catalytic activity, but this beneficial effect was observed until a critical acetate concentration was reached. Optimization of the MW synthesis allowed for the preparation of highly dispersed catalysts with average sizes lying between 2.0 and 5.0 nm. Comparison of the best catalyst prepared by MW with a catalyst of similar composition prepared by the polymeric precursors method showed that the catalytic activity of the material can be improved when a proper condition for catalyst preparation is achieved.

The Emergence of Manganese-Based Carbonyl Hydrosilylation Catalysts.

Science.gov (United States)

Trovitch, Ryan J

2017-11-21

In recent years, interest in homogeneous manganese catalyst development has intensified because of the earth-abundant and nontoxic nature of this metal. Although compounds of Mn have largely been utilized for epoxidation reactions, recent efforts have revealed that Mn catalysts can mediate a broad range of reductive transformations. Low-valent Mn compounds have proven to be particularly effective for the hydrosilylation of carbonyl- and carboxylate-containing substrates, and this Account aims to highlight my research group's contributions to this field. In our initial 2014 communication, we reported that the bis(imino)pyridine-supported compound ( Ph2PPr PDI)Mn mediates ketone hydrosilylation with exceptional activity under solvent-free conditions. Silanes including Ph 2 SiH 2 , (EtO) 3 SiH, (EtO) 2 MeSiH, and (EtO)Me 2 SiH were found to partially reduce cyclohexanone in the presence of ( Ph2PPr PDI)Mn, while turnover frequencies of up to 1280 min -1 were observed using PhSiH 3 . This led us to evaluate the hydrosilylation of 11 additional ketones and allowed for the atom-efficient preparation of tertiary and quaternary silanes. At that time, it was also discovered that ( Ph2PPr PDI)Mn catalyzes the dihydrosilylation of esters (by way of acyl C-O bond hydrosilylation) to yield a mixture of silyl ethers with modest activity. Earlier this year, the scope of these transformations was extended to aldehydes and formates, and the observed hydrosilylation activities are among the highest obtained for any transition-metal catalyst. The effectiveness of three related catalysts has also been evaluated: ( Ph2PPr PDI)MnH, ( PyEt PDEA)Mn, and [( Ph2PEt PDI)Mn] 2 . To our surprise, ( Ph2PPr PDI)MnH was found to exhibit higher carboxylate dihydrosilylation activity than ( Ph2PPr PDI)Mn, while ( PyEt PDEA)Mn demonstrated remarkable carbonyl hydrosilylation activity considering that it lacks a redox-active supporting ligand. The evaluation of [( Ph2PEt PDI)Mn] 2 revealed

Multifunctional Single-Site Catalysts for Alkoxycarbonylation of Terminal Alkynes.

Science.gov (United States)

Chen, Xingkun; Zhu, Hejun; Wang, Wenlong; Du, Hong; Wang, Tao; Yan, Li; Hu, Xiangping; Ding, Yunjie

2016-09-08

A multifunctional copolymer (PyPPh2 -SO3 H@porous organic polymers, POPs) was prepared by combining acidic groups and heterogeneous P,N ligands through the copolymerization of vinyl-functionalized 2-pyridyldiphenylphosphine (2-PyPPh2 ) and p-styrene sulfonic acid under solvothermal conditions. The morphology and chemical structure of the copolymer were evaluated using a series of characterization techniques. Compared with traditional homogeneous Pd(OAc)2 /2-PyPPh2 / p-toluenesulfonic acid catalyst, the copolymer supported palladium catalyst (Pd-PyPPh2 -SO3 H@POPs) exhibited higher activity for alkoxycarbonylation of terminal alkynes under the same conditions. This phenomenon could be attributed to the synergistic effect between the single-site Pd centers, 2-PyPPh2 ligands, and SO3 H groups, the outstanding swelling properties as well as the high enrichment of the reactant concentration by the porous catalyst. In addition, the catalyst could be reused at least 4 times without any apparent loss of activity. The excellent catalytic reactivity and good recycling properties make it an attractive catalyst for industrial applications. This work paves the way for advanced multifunctional porous organic polymers as a new type of platform for heterogeneous catalysis in the future. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Paraffin Alkylation Using Zeolite Catalysts in a slurry reactor: Chemical Engineering Principles to Extend Catalyst Lifetime

NARCIS (Netherlands)

Jong, K.P. de; Mesters, C.M.A.M.; Peferoen, D.G.R.; Brugge, P.T.M. van; Groot, C. de

1996-01-01

The alkylation of isobutane with 2-butene is carried out using a zeolitic catalyst in a well stirred slurry reactor. Whereas application of fixed bed technology using a solid acid alkylation catalyst has in the led to catalysts lifetimes in the range of minutes, in this work we report catalyst

Hydroxide catalysts for lignin depolymerization

Science.gov (United States)

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

2017-10-17

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.

Hydroxide catalysts for lignin depolymerization

Energy Technology Data Exchange (ETDEWEB)

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.

Electrochemical evaluation of Pt-Based binary catalysts on various supports for the direct methanol fuel cell

CSIR Research Space (South Africa)

Khotseng, L

2016-01-01

Full Text Available Ru/MoO(sub2) > PtSn/TiO(sub2) > PtRu/TiO(sub2). It was also observed that catalysts supported on MWCNTs were more active than those supported on metal oxides. Furthermore, catalysts supported on MWCNTs proved to be more stable than all the other supported...

Ziegler-Natta catalysts for the preparation of polypropylene clay nanocomposites from magnesium ethoxide

International Nuclear Information System (INIS)

Marques, Maria de Fatima V.; Silva, Micheli G. da; Ferreira, Ana Luiza R.

2009-01-01

In the present work, the process for the preparation of Ziegler-Natta catalysts based on MgCl 2 /TiCl 4 was evaluated on the synthesis of isotactic polypropylene. The catalysts were produced by the chemical activation process aiming the morphology control, in order to obtain catalyst particles with spherical form. The synthesis of the catalytic support was accomplished from magnesium ethoxide at different preparation conditions. Commercial clays were also added in the preparation of ZN catalysts, which were employed in propylene polymerization. The purpose was to synthesizing polypropylene nanocomposites by in situ polymerization technique. The results indicated that the developed methods of catalyst preparation were effective, since they have shown high activities and they produced PP with high melting temperatures. It was possible to verify by XRD that the catalytic components were inserted in the clays galleries and the polymers obtained by means of those catalysts are possibly exfoliated nanocomposites. (author)

[Research about re-evaluation of screening of traditonal Chinese medicine symptoms item of post-marketing medicine Xuezhikang].

Science.gov (United States)

He, Wei; Xie, Yanming; Wang, Yongyan

2011-10-01

The purpose of post-marketing Chinese medicine re-evaluation is to identify Chinese medicine clinical indications, while designing scientific and rational of Chinese medicine symptoms items are important to the result of symptoms re-evaluation. This study give screening of traditional Chinese medicine(TCM) symptoms item of post-marketing medicine Xuezhikang re-evaluation as example that reference to principle dyslipidemia clinical research, academic dissertations, Xuezhikang directions, clinical expert practice experience etc. while standardization those symptom names and screening 41 dyslipidemia common symptoms. Furthermore, this paper discuss about the accoerdance and announcements when screening symptoms item, so as to providing a research thread to manufacture PRO chart for post-marketing medicine re-evaluation.

Surface electromyography as a screening method for evaluation of dysphagia and odynophagia

Science.gov (United States)

Vaiman, Michael; Eviatar, Ephraim

2009-01-01

Objective Patients suspected of having swallowing disorders, could highly benefit from simple diagnostic screening before being referred to specialist evaluations. The article analyzes various instrumental methods of dysphagia assessment, introduces surface electromyography (sEMG) to carry out rapid assessment of such patients, and debates proposed suggestions for sEMG screening protocol in order to identify abnormal deglutition. Data sources Subject related books and articles from 1813 to 2007 were obtained through library search, MEDLINE (1949–2007) and EMBASE (1975–2007). Methods Specifics steps for establishing the protocol for applying the technique for screening purposes (e.g., evaluation of specific muscles), the requirements for diagnostic sEMG equipment, the sEMG technique itself, and defining the tests suitable for assessing deglutition (e.g., saliva, normal, and excessive swallows and uninterrupted drinking of water) are presented in detail. SEMG is compared with other techniques in terms of cost, timing, involvement of radiation, etc. Results According to the published data, SEMG of swallowing is a simple and reliable method for screening and preliminary differentiation among dysphagia and odynophagia of various origins. This noninvasive radiation-free examination has a low level of discomfort, and is simple, time-saving and inexpensive to perform. The major weakness of the method seems to be inability for precise diagnostic of neurologically induced dysphagia. Conclusion With standardization of the technique and an established normative database, sEMG might serve as a reliable screening method for optimal patient management but cannot serve for proper investigation of neurogenic dysphagia. PMID:19232090

Hydrous titanium oxide-supported catalysts

International Nuclear Information System (INIS)

Dosch, R.G.; Stohl, F.V.; Richardson, J.T.

1990-01-01

Catalysts were prepared on hydrous titanium oxide (HTO) supports by ion exchange of an active metal for Na + ions incorporated in the HTO support during preparation by reaction with the parent Ti alkoxide. Strong active metal-HTO interactions as a result of the ion exchange reaction can require significantly different conditions for activation as compared to catalysts prepared by more widely used incipient wetness methods. The latter catalysts typically involve conversion or while the HTO catalysts require the alteration of electrostatic bonds between the metal and support with subsequent alteration of the support itself. In this paper, the authors discuss the activation, via sulfidation or reduction, of catalysts consisting of Co, Mo, or Ni-Mo dispersed on HTO supports by ion exchange. Correlations between the activation process and the hydrogenation, hydrodeoxygenation, and hydrodesulfurization activities of the catalysts are presented

Cu(3)(BTC)(2) as a viable heterogeneous solid catalyst for Friedel-Crafts alkylation of indoles with nitroalkenes.

Science.gov (United States)

Nagaraj, Anbu; Amarajothi, Dhakshinamoorthy

2017-05-15

In the present work, Friedel-Crafts alkylation reaction of indole with β-nitrostyrene is examined using a readily available copper based metal-organic frameworks (MOFs) namely, Cu 3 (BTC) 2 (BTC: 1,3,5-benzenetricarboxylic acid) as solid catalyst under mild reaction conditions. Among the various catalysts screened for this reaction, Cu 3 (BTC) 2 exhibits higher activity under the optimized reaction conditions. Besides the absence of leaching of active sites, it is also observed that the catalyst can be reused for four cycles with a minimal decrease in its activity. Cu 3 (BTC) 2 is used as a catalyst to synthesise a series of heterocyclic compounds with different indole and β-nitrostyrene derivatives in moderate to high yields. The present catalytic system shows comparable activity against to recent reports but the advantage of Cu 3 (BTC) 2 is that it does not require any post-functionalization and above all it can be readily synthesised, thus contributing to the synthesis of heterocyclic compounds with high biological interest. Copyright © 2017 Elsevier Inc. All rights reserved.

[Economic evaluation on breast cancer screening in mainland China: a systematic review].

Science.gov (United States)

Wang, L; Shi, J F; Huang, H Y; Zhu, J; Li, J; Fang, Y; Dai, M

2016-12-10

Objective: To gather available evidence related to the economic evaluation on breast cancer screening in mainland China and to provide reference for further research. Methods: A systematic review was conducted to identify articles in PubMed and three Chinese databases (CNKI, Wanfang and VIP) during 1995-2015. Data related to descriptive characteristics, rates on participation and detection for population-based studies, methods for model-based studies, types of economic evaluation and results, were extracted. A Consolidated Health Economic Evaluation Reporting Standards (CHEERS) was used to assess the reporting quality of included studies. Results: Of the 356 records searched in the databases, 13 studies (all published between 2012 and 2015) were included in the current paper involving 11 population-based studies and 3 model-based evaluations (1 study using both methods). Age of the participants who started to be engaged in the screening program ranged from 18 to 45 years old, but terminated at the age of 59 years or older. The screening modalities included single-used clinical breast examination, mammography and ultrasound or combined applications. Study persepectives were described in 7 studies, with 5 from the healthcare providers, and 2 from societal angles. Only 5 studies discounted cost or effectiveness. Out of 11 papers, 9 showed the results on cost-effectiveness analysis (CEA) that reporting the cost per breast cancer detection, with median as 145.0 thousand Chinese Yuan (CNY), ranging from 49.7 thousand to 2 293.0 thousand CNY. From 4 papers with results of cost-utility analysis (CUA), the cost per quality adjusted life year (QALY) gained or cost per disability adjusted life year (DALY) averted, were evaluated. The incremental cost-effectiveness ratio (ICER) was from 2.9 thousand to 270.7 thousand CNY (GDP per capita of China was CNY 49.3 thousand in 2015). In 13 studies, the quality of reporting varied, with an average score of 14.5 (range: 9.5-21.0). In

Evaluating the evidence: direct-to-consumer screening tests advertised online.

Science.gov (United States)

Lovett, Kimberly M; Mackey, Timothy K; Liang, Bryan A

2012-09-01

Unsupervised online direct-to-consumer (DTC) access to medical services has rapidly expanded to medical screening tests, which have not been critically evaluated for their evidence basis. The objective of this study is to identify the scope of online-advertised DTC screening tests, outline the evidence for use of available DTC testing and suggest regulatory reform to address the relevant issues. An observational study of website advertisements, testing services and counselling/follow-up services for DTC testing was conducted. Data were collected from websites between 4 April and 1 June 2011. Each website was assessed for tests offered, advertised indications and availability of counselling/follow-up services. Advertised testing indications were compared with US Preventive Services Task Force recommendations and/or specialty guidelines and categorized as Supported, Against, Insufficient Evidence or No Guidance. Of 20 companies identified as offering DTC screening tests, 95% (19/20) do not clearly offer pretest counselling, post-test counselling and/or test follow-up. One hundred and twenty-seven different tests were identified. Only 19/127 (15%) could be Supported for screening in a target group selected for testing; 38/127 (30%) were given recommendations to avoid use in specific target group(s) selected for testing ('Against recommendations'); 29/127 (23%) had Insufficient Evidence of value, and for 64/127 (50%) No Guidance could be given. Only 4/127 (3%) tests were Supported for general screening use. Virtually all identified medical tests advertised and offered DTC are not recommended for use in screening by evidence-based guidelines. Limited oversight may lead to inaccurate self-diagnosis, treatment and wasted health resources.

Anion-π Catalysts with Axial Chirality.

Science.gov (United States)

Wang, Chao; Matile, Stefan

2017-09-04

The idea of anion-π catalysis is to stabilize anionic transition states by anion-π interactions on aromatic surfaces. For asymmetric anion-π catalysis, π-acidic surfaces have been surrounded with stereogenic centers. This manuscript introduces the first anion-π catalysts that operate with axial chirality. Bifunctional catalysts with tertiary amine bases next to π-acidic naphthalenediimide planes are equipped with a bulky aromatic substituent in the imide position to produce separable atropisomers. The addition of malonic acid half thioesters to enolate acceptors is used for evaluation. In the presence of a chiral axis, the selective acceleration of the disfavored but relevant enolate addition was much better than with point chirality, and enantioselectivity could be observed for the first time for this reaction with small-molecule anion-π catalysts. Enantioselectivity increased with the π acidity of the π surface, whereas the addition of stereogenic centers around the aromatic plane did not cause further improvements. These results identify axial chirality of the active aromatic plane generated by atropisomerism as an attractive strategy for asymmetric anion-π catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methanol conversion to hydrocarbons using modified clinoptilolite catalysts. Investigation of catalyst lifetime and reactivation

Energy Technology Data Exchange (ETDEWEB)

Hutchings, G J; Themistocleous, T; Copperthwaite, R G

1988-10-17

A study of the deactivation and reactivation of modified clinoptilolite catalysts for methanol conversion to hydrocarbons is reported. Clinoptilolite catalysts, modified by either ammonium ion exchange or hydrochloric acid treatment, exhibit a short useful catalyst lifetime for this reaction (ca. 2-3 h) due to a high rate of coke deposition (3-5.10/sup -3/ g carbon/g catalyst/h). A comparative study of reactivation using oxygen, nitrous oxide and ozone/oxygen as oxidants indicated that nitrous oxide reactivation gives improved catalytic performance when compared to the activity and lifetime of the fresh catalyst. Both oxygen and ozone/oxygen were found to be ineffective for the reactivation of clinoptilolite. Initial studies of in situ on-line reactivation are also described. 3 figs., 15 refs., 4 tabs.

Magnetic catalyst bodies

NARCIS (Netherlands)

Teunissen, Wendy; Bol, A.A.; Geus, John W.

1999-01-01

After a discussion about the importance of the size of the catalyst bodies with reactions in the liquid-phase with a suspended catalyst, the possibilities of magnetic separation are dealt with. Deficiencies of the usual ferromagnetic particles are the reactivity and the clustering of the

Study on the poisoning effect-of non-vanadium catalysts by potassium

Science.gov (United States)

Zeng, Huanmu; Liu, Ying; Yu, Xiaowei; Lin, Yasi

2018-02-01

The poisoning effect of catalyst by alkali metals is one of the problems in the selective catalytic reduction (SCR) of NO by NH3. Serious deactivation by alkali poisoning have been proved to take place in the commercial vanadium catalyst. Recently, non-vanadium catalysts such as copper oxides, manganese oxides, chromium oxides and cerium oxides have attracted special attentions in SCR application. However, their tolerance in the presence of alkali metals is still doubtful. In this paper, copper oxides, manganese oxides, chromium oxides and cerium oxides supported on TiO2 nanoparticle was prepared by impregnating method. Potassium nitrate was chosen as the precursor of poisoner. Catalytic activities of these catalysts were evaluated before and after the addition of potassium. Some characterization methods including X-ray diffraction and temperature programmed desorption was utilized to reveal the main reason of alkali deactivation.

How to make Fischer-Tropsch catalyst scale-up fully reliable?

Energy Technology Data Exchange (ETDEWEB)

Fischer, L.; Heraud, J.P.; Forret, A.; Gazarian, J. [IFP Energies nouvelles, Solaize (France); Cornaro, U. [Eni S.p.A., San Donato Milanese (Italy). R and M Div.; Carugati, A. [Eni S.p.A., San Donato Milanese (Italy). E and P Div.

2011-07-01

Several players use Fischer-Tropsch catalysts and technologies industrially [1,2] or declare to be ready for industrial application [e.g. 3]. Present R and D aims to further increase capacities per train [4] or improve catalyst selectivity towards middle distillates [5]. For transforming promising laboratory results into industrial reality, representative catalyst testing is of particular importance for slurry bubble column FT. In the Italian eni's refinery of Sannazzaro, a 20 BPD slurry bubble column pilot plant has cumulated more than 20,000 hours time on stream in different campaigns. Non reactive slurry bubble columns corresponding to reactor capacities between 20 BPD and 1000 BPD permitted to determine the profiles for gas hold up and liquid velocities as a function of gas flow, catalyst loading, reactor diameter and internals. A hydrodynamic model based on those data led to design a Large Validation Tool, which can reproduce under reaction conditions a high mechanical stress on the catalyst equivalent to the one experienced in an industrial 15000 BPD reactor. While those tools have proven to be efficient for developing an industrial scale FT catalyst [3], they predict today in a representative manner fines formation, activity and selectivity of improved catalysts and / or for optimization of operation conditions to increase the capacity per train. We compare the here presented approach to others. We have found that it is mandatory to combine chemical stress from the reaction products with mechanical stress as experienced in an industrial slurry bubble column, in order to evaluate in a reliable way catalyst performance stability and fines formation. The potential of improvements are discussed. (orig.)

Rapid in vivo screening method for the evaluation of new anti ...

African Journals Online (AJOL)

Rapid in vivo screening method for the evaluation of new anti helicobacter ... Six to eight week-old mice pre-treated (7 days) with Amoxicillin/Metronidazole (25 ... These findings were used as a mouse model of Helicobacter pylori infection to ...

Field-based evaluations of horizontal flat-plate fish screens, II: Testing of a unique off-stream channel device - The Farmers Screen

Science.gov (United States)

Mesa, Matthew G.; Rose, Brien P.; Copeland, Elizabeth S.

2012-01-01

Screens are installed at water diversion sites to reduce entrainment of fish. Recently, the Farmers Irrigation District (Oregon) developed a unique flat-plate screen (the “Farmers Screen”) that operates passively and may offer reduced installation and operating costs. To evaluate the effectiveness of this screen on fish, we conducted two separate field experiments. First, juvenile coho salmon Oncorhynchus kisutch were released over a working version of this screen under a range of inflows (0.02–0.42 m3/s) and diversion flows (0.02–0.34 m3/s) at different water depths. Mean approach velocities ranged from 0 to 5 cm/s and sweeping velocities ranged from 36 to 178 cm/s. Water depths over the screen surface ranged from 1 to 25 cm and were directly related to inflow. Passage of fish over the screen under these conditions did not severely injure them or cause delayed mortality, and no fish were observed becoming impinged on the screen surface. Second, juvenile coho salmon and steelhead O. mykiss were released at the upstream end of a 34-m flume and allowed to volitionally move downstream and pass over a 3.5-m section of the Farmers Screen to determine whether fish would refuse to pass over the screen after encountering its leading edge. For coho salmon, 75–95% of the fish passed over the screen within 5 min and 82–98% passed within 20 min, depending on hydraulic conditions. For steelhead, 47–90% of the fish passed over the screen within 5 min and 79–95% passed within 20 min. Our results indicate that when operated within its design criteria, the Farmers Screen provides safe and efficient downstream passage of juvenile salmonids under a variety of hydraulic conditions.

Evaluating two methods of digital photography in retinopathy screening

Directory of Open Access Journals (Sweden)

Li Chen

2018-02-01

Full Text Available AIM:To evaluate the advantages of non-mydriatic fundus photography(NMFCSand mydriatic fundus photography(MFCSas eye-bottom screening and diagnosis methods in compared with gold standard fluorescein fundus angiography(FFA. METHODS: A total of 276 patients which involved in Chronic Diabetes Management Achieves within 4 streets of Pudong District Shanghai, were enrolled for diabetic retinopathy(DRexamination including NMFCS, MFCS and FFA. These DR examinations were proceeded after vision, slit-lamp and dioptroscopy tests, and reported by professionals. For those with suspicious fundus diseases, we would make appointments with specialist for further treatment. RESULTS: A total of 1104 colorful fundus images, and 1056 images(95.65%could be used to analyze. There were 408 appreciable images, 116 basically appreciable images and 28 unusable images in 552 NMFCS images. In addition, there were 432 appreciable images, 100 basically appreciable images and 20 unusable images in 552 MFCS images. There was no significant differences between NMFCS and MFCS(P>0.05. Compared with FFA with DRⅠ as the critical value, the specificity of digital photography for NMFCS was 95.71%, the sensitivity was 93.56%; however, MFCS are 95.43% and 98.02%. There was no statistically significant difference between the two screening methods(P>0.05. Compared with FFA with DRⅡ as the critical value, the specificity of digital photography for NMFCS was 95.35% and the sensitivity was 93.44%; however, for MFCS were 95.81% and 98.36%. There was no statistically significant difference between the two screening methods(P>0.05. CONCLUSION: Both NMFCS and MFCS could be used for the diagnosis and screening for eye diseases. NMFCS is easier and faster for digital photography, which is suitable for mass screening. MFCS is more likely to provide detailed information about the follow-up of the disease.

Evaluation of screening for oral cancer and precancer in a company headquarters.

Science.gov (United States)

Downer, M C; Evans, A W; Hughes Hallet, C M; Jullien, J A; Speight, P M; Zakrzewska, J M

1995-04-01

Oral cancer and precancer appear to fulfil many of the criteria for a disease suitable for mass screening. Several commercial organisations in the UK have introduced screening for their employees. One program has been formally evaluated over the course of 1 yr. Of 553 company headquarters staff aged > or = 40 yr, 292 (53%) responded to the well-publicised screening invitation and received a simple clinical examination of the oral mucosa from one of two company dentists. In addition, 17 staff were screened from a separate company work-site. After screening, subjects were examined independently by an oral medicine specialist with access to the relevant diagnostic aids. The dentists' screening decisions were validated against the specialist's definitive diagnoses (the 'gold standard'). The true prevalence of subjects with lesions diagnosed as positive (white patch, red patch or ulcer of greater than 2 weeks' duration) was 17 (5.5%). Overall, sensitivity was 0.71 and specificity, 0.99. The compliance rate to screening among headquarters subjects in seven occupational categories did not differ significantly from the occupational profile for all headquarters personnel. Estimates of relative risk of a positive diagnosis were calculated by logistic regression for five independent variables; gender, age, moderate smoking, heavy smoking, and smoking combined with greater than low risk alcohol consumption. Only heavy smoking (> or = 20 cigarettes per day) produced a significant odds ratio (3.43, P < 0.05).

Development of GREET Catalyst Module

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

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.

Evaluation of the isotope separation rate of deuterium exchange reaction between H2 and H2O with platinum catalyst

International Nuclear Information System (INIS)

Kitamoto, Asashi; Takashima, Yoichi; Shimizu, Masami.

1983-01-01

The high performance catalysts of hydrophobic carrier with fully dispersed platinum were used to measure the isotope separation performance of hydrogen by the chemical exchange method. The continuous injection of oxygen on the order of 10 3 ppm was effective in regenerating catalyst activity and in maintaining high performance for a long time. The separation performance in a trickle bed column should be evaluated by using two parameters, ksub(g) and ksub(l). These two parameters were unified to the overall transfer coefficient ksub(fg), which may be sufficient in the estimation of overall performance or the design of a separation plant by the chemical exchange method. When one wants to increase the transfer rate in a chemical exchange column, the improvement of ksub(l) rather than ksub(g) may be more effective in increasing the overall transfer rate (its coefficient is expressed by ksub(fg) in this paper). (author)

Catalytic hydrotreatment of fast pyrolysis oil using bimetallic Ni-Cu catalysts on various supports

NARCIS (Netherlands)

Ardiyanti, A. R.; Khromova, S. A.; Venderbosch, R. H.; Yakovlev, V. A.; Melian-Cabrera, I. V.; Heeres, H. J.

2012-01-01

Bimetallic Ni-Cu catalysts on various Supports (CeO2-ZrO2, ZrO2, SiO2, TiO2, rice husk carbon, and Sibunite) with metal contents ranging from 7.5 to 9.0 (Ni) and 3.1-3.6 wt.% (Cu) for the inorganic supports and 17.1-17.8 (Ni) and 7.1-7.8 (Cu) for the carbon supports were synthesised and screened for

Catalytic Hydrodechlorination of Trichlorobenzenes with Pd(PhenCl2 as Catalyst Precursor

Directory of Open Access Journals (Sweden)

Guanlin Zhang

2015-01-01

Full Text Available We reported the catalytic hydrodechlorination (HDC of trichlorobenzenes by an organometallic compound Pd(PhenCl2 as a catalyst precursor. The catalyst precursor was prepared by chemical coordination reaction and characterized by FTIR and 1H NMR techniques. The HDC performance of Pd(PhenCl2 as catalyst precursor was evaluated on 1,2,3-, 1,2,4-, and 1,3,5-trichlorobenzenes (TCBs. All TCBs could be converted to dechlorination products with high conversion. Products distribution was closely related with the substrate structures and C-Cl bond energies. A reasonable reaction mechanism was also proposed.

Visible-Light-Responsive Catalysts Using Quantum Dot-Modified TiO2 for Air and Water Purification

Science.gov (United States)

Coutts, Janelle L.; Hintze, Paul E.; Clausen, Christian; Richards, Jeffrey Todd

2014-01-01

Photocatalysis, the oxidation or reduction of contaminants by light-activated catalysts, utilizing titanium dioxide (TiO2) as the catalytic substrate has been widely studied for trace contaminant control in both air and water applications. The interest in this process is due primarily to its low energy consumption and capacity for catalyst regeneration. Titanium dioxide requires ultraviolet light for activation due to its relatively large band gap energy of 3.2 eV. Traditionally, Hg-vapor fluorescent light sources are used in PCO reactors; however, the use of mercury precludes the use of this PCO technology in a spaceflight environment due to concerns over crew Hg exposure. The development of a visible-light responsive (VLR) TiO2-based catalyst would eliminate the concerns over mercury contamination. Further, VLR development would allow for the use of ambient visible solar radiation or highly efficient LEDs, both of which would make PCO approaches more efficient, flexible, economical, and safe. Though VLR catalyst development has been an active area of research for the past two decades, there are few commercially available VLR catalysts. Those VLR catalysts that are commercially available do not have adequate catalytic activity, in the visible region, to make them competitive with those operating under UV irradiation. This study was initiated to develop more effective VLR catalysts through a novel method in which quantum dots (QD) consisting of narrow band gap semiconductors (e.g., CdS, CdSe, PbS, ZnSe, etc.) are coupled to TiO2 via two preparation methods: 1) photodeposition and 2) mechanical alloying using a high-speed ball mill. A library of catalysts was developed and screened for gas and aqueous phase applications using ethanol and 4-chlorophenol as the target contaminants, respectively. Both target compounds are well studied in photocatalytic systems and served as model contaminants for this research. Synthesized catalysts were compared in terms of

Ni catalysts with different promoters supported on zeolite for dry reforming of methane

KAUST Repository

Alotaibi, Raja; Alenazey, Feraih; Alotaibi, Faisal; Wei, Nini; Al-Fatesh, Ahmed; Fakeeha, Anis

2015-01-01

Dry reforming of methane (DRM) is considered a high endothermic reaction with operating temperatures between 700 and 1000 °C to achieve high equilibrium conversion of CH4 and CO2 to the syngas (H2 and CO). The conventional catalysts used for DRM are Ni-based catalysts. However, many of these catalysts suffer from the short longevity due to carbon deposition. This study aims to evaluate the effect of La and Ca as promoters for Ni-based catalysts supported on two different zeolite supports, ZL (A) (BET surface area = 925 m2/g, SiO2/Al2O3 mol ratio = 5.1), and ZL (B) (BET surface area = 730 m2/g, SiO2/Al2O3 mol ratio = 12), for DRM. The physicochemical properties of the prepared catalysts were characterized with XRD, BET, TEM and TGA. These catalysts were tested for DRM in a microtubular reactor at reaction conditions of 700 °C. The catalyst activity results show that the catalysts Ni/ZL (B) and Ca-Ni/ZL (B) give the highest methane conversion (60 %) with less time on stream stability compared with promoted Ni on ZL (A). In contrast, La-containing catalysts, La-Ni/ZL (B), show more time on stream stability with minimum carbon content for the spent catalyst indicating the enhancement of the promoters to the Ni/ZL (A) and (B), but with less catalytic activity performance in terms of methane and carbon dioxide conversions due to rapid catalyst deactivation.

Ni catalysts with different promoters supported on zeolite for dry reforming of methane

KAUST Repository

Alotaibi, Raja

2015-07-08

Dry reforming of methane (DRM) is considered a high endothermic reaction with operating temperatures between 700 and 1000 °C to achieve high equilibrium conversion of CH4 and CO2 to the syngas (H2 and CO). The conventional catalysts used for DRM are Ni-based catalysts. However, many of these catalysts suffer from the short longevity due to carbon deposition. This study aims to evaluate the effect of La and Ca as promoters for Ni-based catalysts supported on two different zeolite supports, ZL (A) (BET surface area = 925 m2/g, SiO2/Al2O3 mol ratio = 5.1), and ZL (B) (BET surface area = 730 m2/g, SiO2/Al2O3 mol ratio = 12), for DRM. The physicochemical properties of the prepared catalysts were characterized with XRD, BET, TEM and TGA. These catalysts were tested for DRM in a microtubular reactor at reaction conditions of 700 °C. The catalyst activity results show that the catalysts Ni/ZL (B) and Ca-Ni/ZL (B) give the highest methane conversion (60 %) with less time on stream stability compared with promoted Ni on ZL (A). In contrast, La-containing catalysts, La-Ni/ZL (B), show more time on stream stability with minimum carbon content for the spent catalyst indicating the enhancement of the promoters to the Ni/ZL (A) and (B), but with less catalytic activity performance in terms of methane and carbon dioxide conversions due to rapid catalyst deactivation.

Fischer-Tropsch Synthesis over Iron Manganese Catalysts: Effect of Preparation and Operating Conditions on Catalyst Performance

Directory of Open Access Journals (Sweden)

Ali A. Mirzaei

2009-01-01

molar basis which is the most active catalyst for the conversion of synthesis gas to light olefins. The effects of different promoters and supports with loading of optimum support on the catalytic performance of catalysts are also studied. It was found that the catalyst containing 50%Fe/50%Mn/5 wt.%Al2O3 is an optimum-modified catalyst. The catalytic performance of optimal catalyst has been studied in operation conditions such as a range of reaction temperatures, H2/CO molar feed ratios and a range of total pressures. Characterization of both precursors and calcined catalysts is carried out by powder X-ray diffraction (XRD, scanning electron microscopy (SEM, BET specific surface area and thermal analysis methods such as TGA and DSC.

Hydrophobic catalyst applications in the nuclear field and in environmental studies

International Nuclear Information System (INIS)

Ionita, Gheorghe; Popescu, Irina; Stefanescu, Ioan; Varlam, Carmen

2002-01-01

The paper presents methods of preparation and applications of hydrophobic platinum catalysts in nuclear field and environmental protection. These catalysts allow the transport of gaseous reactants and reaction products to and from catalytic active centers since the pore blocking by water is avoided. Hence the activity and stability of the catalysts increase and isotopic exchange columns with simpler internal structure can be achieved. The aim of the paper is: 1. to give a data base regarding the preparation methods of the optimal catalyst type; 2. to indicate the utilization and operation procedures of hydrophobic catalysts with mixed and simple packings; 3. to evaluate the performances and applications of hydrophobic catalysts. Over one hundred of hydrophobic catalysts of the active metal/support type were prepared in our laboratory. Hydrophobic features were obtained by different methods like these: - coating a hydrophilic conventional catalyst with a hydrophobic agent such as silicone or teflon; - supporting the active metal directly into the pores of a hydrophobic support; - mixing the teflon powder with a hydrophilic conventional catalyst; coating the support with teflon followed by the impregnation with the precursor of the active metal. The most important application of these catalysts is detritiation of the heavy water used as moderator and coolant in CANDU type reactors. Build-up of tritium in heavy water following the neutron capture by deuterium leads to a reduction in the moderating properties and at the same time leads to a contamination hazard for both operation personnel and environment. Tritium recovery leads this way to both improving the moderating qualities of the heavy water and obtaining valuable pure tritium of high importance in fusion research and other laboratory studies. One gram of tritium costs about USD 10,000. The physical chemical process is water-hydrogen catalyzed isotopic exchange. Also discussed in the paper is the separation of

Deactivation and regeneration of refinery catalysts

Energy Technology Data Exchange (ETDEWEB)

Furimsky, E.

1979-08-01

A discussion covers the mechanisms of catalyst aging, poisoning, coke deposition, and metals deposition; feedstock pretreatment to extend catalyst life; the effects of operating conditions; the effects of catalyst composition and structure on its stability; nonchemical deactivation processes; and methods of catalyst regeneration, including coke burn-off and solvent extraction.

Different catalysts for new polyols for rigid PUR-PIR foams

Directory of Open Access Journals (Sweden)

Liszkowska Joanna

2015-12-01

Full Text Available New polyols were synthesized with 2-hydroxypropane-1.2.3-tricarboxylic acid and butane-1,4-diol (1.4-BD. The synthesis was performed using different catalysts in the amount of 0.1%. Used catalyst: Tyzor TPT, tin(II acetate, sulfuric(IV acid. The fourth reaction was conducted without the use of a catalyst. The polyols’ properties were evaluated with regards to the usefulness in rigid polyurethane-polyisocyanurate (PUR-PIR foams (acid value, density, pH and solubility, FTIR spectra. Based on the research, it was evaluated that only the polyol synthesized using Tyzor TPT (E6 was useful in production of rigid PUR-PIR foams. Its hydroxyl number was 496 mgKOH/g and its viscosity was about 14 552 mPa · s. A series of five foams P6.1–P6.5 was produced with this polyol. Rigid foams test results indicated that the amount of this compound in the foam substantially affects its compressive strength, density and their retention. The foams have low brittleness values.

The effect of noble metals on catalytic methanation reaction over supported Mn/Ni oxide based catalysts

Directory of Open Access Journals (Sweden)

Wan Azelee Wan Abu Bakar

2015-09-01

Full Text Available Carbon dioxide (CO2 in sour natural gas can be removed using green technology via catalytic methanation reaction by converting CO2 to methane (CH4 gas. Using waste to wealth concept, production of CH4 would increase as well as creating environmental friendly approach for the purification of natural gas. In this research, a series of alumina supported manganese–nickel oxide based catalysts doped with noble metals such as ruthenium and palladium were prepared by wetness impregnation method. The prepared catalysts were run catalytic screening process using in-house built micro reactor coupled with Fourier Transform Infra Red (FTIR spectroscopy to study the percentage CO2 conversion and CH4 formation analyzed by GC. Ru/Mn/Ni(5:35:60/Al2O3 calcined at 1000 °C was found to be the potential catalyst which gave 99.74% of CO2 conversion and 72.36% of CH4 formation at 400 °C reaction temperature. XRD diffractogram illustrated that the supported catalyst was in polycrystalline with some amorphous state at 1000 °C calcination temperature with the presence of NiO as active site. According to FESEM micrographs, both fresh and used catalysts displayed spherical shape with small particle sizes in agglomerated and aggregated mixture. Nitrogen Adsorption analysis revealed that both catalysts were in mesoporous structures with BET surface area in the range of 46–60 m2/g. All the impurities have been removed at 1000 °C calcination temperature as presented by FTIR, TGA–DTA and EDX data.

Implementation and process evaluation of a workplace colorectal cancer screening program in eastern Washington.

Science.gov (United States)

Hannon, Peggy A; Vu, Thuy; Ogdon, Sara; Fleury, Emily M; Yette, Emily; Wittenberg, Reva; Celedonia, Megan; Bowen, Deborah J

2013-03-01

Colorectal cancer screening is a life-saving intervention, but screening rates are low. The authors implemented and evaluated the Spokane Colorectal Cancer Screening Program-a novel worksite intervention to promote colorectal cancer screening that used a combination of evidence-based strategies recommended by the Guide to Community Preventive Services, as well as additional strategies. Over a period of approximately 3 months, participating worksites held one or more physician-led seminars about colorectal cancer screening for employees. They also distributed free fecal immunochemical tests at the worksite to employees 50 years and older, and they provided test results to employees and their primary care physician. The authors measured attendance at seminars, test kits taken and returned, employee awareness of the program, and colorectal cancer screening rates in participating and comparison worksites. It is estimated that 9% of eligible employees received kits at the worksite, and 4% were screened with these kits. The Spokane Colorectal Cancer Screening Program was a promising pilot test of an innovative worksite screening program that successfully translated evidence-based strategies into practical use in a brief period of time, and it merits a larger study to be able to test its effects more rigorously.

Women’s perspectives and experiences on screening for osteoporosis (Risk-stratified Osteoporosis Strategy Evaluation, ROSE)

DEFF Research Database (Denmark)

Rothmann, Mette Juel; Huniche, Lotte; Ammentorp, Jette

2014-01-01

main themes: knowledge about osteoporosis, psychological aspects of screening, and moral duty. The women viewed the program in the context of their everyday life and life trajectories. Age, lifestyle, and knowledge about osteoporosis were important to how women ascribed meaning to the program, how......This study aimed to investigate women's perspectives and experiences with screening for osteoporosis. Focus groups and individual interviews were conducted. Three main themes emerged: knowledge about osteoporosis, psychological aspects of screening, and moral duty. Generally, screening was accepted...... due to life experiences, self-perceived risk, and the preventive nature of screening. PURPOSE: The risk-stratified osteoporosis strategy evaluation (ROSE) study is a randomized prospective population-based trial investigating the efficacy of a screening program to prevent fractures in women aged 65...

Ozone Decomposition on the Surface of Metal Oxide Catalyst

Directory of Open Access Journals (Sweden)

Batakliev Todor Todorov

2014-12-01

Full Text Available The catalytic decomposition of ozone to molecular oxygen over catalytic mixture containing manganese, copper and nickel oxides was investigated in the present work. The catalytic activity was evaluated on the basis of the decomposition coefficient which is proportional to ozone decomposition rate, and it has been already used in other studies for catalytic activity estimation. The reaction was studied in the presence of thermally modified catalytic samples operating at different temperatures and ozone flow rates. The catalyst changes were followed by kinetic methods, surface measurements, temperature programmed reduction and IR-spectroscopy. The phase composition of the metal oxide catalyst was determined by X-ray diffraction. The catalyst mixture has shown high activity in ozone decomposition at wet and dry O3/O2 gas mixtures. The mechanism of catalytic ozone degradation was suggested.

Morphological effect of BiVO4 catalysts on degradation of aqueous paracetamol under visible light irradiation.

Science.gov (United States)

Hu, Changying; Xu, Jie; Zhu, Yaqi; Chen, Acong; Bian, Zhaoyong; Wang, Hui

2016-09-01

Morphological effect of bismuth vanadate (BiVO4) on visible light-driven catalytic degradation of aqueous paracetamol was carefully investigated using four monoclinic BiVO4 catalysts. The catalysts with different morphologies were controllably prepared by a hydrothermal method without any additions. The prepared catalysts were fully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis diffuse reflectance spectroscopy (DRS). Under the visible light irradiation, these catalysts with different morphology were investigated to degrade aqueous paracetamol contaminant. The degradation effects were evaluated based on the catalyst morphology, solution pH, initial paracetamol concentration, and catalyst dosage. Cube-like BiVO4 powders exhibited excellent photocatalytic performance. The optimal photocatalytic performance of the cube-like BiVO4 in degrading paracetamol was achieved.

Autothermal reforming catalyst having perovskite structure

Science.gov (United States)

Krumpel, Michael [Naperville, IL; Liu, Di-Jia [Naperville, IL

2009-03-24

The invention addressed two critical issues in fuel processing for fuel cell application, i.e. catalyst cost and operating stability. The existing state-of-the-art fuel reforming catalyst uses Rh and platinum supported over refractory oxide which add significant cost to the fuel cell system. Supported metals agglomerate under elevated temperature during reforming and decrease the catalyst activity. The catalyst is a perovskite oxide or a Ruddlesden-Popper type oxide containing rare-earth elements, catalytically active firs row transition metal elements, and stabilizing elements, such that the catalyst is a single phase in high temperature oxidizing conditions and maintains a primarily perovskite or Ruddlesden-Popper structure under high temperature reducing conditions. The catalyst can also contain alkaline earth dopants, which enhance the catalytic activity of the catalyst, but do not compromise the stability of the perovskite structure.

Isotope exchange in oxide-containing catalyst

Science.gov (United States)

Brown, Kenneth G. (Inventor); Upchurch, Billy T. (Inventor); Hess, Robert V. (Inventor); Miller, Irvin M. (Inventor); Schryer, David R. (Inventor); Sidney, Barry D. (Inventor); Wood, George M. (Inventor); Hoyt, Ronald F. (Inventor)

1989-01-01

A method of exchanging rare-isotope oxygen for common-isotope oxygen in the top several layers of an oxide-containing catalyst is disclosed. A sample of an oxide-containing catalyst is exposed to a flowing stream of reducing gas in an inert carrier gas at a temperature suitable for the removal of the reactive common-isotope oxygen atoms from the surface layer or layers of the catalyst without damaging the catalyst structure. The reduction temperature must be higher than any at which the catalyst will subsequently operate. Sufficient reducing gas is used to allow removal of all the reactive common-isotope oxygen atoms in the top several layers of the catalyst. The catalyst is then reoxidized with the desired rare-isotope oxygen in sufficient quantity to replace all of the common-isotope oxygen that was removed.

Shape-selective catalysts for Fischer-Tropsch chemistry. Final report: January 1, 2001 - December 31, 2008

International Nuclear Information System (INIS)

Cronauer, D.C.

2011-01-01

Argonne National Laboratory carried 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 was desirable that the catalysts have high selectivity and stability with respect to both mechanical strength and aging properties. It was desired that selectivity be directed toward producing diesel fraction components and avoiding excess yields of both light hydrocarbons and heavy waxes. The original goal was to produce shape-selective catalysts that had the potential to limit the formation of long-chain products and yet retain the active metal sites in a protected 'cage.' This cage would also restrict 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. Such catalysts were prepared with silica-containing fractal cages. The activity and strength was essentially the same as that of catalysts without the cages. Since there was no improvement, the program plan was modified as discussed below. A second experimental stage was undertaken to prepare and evaluate active FT catalysts formed by atomic-layer deposition [ALD] of active components on supported membranes and particulate supports. The concept was that of depositing active metals (i.e. ruthenium, iron or cobalt) upon membranes with well defined flow channels of small diameter and length such that the catalytic activity and product molecular weight distribution could be controlled. In order to rapidly evaluate the catalytic membranes, the ALD coating processes were performed in an 'exploratory mode' in which ALD procedures from the literature appropriate for coating flat surfaces were applied to the high surface area membranes. Consequently, the Fe and Ru loadings in the membranes were likely to be smaller than those expected for

An economic evaluation of colorectal cancer screening in primary care practice.

Science.gov (United States)

Meenan, Richard T; Anderson, Melissa L; Chubak, Jessica; Vernon, Sally W; Fuller, Sharon; Wang, Ching-Yun; Green, Beverly B

2015-06-01

Recent colorectal cancer screening studies focus on optimizing adherence. This study evaluated the cost effectiveness of interventions using electronic health records (EHRs); automated mailings; and stepped support increases to improve 2-year colorectal cancer screening adherence. Analyses were based on a parallel-design, randomized trial in which three stepped interventions (EHR-linked mailings ["automated"]; automated plus telephone assistance ["assisted"]; or automated and assisted plus nurse navigation to testing completion or refusal [navigated"]) were compared to usual care. Data were from August 2008 to November 2011, with analyses performed during 2012-2013. Implementation resources were micro-costed; research and registry development costs were excluded. Incremental cost-effectiveness ratios (ICERs) were based on number of participants current for screening per guidelines over 2 years. Bootstrapping examined robustness of results. Intervention delivery cost per participant current for screening ranged from $21 (automated) to $27 (navigated). Inclusion of induced testing costs (e.g., screening colonoscopy) lowered expenditures for automated (ICER=-$159) and assisted (ICER=-$36) relative to usual care over 2 years. Savings arose from increased fecal occult blood testing, substituting for more expensive colonoscopies in usual care. Results were broadly consistent across demographic subgroups. More intensive interventions were consistently likely to be cost effective relative to less intensive interventions, with willingness to pay values of $600-$1,200 for an additional person current for screening yielding ≥80% probability of cost effectiveness. Two-year cost effectiveness of a stepped approach to colorectal cancer screening promotion based on EHR data is indicated, but longer-term cost effectiveness requires further study. Copyright © 2015 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Nanoparticular metal oxide/anatase catalysts

DEFF Research Database (Denmark)

2010-01-01

The present invention concerns a method of preparation of nanoparticular metal oxide catalysts having a narrow particle size distribution. In particular, the invention concerns preparation of nanoparticular metal oxide catalyst precursors comprising combustible crystallization seeds upon which...... the catalyst metai oxide is co-precipitated with the carrier metal oxide, which crystallization seeds are removed by combustion in a final calcining step. The present invention also concerns processes wherein the nanoparticular metal oxide catalysts of the invention are used, such as SCR (deNOx) reactions...

One-step production of long-chain hydrocarbons from waste-biomass-derived chemicals using bi-functional heterogeneous catalysts.

Science.gov (United States)

Wen, Cun; Barrow, Elizabeth; Hattrick-Simpers, Jason; Lauterbach, Jochen

2014-02-21

In this study, we demonstrate the production of long-chain hydrocarbons (C8+) from 2-methylfuran (2MF) and butanal in a single step reactive process by utilizing a bi-functional catalyst with both acid and metallic sites. Our approach utilizes a solid acid for the hydroalkylation function and as a support as well as a transition metal as hydrodeoxygenation catalyst. A series of solid acids was screened, among which MCM-41 demonstrated the best combination of activity and stability. Platinum nanoparticles were then incorporated into the MCM-41. The Pt/MCM-41 catalyst showed 96% yield for C8+ hydrocarbons and the catalytic performance was stable over four reaction cycles of 20 hour each. The reaction pathways for the production of long-chain hydrocarbons is probed with a combination of infrared spectroscopy and steady-state reaction experiments. It is proposed that 2MF and butanal go through hydroalkylation first on the acid site followed by hydrodeoxygenation to produce the hydrocarbon fuels.

Development and Evaluation of Algorithms for Breath Alcohol Screening.

Science.gov (United States)

Ljungblad, Jonas; Hök, Bertil; Ekström, Mikael

2016-04-01

Breath alcohol screening is important for traffic safety, access control and other areas of health promotion. A family of sensor devices useful for these purposes is being developed and evaluated. This paper is focusing on algorithms for the determination of breath alcohol concentration in diluted breath samples using carbon dioxide to compensate for the dilution. The examined algorithms make use of signal averaging, weighting and personalization to reduce estimation errors. Evaluation has been performed by using data from a previously conducted human study. It is concluded that these features in combination will significantly reduce the random error compared to the signal averaging algorithm taken alone.

Oxygen-reducing catalyst layer

Science.gov (United States)

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.

Visible-Light-Responsive Catalyst Development for Volatile Organic Carbon Remediation Project

Science.gov (United States)

Zeitlin, Nancy; Hintze, Paul E.; Coutts, Janelle

2015-01-01

Photocatalysis is a process in which light energy is used to 'activate' oxidation/reduction reactions. Unmodified titanium dioxide (TiO2), a common photocatalyst, requires high-energy UV light for activation due to its large band gap (3.2 eV). Modification of TiO2 can reduce this band gap, leading to visible-light-responsive (VLR) photocatalysts. These catalysts can utilize solar and/or visible wavelength LED lamps as an activation source, replacing mercury-containing UV lamps, to create a "greener," more energy-efficient means for air and water revitalization. Recently, KSC developed several VLR catalysts that, on preliminary evaluation, possessed high catalytic activity within the visible spectrum; these samples out-performed existing commercial VLR catalysts.

Dry reforming of methane in the presence of ruthenium-based catalysts

International Nuclear Information System (INIS)

Safariamin, M.; Tidahy, L.H.; Abi-Aad, E.; Siffert, St.; Aboukais, A.

2009-01-01

The catalytic activities of ruthenium-based catalysts (5 wt% Ru) supported on alumina, ceria and ceria/alumina with different proportions of ceria (nCe 10 Al, n = 1, 3, 5; n = atomic ratio) were studied for the methane reforming reaction with CO 2 (CH 4 / CO 2 = 1) in the temperature range of 400-800 C. Evaluation of coke deposited after the reaction showed carbon deposition on Ru catalysts supported on CeO 2 , 1Ce 10 Al and 3Ce 10 Al, but not on Ru/Al 2 O 3 and Ru/5Ce 10 Al. Moreover, the sample Ru/5Ce 10 Al exhibited a higher activity than the other catalysts. (authors)

Pd enhanced WC catalyst to promote heterogeneous methane combustion

International Nuclear Information System (INIS)

Terracciano, Anthony Carmine; De Oliveira, Samuel; Siddhanti, Deepti; Blair, Richard; Vasu, Subith S.; Orlovskaya, Nina

2017-01-01

Highlights: • Pd enhanced WC catalyst particles were synthesized via mechanochemical alloying. • Catalyst was characterized by XRD, XRF, SEM, and EDS. • Catalyst was deposited on porous ZrO_2 and evaluated in heterogeneous combustion. • During combustion temperature profiles and spectral emissions were collected. - Abstract: The efficiency of combustion for low cost heat production could be greatly enhanced if an active and low cost catalyst would be used to facilitate the chemical reactions occurring during combustor operation. Within this work an experimental study of palladium (Pd) enhanced tungsten carbide (WC) catalyst, synthesized via high energy ball milling and deposited by dip coating onto a magnesia partially stabilized zirconia (MgO-ZrO_2) porous matrix of 10 ppin was evaluated in heterogeneous methane combustion. The synthesized powder was characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS) analysis, as well as by X-ray Fluorescence (XRF); and the morphology of the deposited WC-Pd coating was also characterized using SEM and EDS. Performance evaluation of the heterogeneous combustor with WC-Pd coated MgO-ZrO_2 porous media was conducted at constant air flow rate and various equivalence ratios of methane/air gaseous mixtures, while monitoring axial temperature profiles within the combustion chamber using thermocouples, as well as thermal radiative and acoustic emissions from the combustor exhaust using an externally placed CCD camera and a microphone. It was found that there is a strong dependence of flame position and maximum temperature on equivalence ratio (φ) over the range of 0.47 ± 0.02 ⩽ φ ⩽ 0.75 ± 0.02. Additionally it was found that over the same equivalence ratio range, there is a characteristic 4 peak acoustic signature between 200 and 500 Hz. It was found that at higher equivalence ratios 0.51 ± 0.02 ⩽ φ ⩽ 0.75 ± 0.02 the performance of combustor

Ethanolysis conversion of spent frying oils over aluminium, calcium-phosphate based bi-functional formulated catalysts. Catalytic activity assessment study

Energy Technology Data Exchange (ETDEWEB)

Al-Zaini, Essam O.; Chesterfield, Dean; Adesina, Adesoji A. [The Univ. of New South Wales, Sydney (Australia). Reactor Engineering and Technology Group; Olsen, John [The Univ. of New South Wales, Sydney (Australia). School of Mechanical and Manufacturing Engineering

2013-06-01

The current study compares the catalytic performance of two bi-functional solid catalysts for the transesterification of waste cooking vegetable oil in presence of bio-ethanol acyl-acceptor. The two catalysts were aluminum oxide and seashell-derived calcium oxide supported K{sub 3}PO{sub 4}. The catalytic activity of the produced catalyst samples were assessed and evaluated in terms of their textural and surface chemical properties. Evaluative runs showed that increased amounts of K{sub 3}PO{sub 4} have differently controlled the textural and surface chemical property of the finally synthesised catalyst samples. The behaviour revealed a strong correlation between the percentage yield of ethyl esters EEY% and acid-base site density and strength between the two types of catalysts. Possible leaching test of the catalysts was also used as a measure of performance and as a result, the optimum catalyst, on the basis of both ester yield and resistance to leaching was identified as the sample containing between 10 and 15wt% of K{sub 3}PO{sub 4} on AlO{sub 3} and CaO respectively. (orig.)

Effect of the dispersants on Pd species and catalytic activity of supported palladium catalyst

Energy Technology Data Exchange (ETDEWEB)

Hu, Yue [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); Yang, Xiaojun, E-mail: 10100201@wit.edu.cn [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); Cao, Shuo, E-mail: cao23@email.sc.edu [North America R& D Center, Clariant BU Catalysts, Louisville, 40209, KY (United States); Zhou, Jie [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); Wu, Yuanxin [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Han, Jinyu [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Yan, Zhiguo [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); Zheng, Mingming [Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Hubei Key Laboratory of Oilcrops Lipid Chemistry and Nutrition, Wuhan 430062 (China)

2017-04-01

Highlights: • Polyvinyl alcohol (PVA) inhibited the sintering and reduction of Pd nanoparticles. • Activity was improved for supported Pd catalysts with PVA modified method. • PVA modified method minimized the catalyst deactivation. • This work provides an insight of the regeneration strategies for Pd catalysts. - Abstract: A series of supported palladium catalysts has been prepared through the precipitation method and the reduction method, using polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) as dispersants. The effects of the dispersants on the properties of catalysts were evaluated and the catalytic performance of the new materials was investigated for the oxidative carbonylation of phenol to diphenyl carbonate (DPC). The catalysts as prepared were also characterized by the X-ray diffraction (XRD), transmission electron microscope (TEM), Brunner-Emmet-Teller (BET) measurements and X-ray photoelectron spectroscopy (XPS) techniques. The results show that the addition of the dispersants had no effect on the crystal phase of the catalysts. However, the dispersion of Pd particles was improved when the dispersants were used. Moreover, the particle sizes of Pd nanoparticles modified by PVA were smaller than those modified by PVP. The catalysts prepared using the dispersants gave better yields of DPC than the catalysts prepared without the dispersants. The highest yield of DPC was 17.9% with the PVA-Red catalyst. The characterization results for the used catalysts showed that the Pd species in the PVA-Red catalyst remained mostly divalent and the lattice oxygen species were consumed during the reaction, which could lead to the higher catalytic activity of the PVA-Red catalyst. The experimental results confirm that PVA effectively inhibited the sintering and reduction of active Pd species in the oxidative carbonylation of phenol.

Rapid and Efficient Collection of Platinum from Karstedt's Catalyst Solution via Ligands-Exchange-Induced Assembly.

Science.gov (United States)

Yang, Gonghua; Wei, Yanlong; Huang, Zhenzhu; Hu, Jiwen; Liu, Guojun; Ou, Ming; Lin, Shudong; Tu, Yuanyuan

2018-02-21

Reported herein is a novel strategy for the rapid and efficient collection of platinum from Karstedt's catalyst solution. By taking advantage of a ligand-exchange reaction between alkynols and the 1,3-divinyltetramethyldisiloxane ligand (M Vi M Vi ) that coordinated with platinum (Pt(0)), the Karstedt's catalyst particles with a size of approximately 2.5 ± 0.7 nm could be reconstructed and assembled into larger particles with a size of 150 ± 35 nm due to the hydrogen bonding between the hydroxyl groups of the alkynol. In addition, because the silicone-soluble M Vi M Vi ligand of the Karstedt's catalyst was replaced by water-soluble alkynol ligands, the resultant large particles were readily dispersed in water, resulting in rapid, efficient, and complete collection of platinum from the Karstedt's catalyst solutions with platinum concentrations in the range from ∼20 000 to 0.05 ppm. Our current strategy not only was used for the rapid and efficient collection of platinum from the Karstedt's catalyst solutions, but it also enabled the precise evaluation of the platinum content in the Karstedt's catalysts, even if this platinum content was extremely low (i.e., 0.05 ppm). Moreover, these platinum specimens that were efficiently collected from the Karstedt's catalyst solutions could be directly used for the evaluation of platinum without the need for pretreatment processes, such as calcination and digestion with hydrofluoric acid, that were traditionally used prior to testing via inductively coupled plasma mass spectrometry in conventional methods.

Metal catalysts fight back

OpenAIRE

George Marsh

1998-01-01

In recent years organometallic catalysts, especially metallocenes, have been a major focus of attention in terms of polymerisation chemistry. But the news earlier this year of a family of iron-based catalysts able to rival the effectiveness of both conventional and metallocene catalysts in the polymerisation of ethylene has excited the plastics industry. Because of the impact of this discovery and its potential as a route to lower-priced commodity plastics in the future, it may be useful at t...

Suitability of some promising soot combustion catalysts for application in diesel exhaust treatment

Energy Technology Data Exchange (ETDEWEB)

Badini, Claudio; Saracco, Guido; Serra, Valentina; Specchia, Vito [Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi, 24-10129 Torino (Italy)

1998-09-21

In this work, the effect of thermal treatment at 380C and 600C, under gaseous atmospheres containing some typical components of diesel emissions (SO{sub 2} and water), was studied on some promising catalysts for diesel particulate combustion. In particular, the ageing behaviour of two novel catalysts (based on CsVO{sub 3}+KCl and KVO{sub 3}+KCl, respectively) and of a more widely studied Cu-K-V-Cl catalyst was investigated. The catalytic activities of these novel catalysts were lower than that of the Cu-K-V-Cl one, but, contrary to this last counterpart, they almost completely maintained their activity during ageing treatments in dry or humid air at 380C and 600C, respectively. Moreover, after prolonged thermal exposure in wet air, the activity of the Cu-K-V-Cl catalyst became comparable with that of the CsVO{sub 3}+KCl one, while remaining still slightly higher than that of the KVO{sub 3}+KCl catalyst. The thermal treatments of all the catalysts under investigation in an atmosphere containing SO{sub 2} did not cause an activity decrease. X-ray diffraction analyses showed the formation of new phases (sulphates and vanadates with a K/V ratio different from that of metavanadates) which could also improve the catalytic activity, counterbalancing the loss of active components due to evaporation at high temperatures. Furthermore, the catalyst activity was evaluated after employing repeatedly these catalysts in carbon combustion. The catalytic activities were generally slightly lowered by the repeated use, even though, from this viewpoint, that of Cu-K-V-Cl was more affected than those of the other catalysts. On the basis of the obtained results the CsVO{sub 3}+KCl catalyst was found to allow the best compromise between satisfactory catalyst activity and stability

Improved Catalysts for Heavy Oil Upgrading Based on Zeolite Y Nanoparticles Encapsulated Stable Nanoporous Host

Energy Technology Data Exchange (ETDEWEB)

Conrad Ingram; Mark Mitchell

2007-03-31

The addition of hydrothermally-aged zeolite Y precursor to an SBA-15 synthesis mixture under a mildly acidic condition resulted in the formation of a mesoporous aluminosilicate catalyst, AlSBA-15. The Al-SBA-15 mesoporous catalyst contains strong Br{umlt o}nsted acid sites and aluminum (Al) stabilized in a totally tetrahedral coordination. The physicochemical characteristics of the catalyst varied as a function of the synthesis conditions. The catalyst possessed surface areas ranging between 690 and 850 m{sup 2}/g, pore sizes ranging from 5.6 to 7.5 nm, and pore volumes up 1.03 cm{sup 3}, which were comparable to the parent SBA-15 synthesized under similar conditions. Two wt % Al was present in the catalyst that was obtained from the reaction mixture that contained the highest Al content. The Al remained stable in totally tetrahedral coordination after calcination at a temperature of 550 C. The Al-SBA-15 mesoporous catalyst showed significant catalytic activity for cumene dealkylation, and the activity increased as the amount of zeolite precursor added to the SBA-15 mixture was increased. In preparation for the final phase of the project, the catalyst was embedded into a psuedoboemite alumina (catapal B) matrix and then formed into pellets. In the final phase of the project, the pelletized catalyst is being evaluated for the conversion of a heavy petroleum feedstock to naphtha and middle distillates. This phase was significantly delayed during the past six months due to a serious malfunction of the fume hoods in the Clark Atlanta University's Research Center for Science and Technology, where the project is being conducted. The fume hood system was repaired and the catalyst evaluation is now underway.

Development of Non-Noble Metal Ni-Based Catalysts for Dehydrogenation of Methylcyclohexane

KAUST Repository

Al-ShaikhAli, Anaam H.

2016-11-30

Liquid organic chemical hydride is a promising candidate for hydrogen storage and transport. Methylcyclohexane (MCH) to toluene (TOL) cycle has been considered as one of the feasible hydrogen carrier systems, but selective dehydrogenation of MCH to TOL has only been achieved using the noble Pt-based catalysts. The aim of this study is to develop non-noble, cost-effective metal catalysts that can show excellent catalytic performance, mainly maintaining high TOL selectivity achievable by Pt based catalysts. Mono-metallic Ni based catalyst is a well-known dehydrogenation catalyst, but the major drawback with Ni is its hydrogenolysis activity to cleave C-C bonds, which leads to inferior selectivity towards dehydrogenation of MCH to TOL. This study elucidate addition of the second metal to Ni based catalyst to improve the TOL selectivity. Herein, ubiquitous bi-metallic nanoparticles catalysts were investigated including (Ni–M, M: Ag, Zn, Sn or In) based catalysts. Among the catalysts investigated, the high TOL selectivity (> 99%) at low conversions was achieved effectively using the supported NiZn catalyst under flow of excess H2. In this work, a combined study of experimental and computational approaches was conducted to determine the main role of Zn over Ni based catalyst in promoting the TOL selectivity. A kinetic study using mono- and bimetallic Ni based catalysts was conducted to elucidate reaction mechanism and site requirement for MCH dehydrogenation reaction. The impact of different reaction conditions (feed compositions, temperature, space velocity and stability) and catalyst properties were evaluated. This study elucidates a distinctive mechanism of MCH dehydrogenation to TOL reaction over the Ni-based catalysts. Distinctive from Pt catalyst, a nearly positive half order with respect to H2 pressure was obtained for mono- and bi-metallic Ni based catalysts. This kinetic data was consistent with rate determining step as (somewhat paradoxically) hydrogenation

Rejuvenation of the SCR catalyst at Mehrum

Energy Technology Data Exchange (ETDEWEB)

Nagai, Y.; Inatsume, Y.; Morita, I.; Kato, Y.; Yokoyama, K.; Ito, K. [Babcock Hitachi K.K., Kure-shi, Hiroshima-ken (Japan)

2004-07-01

Babcock Hitachi K.K. (BHK) received the contract of the rejuvenation of the SCR catalyst at the 750 MW coal-fired Mehrum Power Station (in Hohenhameln, Germany) in March 2003. The contractual coverage was 160 m{sup 3} of the entire catalyst layer. The catalyst, which had been in operation for 16 years since 1987, was originally supplied by BHK. The rejuvenation process developed for the Mehrum project consisted of two major steps: the first is to dust off the catalyst and remove the catalyst poison, and the second step is to add active material to enhance the catalyst activity. The catalyst must be dried after each washing. In order to minimize transportation cost and time, the rejuvenation work was done at the Mehrum station site. The scope of the rejuvenation work was shared between the owner and BHK. It took about one and a half months to complete the (total) on-site rejuvenation worked. The performance of the rejuvenated catalyst was superior to show the same level of activity as the unused catalyst and maintain the same SO{sub 2} conversion rate as the spent catalyst. This paper gives the details of the spent coal-fired SCR catalyst rejuvenation work. 13 figs., 1 tab.

Economic evaluation, human immunodeficiency virus infection and screening: a review and critical appraisal of economic studies.

Science.gov (United States)

Dibosa-Osadolor, Onome; Roberts, Tracy

2010-07-01

The aim of this study was to review, systematically and critically, evidence used to derive estimates of cost-effectiveness of human immunodeficiency virus (HIV) screening. A systematic review was conducted. Searched were three main electronic bibliographic databases from 1993 to 2008 using key words including HIV, mass screening, HAART, economic evaluation, cost-effectiveness analysis, modeling. We included studies of sexually transmitted HIV infection in both sexes, including studies comparing diagnostic testing protocols and partner notification. Outcomes included were cases of HIV infection detected, deterioration to the AIDS state, secondary transmission of HIV, the quality-adjusted life-years/survival, costs, and cost-effectiveness of HIV screening. Eighty-four papers were identified; ten of which were formal economic evaluations, one cost study, three effectiveness studies, and three systematic reviews of HIV prevention programs. The predominant assertion was that HIV screening is cost-effective; methodological problems, such as the preponderance of static models which are inappropriate for infectious diseases, varying perspectives from which the studies were analyzed, and arbitrary threshold incremental cost-effectiveness ratio levels, limited the validity of these findings, and their usefulness in informing health policy decisions. The majority of published economic evaluations are based on inappropriate static models. This flaw renders the results of these studies as inconclusive and the purported cost-effectiveness of HIV screening debatable. The results of this review could form a basis for consideration of further research and analysis by health economists into the cost-effectiveness of HIV screening.

SO2 influence on the K/La2O3 soot combustion catalyst deactivation

International Nuclear Information System (INIS)

Peralta, M.A.; Ulla, M.A.; Querini, C.A.

2008-01-01

In the present work, K/La 2 O 3 was prepared and tested as a potential catalyst to be used in a diesel engine exhaust. The soot combustion activity was evaluated by temperature-programmed-oxidation (TPO), and the NO x -catalyst interaction was studied using a microbalance experiment. The SO 2 poisoning process and the regeneration of a poisoned K/La 2 O 3 catalyst were analyzed. The fresh catalyst presented a good soot combustion activity. After being treated with a 1000 ppm SO 2 stream, the catalyst was poisoned due to lanthanum sulfate and potassium sulfate formation. The NO x treatment contributed to the K 2 (SO 4 ) decomposition at the expense of extra La 2 (SO 4 ) 3 formation and the H 2 treatment contributed to the La 2 (SO 4 ) 3 decomposition. (author)

FY 2000 report on the research cooperation project - Research cooperation in developmental support for oil producing countries. Production of catalyst and development of the evaluation technology in Kuwait; 2000 nendo san'yukoku kaihatsu shien kenkyu kyoryoku jigyo seika hokokusho. Kuuweto ni okeru shokubai seizo oyobi hyoka gijutsu no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-09-01

For the purpose of strengthening the economic infrastructure of Kuwait and also strengthening the relation between Japan and Kuwait by bringing up the catalyst production industry in Kuwait as one of the key industries, the research cooperation was made with Kuwait Catalyst Co. (KCC). In this research cooperation project, the following were conducted: survey of the catalyst production environment in Kuwait, survey of the actual condition of oil factories in Kuwait and the Middle East, trial production of the catalyst to meet the needs of Kuwait, evaluation of the catalyst suitable for oil factories in Kuwait and the Middle East and evaluation of the application conditions, development of technology for production/evaluation/application of the catalyst to meet the needs of Kuwait, etc. As to the trial catalyst production at KCC, the trial products for heavy oil desulfurization and light oil desulfurization stood comparison with the catalysts produced in Japan. KCC started trial operation in fall 2000, and the commercial production is smoothly continuing. In September 2001, the catalyst for heavy oil desulfurizer of KNPC, user, was delivered. The delivery to other users was also planned to be made. (NEDO)

European workshop on spent catalysts. Book of abstracts

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

In 1999 and 2002 two well attended workshops on recycling, regeneration, reuse and disposal of spent catalysts took place in Frankfurt. This series has been continued in Berlin. The workshop was organized in collaboration with DGMK, the German Society for Petroleum and Coal Science and Technology. Contributions were in the following areas of catalyst deactivation: recycling of spent catalysts in chemical and petrochemical industry, recycling of precious metal catalysts and heterogenous base metal catalysts, legal aspects of transboundary movements, catalyst regeneration, quality control, slurry catalysts, commercial reactivation of hydrotreating catalysts. (uke)

Screening history in women with cervical cancer in a Danish population-based screening program

DEFF Research Database (Denmark)

Kirschner, Benny; Poll, Susanne; Rygaard, Carsten

2011-01-01

The aim of this study was to explore the screening histories of all cervical cancers in a Danish screening population. The intention was to decide suboptimal sides of the screening program and to evaluate the significance of routine screening in the development of cervical cancer.......The aim of this study was to explore the screening histories of all cervical cancers in a Danish screening population. The intention was to decide suboptimal sides of the screening program and to evaluate the significance of routine screening in the development of cervical cancer....

Hydrocracking of α-Cellulose Using Co, Ni, and Pd Supported on Mordenite Catalysts

Directory of Open Access Journals (Sweden)

Wega Trisunaryanti

2018-02-01

Full Text Available Hydrocracking of α-cellulose has been conducted in a semi-batch reactor at 400, 450, and 500 °C with hydrogen flow (30 mL/min. for 4 h. Mordenite (MOR and Co, Ni and Pd metal supported on the MOR were used as solid catalysts. The catalysts were characterized using X-ray Diffractometer (XRD, Fourier Transform Infrared (FTIR spectroscopy, and Scanning Electron Microscopy (SEM to evaluate the physical-chemical properties. Energy Dispersive X-ray (EDX and Inductively Coupled Plasma (ICP were used to analyze the amount of metal impregnated on the catalysts. The liquid product was analyzed using Gas Chromatograph-Mass Spectroscopy (GC-MS. Thermal hydrocracking was also conducted at 450 °C with the amount of liquid product was 37.86 wt.%. The highest liquid conversion obtained by mordenite catalyst was 94.66 wt.% at 450 °C and the highest liquid conversion (98.08 wt.% was reached by Pd/MOR catalyst at 400 °C.

Cobalt oxide-based catalysts deposited by cold plasma for proton exchange membrane fuel cells

Energy Technology Data Exchange (ETDEWEB)

Kazimierski, P.; Jozwiak, L.; Sielski, J.; Tyczkowski, J., E-mail: jacek.tyczkowski@p.lodz.pl

2015-11-02

In proton exchange membrane fuel cells (PEMFC), both the anodic hydrogen oxidation reaction and the cathodic oxygen reduction reaction (ORR) require appropriate catalysts. So far, platinum-based catalysts are still the best option for this purpose. However, because these catalysts are too expensive for making commercially viable fuel cells, extensive research over the past decade has focused on developing noble metal-free alternative catalysts. In this paper, an approach based on cobalt oxide films fabricated by plasma-enhanced metal-organic chemical vapor deposition is presented. Such a material can be used to prepare catalysts for ORR in PEMFC. The films containing CoO{sub X} were deposited on a carbon paper thereby forming the electrode. Morphology and atomic composition of the films were investigated by scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. The possibility of their application as the electro-catalyst for ORR in PEMFC was investigated and the electro-catalytic activities were evaluated by the electrochemical measurements and single cell tests. It was found that the fuel cell with Pt as the anode catalyst and CoO{sub X} deposit as the cathode catalyst was characterized by the open circuit voltage of 635 mV, Tafel slope of approx. 130 mV/dec and the maximum power density of 5.3 W/m{sup 2}. - Highlights: • Cobalt oxide catalyst for proton exchange membrane fuel cells was plasma deposited. • The catalyst exhibits activity for the oxygen reduction reaction. • Morphology and atomic composition of the catalyst were determined.

Epoxidation catalyst and process

Science.gov (United States)

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.

Enhanced activity of Pt/CNTs anode catalyst for direct methanol fuel cells using Ni2P as co-catalyst

Science.gov (United States)

Li, Xiang; Luo, Lanping; Peng, Feng; Wang, Hongjuan; Yu, Hao

2018-03-01

The direct methanol fuel cell is a promising energy conversion device because of the utilization of the state-of-the-art platinum (Pt) anode catalyst. In this work, novel Pt/Ni2P/CNTs catalysts were prepared by the H2 reduction method. It was found that the activity and stability of Pt for methanol oxidation reaction (MOR) could be significantly enhanced while using nickel phosphide (Ni2P) nanoparticles as co-catalyst. X-ray photoelectron spectroscopy revealed that the existence of Ni2P affected the particle size and electronic distribution of Pt obviously. Pt/CNTs catalyst, Pt/Ni2P/CNTs catalysts with different Ni2P amount were synthesized, among which Pt/6%Ni2P/CNTs catalyst exhibited the best MOR activity of 1400 mAmg-1Pt, which was almost 2.5 times of the commercial Pt/C-JM catalyst. Moreover, compared to other Pt-based catalysts, this novel Pt/Ni2P/CNTs catalyst also exhibited higher onset current density and better steady current density. The result of this work may provide positive guidance to the research on high efficiency and stability of Pt-based catalyst for direct methanol fuel cells.

Supported nano gold as a recyclable catalyst for green, selective and efficient oxidation of alcohol using molecular oxygen

Directory of Open Access Journals (Sweden)

Bashir Dar

2011-09-01

Full Text Available The myth that gold cannot act as a catalyst has been discarded in view of recent studies, which have demonstrated the high catalytic efficiency of pure nano-gold and supported nano-gold catalysts. In recent years, numerous papers have described the use of supported nano-gold particles for catalysis in view of their action on CO and O2 to form CO2, as well as a variety of other reactions. Special emphasis is placed on the oxidation studies undertaken on model nano-Au systems. In this work a solvent free oxidation of 1-phenyl ethanol was carried out using gold supported on ceria-silica, ceria-titania, ceria- zirconia and ceria-alumina at 160 0C. Almost 88-97% conversion was obtained with >99% selectivity. Temperature screening was done from 70 to 160 0C.Catalysts were prepared by deposition co-precipitation method and deposition was determined by EDEX analysis.

Study of (La, Ce)(Pd, Mn, Fe, Co) O3-Perovskite catalysts characterization with nanoparticles produced by compressor and vacuum until 20/000 km and comparison with imported catalyst of Iran Khodro

International Nuclear Information System (INIS)

Khanfekr, A.; Arzani, K.; Nemati, A.; Hossaini, M.

2009-01-01

(La,Ce)(Pd,Mn,Fe,Co)O 3 - Perovskite catalyst was prepared by the citrate route and deposited on ceramic monoliths via dip coating procedure by compressor and vacuum method. The catalyst was applied on Rd car with XU7 motors model and the amount of emission was monitored with vehicle emission test systems in Sapco Company after 10000 and 20/000 Km. The results indicate low emission in catalyst with vacuum method and were compared with the imported catalyst with noble metals such as Palladium, Platinum and Rhodium by Iran Khodro Company b ased on the Euro III standards . The catalysts were characterized by specific surface area measurements, scanning electron microscopy, X-ray diffraction, line scan and map. In the results indicated in the home made sample, the amount of carbon monoxide, nitrogen oxides and hydrocarbons were lower than imported catalyst with Iran Khodro company with nobel metals. The illustration shows Nano Particles size on coat. The microstructure evaluation showed that the improved properties can he related to the existence of nano particles on coating.

Preparation and characterization of Pd doped ceria–ZnO nanocomposite catalyst for methyl tert-butyl ether (MTBE) photodegradation

International Nuclear Information System (INIS)

Seddigi, Zaki S.; Bumajdad, Ali; Ansari, Shahid P.; Ahmed, Saleh A.; Danish, Ekram Y.; Yarkandi, Naeema H.; Ahmed, Shakeel

2014-01-01

Highlights: • Novel Pd supported ceria–ZnO photocatalysts were prepared with different amounts of palladium. • The photocatalytic activity of these catalysts was evaluated for degradation of MTBE in water. • Near complete removal of MTBE was achieved using 1% Pd doped ceria–ZnO catalyst and UV irradiation. • Highest rate constant was obtained in case of 1% Pd doped ceria–ZnO catalyst. • Shape and size of pores are important factors for high photoactivity of catalyst. -- Abstract: A series of binary oxide catalysts (ceria–ZnO) were prepared and doped with different amounts of palladium in the range of 0.5%–1.5%. The prepared catalysts were characterized by SEM, TEM, XRD and XPS, as well as by N 2 sorptiometry study. The XPS results confirmed the structure of the Pd CeO 2−x -ZnO. The photocatalytic activity of these catalysts was evaluated for degradation of MTBE in water. These photocatalyst efficiently degrade a 100 ppm aqueous solution of MTBE upon UV irradiation for 5 h in the presence of 100 mg of each of these photocatalysts. The removal of 99.6% of the MTBE was achieved with the ceria–ZnO catalyst doped with 1% Pd. In addition to the Pd loading, the N 2 sorptiometry study introduced other factors that might affect the catalytic efficiency is the catalyst average pore sizes. The photoreaction was determined to be a first order reaction

Preparation and characterization of Pd doped ceria–ZnO nanocomposite catalyst for methyl tert-butyl ether (MTBE) photodegradation

Energy Technology Data Exchange (ETDEWEB)

Seddigi, Zaki S. [Chemistry Department, Umm Al-Qura University, Makkah (Saudi Arabia); Bumajdad, Ali [Chemistry Department, Faculty of Science, Kuwait University (Kuwait); Ansari, Shahid P. [Chemistry Department, Umm Al-Qura University, Makkah (Saudi Arabia); Ahmed, Saleh A., E-mail: saleh_63@hotmail.com [Chemistry Department, Umm Al-Qura University, Makkah (Saudi Arabia); Danish, Ekram Y. [Chemistry Department, King Abdulaziz University, Jeddah (Saudi Arabia); Yarkandi, Naeema H. [Chemistry Department, Umm Al-Qura University, Makkah (Saudi Arabia); Ahmed, Shakeel [Center for Refining and Petrochemicals, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2014-01-15

Highlights: • Novel Pd supported ceria–ZnO photocatalysts were prepared with different amounts of palladium. • The photocatalytic activity of these catalysts was evaluated for degradation of MTBE in water. • Near complete removal of MTBE was achieved using 1% Pd doped ceria–ZnO catalyst and UV irradiation. • Highest rate constant was obtained in case of 1% Pd doped ceria–ZnO catalyst. • Shape and size of pores are important factors for high photoactivity of catalyst. -- Abstract: A series of binary oxide catalysts (ceria–ZnO) were prepared and doped with different amounts of palladium in the range of 0.5%–1.5%. The prepared catalysts were characterized by SEM, TEM, XRD and XPS, as well as by N{sub 2} sorptiometry study. The XPS results confirmed the structure of the Pd CeO{sub 2−x}-ZnO. The photocatalytic activity of these catalysts was evaluated for degradation of MTBE in water. These photocatalyst efficiently degrade a 100 ppm aqueous solution of MTBE upon UV irradiation for 5 h in the presence of 100 mg of each of these photocatalysts. The removal of 99.6% of the MTBE was achieved with the ceria–ZnO catalyst doped with 1% Pd. In addition to the Pd loading, the N{sub 2} sorptiometry study introduced other factors that might affect the catalytic efficiency is the catalyst average pore sizes. The photoreaction was determined to be a first order reaction.

Rare earth metals for automotive exhaust catalysts

International Nuclear Information System (INIS)

Shinjoh, Hirohumi

2006-01-01

The usage of rare earth metals for automotive exhaust catalysts is demonstrated in this paper. Rare earth metals have been widely used in automotive catalysts. In particular, three-way catalysts require the use of ceria compounds as oxygen storage materials, and lanthana as both a stabilizer of alumina and a promoter. The application for diesel catalysts is also illustrated. Effects of inclusion of rare earth metals in automotive catalysts are discussed

Catalytic Oxidation of Cyanogen Chloride over a Monolithic Oxidation Catalyst

National Research Council Canada - National Science Library

Campbell, Jeffrey

1997-01-01

The catalytic oxidation of cyanogen chloride was evaluated over a monolithic oxidation catalyst at temperatures between 200 and 300 deg C in air employing feed concentrations between 100 and 10,000 ppm...

Alkaline Ionic Liquid Modified Pd/C Catalyst as an Efficient Catalyst for Oxidation of 5-Hydroxymethylfurfural

Directory of Open Access Journals (Sweden)

Zou Bin

2018-01-01

Full Text Available Conversion of HMF into FDCA was carried out by a simple and green process based on alkaline ionic liquid (IL modified Pd/C catalyst (Pd/C-OH−. Alkaline ionic liquids were chosen to optimize Pd/C catalyst for special hydrophilicity and hydrophobicity, redox stability, and unique dissolving abilities for polar compounds. The Pd/C-OH− catalyst was successfully prepared and characterized by SEM, XRD, TG, FT-IR, and CO2-TPD technologies. Loading of alkaline ionic liquid on the surface of Pd/C was 2.54 mmol·g−1. The catalyst showed excellent catalytic activity in the HMF oxidation after optimization of reaction temperature, reaction time, catalyst amount, and solvent. Supported alkaline ionic liquid (IL could be a substitute and promotion for homogeneous base (NaOH. Under optimal reaction conditions, high HMF conversion of 100% and FDCA yield of 82.39% were achieved over Pd/C-OH− catalyst in water at 373 K for 24 h.

Synthesis of Pt/rGO catalysts with two different reducing agents and their methanol electrooxidation activity

Energy Technology Data Exchange (ETDEWEB)

Vu, Thu Ha Thi, E-mail: ptntd2004@yahoo.fr [Key Laboratory for Petrochemical and Refinery Technologies, 2 Pham Ngu Lao street, Hanoi (Viet Nam); Tran, Thanh Thuy Thi, E-mail: tranthithanhthuygl@gmail.com [Key Laboratory for Petrochemical and Refinery Technologies, 2 Pham Ngu Lao street, Hanoi (Viet Nam); Le, Hong Ngan Thi; Tran, Lien Thi; Nguyen, Phuong Hoa Thi; Nguyen, Minh Dang [Key Laboratory for Petrochemical and Refinery Technologies, 2 Pham Ngu Lao street, Hanoi (Viet Nam); Quynh, Bui Ngoc [Institut de recherches sur la catalyse et l’environnement de Lyon, UMR5256, 2 avenue Albert Einstein, 69626 Villeurbanne cedex (France)

2016-01-15

Highlights: • Pt/rGO catalysts were successfully synthesized using either NaBH{sub 4} or ethylene glycol. • Synthesis using NaBH{sub 4} could improve electrocatalytic towards methanol oxidation of Pt/rGO catalyst. • 40%Pt/rGO synthesized using NaBH{sub 4} showed the best electrocatalytic performance. - Abstract: The synthesis processes of Platinum (Pt) on reduced graphene oxide (rGO) catalysts from graphene oxide (GO) using two reducing agents including sodium borohydride and ethylene glycol is reported. Structure and morphology of Pt/rGO catalysts are characterized by X-ray powder diffraction, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrocatalytic methanol oxidation properties of these catalysts are evaluated by cyclic voltammetry and chronoamperometry. The results show that catalyst synthesized using sodium borohydride has a higher metallic Pt content and an improved catalytic performance in comparison to catalyst synthesized using ethylene glycol. Moreover, effect of Pt loading amount on electrocatalytic methanol oxidation performance of catalysts synthesized using sodium borohydride is systematically investigated. The optimal Pt loading amount on graphene is determined to be 40%.

Shape-selective catalysts for Fischer-Tropsch chemistry. Final report : January 1, 2001 - December 31, 2008.

Energy Technology Data Exchange (ETDEWEB)

Cronauer, D. C. (Chemical Sciences and Engineering Division)

2011-04-11

Argonne National Laboratory carried 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 was desirable that the catalysts have high selectivity and stability with respect to both mechanical strength and aging properties. It was desired that selectivity be directed toward producing diesel fraction components and avoiding excess yields of both light hydrocarbons and heavy waxes. The original goal was to produce shape-selective catalysts that had the potential to limit the formation of long-chain products and yet retain the active metal sites in a protected 'cage.' This cage would also restrict 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. Such catalysts were prepared with silica-containing fractal cages. The activity and strength was essentially the same as that of catalysts without the cages. Since there was no improvement, the program plan was modified as discussed below. A second experimental stage was undertaken to prepare and evaluate active FT catalysts formed by atomic-layer deposition [ALD] of active components on supported membranes and particulate supports. The concept was that of depositing active metals (i.e. ruthenium, iron or cobalt) upon membranes with well defined flow channels of small diameter and length such that the catalytic activity and product molecular weight distribution could be controlled. In order to rapidly evaluate the catalytic membranes, the ALD coating processes were performed in an 'exploratory mode' in which ALD procedures from the literature appropriate for coating flat surfaces were applied to the high surface area membranes. Consequently, the Fe and Ru loadings in the membranes were likely to be smaller than those

Carbonaceous deposits on naptha reforming catalysts

International Nuclear Information System (INIS)

Redwan, D.S.

1999-01-01

Carbonaceous deposits on naphtha reforming catalysts play a decisive role in limiting process performance. The deposits negatively after catalyst activity, selectivity and the production cycle of a semi regenerative reformer. The magnitude of negative effect of those deposits is directly proportional to their amounts and complexity. Investigations on used reforming catalysts samples reveal that the amount and type (complexity of the chemical nature) of carbonaceous deposits are directly proportional to the catalysts life on stream and the severity of operating conditions. In addition, the combustibility behavior of carbonaceous deposits on the catalyst samples taken from different reformers are found to be different. Optimal carbon removal, for in situ catalyst regeneration, requires the specific conditions be developed, based on the results of well designed and properly performed investigations of the amount and type of carbonaceous deposits. (author)

Reducible oxide based catalysts

Science.gov (United States)

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.

Synthesis of a highly active carbon-supported Ir-V/C catalyst for the hydrogen oxidation reaction in PEMFC

International Nuclear Information System (INIS)

Li Bing; Qiao Jinli; Yang Daijun; Zheng Junsheng; Ma Jianxin; Zhang Jiujun; Wang Haijiang

2009-01-01

The active, carbon-supported Ir and Ir-V nanoclusters with well-controlled particle size, dispersity, and composition uniformity, have been synthesized via an ethylene glycol method using IrCl 3 and NH 4 VO 3 as the Ir and V precursors. The nanostructured catalysts were characterized by X-ray diffraction and high-resolution transmission electron microscopy. The catalytic activities of these carbon-supported nanoclusters were screened by applying on-line cyclic voltammetry and electrochemical impedance spectroscopy techniques, which were used to characterize the electrochemical properties of fuel cells using several anode Ir/C and Ir-V/C catalysts. It was found that Ir/C and Ir-V/C catalysts affect the performance of electrocatalysts significantly based on the discharge characteristics of the fuel cell. The catalyst Ir-V/C at 40 wt.% displayed the highest catalytic activity to hydrogen oxidation reaction and, therefore, high cell performance is achieved which results in a maximum power density of 563 mW cm -2 at 0.512 V and 70 deg. C in a real H 2 /air fuel cell. This performance is 20% higher as compared to the commercial available Pt/C catalyst. Fuel cell life test at a constant current density of 1000 mA cm -2 in a H 2 /O 2 condition shows good stability of anode Ir-V/C after 100 h of continuous operation.

Evaluation of a screening instrument for autism spectrum disorders in prisoners.

Directory of Open Access Journals (Sweden)

Louise Robinson

Full Text Available UNLABELLED: There have been concerns that individuals with autism spectrum disorders (ASDs are over-represented but not recognised in prison populations. A screening tool for ASDs in prisons has therefore been developed. AIMS: We aimed to evaluate this tool in Scottish prisoners by comparing scores with standard measures of autistic traits (Autism Quotient (AQ, neurodevelopmental history (Asperger Syndrome (and High-Functioning Autism Diagnostic Interview (ASDI, and social cognition (Ekman 60 Faces test. METHODS: Prison officers across all 12 publicly-run closed prisons in Scotland assessed convicted prisoners using the screening tool. This sample included male and female prisoners and both adult and young offenders. Prisoners with high scores, along with an equal number of age and sex-matched controls, were invited to take part in interviews. Prisoners' relatives were contacted to complete a neurodevelopmental assessment. RESULTS: 2458 prisoners were screened using the tool, and 4% scored above the cut-off. 126 prisoners were further assessed using standardised measures. 7 of those 126 assessed scored 32 or above (cut-off on the AQ. 44 interviews were completed with prisoners' relatives, no prisoner reached the cut-off score on the ASDI. Scores on the screening tool correlated significantly with AQ and ASDI scores, and not with the Ekman 60 Faces Test or IQ. Sensitivity was 28.6% and specificity 75.6%; AUC was 59.6%. CONCLUSIONS: Although this screening tool measures autistic traits in this population, sensitivity for scores of 32 or above on the AQ is poor. We consider that this limits its usefulness and do not recommend that the tool is routinely used to screen for ASDs in prisons.

Study of the performance of vanadium based catalysts prepared by grafting in the oxidative dehydrogenation of propane

Energy Technology Data Exchange (ETDEWEB)

Santacesaria, E.; Carotenuto, G.; Tesser, R.; Di Serio, M. [Naples Univ. (Italy). Dept. of Chemistry

2011-07-01

The oxidative dehydrogenation (ODH) of propane has been investigated by using many different vanadia based catalysts, prepared by grafting technique and containing variable amounts of active phase supported on SiO{sub 2} previously coated, by grafting in three different steps, with multilayer of TiO{sub 2}. A depth catalytic screening, conducted in a temperature range of 400-600 C, at atmospheric pressure and in a range of residence time W/F=0.08-0.33 ghmol{sub -1}, has shown that the vanadium oxide catalysts on TiO{sub 2}-SiO{sub 2} support, prepared by grafting have good performances in the ODH of propane. In particular, a preliminary study has demonstrated that higher selectivities can be obtained employing catalysts having a well dispersed active phase that can be achieved with a V{sub 2}O{sub 5} content lower than 10%{sub w}t. It is well known that, in the case of redox catalysts, an increase of the selectivity can be achieved not only by using an adequate catalytic system but also via engineering routes like decoupling catalytic steps of reduction and re-oxidation. In fact it has been observed that by operating in dehydrogenating mode, on the same catalysts, a higher selectivity is obtained although the catalyst is poisoned by the formation of coke on the surface. As consequence of the results obtained in dehydrogenation, in this work has been explored the possibility to feed low amounts of oxygen, below the stoichiometric level with the aim to keep clean the surface from coke but maintaining high the selectivity, because, dehydrogenation reaction prevails. In this work, the behavior of catalysts containing different amounts of V2O5 has been studied in the propane-propene reaction by using different ratios C{sub 3}H{sub 8}/O{sub 2} included in the range 0-2. (orig.)

Increasing the lifetime of fuel cell catalysts

NARCIS (Netherlands)

Latsuzbaia, R.

2015-01-01

In this thesis, I discuss a novel idea of fuel cell catalyst regeneration to increase lifetime of the PEM fuel cell electrode/catalyst operation and, therefore, reduce the catalyst costs. As many of the catalyst degradation mechanisms are difficult to avoid, the regeneration is alternative option to

A systematic review of hepatitis B screening economic evaluations in low- and middle-income countries.

Science.gov (United States)

Wright, Cameron M; Boudarène, Lydia; Ha, Ninh Thi; Wu, Olivia; Hawkins, Neil

2018-03-20

Chronic hepatitis B infection is a significant cause of morbidity and mortality worldwide; low- and middle-income countries (LMICs) are disproportionately affected. Economic evaluations are a useful decision tool to assess costs versus benefits of hepatitis B virus (HBV) screening. No published study reviewing economic evaluations of HBV screening in LMICs has been undertaken to date. The following databases were searched from inception to 21 April 2017: MEDLINE, PubMed, EMBASE, CINAHL Plus, the Cochrane Library, Global Health and the Cost-effectiveness Analysis Registry. English-language studies were included if they assessed the costs against the benefits of HBV screening in LMICs. PROSPERO registration: CRD42015024391, 20 July 2015. Nine studies fulfilled the eligibility criteria. One study from Thailand indicated that adding hepatitis B immunoglobulin (HBIG) to HBV vaccination for newborns following screening of pregnant women might be cost-effective for some LMICs, though inadequate total funding and health infrastructure were likely to limit feasibility. A similar study from China indicated a benefit to cost ratio of 2.7 from selective HBIG administration to newborns, if benefits were considered from a societal perspective. Of the two studies assessing screening amongst the general adult population, a single cost-benefit analysis from China found a benefit to cost ratio (BCR) of 1.73 with vaccination guided by HBV screening of adults aged 21-39, compared to 1.42 with vaccination with no screening, both from a societal perspective. Community-based screening of adults in The Gambia with linkage to treatment yielded an incremental cost per disability-adjusted life year averted of $566 (in 2017 USD), less than two-times gross domestic product per capita for that country. Screening with 'catch-up' vaccination for younger adults yielded benefits above costs, and screening linked with treatment has shown cost-effectiveness that may be affordable for some LMICs

Catalytic fast pyrolysis of durian rind using silica-alumina catalyst: Effects of pyrolysis parameters.

Science.gov (United States)

Tan, Y L; Abdullah, A Z; Hameed, B H

2018-05-18

Silica-alumina catalyst was prepared and used in the catalytic fast pyrolysis of durian rind in a drop-type two-stage reactor. The effects of catalytic temperature (400 °C-600 °C) and catalyst-to-durian rind ratio (1:30-3:30) were evaluated. Bio-oil yield was increased with increased catalytic temperature due to considerable dehydration process, but it was reduced with high catalyst loading due to the overcracking of organics into light gases. Silica-alumina catalyst possessed good selectivity and the products changed according to the temperature. The major components in bio-oil were hydrocarbons, furan derivatives, and aromatic compounds at 400 °C, 500 °C, and 600 °C, respectively. The hydrogen and carbon contents of bio-oil were reduced with high catalyst loading due to the overcracking of organics, and the deoxygenation process became unfavorable. The silica-alumina catalyst worked well in catalytic fast pyrolysis of durian rind, and the condition may be adjusted based on the desired products. Copyright © 2018 Elsevier Ltd. All rights reserved.

The effect of diluting ruthenium by iron in Ru{sub x}Se{sub y} catalyst for oxygen reduction

Energy Technology Data Exchange (ETDEWEB)

Delacote, Cyril [Laboratory of Electrocatalysis, CNRS, University of Poitiers, F-86022 Poitiers Cedex (France); CEISAM, CNRS, University of Nantes, F-44322 Nantes Cedex 3 (France); Lewera, Adam [University of Warsaw, Department of Chemistry, ul. Pasteura 1, 02-093 Warsaw (Poland); Pisarek, Marcin [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland); Kulesza, Pawel J. [University of Warsaw, Department of Chemistry, ul. Pasteura 1, 02-093 Warsaw (Poland); Zelenay, Piotr [Materials Physics and Applications, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Alonso-Vante, Nicolas, E-mail: nicolas.alonso.vante@univ-poitiers.f [Laboratory of Electrocatalysis, CNRS, University of Poitiers, F-86022 Poitiers Cedex (France)

2010-11-01

This study has focused on the synthesis of novel oxygen reduction reaction (ORR) chalcogenide catalysts, with Ru partially replaced by Fe in a cluster-type Ru{sub x}Se{sub y}. The catalysts were obtained by thermal decomposition of Ru{sub 3}(CO){sub 12} and Fe(CO){sub 5} in the presence of Se. As indicated by the XPS data, the composition of catalyst nanoparticles depends on the solvent used (either p-xylene or dichlorobenzene). The presence of iron in synthesized catalysts has been confirmed by both EDAX and XPS. Voltammetric activation of the catalysts results in a partial removal of iron and unreacted selenium from the surface. The ORR performance of electrochemically pre-treated catalysts was evaluated using rotating disk and ring-disk electrodes in a sulfuric acid solution. No major change in the ORR mechanism relative to the Se/Ru catalyst has been observed with Fe-containing catalysts.

Hydroprocessing using regenerated spent heavy hydrocarbon catalyst

International Nuclear Information System (INIS)

Clark, F.T.; Hensley, A.L. Jr.

1992-01-01

This patent describes a process for hydroprocessing a hydrocarbon feedstock. It comprises: contacting the feedstock with hydrogen under hydroprocessing conditions with a hydroprocessing catalyst wherein the hydroprocessing catalyst contains a total contaminant metals build-up of greater than about 4 wt. % nickel plus vanadium, a hydrogenation component selected from the group consisting of Group VIB metals and Group VIII metals and is regenerated spent hydroprocessing catalyst regenerated by a process comprising the steps: partially decoking the spent catalyst in an initial coke-burning step; impregnating the partially decoked catalyst with a Group IIA metal-containing impregnation solution; and decoking the impregnated catalyst in a final coke-burning step wherein the impregnated catalyst is contacted with an oxygen-containing gas at a temperature of about 600 degrees F to about 1400 degrees F

Evaluating the NOx Storage Catalysts (NSC Aging: A Preliminary Analytical Study with Electronic Microscopy

Directory of Open Access Journals (Sweden)

Leonarda Bellebuono

2017-10-01

Full Text Available This paper describes an expeditious and reliable method for determining the thermal effects in a static condition of commercial NOx storage catalysts (NSCs using scanning electron microscopy with an energy dispersive X-ray analytical system (SEM/EDS. It is worth remarking that possible changes in the morphology and in the elemental composition of the catalyst may be considered as the most important causes of the lower conversion of NOx. The information attained in this work indicates that Pt nanoparticle sintering is strongly increased by the oxygen exposure, and this can be considered a very useful preliminary investigation for the studies already present in the literature on the efficiency of NSCs.

Extended Catalyst Longevity Via Supercritical Isobutane Regeneration of a Partially Deactivated USY Alkylation Catalyst

Energy Technology Data Exchange (ETDEWEB)

Daniel M. Ginosar; David N. Thompson; Kyle C. Burch; David J. Zalewski

2005-05-01

Off-line, in situ activity recovery of a partially deactivated USY zeolite catalyst used for isobutane/butene alkylation was examined in a continuous-flow reaction system employing supercritical isobutane. Catalyst samples were deactivated in a controlled manner by running them to either to a fixed butene conversion level of 95% or a fixed time on stream of three hours, and then exposing the catalyst to supercritical isobutane to restore activity. Activity recovery was determined by comparing alkylation activity before and after the regeneration step. Both single and multiple regenerations were performed. Use of a 95% butene conversion level criterion to terminate the reaction step afforded 86% activity recovery for a single regeneration and provided nine sequential reaction steps for the multiple regeneration studies. Employing a fixed 3 h time on stream criterion resulted in nearly complete activity recovery for a single regeneration, and 24 reaction steps were demonstrated in sequence for the multiple regeneration process, producing only minor product yield declines per step. This resulted in a 12-fold increase in catalyst longevity versus unregenerated catalyst.

Calcium-based mixed oxide catalysts for methanolysis of Jatropha curcas oil to biodiesel

International Nuclear Information System (INIS)

Taufiq-Yap, Y.H.; Lee, H.V.; Hussein, M.Z.; Yunus, R.

2011-01-01

Calcium-based mixed oxides catalysts (CaMgO and CaZnO) have been investigated for the transesterification of Jatropha curcas oil (JCO) with methanol, in order to evaluate their potential as heterogeneous catalysts for biodiesel production. Both CaMgO and CaZnO catalysts were prepared by coprecipitation method of the corresponding mixed metal nitrate solution in the presence of a soluble carbonate salt at ∼ pH 8-9. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed desorption of CO 2 (CO 2 -TPD), scanning electron microscopy (SEM) and N 2 adsorption (BET). The conversion of JCO by CaMgO and CaZnO were studied and compared with calcium oxide (CaO), magnesium oxide (MgO) and zinc oxide (ZnO) catalysts. Both CaMgO and CaZnO catalysts showed high activity as CaO and were easily separated from the product. CaMgO was found more active than CaZnO in the transesterification of JCO with methanol. Under the suitable transesterification conditions at 338 K (catalyst amount = 4 wt. %, methanol/oil molar ratio = 15, reaction time = 6 h), the JCO conversion of more than 80% can be achieved over CaMgO and CaZnO catalysts. Even though CaO gave the highest activity, the conversion of JCO decreased significantly after reused for forth run whereas the conversion was only slightly lowered for CaMgO and CaZnO after sixth run.

The Stability of Supported Gold Catalysts

NARCIS (Netherlands)

Masoud, Nazila

2018-01-01

Gold has supreme cultural and financial value and, in form of nanoparticles smaller than 10 nm, is a unique catalyst for different industrially relevant reactions. Intriguing properties of the gold catalysts have spurred demand in the chemical industry for Au catalysts, the application of which

Evaluation of biodiesel fuel and oxidation catalyst in an underground metal mine : revised final report

Energy Technology Data Exchange (ETDEWEB)

Watts, W.F. Jr.; Spears, M.; Johnson, J. [Minnesota Univ., St. Paul, MN (United States); Birch, E.; Cantrell, B.K. [National Inst, for Occupational Safety and Health, Morgantown, VW (United States); Grenier, M. [Canada Centre for Mineral and Energy Technology, Ottawa, ON (Canada); Walker, J. [Ortech International, Mississauga, ON (Canada); Bagley, S. [Michigan Technological Univ., Houghton, MI (United States); Maskery, D.; Stachulak, J.S.; Conard, B.R. [Inco Ltd., Toronto, ON (Canada)

1998-09-24

The impact of blended biodiesel fuel and modern diesel oxidation catalyst (DOC) on air quality and diesel emissions were evaluated. The study was conducted in October 1997 at Inco's Creighton Mine in Sudbury, Ontario. The concentration of diesel particulate matter (DPM) and exhaust gas emissions in a non-producing test section were characterized. A diesel-powered scoop was operated on low sulfur, number 2 diesel fuel (D2) during the first week of the evaluation. The scoop was operated on 58 per cent (by mass) blend of soy methyl ester (SME) biodiesel fuel and a low sulfur D2 during the second week. A pair of identical, advanced design DOC equipped the scoop. The changes in exhaust emissions and an estimation of the operating costs of a test vehicle fueled with blended biodiesel were determined and represented the objectives of the study. A summary of the data collected for the determination in the difference in gaseous and particulate matter concentrations attributable to the use of a blended biodiesel fuel and catalyst was presented. The Emissions Assisted Maintenance Procedure (EAMP) was used to determine the day-to-day variation in emissions. The DOCs performed as expected and there were no major changes in engine emissions. An increase in nitrogen dioxide concentrations was noted, and carbon monoxide was effectively removed. The combination of the blended biodiesel fuel and DOCs used in this study decreased total carbon emissions by approximately 21 per cent, as indicated by air samples collected in the test section. During both weeks, sulphur dioxide levels were low. In an underground mine, the use of biodiesel fuel un combination with DOCs represents a passive control option. Cost is an obstacle, biodiesel selling for 3.00 to 3.50 American dollars per gallon. It is estimated that using a 50 per cent blended biodiesel fuel would cost between 2.00 and 2.25 American dollars per gallon. 35 refs., 18 tabs., 10 figs.

Nitrogen oxides storage catalysts containing cobalt

Science.gov (United States)

Lauterbach, Jochen; Snively, Christopher M.; Vijay, Rohit; Hendershot, Reed; Feist, Ben

2010-10-12

Nitrogen oxides (NO.sub.x) storage catalysts comprising cobalt and barium with a lean NO.sub.x storage ratio of 1.3 or greater. The NO.sub.x storage catalysts can be used to reduce NO.sub.x emissions from diesel or gas combustion engines by contacting the catalysts with the exhaust gas from the engines. The NO.sub.x storage catalysts can be one of the active components of a catalytic converter, which is used to treat exhaust gas from such engines.

FCC catalyst technologies expand limits of process capability

International Nuclear Information System (INIS)

Leiby, S.

1992-01-01

This paper reports that over the past 30 or so years, many improvements in fluid catalytic cracking (FCC) operation have been achieved as the result of innovations in catalyst formulation. During the 1990s, new environmental regulations on issues such as reformulated gasoline will place new demands on both the refining industry and catalyst suppliers. An overview of cracking catalyst technology therefore seems in order. Today, high-technology innovations by catalyst manufacturers are rapid, but profit margins are slim. Catalyst formulations are shrouded in secrecy and probably depend almost as much on art as on science. Special formulations for specific cracking applications get the greatest emphasis today. To illustrate this point, OGJ's Worldwide Catalyst Report lists over 200 FCC catalyst designations. Catalysts containing components to enhance gasoline octane now account for about 70% of total U.S. FCC catalyst usage

Catalyst design for enhanced sustainability through fundamental surface chemistry.

Science.gov (United States)

Personick, Michelle L; Montemore, Matthew M; Kaxiras, Efthimios; Madix, Robert J; Biener, Juergen; Friend, Cynthia M

2016-02-28

Decreasing energy consumption in the production of platform chemicals is necessary to improve the sustainability of the chemical industry, which is the largest consumer of delivered energy. The majority of industrial chemical transformations rely on catalysts, and therefore designing new materials that catalyse the production of important chemicals via more selective and energy-efficient processes is a promising pathway to reducing energy use by the chemical industry. Efficiently designing new catalysts benefits from an integrated approach involving fundamental experimental studies and theoretical modelling in addition to evaluation of materials under working catalytic conditions. In this review, we outline this approach in the context of a particular catalyst-nanoporous gold (npAu)-which is an unsupported, dilute AgAu alloy catalyst that is highly active for the selective oxidative transformation of alcohols. Fundamental surface science studies on Au single crystals and AgAu thin-film alloys in combination with theoretical modelling were used to identify the principles which define the reactivity of npAu and subsequently enabled prediction of new reactive pathways on this material. Specifically, weak van der Waals interactions are key to the selectivity of Au materials, including npAu. We also briefly describe other systems in which this integrated approach was applied. © 2016 The Author(s).

Catalyst Deactivation and Regeneration in Low Temperature Ethanol Steam Reforming with Rh/CeO2-ZrO2 Catalysts

Energy Technology Data Exchange (ETDEWEB)

Roh, Hyun-Seog; Platon, Alex; Wang, Yong; King, David L.

2006-08-01

Rh/CeO2-ZrO2 catalysts with various CeO2/ZrO2 ratios have been applied to H2 production from ethanol steam reforming at low temperatures. The catalysts all deactivated with time on stream (TOS) at 350 C. The addition of 0.5% K has a beneficial effect on catalyst stability, while 5% K has a negative effect on catalytic activity. The catalyst could be regenerated considerably even at ambient temperature and could recover its initial activity after regeneration above 200 C with 1% O2. The results are most consistent with catalyst deactivation due to carbonaceous deposition on the catalyst.

Montmorillonite Supported Titanium/Antimony Catalyst:Preparation, Characterization and Immobilization

Institute of Scientific and Technical Information of China (English)

CHEN Guiyong; WANG Xiaoqun; ZHAO Chuan; DU Shanyi

2014-01-01

Montmorillonite supported titanium (Ti-MMT) or antimony catalyst (Sb-MMT) has been a hot area of research on preparing polyethylene terephthalate/montmorillonite (PET/MMT) nanocomposites by in situ polymerization. So removal of Ti or Sb from Ti-MMT or Sb-MMT is not expected during in situ polymerization. Studies on immobilization of Ti or Sb on Ti-MMT or Sb-MMT are seldom reported. In this work, a series of montmorillonite supported catalysts of titanium (Ti-MMT) or antimony (Sb-MMT) and co-intercalated montmorillonite of titanium and antimony (Ti/Sb-MMT) were prepared by (1) the reaction of sodium bentonite suspension with intercalating solution containing titanium tetrachloride and/or antimony chloride, and (2) drying or calcinating the products at different temperature (100, 150, 240, 350 and 450℃). The physicochemical properties of these MMT supported catalysts were studied by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma optical emission spectrometer (ICPOES), N2 adsorption/desorption isotherms, UV-visible diffuse reflectance spectroscopy(UV-vis) and transmission electron microscopy (TEM). The immobile character of Ti or Sb on MMT supported catalysts was evaluated by a two-step method in deionized water or ethylene glycol. Several results were obtained, i e, (a) during the preparation, with an increase in drying or calcinating temperature, the amount of titanium and/or antimony species remained on these MMT supported catalysts decreased, (b) the experiments about immobile character of Ti or/and Sb showed that with an increase in drying or calcinating temperature, the immobilization of Ti and/or Sb species remained on these MMT supported catalysts increased gradually, (c) Ti-MMT calcinated at 450℃had the biggest pore volume, which means Ti-MMT had the best adsorption application prospect.

Catalyst for Ammonia Oxidation

DEFF Research Database (Denmark)

2015-01-01

The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

Comparação entre avaliação audiológica e screening: um estudo sobre presbiacusia Comparing audiological evaluation and screening: a study on presbycusis

Directory of Open Access Journals (Sweden)

Alessandra Giannella Samelli

2011-02-01

Full Text Available Em virtude da alta prevalência da presbiacusia e dos prejuízos por ela trazidos, uma triagem pode ser útil na identificação da perda auditiva em atenção primária. OBJETIVOS: Estimar a prevalência da perda auditiva em uma população de idosos residentes no Butantã utilizando o método de screening audiológico (questionário e a avaliação audiológica básica; comparar os resultados do screening audiológico e da avaliação audiológica básica, verificando a validade deste instrumento como forma de triagem auditiva. FORMA DE ESTUDO: Do tipo transversal, descritivo. MATERIAL E MÉTODO: Foram selecionados randomicamente 200 sujeitos de ambos os sexos, com faixa etária a partir de 60 anos, para aplicação do screening audiológico (questionário e, destes, 100 indivíduos realizaram a avaliação audiológica completa. Em seguida, os resultados dos dois métodos de avaliação foram comparados. RESULTADOS: Verificou-se que não existe associação estatisticamente significante entre a queixa, obtida pelo questionário e o grau de perda auditiva. CONCLUSÕES: A prevalência de perda auditiva encontrada para esta população foi de aproximadamente 56% pelo screening e de 95% pela avaliação audiológica básica. Desta forma, o screening não se mostrou como instrumento válido para uso em triagem auditiva, quando comparado à avaliação audiológica básica.Given the high prevalence of presbycusis and the damage it brings about, a screening test can be useful in the identification of hearing loss in primary care. AIM: To estimate the prevalence of hearing loss in a representative sample of elderly people living at Butantan using an audiological screening method (questionnaire and a basic audiological evaluation; to compare the results of the two kinds of evaluations, checking the validity of this tool for hearing loss screening. DESIGN: Cross sectional descriptive study. MATERIALS AND METHODS: 200 individuals (above 60 years old

Synthesis of thiazolium salts and their screening for catalytic activity

Energy Technology Data Exchange (ETDEWEB)

Lee, Seul Ki; Kim, Do Joong; Park, Jin Kyoon [Dept. of Chemistry and Institute of Functional Materials, Pusan National University, Busan (Korea, Republic of)

2015-05-15

A facile synthetic method to prepare thiazolium-based ionic liquids in high yield was developed. The direct alkylation of thiazole was performed using a trialkyl orthoester as both the alkyl donor and the solvent. The synthesized thiazolium salts were subsequently screened for their ability to catalyze the benzoin condensation reaction. Of the salts that were tested, 3-butyl,4,5-dimethyl thiazolium salt, was found to be the best catalyst.

Petroleum residue upgrading with dispersed catalysts. Part 1. Catalysts activity and selectivity

Energy Technology Data Exchange (ETDEWEB)

Panariti, N.; Del Bianco, A.; Del Piero, G. [ENITECNOLOGIE S.p.A, Via Maritano 26, 20097 San Donato Mil. (Italy); Marchionna, M. [SNAMPROGETTI S.p.A, Via Maritano 26, 20097 San Donato Mil. (Italy)

2000-12-04

The results of a study aimed at the identification of the relevant chemical aspects involved in the process of upgrading heavy feedstocks in the presence of dispersed catalysts are discussed. The catalytic activity of different compounds was compared in terms of products yields and quality. Moreover, a detailed and systematic characterization of the catalysts recovered at the end of the reactions was achieved. The experimental work provided quite a large set of data, allowing to investigate the factors that may affect catalyst activity (precursor solubility, rate of activation, degree of dispersion, presence of promoters, etc.). The results of this study demonstrate that the best performances are obtained by the microcrystalline molybdenite generated in situ by oil-soluble precursors. The nature of the organic ligand does not play a very relevant role in influencing the hydrogenation activity. The presence of phosphorus, however, significantly enhances hydrodemetallation, at least in terms of vanadium removal. Bimetallic precursors show a slight synergistic effect towards the hydrodesulfurization reaction. Microsized powdered catalyst precursors have a much lower catalytic activity compared to the oil-soluble ones.

Performance indicators evaluation of the population-based breast cancer screening programme in Northern Portugal using the European Guidelines.

Science.gov (United States)

Bento, Maria José; Gonçalves, Guilherme; Aguiar, Ana; Castro, Clara; Veloso, Vitor; Rodrigues, Vítor

2015-10-01

To evaluate the first 10 years of operation of the population-based breast cancer screening programme implemented in the Northern Region of Portugal, using selected recommended standard performance indicators. Data from women aged 50-69 screened with two-view mammography, biennially, in the period 2000-2009, were included. Main performance indicators were compared with the recommended levels of the European Guidelines. A total of 202,039 screening examinations were performed, 71,731 (35.5%) in the initial screening and 130,308 (64.5%) in the subsequent screening. Coverage rate by examination reached 74.3% of the target population, in the last period evaluated. Recall rates were 8.1% and 2.4% and cancer detection rates were 4.4/1000 and 2.9/1000 respectively, for initial and subsequent screenings. The breast cancer detection rate, expressed as a multiple of the background expected incidence was 3.1 in initial screen and 2.2 in subsequent screen. The incidence of invasive interval cancers met the desirable recommended levels both the first and second years since last screening examination, in the initial and subsequent screenings. Invasive tumours cancers detected in initial and subsequent screenings. Less favourable size, grading and biomarkers expression were found in interval cancers compared to screen-detected cancers. Breast cancer screening programme in the Northern Region of Portugal was well accepted by the population. Most of the performance indicators were consistent with the desirable levels of the European Guidelines, which indicate an effective screening programme. Future research should verify the consistency of some of these results by using updated information from a larger population. Copyright © 2015 Elsevier Ltd. All rights reserved.

DEVELOPMENT OF PRECIPITATED IRON FISCHER-TROPSCH CATALYSTS

International Nuclear Information System (INIS)

Bukur, Dragomir B.; Lang, X.; Chokkaram, S.; Nowicki, L.; Wei, G.; Ding, Y.; Reddy, B.; Xiao, S.

1999-01-01

Despite the current worldwide oil glut, the US will ultimately require large-scale production of liquid (transportation) fuels from coal. Slurry phase Fischer-Tropsch (F-T) technology, with its versatile product slate, may be expected to play a major role in production of transportation fuels via indirect coal liquefaction. Some of the F-T catalysts synthesized and tested at Texas A and M University under DOE Contract No. DE-AC22-89PC89868 were more active than any other known catalysts developed for maximizing production of high molecular weight hydrocarbons (waxes). The objectives of the present contract were to demonstrate repeatability of catalyst performance and reproducibility of preparation procedures of two of these catalysts on a laboratory scale. Improvements in the catalyst performance were attempted through the use of: (a) higher reaction pressure and gas space velocity to maximize the reactor productivity; (b) modifications in catalyst preparation steps; and (c) different pretreatment procedures. Repeatability of catalyst performance and reproducibility of catalyst synthesis procedure have been successfully demonstrated in stirred tank slurry reactor tests. Reactor space-time-yield was increased up to 48% by increasing reaction pressure from 1.48 MPa to 2.17 MPa, while maintaining the gas contact time and synthesis gas conversion at a constant value. Use of calcination temperatures above 300 C, additional CaO promoter, and/or potassium silicate as the source of potassium promoter, instead of potassium bicarbonate, did not result in improved catalyst performance. By using different catalyst activation procedures they were able to increase substantially the catalyst activity, while maintaining low methane and gaseous hydrocarbon selectivities. Catalyst productivity in runs SA-0946 and SA-2186 was 0.71 and 0.86 gHC/g-Fe/h, respectively, and this represents 45-75% improvement in productivity relative to that achieved in Rheinpreussen's demonstration plant

Catalyst systems and uses thereof

Science.gov (United States)

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.

Samarium-modified vanadium phosphate catalyst for the selective oxidation of n-butane to maleic anhydride

International Nuclear Information System (INIS)

Wu, Hua-Yi; Wang, Hai-Bo; Liu, Xin-Hua; Li, Jian-Hui; Yang, Mei-Hua; Huang, Chuan-Jing; Weng, Wei-Zheng; Wan, Hui-Lin

2015-01-01

Graphical abstract: The addition of a small amount of Sm into VPO catalyst brought about great changes in its physicochemical properties such as surface area, surface morphology, phase composition and redox property, thus leading to a higher catalytic performance in the selective oxidation of n-butane to maleic anhydride, as compared to the undoped VPO catalyst. - Highlights: • The addition of Sm leads to great changes in the structure of VPO catalyst. • Sm improves performance of VPO for oxidation of n-butane to maleic anhydride. • Catalytic performance is closely related to structure of VPO catalyst. - Abstract: A series of samarium-modified vanadium phosphate catalysts were prepared and studied in selective oxidation of n-butane to maleic anhydride. The catalytic evaluation showed that Sm modification significantly increased the overall n-butane conversion and intrinsic activity. N 2 -adsorption, XRD, SEM, Raman, XPS, EPR and H 2 -TPR techniques were used to investigate the intrinsic difference among these catalysts. The results revealed that the addition of Sm to VPO catalyst can increase the surface area of the catalyst, lead to a significant change in catalyst morphology from plate-like structure into rosette-shape clusters, and largely promote the formation of (VO) 2 P 2 O 7 . All of these were related to the different catalytic performance of Sm-doped and undoped VPO catalysts. The roles of the different VOPO 4 phases and the influence of Sm were also described and discussed

Permanganate oxidation of sulfur compounds to prevent poisoning of Pd catalysts in water treatment processes.

Science.gov (United States)

Angeles-Wedler, Dalia; Mackenzie, Katrin; Kopinke, Frank-Dieter

2008-08-01

The practical application of Pd-catalyzed water treatment processes is impeded by catalyst poisoning by reduced sulfur compounds (RSCs). In this study, the potential of permanganate as a selective oxidant for the removal of microbially generated RSCs in water and as a regeneration agent for S-poisoned catalysts was evaluated. Hydrodechlorination using Pd/Al2O3 was carried out as a probe reaction in permanganate-pretreated water. The activity of the Pd catalysts in the successfully pretreated reaction medium was similar to that in deionized water. The catalyst showed no deactivation behavior in the presence of permanganate at a concentration level or = 0.08 mM, a significant but temporary inhibition of the catalytic dechlorination was observed. Unprotected Pd/Al2O3, which had been completely poisoned by sulfide, was reactivated by a combined treatment with permanganate and hydrazine. However, the anthropogenic water pollutants thiophene and carbon disulfide were resistant against permanganate. Together with the preoxidation of catalyst poisons, hydrophobic protection of the catalysts was studied. Pd/zeolite and various hydrophobically coated catalysts showed a higher stability against ionic poisons and permanganate than the uncoated catalyst. By means of a combination of oxidative water pretreatment and hydrophobic catalyst protection, we provide a new tool to harness the potential of Pd-catalyzed hydrodehalogenation for the treatment of real waters.

Highly Stable and Active Catalyst for Sabatier Reactions

Science.gov (United States)

Hu, Jianli; Brooks, Kriston P.

2012-01-01

Highly active Ru/TiO2 catalysts for Sabatier reaction have been developed. The catalysts have shown to be stable under repeated shutting down/startup conditions. When the Ru/TiO2 catalyst is coated on the engineered substrate Fe-CrAlY felt, activity enhancement is more than doubled when compared with an identically prepared engineered catalyst made from commercial Degussa catalyst. Also, bimetallic Ru-Rh/TiO2 catalysts show high activity at high throughput.

Production of perovskite catalysts on ceramic monoliths with nanoparticles for dual fuel system automobiles

International Nuclear Information System (INIS)

Khanfekr, A.; Arzani, K.; Nemati, A.; Hosseini, M.

2009-01-01

(Lanthanum, Cerium)(Iron, Manganese, Cobalt, Palladium)(Oxygen) 3 ,-Perovskite catalyst was prepared by the citrate route and deposited on ceramic monoliths via dip coating procedure. The catalyst was applied on a car with X U 7 motors and the amount of emission was monitored with vehicle emission test systems in Sapco company. The results were compared with the imported catalyst with noble metals such as Palladium, Platinum and Rhodium by Iran Khodro company based on the Euro III standards. The catalysts were characterized by specific surface area measurements, scanning electron microscopy, X-ray diffraction, line scan and map. In the results, obtained in the home made sample, the amount of carbon monoxide, nitrogen oxides and hydrocarbons were lower than imported catalyst with Iran Khodro company with nobel metals. The illustration shows nano particles size on coat. The microstructure evaluation showed that the improved properties can be related to the existence of nano particles on coating

Evaluation of nutritional screening tools for patients scheduled for cardiac surgery.

Science.gov (United States)

Lomivorotov, Vladimir V; Efremov, Sergey M; Boboshko, Vladimir A; Nikolaev, Dmitry A; Vedernikov, Pavel E; Lomivorotov, Vladimir N; Karaskov, Alexander M

2013-02-01

The aim of this study was to assess the prognostic value of different nutritional screening tools in patients undergoing cardiopulmonary bypass with regard to an adverse clinical course. This prospective cohort study analyzed 894 adult patients who underwent cardiopulmonary bypass. Patients were screened using four nutritional screening tools: Nutritional Risk Screening 2002 (NRS-2002), the Malnutrition Universal Screening Tool (MUST), the Mini-Nutritional Assessment (MNA), and the Short Nutritional Assessment Questionnaire (SNAQ). Nutritional status was assessed using the Subjective Global Assessment. In-hospital mortality, postoperative complications, length of stay in the intensive care unit, and length of hospitalization were analyzed. The sensitivities of the SNAQ, MUST, and NRS-2002 to detect the malnutrition confirmed by the Subjective Global Assessment were 91.5%, 97.9%, and 38.3%, respectively, and the MNA showed a sensitivity of 81.8% for the elderly. Malnutrition detected by the SNAQ, MUST, and NRS-2002 was associated with postoperative complications (odds ratios [ORs] 1.75, 1.98, and 1.82, respectively) and a stay in the intensive care unit longer than 2 d (ORs 1.46, 1.56, and 2.8). Malnutrition as detected by the SNAQ and MUST was also associated with prolonged hospitalization (ORs 1.49 and 1.59). According to multivariate logistic regression analysis, postoperative complications were independently predicted by the European System for Cardiac Operative Risk Evaluation (OR 1.1, P nutritional therapy would improve the outcome in malnourished patients needs to be studied. Copyright © 2013 Elsevier Inc. All rights reserved.

Co-Zn-Al based hydrotalcites as catalysts for Fischer-Tropsch process

Energy Technology Data Exchange (ETDEWEB)

Bianchi, C.L.; Pirola, C.; Boffito, D.C.; Di Fronzo, A. [Univ. degli Studi di Milano (Italy). Dipt. di Chimica Fisica ed Elettrochimica; Di Michele, A. [Univ. degli Studi di Perugia (Italy). Dipt. di Fisica; Vivani, R.; Nocchetti, M.; Bastianini, M.; Gatto, S. [Univ. degli Studi di Perugia (Italy). Dipt. di Chimica

2011-07-01

Co-Zn-Al based hydrotalcites have been investigated as catalysts for the well-known Fischer- Tropsch synthesis. A series of ternary hydrotalcites in nitrate form was prepared with the urea method in order to obtain active catalysts for the above mentioned process. The thermal activation at 350 C gives raise to finely dispersed metallic Co on the mixed oxides, so resulting in retaining the metal distribution of the parent compounds. An optimization study concerning the amount of cobalt of the prepared catalysts (range 15-70% mol, metal based) and the reaction temperature (220-260 C) is reported. All the samples have been fully characterized (BET, ICP-OES, XRPD, TG-DTA, FT-IR, SEM and TEM) and tested in a laboratory pilot plant. Tests to evaluate the stability of these materials were carried out in stressed conditions concerning both the activation and the operating temperatures and pressures (up to 350 C and 2.0 MPa). The obtained results suggest the possibility of using synthetic hydrotalcites as suitable Co-based catalysts for the Fischer-Tropsch synthesis. (orig.)

Biodiesel production using calcium manganese oxide as catalyst and different raw materials

International Nuclear Information System (INIS)

Dias, Joana Maia; Conceição Machado Alvim-Ferraz, Maria; Fonseca Almeida, Manuel; Méndez Díaz, José Diego; Sánchez Polo, Manuel; Rivera Utrilla, José

2013-01-01

Highlights: ► Biodiesel production using a calcium manganese oxide catalyst was studied. ► The active specie was Ca 0.9 Mn 0.1 O and its deactivation occurred by hydration. ► The studied catalyst presented lower activation temperature than CaO. ► Biodiesel production and quality using different raw materials is reported. ► Compared to the conventional process, biodiesel water content improved. - Abstract: The use of heterogeneous catalysts for biodiesel production aims to simplify the production process as well as to reduce purification costs and related environmental impacts. Calcium manganese oxide was recently identified by the authors as an interesting heterogeneous catalyst for biodiesel production from animal fat; however, the difference between this and other catalysts, the catalyst activation/deactivation mechanisms, its behaviour in the synthesis using different raw materials as well as the impacts of its use on product quality remained unclear. Therefore, the present work: (i) compared biodiesel production using calcium manganese oxide and other catalysts (CaO and NaOH); (ii) studied the reasons leading to activation/deactivation of the heterogeneous catalyst; (iii) analysed biodiesel heterogeneous synthesis using calcium manganese oxide and different raw materials (lard, waste frying oil and a mixture); and (iv) evaluated raw material and catalyst impact on the product quality. Considering the use of different catalysts, the results showed that, after 8 h of reaction, product purity was similar using the different catalysts, being 92.5 wt.% using both NaOH and calcium manganese oxide and 93.8 wt.% using CaO. The active species of the heterogeneous catalysts were CaO, in the case of calcinated calcium carbonate, and Ca 0.9 Mn 0.1 O, in the case of calcinated calcium manganese oxide. Because the deactivating species were different for both catalysts, the calcium manganese oxide required lower activation temperature, which should be an advantage

Development of a polymer catalyst for HANARO detritiation

International Nuclear Information System (INIS)

Chung, H.; Kang, H.S.; Paek, S.W.; Yoo, J.H.; Shon, S.H.; Kim, K.R.; Lee, S.H.; Ahn, D.H.; Lee, H.S.

1998-01-01

The use of heavy water as a reflector in HANARO results in the continuous exposure of deuterium oxide to neutron flux. Substantial quantities of tritium are generated by neutron activation of deuterium in the reflector. Airborne emissions and staff internal radiation doses could be caused by tritiated heavy water escaping from the system. A detritiation facility is thought to be effective in reducing the overall radiological impact. The detritiation process may consist of a catalytic exchange in the front-end and a cryogenic deuterium distillation section. In this paper, the catalyst manufacturing and its performance evaluation technology was presented. The waterproof polymer catalyst has a specific surface area larger than 400m 2 /g. It showed a high reaction rate in the hydrogen isotope exchange reaction. (author)

PET-modified red mud as catalysts for oxidative desulfurization reactions.

Science.gov (United States)

do Prado, Nayara T; Heitmann, Ana P; Mansur, Herman S; Mansur, Alexandra A; Oliveira, Luiz C A; de Castro, Cinthia S

2017-07-01

This work describes the synthesis of catalysts based on red mud/polyethylene terephthalate (PET) composites and their subsequent heat treatment under N 2 atmosphere. The materials were characterized by scanning electron microscopy (SEM), temperature programmed reduction (TPR), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric (TG) analysis and N 2 adsorption/desorption. The catalysts were evaluated in the oxidative desulfurization reaction of dibenzothiophene (DBT) in a biphasic system. The results indicated that the PET impregnation on red mud increased the affinity of the catalyst with the nonpolar phase (fuel), in which the contaminant was dissolved, allowing a higher conversion (up to 80%) and selectivity to the corresponding dibenzothiophene sulfone. The sulfone compound is more polar than DBT and diffused into the polar solvent as indicated by the data obtained via gas chromatography-mass spectrometry (GC-MS). Copyright © 2017. Published by Elsevier B.V.

Active carbon catalyst for heavy oil upgrading

Energy Technology Data Exchange (ETDEWEB)

Fukuyama, Hidetsugu; Terai, Satoshi [Technology Research Center, Toyo Engineering Corporation, 1818 Azafujimi, Togo, Mobara-shi, Chiba 297-00017 (Japan); Uchida, Masayuki [Business Planning and Exploring Department, Overseas Business Development and Marketing Division, Toyo Engineering Corporation, 2-8-1 Akanehama, Narashino-shi, Chiba 275-0024 (Japan); Cano, Jose L.; Ancheyta, Jorge [Maya Crude Treatment Project, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, Mexico D.F. 07730 (Mexico)

2004-11-24

The active carbon (AC) catalyst was studied by hydrocracking of Middle Eastern vacuum residue (VR) for heavy oil upgrading. It was observed that the active carbon has the affinity to heavy hydrocarbon compounds and adsorption selectivity to asphaltenes, and exhibits better ability to restrict the coke formation during the hydrocracking reaction of VR. The mesopore of active carbon was thought to play an important role for effective conversion of heavy hydrocarbon compounds into lighter fractions restricting carbon formation. The performance of the AC catalyst was examined by continuous hydrocracking by CSTR for the removal of such impurities as sulfur and heavy metals (nickel and vanadium), which are mostly concentrated in the asphaltenes. The AC catalyst was confirmed to be very effective for the removal of heavy metals from Middle Eastern VR, Maya/Istmo VR and Maya VR. The extruded AC catalysts were produced by industrial manufacturing method. The application test of the extruded AC catalyst for ebullating-bed reactor as one of the commercially applicable reactors was carried out at the ebullating-bed pilot plant for 500h. The ebullition of the extruded AC catalyst was successfully traced and confirmed by existing {gamma}-ray density meter. The extruded AC catalyst showed stable performance with less sediment formation at an equivalent conversion by conventional alumina catalyst at commercial ebullating-bed unit. The degradation of the AC catalyst at the aging test was observed to be less than that of the conventional alumina catalyst. Thus, the AC catalyst was confirmed to be effective and suitable for upgrading of heavy oil, especially such heavy oils as Maya, which contains much heavy metals.

Reactivation of a tin oxide-containing catalyst

Science.gov (United States)

Upchurch, Billy T. (Inventor); Miller, Irvin M. (Inventor); Brown, Kenneth G. (Inventor); Hess, Robert V. (Inventor); Schryer, David R. (Inventor); Sidney, Barry D. (Inventor); Wood, George M. (Inventor); Paulin, Patricia A. (Inventor)

1989-01-01

A method for the reactivation of a tin oxide-containing catalyst of a CO.sub.2 laser is provided. First, the catalyst is pretreated by a standard procedure. When the catalyst experiences diminished activity during usage, the heated zone surrounding the catalyst is raised to a temperature which is the operating temperature of the laser and 400.degree. C. for approximately one hour. The catalyst is exposed to the same laser gas mixture during this period. The temperature of the heated zone is then lowered to the operating temperature of the CO.sub.2 laser.

Prospective evaluation of cinefluoroscopy and chest radiography for Riata lead defects: implications for future lead screening.

Science.gov (United States)

Lorvidhaya, Peem; Mendoza, Ivan; Sehli, Sharmila; Atalay, Michael K; Kim, Michael H

2013-11-01

Lead insulation defects with externalization of the conductors exist in Riata defibrillator leads. Cinefluoroscopy is currently the gold standard to detect such defects. Prospective evaluation of alternative screening options such as chest radiography (CXR), which has been recommended by the FDA, is not well described. Patients with Riata leads underwent cinefluoroscopy, CXR, and device interrogation. Leads were classified as abnormal (clear cable separation), borderline, or normal by independent evaluation of cinefluoroscopy and CXR. CXR evaluation was done in two ways as follows: (1) routine CXR read by daily staff radiologists for lead screening and (2) CXR evaluation by a radiologist educated about the lead defect. One hundred two patients were evaluated at our institution. Cinefluoroscopy showed externalized conductors in 33 patients (32 %). Twenty-five of 33 patients (76 %) who had abnormal cinefluoroscopic findings had abnormal CXR findings on blinded review by the educated radiologist. All 25 patients with abnormal CXR had abnormal findings on cinefluoroscopy. Daily staff radiologists without direct education other than prompts for lead screening detected CXR abnormalities in only 8 out of 102 (8 %) cases. Cinefluoroscopy appears to be more sensitive than CXR for the detection of Riata cable extrusion. Interpretation of CXR by a radiologist with education in lead defects correlates highly with cinefluoroscopy with very high specificity. Depending on available resources for screening, CXR may be a reasonable alternative to cinefluoroscopy. Multidisciplinary collaboration across specialties (radiology and electrophysiology) can lead to improved diagnostic capability and thus the potential for enhanced quality of care.

Synthesis and characterization of catalysts for the selective transformation of biomass-derived materials

Science.gov (United States)

Ghampson, Isaac Tyrone

The experimental work in this thesis focuses on generating catalysts for two intermediate processes related to the thermal conversion of lignocellulosic biomass: the synthesis and characterization of mesoporous silica supported cobalt catalysts for the Fischer-Tropsch reaction, and an exploration of the reactivity of bulk and supported molybdenum-based nitride catalysts for the hydrodeoxygenation (HDO) of guaiacol, a lignin model compound. The first section of the work details the synthesis of a series of silica-supported cobalt Fischer-Tropsch catalysts with pore diameters ranging from 2-23 nm. Detailed X-ray diffraction measurements were used to determine the composition and particle diameters of the metal fraction, analyzed as a three-phase system containing Cofcc, Cohcp and CoO particles. Catalyst properties were determined at three stages in catalyst history: (1) after the initial calcination step to thermally decompose the catalyst precursor into Co3O4, (2) after the hydrogen reduction step to activate the catalyst to Co and (3) after the FT reaction. From the study, it was observed that larger pore diameters supported higher turnover frequency; smaller pore diameters yielded larger mole fraction of CoO; XRD on post-reduction and post-FTS catalyst samples indicated significant changes in dispersivity after reduction. In the next section, the catalytic behaviors of unsupported, activated carbon-, alumina-, and SBA-15 mesoporous silica-supported molybdenum nitride catalysts were evaluated for the hydrodeoxygenation of guaiacol (2-methoxy phenol) at 300°C and 5 MPa. The nitride catalysts were prepared by thermal decomposition of bulk and supported ammonium heptamolybdate to form MoO 3 followed by nitridation in either flowing ammonia or a nitrogen/hydrogen mixture. The catalytic properties were strongly affected by the nitriding and purging treatment as well as the physical and chemical properties of support. The overall reaction was influenced by the

Characterization and performances of cobalt-tungsten and molybdenum-tungsten carbides as anode catalyst for PEFC

International Nuclear Information System (INIS)

Izhar, Shamsul; Yoshida, Michiko; Nagai, Masatoshi

2009-01-01

The preparation of carbon-supported cobalt-tungsten and molybdenum-tungsten carbides and their activity as an anode catalyst for a polymer electrolyte fuel cell were investigated. The electrocatalytic activity for the hydrogen oxidation reaction over the catalysts was evaluated using a single-stack fuel cell and a rotating disk electrode. The characterization of the catalysts was performed by XRD, temperature-programmed carburization, temperature-programmed reduction and X-ray photoelectron spectroscopy. The maximum power densities of the 30 wt% 873 K-carburized cobalt-tungsten and molybdenum-tungsten mixed with Ketjen carbon (cobalt-tungsten carbide (CoWC)/Ketjen black (KB) and molybdenum-tungsten carbide (MoWC)/KB) were 15.7 and 12.0 mW cm -2 , respectively, which were 14 and 11%, compared to the in-house membrane electrode assembly (MEA) prepared from a 20 wt% Pt/C catalyst. The CoWC/KB catalyst exhibited the highest maximum power density compared to the MoWC/KB and WC/KB catalysts. The 873 K-carburized CoW/KB catalyst formed the oxycarbided and/or carbided CoW that are responsible for the excellent hydrogen oxygen reaction

In situ Transmission Electron Microscopy of catalyst sintering

DEFF Research Database (Denmark)

DeLaRiva, Andrew T.; Hansen, Thomas Willum; Challa, Sivakumar R.

2013-01-01

Recent advancements in the field of electron microscopy, such as aberration correctors, have now been integrated into Environmental Transmission Electron Microscopes (TEMs), making it possible to study the behavior of supported metal catalysts under operating conditions at atomic resolution. Here......, we focus on in situ electron microscopy studies of catalysts that shed light on the mechanistic aspects of catalyst sintering. Catalyst sintering is an important mechanism for activity loss, especially for catalysts that operate at elevated temperatures. Literature from the past decade is reviewed...... along with our recent in situ TEM studies on the sintering of Ni/MgAl2O4 catalysts. These results suggest that the rapid loss of catalyst activity in the earliest stages of catalyst sintering could result from Ostwald ripening rather than through particle migration and coalescence. The smallest...

Catalyst for hydrocarbon conversion

International Nuclear Information System (INIS)

Duhaut, P.; Miquel, J.

1975-01-01

A description is given for a catalyst and process for hydrocarbon conversions, e.g., reforming. The catalyst contains an alumina carrier, platinum, iridium, at least one metal selected from uranium, vanadium, and gallium, and optionally halogen in the form of metal halide of one of the aforesaid components. (U.S.)

Development of GREET Catalyst Module

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States); Benavides, Pahola T. [Argonne National Lab. (ANL), Argonne, IL (United States); Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States)

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.

The Monte Carlo evaluation of noise and resolution properties of granular phosphor screens

International Nuclear Information System (INIS)

Liaparinos, P F; Kandarakis, I S

2009-01-01

The imaging performance of phosphor screens, used as x-ray detectors in diagnostic medical imaging systems, is affected by their both noise and resolution properties. Amplification and blurring processes are due to a sequence of conversion stages within the screen which contribute to fluctuations in the number and spatial distribution of the optical quanta recorded by the optical detector (e.g. film, television camera, CCD, etc). The purpose of this paper is to investigate the stochastic noise arising from granularity as well as the variation of spatial resolution of granular fluorescent screens in terms of the detector's structure. Using a custom-validated Monte Carlo model, the parameters of interest were evaluated for the widely used Gd 2 O 2 S:Tb phosphor material. We have studied the variations of (i) the modulation transfer function, (ii) the Swank factor and (iii) the zero-frequency detective quantum efficiency (DQE), under several conditions employed in conventional and digital mammography and radiology. Several evaluations are provided for the imaging metrics as a function of the x-ray energy (18 keV, 49 keV and 51 keV), phosphor coating weight (20 mg cm -2 , 34 mg cm -2 and 60 mg cm -2 ), grain size (from 4 μm up to 13 μm) and packing density (from 50% up to 85%). It was found that screens of high packing density can combine high zero-frequency DQE with improved resolution properties. For a digital mammographic imaging system (34 mg cm -2 , 18 keV), a packing density of 85% can improve the spatial resolution of the screen by 1.6 cycles mm -1 in comparison to that of 50% packing density. Similarly, for radiographic cases (60 mg cm -2 , 49 keV), the spatial resolution can be improved by 1.7 cycles mm -1 . The aforementioned findings provide the resolution benefits of using high packing density screens.

Novel non-platinum metal catalyst material

DEFF Research Database (Denmark)

2014-01-01

The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

UTILIZATION OF CASSAVA WASTE IN THE PRODUCTION OF PLYWOOD ADHESIVE EKSTENDER WITH DEXTRIN (WITH ACID CATALYST

Directory of Open Access Journals (Sweden)

Piyantina Rukmini

2017-10-01

Full Text Available Abstract- Require of manihot Esculinta Crantz in Indonesia rises in every year as growth of Indonesian people, bioethanol industry,and animal food. Raw material that use in this research is cassava wastes. This research aimed to know the utilization of cassava waste, the optimum condition process of dextrin, and to know the variable that influent the utilization of cassava waste in the production of adhesive ekstender ( catalyst concentration and time. The dekstrin process need beaker glass, stirrer, electric stove with oilbatch heater, thermometer, screening 80 mesh. Cassava wastes that keep on several days is burned without water at 800 C for 1 hours. Then drops acid catalyst ion the beaker glass with different concentration. Then the temperature is raised until 1100C for 1 hour. After the drying process, make it cool then screen it in to screener 80 mesh. The results show that on the higher concentration of acid, dextrin will get on the higher concentration. At the certain concentration of acid, dekstrin will not get in the high concentration. Maximum efficiency of the concentration of acid is 0,8 N. Keeping long day for cassava waste can make lower the concentration of dextrin. The best keeping day is the first day until four day.

UTILIZATION OF CASSAVA WASTE IN THE PRODUCTION OF PLYWOOD ADHESIVE EKSTENDER WITH DEXTRIN (WITH ACID CATALYST

Directory of Open Access Journals (Sweden)

Piyantina Rukmini

2017-10-01

Full Text Available Require of manihot Esculinta Crantz in Indonesia rises in every year as growth of Indonesian people, bioethanol industry,and animal food. Raw material that use in this research is cassava wastes. This research aimed to know the utilization of cassava waste, the optimum condition process of dextrin, and to know the variable that influent the utilization of cassava waste in the production of adhesive ekstender ( catalyst concentration and time. The dekstrin process need beaker glass, stirrer, electric stove with oilbatch heater, thermometer, screening 80 mesh. Cassava wastes that keep on several days is burned without water at 800 C for 1 hours. Then drops acid catalyst ion the beaker glass with different concentration. Then the temperature is raised until 1100C for 1 hour. After the drying process, make it cool then screen it in to screener 80 mesh. The results show that on the higher concentration of acid, dextrin will get on the higher concentration. At the certain concentration of acid, dekstrin will not get in the high concentration. Maximum efficiency of the concentration of acid is 0,8 N. Keeping long day for cassava waste can make lower the concentration of dextrin. The best keeping day is the first day until four day.

Removal of free fatty acid in Palm Fatty Acid Distillate using sulfonated carbon catalyst derived from biomass wastefor biodiesel production

Science.gov (United States)

Hidayat, Arif; Rochmadi; Wijaya, Karna; Budiman, Arief

2016-01-01

In this research, the esterification of PFAD using the sulfonatedcoconut shell biochar catalyst was studied. Carbon solid catalysts were prepared by a sulfonation of carbonized coconut shells. The performances of the catalysts were evaluated in terms of the reaction temperatures, the molar ratios of methanol to PFAD, the catalyst loading and the reaction times. The reusability of the solid acid carbon catalysts was also studied in this work. The results indicated that the FFA conversion was significantly increased with increasing catalyst loading and reaction times. It can be concluded that the optimal conditions were an PFAD to methanol molar ratio of 1:12, the amount of catalyst of 10%w, and reaction temperature of 60oC.At this optimum condition, the conversion to biodieselreached 88%.

Chromium–tungsten–titanium mixed oxides solid catalyst for fatty acid methyl ester synthesis from palm fatty acid distillate

International Nuclear Information System (INIS)

Wan, Zuraida; Hameed, B.H.

2014-01-01

Highlights: • Chromium–tungsten–titanium mixed oxides as solid catalyst. • Catalyst used for esterification of palm fatty acid distillate to methyl esters. • The maximum methyl ester content is 83%. • Catalyst has shown good activity and can be recycled for 4 times. - Abstract: Chromium–tungsten–titanium mixed oxides solid catalysts were prepared and evaluated in the esterification of palm fatty acid distillate (PFAD) to produce fatty acid methyl ester (FAME). Esterification was conducted in a batch reactor at 110–200 °C temperature ranges. The catalysts were characterized by several techniques such as BET, TEM, FTIR, TGA, XRD, EDX and SEM. The treatment conditions during catalyst preparation, effect of reaction parameters, leaching of the active species and the recycled use of the catalyst were investigated. The catalyst with formula CrWTiO 2 was found to be the most active with maximum FAME content of 83% obtained at best reaction conditions of 170 °C for 3 h, 2:1 (methanol to oil molar ratio) and 2 wt.% catalyst dosage. The catalyst can be recycled for 4 times. The results revealed CrWTiO 2 good potentials for use in esterification of high acid value oil

Evaluation of a fluorescence-based method for antibabesial drug screening.

Science.gov (United States)

Guswanto, Azirwan; Sivakumar, Thillaiampalam; Rizk, Mohamed Abdo; Elsayed, Shimaa Abd Elsalam; Youssef, Mohamed Ahmed; ElSaid, ElSaid El Shirbini; Yokoyama, Naoaki; Igarashi, Ikuo

2014-08-01

In vitro evaluation of chemotherapeutic agents against Babesia and Theileria parasites has become routine, and the effectiveness of these chemicals is usually determined by comparing the parasitemia dynamics of untreated and treated parasites. Although microscopy is widely used to calculate parasitemia, several disadvantages are associated with this technique. The present study evaluated a fluorescence-based method using SYBR green I stain (SG I) to screen antibabesial agents in in vitro cultures of Babesia bovis. The linearity between relative fluorescence units (RFU) and parasitemia was found to be well correlated with a 0.9944 goodness-of-fit (r(2)) value. Subsequently, 50% inhibitory concentration (IC50) values were calculated for 3 antiprotozoan agents, diminazene aceturate, nimbolide, and gedunin, by this method. For diminazene aceturate and nimbolide, the IC(50)s determined by the fluorescence-based method (408 nM and 8.13 μM, respectively) and microscopy (400.3 nM and 9.4 μM, respectively) were in agreement. Furthermore, the IC50 of gedunin determined by the fluorescence-based method (19 μM) was similar to the recently described microscopy-based value (21.7 μM) for B. bovis. Additionally, the Z' factor (0.80 to 0.90), signal-to-noise (S/N) ratio (44.15 to 87.64), coefficient of variation at the maximum signal (%CVmax) (0.50 to 2.85), and coefficient of variation at the minimum signal (%CVmin) (1.23 to 2.21) calculated for the fluorescence method using diminazene aceturate were comparable to those previously determined in malaria research for this assay. These findings suggest that the fluorescence-based method might be useful for antibabesial drug screening and may have potential to be developed into a high-throughput screening (HTS) assay. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Development of high performance catalyst for off-gas treatment system in BWR

International Nuclear Information System (INIS)

Kawasaki, Toru; Kawabe, Kenichi; Maeda, Kiyomitsu; Matsubara, Hirofumi; Aizawa, Motohiro; Iizuka, Hidehiro; Kumagai, Naoki

2011-01-01

A high performance catalyst for off-gas treatment system in boiling water reactor (BWR) has been developed. The hydrogen concentration in the outlets of off-gas recombiners increased at several BWR plants in Japan. These phenomena were caused by deactivation of catalysts for the recombiners, and we assumed two types of deactivation mechanisms. The first cause was an increase of the amount of boehmite in the catalyst support due to alternation of the manufacturing process. The other cause was catalysts being poisoned by cyclic siloxanes that were introduced from the silicone sealant used in the upstream of the off-gas recombiners. The catalysts were manufactured by Pt adhering on alumina support. The conventional catalyst (CAT-A) used the aqueous solution of the chloroplatinic acid for adhesion of Pt. A dechlorination process by autoclave was applied to prevent the equipment at the downstream of the recombiners from stress corrosion cracking, but this process caused the support material to transform into boehmite. The boehmite-rich catalysts were deactivated more easily by organic silicon than gamma alumina-rich catalysts. Therefore, the CAT-A was replaced at many Japanese BWR plants by the improved catalyst (CAT-B), and their support was transformed into more stable gamma alumina by heating at 500degC. However, the siloxanes keep being detected in the off-gas though the source of siloxane had been removed and there still remain possibilities to deactivate the catalysts. Therefore, we have been developing high performance catalyst (CAT-C) that has higher activity and durability against poisoning. We investigated the properties of CAT-C by performance tests and instrumental analyses. The dependency of thermal output of nuclear reactor, and durability against siloxane poisoning were investigated. We found that CAT-C showed higher performance and better properties than CAT-B did. Moreover, we have been developing a modeling method to evaluate the hydrogen recombination

Superior mercury-free catalysts for acetylene hydrochlorination to VCM. Achieving high productivities and long catalyst life-time

Energy Technology Data Exchange (ETDEWEB)

Liebens, A.T.; Piccinini, M. [Solvay S.A., Bruxelles (Belgium)

2013-11-01

New mercury-free catalytic systems based on the use of ionic liquids (IL) and noble metals (e.g. Pd, Au) have been evaluated for the hydrochlorination reaction of acetylene to produce Vinyl Chloride Monomer (VCM). Two different approaches have been investigated: gas-liquid homogeneous catalytic systems in the presence of molten IL/Metal and heterogeneous gas-solid ones using solid materials. For the latter case, very positive results have been obtained using SILP-type catalysts (SILP: Supported Ionic Liquid Phase) where IL/Metal were deposited onto a solid mesoporous support. Remarkably, both systems display very high Space Time Yield (STY) and breakthrough life-time stability. No deactivation is observed even after 500 h on stream indicating the strong advantages of these new materials compared to most investigated Au/C supported systems. The development of heterogeneous catalysts was preferred as the scale-up of gas-liquid technology implies important CAPEX investments to convert current plants from gas-solid to gas-liquid equipment. (orig.)

Tungsten effect over co-hydrotalcite catalysts to produce hydrogen from bio-ethanol

Energy Technology Data Exchange (ETDEWEB)

Contreras, J.L.; Ortiz, M.A.; Luna, R.; Nuno, L. [Univ. Autonoma Metropolitana-Azcapozalco, Mexico City (Mexico). Dept. de Energia; Fuentes, G.A. [Univ. Autonoma Metropolitana-Iztapalapa, Mexico City (Mexico). Dept. de IPH; Salmones, J.; Zeifert, B. [Inst. Politecnico Nacional, Mexico City (Mexico); Vazquez, A. [Inst. Mexicano del Petroleo, Mexico City (Mexico)

2010-07-15

The use of bioethanol has been considered for generating hydrogen via catalytic reforming. The reaction of ethanol with stream is strongly endothermic and produces hydrogen (H{sub 2}) and carbon dioxide (CO{sub 2}). However, undesirable products such as carbon monoxide (CO) and methane (CH{sub 4}) may also form during the reaction. This paper reported on the newly found stabilization effect of tungsten over the Co-hydrotalcite catalysts to produce H{sub 2} from ethanol in steam reforming. The catalysts were characterized by nitrogen (N{sub 2}) physisorption (BET area), X-ray diffraction, Infrared, Raman and UV-vis spectroscopies. Catalytic evaluations were determined using a fixed bed reactor with a water/ethanol mol ratio of 4 at 450 degrees C. The tungsten concentration studied was from 0.5 to 3 wt percent. The intensity of crystalline reflections of the Co-hydrotalcite catalysts decreased as tungsten concentration increased. Infrared spectroscopy was used to determine the superficial chemical groups, notably -OH, H{sub 2}O, Al-OH, Mg-OH, W-O-W and CO{sub 3}{sup 2.} The highest H{sub 2} production and the best catalytic stability was found in catalysts with low tungsten. The smallest pore volume of this catalyst could be related with long residence times of ethanol in the pores. Tungsten promoted the conversion for the Co-hydrotalcite catalysts. The reaction products were H{sub 2}, CO{sub 2}, CH{sub 3}CHO, CH{sub 4} and C{sub 2}H{sub 4} and the catalysts did not produce CO. 33 refs., 2 tabs., 10 figs.

The Use of Economic Evaluation to Inform Newborn Screening Policy Decisions: The Washington State Experience.

Science.gov (United States)

Grosse, Scott D; Thompson, John D; Ding, Yao; Glass, Michael

2016-06-01

Newborn screening not only saves lives but can also yield net societal economic benefit, in addition to benefits such as improved quality of life to affected individuals and families. Calculations of net economic benefit from newborn screening include the monetary equivalent of avoided deaths and reductions in costs of care for complications associated with late-diagnosed individuals minus the additional costs of screening, diagnosis, and treatment associated with prompt diagnosis. Since 2001 the Washington State Department of Health has successfully implemented an approach to conducting evidence-based economic evaluations of disorders proposed for addition to the state-mandated newborn screening panel. Economic evaluations can inform policy decisions on the expansion of newborn screening panels. This article documents the use of cost-benefit models in Washington State as part of the rule-making process that resulted in the implementation of screening for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency and 4 other metabolic disorders in 2004, cystic fibrosis (CF) in 2006, 15 other metabolic disorders in 2008, and severe combined immune deficiency (SCID) in 2014. We reviewed Washington State Department of Health internal reports and spreadsheet models of expected net societal benefit of adding disorders to the state newborn screening panel. We summarize the assumptions and findings for 2 models (MCAD and CF) and discuss them in relation to findings in the peer-reviewed literature. The MCAD model projected a benefit-cost ratio of 3.4 to 1 based on assumptions of a 20.0 percentage point reduction in infant mortality and a 13.9 percentage point reduction in serious developmental disability. The CF model projected a benefit-cost ratio of 4.0-5.4 to 1 for a discount rate of 3%-4% and a plausible range of 1-2 percentage point reductions in deaths up to age 10 years. The Washington State cost-benefit models of newborn screening were broadly consistent with peer

N2O Decomposition over Cu–Zn/γ–Al2O3 Catalysts

Directory of Open Access Journals (Sweden)

Runhu Zhang

2016-12-01

Full Text Available Cu–Zn/γ–Al2O3 catalysts were prepared by the impregnation method. Catalytic activity was evaluated for N2O decomposition in a fixed bed reactor. The fresh and used catalysts were characterized by several techniques such as BET surface area, X-ray diffraction (XRD, and scanning electron microscopy (SEM. The Cu–Zn/γ–Al2O3 catalysts exhibit high activity and stability for N2O decomposition in mixtures simulating real gas from adipic acid production, containing N2O, O2, NO, CO2, and CO. Over the Cu–Zn/γ–Al2O3 catalysts, 100% of N2O conversion was obtained at about 601 °C at a gas hourly space velocity (GHSV of 7200 h−1. Cu–Zn/γ–Al2O3 catalysts also exhibited considerably good durability, and no obvious activity loss was observed in the 100 h stability test. The Cu–Zn/γ–Al2O3 catalysts are promising for the abatement of this powerful greenhouse gas in the chemical industry, particularly in adipic acid production.

Palm Frond and Spikelet as Environmentally Benign Alternative Solid Acid Catalysts for Biodiesel Production

Directory of Open Access Journals (Sweden)

Yahaya Muhammad Sani

2015-04-01

Full Text Available A carbonization-sulfonation method was utilized in synthesizing sulfonated mesoporous catalysts from palm tree biomass. Brunauer-Emmet-Teller (BET, powder X-ray diffraction (XRD, energy dispersive X-ray (EDX, and field emission scanning emission microscopy (FE-SEM analyses were used to evaluate the structural and textural properties of the catalysts. Further, Fourier transform infrared (FT-IR spectroscopy and titrimetric analyses measured the strong acid value and acidity distribution of the materials. These analyses indicated that the catalysts had large mesopore volume, large surface area, uniform pore size, and high acid density. The catalytic activity exhibited by esterifying used frying oil (UFO containing high (48% free fatty acid (FFA content further indicated these properties. All catalysts exhibited high activity, with sPTS/400 converting more than 98% FFA into fatty acid methyl esters (FAMEs. The catalyst exhibited the highest acid density, 1.2974 mmol/g, determined by NaOH titration. This is outstanding considering the lower reaction parameters of 5 h, 5:1 methanol-to-oil ratio, and a moderate temperature range between 100 and 200 °C. The study further illustrates the prospect of converting wastes into highly efficient, benign, and recyclable solid acid catalysts.

Development and Psychometric Evaluation of the Brief Adolescent Gambling Screen (BAGS).

Science.gov (United States)

Stinchfield, Randy; Wynne, Harold; Wiebe, Jamie; Tremblay, Joel

2017-01-01

The purpose of this study was to develop and evaluate the initial reliability, validity and classification accuracy of a new brief screen for adolescent problem gambling. The three-item Brief Adolescent Gambling Screen (BAGS) was derived from the nine-item Gambling Problem Severity Subscale (GPSS) of the Canadian Adolescent Gambling Inventory (CAGI) using a secondary analysis of existing CAGI data. The sample of 105 adolescents included 49 females and 56 males from Canada who completed the CAGI, a self-administered measure of DSM-IV diagnostic criteria for Pathological Gambling, and a clinician-administered diagnostic interview including the DSM-IV diagnostic criteria for Pathological Gambling (both of which were adapted to yield DSM-5 Gambling Disorder diagnosis). A stepwise multivariate discriminant function analysis selected three GPSS items as the best predictors of a diagnosis of Gambling Disorder. The BAGS demonstrated satisfactory estimates of reliability, validity and classification accuracy and was equivalent to the nine-item GPSS of the CAGI and the BAGS was more accurate than the SOGS-RA. The BAGS estimates of classification accuracy include hit rate = 0.95, sensitivity = 0.88, specificity = 0.98, false positive rate = 0.02, and false negative rate = 0.12. Since these classification estimates are preliminary, derived from a relatively small sample size, and based upon the same sample from which the items were selected, it will be important to cross-validate the BAGS with larger and more diverse samples. The BAGS should be evaluated for use as a screening tool in both clinical and school settings as well as epidemiological surveys.

Development and Psychometric Evaluation of the Brief Adolescent Gambling Screen (BAGS

Directory of Open Access Journals (Sweden)

Randy Stinchfield

2017-12-01

Full Text Available The purpose of this study was to develop and evaluate the initial reliability, validity and classification accuracy of a new brief screen for adolescent problem gambling. The three-item Brief Adolescent Gambling Screen (BAGS was derived from the nine-item Gambling Problem Severity Subscale (GPSS of the Canadian Adolescent Gambling Inventory (CAGI using a secondary analysis of existing CAGI data. The sample of 105 adolescents included 49 females and 56 males from Canada who completed the CAGI, a self-administered measure of DSM-IV diagnostic criteria for Pathological Gambling, and a clinician-administered diagnostic interview including the DSM-IV diagnostic criteria for Pathological Gambling (both of which were adapted to yield DSM-5 Gambling Disorder diagnosis. A stepwise multivariate discriminant function analysis selected three GPSS items as the best predictors of a diagnosis of Gambling Disorder. The BAGS demonstrated satisfactory estimates of reliability, validity and classification accuracy and was equivalent to the nine-item GPSS of the CAGI and the BAGS was more accurate than the SOGS-RA. The BAGS estimates of classification accuracy include hit rate = 0.95, sensitivity = 0.88, specificity = 0.98, false positive rate = 0.02, and false negative rate = 0.12. Since these classification estimates are preliminary, derived from a relatively small sample size, and based upon the same sample from which the items were selected, it will be important to cross-validate the BAGS with larger and more diverse samples. The BAGS should be evaluated for use as a screening tool in both clinical and school settings as well as epidemiological surveys.

A novel [Bmim]PW/HMS catalyst with high catalytic performance for the oxidative desulfurization process

Energy Technology Data Exchange (ETDEWEB)

Tang, Ling; Luo, Guangqing; Kang, Lihua; Zhu, Mingyuan; Dai, Bin [Shihezi University, Shihezi (China)

2013-02-15

To effectively reduce the sulfur content in model fuel, [Bmim]PW/HMS catalyst was synthesized through impregnating the hexagonal mesoporous silica (HMS) support by phosphotungstic acid (HPW) and ionic liquid [Bmim] HSO{sub 4}. Physical structure characterizations of the catalysts showed that HMS retained mesoporous structure, and [Bmim] PW was well dispersed on the support of HMS. The catalytic activity of the [Bmim]PW/HMS was evaluated in the oxidative desulfurization process, and the optimal reaction conditions including loading of the catalysts, reaction temperature, catalyst amount, O/S (H{sub 2}O{sub 2}/sulfur) molar ratio and agitation speed were investigated. Under the optimal reaction conditions, the conversion of benzothiophene (BT), dibenzothiophene (DBT) and 4, 6-dimethyldibenzothiophene (4, 6-DMDBT) could reach 79%, 98%, 88%, respectively.

A novel [Bmim]PW/HMS catalyst with high catalytic performance for the oxidative desulfurization process

International Nuclear Information System (INIS)

Tang, Ling; Luo, Guangqing; Kang, Lihua; Zhu, Mingyuan; Dai, Bin

2013-01-01

To effectively reduce the sulfur content in model fuel, [Bmim]PW/HMS catalyst was synthesized through impregnating the hexagonal mesoporous silica (HMS) support by phosphotungstic acid (HPW) and ionic liquid [Bmim] HSO 4 . Physical structure characterizations of the catalysts showed that HMS retained mesoporous structure, and [Bmim] PW was well dispersed on the support of HMS. The catalytic activity of the [Bmim]PW/HMS was evaluated in the oxidative desulfurization process, and the optimal reaction conditions including loading of the catalysts, reaction temperature, catalyst amount, O/S (H 2 O 2 /sulfur) molar ratio and agitation speed were investigated. Under the optimal reaction conditions, the conversion of benzothiophene (BT), dibenzothiophene (DBT) and 4, 6-dimethyldibenzothiophene (4, 6-DMDBT) could reach 79%, 98%, 88%, respectively

Upgrading pyrolysis bio-oil through hydrodeoxygenation (HDO) using non-sulfided Fe-Co/SiO2 catalyst

International Nuclear Information System (INIS)

Cheng, Shouyun; Wei, Lin; Julson, James; Rabnawaz, Muhammad

2017-01-01

Highlights: • Fe-Co/SiO 2 catalyst with medium acidity was more effective for bio-oil upgrading. • Co-loading of Fe and Co on SiO 2 support improved catalyst performance. • Catalyst showing the best catalytic activity had a Fe/Co mole ratio of 1. • Biofuel produced by Fe-Co(1)/SiO 2 had the higher hydrocarbons content at 22.44%. • The mechanism of bio-oil HDO on Fe-Co/SiO 2 catalysts is proposed. - Abstract: Hydrodeoxygenation (HDO) is an effective route to upgrade bio-oil to hydrocarbon bio-oil, but the development of efficient catalysts for bio-oil HDO still remains a challenge. In this study, non-sulfided Fe-Co/SiO 2 catalysts were used to upgrade bio-oil using HDO. A series of Fe-Co/SiO 2 catalysts with different Fe/Co mole ratios were prepared, characterized and evaluated. The Fe and/or Co loading did not change SiO 2 crystalline structure. The Fe and/or Co metals increased the amount and strength of Fe-Co/SiO 2 catalyst acidity. Physicochemical properties of upgraded bio-oils produced using Fe-Co/SiO 2 catalysts such as water content, total acid number, viscosity and higher heating values improved in comparison to raw bio-oil. Bimetallic Fe-Co/SiO 2 catalysts resulted in better HDO performance than monometallic Fe/SiO 2 or Co/SiO 2 catalysts. This was due to the synergistic effect of Fe and Co occurring on the SiO 2 support. Fe-Co/SiO 2 catalyst having medium amount of acidity was more effective for bio-oil upgrading. The highest hydrocarbons content produced using Fe-Co(1)/SiO 2 catalyst was 22.44%. The mechanism of bio-oil HDO on Fe-Co/SiO 2 catalysts is proposed.

Catalytic wet air oxidation of chlorophenols over supported ruthenium catalysts

International Nuclear Information System (INIS)

Li Ning; Descorme, Claude; Besson, Michele

2007-01-01

A series of noble metal (Pt, Pd, Ru) loaded zirconia catalysts were evaluated in the catalytic wet air oxidation (CWAO) of mono-chlorophenols (2-CP, 3-CP, 4-CP) under relatively mild reaction conditions. Among the investigated noble metals, Ru appeared to be the best to promote the CWAO of CPs as far as incipient-wetness impregnation was used to prepare all the catalysts. The position of the chlorine substitution on the aromatic ring was also shown to have a significant effect on the CP reactivity in the CWAO over 3 wt.% Ru/ZrO 2 . 2-CP was relatively easier to degradate compared to 3-CP and 4-CP. One reason could be the higher adsorption of 2-CP on the catalyst surface. Further investigations suggested that 3 wt.% Ru/ZrO 2 is a very efficient catalyst in the CWAO of 2-CP as far as high 2-CP conversion and TOC abatement could still be reached at even lower temperature (393 K) and lower total pressure (3 MPa). Additionally, the conversion of 2-CP was demonstrated to increase with the initial pH of the 2-CP solution. The dechlorination reaction is promoted at higher pH. In all cases, the adsorption of the reactants and the reaction intermediates was shown to play a major role. All parameters that would control the molecule speciation in solution or the catalyst surface properties would have a key effect

exchanged Mg-Al hydrotalcite catalyst