Дисертації з теми "Borinic acids"
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Bonnard, Mélanie. "Vitrimères boriniques : synthèses et applications." Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0051.
Vitrimers represent an innovative class of polymers introduced by Professor Leibler and colleagues in 2011. They define vitrimers as polymer networks capable of modifying their topology while maintaining a constant number of chemical bonds. These materials distinguish themselves by their ability to merge the characteristics of thermoplastics (reusability) and thermosets (superior thermomechanical properties and chemical resistance) through a chemical network incorporating dynamic covalent bonds. Exchange reactions such as boronic transesterification in vitrimers have been documented, highlighting the remarkable property of the B–O bond exchangeable without a catalyst. Although vitrimers containing boronic acid monomers have been developed, no publication has yet exposed the use of borinic acids in these materials. The synthesis of non-symmetric borinic acids is a complex task, however, their complexation with aminoalcohols allows their isolation in the form of aminoborinates, where the boron atom is stabilized by the lone pair of nitrogen electrons. These compounds could pave the way for vitrimers featuring an B–N bond more labile than the B–O bond in boronic acid esters. The main objective of this project is to design new functionalized borinic acid derivatives that can be used as monomers or crosslinking agents in vitrimers. This document describes the synthesis and utilization of non-symmetric borinates through a divergent strategy. These compounds were then employed in post-functionalization reactions such as 1,3-dipolar cycloaddition and Knoevenagel condensation. This aims to generate structures suitable for incorporation into copolymers to assess vitrimer formation
Chardon, Aurelien. "Acides boriniques et hydrosilanes : de la spécificité vers la réactivité." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC255.
Boron based Lewis acid such as borane, boronic and borinic acids, has recently emerged as a strong alternative to transition metal catalysts for catalysis. During Tharwat Mody El Dine thesis, a range of original borinic acids have been synthetized. These catalysts have been used to investigate catalytic peptides synthesis and amines formylation. This thesis work with aimed the association between borinic acids and hydrosilanes for organic synthesis. In the first part a borinic acid catalyzed amides reductions have been developed, our methodology work in mild conditions and displayed high chemoselectivities. In a second chapter, we will study the activity of borinic acids for the reduction of phosphine oxides, sulfoxides and amine N-oxide. After a study on the formation of previously observed amine-borane, a borinic acid mediated ketones, aldehydes and imines hydrosilylation have been demonstrated in the third chapter. In the fourth chapter a cooperative borinic acid-hydrosilane mediated amide bond formation has been developed, the mild conditions and the absence of racemization appear as the keys elements of this methodology. Finally, RMN and DFT instruments have been used to understand the relationship between structure and reactivity of borinic acids.All this study confirms the potential of borinic acids as efficient metal-free catalysts in many organic transformations.Mots clés : catalyse, acide borinique, hydrosilane, réduction, amides
Birepinte, Mélodie. "Amino(organo)boranes, synthèse et propriétés." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0231.
This manuscript presents the synthesis, reactivity and properties of amino(organo)boranes. The diisopropylaminoborane has been used for the formation of carbon-boron bonds. Its reactivity as a borylating agent was first explored for the hydroboration of alkynes catalyzed by Schwartz reageant. A large variety of alkenylaminoboranes, -boronates and -diazaborolanes was thus synthesized. Their stereoselective transformation into E and Z bromoalkenes was also optimized. The borylation of terminal alkynes via a tandem process of dehydrogenation/ dehydrogenative coupling allowed the access to a large scope of alkynylaminoboranes. Finally, the different reactivities of aminoboranes were used for the preparation of borinic acids bearing a phosphine group but also of a new class of chiral boron derivatives via a C-B atropisomerism. These chiral aminoarylboranes were fully characterized after separating the enantiomers and running spectroscopic analyses and racemization studies
Cree, Alistair Murray. "Fatigue in boric acid-sulphuric acid anodised aluminium alloys." Thesis, Open University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247058.
Dervisoglu, Ozgecan. "Inferential Control Of Boric Acid Production System." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12608766/index.pdf.
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.
Efhamisisi, Davood. "Preservation of plywood against biological attack with low environmental impact using tannin-boron preservative." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS235/document.
An experimental investigation was conducted to protect plywood panels made of perishable wood species (beech and poplar) against biological attacks with low environmental impact. The newly developed tannin-boron preservative which was proposed to reduce the leaching of borates was selected for this purpose. This system was used to protect plywood with two approaches: (1) in the glue line to replace formaldehyde based adhesives and gluing wood veneers, (2) pretreatment of wood veneers with the diluted formulations and bonded with melamine-urea-formaldehyde resin The research data in this thesis were obtained from three main groups of experiments: chemicals and thermomechanical testing on the tannin-boron resin, measuring physical and mechanical properties, and different biological tests before and after leaching processes. The chemicals testing on the tannin/hexamine adhesive showed that the addition ofboron, in the form of boric acid, can contribute more inter-flavonoid linkages and the opening of pyran rings which leads to the acceleration of polymerization reactions. Thermomechanical analysis on the adhesives of mimosa and quebracheo tannins confirmed that the addition of boric acid (1) lowered time and temperature of hardening, (2) and increased modulus of elasticity values of the adhesive. The addition of optimal boric acid into the tannin adhesive upgraded physical properties and tensile shear strength. An excess loading of boric acid (10%) in the glue line caused imperfect physical and mechanical features. Despite the low uptake of boric acid but its addition into the tannin glue provided effective resistance against fungal attack even after mild leaching test according to the EN 1250-2. The results of termites test showed that increase in the boric acid content of the adhesive caused the lower survival rate and the weight loss but samples underwent the high level of attack. No improvement against termite attack was obtained after leaching by a choice feeding test. The plywoods made of pretreated veneers by tannin-boron solutions showed partially lower tensile shear strength but still in the range of standards requirements for the humid applications. The satisfactory results were obtained even after severe leaching test against fungal attack with a strong polymeric network of tannin. The control plywoods made of pretreated veneers with boric acid alone solutions presented significant sensitivity against biological attack after leaching test. The results of termite tests showed the lower survival rate and the weight loss even after severe leaching test for the plywoods made of pretreated veneers with tannin-boron systems. The results of choice feeding test showed that termites preferred feeding from the controls when alternative samples were treated with the tannin-boron system. In general the evidence from this study suggests that tannin-boron system can significantly slow down the leaching of boron and it rendered high potential to preserve plywood
Zakharova, K., A. Mednikova, V. Rumyantsev, and T. Genusova. "Synthesis of Boron Carbide from Boric Acid and Carbon-Containing Precursors." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35601.
Yucel, Cakal Gaye O. "Dynamic Behavior Of Continuous Flow Stirred Slurry Reactors In Boric Acid Production." Phd thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605047/index.pdf.
s) in series system. In this reaction system there are at least three phases, one liquid and two solid phases (colemanite and gypsum). In a batch reactor all the phases have the same operating time (residence time), whereas in a continuous reactor all the phases may have different residence time distributions. The residence time of both the reactant and the product solids are very important because they affect the dissolution conversion of colemanite and the growth of gypsum crystals. The main aim of this study was to investigate the dynamic behavior of continuous flow stirred slurry reactors. By obtaining the residence time distribution of the solid and liquid components, the non-idealities in the reactors can be found. The experiments performed in the continuous flow stirred slurry reactors showed that the reactors to be used during the boric acid production experiments approached an ideal CSTR in the range of the stirring rate (500-750 rpm) studied. The steady state performance of the continuous flow stirred slurry reactors (CFSSR&rsquo
s) in series was also studied. During the studies, two colemanites having the same origin but different compositions and particle sizes were used. The boric acid production reaction consists of two simultaneous reactions, dissolution of colemanite and crystallization of gypsum. The dissolution of colemanite and the gypsum formation was followed from the boric acid and calcium ion concentrations, respectively. The effect of initial CaO/ SO42- molar ratio (1.00, 1.37 and 2.17) on the boric acid and calcium ion concentrations were searched. Also, at these initial molar ratios the colemanite feed rate was varied (5, 7.5, 10 and 15 g/min) to change the residence time of the slurry. Purity of the boric acid solution was examined in terms of the selected impurities, which were the magnesium and sulfate ion concentrations. The concentrations of them were compared at the initial molar ratios of 1.00 and 1.37 with varying colemanite feed rates. It was seen that at high initial CaO/ SO42- molar ratios the sulfate and magnesium ion concentrations decreased but the calcium ion concentration increased. The gypsum crystals formed in the reaction are in the shape of thin needles. These crystals, mixed with the insolubles coming from the mineral, are removed from the boric acid slurry by filtration. Filtration of gypsum crystals has an important role in boric acid production reaction because it affects the efficiency, purity and crystallization of boric acid. These crystals must grow to an appropriate size in the reactor. The growth process of gypsum crystals should be synchronized with the dissolution reaction. The effect of solid hold-up (0.04&ndash
0.09), defined as the volume of solid to the total volume, on the residence time of gypsum crystals was investigated and the change of the residence time (17-60 min) on the growth of the gypsum was searched. The residence time at each reactor was kept constant in each experiment as the volumes of the reactors were equal. The growth of gypsum was examined by a laser diffraction particle size analyzer and the volume weighted mean diameters of the gypsum crystals were obtained. The views of the crystals were taken under a light microscope. It was observed that the high residence time had a positive effect on the growth of gypsum crystals. The crystals had volume weighted mean diameters of even 240 µ
m. The gypsum crystal growth model was obtained by using the second order crystallization reaction rate equation. The residence time of the continuous reactors are used together with the gypsum growth model to simulate the continuous boric acid reactors with macrofluid and microfluid models. The selected residence times (20-240 min) were modeled for different number of CSTR&rsquo
s (1-8) and the PFR. The simulated models were, then verified with the experimental data. The experimentally found calcium ion concentrations checked with the concentrations found from the microfluid model. It was also calculated that the experimental data fitted the microfluid model with a deviation of 4-7%.
Ström, Simon. "Boric acid as a lubricating additive in fuels and in hydraulic oils." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-356795.
Marciasini, Ludovic. "Le diisopropylaminoborane : un agent de borylation alternatif pour la pformation de liaison carbone-bore. Etude de réactivité et développement de nouvelles méthodologies." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0216/document.
This manuscript describes the use of diisopropylaminoborane as borylating agent of aryl halides anddiazonium salts. This borylating agent has been the subject of studies in the laboratory and newmethodologies has been done. A general methodology of borylation of aryl diazonium salt catalyzed byiron, titanium and zirconium metallocene was developed, allowing access to useful compounds such ashalogenated aryl boron species. Furthermore, kinetic and mechanistic studies supported by theoreticalcalculation allowed a better understanding of the mechanism of the reaction. An extension of thepalladium catalyzed reaction was realized, allowing the use of aryl bromides and chlorides together witha new one-pot unsymetrical biaryl synthesis. Those methods allowed an efficient borylation of arylshalides using homogeneous semi-heterogeneous palladium catalyst. Finally, a study of reactivity of thediisopropylaminoborane and organometallics such as Grignard and organolithium was done. A generalmethodology was developed for the synthesis of diarylborinic acids and a mechanistic study wasachieved
Celestrino, Thiago de Souza. "Efeito residual e reaplicação de boro na cultura do eucalipto (Clone I144)." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/152742.
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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
Hu, Jinbo. "Associations tanins-bore pour des produits de protection du bois à faible impact environnemental." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS248/document.
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
Kavalcı, Sedat Akkurt Sedat. "The use of boron-containing additives for synthesis of anorthite ceramic powders/." [s.l.]: [s.n.], 2006. http://library.iyte.edu.tr/tezler/master/malzemebilimivemuh/T000561.pdf.
Keywords: Anorthite, boric acid, colemanite, statistical experimental design, X ray diffraction. Includes bibliographical references (leaves. 57-59).
Girka, Quentin. "Synthèse de dérivés furaniques à partir de biomasse et leur utilisation pour la synthèse de tensioactifs gemini." Thesis, Reims, 2015. http://www.theses.fr/2015REIMS016/document.
Due to stricter reglementations and the development of public opinion, surfactants synthesized from biomass are becoming increasingly interesting. However, the structural diversity of these compounds is still too low to compete with the products synthesized from fossil resources. In order to increase the diversity of available structures, we focused on common furanic building blocks, such as 2,5-diformylfuran (DFF), which are synthesized form carbohydrates. Firstly, we optimized a new and innovative synthesis of DFF. This method allowed us to use neither transition metal catalysts nor ionic liquids. The system we used to convert complex substrates, such as starch, relies on boric acid, sodium bromide and formic acid in dimethylsulfoxide (DMSO). Boric acid plays a key role in this system. It is involved in the biomass deconstruction, glucose to fructose isomerization and HMF formation. Sodium bromide in DMSO promotes the oxidation to DFF and formic acid increases the rate of this step. By using this system, we were able to synthesized DFF from glucose at multigram scale with 20% yield. After optimization of the synthesis, we investigated the oxidation mechanism. The second part of this work was focused on the conversion of DFF into new gemini surfactants. At the end of a five steps transformation, zwitterionic products were obtained with 50% yield. These gemini type compounds shows interesting properties such as very low critical micellar concentration which are similar to these measured for already reported gemini surfactants
Yendall, Keith A. "Optimisation of boric sulphuric acid anodising based processes for metal-to-metal adhesive bonding." Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/7575.
Erdogdu, Anil. "Dissolution Of Colemanite And Crystallization Of Gypsum During Boric Acid Production In A Batch Reactor." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605048/index.pdf.
3B2O3×
5H2O) in aqueous sulfuric acid whereby gypsum (CaSO4×
2H2O) is formed as a byproduct and must be separated from the main product. This process consists of two steps, dissolution of colemanite and formation of gypsum. The amount of boric acid formed depends on the first step, dissolution of colemanite. In the latter step, gypsum crystals are formed and stay in the reaction mixture to grow up to a size large enough to be filtered out of the solution. Filtration of gypsum crystals is a crucial process in boric acid production because it affects the purity and crystallization of boric acid. In this study it is aimed to investigate the effects of particle size of colemanite, stirring rate and reaction temperature on the dissolution of colemanite, gypsum formation and particle size distribution of gypsum formed in the reaction of boric acid production. Colemanite, sulfuric acid and distilled water were used as reactants for the boric acid production reaction in this study.The colemanite minerals were provided from a region of Emet, Kutahya, Turkey. Three types of colemanite minerals having different chemical composition and particle size were used. The sulfuric acid was supplied by Eti Holding A.S. Hisarcik 1 and Hisarcik 2 colemanites were crushed in a jaw crusher, ground in a hammer mill and then sieved. The sieve analysis was performed to learn the size distribution of Hisarcik 1 and Hisarcik 2 colemanite. Hisarcik 3 colemanite was brought from Emet Boric Acid Plant. The maximum diameter of the colemanite minerals was 150 &
#956
m. The experiments were performed at different particle sizes of colemanite (0-150, 0-250 and 250-1000 &
#956
m), temperatures (70- 90 &
#61616
C) and stirring rates (350-500 rpm). The photographs of gypsum crystals were taken. The boric acid and calcium ion concentrations were determined for each experiment. Also, the solid content of the solution in the reactor were measured. The dissolution of colemanite can be followed by monitoring the boric acid concentration change in the slurry. The crystallization of gypsum from the solution can be found from the calcium ion concentration in the solution. The crystallization kinetics of calcium sulfate dihydrate was studied. The growth of the gypsum crystals were examined under the light microscope and the particle size distribution of gypsum crystals were analyzed by of the laser diffraction instrument.
Simms, Nigel John. "The effect of boric acid on the high temperature oxidation of a 2.25Cr-1Mo steel." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292167.
Leung, James S. K. "Structural and functional studies of the xanthine transporter UapA and the boric acid transporter Bor1." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9679.
Johnsson, Elin. "Investigation of tribological mechanisms of a boron additive in lubricants and fuel enhancer." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-258234.
Olander, Petra. "Tribology for Greener Combustion Engines : Scuffing in Marine Engines and a Lubricating Boric Acid Fuel Additive." Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-333430.
Graff, Anaïs. "Solubilité et cinétique de réaction de l'oxyde de nickel dans les conditions du circuit primaire d'un réacteur à eau sous pression." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30254/document.
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
Henderson, Kimberly Ann. "Boric acid localization and effects on storage calcium release and the endoplasmic reticulum in prostate cancer cells." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1835448461&sid=11&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Ayittey, Foster Kofi. "Energy Efficient Process, Dynamic Modelling and Control of Boric Acid Promoted Potassium Carbonate Based CO2 Capture System." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/79402.
Примаченко, Сергій Володимирович, S. PRYMACHENKO, Н. Я. Круликівська та N. KRULYKIVSKA. "Вивчення ростових процесів пшениці м'якої (Triticum aestivum L.) на композиції бор-пектинових комплексів різної концентрації". Thesis, Біотехнологія: звершення та надії: збірник тез VII Міжнародної науково-практичної конференції НУБіП України (29-30 листопада 2018 року, м. Київ). - КОПРИНТ - 199 с, 2018. http://er.nau.edu.ua/handle/NAU/37475.
Perry, Richard. "Towards environmentally friendly electrodeposition : using citrate based electrolytes to deposit nickel and nickel-iron." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/16184.
Levonis, Stephan Michael. "Design and Synthesis of Boronolectin Fluorescence Sensors." Thesis, Griffith University, 2012. http://hdl.handle.net/10072/365998.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Institute for Glycomics
Science, Environment, Engineering and Technology
Full Text
Yan, Shicai. "Evaluation of Local Pathogenic Fungi, Boric Acid, and Their Potential Synergism for Control of the European Fire Ant, Myrmica Rubra (L.)." Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/YanS2005.pdf.
Asar, Isik. "Model Predictive Control (mpc) Performance For Controlling Reaction Systems." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605001/index.pdf.
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.
Karakurkchi, A. V., M. V. Ved, N. D. Sakhnenko, I. Yu Yermolenko, and S. I. Zyubanova. "Electroplating and functional properties of amorphous Fe-Mo(W) and Fe-Mo-W coatings." Thesis, Институт химии растворов им. Г. А. Крестова РАН, 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22618.
Mohamed, Fatheya. "Mineral analysis and proximate composition of leaves of (Brassica oleracea var. acephala) in response to boron application in pot experiments." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2793.
Choumollier (narrow-stem kale) (Brassica oleracea, L.) has been progressively used in recent years as a supplementary forage harvest in many countries with a temperate climate. Boron (B) and calcium (Ca) are the two most important elements for supporting plant structure and function of plasma membranes. Boron nutrition is vital for obtaining high quality yields in vegetables. The main objective of this study was to evaluate the extent to which boric acid concentration can affect growth parameters (plant height, leaf numbers, chlorophyll levels, and leaf size) of Brassica olereacea var. acephala at different stages of growth and development. Treatment comprised of four concentrations of boron (0.3 mg/kg, 0.4 mg/kg, 0.5 mg/kg and 0.6 mg/kg). Yield and physiological growth responses were measured during the course of the study to ascertain effectiveness and influence of boron treatments on the test crops. Leaves of B. oleracea were harvested at weekly intervals (W1, W2, W3, W4 and W5) after each treatment regimen for approximate basic mineral analysis and composition. Soil pH did not vary much among the various orchard blocks tested, regardless of soil depth. Exchangeable cations Na+ and K+ levels did not vary significantly, but Ca2+ and Mg2+ levels fluctuated considerably among orchards analyzed. The Control Orchard exhibited a higher P content than the other orchards. Ca, Mg, Cu and B levels did not vary significantly among the orchards, but Na, Fe and Zn levels were markedly raised in the Orchard treated with 0.3 mg/kg boron) relative to the Control Orchard. Chlorophyll fluorescence was significantly dependent on the treatment dose of boron as compared to control. Chlorophyll fluorescence also increased significantly with the growth period, i.e., the duration following the initial treatment at all doses of boron. Boron at all did not significantly affect leaf count, leaf length and plant height. The work may add to the body of knowledge on the influence of boron on the physiological performance, mineral contents and proximate composition of leaves of the species. Furthermore, the findings may have important applications in achieving high quality yields in vegetable crops.
Gurhan, Deniz. "Zinc Borate Production In A Batch Reactor." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12606996/index.pdf.
m and 25µ
m), stirring rate (275 rpm, 400 rpm, 800 rpm and 1600 rpm), temperature (75°
, 85°
and 95°
) and size of seed crystals (10µ
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 µ
m and 16.6 µ
m. The zinc borate production reaction was mainly fitted the unreacted core model for the case of diffusion through product layer controls.
Rinaldi, Luís Felipe. "Eficiência de uso de 15N-ureia tratada com inibidores de urease em associação com substâncias húmicas pela cultura do milho." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-28062018-155919/.
Urea (UR) is the most widely applied nitrogen (N) fertilizer in Brazilian agriculture. However, UR is more prone to ammonia (NH3) volatilization losses than other N sources when surface-applied. One alternative to improve nitrogen use efficiency (NUE) of surface-applied UR is through application of urease inhibitors as coating materials of UR. The association of these composts with humic substances (HS) as UR coating materials may also improve nutrient recovery by plants. The aim of this study was to evaluate the efficiency of urease inhibitors, associated or not with HS, as coating materials of UR as new top-dress N sources for maize. A greenhouse pot trial was carried out over 62 days with maize (Zea mays L.), in a completely randomized block design, with three replicates in a full factorial design, with UR coated with three urease inhibitors (0,40% B + 0,15% Cu; 0,64% B; NBPT) and one additional treatment without inhibitor, three doses of HS (0, 0.6, and 1.2%), and one control treatment. All treatments imposed had CO(15NH2)2 as N source, application rate of 180 mg kg-1of N, and side-dressing application at the V4 maize growth stage. Maize plants were assessed at V8 and VT growth stages, at 52 and 62 days after sowing, respectively, when it was evaluated: above and below-ground plant dry matter weight; leaf area; root morphological traits (length, surface area, and volume); and fertilizer use efficiency by the 15N balance method. In addition, semi-open static collectors with foam discs previously soaked in H3PO4- were used to quantify comparatively the NH3 volatilized from all treatments. Although the addition of a higher dose of boric acid on UR (0,64% B) promoted lower ammonia losses by volatilization in comparison to 0,40 % B + 0,15 % Cu, it did not result in higher NUE by maize in VT, which occurred at V8. In both growth stages, NBPT presented the best performance as urease inhibitor in the absence of HS. The application of HS did not increase NUE by maize in V8 and VT when associated with 0,40% B + 0,15% Cu, 0,64% B or even conventional UR. However, when added in conjunction with NBPT, it increased ammonia volatilization and reduced NUE in VT which may have occurred due to the high pH of the HS (8.5-9) and low buffering capacity. Moreover, the application of conventional UR or UR treated with HS and urease inhibitors did not increase maize growth rate or shoot/root dry matter weight in comparison to the control treatment at both growth stages. Likewise, there was no major significant differences between treatments on root morphological traits (length, surface area, and volume) at both growth stages assessed. The lack of sizable outcome differences between treatments could be explained by the application of a single N dose, the short period of time between the side-dressing application and assessment of maize plants, and to the surface-application of the HS and method of irrigation which prevented HS to have full contact with maize roots. Furthermore, HS application rate may have been too low to be effective.
Marangoni, Fernanda Forli. "Boro e zinco no sulco de plantio na cultura da cana-de-açúcar." Universidade do Oeste Paulista, 2016. http://bdtd.unoeste.br:8080/jspui/handle/jspui/1022.
Made available in DSpace on 2017-06-26T22:25:34Z (GMT). No. of bitstreams: 1 Fernanda Forli Marangoni.pdf: 1198622 bytes, checksum: 840bf0bfb09bc42c1ccdd37625bf6125 (MD5) Previous issue date: 2016-11-11
The determination of the appropriate levels of fertilization with micronutrients is essential for the culture to express its full productive potential, since they participate in vital functions in the metabolism of plants, participating in compounds responsible for metabolic and / or phenological processes. This research aims to evaluate the response of sugarcane (Saccharum officinalis) to fertilization with micronutrients (boron and zinc) in low fertility soils, in order to establish their adequate nutritional content. The experimental design was randomized blocks, in a factorial scheme (3 x 4) considering the application of three doses of boric acid (17% B) to provide 0, 1.0 and 2.0 kg ha-1 of boron and four doses Of zinc sulfate (20% Zn) for the supply of 2.0; 4.0 and 6.0 kg.ha-1 of zinc. The experimental area consisted, therefore, of three blocks with twelve experimental units, totaling 36 plots. In order to verify the results, the nutritional status of the plant (foliar diagnosis), soil analysis, indicators of technological quality and sugarcane production were analyzed. Through the evaluation of the results of the micronutrient contents foliar and in the soil it is noticed that there was no direct relation between the leaf contents of the sugarcane culture and different treatments applied during the conduction of the experiment. The technological attributes (Fibra, Brix, Pol and ATR) were not significantly influenced by the fertilization with boron and zinc. In cane-plant the highest yields were reached by application of 2.0 kg ha-1 of zinc represented by treatment 2, and in treatment 10, with a respective increase of 6% and 10%.
A determinação dos teores adequados de adubação com micronutrientes é fundamental para que a cultura possa expressar todo seu potencial produtivo, já que participam de funções vitais no metabolismo das plantas, participando de compostos responsáveis por processos metabólicos e/ou fenológicos. Esta pesquisa tem como objetivo avaliar a resposta da cana-de-açúcar (Saccharum officinalis) à adubação com micronutrientes (boro e zinco) em solos de baixa fertilidade, buscando estabelecer seus teores nutricionais adequados. O delineamento experimental foi blocos ao acaso, em esquema fatorial (3 x 4) considerando a aplicação de três doses de ácido bórico (17% B) visando fornecer 0, 1,0 e 2,0 kg ha-1 de boro e quatro doses de sulfato de zinco (20% Zn) para o fornecimento de 2,0; 4,0 e 6,0 kg.ha-1 de zinco. A área experimental constava, portanto, de três blocos com doze unidades experimentais, totalizando 36 parcelas. Para a verificação dos resultados foi analisado o estado nutricional da planta (diagnose foliar), a análises de solo, os indicadores de qualidade tecnológica e de produção da cana-de-açúcar. Através da avaliação dos resultados dos teores de micronutriente foliares e no solo nota-se que não houve relação direta entre os teores foliares da cultura da cana-de-açúcar e diferentes tratamentos aplicados durante a condução do experimento. Os atributos tecnológicos (Fibra, Brix, Pol e ATR) não foram influenciados significativamente pela adubação com boro e zinco. Em cana-planta as maiores produtividades foram atingidas pela aplicação de 2,0 kg ha-1 de zinco representado pelo tratamento 2, e no tratamento 10, com aumento respectivo de 6% e 10%.
Pieck, Dario. "Optilmisation de l'utilisation du gadolinium comme poison consommable dans le combustible nucléaire : Vers une REP sans bore." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4064.
Reactivity excess in Nuclear Power Plants is controlled by reactor’s active systems: boric acid dilution and control rods. Alternatively, negative reactivity insertion can be made in a passive way using burnable poisons, i.e. neutron absorbers, this is the case of gadolinium (Gd).In the industrial framework of U²³⁵ enrichment increase and boric acid restraint, the goal of this thesis is to optimize the distribution of gadolinium in UO₂ ceramics to obtain a high-performance provision of negative reactivity in Pressurized Water Reactors.In this sense, the work is focus on new gadolinium-rich materials. Thus, U-Gd-O phase diagram was explored in the field of high Gd contents. Two cubic phases were found and characterized: the C1 and C2 phases. With the aim of an industrial application, C1 phase was selected as candidate for Gd addition into UO₂ pellets.The optimal distribution of C1 phase within a nuclear fuel assembly was studied using APOLLO 2.8 neutron transport code. Parametrical calculations were performed. These neutronic studies have ends in a successful “concept of poisoned pellet”.Finally, some prototype pellets following this concept were made in laboratory to proof it feasibility.All the obtained results shows that the proposed concept of a neutrophage C1-phase coating on UO₂ pellets is a convenient way to reduce reactivity excess within the framework of long irradiation cycles. This concept could be potentially applied in industrial scale. Consequently a patent application process was initiated
Granja, Ana Carolina Ribeiro. "Separação dos isótopos estáveis de boro, por troca iônica em sistema cascata, e obtenção de H310BO3 enriquecido em 10B." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-17012014-113125/.
The chromatographic method of ion exchange resin in columns was used to study the isotopic enrichment of 10B and H3 10BO3. In two column chromatographic systems (S1: six acrylic columns 1800 mm length and 70 mm diameter; S2: six acrylic columns 1800 mm length and 30 mm diameter) was studied 10B isotope separation in equilibrium involving aqueous boric acid and borate ions adsorbed on anionic resin of the quaternary ammonium type (Dowex 1X8) 100-200 \"mesh\". The production systems H3 10BO3 were evaluated individually and in cascade process with 10B transfer between both systems. The measurements of B in this study were evaluated by Inductively Coupled Plasma Mass Spectrometry and Thermal Ionization Mass Spectrometry. In the S1 columns system displacement after 243 m (135 DBC) was possible obtain an medium enrichment in the last 20 cm, of 40 % atoms 10B, corresponding to 2830 mg of H310BO3. This mass was transferred to the S2 column system which have introduced in the last 20 cm of the band medium enrichment of 47,8 atom% 10B and this new band chromatography was displaced 21,6 m, thus obtaining the last centimeter band (1-0 cm) from enriched fraction 82 % atoms 10B. The fractionation factor (\'alfa\') and the Height Equivalent of Theoretical Plate (HETP) of stable isotopes of B (10B and 11B) was determined like being 1,0245 and 0,30 cm, respectively
Folco, Jardel Castro. "Análise de corrosão por espectroscopia de impedância em bronzinas de motores a combustão flexíveis." reponame:Repositório Institucional da UFABC, 2014.
Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2014.
Motores a combustão flexíveis foram desenvolvidos para diversificar a utilização de combustíveis para a indústria da mobilidade, com o intuito de trazer benefícios econômicos, ganho em sustentabilidade e redução do impacto ambiental. Tal diversificação tem proporcionado o desenvolvimento de linhas de pesquisa que aperfeiçoem essa utilização, através de incentivo fiscal do governo, bem como injeção de recursos da indústria nas universidades como, por exemplo, o programa Inovar Auto. Dentre os novos combustíveis está o etanol que devido às suas características físico-químicas, como a sua pressão de vapor traz vantagens como ganho de torque e potência e desvantagens como aumento de desgaste e corrosão dos componentes metálicos a ele expostos. As bronzinas são partes de base metálica que promovem a redução do contato metal-metal entre as principais peças de um motor como bloco, virabrequim e biela, além de permitirem uma melhor hidrodinâmica do óleo lubrificante, aumentando a vida útil do motor. Significativamente expostas ao ambiente etanol, óleo, gases e água, as mesmas são suscetíveis ao fenômeno de corrosão. Análise de corrosão por espectroscopia de impedância eletroquímica é um método conhecido na literatura e motivou a caracterização eletroquímica de componentes cíclicos metálicos de motores, através da obtenção de espectros de impedância para três diferentes recobrimentos em bronzinas, expostos sistematicamente a condicionamentos e envelhecimentos, variando-se temperatura, tempo de exposição em mistura óleo e etanol comuns. Dentre os três recobrimentos está uma proposta cerâmica a partir de óxido de boro depositado por uma técnica comum denominada slurry, apresentada na literatura aeroespacial com vantagens tribológicas. As medições foram feitas em solução aquosa de cloreto de sódio a 0,1 M, utlizando-se um eletrodo de referência de prata e cloreto de prata, um eletrodo de medição de platina como contra eletrodo e um eletrodo de trabalho com amostras de aço embutidas e recobertas com três diferentes superfícies; metálica (VW1), polimérica (P1) e cerâmica (C1), dispostos em uma célula ligada a um impedancímetro e a um potenciostato de marca Solartron. A intersecção do semicírculo do espectro com o eixo das abcissas ou parte real da impedância, Z¿ é conhecida como resistência de polarização Rp. Da literatura sabe-se que esta grandeza é proporcional ao inverso da corrente e taxa de corrosão da superfície do eletrodo de trabalho. A obtenção desta variável pode ser feita através de aproximações, com modelos de circuitos equivalentes RC, que calculam as resistências e capacitâncias destes circuitos. A partir do tratamento dos dados acima descritos, foi possível estabelecer três diferentes tendências de comportamento da taxa de corrosão ao longo do tempo de exposição ao meio etanol mais óleo, a saber: amostra de superfície metálica tipo VW1 apresentou corrosão dinâmica e controlada com taxa de corrosão decrescente ao longo do tempo; amostra polimérica tipo P1 apresentou também redução da taxa de corrosão por passivação ao longo do tempo após penetração da camada polimérica e; amostra cerâmica de óxido de boro tipo C1 apresentou maior redução da taxa de corrosão ao longo do envelhecimento em óleo e etanol.
Flex fuel combustion engines were developed to diversify the use of fuels for the mobility industry, in order to bring economic benefits gain in sustainability and environment impact reduction. Such diversification has permitted the research line development which optimizes this use through government incentive as well as fund injection in universities such as Inovar Auto program. Ethanol is among the new fuels, which due to its physical-chemical characteristics (vapor pressure) presents advantages as power and torque and disadvantages, as waste increase and corrosion of the exposed metal components. The bearings are parts made of metal that promote the metal-metal contact reduction among the main engine parts like cylinder block, cranckshaft and connecting rods. Besides, they allow better hydrodynamics of the lubrication oil increasing the duration of a flex combustion engine. Exposed to the ethanol, oil, gases and water environment these bearings are prone to corrosion phenomenon. The corrosion analysis by impedance spectroscopy corrosion is a method known in the literature and has motivated the electrochemical characterization of metal cyclic components by obtaining impedance spectra for three different recovering in bearings. The third type of recovering was developed through bore oxide produced by slurry coating techniques, which was presented on a aerospacial research publication with tribologic gain. These are systematically exposed to conditionings and aging while varying temperature, exposure time and rotation of oil and ethanol common mixtures. The measurements were made on aquous solution of NaCl 0,1 M through a reference silver and silver cloride eletrode, a platine counter eletrode and the work eletrode with samples of the three different bearings surface, metallic (VW1), polymeric (P1) and ceramic (C1) all assembled in a eletrochemistry cell, switched to a potenciostat and an impedancimeter, both by Solartron. The intersection of the semicircle spectra with "X" axle or real part of the impedance Z¿ is known as polarization resistance Rp. From the bibliography review it is known that this resistance is proportional to the inverse of corrosion rate on the surface of the working electrodes. The obtention of this variable could be done through approximation of RC circuit models, which calculate the resistances and the capacitances. Through data treatment it was possible to establish three different tendencies of corrosion rate behavior during ethanol and oil exposure time: Metallic surface sample type VW1 presented dynamic controlled with descending corrosion rate during the aging processes. Polymeric recovery sample type P1 also presented reduction of corrosion rate after penetration of the polymeric recovering e less during the aging processes. Ceramic recovery sample type C1 presented major reduction of corrosion during the aging on oil plus ethanol.
Saleem, Saima. "A method of chemical aftertreatment for the reduction of free formaldehyde release of a durable flame retardant finished cotton fabric." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-360.
Hýža, Bohumil. "Možnost zpracování glycerolové fáze z výroby bionafty." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217043.
Hýža, Bohumil. "Možnosti zpracování odpadů glykolu a glycerolu na účelové látky." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217075.
Nakath, Richard. "Sieden in Anwesenheit von Borverbindungen in Leichtwasserreaktoren." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-154457.
Rocha, Gilson Silvério da. "Modelos lineares mistos para dados longitudinais em ensaio fatorial com tratamento adicional." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11134/tde-14122015-174119/.
Assays aimed at studying some crops through multiple measurements performed in the same sample unit along time, space, depth etc. have been frequently adopted in agronomical experiments. This type of measurement originates a dataset named longitudinal data, in which the use of statistical procedures capable of identifying possible standards of variation and correlation among measurements has great importance. The possibility of including random effects and modeling of covariance structures makes the methodology of mixed linear models one of the most appropriate tools to perform this type of analysis. However, despite of all theoretical and computational development, the use of such methodology in more complex designs involving longitudinal data and additional treatments, such as those used in forage crops, still needs to be studied. The present work covered the use of the Hasse diagram and the top-down strategy in the building of mixed linear models for the study of successive cuts from an experiment involving boron fertilization in alfalfa (Medicago sativa L.) carried out in the field area of Embrapa Southeast Livestock. First, we considered a qualitative approach for all study factors and we chose the Hasse diagram building due to the model complexity. The inclusion of random effects and selection of covariance structures for residues were performed based on the likelihood ratio test, calculated based on parameters estimated through the restricted maximum likelihood method, the Akaike\'s Information Criterion (AIC), the Akaike\'s information criterion corrected (AICc) and the Bayesian Information Criterion (BIC). The fixed effects were analyzed through the Wald-F test and we performed a regression study due to the significant effects of the variation sources associated with the longitudinal factor. The Hasse diagram building was essential for understanding and symbolic displaying regarding the relation among all factors present in the study, thus allowing variation sources and their degrees of freedom to be decomposed, assuring that all tests were correctly performed. The inclusion of random effect associated with the sample unit was essential for modeling the behavior of each unity. Furthermore, the structure of variance components with heterogeneity, added to the residues, was capable of modeling efficiently the heterogeneity of variances present in the different cuts of alfalfa plants. The fit was checked by residual diagnostic plots. The regression study allowed us to evaluate the productivity of shoot dry matter (kg ha-1) related to successive cuts of alfalfa plants, involving the comparison of fertilization with different boron sources and doses. We observed the best productivity in the combination of the source ulexite with the doses 3, 6 and 9 kg ha-1 boron.
Zouzou, Michel. "Contribution à l'étude de quelques effets de l'acide borique in situ (Coleoptile de blé, hypocotyle de tournesol; Comparaison avec les acides phenylacétique et indolyl-3 acétique) et in vivo (développement de la plantule de tournesol; Croissance." Besançon, 1988. http://www.theses.fr/1988BESA2035.
Ošťádal, Michal. "Návrh čerpadla a potrubní trasy pro zajištění vyšší bezpečnosti jaderné elektrárny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443200.
El, Yamani Mohamed Saad Eddine. "Corrosion sous contrainte des aciers inoxydables austenitiques dans les milieux boriques chlorures : etude electrochimique et analytique des films passifs." Paris 6, 1988. http://www.theses.fr/1988PA066226.
Williamson, Caitlin. "Borinic Acid-catalyzed Regioselective Functionalization of Polyols." Thesis, 2011. http://hdl.handle.net/1807/31637.
Zhuang, Cheng-Ming, and 莊承銘. "Spectroscopic and theoretical investigations of complexes of aluminum ion and boric acid with aromatic organic acids." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/48308137221632110636.
國立中興大學
土壤環境科學系所
99
Natural organic matters (NOM) are the common materials found in environment, where they play an important role in many reactions due to the containing of functional groups like carboxylic and catechol groups. The chelated interactions of metals with NOM in the environment are critically dependent upon both the ligand properties of the NOM and the character of the metals. It is important to predict and investigate the mechanism of aluminum and boric acid complexes with some well-known ligands. The aim of the present work was to investigate the ligands reactivity and confirm the chelated sites at the aromatic organic acids to Al3+ and B(OH)3. We studied the electronic spectrums of organic complexes with Al3+ and boric acid in methanol solution, and we recorded the results of the intensity of band shift increases gradually. To obtain the chelated mechanism and explain the reaction pathways, we calculated the possible complexes involving the carboxylic and catechol groups by Gaussian03 at the B3LYP/6-31G method in IEFPCM/Methanol model. We can observe the changes of the structures, charges, energies, and molecular orbitals from the theoretical calculation of complexes with different ligands at aromatic organic acids. Compared with both the results from theoretical calculations and experiments, the reaction pathway is indicated that the Al3+ for catechol group and B(OH)3 for carboxylic group are favored. It`s also correspond to the results from time-dependent DFT (TD-DFT) with experiments for Al3+ and boric acid. Theoretical calculation can observe the influence of different ligands to structure from aromatic organic acids, and it also proved the chelated pathways and mechanism of Al3+ and B(OH)3 with the aromatic organic acids.
陳明煌. "The study of developer without boric acid for bump application." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/wkyj5y.
國立高雄大學
化學工程及材料工程學系碩士班
104
In this research, a novel type of non-boron developer was developed for improving the properties of the conventional boron developer applied in bumping process. First, the properties of three kinds of the conventional developers applied in bumping process were compared. Then, the amount of inorganic salt, i.e., alkali-salt and buffer, of MIB developers could be identified using the value R of titration curve. Development rate of the developer increases as the inorganic alkali-salt increases; the function of buffer could be reduces the pH value rapid decline in the development process. Breaking time and end point of the developer including various buffers were also studied. Finally, non-boron developer was compared with the conventional developer. It can be seen that the developed photoresist profile either optical microscope or the cross section of SEM image were almost the same. Micro-etching of non-boron developer for various metals, e.g., copper and titanium-tungsten alloy, were not that obviously. For the aluminum, the micro-etching decreased progressively with increasing buffer content. Non-boron developer via the modified buffer salt could replace the conventional boron developer, and further improvement of the environment.
Wang, Wei-chung, and 王維中. "Preparation Trimethyl Borate via Esterification Reaction of Boric Acid with Methanol." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/46316690087843072758.
國立成功大學
化學工程學系碩博士班
97
In this work, regeneration of sodium metaborate, one of the main products from hydrolysis of sodium borohydride for generation of ultrapure hydrogen, back to trimethyl borate (TMB), a precursor to sodium borohydride, was studied. The regeneration strategy mainly composed of two stages: one from sodium metaborate to boric acid, and the other from borica cid to trimethyl borate via esterification. X-ray diffractometer (XRD) revealed successful conversion from sodium metaborate, reaction with sulfuric acid, to boric acid. The average conversion rate is about 55%, based on sodium metaborate used. Gas chromatographers (GC) equipped either with flame ionization detector (FID) or Mass Spectrophotometer (MS) were used to determine quantitatively and qualitatively the esterification of boric acid and methanol to yield trimethyl borate. Interestingly, not TMB but also other borane chemicals appeared in the products of the esterification, as revealed by GC-MS. In order to purify the TMB, three-stage distillation was employed. As a result, the yield in average from boric acid to trimethy borate is circa 90%. That is, the total conversion efficiency from sodium metaborate to trimethyl borate near 50%. could be achieved.
Huang, Kuan-Chieh, and 黃冠傑. "A Study on Trivalent Chromium Sealing Procedure in Boric Acid - Sulfuric Acid Anodizing Process for Aluminum Alloys." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5159032%22.&searchmode=basic.
國立中興大學
材料科學與工程學系所
107
Due to its low density, high strength and workability, aluminum alloys are widely used in the aeronautic industry and served as the main composition of aircrafts which usage can reach more than 60% generally. However, there are still some negative shortages for aluminum alloys which existed the risk for using, such as the low hardness, poor wear resistance, and can generate to dissimilar metal corrosion while it contacts with different alloys. In order to solve the problems, particular surface treatments shall be done to improve the mechanical properties, and anodizing is the most common process. In general, aluminum alloy can form oxide layers itself under the normal environment. However, the thickness of oxide layer is too thin and there are no practical benefits. The porous nanostructure formed by the anodizing treatment can increase the adhesion of the subsequent organic coating and corrosion resistance. Chromic acid anodizing and sulfuric acid anodizing are the most common anodizing treatments. The oxide layer produced by chromic acid anodizing is dense and thin, the corrosion resistance is also excellent due to the self-healing of hexavalent chromium, However, with the trend of environment friendly, chromium is prohibited since its high carcinogenic and toxic. Though sulfuric acid anodizing will not lead to the pollution, it will degrease alloys fatigue properties since its hardness of oxide layer. To solve these negative properties, boric acid sulfuric acid anodizing is developed in recent years as the alternatives. To increase the corrosion resistance of anodizing layer, sealing process is applied to seal the porous layer of anodizing to the non-absorptive surface, it''s also make anodizing surface be able to pass the high corrosion requirements of aerospace industry. Currently, dilute chromium sealing and sodium dichromate sealing are both applied on boric acid sulfuric acid anodizing. However, both processes exist the risk for prohibition since the usage of hexavalent chromium. On the other hand, there are also some environment friendly sealing processes like hot water sealing or vapor sealing. But these processes need to be treated at high temperature, it''s not common used due to it high energy consumption and high waste. In order to solve the high energy consumption caused from water sealing and toxic materials disposition caused from hexavalent chromium, trivalent chromium sealing is then developed actively. In this paper, trivalent chromium sealing process with boric acid sulfuric acid anodizing is discussed to verify if it can satisfy the requirements of corrosion resistance and paint adhesion of aerospace industry. Microstructural differences between hexavalent chromium sealing and trivalent chromium sealing are also compared through SEM and EDX. Trivalent chromium sealing is then evaluated as the replacement of hexavalent chromium sealing.
Chia-HsunLiu and 劉佳勳. "Boron Recovery from Boric Acid Wastewater by Chemical Oxo-Precipitation (COP) Technology." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/32316200508327184248.
國立成功大學
化學工程學系碩博士班
101
This study investigated a chemical oxo-preceipitation (COP) process for the treatment of the synthetic boric acid wastewater. COP combined the oxidant treatment and chemical precipitation using different metal salts (CaCl2 and BaCl2) for boron removal. Metal borate which was of high purity and single compound could be recovered by fluidized-bed homogeneuous Granulation (FBHG) process without adding seed materials. In COP stage, the molar ratio of metal to boron (Me/B), H2O2 to boron (H2O2/B) and pH were the primary variables for optimizing the treatment of 1000 mg-B/L synthetic boric acid solution. At pH around 10-11, the boric acid concentration could be substantially redued to 129 and 38 mg-B/L using CaCl2 and BaCl2 as precipitants, respectively, through the COP conditions of H2O2/B=1 and Me/B=1. Besides, H2O2 dosage affected the COP efficiency on boron removal more than precipitant did. In FBHG stage, the optimal parameters (U=20 m/hr、H2O2/B=1.5、Ba/B=2、pHe=9) could successfully recover the spherical particles of barium peroxoborate. For a feed level of 300 mg-B/L, 60% of crystallization ratio and 85% of removal efficiency were obtained at pH 10.75. The particles from FBHG were characterized by SEM, XRD, Raman, and thermal analysis (TGA and DSC). The peroxide (O-O) functional group in particles could be monitored by Raman spectroscopy. The XRD patterns indicate that the FBHG products had a poor crystallinity; however, these borate compounds showed clear characteristic peaks that were well fitted with calcium metaborate (CaB2O4) and barium metaorate (BaB2O4) phase after 700 °C calcination. Water evaporation and oxygen released during the thermal decomposition could be observed through TGA and DSC analysis. According to the analytical results, the FBHG products using calcium ion and barium ion as precipitants were supposed to be calcium peroxoborate (Ca(BO3)2 • nH2O) and barium peroxoborate (BaB2O4(OH)4), respectively.