超臨界水中的溶解和化學反應受到一系列因素的影響，如溶解能，熵以及溶液密度等，是決定化學平衡的基本熱力學量，同時這些又受到溫度和壓強的控制。爲了解釋這些因素的影響，有必要把量子化學的靜態優化與分子動力學模擬相結合和比較。通過量子化學可以得到0K下的優化結構，而分子動力學模擬可以提高實際時間的勢能面。本論文的研究，主要圍繞在氣態下甲醛分子HCHO和甲酸分子HCOOH跟不同數目水分子H2O結合的水合簇結構，以及在常溫水溶液和超臨界水溶液中，甲醛HCHO和甲酸HCOOH的溶解結構和溫度所帶來的熱效應，最後研究甲酸HCOOH在水催化下的離解反應機理。 / 使用化學計算軟件Gaussian03和密度泛函理論方法，用6-311++G(d,p)基組來計算和研究氣態下甲醛分子和甲酸分子的水簇合物。通過不同數目的水分子所得到的最穩定簇合物的結構和能量，來研究甲醛分子HCHO，甲酸根離子HCOO⁻以及甲酸分子HCOOH與水分子相互結合時的氫鍵作用力強弱和簇合物的穩定性。同時，也考慮了甲酸酸解后的水簇合物結構，通過與沒有酸解的水簇合物的比較，為進一步瞭解水溶解中甲酸的酸解離情況提供寶貴的信息。 / 使用基於贗勢和平面波基組，以及密度泛函理論的從頭計算分子動力學軟件VASP，來模擬和研究甲醛分子HCHO和甲酸分子在水溶液中的溶解情況。根據對半徑關聯函數PRDF的統計結果，可以觀察出溶質的溶解結構，以及溶劑分子之間，或者溶質與溶劑分子之間的氫鍵作用。通過水合數目可以看出氫鍵作用力隨著溫度的提升而減弱。水溶液的溫度在臨界點之上時，其結果證實了甲酸的酸解反應受到嚴重的抑制，與常溫水的結果相反。 / 使用從頭計算分子動力學軟件CPMD中基於Car-Parrinello分子動力學方法的Metadynamics方法對甲酸的反應機理進行系統的研究，包含脫水反應和脫氫反應。解離反應分別包含不同數目的分子，通過對比來研究反應中水分子所起的潛在的催化作用。除此之外，通過300K和700K這兩種不同溫度下的結果對比，來解釋超臨界水溶解中甲酸快速解離的原因。自由能曲面和自由能壘揭示了在不同環境下甲酸的主要解離途徑。 / Solvation and chemical reactions in supercritical water are affected by a number of factors. Solvation energy, entropy, and densities are the basic thermodynamic quantities that determine the chemical equilibriums, which can be controlled by temperature and pressure. To account for these factors, static optimization leading to zero-temperature structures should be combined and compared with molecular dynamics simulation in real time. In my thesis, the solvation structures are studied in gas phase and aqueous phase, to understand the properties of solvent water and the thermal effect on the reactions. / The hydrated clusters of formaldehyde and formic acid in gas phase are explored computationally by density functional theory (DFT) with a basis set 6-311++G(d,p). Investigation on the structures and energies of hydrated HCHO, HCOO⁻ and HCOOH solvated by a number of water molecules is important for understanding the hydrogen bond interactions as the number of water molecules increases. Comparisons between non-dissociated and dissociated clusters of hydrated formic acid provide valuable information on the acidic dissociation of formic acid in aqueous solution. / The solvations of formaldehyde and formic acid in aqueous solution are simulated by density functional theory based ab initio molecular dynamics (AIMD) method with pseudopotentials and a plane wave basis set using Vienna Ab-initio Simulation Package (VASP). The pair radial distribution function is obtained to elucidate the solvation structure and the hydrogen bond interaction among solvent molecules, and between solute and solvent. The hydration number indicates the weakening of the hydrogen bond with increasing temperature. The results at the temperatures above the critical point of water show that the acid dissociation of formic acid is greatly depressed which is different from the results in ambient water. / The mechanisms for the dissociations of formic acid in the gas phase and in aqueous solution are studied by Car-Parrinello (CP)-based metadynamics (MTD) method, implemented in the Car-Parrinello Molecular Dynamics (CPMD) program. The two main dissociations channels of dehydration and dehydrogenation, including zero, one, two and bulk water molecules, respectively, are simulated with a biased external potential to examine the potential catalytic role of water. In addition, the thermal effects at two different temperatures are included to account for the rapid dissociation of formic acid in supercritical water. The free energy surfaces are reconstructed and the barriers are calculated to show the main dissociation pathway of formic acid in different environments. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chen, Qiubo. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 185-194). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / TITLE PAGE --- p.i / ABSTRCACT (ENGLISH) --- p.ii / (CHINESE) --- p.v / AKNOWLEDGEMENTS --- p.vii / TABLE OF CONTENTS --- p.viii / LIST OF FIGURES --- p.xiv / LIST OF TABLES --- p.xxiv / Chapter Chapter ONE --- Background / Chapter 1.1 --- Introduction of green chemistry --- p.1 / Chapter 1.1.1 --- Green chemistry --- p.1 / Chapter 1.1.2 --- Supercritical fluid (SCF) and supercritical water (SCW) --- p.2 / Chapter 1.2 --- Formaldehyde and formic acid in supercritical water --- p.8 / Chapter 1.2.1 --- Formaldehyde --- p.8 / Chapter 1.2.2 --- Formic acid --- p.12 / Chapter 1.3 --- Scope of this thesis --- p.17 / Chapter Chapter TWO --- Theories and Calculation Methods / Chapter 2.1 --- General background --- p.19 / Chapter 2.1.1 --- Schrödinger equation --- p.19 / Chapter 2.1.2 --- Born-Oppenheimer approximation --- p.20 / Chapter 2.2 --- Hartree-Fock (HF) approximation and post-Hartree-Fock (post-HF) approximation --- p.22 / Chapter 2.3 --- Density functional theory (DFT) --- p.28 / Chapter 2.3.1 --- Kohn-Sham (KS) scheme --- p.29 / Chapter 2.3.2 --- Local density approximation (LDA) --- p.31 / Chapter 2.3.3 --- Generalized gradient approximation (GGA) --- p.33 / Chapter 2.3.4 --- Hybrid functionals --- p.34 / Chapter 2.4 --- Ab initio molecular dynamics (AIMD) --- p.35 / Chapter 2.4.1 --- Molecular dynamics --- p.35 / Chapter 2.4.2 --- Ab initio molecular dynamics --- p.36 / Chapter 2.4.3 --- Plane waves --- p.42 / Chapter 2.4.4 --- Pseudopotentials (PP) --- p.44 / Chapter 2.4.5 --- Periodic boundary condition (PBC) --- p.48 / Chapter 2.5 --- Metadynamics (MTD) method --- p.48 / Chapter 2.5.1 --- The Algorithm --- p.49 / Chapter 2.5.2 --- Lagrangian metadynamics and the choice of V(t,s) --- p.52 / Chapter 2.5.3 --- The choice of CVs --- p.53 / Chapter Chapter THREE --- Structures of the Hydrated Clusters of Formaldehyde and Formic Acid / Chapter 3.1 --- Introduction --- p.55 / Chapter 3.2 --- Computational details --- p.56 / Chapter 3.3 --- Results and discussions --- p.58 / Chapter 3.3.1 --- Studies of HCHO(H₂O)[subscript n] clusters, n = 0~4 --- p.58 / Chapter 3.3.1.1 --- The structures of HCHO(H₂O)[subscript n] clusters, n = 0~4 --- p.58 / Chapter 3.3.1.2 --- The energies of HCHO(H₂O)[subscript n] clusters, n = 0~4 --- p.63 / Chapter 3.3.2 --- Studies of HCHO⁻(H₂O)[subscript n] clusters, n = 0~6 --- p.65 / Chapter 3.3.2.1 --- The structures of HCHO⁻(H₂O)[subscript n] clusters, n = 0~4 --- p.66 / Chapter 3.3.2.2 --- The energies of HCHO⁻(H₂O)[subscript n] clusters, n = 0~4 --- p.71 / Chapter 3.3.2.3 --- Studies of HCOO⁻(H2O)[subscript n] clusters, n = 5 and 6 --- p.73 / Chapter 3.3.3 --- Studies of HCOOH⁻(H2O)[subscript n] and HCOO⁻(H₃O)⁺(H₂O)[subscript n-1] clusters --- p.76 / Chapter 3.3.3.1 --- Results of cis-HCOOH(H₂O)[subscript n] clusters and trans-HCOOH(H₂O)[subscript n] clusters, n = 0 ~ 4 --- p.76 / Chapter 3.3.3.2 --- Results of trans-HCOOH(H₂O)[subscript n] clusters, n > 4 --- p.82 / Chapter 3.3.3.3 --- Comparisons of non-dissociated trans-HCOOH(H₂O)[subscript n] clusters with dissociated ion pair HCOO⁻(H₃O)⁺(H₂O)[subscript n-1] clusters --- p.84 / Chapter 3.4 --- Summary --- p.87 / Chapter CHAPTER FOUR --- Ab initio Molecular Dynamics Studies on the Solvations of Formaldehyde HCHO and Formic Acid HCOOH in Water Solution at Different Temperatures / Chapter 4.1 --- Introduction --- p.90 / Chapter 4.2 --- Computational details --- p.93 / Chapter 4.3 --- Results and discussions --- p.94 / Chapter 4.3.1 --- The solvation of water solution --- p.94 / Chapter 4.3.1.1 --- The solvation of pure water solution at T = 300 K, 600 K, 700 K and 2000 K --- p.95 / Chapter 4.3.1.2 --- The solvation of proton H⁺ in water solution at T = 300 K and 700 K --- p.101 / Chapter 4.3.2 --- The solvation of formaldehyde HCHO in water solution at T = 300 K, 500 K, 700 K and 900 K --- p.104 / Chapter 4.3.3 --- The solvation of formate ion HCOO⁻ in water solution at T = 300 K, 500 K, 700 K and 900 K --- p.109 / Chapter 4.3.4 --- The solvation of formic acid HCOOH in water solution at T = 300 K, 500 K, 700 K and 900 K --- p.117 / Chapter 4.4 --- Summary --- p.125 / Chapter CHAPTER FIVE --- The Reactions of Formic Acid HCOOH: Insights from Car-Parrinello Based Metadynamics (MTD) Method / Chapter 5.1 --- Introduction --- p.128 / Chapter 5.2 --- Computational details --- p.130 / Chapter 5.3 --- Results and Discussions --- p.132 / Chapter 5.3.1 --- The intrinsic rotation of a single formic acid molecule HCOOH in gas phase at T = 300 K and T = 700 K --- p.132 / Chapter 5.3.2 --- The dehydration of formic acid in gas phase at T = 300 K and T = 700 K --- p.140 / Chapter 5.3.2.1 --- The dehydration of a single formic acid molecule trans-HCOOH --- p.140 / Chapter 5.3.2.2 --- The dehydration of formic acid molecule trans-HCOOH with one water molecule --- p.147 / Chapter 5.3.2.3 --- The dehydration of formic acid molecule trans-HCOOH with two water molecules --- p.152 / Chapter 5.3.3 --- The dehydrogenation of formic acid in gas phase at T = 300 K and T = 700 K --- p.158 / Chapter 5.3.3.1 --- The dehydrogenation of a single formic acid molecule cis-HCOOH --- p.158 / Chapter 5.3.3.2 --- The dehydrogenation of formic acid molecule cis-HCOOH with one water molecule --- p.163 / Chapter 5.3.3.3 --- The dehydrogenation of formic acid molecule cis-HCOOH with two water molecule --- p.167 / Chapter 5.3.4 --- The dissociations of formic acid in water solution at T = 300 K and T = 700 K --- p.171 / Chapter 5.3.4.1 --- The acid dissociation of formic acid in water solution --- p.173 / Chapter 5.3.4.2 --- The dehydration of formic acid in water solution --- p.175 / Chapter 5.3.4.3 --- The dehydrogenation of formic acid in water solution --- p.178 / Chapter 5.4 --- Summary --- p.181 / References --- p.185

Herein we describe a straight-forward and reproducible method for the preparation of homogeneous, multicomponent cocrystals and supramolecular solid solutions. We prepared these multicomponent materials based on small organic molecules that employ a two-point supramolecular hydrogen bond synthon. We report the creation and characterization of two, three, four, five, and seven component crystals containing a variety of 2-aminopyridines and monosubstituted benzoic acids. These systems exhibit the ability to accommodate multiple components in varying proportions while coordinating into an identical packing structure. The flexibility of the system to incorporate multiple components also gives rise to gradual modulation of physical properties.

The present work is a continuation of the ideas developed in previous projects during my Masters studies that explored the relation between pattern, form and space. Starting from the pattern multiplication for space construction the present project proposes textiles as an assortment of flexible expressions. The purpose of the project is to explore aesthetic and functional potential of textiles for out door temporary structures. This is to create a pattern interface which filters sunlight through a textile surface to offer instant sheltering solutions for out door activities. The project combines research and analyses of outdoor temporary structures and scope of textile in the area. The research is interpreted into a concept of a portable space for relaxation. The design process shapes this concept of relaxation into a sun shelter.

Genrich Saulovich Altshuller (☼1926 - †1998) pesquisou milhares de patentes com o objetivo de sistematizar o processo de solução de problemas. De sua pesquisa nasceu a TRIZ, Teoria para a Resolução de Problemas do Inventor. Ela é composta de várias ferramentas e métodos que foram validadas na Rússia na década de 1980. Na década seguinte a TRIZ migrou para o ocidente, principalmente para Alemanha e Estados Unidos, por meio de emigrantes russos que fugiam das dificuldades econômicas em seu país. A TRIZ é pouco conhecida no Brasil e não existe quase nenhuma literatura sobre ela em português. No capítulo 1 é apresentada a motivação para este trabalho. No capítulo 2 são apresentados os conceitos da teoria. No capítulo 3 suas ferramentas. Os capítulos 2 e 3 formam um compêndio da metodologia de Altshuller. No capítulo 4 é proposta uma maneira de utilizar a TRIZ e, em seguida, no capítulo 5, por meio de estudos de casos, avalia-se a metodologia para aplicação na indústria automotiva. No capítulo 6 o autor apresenta uma proposta para o treinamento e disseminação da metodologia dentro de uma empresa. Por fim, no capítulo 7, conclui-se que é possível auferir um diferencial positivo frente à concorrência com o uso da TRIZ, apesar da dificuldade em aprendê-la. / Genrich Saulovich Altshuller (☼1926 - †1998) search thousands of patents aimed on systematize the problem solving process, using creativity. This research leads to a set of tolls and methods to name TRIZ (Russian acronym) or TIPS (English acronym). These tools and methods were extensively validated by Altshuller and his students and collaborator during 80’s decade. Ten years late it was spread through the west by "triznik" migration. TRIZ isn’t well known in Brazil and there are a few literatures, almost any, in Portuguese. First chapter presents the motivation for this piece of work. Chapter 2 introduces TRIZ concepts and chapter 3 displays its tools. In the chapter 4 a way to use the Altshuller methodology is proposed. Chapter 5 shows three cases using TRIZ in an Automotive Industry. In the chapter 6, the author suggests a training format. Finally, chapter 7 concludes TRIZ is a good way to make profits, in spite of it’s learn difficulty.

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In this study we provide a new proof of C¹,α boundary regularity for finite perimeter sets with flat boundary which are local minimizers of a variational mean curvature formula. Our proof is provided for curvature term H∈LΩ. The proof is a generalization of Cafarelli and C#243;rdoba's method, and combines techniques from geometric measure theory and the theory of viscosity solutions which have been developed in the last 50 years. We rely on the delicate interplay between the global nature of sets which are variational minimizers of a given functional, and the pointwise local nature of comparison surfaces which satisfy certain PDE. As a heuristic, in our proof we can consider the curvature as an error term which is estimated and controlled at each point of the calculation.

Over the last 100 Years, the cyanidation process has been the most popular method for recovering gold from its ores. Despite this, there are still efforts to improve the efficiency of the process, particularly as ores become more difficult to treat. Many investigators have studied the cyanidation process, although a large proportion of these studies have obtained contradictory results. This thesis presents a kinetic and electrochemical study of the leaching of gold in cyanide solutions, and emphasis is placed on rationalising the conflicting results which have been published in the past.The leaching rate of gold was measured using a rotating electrochemical quartz crystal microbalance, an instrument which allows the simultaneous measurement of electrochemical data and mass changes at the solid-solution interface in real time. A proportion of this project was devoted to the on-going design of this instrument, and a number of modifications are discussed in detail. Initially, the leaching of gold in cyanide solutions was investigated under conditions of high purity. Under these conditions, it was found that the gold surface is blocked by a passive film, presumably AuCN. The presence of such a film results in the reaction being chemically controlled, and under typical cyanidation conditions (4 mM cyanide, pH 10.0), the rate of dissolution is very low. These kinetic results were supported by complimentary electrochemical studies, which showed that gold is passive in the potential region where cyanidation occurs.The second part of this thesis presents a study of the effect of system purity on the leaching of gold in cyanide solutions. Solution phase purity was investigated by adding controlled amounts of lead or silver to the leach solutions. It was found that in the presence of low concentrations of lead, the dissolution of gold in 20 mM cyanide solutions was oxygen ++ / diffusion controlled (as compared to chemical control for gold in the absence of lead). However, high concentrations of lead were found to be detrimental to the leaching process. It is believed that the role of lead is to modify the surface by cementation, hence reducing the effect of the passive film. Silver was also found to be effective at reducing passivation, and the role of silver believed to be similar to that of lead. It was found that unlike lead, high concentrations of silver are not detrimental to the dissolution of gold in cyanide solutions.Solid phase purity was also found to be important in the leaching of gold, and it was found that the leaching of a gold sample which contains 1 % silver is diffusion controlled. This finding is important from an industrial viewpoint, as most native gold contains some silver. Consequently, attempts were made to rationalise the leaching of gold/silver with current plant practice. Discussion on the effect of cyanide and oxygen concentrations, temperature and lead addition is presented.

This thesis is submitted as a portfolio of peer-reviewed publications. / For many geochemical systems, reaction kinetics determines the system's current status and evolution. It might also be the key to unraveling their thermal history. In metal sulfide systems, kinetic studies have been carried out on four sets of solid-state transitions/transformations in Fe-Ni-S and Ni-S systems. In this work, a new kinetic model, the Refined Avrami method, has been developed to account for reactions involving changes in reaction mechanisms. Nonstoichiometric compounds are commonly present in these reactions. The exsolution of pentladite from the monosulfide solid solution (mss) is an important reaction in the formation of nickel ores. For near equimolar mss compositions, the reaction rate is rapid even in the low temperature ranges. For bulk composition Fe₀.₇₇ Ni₀.₁₉ S, the experimental results show the reaction rates ( mss → pentlandite ) vary from 1.6x10⁻⁵ to 5.0x10⁻⁷ s⁻¹ at 200 °C and from 9.4x10⁻⁵ to 4.1x10⁻⁷ s⁻¹ at 300 °C. The activation energy, E [subscript a], varies during the course of reaction from 49.6 kJ.mol⁻¹ at the beginning of reaction (nucleation mechanism is dominant) to 20.7 kJ.mol⁻¹ at the end (crystal growth mechanism is dominant). Monosulfide solid solution (mss) is a common intermediate phase observed during the oxidation of nickel ores, such as violarite and pentlandite. The investigation of mss oxidation is of benefit in understanding the thermal behavior of economically important metal sulfides during smelting. The oxidation products of mss vary in our samples depending on their compositions. Apart from the common oxidation products hematite and Ni₁ ₇ S₁₈, Fe₂ (SO₄) ₃ was observed during the oxidation of Fe₇ . ₉ S₈ and pentlandite for Fe₆ . ₁ ₅Ni₁ . ₅₄ S₈ . The activation energy was determined using a model-free method. The oxidation of Fe₆.₄ Ni₁.₆ S₈ exhibited a higher E [subscript a] than Fe₆ . ₁ ₅Ni₁ . ₅₄ S₈ over the course of the reaction. The E [subscript a] increases with reaction extent (y) from 67.1 to 103.3 kJ.mol⁻¹ for mss composition Fe₆ . ₁ ₅Ni₁ . ₅₄ S₈ and from 76.1 to 195.0 kJ.mol⁻¹ for Fe₆.₄ Ni₁.₆ S₈ . The kinetic study of the α - Ni₁₋ ₓ S → β - NiS transition shows that initial compositions of α - Ni₁₋ ₓ S plays an important role in the kinetics of the transition. The activation energy ( E [subscript a] ) for this α - to β - phase transition is 16.0 ( ± 0.5 ) kJ.mol⁻¹ for NiS in the temperature range 70 to 150 °C, and 13.0 (± 0.5) kJ.mol⁻¹ in the temperature range 250 to 350 °C. For Ni₀. ₉₇ S, however, E [subscript a] deceases from 73.0 ( ± 0.5 ) to 17.0 ( ± 0.5 ) kJ.mol⁻¹ over the course of the reaction in the temperature range 300 to 320 °C. The relationship between E [subscript a] and extent of transition (y) for the initial bulk Ni₀. ₉₇ S was derived using the Refined Avrami method. For Ni deficient compositions, α - Ni₁₋ₓ S, the transformation to β-NiS is accompanied by the exsolution of either a progressively more Ni deficient α-Ni₁₋ₓ S and Ni₃ S₄ , and the reactions become more sluggish for more metal deficient compositions. The study of oxidation kinetics of α-NiS is of metallurgical interest, as α-NiS related phases may occur when nickel ores are flash smelted to produce nickel matte. In an open air environment, the oxidation mechanisms of α-NiS are constant at 670 and 680 °C, dominated by the direct oxidation of α-NiS → NiO. The dominant oxidation mechanism changes to a chain reaction : α-NiS → [superscript k] ₁ Ni₃ S₂ → [superscript k] ₂ NiO at 700 °C. Therefore, different kinetic models need to be applied to these two distinct reaction mechanisms. Activation energy for the oxidation, α-NiS → NiO, in the temperature range 670 to 680 °C was calculated to be 868.2 kJ.mol⁻¹ using Avrami/Arrhenius method. Rate constant k₁ and k₂ are approximated to be 3 x 10⁻⁴ s⁻¹ and 5 x 10⁻⁴ s⁻¹ for the first part and second part of the chain reaction respectively at 700 ° C. The study of the variation in reaction rate with oxidation time illustrates the optimum oxidation time zone for each temperature, where NiO can be produced at the fastest rate. / Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering, 2005.