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2004

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Articles 1 - 30 of 51

Full-Text Articles in Chemical Engineering

My Life With Polymer Science: Scientific And Personal Memoirs, Otto Vogl Dec 2004

My Life With Polymer Science: Scientific And Personal Memoirs, Otto Vogl

Otto Vogl

My "life story" will begin with my formative years, my childhood and student days at the University of Vienna, including my dissertation. It will be followed by my teaching appointment as an Instructor at the II. Chemical Institute of the University of Vienna. The urge to see other lands, learn other languages and scientific methods led to the Wandering Years that brought me to the United States. After three years spent as a Research Associate at the University of Michigan and at Princeton University I spent more than 13 years in an industrial career at the Du Pont Company in …


Surface Structure Of Alkylsilylated Hzsm-5 As Phase-Boundary Catalyst, Hadi Nur, Yun Hau Ng, Mohd Nazlan Mohd Muhid, Halimaton Hamdan Nov 2004

Surface Structure Of Alkylsilylated Hzsm-5 As Phase-Boundary Catalyst, Hadi Nur, Yun Hau Ng, Mohd Nazlan Mohd Muhid, Halimaton Hamdan

Yun Hau Ng

The need for cleaner environment concerns motivates the development of more efficient catalytic system. Based on this consideration, recently a novel catalyst named "Phase-boundary catalyst", a bimodal amphiphilic solid catalyst, was proposed. It was demonstrated that the catalytic system containing phase-boundary catalyst required neither stirring to make an emulsion nor addition of a co-solvent to make a homogeneous solution to drive the reaction. The driving force that has prompted this paper is to investigate the surface structure of alkylsilylated HZSM-5 as phase-boundary catalyst. Temperature Programmed Desorption (TPD) of ammonia and, 13C and 29Si MAS NMR spectroscopy were used to elucidate …


Pictures From My Life With Polymer Science: Album 01, Otto Vogl Nov 2004

Pictures From My Life With Polymer Science: Album 01, Otto Vogl

Otto Vogl

No abstract provided.


Ordered Network Phases In Linear Poly(Isoprene-B-Styrene-B-Ethylene Oxide) Triblock Copolymers, Thomas H. Epps Iii, Eric W. Cochran, Travis S. Bailey, Ryan S. Waletzko, Cordell M. Hardy, Frank S. Bates Oct 2004

Ordered Network Phases In Linear Poly(Isoprene-B-Styrene-B-Ethylene Oxide) Triblock Copolymers, Thomas H. Epps Iii, Eric W. Cochran, Travis S. Bailey, Ryan S. Waletzko, Cordell M. Hardy, Frank S. Bates

Eric W. Cochran

The equilibrium phase behavior of 43 linear poly(isoprene-b-styrene-b- ethylene oxide) (ISO) triblock copolymer melts, with molecular weights that place these materials near the order-disorder transition, is reported. Ordered phase morphologies were characterized using small-angle X-ray scattering, transmission electron microscopy, dynamic mechanical spectroscopy, and static birefringence measurements. Interpretation of these results was aided by a modeling technique that facilitates resolution of reciprocal and real-space experimental data, leading to definitive three-dimensional morphological structures. Three distinct multiply continuous network morphologies are identified across a range of compositions between 0.1 ≤ f o ≤ 0.3, situated between two-domain and three-domain lamellae, where f o …


Pictures From My Life With Polymer Science: Album 02, Otto Vogl Oct 2004

Pictures From My Life With Polymer Science: Album 02, Otto Vogl

Otto Vogl

No abstract provided.


Pictures From My Life With Polymer Science: Album 03, Otto Vogl Sep 2004

Pictures From My Life With Polymer Science: Album 03, Otto Vogl

Otto Vogl

No abstract provided.


Biomolecule-Directed Assembly Of Nanoscale Building Blocks Studied Via Lattice Monte Carlo Simulation, Ting Chen, Monica H. Lamm, Sharon C. Glotzer Aug 2004

Biomolecule-Directed Assembly Of Nanoscale Building Blocks Studied Via Lattice Monte Carlo Simulation, Ting Chen, Monica H. Lamm, Sharon C. Glotzer

Monica H. Lamm

The self-assembly of functionalized inorganic nanoscale building blocks (NBB) was investigated using recognitive biomolecule linkers. The NBBs and linkers were studied using bond fluctuation model and algorithm on a simple cubic lattices. The loops contained in the soluble material to avoid double counting when calculating the fraction of loops. The algorithm was used to calculate additional network properties when volume fractions above the percolation threshold was simulated.


Screening Of Mgo- And Ceo2-Based Catalysts For Carbon Dioxide Oxidative Coupling Of Methane To C2+ Hydrocarbon, Istadi, Nor Aishah Saidina Amin Aug 2004

Screening Of Mgo- And Ceo2-Based Catalysts For Carbon Dioxide Oxidative Coupling Of Methane To C2+ Hydrocarbon, Istadi, Nor Aishah Saidina Amin

Istadi

The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based solids with oxides from alkali (Li2O), alkaline earth (CaO), and transition metal groups (WO3 or MnO). The presence of the peroxide (O2_2 ) active sites on the Li2O2, revealed by Raman spectroscopy, may be the key factor in the enhanced performance of some of the Li2O/MgO catalysts. The high reducibility of the CeO2 catalyst, an important factor in the CO2-OCM catalyst activity, may be enhanced by the presence of …


Network Phases In Abc Triblock Copolymers, Thomas H. Epps Iii, Eric W. Cochran, Cordell M. Hardy, Travis S. Bailey, Ryan S. Waletzko, Frank S. Bates Aug 2004

Network Phases In Abc Triblock Copolymers, Thomas H. Epps Iii, Eric W. Cochran, Cordell M. Hardy, Travis S. Bailey, Ryan S. Waletzko, Frank S. Bates

Eric W. Cochran

Many naturally occurring and engineered products are influenced by network structures. Collagen networks provide a scaffold for living tissue, while swollen arrays of physically cross-linked polypeptides constitute gelatin, the familiar dessert and electrophoresis medium. Although the associated mesh sizes differ by several orders of magnitude, these examples share a common feature: three-dimensional connectivity that imparts mechanical rigidity. Intercalating additional interconnected components can yield broader functions, e.g., ionic or electrical conductivity, optical band gaps, and tailored heat and mass transfer.


Shear-Induced Network-To-Network Transition In A Block Copolymer Melt, Eric W. Cochran, Frank S. Bates Aug 2004

Shear-Induced Network-To-Network Transition In A Block Copolymer Melt, Eric W. Cochran, Frank S. Bates

Eric W. Cochran

The tricontinuous (10, 3)c shear-induced network-to-network transition in a block copolymer melt was analyzed using small-angle x-ray scattering. Investigations show that field-induced network-to-network phase transition was unprecedented in soft condensed matter. It was found that shear transforms were used for self-assembling the soft material into a single crystal (10, 3)d network. The results show the delicate nature of block copolymers phase behavior, where candidate morphologies were spaced closely together on the free energy surface.


Pictures From My Life With Polymer Science: Album 04, Otto Vogl Aug 2004

Pictures From My Life With Polymer Science: Album 04, Otto Vogl

Otto Vogl

No abstract provided.


Pictures From My Life With Polymer Science: Album 05, Otto Vogl Jul 2004

Pictures From My Life With Polymer Science: Album 05, Otto Vogl

Otto Vogl

No abstract provided.


Pictures From My Life With Polymer Science: Album 06, Otto Vogl Jun 2004

Pictures From My Life With Polymer Science: Album 06, Otto Vogl

Otto Vogl

No abstract provided.


Effect Of Hydrotreating Fcc Feedstock On Product Distribution, Rafael Maya-Yescas May 2004

Effect Of Hydrotreating Fcc Feedstock On Product Distribution, Rafael Maya-Yescas

Rafael Maya-Yescas

The demand of low-sulfur fuels has been increasing during the last 20 years due to environmental concerns about SOx emissions from processing plants and engines. Due to its high contribution to the gasoline pool, hydrotreating fluid catalytic cracking (FCC) feedstock offers several advantages, such as the increase of conversion and yields of gasoline and liquid-phase gas, meanwhile sulfur content in fuels is diminished. However, there are more important factors to be considered when hydrotreating FCC feedstock. In this work, two FCC feedstocks, typical and hydrotreated, were converted in a microactivity test (MAT) reactor, as described by ASTM D-3907-92, at different …


Translation Of Mat Kinetic Data To Model Industrial Catalytic Cracking Units, Rafael Maya-Yescas, Elizabeth León-Becerril, Daniel Salazar-Sotelo May 2004

Translation Of Mat Kinetic Data To Model Industrial Catalytic Cracking Units, Rafael Maya-Yescas, Elizabeth León-Becerril, Daniel Salazar-Sotelo

Rafael Maya-Yescas

Bench and laboratory scale reactors are required to infer kinetic data for catalytic cracking units. One of the most common methods is the microactivity test (MAT, ASTM D-3902-92), that emulates the catalyst-to-oil ratio using a fixed-bed reactor and a semi-batch accumulator of liquids. Translation of data obtained from MAT tests in order to infer kinetic parameter to model continuous industrial units is, consequently, difficult and uncertain. In this work, the extraction of kinetic data obtained in a MAT reactor is analyzed. Estimation of a kinetic rate equation to evaluate instantaneous conversion in MAT reactors is performed. The activation energy obtained …


Pictures From My Life With Polymer Science: Album 07, Otto Vogl May 2004

Pictures From My Life With Polymer Science: Album 07, Otto Vogl

Otto Vogl

No abstract provided.


Pictures From My Life With Polymer Science: Album 08, Otto Vogl Apr 2004

Pictures From My Life With Polymer Science: Album 08, Otto Vogl

Otto Vogl

No abstract provided.


Consequences Of Block Number On The Order-Disorder Transition And Viscoelastic Properties Of Linear (Ab)N Multiblock Copolymers, Lifeng Wu, Eric W. Cochran, Timothy P. Lodge, Frank S. Bates Apr 2004

Consequences Of Block Number On The Order-Disorder Transition And Viscoelastic Properties Of Linear (Ab)N Multiblock Copolymers, Lifeng Wu, Eric W. Cochran, Timothy P. Lodge, Frank S. Bates

Eric W. Cochran

The effect of block number on the order-disorder transition (ODT) and viscoelastic properties were studied for linear (AB) n multiblock copolymers. A series of symmetric poly(styrene-b-isoprene) n multiblocks ((SI) n, n = 1-10) were synthesized by anionic polymerization, and their order-disorder transition temperatures (T ODT) were located using dynamic mechanical spectroscopy. As n increases, T ODT approaches an asymptotic value, consistent with random phase approximation calculations. A systematic difference between the experimental and theoretical results is attributable to the effects of fluctuations, independent of the number of blocks. Addition of up to 20 vol % of a nonselective solvent depresses …


Pictures From My Life With Polymer Science: Album 09, Otto Vogl Mar 2004

Pictures From My Life With Polymer Science: Album 09, Otto Vogl

Otto Vogl

No abstract provided.


Pictures From My Life With Polymer Science: Album 10, Otto Vogl Feb 2004

Pictures From My Life With Polymer Science: Album 10, Otto Vogl

Otto Vogl

No abstract provided.


Hypothetical Thermodynamic Properties: The Boiling And Critical Temperatures Of Polyethylene And Polytetrafluoroethylene, James S. Chickos Jan 2004

Hypothetical Thermodynamic Properties: The Boiling And Critical Temperatures Of Polyethylene And Polytetrafluoroethylene, James S. Chickos

James Chickos

No abstract provided.


Efficient Wastewater Treatment Process For Brine Water, Carl Vavra, Adrian Bonilla-Petriciolet Jan 2004

Efficient Wastewater Treatment Process For Brine Water, Carl Vavra, Adrian Bonilla-Petriciolet

Adrian Bonilla-Petriciolet

The objective of this project is to develop a simple, economically feasible process for purifying salt water (brine) solutions. It involves choosing the best membrane for optimum performance, while reviewing durability, membrane service life, separation capabilities and costs. Scale-up data are collected to evaluate the commercial feasibility of this technology. The optimization of processing parameters (pressure, flow, temperature and concentration) is reviewed to maximize the performance of the membrane. Cleaning and sanitizing the membrane after use for storage and reuse will also need to be studied.


An Adsorbent Prepared For Fluoride Removal From Water, Rodolfo Trejo-Vázquez, Adrian Bonilla-Petriciolet Jan 2004

An Adsorbent Prepared For Fluoride Removal From Water, Rodolfo Trejo-Vázquez, Adrian Bonilla-Petriciolet

Adrian Bonilla-Petriciolet

In this paper, we report the preparation of an adsorbent for fluoride removal from drinking water. This adsorbent was prepared using a thermal treatment of pseudoboehmite agglomerates. Taguchi and Surface Response methodologies were used in order to standardize the adsorbent synthesis and to obtain the best fluoride removal rate of adsorbent. The fluoride removal rate of our adsorbent was higher than those obtained for a commercial alumina and bone charcoal. This adsorbent was also tested and compared using different experimental conditions with fluoride solutions and tap water.


Magnetophoresis Of Nonmagnetic, Submicrometer Particles In Magnetic Fluids, Seif-Eddeen K. Fateen Jan 2004

Magnetophoresis Of Nonmagnetic, Submicrometer Particles In Magnetic Fluids, Seif-Eddeen K. Fateen

Seif-Eddeen K Fateen

No abstract provided.


Effective Approach To Cyclic Steady State In The Catalytic Reverse-Flow Combustion Of Methane, Krzysztof Gosiewski Jan 2004

Effective Approach To Cyclic Steady State In The Catalytic Reverse-Flow Combustion Of Methane, Krzysztof Gosiewski

Krzysztof Gosiewski

Computer-based simulations of a reverse-flow reactor should be carried out till the attainment of the so-called cyclic steady state. Usuallythis state is achieved bythe method of direct dynamic simulations. In the paper of Unger et al. (Comput. Chem. Eng. 21 (1997) 5167.) special approaches, making use of various minimization algorithms based most often on Newton algorithms, are proposed. In the present paper one deals with a comparison and an appraisal of these methods, applied to the reverse-flow catalytic combustion of methane that occurs in coal-mine ventilation air.


Air Quality Regulation Policy In Portugal, João F. Gomes Jan 2004

Air Quality Regulation Policy In Portugal, João F. Gomes

João F Gomes

Ten years after the publication of first air quality laws in Portugal, and seven years after the publication of the respective emission limits, it seems appropriate to analyse the degree of law enforcement by the Portuguese manufacturing industry. Therefore, based on the emission measurements made regularly by ISQ, as the only officially accredited laboratory, a set of about 400 sources is analysed in terms of the compliance with the emission limits regarding total suspended particulate, sulphur dioxide, nitrogen oxides and VOCs. The compliance is evaluated through a non-dimensional parameter and plotted versus the emission flow rate to derive conclusions: it …


Dynamics Of Two-Phase Reactors With Approximate Kinetics, Francisco J. Valdes-Parada Jan 2004

Dynamics Of Two-Phase Reactors With Approximate Kinetics, Francisco J. Valdes-Parada

Francisco J. Valdes-Parada

Los sistemas de transporte y reacción en más de una fase han ido adquiriendo un interés creciente en la comunidad científica y tecnológica debido a que la gran mayoría de los procesos industriales se llevan a cabo en sistemas no homogéneos. De la misma forma, es notable el interés que se ha dado en las últimas décadas por los sistemas catalizados por enzimas.

Las enzimas como catalizadores son utilizadas actualmente en una gran variedad de procesos, como son la fabricación de etanol, insulina, ácido láctico, cerveza, vacunas, entre muchos otros; de hecho varias procesos clásicos han sido reemplazados por procesos …


Influence Of Boundary Slip On The Optimal Excitations In Thermocapillary Driven Spreading, Jm Davis, Sm Troian Jan 2004

Influence Of Boundary Slip On The Optimal Excitations In Thermocapillary Driven Spreading, Jm Davis, Sm Troian

Jeffrey M. Davis

Thin liquid films driven to spread on homogeneous surfaces by thermocapillarity can undergo frontal breakup and parallel rivulet formation with well-defined wavelength. Previous modal analyses have relieved the well-known divergence in stress that occurs at a moving contact line by matching the front region to a precursor film. Because the linearized disturbance operator is non-normal, a generalized, nonmodal analysis is required to probe film stability at all times. The effect of the contact line model on nonmodal stability has not been previously investigated. This work examines the influence of boundary slip on thermocapillary driven spreading using a transient stability analysis, …


Renewable Alkanes By Aqueous-Phase Reforming Of Biomass-Derived Oxygenates, George W. Huber, R. D. Cortright, J. A. Dumesic Jan 2004

Renewable Alkanes By Aqueous-Phase Reforming Of Biomass-Derived Oxygenates, George W. Huber, R. D. Cortright, J. A. Dumesic

George W. Huber

A clean stream of alkanes from renewable biomass resources is obtained through aqueous-phase reforming in a single reactor. Alkanes are produced from biomass-derived sorbitol through a bifunctional pathway (see scheme) that involves the dehydration of sorbitol on acid sites (SiO2/Al2O3) and hydrogenation of intermediates on a metal catalyst under a H2 atmosphere. Hydrogen is produced from sorbitol and water on the metal catalyst in the same reactor.


Effect Of Sn On The Reactivity Of Cu Surfaces, George W. Huber, A. Gokale, J. A. Dumesic, M. Mavrikakis Jan 2004

Effect Of Sn On The Reactivity Of Cu Surfaces, George W. Huber, A. Gokale, J. A. Dumesic, M. Mavrikakis

George W. Huber

Periodic, density functional theory (DFT-GGA) calculations, using PW91 (self-consistently) and RPBE functionals, have been employed to determine preferred binding sites, adsorbate structures, and binding energies for the adsorption of atomic (H, N, O, S, and C), molecular (NO and CO), and radical (OH) species on Cu(111) and CuSn(0001) alloy surfaces. Our results indicate the following order in the binding energies from the least to the most strongly bound:  NO < CO < H < OH < N < O < S < C for Cu-terminated CuSn(0001). On Cu(111), the corresponding relative order of adsorbates from the least strongly bound to the most strongly bound is CO < NO < H < OH < N < O < S < C. On the Sn-terminated CuSn(0001) surface, CO does not adsorb and the relative order of adsorbates from the least strongly bound to the most strongly bound is NO < H < OH < N < S < O < C. For all adsorbates, the binding on Cu-terminated CuSn(0001) is stronger than on Cu(111), resulting from a combination of electronic and strain effects caused by the addition of Sn to Cu. CO dissociation is endothermic on Cu-terminated CuSn(0001) and Cu(111) surfaces, while CO oxidation is exothermic on these surfaces. OH dissociation is endothermic on all three surfaces. On all surfaces studied, thermodynamics of NO decomposition are much more favorable than those of CO and OH dissociation on the corresponding surfaces. Our microcalorimetric studies of the interaction of NO with Cu/SiO2 and Cu6Sn5/SiO2 samples give initial heats of 270 (2.80 eV) and 130 (1.35 eV) kJ/mol, respectively. These values correspond to the decomposition of NO to give adsorbed oxygen plus gaseous N2 on Cu/SiO2 and adsorbed oxygen plus gaseous N2O on the Sn-terminated phase of Cu6Sn5/SiO2.