Orientador: Watson Loh / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-23T09:25:24Z (GMT). No. of bitstreams: 1 Vitorazi_Leticia_D.pdf: 8026553 bytes, checksum: 24a29dda2e9119ceaca4900c75603b10 (MD5) Previous issue date: 2013 / Resumo: Este trabalho contempla estudos de sistemas que se organizam principalmente através de interações eletrostáticas e formam estruturas coloidais em solução aquosa. Uma parte do trabalho se insere na linha de pesquisa de autoassociação de sais complexos de surfatantes iônicos e polieletrólitos. Nesta proposta, há interesse em estudar os sais complexos de surfatantes catiônicos de alquiltrimetilamônio com diferentes tamanhos de cadeia alquila e os copolímeros em bloco, poli(ácido acrílico)-b-poli(acrilamida), de diferentes tamanhos de cadeia no bloco neutro, poli(acrilamida). Os copolímeros em bloco foram preparados por polimerização radicalar controlada viva e as soluções aquosas de sais complexos desses copolímeros e surfatantes foram caracterizadas por técnicas de espalhamento de luz e de raios-X a baixos ângulos. A mistura estequiométrica desses sais complexos forma dispersões coloidais de agregados com estrutura núcleo-casca, cuja estabilidade cinética depende do tamanho do bloco neutro do copolímero. O agregado núcleo-casca possui núcleo com estruturação interna cuja organização e estrutura depende de ambos, tamanho do bloco neutro e do surfatante. Estas estruturas são cúbicas para o surfatante dodeciltrimetilamônio e hexagonais para o cetiltrimetilamônio. O tamanho do agregado núcleo-casca também diminui com o aumento do bloco poli(acrilamida). Em casos extremos, o núcleo é tão pequeno que não se observa formação de núcleo com estrutura interna organizada. Outra parte do trabalho se insere na linha de pesquisa envolvendo estudos calorimétricos e estruturais de agregados formados por espécies poliméricas de carga oposta. Nesta segunda proposta, foi estudada a coassociação entre polieletrólitos: poli(ácido acrílico) e cloreto de poli(dialil dimetil amônio). Para isso, diferentes sequências de adição foram estudadas por medidas de espalhamento de luz, de potencial zeta e titulação calorimétrica isotérmica. Resultados indicaram que diferentes mecanismos de coassociação ocorrem, dependendo da sequência de adição, embora ambos os mecanismos sejam entropicamente favorecidos / Abstract: This work intends to study systems composed by oppositely charged species that forms colloidal structures in aqueous solution through electrostatic interactions. The first part aims at studying complex salts from ionic surfactants and polyelectrolytes. In this topic, the studies with complex salts with different chain lengths of cationic surfactants of alkyltrimethylammonium and neutral block size of block copolymers, poly(acrylic acid)-b-poly(acrylamide) will be considered. The block copolymers were prepared by controlled living radical polymerization. Aqueous solutions of complex salts from these copolymers and surfactants were characterized by light scattering and small angle X-rays scattering techniques. Stoichiometric aqueous mixtures of these complex salts form colloidal dispersions of core-shell aggregates, whose kinetic stability depends on the size of the neutral block copolymer. The core of core-shell aggregates display liquid-crystalline internal structure whose order and type of structure depends on the size of both neutral block and surfactant chain length. Aggregates formed by dodecyl surfactants display cubic phases while those containing hexadecyl ones form hexagonal phases at their internal structures. Smaller aggregates are formed when the poly(acrylamide) block increase. Another part of these studies, aims of understanding the complexation mechanisms of systems formed by electrostatic attraction between oppositely charged polymeric species. The systems are formed by association between the poly(acrylic acid) and poly(diallyl dimethyl ammonium) chloride. Different addition sequences were evaluated by light scattering, zeta potential and isothermal titration calorimetry techniques. Results indicated that different mechanisms of coassociation occur depending on the addition sequence, although both mechanisms are entropically favored / Doutorado / Físico-Química / Doutora em Ciências

Orientador: Marcelo Lancellotti / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T12:42:44Z (GMT). No. of bitstreams: 1 Amstalden_MariaCeciliaKrahenbuhl_M.pdf: 4328649 bytes, checksum: efc5c151f8382e97f2def6576eb633b6 (MD5) Previous issue date: 2013 / Resumo: Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: Note: The complete abstract is available with the full electronic document / Mestrado / Fármacos, Medicamentos e Insumos para Saúde / Mestra em Biociências e Tecnologia de Produtos Bioativos

Orientadores: Elza Cotrim Soares, Sarah Monte Alegre / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-18T22:40:52Z (GMT). No. of bitstreams: 1 Fioravante_Milena_M.pdf: 3241616 bytes, checksum: 06a63b1444ac4ae94958e122343557c9 (MD5) Previous issue date: 2011 / Resumo: Os objetivos deste estudo foram avaliar a perda de peso, a composição corporal e o gasto energético de repouso de pacientes durante o tratamento da hepatite crônica C com Interferon peguilado (PEG IFN) e ribavirina, comparando com os resultados obtidos antes do tratamento. Após seleção de 56 indivíduos, com o diagnóstico de hepatite crônica C, encaminhados para o ambulatório de hepatites virais no Gastrocentro da Unicamp, o presente estudo avaliou, prospectivamente, 42 pacientes que preencheram os critérios previamente estabelecidos. O estudo foi realizado em dois tempos diferentes: o primeiro, antes de iniciar o tratamento, e o segundo na 12ª semana de tratamento que consistia no uso semanal de injeções de PEG IFN alfa-2a (180 ?g) ou PEG IFN alfa-2b (1,5 ?g/kg) e ribavirina (1000 ou 1250 mg/dia). A avaliação do estado nutricional incluiu avaliação antropométrica de peso e altura para cálculo do índice de massa corporal (IMC), circunferência do braço, dobra cutânea tricipital, circunferência muscular do braço e circunferência abdominal. A composição corporal foi analisada por bioimpedância elétrica (BIA), sendo estimados os valores de massa magra em kilogramas e porcentagem de gordura corporal. O gasto energético de repouso de cada indivíduo foi obtido pelo método da calorimetria indireta e o consumo alimentar avaliado por recordatório de 24 horas e questionário de freqüência alimentar. Os exames laboratoriais foram aproveitados do prontuário médico. A amostra de indivíduos, com média de idade igual a 46,3 anos, foi composta por 30 (71,4%) homens e 12 (28,6%) mulheres. No momento basal do estudo, 40,5% dos pacientes eram eutróficos, 33,3% tinham sobrepeso e 26,2% apresentavam algum grau de obesidade. Os indivíduos apresentaram perda de peso significativa durante o tratamento (79,1 ± 15,6 vs. 75,7 ± 15 kg; p<0,001) com conseqüente redução de IMC (27,5 ± 5,2 vs. 26,3 ± 5 kg/m²; p<0,001), circunferência do braço (32,6 ± 3,8 vs. 31,3 ± 3,7 cm; p<0,001), dobra cutânea tricipital (18 ± 8,1 vs. 15,6 ± 7 mm; p<0,001), circunferência muscular do braço (27 ± 2,9 vs. 26,5 ± 2,8; p=0,008) e circunferência abdominal (97,8 ± 14,3 vs. 95,5 ± 14,1 cm; p<0,001). A perda de peso deu-se com redução significativa de gordura corporal (29 ± 8,2 vs. 26,7 ± 7,8%; p<0,001), sem redução de massa magra (55,6 ± 10 vs. 55 ± 10,2 kg; p=0,210). Houve redução significativa no consumo alimentar (2131 ± 890 vs. 1834 ± 699 kcal; p=0,012), avaliado pelo recordatório de 24 horas. Porém, não houve alteração no gasto energético de repouso (1168,2 ± 303 vs. 1151,3 ± 249 kcal; p=0,670) e no gasto energético de repouso corrigido pela massa magra (20,9 ± 3,7 vs. 21,1 ± 3,7 kcal/kg; p=0,864). Em conclusão, os pacientes com hepatite crônica C submetidos ao tratamento com interferon e ribavirina apresentaram importante perda de peso, observando-se redução significativa do consumo calórico, porém sem alteração do gasto energético de repouso. Mais estudos podem ser necessários para tentar elucidar as verdadeiras causas de perda de peso nesses pacientes / Abstract: The aim of this study was to evaluate weight loss, body composition and resting energy expenditure (REE) in patients during treatment of chronic hepatitis C with pegylated interferon (PEG IFN) and ribavirin, compared with the results obtained before treatment. After selection of 56 individuals with chronic hepatitis C, this study evaluated prospectively 42 patients who met the established criteria. The study was conducted at two different times: the first, before starting treatment, and the second at 12 weeks of treatment, which consisted in using weekly injections of PEG IFN alfa-2a (180 ?g) or PEG IFN alfa-2b (1,5 ?g/kg) and ribavirin (1000 or 1250 mg/d). The assessment of nutritional status included anthropometric measurements of body height and weight to calculate body mass index (BMI), arm circumference, triceps skinfoldthickness, arm muscle circumference and waist circumference. Body composition was determined by bioelectrical impedance analysis (BIA) and estimated values of fat free mass (FFM) in kilograms and percentage of body fat. The REE of each individual was obtained by indirect calorimetry and food intake assessed by 24- hour recall and food frequency questionnaire. Laboratory tests were drawn from medical records. The sample of individuals consisted of 30 (71.4%) men and 12 (28.6%) women. At baseline, 40.5% were eutrophic, 33.3% were overweight and 26.2% had some degree of obesity. Subjects had significant weight loss during treatment(79.1 ± 15.6 vs. 75.7 ± 15 kg, p <0.001) with consequent decrease in BMI (27.5 ± 5.2 vs. ± 26.3 5 kg / m², p <0.001), arm circumference (32.6 ± 3.8 vs. 31.3 ± 3.7 cm, p <0.001), triceps skinfold thickness (18 ± 8.1 vs. 15, 6 ± 7 mm, p <0.001), arm muscle circumference (27 ± 2.9 vs. 26.5 ± 2.8, p = 0.008) and waist circumference (97.8 ± 14.3 vs. 95.5 ± 14.1 cm, p <0.001). This weight decrease was accompanied by significant decrease in body fat (29 ± 8.2 vs. 26.7 ± 7.8%, p <0.001) and there was no decrease in FFM (55.6 ± 10 vs. ± 55 10.2 kg, p = 0.210). There was significant decrease in energy intake (2131 ± 890 vs. 1834 ± 699 kcal, p = 0.012) assessed by 24-hour recall. However, there was no change in REE (1168.2 ± 303 vs. 1151.3 ± 249 kcal; p=0.670) and REE corrected for FFM (20.9 ± 3.7 vs. 21.1 ± 3.7 kcal/kg; p=0.864). Our study of individuals with hepatitis C treatment showed that these patients had a significant weight loss and this was not associated with changes in energy expenditure. However, we observed a significant reduction in energy intake, pointing to a possible need for intervention measures to reduce damage / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

Orientador: João Sinézio de Carvalho Campos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T08:39:45Z (GMT). No. of bitstreams: 1 Bento_RonaldoEuzebio_M.pdf: 1080016 bytes, checksum: c783e50a51346a7d89eb82f52976eb49 (MD5) Previous issue date: 2011 / Resumo: Esse trabalho concentra os estudos na investigação das propriedades de resistência a tração e alongamento do compósito de Politetrafluoretileno (PTFE) com 60% de bronze após a substituição do tipo de PTFE utilizado na formulação desse compósito. Atualmente esse compósito utiliza PTFE convencional na formulação e o objetivo é alterar para PTFE modificado. A motivação para essa alteração deveu-se ao fato que o PTFE convencional apresenta disponibilidade limitada dificultando o desenvolvimento dos segmentos que utilizam os compósitos de PTFE com 60% de bronze. A escolha do PTFE modificado para a substituição do PTFE convencional na formulação do compósito de PTFE com 60% de bronze deveu-se ao fato que polímero puro de PTFE modificado apresenta propriedades mecânicas e químicas superiores ao polímero puro de PTFE convencional, além de não apresentar limitações de disponibilidade, possibilitando a continuidade do crescimento dos segmentos industriais. A escolha do compósito de PTFE com 60% de bronze deveu-se ao fato que essa formulação é a mais empregada no segmento automobilístico para a fabricação de anéis para amortecedores e retentores. Após a substituição da resina de PTFE, os resultados demonstraram que o compósito de PTFE modificado com 60% de bronze apresentou propriedades inferiores ao compósito fabricado com PTFE convencional. A queda dessas propriedades pode estar relacionada com possíveis micros fissuras na estrutura do compósito em virtude de ar preso durante o processo de fabricação / Abstract: This work focuses on research studies of the properties of tensile strength and elongation of the composite of Polytetrafluoroethylene (PTFE) with 60% bronze after replacing the type of PTFE used in the formulation of this compound. Currently, this composite uses conventional PTFE in the formulation and the objective is to change to modified PTFE. The motivation for this change was due to the fact that the conventional PTFE has limited availability hindering the development of the segments that use the PTFE composite with 60% bronze. The choice of PTFE modified PTFE to replace the conventional formulation of the composite with 60% PTFE bronze was due to the fact that pure polymer modified PTFE has superior mechanical and chemical properties of the pure polymer PTFE conventional, and not present availability limitations, enabling the continued growth of industries. The choice of the composite with 60% PTFE bronze due to the fact that this formulation is the most used in the automotive sector for the manufacture of rings and seals for shock absorbers / Mestrado / Ciencia e Tecnologia de Materiais / Mestre em Engenharia Química

Orientador: Sarah Monte Alegre / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-19T20:32:32Z (GMT). No. of bitstreams: 1 Carvalho_ThalytaMorandiRidolfide_M.pdf: 1082546 bytes, checksum: 8844f3f5a4c8f2d69eee5b1aa85f8f02 (MD5) Previous issue date: 2012 / Resumo: Mundialmente estimam-se 644.000 novos casos de câncer de cabeça e pescoço no mundo com dois terços dos casos ocorrendo em países em desenvolvimento. Os principais sinais e sintomas clínicos são dificuldade para engolir os alimentos, aumento do volume da região cervical, rouquidão, sangramento e em alguns casos dor que guiam o paciente à perda de peso. O presente estudo teve como objetivo avaliar o gasto energético basal e os fatores que mais influenciam na perda de peso de trinta e dois pacientes com carcinoma de células escamosas de cabeça e pescoço em estádios III e IV do sistema TNM antes e após 30 dias do término da radioterapia e quimioterapia,compreendidos numa faixa etária de 30 a 65 anos, de ambos os sexos. A seleção dos indivíduos foi realizada no ambulatório de Oncologia do Hospital das Clinicas -Universidade Estadual de Campinas. A coleta de dados realizou-se na Unidade Metabólica, 6° andar do HC-UNICAMP que englobou o preenchimento de um questionário com informações pessoais (idade, sexo, tabagismo), avaliação do estado nutricional (peso, altura e avaliação subjetiva global preenchida pelo próprio paciente), avaliação da composição corporal (bioempedância elétrica, circunferência braquial, prega cutânea do tríceps e circunferência muscular do braço), avaliação do gasto energético basal (calorimetria indireta), avaliação metabólica/bioquímica (colesterol total e frações, triglicérides, glicemia, insulinemia, adiponectina, leptina, fator de necrose tumoral (TNF-?), interleucina 1 (IL-1?), interleucina 6 (IL-6) e avaliação da sensibilidade à insulina (HOMA). Além disso os pacientes foram avaliados em relação à ingestão alimentar por meio do recordatório de 24 horas e do Índice de Alimentação Saudável. Os dados foram digitados em banco de dados utilizando-se o programa Excel e para a análise estatística utilizou-se o programa SAS para Windows versão 9.1.3. com nível de significância ? 5%. Nosso estudo mostrou que não podemos justificar a perda de peso pelo aumento do gasto energético basal e/ou diminuição do gasto energético basal, sendo a mesma influenciada por fatores derivados do tumor e pelo início de um processo inflamatório e sugerimos que o aporte nutricional precoce e a ressecção tumoral antes de iniciar o tratamento poderiam melhorar o prognóstico do paciente / Abstract: Worldwide, an estimated 644,000 new cases of head and neck cancer are diagnosed each year, with two- thirds of cases occurring in undeveloped countries. They are usually seen as a set of signs and symptoms which include lesions of the oral cavity, swelling of the neck, difficulty in swallowing food, hoarseness, bleeding and ultimately pain that in some cases can lead to malnutrition. Furthermore, the standard treatment increases weight loss. The main of this study was to evaluate the resting energy expenditure and the factors that had the most influence on weight loss of thirty two patients (aged between 30 and 65 years of both genders) with squamous cell carcinoma of head and neck in stage III and IV of the TNM system before and after 30 days of completion radiotherapy and chemotherapy. The selection of subjects was performed at the Hospital Oncology Clinic, University of Campinas. Data collection took place in the Metabolic Unit which included filling out a questionnaire with personal information such as (age, sex, smoker or non-smoker ...), assessment of nutritional status (weight, height and subjective global assessment completed by the patient), evaluation of body composition (bioelectrical impedance, arm circumference, triceps skinfold and arm muscle circumference), evaluation of resting energy expenditure (indirect calorimetry), evaluation of metabolic / biochemical factors (total cholesterol and fractions , triglycerides, glucose, insulin, adiponectin, leptin, tumor necrosis factor ? (TNF-?), interleukin 1 ? (IL-1?), interleukin 6 (IL-6) and evaluation of insulin sensitivity (HOMA). In addition, the patient was evaluated in relation to food intake by 24-hour recall and the Healthy Eating Index. The data were entered into the database using the program Excel and the statistical analysis used the SAS for Windows version 9.1. 3. with a significance level ? 5%. Our study demonstrated that we cannot justify the weight loss either by increasing the resting energy expenditure or decreasing; it is influenced by factors derived from the tumor and the beginning of an inflammatory process. Nutritional support and early tumor resection before starting treatment improves the nutritional prognosis / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

Orientador : Rosiane Lopes da Cunha / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T02:33:04Z (GMT). No. of bitstreams: 1 Takeuchi_KatiuchiaPereira_M.pdf: 1779769 bytes, checksum: 68792b5cd7f6aee9eaab0bdb1c4181d4 (MD5) Previous issue date: 2003 / Resumo: Neste trabalho, as interações entre as proteínas do leite-carragena-sacarose em meio aquoso foram estudadas em sistemas mantidos em pH 6,7 e submetidos a tratamento térmico de 70ºC por 30 minutos. Estas interações foram estudadas através da avaliação do comportamento reológico em cisalhamento sob regime oscilatório da mistura dos biopolímeros e sacarose, durante e após a gelificação. As propriedades mecânicas dos produtos gelificados foram analisadas em ensaios a altas deformações sob compressão uniaxial, possibilitando um estudo das características de rigidez e elasticidade dos géis formados. As propriedades reológicas foram fortemente influenciadas pela carragena, que mostrou interação com as proteínas do leite e favoreceu a característica elástica dos sistemas. O isolado protéico de soro (IPS) promoveu o fortalecimento da rede, enquanto que o caseinato de sódio pareceu diminuir a rigidez da rede do gel, pois beneficiou a característica viscosa dos sistemas. A sacarose favoreceu a interação do IPS com a carragena levando à formação de uma rede mais interconectada, portanto mais elástica e resistente à ruptura. As interações entre as proteínas do leite-carragena-sacarose também foram avaliadas através da medida do estado da água nestes sistemas por meio de calorimetria diferencial de varredura, com a determinação da fração de água livre e não-congelável e a temperatura de início de fusão. A quantidade de água não-congelável e a temperatura de início de fusão foram fortemente influenciadas pela sacarose, provavelmente pelo favorecimento de interações entre as proteínas e destas com a água. O tratamento térmico (70ºC por 30 min) permitiu a interação das proteínas do soro com as frações hidrofílicas da caseína e sua interação com a carragena. As interações que ocorreram entre as proteínas do leite após o tratamento térmico, relacionadas à agregação intermolecular ou intramolecular, foram analisadas através de eletroforese de gel de poliacrilamida. Essa análise permitiu verificar que as concentrações das proteínas presentes no sistema influenciam na quantidade das unidades livres em solução, possibilitando a interação delas com os outros componentes do sistema, como a água e a carragena / Abstract: Interactions among milk proteins-carrageenan-sucrose in aqueous medium were studied in systems at pH 6.7 and submitted to thermal treatment at 70ºC for 30 min. These interactions were studied by evaluation of rheological behavior under oscillatory and steady shear of biopolymers mixture and sucrose during and after gelation. The mechanical properties of gelified products were determined in studies under uniaxial compression at high deformations, allowing a study of the characteristics of rigidity and elasticity of formed gels. The rheological properties were strongly influenced by carrageenan, wich showed interactions with milk proteins and favored the elasticity characteristic of the systems. Whey protein isolate (WPI) favored the formation of a more strength network, while sodium caseinate seemed decrease the rigidity of the gel network, since improved the viscous characteristic of the systems. Sucrose enhanced the interaction between WPI and carrageenan causing the formation of a more elastic network and resistant to the rupture. The interactions among milk proteins-carrageenan-sucrose were evaluated by quantification of state of water in these systems using a differential scanning calorimetry, with determination of free and unfreezable water fractions and the melting temperature onset. The unfreezable water (UFW) and temperature onset were strongly influenced by sucrose, probably by the enhancement of interactions protein-protein and protein-water. The thermal treatment (70ºC for 30 min) supported the interactions between the whey protein with the hydrophilic fractions of casein and their interactions with carrageenan. The interactions between milk proteins after thermal treatment were analysed by polyacrylamide gel electrophoresis related to intermolecular and intramolecular aggregation. This analysis allowed to verify that the protein concentration of the system had an effect on the amount of the free units in solution, making possible the interactions of them with the other systems components, as water and carrageenan / Mestrado / Mestre em Engenharia de Alimentos

Orientador: Watson Loh / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T17:10:15Z (GMT). No. of bitstreams: 1 Silva_RodrigoCardosoda_D.pdf: 8247158 bytes, checksum: 473fe7463d68c6d0e0bc41282c54596d (MD5) Previous issue date: 2002 / Doutorado / Físico-Química / Doutor em Ciências

Heat of hydration is a property of Portland cement and a direct result of the chemical reaction between cement and water. The amount of heat released is dependent upon the cement mineralogical composition, curing temperature, water to cement ratio, and cement fineness. High temperature resulting from heat of hydration (thereon referred to as HOH) of cement can affect the hydration process, and consequently the kinetics of development of the mechanical properties of concrete. One of the main reasons triggering the interest in HOH of cement is its implication in thermal cracking of concrete. The high temperature gradient between the inner core and the outer surface of a concrete element is known to result in large tensile stresses that may exceed tensile strength, thus leading to early–age thermal cracking in mass concrete. This dissertation initially addresses accurately predicting the heat of HOH of Portland cement at seven days based on the heat flow data collected from isothermal calorimetry for a time interval of 0-84 h. This approach drastically reduces the time required to identify the seven day HOH of Portland cement. The second part of this study focuses on cement fineness and its critical role on the heat generated by Portland cement during hydration. Using a matrix of four commercially available Portland cements, representing a wide range of mineralogical composition, and subjecting each of the as-received cements to several grinding increments, a linear relationship was established between cement fineness and heat of hydration. The effect of cement fineness and mineralogical composition on HOH of Portland cement was then related through a mathematical expression to predict the HOH of Portland cement based on its mineralogical composition and fineness. Three expressions were proposed for the 1, 3 and 7 day HOH. The findings indicate that the equations developed, based on cement main phase composition and fineness, can be used to identify cements with high heat of HOH that may cause thermal cracking in mass concrete elements. Also, the equations can be used to correlate the HOH with the other properties of Portland cement for quality control and prediction of chemical and physical properties of manufactured Portland cement and concrete. Restrained shrinkage experiments results on mortar specimens prepared with cements of variable phase composition and fineness indicate that interaction of C3A and sulfate source is the prime phenomenon followed by cement fineness as the second main factor influencing concrete cracking. In order to minimize this effect, the third part of this study focused on studying alternatives that can lower the heat generated by concrete on hydration through the incorporation of nanomaterials; namely, graphene nanoparticles. The results indicate that incorporation of graphene a as replacement for Portland cement improves thermal diffusivity and electrical conductivity of the cement paste. Consequently, the use of graphene can trigger improvement of the thermal conductivity of concrete elements thus reducing the cracking potential of concrete. Measurements of HOH of graphene-cement paste, at w/c=0.5, using isothermal conduction calorimetry, indicate that incorporation of graphene up to 10% increases the length of the induction period while reduces the magnitude of the alite main hydration peak due to the filler effect. Furthermore, increasing the w/c ratio from 0.5 to 0.6 and graphene content from 1 % to 10% (as a partial replacement of cement) increases the 7 day HOH of Portland cement by 50 J/g. Isothermal conduction calorimetry heat flow curves show that incorporation of graphene particles up to 10% does not have significant effect on interaction of aluminates and sulfates sources since the time of occurrence of the C3A sulfate depletion peak is not affected by graphene substitution up to 10%. Full factorial statistical design and analysis conducted on compressive strength data of mortar specimens prepared at two w/c ratios, using cements of different finenesses and graphene content indicates that the quantity of graphene and the physical interaction due to variable w/c, graphene and cement fineness, have the smallest P-value among all the samples, representing the most significant impact on compressive strength of mortar samples. It appears that in graphene cement paste composites, addition of 1% graphene results in 21% reduction of Young’s modulus. Increasing the graphene content from 1% to 5% and/or 10% does not show significant effect on Young’s modulus. Similar trends can be observed in the hardness of graphene cement paste samples. In conclusion, partial replacement of Portland cement with graphene nanoparticles in concrete mixtures is a good alternative to lower the cracking potential in mass concrete elements.

Mineral and chemical admixtures are used today in almost all concrete mixtures to improve concrete fresh and hardened properties, and to enhance concrete durability. In this study, four mineral and four chemical admixtures were investigated: namely, metakaolin (MK), silica fume (SF), Class F fly ash (FA), blast-furnace slag (BFS), two high-range water reducers (SP), water reducer/retarder (WRD), and air-entrainer (AEA). The objective of this study is to assess the effects of commonly used mineral and chemical admixtures on the durability of the cementitious system. Two durability issues were addressed in this study: the potential of the cementitious system to generate heat, and sulfate durability. The properties studied here included heat of hydration (HOH) measurements using isothermal calorimetry, setting properties, compressive strength, and expansion on exposure to a sodium sulfate solution. X-ray diffraction was used to characterize the as-received materials and explain failure trends. The findings of this study indicate that silica fume inclusion sustains superior durability in comparison to the other mineral admixtures considered here. Replacement levels as low as 10% outperformed the other admixtures studied. Fly ash showed improvement in the workability of the mixes, but had the lowest compressive strength results and might pose challenges when the rate of strength gain is critical. However, Class F fly ash mixtures showed better performance than unblended mixtures when exposed to a sulfate source. Metakaolin mixes showed higher heat evolution among all the mixtures studied here. This can potentially lead to durability concerns, especially when temperature rise is a design concern. Blast-furnace slag also improved the workability of the mixes and the later compressive strength, but had mixed performances when examined for sulfate durability.

L'amélioration de la résolution en énergie des calorimètres hadroniques est adressée dans cette thèse. L'approche envisagée se base sur la technique du dual-readout qui consiste à détecter simultanément les radiations Cherenkov et la scintillation. La comparaison de ces deux signaux permet en effet de compenser les fluctuations observées dans la détection de gerbes hadroniques. Les grenats d'Aluminium et de Lutetium (LuAG), qui sont d'efficaces scintillateurs une fois activés avec des terres rares, peuvent aussi jouer le rôle de radiateur Cherenkov sous leur forme non-dopée. Les deux types de matériaux peuvent alors être assemblés pour former un calorimètre dual-readout performant. Dans l'objectif d'étudier la faisabilité de ce concept, les effets de la concentration en dopant et de l'addition de divers codopants sur le rendement lumineux et les propriétés temporelles ont été étudiés. Nous avons montré le rôle important de la technique de croissance choisie sur la nature et la concentration des défauts structuraux. La géométrie optimale, qui se base sur des monocristaux en forme de fibres, donne l'avantage à la technique de micro-pulling down. Cette technologie ne montre pas de meilleurs résultats que les techniques de Bridgman et de Czochralski mais a été retenue pour des raisons de coût et d'adaptabilité pour une production à grande échelle. L'optimisation des paramètres de croissance a permis la production de fibres monocristallines de LuAG dopées avec du Cérium présentant un rendement lumineux de 8000 photons par MeV et un bon comportement en tant que guide de lumière grâce à une qualité optique bien maitrisée. Des tests avec des faisceaux d'électrons et de pions, en conditions de calorimétrie à haute énergie, permettent désormais d'envisager la production d'un prototype à plus grande échelle / This thesis focuses on the improvement of the energy resolution of hadron calorimeters. The approach is based on dual-readout, which consists in the simultaneous detection of both scintillation and Cherenkov light. The comparison of these two signals allows a compensation of the energy fluctuations, which are inherent to the detection of hadronic showers. Lutetium Aluminium garnets (LuAG), which are efficient scintillators when activated with rare-earth dopants (i.e. Cerium), can also act as Cherenkov radiators when undoped. Both undoped and doped crystals can then be assembled to build an efficient dual-readout calorimeter. With the objective to investigate the feasibility of this concept, the effects of the doping concentration and the use of various co-dopant on the light output and the timing properties of LuAG were studied. The growth method was demonstrated to induce significant differences in the nature and concentration of structural defects. The optimum geometry, which is based on singlecrystals shaped into fibers, favors the micro-pulling down technique. This technology does not outperform Bridgman and Czochralski techniques but was chosen on bases of cost considerations and large scale productions abilities. The optimization of the growth parameters led to the production of single-crystalline fibers of Cerium-doped LuAG with a light output of 8000 photons per MeV and an adequate behavior as light guide due to a well-controlled optical quality. Test with electrons and pions in high energy calorimetry conditions allow to engage a future production of a larger-scale prototype