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.
Results
Showing 1 to 20 of 138 for “"Polymorphs"”.
-
Growth and Toxicity of Amyloid β Polymorphs
Alzheimer's disease is a progressive neurodegenerative disorder and a leading cause of death worldwide. Despite extensive research, there is still no cure for the disease, possibly, due to insufficient understanding of the complex underlying causes. One of the hallmarks of Alzheimer’s is the …
-
Polymorphs, cyclodextrin inclusion complexes and salts of the bronchodilator tulobuterol
The aim of this thesis was to prepare polymorphs, cyclodextrin inclusion complexes and salts of tulobuterol, a drug with bronchodilating properties. Polymorphic drugs are of interest to the pharmaceutical industry because of their varied physical properties, whilst the increase in aqueous …
-
Diversity of compressional mechanisms among SiO2 polymorphs : case of coesite and cristobalite
… its simple chemical composition by numerous polymorphs. More than 30 stable or metastable phases of silica are known, most of which occur at ambient to moderate pressures (<9 GPa). Understanding polymorphism and densification mechanisms in silica is not only important from a geomaterial point …
-
Electrochemical properties of crystalline polymorphs of MnO2 in aluminum and zinc metal batteries
… liquid and aqueous electrolytes. Two crystalline polymorphs of MnO<sub>2</sub> are used: birnessite (δ-MnO<sub>2</sub>), a layered structure, and todorokite, a seldomly studied structure composed of large tunnels. For the Al batteries, two electrolyte were used: an ionic liquid containing …
-
EXPERIMENTAL AND COMPUTATIONAL ANALYSIS OF RELATIVE ENERGETIC STABILITIES OF CRYSTALLINE ANHYDROUS POLYMORPHS AND PSEUDOPOLYMORPHS
… or monotropic relationships between polymorphs, but also the precise transition temperature linking enantiotropic pairs. These combined experimental and computational methods were extended to analyzing the relative stabilities of not only pure solids, but also cocrystals. The …
-
Diversity of compressional mechanisms among SiO<sub>2</sub> polymorphs : case of coesite and cristobalite.
… its simple chemical composition by numerous polymorphs. More than 30 stable or metastable phases of silica are known, most of which occur at ambient to moderate pressures (<9 GPa). Understanding polymorphism and densification mechanisms in silica is not only important from a geomaterial point …
-
Responses to salinity of color polymorphs in two populations of the sea star, Pisaster achraceus
<p><em>Pisaster ochraceus</em> was analyzed to determine if varying salinities, animal color, or location affect the physiology of these sea stars. The three responses analyzed were aerobic respiration, ammonia excretion, and self-righting. The tested variables included two different color morphs …
-
A study of the crystal chemistry, electron density distributions, and hydrogen incorporation in the Al₂SiO₅ polymorphs
The Al₂SiO₅ polymorphs have been examined to provide new insights into their chemical bonding, their crystal chemistry, their equations of state, and the incorporation of water in the form of hydroxyl in their structures. The Al₂SiO₅ polymorphs provide a unique structural assemblage for a crystal …
-
Effects of polymorphs and of Fe-doping on the properties of engineered nano TiO2 for photocatalytic degradation of emerging pollutant
L'abstract è presente nell'allegato / the abstract is in the attachment
-
Analysis of drug polymorphism by diffuse reflectance visible spectroscopy- a novel approach
… of a novel approach to surface analysis of drug polymorphs, with the aim of extending the capabilities of this approach to perform real time analysis of polymorphic transformation during pharmaceutical product development. This was achieved here, using diffuse reflectance visible spectroscopy …
-
A study of the polymorphism of 4-methyl-2-nitroacetanilide and related compounds
The full crystal structures of three polymorphs of 4-methyl-2-nitroacetanilide (MNA) are described. The white form (MNA-l), is the most stable form. The least stable form is the amber farm (MNA-2). The yellow form (MNA-3) has been found to change in a topotactic manner into the white form. The …
-
New insights into Crystallization: From Thermodynamics to Polymorphism and Kinetics
… the impact of different electrolytes on glycine polymorphs. The obtained results of glycine polymorphs were well interpreted by the proposed mechanisms which were further supported by the experimental kinetic data of gamma-glycine crystal growth, highlighting that the valences rather than other …
-
Crystal structure prediction. A molecular modellling study of the solid state behaviour of small organic compounds.
… seek possible crystal packing arrangements (or polymorphs) a compound may adopt. Based on the chemical diagrams, this thesis investigates polymorphism of several small organic compounds. Plausible crystal packings of those compounds are generated, and their lattice energies are minimised using …
-
Polymorphism control and the formation of organic molecular nanocrystals
… solid is obtained making control of desired polymorphs difficult. The aim of this thesis is to: (1) Evaluate practical methods to produce organic molecular nano-crystals of the desired form; (2) determine the change in crystal solid properties with size; (3) develop a better fundamental …
-
UNDERSTANDING AND EVALUATING CRYSTAL POLYMORPHISM BY SECOND HARMONIC GENERATION MICROSCOPY
… both potentially stable and metastable crystal polymorphs are accessible during crystal formation. Conventional methods limit the detection of rare nucleation and rapid phase transitioning events due to their lack of selectivity and sensitivity. Inkjet printing of a solution confines the …
-
Evaluation of the Energetic Factors in Crystalline Pharmaceuticals Using Solid-state Density Functional Theory and Low-frequency Vibrational Spectroscopy
… pharmaceutical ingredients can adopt including polymorphs, hydrates, and cocrystals. In this work, low-frequency vibrational spectroscopies and rigorous quantum mechanical simulations are combined to provide a new technique for characterizing and investigating pharmaceutically relevant …
-
Vibrational spectroscopic techniques (Raman, FT-IR and FT-NIR spectroscopy) as a means for the solid-state structural analysis of pharmaceuticals
… transformation of salmeterol xinafoate polymorphs and two polymorphic forms of sulfathiazole has also been explored in this work leading to the development of a new method for the solid-state estimation of the transition temperature of entantiotropically related pharmaceutical polymorphs …
-
Computational framework for metastable materials discovery: integrating kinetics and accurate properties
… GeC, and SnC). A common family of tetrahedral polymorphs is identified, along with a high-pressure rocksalt phase. The tetrahedral polymorphs are long-lived, while the rocksalt transforms rapidly to the ground state. SnC is predicted to have exceptional electron mobility via accurate …
-
The synthesis of aluminium hydroxide and oxyhydroxide
… ( Al(OH)₃ ) and aluminium oxyhydroxide (AIOOH) polymorphs. The particular oxygen sublattice of the starting material is critical in determining which phases of beta alumina are formed. Boehmite and bayerite are known to yield pure β"-alumina. In this investigation, the differences in structure …
-
Synthesis and characterization of novel fluoride and oxide cathodes for rechargeable batteries
… cathode materials: the dirutile and rutile polymorphs of LiMnF4, and layered lithium-excess . . . Dirutile LiMnF4 was identified from high-throughput computation as a promising conversion cathode. The dirutile polymorph was synthesized through a new low temperature route, and the rutile …
Page 1 of 7