Physical Sciences and Mathematics Commons^™

University Of Missouri-Rolla Cloud Simulation Facility: Proto Ii Chamber, Daniel R. White, James L. Kassner, John C. Carstens, Donald E. Hagen, John L. Schmitt, Darryl J. Alofs, Alfred R. Hopkins, Max B. Trueblood, Max W. Alcorn, William L. Walker

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Graduate Center for Cloud Physics Research at UMR Has Developed a Cloud Simulation Facility to Study Phenomena Occurring in Terrestrial Clouds and Fogs. the Facility Consists of a Pair of Precision Cooled-Wall Expansion Chambers Along with Extensive Supporting Equipment. the Smaller of These Chambers, Described in This Article, is Fully Operational, and is Capable of Simulating a Broad Range of In-Cloud Thermodynamic Conditions. It is Currently Being Used to Study Water Drop Growth and Evaporation for Drops Nucleated (Activated) on Well-Characterized Aerosol Particles. Measurements Have Been Made Not Only for Continuous Expansions (Simulated Updraft) But Also for Cyclic Conditions, …

Dynamic Structure Of A Nonaqueous Lamellar Liquid Crystal: Comparison With The Aqueous Case, Stig Friberg, Anthony J.I. Ward, David W. Larsen

Chemistry Faculty Research & Creative Works

The lamellar phase of sodium dodecyl sulfate/decanol/glycerol has been compared to the analogous water-based system. Results of NMR studies of deuteriated alcohol and surfactant showed the bilayer to be more disordered in the nonaqueous case than in the phase made with water. The order profiles of the two systems, however, were of the same form, implying that the same essential packing requirements applied to each case. The overall increase in dynamic disorder observed in the glycerol system is a result of a transversely more disordered bilayer/solvent interface. © 1987, American Chemical Society. All rights reserved.

Polymerization In Nonaqueous Lyotropic Liquid Crystals With A Polymerizable Solvent, Stig Friberg, Chang Sup Wohn, Frances E. Lockwood

Chemistry Faculty Research & Creative Works

Lamellar liquid crystals of lecithin and 2-hydroxyethyl methacrylate (HEMA) were polymerized by using UV radiation. Optical microscopy, infrared spectroscopy, and small-angle X-ray diffraction were used to compare the structure prior to and after polymerization. The lamellar structure was retained after polymerization with increased interlayer spacing. © 1987, American Chemical Society. All rights reserved.

Calculation Of The Thermophysical Properties Of Ground State Sodium Atoms, Paul M. Holland, Louis Biolsi Jr.

Chemistry Faculty Research & Creative Works

Transport properties of dilute monatomic gases depend on the two body interaction potentials between the atoms. When two ground state sodium atoms interact, they can follow either of two potential energy curves corresponding to the Na₂ molecule in the X¹Σ⁺_g or the ³Σ⁺_u. Transport collision integrals and second virial coefficients of monatomic sodium have been calculated by accurately representing quantum mechanical potential energy curves with the Hulburt-Hirschfelder potential. The generally good agreement of calculated viscosities and second virial coefficients with the available experimental viscosities and with previously calculated virial coefficients provides …

Measurement Of The Condensation Coefficient Of Water In The Umr Cloud Simulation Chamber, Daniel R. White, James L. Kassner, John C. Carstens, Donald E. Hagen, John L. Schmitt, Darryl J. Alofs, A. R. Hopkins, Max B. Trueblood, M. W. Alcorn

Physics Faculty Research & Creative Works

Measurements of the condensation coefficient of water under conditions closely approximating those in natural atmospheric cloud have been made in the cooled-wall UMR cloud simulation chamber. Current measurements disclose a value of condensation coefficient near unity at the outset of the experiment, generally decreasing to lower values (~ .01) as the experiment progresses. The significance of the magnitude of condensation coefficient in atmospheric cloud is briefly discussed.

The Aminolysis Of N-Hydroxysuccinimide Esters. A Structure-Reactivity Study, Gary W. Cline, Samir B. Hanna

Chemistry Faculty Research & Creative Works

Twelve amines, which vary substantially in basicity and in steric environment around N, have been allowed to compete—in anhydrous dioxane solution—in the aminolysis of the N-hydroxysuccinimide esters of unsubstituted, p-OCH₃, p-N0₂, and 3,5-(N0₂)₂ benzoic acids. The amines, which encompass a basicity range of 6.5 pk units, display a 10000-fold variation in reactivity in their reaction with the p-N0₂ester. for the sterically unhindered amines, a Bronsted-type plot of log k_obsdvs. pK_a has a slope of ~0.7. The data fit a model (Satterthwait, A. C.; Jencks, W. P. J. Am. …

University Of Missouri--Rolla Cloud Simulation Facility: Proto Ii Chamber, Daniel R. White, James L. Kassner, John C. Carstens, Donald E. Hagen, John L. Schmitt, Darryl J. Alofs, Alfred Raymond Hopkins, Max B. Trueblood, Max W. Alcorn, William L. Walker

Physics Faculty Research & Creative Works

The Graduate Center for Cloud Physics Research at UMR has developed a cloud simulation facility to study phenomena occurring in terrestrial clouds and fogs. The facility consists of a pair of precision cooled-wall expansion chambers along with extensive supporting equipment. The smaller of these chambers, described in this article, is fully operational, and is capable of simulating a broad range of in-cloud thermodynamic conditions. It is currently being used to study water drop growth and evaporation for drops nucleated (activated) on well-characterized aerosol particles. Measurements have been made not only for continuous expansions (simulated updraft) but also for cyclic conditions, …

Fourier Transform Nmr Self-Diffusion Studies Of A Nonaqueous Microemulsion System, K. P. Das, A. Ceglie, B. Lindman, Stig Friberg

Chemistry Faculty Research & Creative Works

Self-diffusion coefficients of the components of the microemulsion system glycerol/hexanol/sodium dodecyl sulfate (SDS) were determined in the presence and absence of an oil, p-xylene, and the results were compared with those from corresponding aqueous systems (i.e., glycerol replaced by water). In the aqueous system, the water in the hexanol rich isotropic liquid showed a diffusion coefficient less than 10% of that of free water, while that of hexanol was roughly 80% of that of free hexanol; such restricted motion of the water is consistent with the presence of water as discrete droplets. Partial substitution of p-xylene for hexanol did not …

Surfactants And The Stratum Corneum Lipids, Stig E. Friberg, Lisa Goldsmith, Hamdan Suhaimi, Linda D. Rhein

Chemistry Faculty Research & Creative Works

A simplified mixture of model stratum corneum lipids was mixed with different surfactants to make a preliminary estimation of the influence of surfactants on the stratum corneum lipid structure. The results revealed differences between cationic and anionic surfactants and between anionic surfactants with different structures. © 1998.

Interaction Of Calcium With Hema/Maa Copolymers., Michael R. Van De Mark, N. D. Lian, M. Brandon, E. C. Eckstein

Chemistry Faculty Research & Creative Works

Polymeric materials based upon 2-hydroxyethyl methacrylate (HEMA) have been extensively used, especially in biomedical applications. Several reports have appeared in the literature during the past 20 years regarding the behavior of these materials upon exposure to body fluids. The results of these studies have ranged from good biocompatibility to calcification. The presence of methacrylic acid (MAA), in HEMA-based copolymers gives rise to a swelling transition at pH 7. The present study relates the swollen volume of HEMA/MAA gels to the concentrations of calcium salts at a pH where the MAA is ionized, as would occur for implanted gels. This swollen …

Lamellar Liquid Crystal And Other Phases In The System Sodium Dodecyl Sulfate, Hexylamine, Water, And Heptane, Jiafu Fang, Raymond L. Venable

Chemistry Faculty Research & Creative Works

Phase equilibria have been studied for the system composed of sodium dodecyl sulfate, hexylamine, heptane, and water. Greatest emphasis has been placed on the lamellar liquid crystal region and X-ray diffraction measurements. Equations are developed or modified to allow determination of the degree of penetration of water into the amphiphilic double layer as a function of water or amphiphile concentration. It is found that the interfacial area occupied by the polar or ionic head groups of amphiphiles increases with increasing water content. © 1987 Academic Press, Inc. All rights reserved.

Critical Phenomena In Nonaqueous Microemulsions, Stig Friberg, Yuh Chirn Liang

Chemistry Faculty Research & Creative Works

The pseudo ternary phase diagrams of the four-component system glycerol, sodium dodecyl sulfate, hexanol and decane with the weight ratio of hexanol to decane equal to 100/0, 90/10, 75/25, 50/50, and 25/75 were determined at 30°C. The systems gave only isotropic solutions and no liquid crystalline phases. The nonaqueous regions corresponding to the W/O microemulsion region in aqueous systems suggested critical behavior as demonstrated by the convergence of tie lines and by light scattering intensity which gave a pronounced maximum at the point of converging tie lines. This maximum was transferred to higher glycerol/hexanol ratios with added surfactant and to …

A Mössbauer Effect Study Of The Structural And Magnetic Properties Of Y₂(Fe₁₋ₓalₓ)₁₄B, Ying-Chang Yang, Dwayne E. Tharp, Gary J. Long, Oran Allan Pringle, William Joseph James

Chemistry Faculty Research & Creative Works

The crystallographic and magnetic properties of Y₂(Fe₁₋ₓAlₓ)₁₄B, where x equals 0.00, 0.02, 0.04, 0.06, and 0.08, have been investigated by Mössbauer spectroscopy and magnetic measurements at room temperature and 85 K. Magnetic anisotropy and magnetization changes with aluminum substitution indicate that, because of size, the aluminum preferentially occupies the j₂ site over the remaining five crystallographically nonequivalent iron sites. This preferential occupation has been confirmed by Mössbauer spectral studies, which indicate that the compositional variation of the hyperfine field for each site is related to the number of near-neighbor aluminum atoms for the site. This compositional variation is helpful in …

Measurement Of The Condensation Coefficient Of Water In The Umr Simulation Chamber, Daniel R. White, James L. Kassner, John C. Carstens, Donald E. Hagen, John L. Schmitt, Darryl J. Alofs, Alfred R. Hopkins, Max B. Trueblood, Max W. Alcorn, William L. Walker

Physics Faculty Research & Creative Works

The UMR Cloud Simulation Facility is described. The facility is designed to provide a controlled environment simulating the conditions of natural atmospheric processes. It consists of two cooled-wall expansion cloud chambers and peripheral instrumentation for generation and characterization of aerosols used for cloud formation studies. Results of initial studies of the growth of warm cloud droplets and inferred measurements of the condensation coefficient are described.

The Synthesis And Characterization Of Polycarbonates Based On 1,1'-Dihydroxyethyl-2,2'-Biimidazole, Judith J. Garces

Masters Theses

"The synthesis of polycarbonates formed by the reaction of 1,1'-dihydroxyethyl-2,2'-biimidazole and diphenyl or diethyl carbonates was investigated and the products formed were characterized. The molecular weights of the polymers were dependent on catalyst, ratio of starting materials, nature of carbonate (aromatic or aliphatic) and method of polymerization. Isolated polymers exhibit a linear structure. They have no well-defined melting points (melting pt. range of 280- 330⁰C) indicating low degree of crystallization, and undergo less than 9% decomposition below 200⁰C"--Abstract, page ii.

Foams From Aqueous Systems Of Polymerizable Surfactants, Stig Friberg, Jia Hwa Fang

Chemistry Faculty Research & Creative Works

Polymerization was made in aqueous foams stabilized by a combination of a polymerizable surfactant, sodium (ω)-acrylamidoundecanoate (NaAAU), and oleyl alcohol. The common two-phase foams stabilized by a monomolecular layer of surfactant were not sufficiently stable to allow polymerization in foamed form, nor were such foams obtained in the two-phase region of aqueous solution and the liquid crystalline phase of hexagonally packed cylinders. Sufficient foam stability was found first when the lamellar liquid crystal formed by the combination of oleyl alcohol, the NaAAU, and the water. These foams were polymerized and shown to retain the liquid crystalline structure after polymerization. © …

Conductivity Study Of The Microemulsion System Sodium Dodecyl Sulfate-Hexylamine-Heptane-Water, Jiafu Fang, Raymond L. Venable

Chemistry Faculty Research & Creative Works

Conductivity measurements on this system are interpreted in terms of the percolation and effective medium theories. From this interpretation, the ratio of hexylamine to sodium dodecyl sulfate in the microemulsion droplet surfaces can be deduced. Following that determination, it is possible to obtain approximate values for the radius of the water pools and the number and surface area of droplets per unit volume of the microemulsion system. © 1987.

Interobserver Reliability In The Interpretation Of Computed Tomographic Scans Of Stroke Patients, David Shinar, Cynthia R. Gross, Daniel B. Hier, Louis R. Caplan, Jay P. Mohr, Thomas R. Price, Philip A. Wolf, Carlos S. Kase, Irene G. Fishman, Joshua A. Barwick, Selma C. Kunitz

Chemistry Faculty Research & Creative Works

Interobserver Reliability in Interpretation of Computed Tomographic Images Was Studied by Six Senior Neurologists Who Independently Evaluated on a Standardized Stroke Data Bank Form the Brain Lesions of 17 Patients. the Results Analyzed with K Statistics Yielded Moderate to Substantial Agreement on Most Items of Interest Including the Stroke Pathology and Anatomy. in General, the Levels of Agreement Were as High as Previously Reported for the Diagnosis of the Mechanism of the Stroke, and Much Higher Than on Many Stroke History Items and Items of Neurologic Examination. Excellent Agreement Was Obtained for the Detection of Infarcts and Intracerebral Hemorrhage, and …

Microemulsions, Lyotropic Liquid Crystals, And Other Association Structures, Jiafu Fang

Doctoral Dissertations

"Phase diagrams have been determined showing the extent of the inverse micellar or microemulsion region for several ionic surfactants and some cosurfactants. Hexylamine has been found to be a very effective cosurfactant giving rise to very good water solubilizing capacity at extremely low surfactant concentrations and very low cosurfactant levels at rather high initial hydrocarbon levels.

A fairly extensive study of phase equilibria of the system composed of sodium dodecyl sulfate, hexylamine, heptane, and water has been carried out. The conductivity behavior of the inverse micellar or microemulsion phase of the system shows the percolation phenomenon. Low angle X-ray diffraction …

Amphiphile Association Structures, Yun Yang

Doctoral Dissertations

"The amphiphile association behavior of Aerosol OT (sodium di-w-ethylhexylsulfoccinate) and p-xylene in combination with mixtures of different ratios of glycerol/water systems was studied and compared to that in the corresponding water and glycerol systems. The presence of glycerol strongly destabilized the inverse hexagonal liquid crystal phase observed in the aqueous system. The glycerol showed more ability to penetrate into the amphiphile bilayer than water in the lamellar liquid crystal phase. The influences of water and glycerol on the organization of amphiphile in the lamellar liquid crystal phase are of the same order.

The gross diffusion coefficient of 1% 2,4-diamino-6-piperidinopyrimidine-3-oxide in …