WorldCat Identities

Clark Atlanta University

Overview
Works: 152 works in 172 publications in 1 language and 2,742 library holdings
Genres: Periodicals  Catalogs  Conference proceedings 
Roles: Researcher
Classifications: E185.5, 909.0496005
Publication Timeline
Key
Publications about Clark Atlanta University Publications about Clark Atlanta University
Publications by Clark Atlanta University Publications by Clark Atlanta University
Most widely held works by Clark Atlanta University
Phylon ( )
in English and held by 1,513 WorldCat member libraries worldwide
Measuring food security in the Dominican Republic adaptation of the U.S. food security survey module ( )
1 edition published in 2008 in English and held by 169 WorldCat member libraries worldwide
The Status of Black Atlanta ( )
in English and held by 97 WorldCat member libraries worldwide
Chemically derived dense alumina-zirconia composites for improved mechanical and wear erosion properties final report for project no. NAG4-0011 ( Book )
1 edition published in 1998 in English and held by 77 WorldCat member libraries worldwide
In the eye of the muses : selections from the Clark Atlanta University art collection by Clark Atlanta University ( Book )
2 editions published in 2012 in English and held by 70 WorldCat member libraries worldwide
The status of Black Atlanta 1993 by Southern Center for Studies in Public Policy ( Book )
2 editions published in 1993 in English and held by 68 WorldCat member libraries worldwide
Proceedings of the American Society for Composites Eleventh Technical Conference : October 7-9, Omni Hotel at CNN, Atlanta, Georgia by American Society for Composites ( Book )
1 edition published in 1996 in English and held by 21 WorldCat member libraries worldwide
The Phylon quarterly ( )
in English and held by 8 WorldCat member libraries worldwide
Racing to save the planet environmental career opportunities for minorities ( Visual )
1 edition published in 1993 in English and held by 8 WorldCat member libraries worldwide
IMPROVED CATALYSTS FOR HEAVY OIL UPGRADING BASED ON ZEOLITE Y NANOPARTICLES ENCAPSULATED IN STABLE NANOPOROUS HOSTS ( )
1 edition published in 2004 in English and held by 5 WorldCat member libraries worldwide
The focus of this project is to improve the catalytic performance of zeolite Y for heavy petroleum hydrocracking by synthesizing nanoparticles of the zeolite ((almost equal to)20-30 nm) inside nanoporous silicate or aluminosilicate hosts of similar pore diameters. The encapsulated zeolite nanoparticles are expected to possess pores of reduced diffusional path lengths, hence hydrocarbon substrates will diffuse in, are converted and the products quickly diffused out. This is expected to prevent over-reaction, hence minimizing pore blockage and active sites deactivation. In this phase of the project, research activities were focused on refining procedures to: (a) improve the synthesis of ordered, high surface area nanoporous silica, such as SBA-15, with expanded pore size using trimethylbenzene as additive to the parent SBA-15 synthesis mixture; and (b) reduce the particle size of zeolite Y such that they can be effectively incorporated into the nanoporous silicas. The synthesis of high surface ordered nanoporous silica containing enlarged pores of diameter of 25 nm (larger than the standard size of 8.4 nm) using trimethylbenzene as a pore size expander was accomplished. The synthesis of zeolite Y nanoparticles with median pore size of approximately 50 nm (smaller than the 80 nm typically obtained with TMAOH) using combined TMABr/TMAOH as organic additives was also accomplished
A NEW CLASS OF MESOPOROUS ALUMINOPHOSPHATES FOR APPLICATION IN PERTOLEUM REFINING ( )
1 edition published in 2003 in English and held by 5 WorldCat member libraries worldwide
This project focuses on the synthesis of mesoporous aluminophosphate and aluminosilicates as catalysts for application in the conversion of large petroleum feedstock compounds to useful middle distillates and naphtha transportation fuels. Summarized herein, is our research progress for September 1, 2001 to August 31, 2002. The synthesis of aluminophosphates in the presence of nonionic surfactants and block co-polymers were explored over a wide range of synthesis variables such as temperature, Al/P ratio, pH and surfactants/polymer concentrations. In most cases, the resulting products were found to be amorphous. A partially ordered aluminophosphate mesophase was obtained in the presence of Brij 56 non-ionic surfactant. Further characterization to determine the phase type (e.g. hexagonal lamellar or cubic) of this product is pending. The amorphous nature of the products obtained using these classes of surfactants are in contrast to highly ordered aluminophosphates mesophases obtained in the presence of cationic quaternary ammonium surfactants, such as cetyltrimethylammonium detailed in a previous report. The synthesis of pure-silica and aluminosilicate mesophases of different type and quality were also conducted over a wide range of variables such as temperature, Si/Al ratio, pH and surfactants/polymer concentrations. However characterization of the phase type and quality of the materials produced is pending due to a severe and extended malfunction of the X-Ray Diffractometer. Nitrogen porosimetry of selected calcined samples showed various absorption isotherm with some samples showing type IV with a large step in the mesoporous range. Surface area of the samples varied and maximized at approximately 1000 m²/g, which is typically reported for materials of this type. Further characterization of the sample will be conducted following repair of the X-Ray Diffractometer
IMPROVED CATALYSTS FOR HEAVY OIL UPGRADING BASED ON ZEOLITE Y NANOPARTICLES ENCAPSULATED STABLE NANOPOROUS HOST ( )
1 edition published in 2005 in English and held by 5 WorldCat member libraries worldwide
The objectives of this project are to synthesis nanocrystals of highly acidic zeolite Y, encapsulate them within the channels of mesoporous (nanoporous) silicates or nanoporous organosilicates and evaluate the ''zeolite Y/Nanoporous host'' composites as catalysts for the upgrading of heavy petroleum feedstocks. Our results to date are summarized as follows. The synthesis of high surface ordered nanoporous silica of expanded pore diameter of 25 nm (larger than the standard size of 8.4 nm) using trimethylbenzene as a pore size expander was accomplished. The synthesis of zeolite Y nanoparticles with median pore size of approximately 50 nm (smaller than the 80 nm typically obtained with TMAOH) using combined TMABr/TMAOH as organic additives was also accomplished. The successful synthesis of zeoliteY/Nanoporous host composite materials by sequential combination of zeolite precursors and nanoporous material precursor mixtures was implied based on results from various characterization techniques such as X-Ray diffraction, infrared spectra, thermal analysis, porosimetry data. The resulting materials showed pore sizes up to 11 nm, and infrared band at 570 cm⁻¹ suggesting the presence of both phases. Work in the immediate future will be focused on the following three areas: (1) Further characterization of all-silica and aluminosilicate mesoporous materials with expanded pore sizes up to 30 nm will continue; (2) Research efforts to reduce the average particle size of zeolite nanoparticles down to 35-30 nm will continue; (3) Further synthesis of polymer-SBA15 nanocomposites will be conducted by changing the amount and chemistry of the zeolitic precursors added; and (4) Investigation on the catalytic properties of the materials using probe catalytic reactions (such as cumene cracking), followed by catalytic testing for heavy oil conversion
IMPROVED CATALYSTS FOR HEAVY OIL UPGRADING BASED ON ZEOLITE Y NANOPARTICLES ENCAPSULATED IN STABLE NANOPOROUS HOSTS ( )
1 edition published in 2003 in English and held by 5 WorldCat member libraries worldwide
The focus of this project is to improve the catalytic performance of zeolite Y for petroleum hydrocracking by synthesizing nanoparticles of the zeolite ({approx}20-25 nm) inside nanoporous silicate or aluminosilicate hosts. The encapsulated zeolite nanoparticles are expected to possess reduced diffusional path lengths, hence hydrocarbon substrates will diffuse in, are converted and the products quickly diffused out. This is expected to prevent over-reaction and the blocking of the zeolite pores and active sites will be minimized. In this phase of the project, procedures for the synthesis of ordered nanoporous silica, such as SBA-15, using block copolymers and nonionic surfactant were successful reproduced. Expansion of the pores sizes of the nanoporous silica using trimethylbenzene is suggested based on shift in the major X-Ray Diffraction peak in the products to lower 2 angles compared with the parent SBA-15 material. The synthesis of ordered nanoporous materials with aluminum incorporated in the predominantly silicate framework was attempted but is not yet successful, and the procedures needs will be repeated and modified as necessary. Nanoparticles of zeolite Y of particle sizes in the range 40 nm to 120 nm were synthesized in the presence of TMAOH as the particle size controlling additive
A NEW CLASS MESOPOROUS ALUMINOPHOSPHATES AS POTENTIAL CATALYSTS IN THE UPGRADING PETROLEUM FEEDSTOCKS ( )
1 edition published in 2005 in English and held by 5 WorldCat member libraries worldwide
A comprehensive investigation was conducted towards the synthesis and catalytic evaluation of high surface areas, uniform pore size, mesoporous aluminophosphates (AlPO₄) as potential catalysts for the upgrading of heavy petroleum feedstock, such as heavy crudes and petroleum residuum. The influence of several synthesis variables (including, the nature of the reactants, chemical composition of reaction mixtures, time and temperature) on the synthesis and physicochemical characteristics of the resulting products was explored. Phosphoric acid and three different aluminum sources, namely, aluminum hydroxide, aluminum isopropoxide and psuedobohemite alumina, were used as the inorganic precursors. Cetyltrimethylammonium chloride (C₁₆TACl) surfactant was used as charge compensating cation and structure directing agent in the surfactant-micellar-mediated synthesis pathway employed. Synthesis were conducted from reaction mixtures within the following typical molar composition range: xAl₂O₃:P₂O₅:yC₁₆TMACl: zTHMAOH: wH₂O, where x = 0.29-2.34, y = 0.24-0.98, z = 0.34-1.95, w = 86-700. Selected materials were evaluated for the conversion of isopropylbenzene (cumene) in order to understand the nature of any acid sites created. The synthesis products obtained depended strongly on the molar composition of the synthesis mixture. A lamellar (layered) phase was favored by synthesis mixtures comprised of low Al/P ratios (<0.33), low TMAOH content, high C₁₆TACl concentrations and high synthesis temperature (110 C). Formation of the desired hexagonal (tubular) phase was favored by higher Al/P ratios and TMAOH content, pH range between 8-10, low C₁₆TACl concentration and ambient temperature. The aluminum source had significant influence on the products obtained. With aluminum hydroxide (A1(OH)₃) as the hydroxide source, the resulting hexagonal phase in the ''as-synthesized'' form demonstrated well defined ordered mesoporous structure for synthesis mixtures of Al/P ratios in the range of 0.47-1.25, above which increasingly disordered products were observed. The products were however unstable to calcination in air above 400 C to remove the organic template, under which structural collapsed was observed. Products formed using pseudoboehmite alumina (catapal B), were more thermally stable than those formed with aluminum isopropoxide, though all products experienced some degree of structural collapsed on calcination and yielded micro- or micro-mesoporous materials ranging from low (<500 m²/g) to high surface areas (>500 m²/g) and pore sizes ranging from microporous (<1.5 nm) in some products to mesoporous (up to 3.6 nm) in other. Improvement in thermal stability was not observed when Mg and Co or bridging organic functional groups were incorporated with the mesoporous framework. The products showed negligible activity for the conversion of cumene at 300 C. Further research is necessary to investigate alternative synthesis strategies to strengthen and improve the thermal stabilities of these aluminophosphates
IMPROVED CATALYSTS FOR HEAVY OIL UPGRADING BASED ON ZEOLITE Y NANOPARTICLES ENCAPSULATED IN STABLE NANOPOROUS HOST ( )
1 edition published in 2005 in English and held by 5 WorldCat member libraries worldwide
Composite materials of SBA-15/zeolite Y were synthesized from zeolite Y precursor and a synthesis mixture of mesoporous silicate SBA-15 via a hydrothermal process in the presence of a slightly acidic media of pH 4-6 with 2M H₂SO₄. The SBA-15/ZY composites showed Type IV adsorption isotherms, narrow BJH average pore size distribution of 4.9 nm, surface areas up to 800 m²²g and pore volumes 1.03 cm³, all comparable to pure SBA-15 synthesized under similar conditions. Chemical analysis revealed Si/Al ratio down to 8.5 in the most aluminated sample, and ²⁷AlSS MAS NMR confirmed aluminum was in tetrahedral coordination. This method of introduction of Al in pure T{sub d} coordination is effective in comparison to other direct and post synthesis alumination methods. Bronsted acid sites were evident from a pyridinium peak at 1544 cm-1 in the FTIR spectrum after pyridine adsorption, and from NH₃ -TPD experiments. SBA-15/ZY composites showed significant catalytic activities for the dealkylation of isopropylbenzene to benzene and propene, similar to those of commercial zeolite Y. It was observed that higher conversion for catalysts synthesized with high amount of ZY precursor mixture added to the SBA-15. Over all the composites has shown good catalytic activity. Further studies will be focused on gaining a better understand the nature of the precursor, and to characterize and to locate the acid sites in the composite material. The composite will also be evaluated for heavy oil conversion to naphtha and middle distillates
TOWARDS A NEW CLASS OF MESOPOROUS MATERIALS FOR APPLICATIONS IN PETROLEUM REFINING ( )
1 edition published in 2005 in English and held by 5 WorldCat member libraries worldwide
This project focuses on the synthesis of mesoporous aluminophosphates, silicates and aluminosilicates as catalysts for applications in the conversion of large petroleum feedstock compounds to useful middle distillates and naphtha transportation fuels. Summarized herein is our research progress from September 1, 2003, to August 31, 2004. In previous reports it was demonstrated that mesoporous aluminophosphates with neutral framework (containing Al, P and O) could be synthesized, but their thermal stabilities were limited. In general, the materials' pore structure collapsed when calcined at 500-550 C in air or extracted in ethanol/HCl mixture to remove the surfactants, which were used as synthesis templates. New methods to improve the thermal stability of the materials needed to be explored. It was conceived that by adding divalent metals cations, such as Mg and Co, not only that the acid sites would be created by balancing the negatively charged framework (balanced by H), but the thermal stability of the materials would be improved. In addition, methods to facilitate the interaction of hydrocarbon substrates with acid sites within the mesoporous are also needed. One concept towards improving this was to incorporate organic functional groups within or attached to the otherwise purely inorganic aluminophosphate (containing Co or Mg) or aluminosilicate pore walls of the mesopores. In the last report we detailed that mesoporous organosilicates were synthesized using block copolymer under acid conditions containing silica and phenylene ( -C₆H₄₋. Materials prepared with phenylene group among the silica pore walls was found to be thermally stable up to 550 C which is almost 100 C higher than the temperature used for the mild hydrocracking of petroleum. It was also highlighted that this area was the subject of recent intense research activities by other researchers. Building on precedence of the last report and on the results of other researchers, we investigated the synthesis of a wide range of mesoporous silicates containing different organic functionalities within the pore walls (using -CH₂CH₂₋, simultaneously combined with additional organic functional groups extended within the mesopores and grafted through silicate linkages to the pore walls (including (SiO)₃-CH{sub n}SH, (SiO)₃-CH{sub n}NH (SiO)₃-CH{sub n}IM and (SiO)₃-CH{sub n}C₆H₄, X is imidazole) for use as potential acid catalysts in petroleum upgrading. Based on modifications to published procedures, we synthesized organic functionalized mesoporous organosilicates described above with surface area greater that 700 m²/g, pore volume> 0.73 cm³. The materials were stable to ethanolic extraction, but showed various degrees of thermal stability depending on the nature of the organic groups attached. We also investigated the synthesis of a wide range of mesoporous alumiophosphate containing Mg and Co in the matrix. Synthesis was also conducted on organic functionalized aluminophosphates containing similar organic functionalities described above. Syntheses of the phosphates was conducted in basic conditions with cationic surfactant, namely C₁₆H₃₃N(CH₃)Cl as templates. However, the structure of all the aluminophosphates appear to collapse when the template was removed by extraction or calcination. The catalytic testing phase of the project has commenced with the assembly of a microreactor interfaced with a gas chromatograph. Further research will be focused on use the microreactor to evaluate those potential mesoporous aluminosilicate and alumiophosphate catalyst materials which has maintained some stability, as detailed in this and previous reports, and will also be focused on investigating alternative synthesis approach to strengthen the thermal stability of the aluminophosphates
Hydrogen from biomass for urban transportation by William Boone ( Book )
1 edition published in 2008 in English and held by 5 WorldCat member libraries worldwide
An Integrated Hydrogen Producton-CO2 Capture Process from Fossil Fuel ( )
1 edition published in 2005 in English and held by 5 WorldCat member libraries worldwide
The major project objective is to determine the feasibility of using the char from coal and/or biomass pyrolysis, ammonia and CO2 emissions at smokestacks to produce clean hydrogen and a sequestered carbon fertilizer. During this work period, literature review has been completed. The project plan, design and test schedules were made on the basis of discussion with partner in experimental issues. Installation of pilot scale units was finished and major units tests were fully performed. Modification of the pyrolyzer, reformer and gas absorption tank have been done. Integration testing is performing recently. Lab scale tests have been performed. Field tests of char/fertilizer have been conducted. The experimental results are discussed in this paper
Alternative formulations of regenerable flue gas cleanup catalysts. Progress report, September 1, 1992--November 30, 1992 ( )
1 edition published in 1992 in English and held by 4 WorldCat member libraries worldwide
Lithium can be used with good effectiveness as a promoter for SO₂ adsorption on alumina due to its high basicity. The difficulty of depositing a layer on the surface of alumina must be overcome to achieve this goal. The x-ray diffraction studies indicate that the Mg precursor is well-dispersed on the alumina surface, and that the crystals formed, if any, are too small to be detected by the diffractometer. Further work must be done on the lithium-promoted samples to examine the dispersion on alumina
Alternative formulations of regenerable flue gas cleanup catalysts. Progress report, September 1, 1991--August 31, 1992 ( )
1 edition published in 1992 in English and held by 4 WorldCat member libraries worldwide
We have used non-aqueous impregnation techniques to prepare an aluminum oxide surface covered with a well-dispersed magnesium oxide layer using magnesium acetylacetonate dehydrate [Mg(acac)₂{sm_bullet}2H₂0] as a precursor. Using lithium acetylacetonate as a precursor, we have begun attempts to prepare a similarly well dispersed surface layer of lithium ''oxide.'' We have generated higher weight loadings of magnesium on alumina by using a Soxhlet extractor to dissolve the sparingly soluble Mg(acac)₂{sm_bullet}2H₂0 in methanol. With this device we are able to obtain loadings of MgO on the alumina up to 0.66 wt/wt%. The precursor samples were examined by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and our results indicate that the complex loses the water of hydration upon adsorption. It appears, however, that the initial form of the complex on the surface is as anhydrous crystallites. Heating the supported precursor under vacuum leads to ''melting'' of the crystals, which can be observed by DRIFTS. Decomposition of the precursor under nitrogen or air leads to very similar activity when adsorbing SO₂. SO₂ uptake appears to be independent of whether O₂ is Present in the gas stream or not. We have shown that SO₂ adsorption increases with Mg-loading on the impregnated aluminas, with 0.85 additional molecules Of SO₂ adsorbed for each additional Mg atom (or MgO molecule) on the surface. We have shown that non-aqueous impregnation leads to samples which are more efficient with regard to SO₂ uptake per magnesium atom than aqueous impregnation
 
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controlled identity Atlanta University

controlled identity Clark College

Atlanta University Center (Ga.) Clark Atlanta University
Clark University Atlanta, Ga
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English (45)
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