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Articles 12301 - 12330 of 14109

Full-Text Articles in Engineering

Network Model Investigation Of Gas Transport In Bidisperse Porous Adsorbents, John H. Petropoulos, John K. Petrou, Athanasios I. Liapis Jun 1991

Network Model Investigation Of Gas Transport In Bidisperse Porous Adsorbents, John H. Petropoulos, John K. Petrou, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A capillary network model consisting of a micropore network permeated by one of macropores of randomly varying size has been constructed. Although simplified (to keep computer space and time requirements low) in relation to a real bidisperse porous adsorbent or catalyst, it embodies the salient pore structural features likely to determine the gas-transport behavior of such porous solids. Suitable model calculations of Knudsen gas-phase and surface diffusion enabled us to (i) validate useful approximate methods for the more economical evaluation of network permeability and (ii) demonstrate certain important characteristic effects of nonrandom bidisperse pore structure on transport behavior and their …


Reactivities Of Some Aromatic Compounds At Supercritical Water Conditions, Chun-Cheng Tsao Jun 1991

Reactivities Of Some Aromatic Compounds At Supercritical Water Conditions, Chun-Cheng Tsao

Masters Theses

The goals of this study are the removal of nitrogen from the extraction products of coal by Supercritical Water and the development of an understanding of the reactions leading to this removal. Six model compounds with structures similar to the intermediates of the coal liquefaction processes were studied. Benzylamine generated toluene through hydrogen abstraction after the C-N bond rupture. To a lesser extent, the oxidation of the benzylic carbon took place leading to benzene formation. Both reaction pathways occurred with equal probability for benzylidenebenzylamine, producing comparable yields of benzene and toluene. Benzaldehyde generated benzene through the oxidation/decarboxylation sequence. Benzyl alcohol …


Mathematical Modeling Of Mass Transfer In Microvascular Wall And Interstitial Space, Daekyung Kim May 1991

Mathematical Modeling Of Mass Transfer In Microvascular Wall And Interstitial Space, Daekyung Kim

Dissertations

The dynamics of macromolecular transport across the microvascular wall and into the adjoining interstitial space was studied in the hamster cheek pouch using intravital fluorescence microscopy in combination with digital image processing. Fluorescein isothiocyanate-labe led dextrans (FITC-Dx) of 70,000 and 150,000 daltons were used as tracers. In each experiment, the time-dependent extravasation of FITC-Dx from a leakage site in a blood vessel was videotaped for about 2 hours. The macromolecular transport from individual microvessels was quantified by digital video-image processing. Histograms of the light intensity distributions for selected fields at various times were obtained and then converted to the interstitial …


Mathematical Modeling Of Chemical Vapor Deposition Processes And Its Application To Thin Film Technology, Norman W. Loney May 1991

Mathematical Modeling Of Chemical Vapor Deposition Processes And Its Application To Thin Film Technology, Norman W. Loney

Dissertations

A number of workers in the field of Chemical vapor deposition (CVD) have presented mathematical models in the literature. Some workers were able to produce analytical expressions for the interwafer concentration profile. These analytical expressions were based entirely on zero or first order chemical reaction rates. Until now, it appears that a chemical reaction rate expression that is not zero or first order directly, must be handled by a numerical scheme.

Presented herein is a mathematical model with an analytical interwafer concentration profile. This concentration profile is neither zero nor first order but shifts from zero to first order as …


Kinetic Studies On Pyrolytic And Oxidative Decomposition Of Chlorocarbons In A Tubular Flow Reactor, Yang Soo Won May 1991

Kinetic Studies On Pyrolytic And Oxidative Decomposition Of Chlorocarbons In A Tubular Flow Reactor, Yang Soo Won

Dissertations

Chloroform decay and product distributions were distinctly different in the absence and presence of added O2 and/or CH4. Increases in O2 concentration were observed to speed reagent loss, with a slower decay of chloroform observed for the CHCl3/CH4/Ar pyrolysis system. In CHCl3/CH4/O2, the major products were C2Cl4, CH2CCl2, C2HCl3, CO and CO2 over a wide temperature range. Minor products included CH2Cl2, CH3Cl, and C2H3Cl. When CH4 reactant was not present, …


Charcoal Catalyzed Ozone Decomposition Of Organic Pollutants In Water, Kin Ho May 1991

Charcoal Catalyzed Ozone Decomposition Of Organic Pollutants In Water, Kin Ho

Theses

A laboratory study has been performed on the wastewater treatment (destruction of organic species in water) using a novel process called Integrated Adsorption-Oxidation (IAO) where activated carbon is being utilized as a catalyst-adsorbent, and ozone as oxidant. The results of ozonation alone on the pollutants in water are also reported to provide a comparison with the adsorption-oxidation scheme in semi-batch reactions. All experiments were conducted at room temperature in a semi-batch reactor using five (water soluble) representative chemicals as pollutants: Aniline, Acetamide, Pyridine, N,N-dimethyl formamide and O-cresol. We also studied two volatile compounds: Trichloroethylene and Chloroform. Phenol was studied in …


Adiabatic Kinetic Studies Of The Cytidine/Acetic Anhydride Reaction By Utilizing Temperature Versus Time Data, Joseph John Shatynski May 1991

Adiabatic Kinetic Studies Of The Cytidine/Acetic Anhydride Reaction By Utilizing Temperature Versus Time Data, Joseph John Shatynski

Theses

It is possible to predict the kinetics of a reaction by using temperature versus time data under adiabatic conditions. This method was used for the cytidine/acetic anhydride reaction using a RC1 Mettler Reaction Calorimeter.

The authenticity of the experimental adiabatic system was verified by determining the kinetic parameters of a known reaction (hydrolysis of acetic anhydride) and comparing them to literature values.

For example, the average experimental activation energy, heat of reaction, and ln k0 values for the hydrolysis of acetic anhydride were 11.2 ±.5 kcal/gmole, -14.4 ± .2 kcal/gmole, and 12.74 ± .94 sec-1, respectfully, while …


Catalytic Oxidation Of Chlorinated Compounds Over Pdo/Al2o3 On A Monolith, Tai-Chiang Yu May 1991

Catalytic Oxidation Of Chlorinated Compounds Over Pdo/Al2o3 On A Monolith, Tai-Chiang Yu

Theses

The catalytic oxidation of trichloroethylene(TCE) and dichloromethane (DCM) was investigated over a catalyst containing 4% PdO on Al2O3 washcoat and on a cordierite monolith with 400 channels per in2. Reactivity and selectivity of the catalyst for the destruction of 200 ppm C2HCl3 and 500 ppm CH2Cl2 in air was evaluated over the temperature range 250 to 550 °C. This research was conducted in a tubular reactor system at space velocities of 4,000 to 24,000 v/v/hr. It was found that complete oxidation occurs at 500°C for DCM and 550°C for …


Model Calculational Approach To The Conformation Of Adsorbed Polypeptide Fragments, Timothy J. Mckeon Apr 1991

Model Calculational Approach To The Conformation Of Adsorbed Polypeptide Fragments, Timothy J. Mckeon

Opportunities for Undergraduate Research Experience Program (OURE)

The focus of the paper is to examine possible conformational changes of peptides when placed in the presence of a poly-synthetic material. A major concern in the pharmaceutical industry is the loss of potency of polypeptide drug products during processing, packaging and storage. An example of this is polymer syringes being used in place of glass ones. The effect is that some protien-derived products experience structural changes due to contact with the polymer. This is otherwise known as surface denaturation. In order to understand the energetics of interfacial polypeptide systems, a calculational approach was used via the program Alchemy. The …


Two-Phase Flow Measurement, Glenn Brenneke Apr 1991

Two-Phase Flow Measurement, Glenn Brenneke

Opportunities for Undergraduate Research Experience Program (OURE)

Liquid fuel engines have many applications in today's world. Diesel, spark-ignition, and gas turbine engines, and furnaces are just a few of the many applications of liquid fuel sprays. With the rising cost of fuel and need for energy conservation it is imperative that more efficient engines be developed. Analyzing liquid fuel spray characteristics non-intrusively could unlock the door to powerful highly efficient engines in the future.

The vaporization of fuel is mandatory in liquid fuel combustion. Vaporization and the fuel to air ratio are important characteristics of the spark-ignition engine. Compression ignition is controlled by the parameters of the …


Establishment Of A Phase/Doppler Particle Analyzer For Two-Phase Flow Experiments, J. L. Burget Apr 1991

Establishment Of A Phase/Doppler Particle Analyzer For Two-Phase Flow Experiments, J. L. Burget

Opportunities for Undergraduate Research Experience Program (OURE)

The accurate measurement of liquid spray drop size and velocity is important in a variety of applications. These applications include agricultural sprays, furnaces, spark ignition and compression ignition engines, gas turbines, and a variety of industrial processes. Because of the need to improve combustion efficiency and minimize soot and other harmful emissions, one of the most active areas of research is fuel spray combustion. Quantitative measurements of the vapor phase in fuel sprays is vital to the understanding of spray dynamics and the operation of combustion devices.

There are various measurement techniques available to measure vapor phase characteristics in a …


Vapor-Liquid Equilibrium Data For The Nh3-H2o System And Its Description With A Modified Cubic Equation Of State, Thomas M. Smolen, David B. Manley, Bruce E. Poling Apr 1991

Vapor-Liquid Equilibrium Data For The Nh3-H2o System And Its Description With A Modified Cubic Equation Of State, Thomas M. Smolen, David B. Manley, Bruce E. Poling

Chemical and Biochemical Engineering Faculty Research & Creative Works

New pressure-temperature-overall composition vapor-liquid equilibrium (VLE) data are reported for the ammonia-water system at five temperatures between 20 and 140 °C and up to 500 pela. These data have been converted to T-P-x data, and vapor-phase compositions have been calculated by means of a Rediich-Kwong equation of state modified to Include Peneloux's volume translation and a density-dependent mixing rule. In order to achieve agreement of calculated vapor-phase compositions with previous literature results, H was necessary to use different kij values In the vapor and liquid phases. © 1991, American Chemical Society. All rights reserved.


Thermal Compatibility Analysis Of The Passive Damping Treatment Proposed For The Space Shuttle Remote Manipulator System (Srms), Mahesh Chowdhary Apr 1991

Thermal Compatibility Analysis Of The Passive Damping Treatment Proposed For The Space Shuttle Remote Manipulator System (Srms), Mahesh Chowdhary

Mechanical & Aerospace Engineering Theses & Dissertations

The NASA Space Shuttle Remote Manipulator System (SRMS), due to its long reach and light weight construction has significant structural flexibility. Thus any routine use of SRMS often results in large amplitude oscillations with long settling time. A passive damping technique utilizing a constrained viscoelastic layer damping treatment has been proposed to augment the active control of these oscillations in order to enhance the system stability and the end effector positional accuracy. This thesis concerns with the thermal compatibility analysis of the proposed damping treatment. The necessity for thermal compatibility analysis arises from the fact that acceptable damping performance of …


Removal Of Chlorine From Chlorine-Nitrogen Mixture In A Film Of Liquid Water, Sarwan S. Sandhu Apr 1991

Removal Of Chlorine From Chlorine-Nitrogen Mixture In A Film Of Liquid Water, Sarwan S. Sandhu

Chemical and Materials Engineering Faculty Publications

In industry there are many examples of absorption of a gas with or without chemical reaction in the liquid phase. In physical absorption, a particular gaseous component is removed from a gas mixture due to its larger solubility in the liquid phase solvent. The removal of butane and pentane from a refinery gas mixture by a heavy oil in the liquid phase is an example of physical absorption. In absorption with chemical reaction, the gaseous component to be removed transfers across the gas-liquid interface due to a difference in the bulk chemical potentials or concentrations in the two phases. The …


Sedimentology Of The Bedford-Berea Sequence (Early Mississippian), Williams Field, Michigan, David Alan Balthazor Apr 1991

Sedimentology Of The Bedford-Berea Sequence (Early Mississippian), Williams Field, Michigan, David Alan Balthazor

Masters Theses

The Berea Sandstone has produced in excess of 1.6 million barrels of oil in the Williams field since discovery in 1980. Seven lithofacies are identified from conventional core in the Bedford-Berea sequence. These facies are interpreted as deltaic deposits comprising prodelta (Bedford Shale), delta front, destructive marine shale, abandoned distributary channel-fill, interdistributary bay-fill, transgressive marine sandstone, and marine shale (Sunbury Shale) facies. Passive channel-fill facies truncate reservoir sandstone bodies and compartmentalize the field NW-SE across the trend of the northwestplunging anticline.

The two reservoir facies in the Williams field are the delta front and transgressive marine sandstones. The sandstone framework …


Process For The Extracting Oxygen And Iron From Iron Oxide-Containing Ores, Surendra K. Kawatra, Timothy C. Eisele Mar 1991

Process For The Extracting Oxygen And Iron From Iron Oxide-Containing Ores, Surendra K. Kawatra, Timothy C. Eisele

Michigan Tech Patents

Oxygen and metallic iron are produced from an iron oxide-containing mineral, such as ilmenite, by extracting iron from the mineral with hydrochloric acid, separating solid residue from the resulting solution and drying same, electrolyzing the separated, iron chloride- containing solution to produce electrolytic iron and chlorine gas, combining the chlorine gas with water recovered from the drying and/or iron chloride-containing solution electrolysis steps of regenerate hydrochloric acid and recycling the hydrochloric acid to the extraction step. In an alternate embodiment, the chlorine gas is reacted with recovered water in the presence of a catalyst to produce hydrochloric acid which is …


Dendrite Spacings In Directionally Solidified Superalloy Pwa-1480, M. Vijayakumar, Surendra N. Tewari, James E. Lee, P. A. Curreri Feb 1991

Dendrite Spacings In Directionally Solidified Superalloy Pwa-1480, M. Vijayakumar, Surendra N. Tewari, James E. Lee, P. A. Curreri

Chemical & Biomedical Engineering Faculty Publications

Primary dendrite spacings and side-branch coarsening kinetics were examined in specimens of the single-crystal multicomponent commercial superalloy PWA-1480, which were directionally solidified in a positive thermal gradient. The experimentally observed dependence of primary dendrite spacings and side-branch coarsening kinetics on growth rate and thermal gradient were in agreement with the behavior predicted by analytical models developed for binary alloys.


A Combined Gel Entrapped And Membrane Attached Microbial Process For Biodegrading Organic Compounds, Fayaz Saifuddin Lakhwala Jan 1991

A Combined Gel Entrapped And Membrane Attached Microbial Process For Biodegrading Organic Compounds, Fayaz Saifuddin Lakhwala

Dissertations

A comparative study has been performed between two bioreactors treating phenol, one using calcium alginate entrapped microorganisms, and the other using microorganisms attached on the surface of a polymeric membrane. Laboratory experiments conducted in batch recirculation mode, as well as a continuous feed mode, showed that the calcium alginate bio-bead reactor is more efficient in treating high feed concentrations of phenol, while the membrane bioreactor is more effective in the lower concentration regime (less than 150 ppm). In batch recirculation mode, the reaction rates (expressed as mg phenol/hr*gm dry cells) in the membrane reactor are an order of magnitude higher …


Thermodynamics Of Strong Electrolyte Solutions : Prediction Of Osmotic Coefficients By Pair Correlation Function Method, One Kwon Rim Jan 1991

Thermodynamics Of Strong Electrolyte Solutions : Prediction Of Osmotic Coefficients By Pair Correlation Function Method, One Kwon Rim

Dissertations

Thermodynamic properties (osmotic coefficients) of strong electrolyte solutions have been studied by the method of statistical mechanics. First the charged soft sphere potential is developed based on the Pauling type model. Next the charged soft sphere potential is converted to the thermodynamically corresponding charged hard sphere potential by way of the perturbation method developed by Verlet and Weis. Simultaneously, the radial distribution function is developed by modification of the Exponential theory through introduction of the Stillinger-Lovett moment condition. The effective hard sphere diameter values calculated by the perturbation method are combined with the modified Exponential theory, and these quantities are …


A Study Of Biological Dentrification Of Munition Wastes, Sonia R. Venugopal Jan 1991

A Study Of Biological Dentrification Of Munition Wastes, Sonia R. Venugopal

Theses

Kinetics of denitrification were studied using a consortium from the Lawrence, Kansas municipal treatment plant. Experiments were conducted in the batch mode, under controlled oxygen and pH conditions. It was found that the Monod model can successfully perdict the experimental results of nitrate depletion. It was also found that when the pH is maintained at values between 7.0 and 8.5, nitrate can be treated in a batch mode without having any significant nitrite presence in the reactor. The experimentally determined kinetic parameters were used in preliminary calculations for sizing a sequencing batch reactor (SBR). An existing mathematical model for the …


Solid-Liquid Suspension In Agitated Vessels Provided With Multiple Impellers, Tong Li Jan 1991

Solid-Liquid Suspension In Agitated Vessels Provided With Multiple Impellers, Tong Li

Theses

A large number of references can be found in the literature on the effect of mixing parameters on the achievement of the minimum agitation speed to just suspend solid particles. In the vast majority of these studies the agitation system consisted of just one centrally mounted impeller. However, the determination of the minimum agitation speed to achieve the just suspended state when the additional impellers are used have received very little attention. It is the intent of this work to investigate the role of multiple impeller agitation system on the achievement of the complete particle suspension state. The effect of …


Coexistence Of Three Pure And Simple Competitors In Four Interconnected Bioreactors, Ming Wu Jan 1991

Coexistence Of Three Pure And Simple Competitors In Four Interconnected Bioreactors, Ming Wu

Theses

It is known that a homogeneous environment having invariant inputs cannot allow for steady state coexistence of any number of pure and simple competitors. However, it has been proven that two pure and simple competitors can coexist at a steady state in two interconnected chemostats, if the conditions are such that they allow a different species to grow faster in each one of the two vessels. It has been also shown that three pure and simple competitors cannot coexist in three interconnected chemostats, even if the conditions are such that a different population could grow faster (have the competitive advantage) …


Method For Treating Wood Against Fungal Attack, Peter E. Laks Jan 1991

Method For Treating Wood Against Fungal Attack, Peter E. Laks

Michigan Tech Patents

Complexes of sulfited tannin extract and a copper(II) ion effectively protect wood against fungal attack. The complex can be impregnated into wood in a single step treatment using a water/organic solvent system, or formed in situ by treating the wood with an aqueous solution containing the extract and subsequently treating the wood with an aqueous solution containing a copper (II) salt.


The Added Mass, Basset, And Viscous Drag Coefficients In Nondilute Bubbly Liquids Undergoing Small-Amplitude Oscillatory Motion, Ashok S. Sangani, D. Z. Zhang, A. Prosperetti Jan 1991

The Added Mass, Basset, And Viscous Drag Coefficients In Nondilute Bubbly Liquids Undergoing Small-Amplitude Oscillatory Motion, Ashok S. Sangani, D. Z. Zhang, A. Prosperetti

Biomedical and Chemical Engineering - All Scholarship

The motion of bubbles dispersed in a liquid when a small-amplitude oscillatory motion is imposed on the mixture is examined in the limit of small frequency and viscosity. Under these conditions, for bubbles with a stress-free surface, the motion can be described in terms of added mass and viscous force coefficients. For bubbles contaminated with surface-active impurities, the introduction of a further coeflicient to parametrize the Basset force is necessary. These coefficients are calculated numerically for random configurations of bubbles by solving the appropriate multibubble interaction problem exactly using a method of multipole expansion. Results obtained by averaging over several …


Unreachable Roots For Global Homotopy Continuation Methods, Soo Hyoung Choi, Neil L. Book Jan 1991

Unreachable Roots For Global Homotopy Continuation Methods, Soo Hyoung Choi, Neil L. Book

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.


A Mathematical Model Of A Sealed Nickel-Cadmium Battery, Deyuan Fan, Ralph E. White Jan 1991

A Mathematical Model Of A Sealed Nickel-Cadmium Battery, Deyuan Fan, Ralph E. White

Faculty Publications

A mathematical model for the charge and discharge of a sealed nickel-cadmium (Ni-Cd) battery is presented. The model is used to study the effect of transport properties of the electrolyte and kinetic parameters of the electrode reactions on the cell performance during the charge and discharge period. The model can also be used to demonstrate the changes of cell performance during cycling. Some comparisons between model predictions and experimental results indicate that the model predictions appear to fit the experimental data well. Sensitivity analyses illustrate that the sealed nickel-cadmium battery operates under activation control. It is also shown theoretically that …


Electrode Kinetics Of Oxygen Reduction In Lithium Carbonate Melt: Use Of Impedance Analysis And Cyclic Voltammetric Techniques To Determine The Effects Of Partial Pressure Of Oxygen, Bhasker B. Davé, Ralph E. White, Supramanian Srinivasan, A. John Appleby Jan 1991

Electrode Kinetics Of Oxygen Reduction In Lithium Carbonate Melt: Use Of Impedance Analysis And Cyclic Voltammetric Techniques To Determine The Effects Of Partial Pressure Of Oxygen, Bhasker B. Davé, Ralph E. White, Supramanian Srinivasan, A. John Appleby

Faculty Publications

The effects of the partial pressure of oxygen and temperature on the oxygen reduction on a submerged gold electrode in a lithium carbonate melt were investigated using cyclic voltammetry and impedance analysis. The values for the mass-transfer parameters, DCO, obtained from cyclic voltammetry and impedance analysis were in good agreement. The reaction orders for oxygen at 800°C were calculated to be about 0.3 for the exchange current density and 0.5 for the product DCO; these values are consistent with the mechanism proposed in the literature for oxygen reduction in Li2CO3 melt.


Modification Of Newman's Band(J) Subroutine To Multi-Region Systems Containing Interior Boundaries: Mband, D. Fan, Ralph E. White Jan 1991

Modification Of Newman's Band(J) Subroutine To Multi-Region Systems Containing Interior Boundaries: Mband, D. Fan, Ralph E. White

Faculty Publications

Newman's BAND(J) subroutine, which has been used widely to solve models of various electrochemical systems, is extended to solve a system of coupled, ordinary differential equations with interior boundary conditions. A set of coupled, linear ordinary differential equations is used to demonstrate the solution procedure. The results show that the extended technique has the same accuracy as that of using pentadiagonal BAND(J), but the execution speed is about five times faster than that of pentadiagonal BAND(J). Using sparse matrix solver Y12MAF to solve the same set of equations takes even longer time than pentadiagonal BAND(J).


Homogenous Functions In Thermodynamics, Stephen R. Addison Jan 1991

Homogenous Functions In Thermodynamics, Stephen R. Addison

Journal of the Arkansas Academy of Science

No abstract provided.


A Mathematical Model Of Electrochemical Reactions Coupled With Homogeneous Chemical Reactions, Ken-Ming Yen, Taewhan Yeu, Ralph E. White Jan 1991

A Mathematical Model Of Electrochemical Reactions Coupled With Homogeneous Chemical Reactions, Ken-Ming Yen, Taewhan Yeu, Ralph E. White

Faculty Publications

The zinc/bromine (Zn/Br2) flow battery has received considerable
attention in recent years [e.g., (2-4)]. Although it
is agreed that the solution chemistry is important in the
system, most of the work that has been done is concentrated
on the design variables. In this note the basic mass
transfer-solution and surface kinetics are studied to furnish
a better understanding of the system.