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Agarwal, Vivek Ph.D. Advisor: Dr. Bose e-mail: viveka@egr.uri.edu |
NANOSTRUCTURED MATERIAL SYNTHESIS IN A SELF ASSEMBLED SURFACTANT MESOPHASE We have observed a novel transformation from a microemulsion to a gel phase by increasing the water content of a system consisting of bis(2-ethylhexyl) sodium sulfosuccinate(AOT), phosphatidycholine(lecithin), and 2,2,4 –trimethylpentane (isooctane). There is a six order of magnitude increase in viscosity and a rigid gel forms as the water content is increased above a specific threshold. Small angle neutron scattering experiments on this surfactant mesophase shows a pronounced peak with a characteristic d-spacing that is a function of system water content and temperature. The scattering patterns are consistent with models that describe the microstructure as columnar hexagonal at lower water contents and temperatures, and lamellar at higher water contents and temperatures. SANS is also able to capture the transition between these two structures. These structures are thermally reversible. Temperature quench experiments reveal that the time constant for the structure transformation are less than a few minutes. Direct imaging using Freeze Fracture is being used to capture the internal morphology.
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Feng, Yang Ph.D. Advisor: Dr. Lucia e-mail: fengy@egr.uri.edu |
FAST AND RELIABLE PROCESS SIMULATION IN SINGULAR REIONS Process simulation involves the
mathematical modeling of a process and subsequent determination
of one or more solutions to the corresponding model equations.
The presence of singular points can drastically alter the
performance of numerical methods for solving chemical process
model equations and, as a result, commonly used computational
tools such as Newton's method, trust region (or dogleg) strategies
and other equation-solving techniques can exhibit periodic/aperiodic
behavior, slow convergence, or divergence. Moreover, when norm
reduction is used, iterates can get trapped at singular points
that are local minima in the least-squares function.
This work is concerned with the convergence of Newton’s method and traditional and complex domain trust region methods in regions containing singular points that are either local minima and saddle points of the least squares function. It is shown that Newton’s method behaves periodically while traditional dogleg strategies exhibit slow convergence and terminate at singular points. Complex domain trust region methods, on the other hand, converge quickly and reliably to singular points using quadratic acceleration and subsequently to (nearby) solutions using eigendecomposition. Single variable nonlinear equations such as the Statistical Associating Fluid Theory (SAFT) equation of state are used to illustrate the challenges and resolutions of simulation in singular regions. |
Finger, Eric
Ph.D. Advisor: NA E-mail: NA |
SOLAR ENERGY OR WASTE HEAT Using solar energy a two-stage heat engine can be utilized for the generation of useful work for a wide range of applications. The development of a two-stage heat engine is the focus using environmentally friendly volatile working fluids with boiling points less than water. Water requires large heat loads for generating work as in fossil fuel powered electrical generation. Solar power generates heat at lower temperatures than fossil fuels therefore working fluids with suitable properties are desired to make the most efficient use of solar energy or waste heat for the conversion to useful work. Various working fluids will be studied. Energy generation from fuel cells will also be considered as a source of heat for the system, where the beneficial result will be improved efficiency of the fuel cell. |
Guo, Ruiguang Post Doctorate Advisor: Dr. Brown e-mail: guor@egr.uri.edu |
STUDIES OF CORROSION FATIGUE BEHAVIOR IN CABON FIBER COMPOSITE Carbon fiber composites have gained wide
use as lightweight, high strength substitutes in sporting goods
(racquets, golf clubs), airplane parts (bombers, jet fighters),
automobile parts (drive shafts), and in advanced rocket motor
systems (Space Shuttle, missiles). |
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THE PASSIVATION OF Al ALLOY WITH CHROMIUM COATINGS Corrosion protection of light metal
alloys such as those of AL often include the application
of chemical coating, such as chromium (Cr). Chromium appears
to be active coating providing a continuous source of an inhibitor
for repairing the film at defect sites. Concerns over the
environmental hazards presented by chromium demand the replacement
of the chromium coatings by more environmentally benign materials.
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M.S. Advisor: Dr. GreenField E-mail: srivasy@egr.uri.edu |
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Yang, Shaohua PhD Advisor: Dr. Knickle |
Study on Aluminum-Air Battery
and Its Application to Electrical Vehicles
Objectives of this study is to improve
of the efficiency of the aluminum airbatteries through electrolyte, anode,
cathode study, and demonstrate its ability for vehicles applications by
evaluating aluminum as an energy storage and estimating the performance and
cost of the vehicles powered by this system.Aluminum air batteries have the
potential to be used to produce electricity to power cars and other vehicles.
These batteries might be an important on aninterim basis as the United State
passes through the transition from gasoline cars to hydrogen fuel cells
cars for the battery could generate enough energy and power for driving
ranges and acceleration similar to gasoline powered cars. The major problem
in using this system is the low coulombic efficiency of aluminum in strong
alkaline media resulting from its high corrosion(hydrogen evolution reaction)
rate and high level of polarization during discharge. Using high grade (99.999%
or 5N) of aluminum doped with other minorelements such as Mg, Mn, Ga, In,
Sn and Zinc etc can reduce corrosion and but increases the material cost.
At present we will focus on study of methods in the improvement of the efficiency
of this system, such as use of lower grade of aluminum or aluminum alloys
(thus low costs), more effective electrolyte additives and cathodes with
low polarization.To demonstrate its ability of this system for vehicle applications,
this system must provide vehicles with range, acceleration capability of
internal combustion engine (ICE) vehicles on an economically sound base,
thus the analysis and estimation of the performance and cost of the fuel
(aluminumanode), the batteries and the vehicles powered by this system will
be also an important part of our study.
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You, Tao PhD. Advisor: Dr. Greogory e-mail: tyou8777@postoffice.uri.edu |
MICROORGANISM FOR THE PRODUCTION OF HYDROGEN AND BIOPOLYMER BY PHOTOBIOREACTOR Molecular hydrogen is a non-polltuing
fuel that may play a role in the future energy economy.
Photobiological H2 production processes use whole cells
of photosynthetic bacteria, cyanobacteria or green algae for
solar H2 production. Anoxygenic photosynthetic bacteria particularly
the purple nonsulfur bacteria, are very efficient organism for
H2 production. Hydrogen production could be combined with organic
waste treatment.
Desirable properties like durability and resistance to degradation have made plastic materials an integral part of contemporary life. The standard plastics formulation used today include polyolefins, polyesters and polyurethanes, all of which are petroleum based and non-degradable. In addition hazardous chemicals are needed for their production as well as their disposal. The environment problem means that there is an increased for biopolymer. The most useful of all the microbiolly derived biodegradable plastics are the poly-hydroxy-butyrates (PHB). PHB stays flexible from sub-zero temperature to 130, and completely breaks down into water and carbon dioxide in a few months. It is degraded by a wide variety of microorganism flouring in the soil. My effort has been aimed to find a microorganism capable of producing the hydrogen and biopolymer by the bioreactor, to find the optimal conditions and the best photobioreactor for production. Four kinds of bacterium: anaerobic bacteria, photosynthetic bacteria and green alge are used for the hydrogen production. Most of research works are related to two kinds of microorganism. Rhodobacter Sphaeroodes RV, Synechococcus sp. (Cyanobacteria). The efficiency of hydrogen production depends on environmental parameters, such as light, ambient aerobicity, medium flow rate and type of photobioreactor etc. A thermophilic cyanobacteria, Synechoccous sp. accumulates PHB at more than 20% of cell dry at under nitrogen – starved conditions. The meophilic Synechocous PCC 7942 is transformed with the genes encoding PHB – synthetic enzymes from Alcaligenes eutrophus. Combinations of various and nitrogen substration also is used for PHB accumulation and H2 evolution by photosynthetic bacteria Rhodobacter sphaeroides strain RV. The cells evolved hydrogen on lactate, pyruvate-glutamate media. An increased in pH caused a decrease in H2 production and increase in PHB accumulation on lacate under nitrogen-deprived condition |
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Department of Chemical Engineering
University of Rhode Island
