Showing papers by "Missouri University of Science and Technology published in 1999"

Development of a Functional Basis for Design

Abstract: Functional models represent a form independent blueprint of a product. As with any blueprint or schematic, a consistent language or coding system is required to ensure others can read it. This paper introduces such a design language, called a functional basis, where product function is characterized in a verb-object (function-flow) format. The set of functions and flows is intended to comprehensively describe the mechanical design space, Clear definitions are provided for each function and flow. The functional basis is compared to previous functional representations and is shown to subsume these attempts as well as offer a more consistent classification scheme. Applications to the areas of product architecture development, function structure generation, and design information archival and transmittal are discussed.

Examination of ionic liquids and their interaction with molecules, when used as stationary phases in gas chromatography.

Abstract: Stable room-temperature ionic liquids (RTILs) have been used as novel reaction solvents. They can solubilize complex polar molecules such as cyclodextrins and glycopeptides. Their wetting ability and viscosity allow them to be coated onto fused silica capillaries. Thus, 1-butyl-3-methylimidazolium hexafluorophosphate and the analogous chloride salt can be used as stationary phases for gas chromatography (GC). Using inverse GC, one can examine the nature of these ionic liquids via their interactions with a variety of compounds. The Rohrschneider-McReynolds constants were determined for both ionic liquids and a popular commercial polysiloxane stationary phase. Ionic liquid stationary phases seem to have a dual nature. They appear to act as a low-polarity stationary phase to nonpolar compounds. However, molecules with strong proton donor groups, in particular, are tenaciously retained. The nature of the anion can have a significant effect on both the solubilizing ability and the selectivity of ionic liquid s...

Mining multiple-level association rules in large databases

Abstract: A top-down progressive deepening method is developed for efficient mining of multiple-level association rules from large transaction databases based on the a priori principle. A group of variant algorithms is proposed based on the ways of sharing intermediate results, with the relative performance tested and analyzed. The enforcement of different interestingness measurements to find more interesting rules, and the relaxation of rule conditions for finding "level-crossing" association rules, are also investigated. The study shows that efficient algorithms can be developed from large databases for the discovery of interesting and strong multiple-level association rules.

Blunt-Body Wave Drag Reduction Using Focused Energy Deposition

Abstract: A parametric computational study of energy deposition upstream of generic two-dimensional and axisymmetric blunt bodies at Mach numbers of 6.5 and 10 is performed utilizing a full Navier-Stokes computational fluid dynamics code. The energy deposition modifies the upstream shock structure and results in large wave drag reduction and very high power effectiveness. Specifically, drag is reduced to values as low as 30% of baseline drag (no energy deposited into flow) and power effectiveness ratios (ratio of thrust power saved to power deposited into the flow) of up to 33 are obtained. The fluid dynamic and thermodynamic bases of the observed drag reduction are examined

Electrodeposited ceramic single crystals

Abstract: Single-crystal films are essential for devices because the intrinsic properties of the material, rather than its grain boundaries, can be exploited. Cubic bismuth oxide has the highest known oxide ion mobility, which makes it useful for fuel cells and sensors, but it is normally only stable from 729° to 825°C. The material has not been previously observed at room temperature. Single-crystal films of the high-temperature cubic polymorph of bismuth oxide were epitaxially electrodeposited from an aqueous solution onto single-crystal gold substrates. The 35.4 percent lattice mismatch was accommodated by forming coincidence lattices in which the bismuth oxide film was rotated in relation to the gold substrate. These results provide a method for producing other nonequilibrium phases that cannot be accessed by traditional thermal processing.

Separating microbes in the manner of molecules. 1. Capillary electrokinetic approaches.

Abstract: Selective, high-efficiency separations of intact bacteria may, in some cases, allow them to be identified and quantified in much the same way that molecules are done today. Two different capillary electrokinetic approaches were utilized. The first approach used a dissolved polymer-based CE separation that may be affected by size and shape considerations. Another approach uses capillary isoelectric focusing to separate bacteria by their surface charge or isoelectric point. Good peak shapes and extremely high efficiencies are observed (up to ∼1 600 000 theoretical plates/m). Careful sample preparation and separation runs are essential in order to obtain reproducible separations. Expansion of these types of rapid, efficient microbial separations could have profound effects on many branches of science and technology.

Functional Interdependence and Product Similarity Based on Customer Needs

Abstract: In this paper, related product functions are determined for a group of approximately 70 consumer products. Using customer need data, a new matrix approach is introduced to identify these relationships. Techniques are then created for determining product similarity. These techniques are clarified and validated through three case studies, including beverage brewers and material-removal products. The results of these case studies are argued to have significant impact on design-by-analogy procedures, bench- marking methods, mass customization strategies and modular design. The paper concludes with a discussion of applications and related procedures for product development.

Physical polymer surface modification methods and applications in food packaging polymers.

Abstract: Continued innovations in the polymer industry have made polymer surface modification methods a subject of intense research. The importance and necessity of surface modification of plastics are explained, and the advantages of physical surface treatments over the less-sophisticated chemical methods are outlined. Currently available physical surface modification methods for food packaging polymers are reviewed from the food packaging perspective. These physical surface modification methods include flame, corona discharge, UV, gamma-ray, electron beam, ion beam, plasma, and laser treatments. The principle of operation of each method is briefly described, and the advantages and disadvantages of each technique are cited. The extent to which each of these methods can produce the specific modifications desired is discussed. Furthermore, the effects of each treatment on barrier, mechanical, and adhesion properties of food packaging polymers are also examined. Finally, an overview of economic aspects of sophisticated surface modification techniques, including ion beam, plasma, and laser treatments, is presented.

On principal eigenvalues for quasilinear elliptic differential operators: an Orlicz-Sobolev space setting

Abstract: Abstract. ((without abstract.))

Effect of melting temperature and time on iron valence and crystallization of iron phosphate glasses

Abstract: The effect of melting temperature and time on iron valence, dissolution rate (DR) in deionized water, and crystallization of iron phosphate glasses was investigated using a 40Fe2O3–60P2O5, mol%, batch composition. The concentration of Fe2+ ions in these glasses increased from 17% to 57% as melting temperature increased from 1150°C to 1450°C, but remained nearly constant at about 20% for melting times longer than 1 h at 1200°C. Measurements by differential thermal analysis (DTA) combined with X-ray diffraction (XRD) and thermogravimetric analysis (TGA) showed that these glasses crystallized to Fe3(P2O7)2 and Fe4(P2O7)3 when heated in nitrogen between 600°C and 820°C, but with continued heating in air at 820°C the Fe3(P2O7)2 changed to Fe(PO4), which produced a weight gain in the sample associated with the oxidation of Fe2+ to Fe3+ ions. The DR (in deionized water) of these glasses was generally very low (∼10−9 g cm−2 min−1) and nearly independent of the relative concentration of Fe2+ or Fe3+ ions, but decreased with total iron content.

A Generalization-Based Approach to Clustering of Web Usage Sessions

Abstract: The clustering of Web usage sessions based on the access patterns is studied. Access patterns of Web users are extracted from Web server log files, and then organized into sessions which represent episodes of interaction between the Web users and the Web server. Using attribute-oriented induction, the sessions are then generalized according to a page hierarchy which organizes pages based on their contents. These generalized sessions are finally clustered using a hierarchical clustering method. Our experiments on a large real data set show that the approach is efficient and practical for Web mining applications.

Comparison of pure nicotine- and smokeless tobacco extract-induced toxicities and oxidative stress.

Abstract: The toxicities and oxidative stress-inducing actions of (-)-nicotine and smokeless tobacco extract (STE), containing equivalent amounts of nicotine, were studied. Toxicities were determined by colony formation assays using Chinese hamster ovary (CHO) cells. Results indicated that nicotine is less toxic than smokeless tobacco extract that contained the same amount of nicotine. The generation of reactive oxygen species, following treatment with smokeless tobacco extract and nicotine, was assessed by measurement of changes in glutathione (GSH) and malondialdehyde (MDA) levels. CHO cells (5 x 10(5) cells/5 ml media) were incubated with 4, 0.8, and 0.08 mg of nicotine and STE containing the same amounts of nicotine. All preparations of smokeless tobacco extract significantly decreased GSH levels and increased MDA generation. However, 0.08 mg of nicotine treatment did not result in a significant change in GSH level, and only 4 mg of nicotine were sufficient to increase MDA generation. Addition of free radical scavenging enzymes, superoxide dismutase (SOD) and catalase (CAT), and an intracellular GSH precursor, N-acetyl-L-cysteine (NAC), replenished the GSH levels in nicotine-treated cells. GSH levels in cells exposed to smokeless tobacco extract containing 4 and 0.8 mg nicotine remained significantly lower than the control with the addition of SOD and CAT. However, co-addition of NAC with smokeless tobacco extract preparations returned the GSH levels to the control level. Lactate dehydrogenase (LDH) activities were measured in the media to establish the membrane damage following exposure to smokeless tobacco extract and nicotine. Treatment of cells with 4 mg nicotine caused a significant increase in LDH activity, which was returned to control level in the presence of the antioxidant enzymes and NAC. Smokeless tobacco extract did not change the LDH activity. http://link.springer-ny. com/link/service/journals/00244/bibs/37n4p434.html

Distribution and Volatilization of Organic Compounds Following Uptake by Hybrid Poplar Trees

Abstract: Hybrid poplar trees were exposed to eleven organic compounds in hydroponic systems. The eleven contaminants were common pollutants with a wide range of physio-chemical properties such as the octanol-water partition coefficient, Henry's constant, vapor pressure, and molecular weight. Contaminants, 14C-labeled, were introduced into the root zone, and contaminant transport and fate were examined. Aqueous concentrations were monitored throughout each experiment as was vapor phase concentrations in the air stream passing over the leaves. At experiment conclusion, plant tissues were oxidized to determine 14C concentrations. The uptake, distribution, and volatilization of these contaminants varied greatly among the 11 contaminants in the study. Uptake and translocation of the contaminants ranged from < 0.3% (of the applied 14C-labeled compound) for 1,2,4-trichlorobenzene to 20% for benzene. Volatile compounds were volatilized from the leaves. Volatilization in the transpiration stream was related to the...

X-ray photoelectron and Mössbauer spectroscopic studies of iron phosphate glasses containing U, Cs and Bi

Abstract: The atomic structure of iron phosphate glasses and those containing common high level nuclear waste components such as UO2, Cs2O and Bi2O3 has been investigated using X-ray photoelectron spectroscopy (XPS) and Mossbauer spectroscopy. Oxygen 1s spectra indicate that only 16–26% of the oxygen ions are bridging oxygens (BOs). The addition of waste components such as UO2, Cs2O and Bi2O3 does not change the BO/(BO + NBO) ratio appreciably. Some structural similarities in the short range order was found between the glass and crystalline Fe3(P2O7)2 which crystallizes from the glass upon heat treatment. The Mossbauer hyperfine parameters, isomer shift and quadrupole splitting, showed that the environment around iron ions was independent of the composition. In general, the addition of waste elements does not alter the basic features of the parent glass. The measured isomer shifts and quadrupole splittings indicate that the Fe3+ and Fe2+ ions in these glasses are in octahedral or distorted octahedral coordination. The fraction of Fe2+ in the glass increases with the melting temperature. However, most physical properties of these glasses do not depend appreciably on the valence state of iron ions.

Deza graphs: A generalization of strongly regular graph

Abstract: We consider the following generalization of strongly regular graphs. A graph G is a Deza graph if it is regular and the number of common neighbors of two distinct vertices takes on one of two values (not necessarily depending on the adjacency of the two vertices). We introduce several ways to construct Deza graphs, and develop some basic theory. We also list all diameter two Deza graphs which are not strongly regular and have at most 13 vertices.

Hepatic tumor radioembolization in a rat model using radioactive rhenium (186Re/188Re) glass microspheres.

Abstract: Purpose: The aim of this study was to fully characterize newly developed radioactive rhenium glass microspheres in vivo by determining their biodistribution, stability, antitumor effect, and toxicity after hepatic arterial injection in a syngeneic rat hepatoma model. The dose response of the tumors to increasing amounts of radioactive 186 Re and 188 Re microspheres was also determined. Methods and Materials: Rhenium glass microspheres were made radioactive by neutron activation and then injected into the hepatic artery of Sprague–Dawley rats containing 1-week-old Novikoff hepatomas. The biodistribution of the radioactivity and tumor growth were determined 1 h and 14 days after injection. Results: Examination of the biodistribution indicated a time-dependent, up to 7-fold increase in Novikoff hepatoma uptake as compared to healthy liver tissue uptake. After 14 days, the average T:L ratio was 1.97. Tumor growth in the rats receiving radioactive microspheres was significantly lower than in the group receiving nonradioactive microspheres (142% vs. 4824%, p = 0.048). Immediately after injection, 0.065% of the injected radioactivity was measured in the thyroid; it decreased to background levels within 24 h. Conclusion: Radioactive rhenium microspheres are effective in diminishing tumor growth without altering hepatic enzyme levels. The microspheres are safe with respect to their radiation dose to healthy tissue and radiation release in vivo and can be directly imaged in the body with a gamma camera. Furthermore, rhenium microspheres have an advantage over pure beta-emitting microspheres in terms of preparation and neutron-activation time. In sum, this novel radiopharmaceutical may provide an innovative and cost-effective approach for the treatment of nonresectable liver cancer.

6Li, 7Li nuclear magnetic resonance investigation of lithium coordination in binary phosphate glasses

Abstract: {sup 6}Li and {sup 7}Li solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy has been used to investigate the local coordination environment of lithium in a series of xLi{sub 2}O {center_dot} (1-x)P{sub 2}O{sub 5} glasses, where 0.05 {le} x {le} 0.55. Both the {sup 6}Li and {sup 7}Li show chemical shift variations with changes in the Li{sub 2}O concentration, but the observed {sup 6}Li NMR chemical shifts closely approximate the true isotropic chemical shift and can provide a measure of the lithium bonding environment. The {sup 6}Li NMR results indicate that in this series of lithium phosphate glasses the Li atoms have an average coordination between four and five. The results for the metaphosphate glass agree with the coordination number and range of chemical shifts observed for crystalline LiPO{sub 3}. An increase in the {sup 6}Li NMR chemical shift with increasing Li{sub 2}O content was observed for the entire concentration range investigated, correlating with increased cross-linking of the phosphate tetrahedral network by O-Li-O bridges. The {sup 6}Li chemical shifts were also observed to vary monotonically through the anomalous glass transition temperature (T{sub g}) minimum. This continuous chemical shift variation shows that abrupt changes in the Li coordination environment do not occur as the Li{sub 2}O concentration is increased, and such abrupt changes can not be used to explain the T{sub g} minimum.

Membrane process for biological treatment of contaminated gas streams.

Abstract: A hollow fiber membrane bioreactor was investigated for control of air emissions of biodegradable volatile organic compounds (VOCs). In the membrane bioreactor, gases containing VOCs pass through the lumen of microporous hydrophobic hollow fiber membranes. Soluble compounds diffuse through the membrane pores and partition into a VOC degrading biofilm. The hollow fiber membranes serve as a support for the microbial population and provide a large surface area for VOC and oxygen mass transfer. Experiments were performed to investigate the effects of toluene loading rate, gas residence time, and liquid phase turbulence on toluene removal in a laboratory-scale membrane bioreactor. Initial acclimation of the microbial culture to toluene occurred over a period of nine days, after which a 70% removal efficiency was achieved at an inlet toluene concentration of 200 ppm and a gas residence time of 1.8 s (elimination capacity of 20 g m-3 min-1). At higher toluene loading rates, a maximum elimination capacity of 42 g m-3 min-1 was observed. In the absence of a biofilm (abiotic operation), mass transfer rates were found to increase with increasing liquid recirculation rates. Abiotic mass transfer coefficients could be estimated using a correlation of dimensionless parameters developed for heat transfer. Liquid phase recirculation rate had no effect on toluene removal when the biofilm was present, however. Three models of the reactor were created: a numeric model, a first-order flat sheet model, and a zero-order flat sheet model. Only the numeric model fit the data well, although removal predicted as a function of gas residence time disagreed slightly with that observed. A modification in the model to account for membrane phase resistance resulted in an underprediction of removal. Sensitivity analysis of the numeric model indicated that removal was a strong function of the liquid phase biomass density and biofilm diffusion coefficient, with diffusion rates below 10(-9) m2 s-1 resulting in decreased removal rates.

Ultrasonically initiated free radical‐catalyzed emulsion polymerization of methyl methacrylate (i)

Abstract: The emulsion polymerization of methyl methacrylate initiated by ultrasound has been studied at ambient temperature using sodium lauryl sulfate as the surfactant. The investigation includes the: (1) nature and source of the free radical for the initiation process; (2) effects of different types of cavitation; and (3) dependence of the polymerization rate, polymer particle number generated, and the polymer molecular weight on acoustic intensity, argon gas flow rate, surfactant concentration, and initial monomer concentration. It was found that the polymerization could be initiated by ultrasound in the emulsion systems containing methyl methacrylate, water, and sodium lauryl sulfate at ambient temperature in the absence of a conventional initiator. The source of the free radical for the initiation process was found to come from the degradation of the sodium lauryl sulfate, presumably in the aqueous phase. The weight average molecular weight of the poly(methyl methacrylate) obtained varied from 2,500,000 to 3,500,000 g mol−1, and the conversion for polymerization was up to 70%. Deviations from the Smith–Ewart kinetics were observed. The polymerization rate was found to be proportional to the acoustic intensity to the 0.98 power; to the argon gas flow rate to the 0.086 power; to the surfactant concentration to the 0.08 power, with the 0.035M–0.139M surfactant concentration range; and to the surfactant concentration to the 0.58 power, with the 0.139M–0.243M surfactant concentration range. The polymerization rate was found to increase with increasing initial monomer concentration up to a point where it became independent of initial monomer concentration. The polymer particle number generated per milliliter of water was found to be proportional to the acoustic intensity to the 1.23 power; to the argon gas flow rate to the 0.16 power; to the surfactant concentration to the 0.3 power, with the 0.035M–0.139M surfactant concentration range; and to the surfactant concentration to the 1.87 power, with the 0.139M–0.243M surfactant concentration range. The polymer weight average molecular weight was found to be proportional to the acoustic intensity to the 0.21 power, and to the argon gas flow rate to the 0.02 power. It was found to be inversely proportional to the surfactant concentration to the 0.12 and 0.34 power, with the 0.035M–0.139M and the 0.139M–0.243M surfactant concentration ranges, respectively. The polymer yield and polymerization rate were found to be much larger than those obtained from an ultrasonically initiated bulk polymerization method. The polymerization rates obtained at ambient temperature were found to be similar to or higher than those obtained from the conventional higher temperature thermal emulsion polymerization method. This investigation demonstrated the capability of ultrasound to both initiate and accelerate polymerization in the emulsion system, and to do this at a lower temperature that could offer substantial energy savings. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 797–825, 1999