Étant donné son origine, le bois reste biodégradable et a besoin d'être protégé contre les agents abiotiques et biotiques afin d'avoir une longue durée de service. Les associations entre les tanins et l'acide borique peuvent être considérés comme un traitement innovant et respectueux de l'environnement. Ces formulations aqueuses de tannins et d'acide borique augmentent la rémanence du bore dans le bois traité. De plus, le bore est partiellement fixé au réseau polymère de tannins autocondensés dans le bois et garde suffisamment de mobilité pour garder son efficacité biologique. Ces associations ont été testées pour une application en extérieur, au-dessus et dans le sol, et pour leurs propriétés ignifugeantes. Une première formulation de tannin-hexamine et acide borique a montré une efficacité certaine face aux dégradations biologiques et au feu. Le comportement au vieillissement naturel et artificiel, au lessivage à l'échelle du laboratoire, ainsi que l'efficacité biologique résultante, de bois traité par ces associations a été étudié. Les résultats montent que ces trois vieillissements mènent à des performances biologiques différentes, toutes liées à la teneur en bore résiduelle. Une formulation tannin-bore dite améliorée, contenant du ɛ-caprolactame pour rendre le réseau polymère plus flexible (et éviter les craquelures comme dans la première formulation) a été étudiée pour les mécanismes chimiques mis en jeu, la résistance biologique au-dessus et dans le sol, et la résistance au feu. Le polymère à base de tannin acquiert une structure plus élastique après incorporation de ɛ-caprolactame, comme démontré par des analyses FT-IR. La résistance biologique du bois traité procure une résistance à long terme en extérieur, même dans le sol. L'effet de protection au feu est moins intéressant que pour la première formulation, mais reste toute de même plus important que pour le témoin. Afin d'améliorer l'efficacité des associations entre bore et tannins, l'élaboration de bois contenant un polymère nano-composite (Wood Tannin NanoComposite, WTNC) utilisant tannins, acide borique et montmorillonite a été étudiée. Des analyses FT-IR et XRD on permit d’identifier des nanoparticules d'argiles dans le WTNC. Par ailleurs, des traces de montmorillonite dans les parois du bois ont été observées en microscopie électronique à balayage. Par comparaison avec des témoins, la résistance à la compression du WTNC est plus importante, l'absorption d'eau et l'aptitude au collage du WTNC dépend de l'essence utilisée (pin sylvestre vs. Hêtre), la stabilité dimensionnelle du WTNC est légèrement abaissée et sa mouillabilité significativement réduite. La résistance à l'attaque de champignons et termites est améliorée dans des proportions variables selon que l'on utilise du pin sylvestre ou du hêtre. Les performances anti-feu des WTNC sont affectées différemment en fonction de l'essence de bois utilisée et des paramètres considérés. Cette étude analyse aussi les impacts environnementaux de la production de produit de préservation tannin-bore (pour la première formulation) et compare aussi les impacts du berceau à la tombe dans le cadre d'une analyse de cycle de vie de bois traité par cette formulation, en comparaison avec 2 formulations industrielles et du béton. Il apparaît que même si ces associations tannin-bore peuvent être encore étudiées plus avant et plus finement du point de vue chimique, pour leurs performances biologiques (vis-à-vis d'insectes coléoptères, essais de champ avec des termites, moisissures…), ainsi que pour leur profil éco-toxicologique, elles ont montré de réelles améliorations du bois dans les domaines de la résistance biologique et de la résistance au feu. / Due to its origins, wood remains biodegradable and needs to be protected against abiotic and biotic agents for a long service life. Tannin-boron associations can be considered as an innovative preservative formulation and environmentally-friendly treatment. These waterborne associations of tannins and boric acid increase the permanence of boron in the wood. Furthermore, boric acid is partly fixed to the network of autocondensed tannin in the wood and keeps sufficient mobility to maintain its biological action. These associations have been investigated for their outdoor applications, both above and in-ground, as well as for their ability for fire protection. An original formulation of tannin-hexamine and boric acid, has shown efficiency against biological attack and fire degradation. The natural and artificial weathering behaviour, and laboratory scale leaching, of such treated wood have been investigated, and followed by biological tests. The results showed that the weatherings led to different performances, always linked with the amount of remaining boron. An advanced tannin-boron formulation including ɛ-caprolactam to make the polymer network more flexible (and avoiding cracks as noticed for the original formulation) was studied for the chemical mechanisms, biological resistance above and in-ground, fire retardancy. The tannin polymer acquires a more elastic structure after adding ɛ-caprolactam, as seen with FT-IR analyses. The biological resistance of the treated wood provided a long lasting protection against degradation in outdoor exposures, and even in ground contact. However, fire retardant effect of this advanced tannin-boron preservative was negatively influenced with comparison to the original tannin-boron formulation, but still better than control. In order to improve the associations between boron and tannin for wood protection, the conception of wood polymer nanocomposite using tannin, boric acid and montmorillonite tentatively carried out. The analyses of FT-IR and XRD have investigated to identify nanoclay in Wood Tannin Nanocomposite (WTNC). Meanwhile, the trace of montmorillonite in wood cell is also captured by SEM. By comparison with control, compression strengths of WTNC samples increase; water absorption and gluing ability of WTNC depend on the wood species used (Scot Pine vs. Beech); dimensional stability of WTNC is slightly decreased, and wettability was significantly decreased. Fungal and termite resistance of WTNC are improved to different extends if Scots pine or beech samples are used. Fire performances of WTNC is affected differently depending on the wood species used and the parameters considered. This study also analyses the environmental impacts of producing tannin-boron (TB) preservative (the original formulation) and comparatively introduces the cradle-to-grave life cycle environmental impacts (LCA) of TB-treated timber as landscaping materials, compared with 2 industrial formulations and concrete.Even if all these tannin-boron association systems developed still need to be improved for some point of their chemistry, biological performances (coleoptera insects, field tests with termites, molds…), as well as for their eco-toxicological profile, they have shown to improve the biological and fire resistance of the wood.

Inferential control of boric acid production system using the reaction of colemanite with sulfuric acid in four continuously stirred tank reactors (CSTR) connected in series is aimed. In this control scheme, pH of the product is measured on-line instead of boric acid concentration for control purposes. An empirical correlation between pH and boric acid concentration is developed using the collected data in a batch reacting system in laboratory-scale and this correlation is utilized in the control system for estimator design. The transfer function model of the 4-CSTR system previously obtained is used in the MPC controller design. In the experiments done previously for the modelling of 4-CSTR system, it was observed that the reaction goes complete within the first reactor. Therefore, the control is based on the measurements of pH of the second reactor by manipulating the flow rate of sulfuric acid given to the first reactor, while the flow rate of colemanite fed to the system is considered as disturbance. The designed controller&rsquo / s performance is tested for set point tracking, disturbance rejection and robustness issues using a simulation program. It is found that, the designed controller is performing satisfactorily, using the inferential control strategy for this complex reacting system.

In this study, the performance of the Model Predictive Controller (MPC) algorithm is investigated in two different reaction systems. The first case is a saponification reaction system where ethyl acetate reacts with sodium hydroxide to produce sodium acetate and ethanol in a CSTR. In the reactor, temperature and sodium acetate concentration are controlled by manipulating the flow rates of ethyl acetate and cooling water. The model of the reactor is developed considering first principal models. The experiments are done to obtain steady state data from the reaction system and these are compared with the model outputs to find the unknown parameters of the model. Then, the developed model is used for designing SISO and MIMO-MPC considering Singular Value Decomposition (SVD) technique for coupling. The second case is the reaction system used for the production of boric acid by the reaction of colemanite and sulfuric acid in four CSTR&rsquo / s connected in series. In the reactor, the boric acid concentration in the fourth reactor is controlled by manipulating the sulfuric acid flow rate fed to the reactor. The transfer functions of the process and disturbance (colemanite flow rate) are obtained experimentally by giving step changes to the manipulated variable and to the disturbance. A model-based and constrained SISO-MPC is designed utilizing linear step response coefficients. The designed controllers are tested for performance in set point tracking, disturbance rejection and robustness issues for the two case studies. It is found that, they are satisfactory except in robustness issues for disturbance rejection in boric acid system.

Zinc borate is a flame retardant additive used in polymers, wood applications and textile products. There are different types of zinc borate having different chemical composition and structure. In this study, the production of zinc borate that had the molecular formula of 2ZnO.3B2O3.3,5H2O was studied. The aim of this study was to investigate the effects of reaction parameters on the properties of zinc borate that had been synthesized by the reaction of boric acid and zinc oxide at the existence of the seed crystals and to determine the optimum experimental conditions for zinc borate production reaction. Reaction kinetics was also investigated to find a suitable kinetics model. The effect of boric acid to zinc oxide ratio -H3BO3:ZnO ratio- (3:1, 3.5:1, 5:1 and 7:1), the particle size of zinc oxide (10&micro / m and 25&micro / m), stirring rate (275 rpm, 400 rpm, 800 rpm and 1600 rpm), temperature (75&deg / , 85&deg / and 95&deg / ) and size of seed crystals (10&micro / m and smaller size) on reaction rate, reaction completion time, composition and particle size distribution of zinc borate were investigated. Experiments were performed in a continuously stirring, temperature controlled batch reactor with a volume of 1.5L. During the experiments samples were taken to be analyzed in regular time intervals. The analyses of the samples gave the concentration change of zinc oxide and boron oxide in the solid as well as the conversion of zinc oxide to zinc borate with respect to time and the rate of reaction was calculated. The products were also analyzed for particle size distribution. The experimental results showed that the reaction rate increased with the increasing H3BO3:ZnO ratio, particle size of zinc oxide, stirring rate and temperature. The reaction completion time was also decreased by increasing H3BO3:ZnO ratio, stirring rate and temperature. The particle size of final product, zinc borate, decreased with increasing stirring rate and size of zinc borate used as seed and increased with increasing particle size of zinc oxide used as reactant. The average particle sizes of the final product zinc borates synthesized at the end of the experiments were ranged between 4.3 &micro / m and 16.6 &micro / m. The zinc borate production reaction was mainly fitted the unreacted core model for the case of diffusion through product layer controls.

Thesis (doctoral)--Chalmers Tekniska högskola, 1972. / "Akademisk avhandling för filosofie doktorsexamen i kemi ... fredagen den 2 juni 1972 ... Chalmers tekniska högskola."

No description available.

Orientador: Salatiér Buzetti / Resumo: Os solos de Cerrado apresentam baixos teores de matéria orgânica e, sendo esta a principal fonte primária de boro (B), torna-se necessário o suprimento deste nutriente via adubação. Portanto, em plantios comerciais de eucalipto, é comum a adubação no sulco de plantio e até mesmo via foliar, durante a fase de implantação da cultura. Sendo assim, é importante verificar se a aplicação de B realizada inicialmente por meio de fontes com diferentes solubilidades é suficiente para atender as exigências da cultura ao longo do ciclo, ou se é necessária a reaplicação do elemento em cobertura. Objetivou-se com esse trabalho comparar o efeito residual das fontes de B aplicadas no sulco de plantio, assim como também a aplicação foliar e a reaplicação de B em cobertura na cultura do eucalipto (clone I144), tendo em vista o alto índice de bifurcação das árvores sem aplicação de B. O experimento foi conduzido na Fazenda Renascença, localizada no município de Três Lagoas/MS, com latitude 20o 34’ S e longitude 51o 50’ O e altitude de aproximadamente 305 m. O delineamento experimental foi blocos casualizados, com cinco repetições, em esquema fatorial, onde as parcelas foram subdivididas, perfazendo um 3 x 2 x 2, sendo o primeiro fator: 0 kg ha-1 de B; 1 kg ha-1 de B utilizando o fertilizante borogran (baixa solubilidade, 10% B), aplicado manualmente em filete contínuo no sulco de plantio; 1 kg ha-1 de B utilizando o fertilizante ácido bórico (alta solubilidade, 17% B), aplicado manualmente em f... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cerrado soils have low organic matter content, and this being the main primary source of boron (B), it is necessary to supply this element through fertilization. Therefore, in commercial eucalyptus plantations, it is common to fertilize in the planting groove and even via the foliar, during the implantation phase of the crop. Therefore, it is important to verify if the application of B carried out initially is sufficient to meet the crop requirements during the cycle, or if it is necessary to reapply the element under cover. The objective of this work was to compare the residual effect of the B sources applied to the planting groove, as well as the foliar application of the element and the reapplication of B in cover in the eucalyptus crop (clone I144), considering the high index of bifurcation in the treatments that did not receive the application of B. The experiment was conducted at Fazenda Renascença, located in the municipality of Três Lagoas/MS. The experimental design was randomized blocks, with five replications, in a factorial scheme, where the plots were subdivided, making a 3 x 2 x 2, being the first factor: 0 kg ha-1 of B; 1 kg ha-1 of B using borogran fertilizer (low solubility, 10% B), manually applied in continuous fillet in the planting groove; 1 kg ha-1 of B using boric acid fertilizer (high solubility, 17% B), manually applied in continuous fillet in the planting groove. Factorial 2 refers to the application or not of B via foliage. Two foliar applications o... (Complete abstract click electronic access below) / Doutor

Boric acid based fuel and oil additives were investigated in this study, with the aims to gain a deeper understanding of how the boric acid fuel additive behaves, to investigate the effect of low rates of fuel additive addition and tribofilm longevity, and to investigate how boric acid behaves as a hydraulic oil additive. Fuel additive experiments were performed in a reciprocating sliding rig with a cylinder on flat contact geometry with fuel additive sprayed on the contact repeatedly, whereas the hydraulic oil experiments were performed in a reciprocating sliding rig with a ball on flat contact with the oil and additive present from the start. Analysis was performed using vertical scanning interferometry (VSI), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). The tribofilms created by the fuel additive provided excellent friction reduction capabilities, even with low or no rate of replenishment. As more additive was sprayed, wear resistance seemed to increase as the surface became increasingly covered. Film coverage need to be less than 20% of the surface in order to gain full friction reducing effects. The hydraulic oil additive had little effect on friction or wear resistance under the used parameters and no tribofilm was found.

Submitted by Thiago de Souza Celestrino null (thiagocelestrino@yahoo.com.br) on 2018-02-15T23:10:09Z No. of bitstreams: 1 THIAGO DE SOUZA CELESTRINO_tese_corrigida-1.pdf: 1849166 bytes, checksum: db9e21bb2d41dddb2133285c68c4f044 (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-02-16T12:58:18Z (GMT) No. of bitstreams: 1 celestrino_ts_dr_ilha.pdf: 1957549 bytes, checksum: 4cf4e781aeff7c17a0ee39f00b69d05b (MD5) / Made available in DSpace on 2018-02-16T12:58:18Z (GMT). No. of bitstreams: 1 celestrino_ts_dr_ilha.pdf: 1957549 bytes, checksum: 4cf4e781aeff7c17a0ee39f00b69d05b (MD5) Previous issue date: 2017-12-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os solos de Cerrado apresentam baixos teores de matéria orgânica e, sendo esta a principal fonte primária de boro (B), torna-se necessário o suprimento deste nutriente via adubação. Portanto, em plantios comerciais de eucalipto, é comum a adubação no sulco de plantio e até mesmo via foliar, durante a fase de implantação da cultura. Sendo assim, é importante verificar se a aplicação de B realizada inicialmente por meio de fontes com diferentes solubilidades é suficiente para atender as exigências da cultura ao longo do ciclo, ou se é necessária a reaplicação do elemento em cobertura. Objetivou-se com esse trabalho comparar o efeito residual das fontes de B aplicadas no sulco de plantio, assim como também a aplicação foliar e a reaplicação de B em cobertura na cultura do eucalipto (clone I144), tendo em vista o alto índice de bifurcação das árvores sem aplicação de B. O experimento foi conduzido na Fazenda Renascença, localizada no município de Três Lagoas/MS, com latitude 20o 34’ S e longitude 51o 50’ O e altitude de aproximadamente 305 m. O delineamento experimental foi blocos casualizados, com cinco repetições, em esquema fatorial, onde as parcelas foram subdivididas, perfazendo um 3 x 2 x 2, sendo o primeiro fator: 0 kg ha-1 de B; 1 kg ha-1 de B utilizando o fertilizante borogran (baixa solubilidade, 10% B), aplicado manualmente em filete contínuo no sulco de plantio; 1 kg ha-1 de B utilizando o fertilizante ácido bórico (alta solubilidade, 17% B), aplicado manualmente em filete contínuo no sulco de plantio. O fatorial 2 se refere à aplicação ou não de B via foliar. Foram realizadas duas aplicações foliares de B até o primeiro ano de idade da cultura. Em cada aplicação foi utilizado ácido bórico a 0,5 % na calda com volume de 250 L ha-1. O último fator 2, se refere às subparcelas que receberam ou não a reaplicação de B aos 34 e 46 meses após o plantio, na projeção da copa, utilizando o fertilizante ácido bórico na dose de 1 kg ha-1 de B em cada aplicação. Para a aplicação de 1 kg ha-1 de B no plantio, há a necessidade da reaplicação do nutriente em cobertura, influenciando positivamente o seu teor no solo, no estado nutricional, produtividade de madeira, transferência de B ao solo e concentração no folhedo. As reaplicações de B também promoveram o maior acúmulo do nutriente no tronco, reduzindo, assim, a eficiência de uso do B na produção de madeira. Embora houve maior efeito residual de B no solo, em virtude da aplicação do borogran, as fontes de B se comportaram de modo semelhante para as mensurações de produtividade de madeira, concentração foliar, qualidade do fuste e transferência ao solo. Cabe destacar que, mesmo sendo uma dose considerada baixa (1 kg ha-1 de B), sua aplicação, bem como as aplicações foliares de B, reduziram a porcentagem de bifurcação das árvores. A densidade básica da madeira e o acúmulo de B nas frações (galhos e folhas) não foram influenciados pelo efeito residual das fontes de boro, assim como as aplicações foliares e reaplicações em cobertura. / Cerrado soils have low organic matter content, and this being the main primary source of boron (B), it is necessary to supply this element through fertilization. Therefore, in commercial eucalyptus plantations, it is common to fertilize in the planting groove and even via the foliar, during the implantation phase of the crop. Therefore, it is important to verify if the application of B carried out initially is sufficient to meet the crop requirements during the cycle, or if it is necessary to reapply the element under cover. The objective of this work was to compare the residual effect of the B sources applied to the planting groove, as well as the foliar application of the element and the reapplication of B in cover in the eucalyptus crop (clone I144), considering the high index of bifurcation in the treatments that did not receive the application of B. The experiment was conducted at Fazenda Renascença, located in the municipality of Três Lagoas/MS. The experimental design was randomized blocks, with five replications, in a factorial scheme, where the plots were subdivided, making a 3 x 2 x 2, being the first factor: 0 kg ha-1 of B; 1 kg ha-1 of B using borogran fertilizer (low solubility, 10% B), manually applied in continuous fillet in the planting groove; 1 kg ha-1 of B using boric acid fertilizer (high solubility, 17% B), manually applied in continuous fillet in the planting groove. Factorial 2 refers to the application or not of B via foliage. Two foliar applications of B were carried out until the first year of culture. In each application, 0,5% boric acid was used in the syrup with a volume of 250 L ha-1. The last factor 2, refers to the subplots that received or not the reapplication of B at 34 and 46 months after planting, in the crown projection, using the boric acid fertilizer at the dose of 1 kg ha-1 of B in each application. For the application of 1 kg ha-1 of B in the plantation, there is a need for reapplication of the covering element, positively influencing the soil element content, nutritional status of the crop, wood productivity, soil B transfer and soil concentration. element not leafed. The reapplications of B also promoted the greater accumulation of the element in the trunk of wood, thus reducing the efficiency of use of B in the production of wood. Although there was a greater residual effect of B in the soil due to borogran application, the sources of B behaved similarly to the measurements of wood productivity, leaf concentration, stem quality and soil transfer. It should be noted that even though a dose considered low (1 kg ha-1 of B), its application, as well as the foliar applications of B, reduced the percentage of bifurcation of the trees. There is a higher concentration of B in lower leaves of the crown when compared to the upper leaves, indicating, therefore, the low mobility of the element in the phloem. The basic wood density and the accumulation of B in the fractions (branches and leaves) were not influenced by the residual effect of the boron sources, as well as the foliar applications and reapplication of the cover element. / FAPESP: 14/03387-6

L'objectif de cette thèse est l'obtention de nouvelles données expérimentales en milieu acide borique dans le cadre du développement de modèles décrivant le comportement des produits de corrosion dans le circuit primaire, et notamment sur le relâchement du nickel par des phénomènes de dissolution/précipitation. Le travail présenté dans ce mémoire s'est focalisé sur une des phases solides du nickel, l'oxyde de nickel (NiO), ainsi que sur le comportement en solution de sa forme ionique, Ni2+. La solubilité de l'oxyde de nickel a été mesurée à haute température à l'aide d'un réacteur à circulation ouverte spécialement conçu pour fonctionner à haute température et haute pression. Compte tenu des concentrations très faibles en Ni dans les conditions de nos essais (300°C, pH>7, matrice bore-lithium), une méthode d'analyse du nickel dissous à l'échelle de l'ultra-trace (ng.kg-1) en milieu bore-lithium a été développée par ICP-MS et a été validée statistiquement par la méthode du profil d'exactitude. La complexation du nickel par les (poly)borates a ensuite été étudiée. Une expérience a été conduite où les ions nickel sont progressivement formés par oxydation d'une électrode de nickel métallique dans une solution d'acide borique. Basé sur les résultats expérimentaux et sur la modélisation de la spéciation aqueuse du bore, l'évolution du pH a montré l'existence significative d'un complexe nickel-bore. Le complexe neutre NiB3O4(OH)3 a été mis en évidence pour de fortes concentrations en acide borique, lorsque les polyborates sont présents. Les constantes d'équilibres ont été calculées à 25, 50 et 70°C, ainsi que les données thermodynamiques associées. Enfin, les cinétiques de dissolution de l'oxyde de nickel ont été mesurées en milieu acide chlorhydrique et en milieu acide borique de 25 à 100°C et un pH de 6. Les résultats ont mis en évidence un effet inhibiteur de l'acide borique sur les vitesses de dissolution de NiO dont le phénomène est exacerbé par l'augmentation de la température et de la concentration en bore. La formation d'un complexe surfacique a été mise en avant pour expliquer cet effet. / This work focuses on the nickel oxide phase (NiO) and the behavior in solution of its ionic form Ni2+. The solubility of nickel oxide has been determined at high temperature and pressure by the use of a flow through cell reactor specially designed to perform measurements in the conditions of the primary circuit. Because the solubility of nickel is very low at 300°C and pH>7, a new method for the determination of ultra-traces nickel concentrations in lithium/boron medium by ICP-MS coupled with a desolvator system nebulizer has been developed and validated by the statistical approach of accuracy profiles. The complexation of nickel by the (poly)borates has been also studied. Based on the experimental results and aqueous speciation modeling, the evolution of pH showed the existence of significant nickel-boron complexation. A neutral complex NiB3O4(OH)3 was postulated at high boric acid concentrations when polyborates are present, and the equilibrium constants were determined at 25, 50 and 70°C. The associated thermodynamics data have also been determined. Dissolution rates of nickel oxide have been measured in hydrochloric acid and in boric acid media up to 100°C and pH 6. Results showed that boric acid inhibits the dissolution rates of NiO and this phenomenon is enhanced by the temperature and the concentration of boron. The formation of a surface complex was postulated to explain this effect.