The modeling of the soft-output decoding of a binary linear block code using a Binary Phase Shift Keying (BPSK) modulation system (with reduced noise power) is the main focus of this work. With this model, it is possible to provide bit error performance approximations to help in the evaluation of the performance of binary linear block codes. As well, the model can be used in the design of communications systems which require knowledge of the characteristics of the channel, such as combined source-channel coding. Assuming an Additive White Gaussian Noise channel model, soft-output Log Likelihood Ratio (LLR) values are modeled to be Gaussian distributed. The bit error performance for a binary linear code over an AWGN channel can then be approximated using the Q-function that is used for BPSK systems. Simulation results are presented which show that the actual bit error performance of the code is very well approximated by the LLR approximation, especially for low signal-to-noise ratios (SNR). A new measure of the coding gain achievable through the use of a code is introduced by comparing the LLR variance to that of an equivalently scaled BPSK system. Furthermore, arguments are presented which show that the approximation requires fewer samples than conventional simulation methods to obtain the same confidence in the bit error probability value. This translates into fewer computations and therefore, less time is needed to obtain performance results. Other work was completed that uses a discrete Fourier Transform technique to calculate the weight distribution of a linear code. The weight distribution of a code is defined by the number of codewords which have a certain number of ones in the codewords. For codeword lengths of small to moderate size, this method is faster and provides an easily implementable and methodical approach over other methods. This technique has the added advantage over other techniques of being able to methodically calculate the number of codewords of a particular Hamming weight instead of calculating the entire weight distribution of the code.

The microstructure of polyolefins determines their macroscopic properties. Consequently, it is essential to predict how polymerization conditions will affect polyolefin microstructure. The most important microstructural distributions of ethylene/alfa-olefin copolymers made with coordination catalysts are their molecular weight (MWD), chemical composition (CCD), and comonomer sequence length (CSLD). Several mathematical models have been developed to predict these microstructural distributions; reliable techniques to estimate parameters for these models, however, are still poorly developed, especially for catalysts that have multiple site types, such as heterogeneous Ziegler-Natta complexes. Most commercial polyolefins are made with heterogeneous Ziegler-Natta catalysts, which make polyolefins with broad MWD, CCD, and CSLD. This behavior is attributed to the presence of several active site types, leading to a final product that can be seen as a blend of polymers made on the different catalyst site types. The main objective of this project is to develop a methodology to estimate the most important parameters needed to describe the microstructure of ethylene/alfa-olefin copolymers made with these multiple site-type catalysts. To accomplish this objective, we developed the Integrated Deconvolution Estimation Model (IDEM). IDEM estimates ethylene/alf-olefin reactivity ratios for each site type in two-steps. In the first step, the copolymer MWD, measured by high-temperature gel permeation chromatography, is deconvoluted into several Flory’s most probable distributions to determine the number of site types and the weight fractions of copolymer made on each of them. In the second estimation step, the model uses the MWD deconvolution information to fit the copolymer triad distributions measured by 13C NMR and estimate the reactivity ratios per site type. This is the first time that MWD and triad distribution information is integrated to estimate the reactivity ratio per site type of multiple site-type catalysts used to make ethylene/alfa-olefin copolymers. IDEM was applied to two sets of ethylene-co-1-butene copolymers made with a commercial Ziegler-Natta catalyst, covering a wide range of 1-butene fractions. In the first set of samples (EBH), hydrogen was used as a chain transfer agent, whereas it was absent in the second set (EB). Comparison of the reactivity ratio estimates for the sets of samples permitted the quantification of the hydrogen effect on the reactivity ratios of the different site types present in the Ziegler-Natta catalyst used in this thesis. Since 13C NMR it is an essential analytical step in IDEM, triad distributions for the EB and EBH copolymers were measured in two different laboratories (Department of Chemistry at the University of Waterloo, and Dow Chemical Research Center at Freeport, Texas). IDEM was applied to both set of triad measurements to find out the effect of interlaboratory 13C NMR analysis on reactivity ratio estimation.

The microstructure of polyolefins determines their macroscopic properties. Consequently, it is essential to predict how polymerization conditions will affect polyolefin microstructure. The most important microstructural distributions of ethylene/alfa-olefin copolymers made with coordination catalysts are their molecular weight (MWD), chemical composition (CCD), and comonomer sequence length (CSLD). Several mathematical models have been developed to predict these microstructural distributions; reliable techniques to estimate parameters for these models, however, are still poorly developed, especially for catalysts that have multiple site types, such as heterogeneous Ziegler-Natta complexes. Most commercial polyolefins are made with heterogeneous Ziegler-Natta catalysts, which make polyolefins with broad MWD, CCD, and CSLD. This behavior is attributed to the presence of several active site types, leading to a final product that can be seen as a blend of polymers made on the different catalyst site types. The main objective of this project is to develop a methodology to estimate the most important parameters needed to describe the microstructure of ethylene/alfa-olefin copolymers made with these multiple site-type catalysts. To accomplish this objective, we developed the Integrated Deconvolution Estimation Model (IDEM). IDEM estimates ethylene/alf-olefin reactivity ratios for each site type in two-steps. In the first step, the copolymer MWD, measured by high-temperature gel permeation chromatography, is deconvoluted into several Flory’s most probable distributions to determine the number of site types and the weight fractions of copolymer made on each of them. In the second estimation step, the model uses the MWD deconvolution information to fit the copolymer triad distributions measured by 13C NMR and estimate the reactivity ratios per site type. This is the first time that MWD and triad distribution information is integrated to estimate the reactivity ratio per site type of multiple site-type catalysts used to make ethylene/alfa-olefin copolymers. IDEM was applied to two sets of ethylene-co-1-butene copolymers made with a commercial Ziegler-Natta catalyst, covering a wide range of 1-butene fractions. In the first set of samples (EBH), hydrogen was used as a chain transfer agent, whereas it was absent in the second set (EB). Comparison of the reactivity ratio estimates for the sets of samples permitted the quantification of the hydrogen effect on the reactivity ratios of the different site types present in the Ziegler-Natta catalyst used in this thesis. Since 13C NMR it is an essential analytical step in IDEM, triad distributions for the EB and EBH copolymers were measured in two different laboratories (Department of Chemistry at the University of Waterloo, and Dow Chemical Research Center at Freeport, Texas). IDEM was applied to both set of triad measurements to find out the effect of interlaboratory 13C NMR analysis on reactivity ratio estimation.

Doctor of Philosophy / Department of Grain Science and Industry / Finlay I. MacRitchie / Novel genetic materials were used to deduce gluten protein composition-functionality relationships. The Pegaso bread wheat near-isogenic lines (NILs) included addition, variation and/or deletion of major loci coding for HMW-GS, LMW-GS and gliadins. The waxy wheat lines (Svevo and N11 set) included wild, partial and complete waxy lines. Triticale translocations include 1R.1D and 1A.1D lines (GDS7, Trim, Rhino and Rigel sets) with HMW-GS 5+10 and 2+12. The main goal of the study was to establish the usefulness of NILs as appropriate materials to investigate the structure-function relationships of wheat proteins and to evaluate the performance of unique triticale translocations and waxy wheat lines. Effect of genetic variation on phytochemical (phenolic acid and policosanol) contents was also studied. Innovative methods like MALLS, Lab-on-a-chip and micro (10 g) baking were utilized along with traditional analytical methods. Results confirmed the potential of using NILs in understanding the effects of certain proteins coded at specific loci that might often be targeted in breeding programs. Removal of expected chain terminators at Gli-1/Gli-2 loci causes a shift in MWD to higher values, reflected in higher UPP and dough strength. Lines with HMW-GS 5+10 were clearly separated from 2+12 lines in terms of dough strength and UPP. The present study obtained evidence that modified ω-gliadins acts as chain terminators and cause reduction of protein polymer size and thus shifts in MWD. Marked differences in terms of milling characteristics, protein composition and ultimately in end-use functionality were observed with various waxy wheat null lines. Loaf volumes with waxy wheat flour alone were higher than a 50% blend with commercial wheat; however, breads were unacceptable to consumers in all aspects. Poor milling quality, very low mixing times with low bread loaf volumes were typical of all the triticales studied. However, translocation of the HMW-GS from wheat chromosome 1D increased dough strength, particularly the HMW-GS 5+10. Among the phytochemicals studied, double nulls at Gli-1 loci of Pegaso NILs had the highest total policosanols and total phenolic acid contents.Slight variation to wheat phenolic acid composition and contents were observed with waxy wheat and triticale lines.

The construction of high-performance vessels like the F50 catamaran has traditionally prioritized advanced composite materials and performance-driven design. However, there is a growing need to incorporate sustainable materials and practices, with their performance in marine applications remaining relatively unknown. This study aims to address this gap by investigating the feasibility of using flax laminates as an environmentally friendly alternative for frequently damaged components, specifically the stern extension.Mechanical testing of flax laminates revealed lower stiffness per fiber areal weight compared to literature values and supplier data sheets, primarily attributed to moisture uptake in the flax material. These findings highlight the significance of considering real-world environmental conditions and specific application requirements when evaluating the mechanical properties of flax composites. Despite the mechanical challenges, environmental analysis demonstrated that the flax alternative for the stern extension offers promising benefits. It exhibits a carbon-positive characteristic, resulting in lower energy consumption during production, and comparable waste production to the original carbon fiber extension. However, it is important to note that these advantages are based on idealized theoretical data, and further optimization is required to address variations in resin usage and the strength of the cured composite.To address the weight discrepancies among the fleet, currently rectified by corrector weights, a practical solution is proposed utilizing flax composite layups. Selective implementation of the flax stern extension on the lightest one-third of the fleet can effectively balance weight distribution without compromising overall yacht performance. This strategy allows SailGP to incorporate sustainable materials while maintaining uniformity and performance across all participating yachts. By considering the environmental impact and structural considerations, this study provides valuable insights for the development of sustainable marine composites and encourages further research in optimizing the performance and reliability of flax-based laminates in marine applications. / Vid konstruktion av högpresterande segelbåtar som F50-katamaranen har man traditionellt prioriterat avancerade kompositmaterial och prestandadriven design. Det finns ett växande önskemål av att införliva hållbara material och metoder i dessa båtar men materialens prestanda i marina applikationer är relativt okända. Denna studie syftar till att öka kunskapen genom att undersöka möjligheten att använda linfiberbaserade laminat som ett miljövänligt alternativ för komponenter som ofta skadas. Specifikt studeras en förlängning av akterspegeln som fungerar som ett lock runt roderinfästningen.Mekanisk provning av linbaserade laminat visade lägre styvhet per fiberytvikt jämfört med värden från litteraturen och leverantörsdatablad, främst tillskrivet fuktupptag i linfibrerna. Dessa resultat understryker betydelsen av att beakta verkliga miljöförhållanden och specifika tillämpningskrav när man utvärderar de mekaniska egenskaperna hos linkompositer. Trots de mekaniska utmaningarna visade miljöanalyser att linalternativet för akterförlängningen erbjuder lovande fördelar. Den ger lägre koldioxidutsläpp genom lägre energiförbrukning under produktionen och ungefär samma avfallsproduktion jämfört med den ursprungliga kolfiberförlängningen. Det är emellertid viktigt att notera att dessa fördelar är baserade på idealiserade teoretiska data, och ytterligare optimering krävs för att hantera variationer i hartsanvändning och styrkan hos den härdade kompositen.För att komma till rätta med viktskillnader mellan olika båtar, som för närvarande korrigeras med korrigeringsvikter, föreslås en praktisk lösning med användning av linkompositlaminat. Selektiv implementering av akterförlängningar av lin på den lättaste tredjedelen av flottan kan bidra till att balansera ut viktskillnader utan att påverka den totala yachtprestandan. Denna strategi gör det möjligt för SailGP att införliva hållbara material samtidigt som enhetlighet och prestanda bibehålls för alla deltagande yachter. Genom att ta hänsyn till miljöpåverkan och strukturella överväganden ger denna studie värdefulla insikter för utvecklingen av hållbara marina kompositer och uppmuntrar till ytterligare forskning för att optimera prestanda och tillförlitlighet hos linbaserade laminat i marina applikationer.

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Road Tra c legislation prescribes constraints on the forces/loads which vehicles may exert on the road at contact surfaces or load points. These constraints have bearing on speci c contact surfaces or groups of contact surfaces. The constraints are in the form of maximum force values and maximum ratios, which may exist between forces. The forces exerted by a vehicle on the road is determined by a combination of the vehicle's own mass, dimensional characteristics, and the mass and position of its cargo. The mass and position of the cargo can be modelled by only considering its centroid. The centroid's position is linked to a certain cargo arrangement. It is necessary, in terms of legal constraints, to distinguish between legally permissable- and non-permissable arrangements. Methods are proposed in this dissertation to determine the borders for the position of the centroid according to cargo-mass, for a variety of vehicle con gurations. The determination of borders for the position of the centroid is the result of a three part process. Firstly, the legal limits are translated to mathematical inequalities that must be satis ed for the forces at contact surfaces. Secondly, conservative parametric estimates for the forces, in terms of the position and the mass of the centroid of a given vehicle, must be derived. Finally these estimates are incorporated into the load constraints and an enclosed permissable area for the centroid is found. These position constraints are suitable inputs to solution methods of various cargo arrangement problems. Linear programmes which can solve certain general arrangement problems by utilising the position constraints on the centroid, were successfully developed. Solutions are presented for the arrangement of pallet-freight, as well as the arrangement of cargo units with asymetrical centroids over the length or width of a vehicle's cargo area. / AFRIKAANSE OPSOMMING: Padvervoerwetgewing skryf grense op kragte/laste voor wat voertuie by kontakoppervlakke of laspunte, op die pad mag uitoefen. Hierdie voorskrifte het betrekking op spesi eke laspunte en groepe van laspunte. Die voorskrifte is in die vorm van maksimum laswaardes by laspunte en maksimum ratio's wat tussen sekere laste mag bestaan. Die laste wat 'n voertuig op die pad uitvoer word bepaal deur 'n kombinasie van die voertuig se eie massa, dimensionele eienskappe, sowel as sy vrag se massa en posisie. Die vrag se massa en posisie kan gemodelleer word deur slegs die massamiddelpunt daarvan te beskou. Die massamiddelpunt se posisie word gekoppel aan 'n bepaalde vragrangskikking. Dit is nodig om, in terme van wetlike voorskrifte, te kan onderskei tussen wetlik toelaatbare en -ontoelaatbare rangskikkings. Metodes word in hierdie proefskrif voorgestel waarmee daar grense vir die posisie van die vragmassamiddelpunt bepaal kan word na gelang van die vragmassa, vir 'n verskeidenheid van voertuigkon gurasies. Die bepaling van grense vir die posisie van die vragmassamiddelpunt is die resultaat van 'n drieledige proses. Eerstens word die wetlike beperkings herlei na wiskundige ongelykhede waarbinne laste by kontakoppervlakke moet val. Tweedens word konserwatiewe parametriese beramings vir die laste verkry in terme van die ligging en massa van die vragmassamiddelpunt vir 'n gegewe voertuig. Laastens word hierdie beramings in die lasbeperkings opgeneem om 'n afgebakende toelaatbare gebied vir die vragmassamiddelpunt se posisie te verkry. Hierdie posisiebeperkings is geskik om as inset te dien in die oplossingmetodes van 'n verskeidenheid van vragrangskikkingsprobleme. Line^ere programme wat sekere algemene rangskikkingsprobleme kan oplos deur die aanwending van posisiebeperkings op die vragmassamiddelpunt, is suksesvol ontwikkel. Oplossings word aangebied vir die rangskikking van paletvrag, asook die rangskikking van vrageenhede met asimmetriese massamiddelpunte oor die lengte of breedte van 'n voertuig se vragarea.

A distribuição de pesos moleculares (DPM) de um polímero afeta as propriedades mecânicas, térmicas e reológicas do material. Além disso, a análise em tempo real de uma reação de polimerização é uma tarefa complicada e, consequentemente, os procedimentos de controle devem ser baseados em valores gerados pelos modelos. Por isso, é extremamente importante ter dados confiáveis sobre distribuições de pesos moleculares, melhorar a eficiência dos métodos existentes e desenvolver novos métodos capazes de prever as heterogeneidades das reações de polimerização. Experimentalmente, a DPM pode ser obtida usando técnicas como a cromatografia de permeação em gel. Para predizer a DPM, vários métodos foram desenvolvidos nas ultimas décadas. Um dos principais é o dos momentos estatísticos, baseado em conceitos puramente estatísticos, que não conseguem descrever completamente a DPM. Além disso, as aproximações com método de Galerkin usam polinômios ortogonais - no caso especifico polinômios de Laguerre - cujos coeficientes são calculados empregando os momentos estatísticos e a distribuição é gerada resolvendo um número de equações definido pelo usuário, relacionado à precisão desejada. Enfim, o método das funções geradoras de probabilidades foi utilizado para prever as DPMs, porém necessitando uma inversão da transformada de Laplace, que introduz problemas numéricos nem sempre possíveis de serem resolvidos. No presente trabalho, o sistema rigoroso de equações diferenciais ordinárias foi resolvido, com objetivo de reduzir as imprecisões e as limitações introduzidas pelas aproximações. Obter diretamente a DPM completa requer a resolução de um sistema contendo cerca de 2Nmax até 3Nmax equações diferenciais ordinárias rígidas, tarefa que há alguns anos era inviável devido a limitações relacionadas à capacidade de cálculo. Foi modelada a DPM para uma reação de polimerização radicalar livre de estireno e de metacrilato de metila. Um interesse especial foi dado à taxa de terminação que é, no momento, um dos temas mais investigados em polimerização por radicais livres. Os resultados das simulações foram comparados com dados experimentais tirados de reatores convencionais e, subsequentemente, com dados experimentais provenientes de um millireactor não convencional. / It is well known that the molecular weight distribution (MWD) of a synthetic polymer affects its mechanical, thermal and rheological properties. Furthermore, the on-line analysis for polymerization reaction is a difficult task and, consequently, the control procedures must rely on values given by models. As such, it is extremely important to have reliable data on the MWD, improve the efficiency of existing methods and develop new ones to predict the heterogeneities of polymerization reactions. Experimentally, the MWD can be obtained using techniques such as Gel Permeation Chromatography (GPC). To predict the MWD, many methods have been developed over the last decades. One of the main methods is the statistical moment treatment, which is based on a pure statistical concept and do not describe the whole MWD. Moreover, Galerkin approximation uses orthogonal polynomials -in general Laguerre polynomials- whose coefficients are calculated exploiting the statistical moment definition and the distribution is generated by solving a user-defined number of equations based on the desired precision. Finally, probability-generating functions that have been used to predict MWDs require Laplace transforms inversions, introducing numerical issues that must be bypassed and are not always solvable. It has been decided to base the approach without adopting any of these methods but directly solving the rigorous ordinary differential equation (ODE) system in order to reduce the inaccuracies and the limitations introduced by approximations. The direct obtention of the MWD requires the resolution of a system containing approximately 2Nmax up to 3Nmax stiff ODE equations that, a few years ago, was unfeasible due computational time limitations. The MWDs for a free radical styrene polymerization system and a methyl methacrylate system have been modeled. A special focus was given to the termination rate constant, which is, at the present, one of the most investigated topics in free radical polymerization. The results of the simulations were compared to experimental data taken from conventional reactors and, subsequently, to experimental data coming from an unconventional millireactor.

A distribuição de pesos moleculares (DPM) de um polímero afeta as propriedades mecânicas, térmicas e reológicas do material. Além disso, a análise em tempo real de uma reação de polimerização é uma tarefa complicada e, consequentemente, os procedimentos de controle devem ser baseados em valores gerados pelos modelos. Por isso, é extremamente importante ter dados confiáveis sobre distribuições de pesos moleculares, melhorar a eficiência dos métodos existentes e desenvolver novos métodos capazes de prever as heterogeneidades das reações de polimerização. Experimentalmente, a DPM pode ser obtida usando técnicas como a cromatografia de permeação em gel. Para predizer a DPM, vários métodos foram desenvolvidos nas ultimas décadas. Um dos principais é o dos momentos estatísticos, baseado em conceitos puramente estatísticos, que não conseguem descrever completamente a DPM. Além disso, as aproximações com método de Galerkin usam polinômios ortogonais - no caso especifico polinômios de Laguerre - cujos coeficientes são calculados empregando os momentos estatísticos e a distribuição é gerada resolvendo um número de equações definido pelo usuário, relacionado à precisão desejada. Enfim, o método das funções geradoras de probabilidades foi utilizado para prever as DPMs, porém necessitando uma inversão da transformada de Laplace, que introduz problemas numéricos nem sempre possíveis de serem resolvidos. No presente trabalho, o sistema rigoroso de equações diferenciais ordinárias foi resolvido, com objetivo de reduzir as imprecisões e as limitações introduzidas pelas aproximações. Obter diretamente a DPM completa requer a resolução de um sistema contendo cerca de 2Nmax até 3Nmax equações diferenciais ordinárias rígidas, tarefa que há alguns anos era inviável devido a limitações relacionadas à capacidade de cálculo. Foi modelada a DPM para uma reação de polimerização radicalar livre de estireno e de metacrilato de metila. Um interesse especial foi dado à taxa de terminação que é, no momento, um dos temas mais investigados em polimerização por radicais livres. Os resultados das simulações foram comparados com dados experimentais tirados de reatores convencionais e, subsequentemente, com dados experimentais provenientes de um millireactor não convencional. / It is well known that the molecular weight distribution (MWD) of a synthetic polymer affects its mechanical, thermal and rheological properties. Furthermore, the on-line analysis for polymerization reaction is a difficult task and, consequently, the control procedures must rely on values given by models. As such, it is extremely important to have reliable data on the MWD, improve the efficiency of existing methods and develop new ones to predict the heterogeneities of polymerization reactions. Experimentally, the MWD can be obtained using techniques such as Gel Permeation Chromatography (GPC). To predict the MWD, many methods have been developed over the last decades. One of the main methods is the statistical moment treatment, which is based on a pure statistical concept and do not describe the whole MWD. Moreover, Galerkin approximation uses orthogonal polynomials -in general Laguerre polynomials- whose coefficients are calculated exploiting the statistical moment definition and the distribution is generated by solving a user-defined number of equations based on the desired precision. Finally, probability-generating functions that have been used to predict MWDs require Laplace transforms inversions, introducing numerical issues that must be bypassed and are not always solvable. It has been decided to base the approach without adopting any of these methods but directly solving the rigorous ordinary differential equation (ODE) system in order to reduce the inaccuracies and the limitations introduced by approximations. The direct obtention of the MWD requires the resolution of a system containing approximately 2Nmax up to 3Nmax stiff ODE equations that, a few years ago, was unfeasible due computational time limitations. The MWDs for a free radical styrene polymerization system and a methyl methacrylate system have been modeled. A special focus was given to the termination rate constant, which is, at the present, one of the most investigated topics in free radical polymerization. The results of the simulations were compared to experimental data taken from conventional reactors and, subsequently, to experimental data coming from an unconventional millireactor.

O impacto da oxidação com ozônio na transformação de compostos orgânicos de elevada massa molar (HMW) para o aumento da biodegradabilidade dos efluentes da indústria de celulose e papel foi investigado sob diferentes doses de ozônio. Os experimentos foram realizados utilizando-se os efluentes primário e de extração alcalina de duas indústrias de celulose sob dois valores iniciais de pH (12 e 7). Utilizou-se um reator em escala de laboratório equipado com um difusor de bolhas finas para a aplicação do ozônio. Os resultados revelaram o potencial da aplicação de ozônio como uma etapa de tratamento anterior ao processo biológico convencional. Para o efluente primário, a aplicação de 0,70 mg\'O IND.3\'/mL efluente elevou a razão DBO5/DQO de 0,18 para 0,35 e foi alcançada uma remoção de cor na ordem de 87%. Para o efluente de extração alcalina da indústria Howe Sound, a razão DBO5/DQO foi elevada de 0,07 para 0,15 (pH inicial 12) e para 0,20 (pH inicial 7) e obteve-se uma remoção de cor por volta de 44% com a aplicação de 0,80 mg\'O IND.3\'/mL efluente. Para o efluente de extração alcalina da indústria Catalyst Paper, obteve-se uma remoção de cor por volta de 78% e a razão DBO5/DQO foi elevada de 0,07 para 0,16 após a aplicação de uma dose de ozônio de 0,80 mg\'O IND.3\'/mL efluente. Essas modificações foram alcançadas por uma redução nas frações de elevada massa molar durante a aplicação de ozônio. Para o efluente primário, observou-se uma elevada redução da faixa de maior massa molecular ( > 2kDa) após a aplicação de 0,72 mg\'O IND.3\'/mL efluente. Alcançaram-se 85% e 61% de remoção da faixa superior a 5 kDa para os efluentes de extração alcalina da indústria Howe Sound sob pH inicial 7 e 12, respectivamente, com a aplicação de cerca de 0,72 mg\'O IND.3\'/mL efluente. A faixa de maior massa molar ( > 10 kDa) dos efluentes de extração alcalina da indústria Catalyst Paper foi removida com a aplicação de aproximadamente 0,80 mg \'O IND.3\'/mL efluente. O papel do ozônio molecular disponível sob pH neutro parece ser de fundamental importância quando o objetivo é a redução dos compostos de elevada massa molecular. / The impact of ozone oxidation in transforming high molecular weight (HMW) organic compounds in order to improve the biodegradability of pulp and paper effluents was investigated under different ozone doses. The experiments were conducted uppon a primary treated effluent and an alkaline bleach plant effluent taken from two pulp mills. The effluents were investigated under different initial pH (7 and 12). Ozone was applied using a semi-batch reactor equipped with fine bubble diffuser. The results showed the potential for using ozone as a pre-treatment to the conventional biological process. Applying 0.70 mg\'O IND.3\'/mLww to the primary treated effluent enhanced the ratio of BOD5/COD was from 0.18 to 0.35 and decreased the colour by 87%. The ratio of BOD5/COD was increased from 0.07 to 0.15 (initial pH 12) and to 0.20 (initial pH 7) and colour was reduced by 44% after applying 0.80 mg\'O IND.3\'/mLww to the alkaline bleach effluent from Howe Sound\'s mill. A similar behavior was observed after 0.80 mg\'O IND.3\'/mLww was applied to the alkaline bleach effluent from Catalyst\'s mill. The ratio of BOD5/COD was increased from 0.07 to 0.16 and the effluent colour decreased by 78%. These changes were primarily driven by reductions of the HMW fractions of the effluent during ozonation. Organics with molecular range higher than 2 kDa were completely removed from the primary treated effluent. Aproximately 85% and 61% of the organics higher than 5 kDa were removed from the Howe Sound\'s alkaline bleach effluent under initial pH 7 and 12, respectively, after applying 0.72 mg\'O IND.3\'/mLww. Organic compounds with molecular weight higher than 10 kDa were completely removed from the Catalyst\'s alkaline bleach effluent after applying 0.80 mg\'O IND.3\'/mLww. Molecular ozone available under neutral conditions seems to play an important role when the removal of the high molecular weight organic compounds is the main objective.

No description available.