A baixa porcentagem de plantios com árvores do gênero Pinus no Brasil e a crescente demanda por polpa celulósica de fibra longa no país evidenciam a necessidade de estudos de espécies de pinus tropicais que se desenvolvam em regiões além do sul brasileiro. Os objetivos deste trabalho foram caracterizar tecnologicamente a madeira de Pinus maximinoi e avaliar o desempenho desta matéria-prima para produção de polpa celulósica, a partir do processo de polpação modificado do tipo Lo-Solids®. Utilizou-se como referência tecnológica a madeira de Pinus taeda, espécie mais empregada no país para produção de polpa celulósica de fibra longa. Foram analisadas 5 árvores de P. maximinoi e 5 árvores de P. taeda, com 14 anos de idade e plantadas nas mesmas condições edafoclimáticas. As madeiras das duas espécies foram caracterizadas tecnologicamente quanto a densidade básica da madeira, composição química e morfologia dos traqueídes. Posteriormente, foram realizados cozimentos de caracterização, utilizando-se o processo de polpação kraft convencional com diferentes níveis de cargas alcalinas, com o intuito de avaliar o desempenho da madeira de P. maximinoi frente ao processo de polpação e ajustar modelos matemáticos para estimar parâmetros de interesse . Foram obtidas polpas branqueáveis com número kappa = 28±5% a partir do processo de polpação modificado do tipo Lo-Solids®, com fator H 2295, sulfidez de 30% e relação licor madeira de 4L/kg. Os resultados de caracterização da madeira de P. maximinoi demonstraram que esta possui densidade básica equivalente a 0,417 g/cm3, teores de 64,49 % de holocelulose, 31,06% de lignina total, 4,45% de extrativos totais e 0,16% de cinzas e traqueídes com 4,19 mm de comprimento, 56,95 μm de largura, 44,11 μm de diâmetro de lúme e 6,42 μm de espessura da parede. Os resultados dos cozimentos Lo-Solids® mostraram que a madeira de P. maximinoi demandou álcali ativo de 24,4% (base NaOH) e resultou em polpas com rendimento depurado de 47,5%, teor de rejeitos de 0,43% e viscosidade de 713 cm3/g. O consumo específico da madeira de P. maximinoi foi de 5,868 m3/tsa e incremento médio anual em celulose de 6,575 tsa/ha/ano. O teor de sólidos gerados por tonelada de celulose produzida para a madeira de P. maximinoi foi de 1,451 t/tsa. Os resultados obtidos neste estudo permitem concluir que a madeira de P. maximinoi representa uma alternativa interessante para produção de polpa celulósica de fibra longa, tendo em vista que possui características tecnológicas muito semelhantes à madeira de P. taeda, além do menor consumo específico da madeira e maior incremento médio anual em celulose. / The low percentage of plantation of pine genus in Brazil and the growing demand for long fiber pulp demonstrates the necessity of studies with tropical pine species that develop in regions beyond the south of Brazil. The main objectives of this study were to characterize the wood of the specie Pinus maximinoi and to evaluate the performance of this material for pulp kraft production, using the modified pulping process Lo-Solids®. Pinus taeda wood was used as technologinal reference since it is the most used pine specie in Brazil for softwood pulp production. Samples from 5 Pinus maximinoi trees and 5 Pinus taeda trees were analysed both with 14 years old, planted in the same conditions. Both of the materials were technollogicaly characterized by wood basic density analysis, wood chemistry and tracheids morphology. After that, were realized characterization pulping processes, using the conventional kraft pulping process, with different alkali charges, in order to study the behavior of Pinus maximinoi wood throughout the process and ajust mathematical models to estimate parameters of interest. Then, it was produced bleached pulps with kappa number of 28±5% using the modified pulping process Lo-Solids®, with H factor 2295, 30% of sulfidity and liquor to wood ratio = 4L/kg. The results from the wood characterization shows that Pinus maximinoi wood has basic wood density equivalent to 0,417 g/cm3, 64,49% content of holocellulose, 31,06% content of total lignin, 4,45% content of total extractives and 0,16% content of ash; the tracheids morphology showed that the tracheids has lenght 4,19 mm, 56,95 μm of width, 44,11 μm of lumen width and 6,42 μm of wall thickness. The results of the Lo-Solids® pulping process showed that Pinus maximinoi wood has demanded alkali charge of 24,4% (NaOH) and resulted in pulps with screened yield of 47,5%, rejects contents of 0,43% and viscosity pulp of 713 cm3/g. The specific wood consumption was 5,868 m3/tsa and the IMACEL 6,575 tsa/ha/ano. The solids content generated per ton of cellulose was 1,451 t/tsa for Pinus maximinoi wood. The results obtained in this study showed that the Pinus maximinoi wood represents an interesting alternative for softwood pulp production given that the technological characteristics were very similar between the P. taeda wood, beyond the higher forestry production, the lower wood specific consumption observed and higher IMACEL.

This work reports the results of a systematic study of the factors that affect the bridging behaviour of bagasse. It shows that traditional bulk solids theory is inappropriate for predicting bagasse flow mainly because of the impossibility of obtaining a reliable measure of internal friction. It demonstrates the significant influence of fibre length and moisture content on its handling charateristics. Correlations of pertinent bulk properties such as compactibility, tensile strength, surface friction and translation of vertical into horizontal pressure have been developed. These were derived as a result of measurements in equipment that was designed for the purpose. Finally, an empirical model utilising these correlations is proposed by which the likelihood of bridge formation in any piece of bagasse handling equipment can be determined. The validity of the model is assessed by comparison with bridging tests that were performed under controlled conditions. / Thesis (Ph.D.)-University of Natal, 1996

A baixa porcentagem de plantios com árvores do gênero Pinus no Brasil e a crescente demanda por polpa celulósica de fibra longa no país evidenciam a necessidade de estudos de espécies de pinus tropicais que se desenvolvam em regiões além do sul brasileiro. Os objetivos deste trabalho foram caracterizar tecnologicamente a madeira de Pinus maximinoi e avaliar o desempenho desta matéria-prima para produção de polpa celulósica, a partir do processo de polpação modificado do tipo Lo-Solids®. Utilizou-se como referência tecnológica a madeira de Pinus taeda, espécie mais empregada no país para produção de polpa celulósica de fibra longa. Foram analisadas 5 árvores de P. maximinoi e 5 árvores de P. taeda, com 14 anos de idade e plantadas nas mesmas condições edafoclimáticas. As madeiras das duas espécies foram caracterizadas tecnologicamente quanto a densidade básica da madeira, composição química e morfologia dos traqueídes. Posteriormente, foram realizados cozimentos de caracterização, utilizando-se o processo de polpação kraft convencional com diferentes níveis de cargas alcalinas, com o intuito de avaliar o desempenho da madeira de P. maximinoi frente ao processo de polpação e ajustar modelos matemáticos para estimar parâmetros de interesse . Foram obtidas polpas branqueáveis com número kappa = 28±5% a partir do processo de polpação modificado do tipo Lo-Solids®, com fator H 2295, sulfidez de 30% e relação licor madeira de 4L/kg. Os resultados de caracterização da madeira de P. maximinoi demonstraram que esta possui densidade básica equivalente a 0,417 g/cm3, teores de 64,49 % de holocelulose, 31,06% de lignina total, 4,45% de extrativos totais e 0,16% de cinzas e traqueídes com 4,19 mm de comprimento, 56,95 μm de largura, 44,11 μm de diâmetro de lúme e 6,42 μm de espessura da parede. Os resultados dos cozimentos Lo-Solids® mostraram que a madeira de P. maximinoi demandou álcali ativo de 24,4% (base NaOH) e resultou em polpas com rendimento depurado de 47,5%, teor de rejeitos de 0,43% e viscosidade de 713 cm3/g. O consumo específico da madeira de P. maximinoi foi de 5,868 m3/tsa e incremento médio anual em celulose de 6,575 tsa/ha/ano. O teor de sólidos gerados por tonelada de celulose produzida para a madeira de P. maximinoi foi de 1,451 t/tsa. Os resultados obtidos neste estudo permitem concluir que a madeira de P. maximinoi representa uma alternativa interessante para produção de polpa celulósica de fibra longa, tendo em vista que possui características tecnológicas muito semelhantes à madeira de P. taeda, além do menor consumo específico da madeira e maior incremento médio anual em celulose. / The low percentage of plantation of pine genus in Brazil and the growing demand for long fiber pulp demonstrates the necessity of studies with tropical pine species that develop in regions beyond the south of Brazil. The main objectives of this study were to characterize the wood of the specie Pinus maximinoi and to evaluate the performance of this material for pulp kraft production, using the modified pulping process Lo-Solids®. Pinus taeda wood was used as technologinal reference since it is the most used pine specie in Brazil for softwood pulp production. Samples from 5 Pinus maximinoi trees and 5 Pinus taeda trees were analysed both with 14 years old, planted in the same conditions. Both of the materials were technollogicaly characterized by wood basic density analysis, wood chemistry and tracheids morphology. After that, were realized characterization pulping processes, using the conventional kraft pulping process, with different alkali charges, in order to study the behavior of Pinus maximinoi wood throughout the process and ajust mathematical models to estimate parameters of interest. Then, it was produced bleached pulps with kappa number of 28±5% using the modified pulping process Lo-Solids®, with H factor 2295, 30% of sulfidity and liquor to wood ratio = 4L/kg. The results from the wood characterization shows that Pinus maximinoi wood has basic wood density equivalent to 0,417 g/cm3, 64,49% content of holocellulose, 31,06% content of total lignin, 4,45% content of total extractives and 0,16% content of ash; the tracheids morphology showed that the tracheids has lenght 4,19 mm, 56,95 μm of width, 44,11 μm of lumen width and 6,42 μm of wall thickness. The results of the Lo-Solids® pulping process showed that Pinus maximinoi wood has demanded alkali charge of 24,4% (NaOH) and resulted in pulps with screened yield of 47,5%, rejects contents of 0,43% and viscosity pulp of 713 cm3/g. The specific wood consumption was 5,868 m3/tsa and the IMACEL 6,575 tsa/ha/ano. The solids content generated per ton of cellulose was 1,451 t/tsa for Pinus maximinoi wood. The results obtained in this study showed that the Pinus maximinoi wood represents an interesting alternative for softwood pulp production given that the technological characteristics were very similar between the P. taeda wood, beyond the higher forestry production, the lower wood specific consumption observed and higher IMACEL.

The fluids that are operated above their critical temperature and pressure are known as supercritical fluids (SCFs). SCFs replaces the conventional organic solvents in the chemical processes due to their attractive properties such as liquid like densities, gas like diffusivities, negligible surface tension, lower viscosity and high compressibility. Carbon dioxide, being non-toxic, non-flammable with ambient critical temperature and moderate critical pressure, is the most widely used SCF in many chemical processes. Supercritical carbon dioxide (SCCO2) finds applications in industrial processes such as extraction and separation processes. The feasibility of a supercritical process can be determined from the solubility of solute in SCF. For the efficient design of a SCF process, the effects of temperature and pressure on the solubility of a solid should be examined thoroughly. In general, the solute of interest is not present alone; it is present along with many other components in the compound. The solute has to be extracted or separated from matrix of components. Therefore, it is important to determine the mixture solubilities in SCCO2. The mixture solubility of a solute is not same as that of pure component solubility. The presence of the other component alters the solubility of the solute to a greater extent; hence the effects of the other components present along with the solute, temperature and pressure need to be known to understand the mixture behavior of the solute in SCCO2. The solubilities of solid isomers (ortho-, meta-, para-) in SCCO2 vary to a greater extent. This huge difference in the solubilities of isomers is due to interactions between the molecules. The high solubility of an isomer in SCCO2 might be due to the solute-solvent interactions. The interactions between the molecules are significant in the solid mixtures solubilities in SCCO2. This research work focuses on experimental determination and modeling of mixture solubilities of solids in SCCO2. The solubilities of several pairs of isomers have been experimentally determined at different temperatures and pressures. These include the ternary solubilities of ntrophenols, nitrobenzoic acids and dihydroxy benzene isomers mixtures in SCCO2. The experimental solubilities of nitrophenol (meta- and para-) isomers mixture have been determined. This study includes the effect of temperature, pressure and each isomer on the ternary mixture solubilities of nitrophenol mixtures. The enhancements in the ternary solubilities of nitrophenols over their binary solubilities and the selectivity of SCCO2 for the nitrophenol mixture have been discussed in detail. The solubilities of dihydroxy benzene (ortho-: pyrocatechol, meta- : resorcinol and para-: hydroquinone) isomers in SCCO2 have been determined at various temperatures and pressures. The ternary solubilities of pyrocatechol and resorcinol and quaternary solubilities of pyrocatechol, resorcinol and hydroquinone mixtures in SCCO2 have been investigated. The effect of each isomer on the mixture solubilities of other isomers has been included in this work. Selectivity for dihydroxy benzene isomers and variation of solubilities enhancements with temperature and pressure has been presented in this study. The equilibrium mixture solubilities of nitrobenzoic acid isomers (meta- and para) mixture have been studied. The variation of mixture solubilities and their enhancements with temperature and pressure has been thoroughly analyzed. Selectivity of SCCO2 for this nitrobenzoic acid mixture has been studied in detail. The increase or decrease in the ternary solubilities of the solid mixtures that have been considered in this study is due to the interactions between the molecules. The ternary solubilities of m-nitrophenol increase whereas they decrease for pnitrophenol for the nitrophenol solid mixture. Quaternary solubilities of dihydroxy benzene isomers (pyrocatechol + resorcinol + hydroquinone) increases compared to their pure component solubilities. The ternary solubilities of pyrocatechol increases while resorcinol decreases over the pressure range at different temperatures (except 338 K) considered in this study. The mixture solubilities of p-nitrobenzoic acid of nitrobenzoic acid isomers increase to a greater extent. An average of separation efficiency of 70%, 85% and 90% has been observed for ternary solid mixtures of nitrophenol, nitrobenzoic acid and dihydroxy benzene isomers respectively. Modeling of high pressure multi-component systems is useful to understand the behavior of the mixtures. Moreover, the experimental determination of multicomponent solubilities of solids in SCCO2 is tedious and time consuming; hence the modeling of mixture solubilities is essential. The interactions between the molecules have been incorporated in the association theory and a five parameter equation with two constraints has been derived for binary systems. The new equation correlates the solubilities of m-dinitrobenzene in this study along with 72 other systems available in literature. Seven new model equations have been developed to correlate ternary (2 for cosolvent (solid + cosolvent + SCCO2) systems; 5 for solid mixtures in SCCO2) solubilities of solids in SCCO2. A new model equation for cosolvent ternary systems has been derived by using the concepts of association of molecules. The model equation contains seven adjustable parameters with three constraints and correlates mixture solubilities in terms of temperature, pressure, density and cosolvent composition. The interactions between the molecules have been included in the association theory then the number of parameters decreased to five with two constraints. The performance of the newly developed equations has been evaluated for 32 ternary systems with various cosolvents along with experimental data of mdinitrobenzene in methanol cosolvent of this study. The same association theory has been extended to ternary (solid mixtures + SCCO2) solubilities of solids in SCCO2 and two new equations have been derived with and without incorporating interactions between the molecules. Both the equations have five adjustable parameters with three constraints for the equation which has been derived from association theory alone and two constraints for the equation which has been derived by considering the interactions between the molecules in the association theory. A new model equation has been derived by combining solution model with Wilson activity coefficient model to account for nonidealities of the solute. This equation has four adjustable parameters and no constraints on the parameters. The non-idealities of both solutes in the solution model have been included and two more equations with no constraints on the parameters have been developed. One equation uses NRTL activity coefficient model which results in three adjustable parameters while the other equation with five parameters has been obtained from Wilson activity coefficient model for solid mixtures solubilities in SCCO2. The performance of the newly developed equations has been evaluated for the solid mixtures (ternary systems) in SCCO2. The equations with constraints make them limited for few systems and the equations with no constraints are able to correlate the solubilities of solids of all the ternary systems that are available in literature along with the generated ternary experimental data of this study. The quaternary solubilities of solids have been correlated by using a five parameter model equation which has been derived by combining solution and Wilson activity coefficient models. The equation for the quaternary systems does not have constraints on the parameters; hence can be applied for quaternary systems. The equation correlates the quaternary solubilities of solids in terms of temperature, pressure, density and cosolute compositions. Chapter 1 gives a brief introduction on the solubilities of solid mixtures and their behavior in SCCO2. Chapter 2 presents the experimental setup and the solubility data of binary, ternary and quaternary systems determined in this study. Chapter 3 focuses on the models that have been derived to correlate the solubilities of solids in SCCO2. Chapter 4 discusses in detail about the results obtained in this research work. Chapter 5 briefly summarizes the work and presents major conclusions. The new equations that have been developed here are first of its kind for the ternary and quaternary systems. These equations give information about the nonidealities of the systems. The nature of the interactions between the molecules can be determined from the parameters of the equations which incorporate interactions between the molecules. The multi-component solubilities of the solids can be correlated by using the semi-empirical equations that have been derived in this research.

The thesis entitled "Phase Behaviour in Crystalline Solids: Exploring the Structure Guiding Factors via Polymorphism, Phase Transitions and Charge Density Studies" consists of five chapters divided into two parts. A basic introductory section describes the topics relevant to the work and the methods and techniques utilized. Part A contains two chapters that discuss the structural aspects related to polymorphism, solvatomorphism, conformational preferences and phase transitions exhibited by active pharmaceutical ingredients (APIs). It also discusses the structure-property correlations in API crystal forms and the possible utility of second harmonic generation (SHG) for their bulk characterization. Part B has three chapters that discuss experimental and theoretical charge density analyses of intra-and intermolecular interactions that play structure guiding roles in some of the APIs discussed in Part A. The main focus of the present work is to characterize the interaction patterns devoid of strong classical hydrogen bonds. The case studies include multifurcated C - H …O hydrogen bonds, the “carbon bonding” and chalcogen interactions involving Se and S atoms. In addition to charge density studies, in situcryocrystallography and molecular complexation experiments have been employed to examine structural consequences of chalcogen bonding. Further, Appendices 1 and 2 describe phase transition studies on the inorganic mineral kröhnkite and its high temperature phase transitions leading to novel inorganic structural types. Part A: Polymorphism and phase behaviour in Active Pharmaceutical Ingredients (APIs) Chapter 1 discusses case studies of polymorphism, supramolecular preference sand phase transitions exhibited by active pharmaceutical ingredients (APIs). Section 1.1 deals with the polymorphism of an anti-oxidant drug candidate ebselen and its hydroxyl derivative. The potential of organoselenium compounds to form a Se…O chalcogen bonded supramolecular recognition unit (synthon) has been established in these polymorphs and its generality is substantiated with the help of a Cambridge Structural Database (CSD) analysis. Section 1.2 demonstrates the utility of the ‘chalcogen bonded supramolecularsynthon’ in generating molecular complexes of APIs. A series of salts and co-crystals of the amyotrophic lateral sclerosis drug Riluzole have been synthesized in order to evaluate the structure directing role of S…O chalcogen bonded synthon in their crystal structures. Section 1.3adescribes the generation of polymorphs and solvatomorphs of the antidepressant drug candidate fenobamand associated phase transitions. The tautomeric preference in this molecule has been rationalized from the crystal structure analysis and abinitioenergy calculations. Further, section 1.3b utilizes chemical derivatization as a means to experimentally simulate thetautomeric preference and molecular conformations in several derivatives of fenobam and thiofenobam. Section 1.4 describes the issue of solvatomorphism and the generation of the fifth solvatomorph of gallic acid, its structural complexity and temperature induced phase transitions. The ability of solvent water molecules to drive structural diversity, by forming ‘hydration synthons’,is demonstrated in this case. Chapter 2 presents a novel methodology for the detection of polymorphic impurities in APIs based on second harmonic generation (SHG).The SHG based method has been employed to polymorphic mixtures of fenobam, hydrochlorothiazide, pyrazinamide, tolbutamide, curcumin, febuxostat and nimesulide.The conventional methods such as powder X-ray diffraction (profile fitting analysis), FT-IR, Raman spectroscopy and thermal analysesto detect the presence of polymorphic impuritiesin bulk API samples are employed on the mixtures of these API samples and the impurity detection limits are compared with the proposed SHG methodology. The APIs used in these case studies were screened for their SHG efficiency using quantum chemical calculations of hyperpolarizability and HOMO-LUMO charge redistribution behaviour. Further, a correlation with the crystal symmetry, relative packing arrangement of molecules and the observed SHG efficiency have been discussed in of some of these cases. Part B: Exploring the nature and structural consequences of nonbonding interactions in molecular crystals Chapter 3 discusses the electron density features of quasi-trifurcated CH…Cl/CH…O interaction motifs leading to ‘carbon bonding’ and a trifurcated CH…O hydrogen bond motif. Section 3.1 describes the experimental and theoretical charge density analyses of quasi-trifurcated CH…Cl and CH…O motifsand investigates the existence of “carbon bonding” in solid state. The experimental charge density evidence for “carbon bonding” have been analyzed in cases of fenobam and dimethylamine: 4-hydroxybenzoic acid complex. The existence of this unconventional interaction, which roughly mimics the transition state geometry of SN2 (bimolecular nucleophilic substitution) reaction, is further established by a CSD analysis. Section 3.2 describes the experimental and theoretical charge density analyses of ferulic acid and compares the topological features associated with a trifurcated CH…O hydrogen bond motif, with corresponding strong classical OH…O hydrogen bonds. The study demonstrates the “Gulliver effect” of weak interactions in charge density terms. Charge density based interaction energy calculations via EPMM and EML methods have been utilized in this context to evaluate the relative strength of such interactions. Chapter 4 discusses the charge density features of intermolecular chalcogen bonding interactions involving selenium and sulphur atoms.Section 4.1 describes the experimental and theoretical charge density analyses of ebselen and its hydroxyl derivative. The charge density characterization of the conserved chalcogen bond synthon (discussed in chapter 1, section 1.1) has been carried out and electronic nature and geometric dependence of Se…O interactions have been explored. The mechanism of drug action of ebselen has been correlated with the experimentally observed charge density distribution around the intramolecular SeC and SeN bonds. Section 4.2 explores the homochalcogen interactions such as S…SandSe…Se in phenol analogues. In situ cryocrystallographic studies on thiophenol, selenophenol and their solid solutions are described. Veggard’s law-like behaviour observed in these solid solutions have been rationalized and the S…S and Se…Sehomochalcogen interactions have been evaluated in these liquid systems which are devoid of any other packing forces such as strong hydrogen bonds. Chapter 5 discusses the conformation locking potential of intramolecular S…O chalcogen bonding in sulfadrugs. Section 5.1 discusses conformation locking in the antibioticdrugsulfamethizole. A two pronged approach has been adopted in the study; a) generation of cocrystals and salts of sulfamethizole for the ‘experimental simulation’ of the molecular conformation, b) evaluation of charge density distribution around the intramolecular S…O interaction region in sulfamethizole. Section 5.2 describes the effect of ‘simple hybridized orbital geometry’ in the formation of intramolecular S…O chalcogen bonding. The experimental charge density analysis of the carbonic anhydrase inhibitor drug acetazolamide has been carried out and the two different intramolecular S…O geometries have been compared in terms of the charge density topology. The analysis highlights the advantage of “orbital geometry” consideration over the conventional distance-angle criteria in assessing nonbonded interactions.

Optically-transparent solids have a significant role in many emerging topics of fundamental and applied research, in areas related to Applied Optics and Photonics. In the functional devices based on them, the presence of ‘time-varying temperature fields’ critically limit their achievable performance, when used particularly for high power laser-related tasks such as light-generation, light-amplification, nonlinear-harmonic conversion etc. For optimization of these devices, accurate knowledge of the material thermal parameters is essential. Many optical and non-optical methods are currently in use, for the reliable estimation of the thermal parameters. The thermal diffusivity is a key parameter for dealing with ‘transient heat transport’ related problems. Although its importance in practical design for thermal management is well understood, its physical meaning however continues to be esoteric. The present effort concerns with a few investigations on the “Optical interrogation of ‘transient thermal conduction’ in dielectric solids”. In dielectric solids, the current understanding is that the conductive heat transport occurs only through phonons relevant to microscopic lattice vibrations. Introducing for the first time, a virtual linear translator motion as the basis for heat conduction in dielectric materials, the present investigation discusses an alternative physical mechanism and a new analytical model for the transient heat conduction in dielectric solids. The model brings into limelight a ‘new law of motion’ and a ‘new quantity’ which can be defined at every point in the material, through which time-varying heat flows resulting in time-varying temperature. Physically, this quantity is a measure for the linear translatory motion resulting from transient heat conduction. For step-temperature excitation it bears a simple algebraic relation to the thermal diffusivity of the material. This relationship helps to define the thermal diffusivity of a dielectric solid as the “translatory motion speed” measured at unit distance from the heat source. A novel two-beam interferometric technique is proposed and corroborated the proposed concept with significant advantages. Two new approaches are introduced to estimate thermal diffusivity of optically transparent dielectric solid; first of them involves measurement of the position dependent velocity of isothermal surface and second one depend on the measurement of position dependent instantaneous velocity of normalized moving intensity points. A ‘new mechanism’ is proposed and demonstrated to visualize, monitor and interrogate optically, the ‘linear translatory motion’ resulting from the transient heat flow due to step- temperature excitation. Two new approaches are introduced, first one is ‘mark’ and ‘track’ approach, it involves a new interaction between sample supporting unsteady heat flow with its ambient and produces optical mark. Thermal diffusivity is estimated by tracking the optical mark. Second one involves measurement of instantaneous velocity of optical mark for different step-temperature at a fixed location to estimate thermal diffusivity. A new inverse method is proposed to estimate thermal diffusivity and thermal conductivity from the volumetric specific heat capacity alone through thought experiment. A new method is proposed to predict volumetric specific heat capacity more accurately from thermal diffusivity.

Experimental studies have shown that the yield strength of many important engineering materials such as polymers, ceramics and metallic glasses is dependent on hydrostatic stress. In addition, these materials may also exhibit plastic dilatancy. These deviations from the assumptions of classical plasticity theories have also been observed for some metallic alloys, although to a lesser extent compared to non-metals. In pressure independent plastic solids, it has been found that the level of crack tip constraint can affect the near-tip stress and deformation fields and hence the fracture resistance. The objective of the present work is to study the effects of pressure sensitive yielding, plastic dilatancy and constraint loss on the ductile fracture processes under mode-I conditions. Further, the three-dimensional (3D) structure of elastic-plastic near-crack front fields in a pressure independent plastic solid under mixed mode (combined modes I and II) loading is also examined. A finite element study of 3D crack tip fields in pressure sensitive plastic solids under mode-I, small scale yielding (SSY) conditions is first carried out. The material is assumed to obey a small strain, Extended Drucker-Prager (EDP)yield criterion. The roles of pressure sensitive yielding, plastic dilatancy and yield locus shape on the 3D plastic zone development and near-crack front fields are systematically investigated. It is found that while pressure sensitivity leads to a significant drop in the hydrostatic stress all along the 3D crack front, it enhances the plastic strain and crack opening displacements. However, plastic incompressibility results in elevation of both near-tip hydrostatic stress and notch opening. The implications of these observations on micro-void growth and interaction near a notch tip are studied in detail subsequently. The effects of constraint loss on void growth near a notch tip under mode-I loading in materials exhibiting pressure sensitive yielding and plastic dilatancy are investigated by performing large deformation elastic-plastic finite element analyses. To this end, two-dimensional (2D)plane strain and 3Dmodified boundary layer formulations are employed by prescribing the elastic K-T field as remote boundary conditions. The results are generated for different combinations of K (or J ) and T -stress. The material is assumed to obey a finite strain, EDP yield condition. The distributions of hydrostatic stress and plastic strain in the ligament connecting the notch and a nearby void (cylindrical or spherical) as well as the growth of the notch and the void are studied. The results show that void growth with respect to J is enhanced due to pressure sensitivity, and more so when the plastic flow is non-dilatational, which corroborates with the trends exhibited by the 3D crack tip fields. However, the evolution of ductile fracture processes like void growth, plastic strain localization and ligament length reduction with respect to J is retarded in the case of spherical voids. Further, irrespective of pressure sensitivity, loss of crack tip constraint can significantly slow down void growth. The effects of pressure sensitive yielding and plastic dilatancy on near-tip void growth and multiple void interaction mechanisms in single edge notched bend (SENB) and center cracked tension (CCT) specimens which display high and low constraint levels, respectively, are investigated next. It is observed that the latter mechanism which is favored by high initial porosity is further accelerated by pressure sensitive yielding and high constraint. The predicted resistance curves based on a simple void coalescence mechanism show enhancement in fracture resistance when constraint level is low and when pressure sensitivity is suppressed. Finally, detailed elastic-plastic finite element simulations are carried out using a boundary layer (SSY) formulation to investigate the 3D nature of near-crack front fields in a von Mises solid under mixed mode (combined modes I and II)loading. The plastic zones and radial, angular and thickness variations of the stresses are studied corresponding to different levels of remote elastic mode mixity and applied load, as measured by the plastic zone size with respect to the plate thickness. The 3D results are compared with those obtained from 2D simulations and asymptotic solutions to establish the validity of 2D plane stress and plane strain approximations near a crack front. It is found that, in general, plane stress conditions prevail at a distance from the crack front exceeding half the plate thickness, although it could be slightly smaller for mode-II predominant loading.

PONTES FILHO, Frederico Silva Thé. Qualidade de cajus tratados com aminoetoxivinilglicina (AVG) e ácido geberélico (GA3). 2014. 138 f. : Tese (doutorado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Fitotecnia, Pós-Graduação em Agronomia / Fitotecnia, Fortaleza-CE, 2014 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-22T12:56:23Z No. of bitstreams: 1 2014_tese_fstpontesfilho.pdf: 2483621 bytes, checksum: c0b7ea622f4ea9e6f88cfd7aeca00ab3 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-22T12:57:05Z (GMT) No. of bitstreams: 1 2014_tese_fstpontesfilho.pdf: 2483621 bytes, checksum: c0b7ea622f4ea9e6f88cfd7aeca00ab3 (MD5) / Made available in DSpace on 2016-08-22T12:57:05Z (GMT). No. of bitstreams: 1 2014_tese_fstpontesfilho.pdf: 2483621 bytes, checksum: c0b7ea622f4ea9e6f88cfd7aeca00ab3 (MD5) Previous issue date: 2014 / One of many problems that worry the cashew farmers is the very short post-harvest conservation of the peduncle, due to the fast firmness lost, negatively affecting the sales of this product. The use of growth regulators may be an alternative to improve the peduncle quality (keep flesh firmness), avoid waste (reduce the pre-harvest fall), increase the harvest time (reduce the seasonality), this way, dropping production costs in the cashew farming. The aim of this study was to evaluate the effect of AVG and GA3 spraying in pre-harvest, concerning the quality and production of pseudo fruits of dwarf cashew tree clones CCP 76 and 189, produced in the Northeast Brazilian Region. Thereunto, it was made five experiments, which the replications was the harvests times, for each treatment. The first was carried in randomized block, with two plants per unit and 10 fruits per plant, with following treatments (doses) for the CCP 76 clone: AVG 0 mg L-1 (water sprayed); AVG 40 mg L-1; AVG 80 mg L-1; AVG 120 mg L-1; GA3 40 mg L-1; GA3 80 mg L-1; and GA3 120 mg L-1. The studied characteristics was power of hydrogen (pH), soluble solids (SS), titratable acidity (AT), SS/AT relation, soluble sugar (AS), vitamin C (VC), total carotenoids (CT), total anthocyanins (ANT) and extractable polyphenols (PE). The second and the third experiments were carried in randomized blocks, with two plants per unit and 15 fruits per plant and two clones (CCP 76 and BRS 189). These experiments include the following treatments (doses): AVG and GA3 0 mg L-1 (water sprayed); 60 mg L-1, 120 mg L-1, 180 mg L-1 of AVG and 60 mg L-1, 120 mg.L-1, 180 mg.L-1 of GA3. For both clones the characteristics evaluated was break between spray and harvest, fruit fall before harvest, peduncle size, peduncle basal diameter, peduncle top diameter, cashew total mass, peduncle mass, nut mass and peduncle flesh firmness. The fourth and fifth experiments had same treatments and experimental set of the second and third. However the evaluated variables, for both clones, was: SS, AT, SS/AT relation, AS and VC. In the first experiment it was observed that the GA3 120 mg L-1 dose could be a alternative for the early dwarf cashew clone CCP 76, because it improved the commercial quality attributes of the peduncles. In the experiments two and three GA3 increased the break between the spraying and the harvest, the size and firmness of clones peduncles studied. In the two last experiments the GA3 increased the SS/AT relation of the peduncles of CCP 76 and BRS 189 early dwarf cashew clones. Therefore, besides it detain the maturation time, the growth regulators also improved some quality attributes of the peduncles, what is well wished due to the fact that the improvement of such attributes is predominantly made by genetic improvement, and this process, in the current conditions, takes a lot of time to be concluded. / Um dos vários problemas que preocupam os cajucultores, especialmente os que pretendem atuar no comércio de caju in natura, é a conservação pós-colheita demasiadamente pequena dos pedúnculos, atribuída à rápida perda de firmeza dos mesmos, afetando negativamente a venda desse pseudofruto. O uso de reguladores de crescimento pode ser uma alternativa para melhorar a qualidade do pedúnculo (manter a firmeza da polpa), evitar o desperdício (diminuir a queda pré-colheita), aumentar o tempo de colheita (abreviar a sazonalidade), desse modo, reduzindo custo de produção na cajucultura. O objetivo do trabalho foi avaliar o efeito da aplicação de AVG e GA3 em pré-colheita, sobre a qualidade e produção dos pseudofrutos dos clones de cajueiro-anão-precoce CCP 76 e BRS 189, cultivados na região Nordeste do Brasil. Para tanto, foram realizados cinco experimentos, sendo as repetições as datas de colheita, para cada tratamento. O primeiro foi realizado em blocos casualizados, com duas plantas por parcela e 10 frutos por planta, com os seguintes tratamentos (dosagens) para o clone CCP 76: 0 mg L-1 de AVG e GA3 (pulverização com água); 40 mg L-1 de AVG; 80 mg L-1 de AVG; 120 mg L-1 de AVG; 40 mg L-1 de GA3; 80 mg.L-1 de GA3; e 120 mg.L-1 de GA3. As características analisadas foram: potencial hidrogeniônico (pH), sólidos solúveis (SS), acidez titulável (AT), relação sólidos solúveis/acidez titulável (SS/AT), açúcares solúveis (AS), vitamina C (VC), carotenoides totais (CT), antocianinas totais (ANT) e polifenois extraíveis (PE). O segundo e terceiro experimentos foram realizados em blocos casualizados, com duas plantas por parcela, 15 frutos por planta e dois clones de cajueiro (CCP 76 e BRS 189). Esses experimentos abrangeram os seguintes tratamentos (dosagens): 0 mg L-1 de AVG e GA3 (pulverização com água); 60 mg L-1 de AVG; 120 mg L-1 de AVG; 180 mg L-1 de AVG; 60 mg L-1 de GA3; 120 mg.L-1 de GA3; e 180 mg.L-1 de GA3. As características analisadas, para ambos os clones, foram: intervalo entre a aplicação e colheita, queda de frutos em pré-colheita, comprimento do pedúnculo, diâmetro basal do pedúnculo, diâmetro apical do pedúnculo, massa total do caju, massa do pedúnculo, massa da castanha e firmeza da polpa do pedúnculo. O quarto e quinto experimentos tiveram os mesmos tratamentos e delineamento experimental do segundo e terceiro. Contudo as variáveis analisadas, para ambos os clones, foram: SS, AT, relação SS/AT, AS e VC. No primeiro experimento verifica-se que a dosagem de 120 mg L-1 de GA3 pode ser uma alternativa ao clone de cajueiro-anão-precoce CCP 76, pois melhora os atributos de qualidade comercial dos pedúnculos. Nos experimentos dois e três o GA3 aumentou o intervalo entre a aplicação e colheita, tamanho e a firmeza dos pedúnculos dos clones estudados. Nos dois últimos experimentos o GA3 aumentou a relação SS/AT dos pedúnculos dos clones de cajueiro-anão-precoce CCP 76 e BRS 189. Portanto, além de terem retardado o tempo de maturação, os reguladores de crescimento também aprimoram alguns atributos de qualidade dos pedúnculos, o que é bastante desejável devido ao fato de que a melhoria de tais atributos é feita predominantemente via melhoramento genético, e este processo, nas atuais condições, leva muito tempo até ser concluído.

Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1978 / Includes bibliographical references. / Elec. E. / Elec. E. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science

Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1978 / Includes bibliographical references. / by Patricia E. Clark. / B.S. / B.S. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science