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Fluid FirstMaurer, Jaclyn, Houtkooper, Linda 07 1900 (has links)
2 pp. / This publication provides simple tips for keeping active children hydrated when playing youth sports.
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Neural network analysis of the effects of contaminants on properties of cement pastesStegemann, Julia Anna January 2001 (has links)
No description available.
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Crystallographic studies of the sequence selective interactions of ligands within the minor groove of AT-rich DNASimpson, Ian John January 1999 (has links)
No description available.
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Spectroscopic studies of anomalous hydrodynamic behaviour in complex fluidsEdington, David W. N. January 2002 (has links)
Brillouin spectroscopy probes the thermally generated pressure fluctuations (sound waves) which propagate in a material. The resulting information on sound velocity and absorption provides a fast and efficient method of monitoring high frequency (GHz) dynamics in the system being studied. In certain cases, structural information may also be inferred from changes in the Brillouin spectrum as a function of temperature, pressure or composition (in the case of multi-component systems). The aim of the work presented in this thesis was to integrate Brillouin spectroscopy into current soft condensed matter research projects at Edinburgh, namely (i) hydration in methanol-water mixtures and (ii) the behaviour of hard-sphere colloidal dispersions. A Brillouin spectrometer based on a Fabry-Perot interferometer was developed and tested, resulting in a high-resolution instrument operating at variable scattering vector (exchanged momentum), temperature and pressure. The technical aspects of this work were carried out in collaboration with a colleague. Data analysis routines were designed and implemented, enabling calibrated Brillouin spectra to be produced automatically from raw experimental data. Excellent agreement with results on several materials studied in the literature confirmed the accuracy and sensitivity of the spectrometer. The molecular details of hydration in methanol-water mixtures are of great interest due to the prototypical amphiphilic nature of the methanol molecule. The effect of deep cooling on the Brillouin spectrum across a wide range of methanol concentrations was studied in detail, resulting in the first observation of an anomalous increase in sound velocity and maximum in sound absorption at intermediate compositions. A similar effect was then found at higher temperature in aqueous tertiary butanol, and was identified in a brief survey of several other aqueous solutions. High pressure Brillouin spectra indicate that this anomalous behaviour may also be present in pure water. It is suggested that these novel effects may be due to the presence of a relatively unperturbed water structure in the aqueous solutions studied, even at quite high solute concentration. Preliminary results from a neutron diffraction experiment performed on a 40% by mass methanol-water mixture were consistent with this hypothesis. Brillouin spectroscopy was also used to study the propagation of high frequency sound in monodisperse colloidal suspensions of sub-micron hard spheres. A second longitudinal sound mode was observed for scattering vectors of magnitude greater than pi/d where d is the diameter of the spheres. These results are the first reproduction and extension of the pioneering work in the field, which identified the additional mode with a surface acoustic excitation, propagating between adjacent spheres via an evanescent wave in the solvent. The new results show that the second mode is extinguished at a particular scattering vector - an effect not reported previously. It is suggested that this extinction is due to the minimum in the form factor for elastic scattering from a single sphere.
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Cement microstructure evolution during the hydration process for nuclear waste immobilisationWen, Yanli January 2018 (has links)
Cement has been selected for wastes immobilization as a simple, low temperature and low cost process for decades. The mechanical and immobilization properties of cement are mainly decided by cement hydration process, especially in the first 24 hours. Previous methods for studying the cement hydration are those include isothermal calorimetry, continuous monitoring of chemical shrinkage, in situ quantitative X-ray diffraction, nuclear magnetic resonance spectroscopy (NMR), quasi-elastic neutron scattering (QENS) and small angle neutron scattering (SANS). Few available in-situ imaging methods were successfully used for net rate study of cement hydration. In this Ph.D. research, innovative imaging techniques such as X-ray computed tomography (XCT) combined with 2D SEM-BSD analysis were combined to study the microstructure and phase change of cement or cement & SrCl2 mixture during hydration. Digital Volume Correlation (DVC) and Digital Image Correlation (DIC) were applied to study the chemical volume shrinkageand drying shrinkage of cement samples during hydration. The effects of SrCl2 simulating the radioactive nuclide from nuclear waste on cement hydration were studied by XRD and ICP-AES techniques. These studies verified that the hydration net rate could be characterised by XCT imaging techniques and the volume shrinkage of cement or cement& SrCl2 mixture during hydration could be characterised by the DVC and DIC techniques.
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Probing Hydrophobic Hydration Of Non-ionic Chains And Micellar Assemblies Using Molecular Dynamics SimulationsJanuary 2015 (has links)
Water-mediated interactions between non-polar moieties play a crucial role in driving self-assembly processes such as surfactant micellization, protein folding, and many other diverse phenomena. Among a variety of forces contributing to the self assembly, hydrophobic interactions play a dominant role. Historically, thermodynamic models describing hydrophobic effects have invariably relied on macroscopic thermodynamic properties to infer this molecular behavior. Experimental studies help to probe the spatial correlations between model hydrophobic solutes and to measure their waters of hydration in order to examine structural perturbations in the surrounding water induced by the solute, or to measure directly the attractive forces between hydrophobic surfaces. Further, molecular simulations can be used to derive entropic and enthalpic contributions to the free energy of hydrophobic hydration in terms of water structure surrounding simple, model hydrophobic solutes, such as methane. Based on the results for simple solutes, these methods can now be extended to investigate the hydrophobic hydration of more complex molecular solutes of arbitrary size and shape such as micelles. Atomistic simulations of chemical systems provide a new perspective towards testing the theories behind the ubiquitous phenomenon of hydrophobic effect, and probe the underlying thermodynamic signatures. In this context, my research work delves into the water-mediated interactions leading to the hydrophobic hydration of short chain alkanes, volumetric properties of unfolded polypeptides and self-assembly mechanism in polymer-surfactant systems. The first part of my research involves re-optimization of existing force field interaction parameters for the CHn alkane sites (n=0 to 4) to accurately reproduce the experimental hydration free energies of linear and branched chain alkanes over a range of temperatures. This Hydrophobic Hydration-Alkane (HH-Alkane) model accounts for polarization effects in the alkane hydration and can be extended to polypeptides in water. Subsequent discussions will focus on the results from extensive molecular simulations of tri- and tetrapeptides to quantify the accuracy of the simulation model in capturing the volumetric properties of unfolded polypeptides. Group additivity correlation was used to calculate the partial molar volumes of the neutral sidechains of amino acids, glycine backbone unit and both zwitterionic and N-acetyl/amide terminal units. The simulation results will be compared to the experimental results to validate these observations. In addition, the research explores the self-assembly and aggregation mechanism in anionic sodium dodecyl sulfate (SDS) surfactant- non-ionic Polyethylene Oxide (PEO) and Poly vinyl pyrrolidone (PVP) polymer systems. Potential of mean force calculations at multiple temperatures show an increasing trend in hydrophobic attractions within the polymer-micelle system. Also, these simulations provide interesting insights into the experimentally observed phenomena between the polymers and the micelles starting from pre-formed structure as well as random configurations. / 1 / Lalitanand N. Surampudi
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Thermal behavior of food materials during high pressure processingRamaswamy, Raghupathy. January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 131-142).
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The application of size- resolved hygroscopicity measurements to understand the physical and chemical properties of ambient aerosolSantarpia, Joshua Lee 29 August 2005 (has links)
During the summer of 2002, a modified tandem differential mobility analyzer
(TDMA) was used to examine the size-resolved hydration state of the ambient aerosol in
Southeast Texas. Although there were slight variations in the measured properties over
the course of the study, the deliquescent particles observed were almost always present as metastable aqueous solutions. A relative humidity (RH) scanning TDMA system was
used to measure the deliquescence/crystallization properties of ambient aerosol
populations in the same region. During August, sampling was conducted at a rural site in
College Station, and in September at an urban site near the Houston ship channel.
Measurements from both sites indicate cyclical changes in the composition of the soluble fraction of the aerosol, which are not strongly linked to the local aerosol source. The observations show that as temperature increases and RH decreases, the hysteresis loop
describing the RH-dependence of aerosol hygroscopic growth collapses. It is proposed
that this collapse is due to a decrease in the ammonium to sulfate ratio in the aerosol
particles, which coincides with increasing temperature and decreasing RH. This cyclical
change in aerosol acidity may influence secondary organic aerosol (SOA) production and
may exaggerate the impact of the aerosol on human health. The compositional changes
also result in a daily cycle in crystallization RH that is in phase with that of the ambient
RH, which reduces the probability that hygroscopic particles will crystallize in the
afternoon when the ambient RH is a minimum. During June and July of 2004 airborne
measurements of size-resolved aerosol hygroscopic properties were made near Monterey,
California. These were used to examine the change in soluble mass after the aerosol had
been processed by cloud. The calculated change in soluble mass after cloud-processing
ranged from 0.66 g m-3 to 1.40 g m-3. Model calculations showed these values to be
within the theoretical bounds for the aerosols measured. Mass light-scattering efficiencies
were calculated from both an averaged aerosol size distribution and from distributions
modified to reflect the effects of cloud. These calculations show that the increase in mass
light-scattering efficiency should be between 6% and 14%.
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Probing immobilised lipase mobility by solid state proton NMRKennedy, David January 2000 (has links)
No description available.
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Water and ion balance during pre-ovulatory hydration in teleostean occytesWatanabe, Wade O January 1982 (has links)
Bibliography: leaves 219-229. / Microfiche. / xiv, 229 leaves, bound ill. 29 cm
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