Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"chemical change"”.
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Some Studies on the Effect of Different Storage Temperatures Upon the Fat Constants and Acidity of Print Creamery Butter
… storage conditions butter deteriorates. Chemical changes occur, more or less pronounced, injuring the quality and thereby affecting the market value. One of the chief constituents which under goes noticeable chemical change is the fat, which is over 80% of the weight of ordinary creamery …
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Mineralogical investigation of coal mine roof shales in part of the southern Appalachian coal field
… failure may depend upon some mineralogical or chemical change caused by the increase in moisture on the rooms of the mine. In addition to the weathering process, some roof shales are notoriously susceptible to failure in those places where ground-water seepage is prevalent. The failures caused …
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Developing science concepts in secondary classrooms : an analysis of pedagogical interactions from a Vygotskian perspective
… first case involves teaching and learning about chemical change (focussing on the process of rusting) and the second about air pressure. In summary, the main aim of this thesis is to draw upon Vygotskian theory to develop ways of talking and thinking about language-based pedagogical strategies of …
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Antarctic Alteration of Meteorites
… been examined and characterised petrologically, chemically, and magnetically. Chemical analyses undertaken are major and trace elements measured in bulk and in spatially resolved analysis and bulk oxygen isotopes. Petrology has proven to control the weathering patterns and alteration state of the …
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In Actu Et In Silicio: Linear and Nonlinear Photophysical Characterization of a Novel Europium Complex, and Incorporating Computational Calculations in the Analysis of Novel Organic Compounds
… light; computer data can be stored by inducing a chemical change in a compound through irradiation with light. However, before any of these materials can be applied in such a way, their properties must first be analyzed for them to be deemed viable. The focus of this dissertation is the …
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Characterization of epitaxial semiconductor films by scanning tunneling microscopy at ambient pressure
… cleaved surfaces are prepared for imaging by wet chemical treatments. GaAs/AlGaAs and Si/SiGe multilayer structures are imaged with —1 nm resolution. The contrast in the STM images is believed to be topographic in origin, resulting either from selective etching during surface preparation or …
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Wireless chemical sensing schemes using environmentally sensitive hydrogels
<p>In situ sensing of chemical parameters such as pH, glucose, enzymes, and other analytes is of immense importance in health care and environmental monitoring. There has been considerable research in this area using hydrogels as a chemo-mechanical transducer. Hydrogels are water-swollen polymers …
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Interactions of halogens with amines
… that these complexes can undergo further chemical change during which the hydrogen iodide which is generated converts any unreacted amine to the corresponding hydroiodide salt. The latter is inert to oxidation by iodine under the conditions employed. It has been shown that this mode of …
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Metal/polymer interactions
… materials which exhibit exceptional thermal and chemical stabilities. Yet, there are a number of instances in which a polymeric material displaying low resistance and featuring similar physical, chemical, and thermal characteristics as polyimide would be desirable. Toward this goal, multilayered …
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Arctic Char Otolith Records of Recent Limnological Change in High Arctic Lakes
… have been undergoing significant physical and chemical changes in recent years due to climate warming and permafrost thaw. These changes have the potential to impact organisms residing in these environments such as Arctic Char (Salvelinus alpinus) which represent the top predatory fish in …
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POLY(N-ISOPROPYL ACRYLAMIDE)-COATED SURFACES: INVESTIGATION OF CYTOTOXICITY WITH MAMMALIAN CELLS AND THE MECHANISM OF CELL DETACHMENT
… polymers undergo a physical or chemical change when a stimulus is applied. One such material is poly(N-isopropyl acrylamide), (pNIPAM), which undergoes a conformation change in a physiologically relevant temperature range to release intact mammalian cell monolayers capable of …
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An Experimental Demonstration Of Converting Organic Liquids And Their Aqueous Solutions In A Film Boiling Reactor
… presents an experimental demonstration of a chemical reactor design based on film boiling using aqueous mixtures of ethylene glycol. Termed a Film Boiling Reactor (FIBOR), the reactor volume is established around a horizontal heater tube (Nickel Alloy-Inconel 600) that is immersed in the …
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Mathematical Modelling of a Tubular Reactor for Continuous Production of Synthetic Resins
… are estimated using standard procedures. The chemical kinetic data available are shown to be inadequate for use at the elevated temperatures employed in the reactor. A novel technique is therefore developed for evaluation of the high temperature urea-formaldehyde reaction data, The data are …
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Design and synthesis of mechanoresponsive materials and multivalent polymer-peptide conjugates
… that force drives productive and selective chemical change. In chapter two of this thesis, the effect of regiochemistry on the mechanochemical reactivity of a naphthopyran mechanophore is examined. A series of constitutional isomers was evaluated computationally, then synthesized and …
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Semi-Synthesis of the Transcription Factor SMAD2 Containing Caging Groups and Phosphoaminoacid Analogues
… modification (PTM) of a protein refers to any chemical change that occurs to the protein after its ribosomal synthesis. The seemingly endless number of PTMs can endow proteins with new functionalities that are not present in the unmodified proteins. In order to study the functions of PTMs on a …
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Organometallic Palladium Reagents for Polypeptide Bioconjugation and Macrocyclization
… difference in bioactivity accessed by this chemical change. In addition to potential application as a bicyclic linker, peptide cross-linking is achieved in high conversion using peptides containing a single cysteine. Furthermore, linear and cyclic peptide OACs are accessible through …
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Cheddar cheese : Its texture, chemical composition and rheological properties.
… between the textural attributes and the chemical and rheological parameters were investigated. No relationship between chemical composition and texture was identified, but correlations between the rheological parameters and the textural attributes were not uncommon. Multiple regression …
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Students' Mental Models of Chemical Reactions
… research on topics such as atomic structure and chemical bonding indicates that students’ mental models are often inconsistent with the scientific models, which may impede learning of advanced concepts. International research suggests that model-based teaching and learning in science education …
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Druck- und Temperaturbedingungen für sekundäre Schmelzbildungen im Rahmen alkalisilikatischer und karbonatitischer Intrusionen
… glass can be observed in all the treated samples.Chemical investigations were carried out by electron microprobe analysis. In comparison to the alkali feldspar and clinopyroxene of the starting material the feldspar and clinopyroxene of the treated samples don’t show any chemical change. The …
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La representación social que los estudiantes poseen acerca de las reacciones químicas y su incidencia en la construcción del concepto de cambio químico
En la presente tesis se acepta que la construcción del concepto estructurante cambio químico se ve atravesado por la interpretación que a nivel social se le otorga a este fenómeno. Por tal motivo se considera que la teoría de las representaciones sociales puede enriquecer el campo de conocimientos …
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