• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 20
  • 10
  • 4
  • 1
  • 1
  • Tagged with
  • 43
  • 8
  • 7
  • 7
  • 7
  • 6
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Life Cycle Assessment for Building Products - The significanse of the usage phase

Paulsen, Jacob January 2001 (has links)
<p>NR 20140805</p>
22

Microflora Found in a Selected Group of Food Products Enclosed in a Protective Wrapper

Ogden, William H. January 1949 (has links)
The purposes of this study are, first, to determine relative numbers and predominant types of bacterial organisms in the various food products studied; second, to evaluate the efficiency of the paper coverings of these foods; and third, to determine whether these products are potential sources of food poisoning.
23

Propriedades funcionais do albume e qualidade de ovos de galinha cobertos com concentrado proteico de soro de leite bovino / Functional properties of the albume and quality of eggs of hen covered with protéico concentrate of bovine milk serum

Alleoni, Ana Claudia Carraro 08 August 2003 (has links)
Orientador: Aloisio Jose Antunes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T16:03:54Z (GMT). No. of bitstreams: 1 Alleoni_AnaClaudiaCarraro_D.pdf: 4141640 bytes, checksum: db9a912da57044569b27e9e031edb1c0 (MD5) Previous issue date: 2003 / Resumo: As proteínas da clara do ovo de galinha têm sido extensivamente usadas como ingredientes em alimentos processados, devido a suas propriedades funcionais, tais como gelatinização e formação de espuma. Durante o armazenamento, podem ocorrer mudanças nas características físicas, microbiológicas, químicas e funcionais dos ovos, que dependem das condições de armazenamento. As vantagens de utilizar filmes e coberturas comestíveis podem ser justificadas pela manutenção das propriedades funcionais dos alimentos, através da diminuição da perda de umidade e da diminuição do transporte de gases (02 e CO2). A aplicação de cobertura em ovos com casca reduz a perda de peso e mantém a qualidade interna do produto. Os objetivos foram quantificar a perda de peso, os valores da unidade Haugh, o pH e os teores de s-ovalbumina do albume, além de determinar alterações na estabilidade da espuma da clara, no perfil de textura e na umidade espremível de géis da clara de ovos frescos e de ovos com e sem cobertura à base de concentrado protéico de soro de leite, armazenados a 25°C, por 3,7, 10, 14,21 e 28 dias. Durante todo o período de estocagem houve decréscimo dos valores de unidade Haugh e perda de peso, tanto para os ovos com cobertura como para os ovos sem cobertura. Já o pH do albume aumentou. A variação dos valores nos ovos com cobertura foi menor do que para os ovos sem cobertura. Os valores da unidade Haugh para ovos com cobertura foram semelhantes aos de ovos armazenados sob refrigeração, encontrados em referências bibliográficas, no mesmo período de armazenamento. O volume de líquido drenado foi maior (P < 0,01) em ovos sem cobertura do que em ovos com cobertura armazenados a 25°C, em todos os períodos de armazenamento. A diferença no terceiro dia de armazenamento foi de 59% entre os ovos com cobertura e ovos sem cobertura, e no vigésimo oitavo dia foi 202%. Durante o período de armazenamento, ocorreu um aumento do pH e do volume do líquido drenado nos ovos sem cobertura. O teor de s-ovalbumina foi maior em ovos sem cobertura, comparados aos ovos com cobertura, em todos os períodos de armazenamento (P<0,01). Após três dias, os ovos sem cobertura apresentaram aumento de 33% em relação aos ovos com cobertura. Já com 28 dias de armazenamento essa diferença passou para 205%. Em ovos com cobertura armazenados a 25°C, o pH ficou na faixa de 8, e o teor de s-ovalbumina permaneceu na faixa de 20%. No vigésimo oitavo dia de armazenamento o teor chegou a 27%. Houve correlação positiva entre o teor de s-ovalbumina com o volume de líquido drenado (R2 = 0,92 para ovos com cobertura e R2 = 0,94 para ovos sem cobertura). Quando aumentou o teor de s-ovalbumina, aumenta o volume de líquido drenado, e diminuiu a estabilidade da espuma. A dureza do gel do albume de ovos sem cobertura foi maior do que a de ovos com cobertura (P < 0,01), dentro de todos os períodos de armazenamento. Não houve efeito do tempo de armazenamento na dureza dos géis dos ovos sem cobertura. Em ovos cobertos, a regressão linear explicou 60% do comportamento da dureza em relação ao período de armazenamento. No caso da elasticidade, não houve interação entre período de armazenamento e a cobertura. Houve diferença entre as médias dentro de cada período, mas não durante o armazenamento. A maior elasticidade foi dos géis de ovos sem cobertura, comparados com os géis de ovos com cobertura. O índice de coesividade e a mastigabilidade de géis de ovos sem cobertura foi maior que o de géis de ovos com cobertura, em todos os períodos de armazenamento. A percentagem de umidade espremível (UE) de géis de clara de ovos com cobertura foi maior do que a de ovos sem cobertura em todo o período de estocagem / Abstract: Egg white proteins are extensively used as processed food because of their functional properties, as gelation and foam formation. Depending on the storage conditions, some physical, microbiological, chemical and functional changes may occur. Functional food properties may be preserved when foods are coated by edible films, since both the loss of moisture and the transport of O2 and CO2 are reduced. The objectives of this work were quantify the weight loss, the Haugh unit and the pH contents of s-ovalbumin in the albumen, determining changes in the stability of egg white foam, in the texture profile and in the expressible moisture of fresh egg white gels and eggs coated or not by whey protein concentrate 0NPc), under six storage periods (3, 7, 10, 14,21 and 28 days), at 25°C. During the storage period, independently of the coating, values of Haugh unit, weight loss and albumen pH decreased, and the differences among the values from the first to the last period were lower in the coated eggs. The Haugh unit values for coated eggs were similar to those found in bibliographic references when the same storage period is considered. For the six storage periods, the volumes of drained liquid in non-coated eggs were higher (P< 0.01). In the 3rd day the difference between the coated and the non-coated egg was 59%, and after 28 days that difference increased up to 202%. In the non-coated eggs, values of pH and volume of drained liquid increased during the storage. The content of s-ovalbumin was higher in the non-coated than in the coated eggs, independently of the storage period (P < 0.01). After 3 days, the content of s-ovalbumin was 38% higher than in the coated eggs, and after 28 days the difference between the values was 205%. In the coated eggs, stored at 25°C, the pH was around 8, and the content of s-ovalbumin remained in 20%; after 28 days, the value increased to 27%. A positive correlation was found between the content of s-ovalbumin and the volume of drained liquid (R2 = 0.92 for coated eggs, and R2 = 0.94 for non-coated eggs). When the content of s-ovalbumin increased, the volume of drained liquid also increased, and the foam stability decreased. Hardness of the albumen gel of non-coated eggs was higher than the coated eggs, during the whole storage period. For the non-coated eggs, the storage period did not affect the hardness of the gels, but for the coated eggs, a linear regression explained 60% of the behavior of the hardness as a function of the storage period. When considering the gel elasticity, no interaction was found between the storage period and the egg coating. Non-coated eggs exhibited gels with higher springiness than coated eggs. The same was found for the cohesiveness index and the gel chewiness, independently of the storage periods. However, the opposite was observed for the percentage of expressible moisture, where the values for coated eggs were higher than for non-coated eggs / Doutorado / Doutor em Alimentos e Nutrição
24

Ramification des revêtements inséparables en caractéristique p>0. / Ramification theory for inseparable coverings

Zalamansky, Gabriel 02 July 2015 (has links)
Dans cette thèse, on introduit la notion de revêtement potentiellement inséparable et on se propose de développer une théorie de la ramification pour ces derniers. Le langage utilisé est celui des schémas en groupoïdes. Après avoir établi quelques résultats préliminaires au chapitre 1, on prouve au chapitre 2 un théorème de quotient d'un schéma en groupoïdes par un sous-groupoïde. Au chapitre 3, on utilise ces résultats pour entreprendre l'étude générale du formalisme des revêtements inséparables. Enfin, au chapitre 4, on spécialise au cas des revêtements sous un schéma en groupes diagonalisable et on étudie en détail la structure de ces derniers. En particulier, on exprime le lieu Gorenstein de ces morphismes en fonction des constantes de structure du revêtement et on prouve dans ce cadre une formule analogue à la formule de Riemann-Hurwitz des revêtements ramifiés classiques. / In this thesis, we introduce the notion of inseparable coverings and we try to develop a ramification theory for such objects. We make use of the groupoid scheme formalism. In section 1, we establish preliminary results on scheme epimorphisms. We use these results in the next section to prove a quotient theorem for groupoid schemes.Then in section 3 we introduce the general formalism of inseparable coverings.Finally, in the last section we consider in greater details inseparable coverings given by the action of a diagonalizable group scheme. We compute the Gorenstein locus of these morphisms and we prove a formula analogous to the classical Riemann-Hurwitz formula.
25

Fibration theorems for collapsing Alexandrov spaces / 崩壊するAlexandrov空間に対するファイブレーション定理

Fujioka, Tadashi 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第22974号 / 理博第4651号 / 新制||理||1668(附属図書館) / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)教授 山口 孝男, 教授 藤原 耕二, 教授 入谷 寛 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
26

Decompositions, Packings, and Coverings of Complete Directed Gaphs with a 3-Circuit and a Pendent Arc.

Gwellem, Chrys 14 August 2007 (has links) (PDF)
In the study of Graph theory, there are eight orientations of the complete graph on three vertices with a pendant edge, K3 ∪ {e}. Two of these are the 3-circuit with a pendant arc and the other six are transitive triples with a pendant arc. Necessary and sufficient conditions are given for decompositions, packings, and coverings of the complete digraph with the two 3-circuit with a pendant arc orientations.
27

Decomposition, Packings and Coverings of Complete Digraphs with a Transitive-Triple and a Pendant Arc.

Lewenczuk, Janice Gail 15 December 2007 (has links) (PDF)
In the study of design theory, there are eight orientations of the complete graph on three vertices with a pendant edge, K3∪{e}. Two of these are the 3-circuit with a pendant arc and the other six are transitive triples with a pendant arc. Necessary and sufficient conditions are given for decompositions, packings and coverings of the complete digraph with each of the six transitive triples with a pendant arc.
28

On the degree of the canonical map of surfaces of general type

Fallucca, Federico 26 September 2023 (has links)
In this thesis, we study the degree of the canonical map of surfaces of general type. In particular, we give the first examples known in the literature of surfaces having degree d=10,11, 13, 14, 15, and 18 of the canonical map. They are presented in a self-contained and independent way from the rest of the thesis. We show also how we have discovered them. These surfaces are product-quotient surfaces. In this thesis, we study the theory of product-quotient surfaces giving also some new results and improvements. As a consequence of this, we have written and run a MAGMA script to produce a list of families of product-quotient surfaces having geometric genus three and a self-intersection of the canonical divisor large. After that, we study the canonical map of product-quotient surfaces and we apply the obtained results to the list of product-quotient surfaces just mentioned. In this way, we have discovered the examples of surfaces having degree d=10,11,14, and 18 of the canonical map. The remaining ones with degrees 13 and 15 do not satisfy the assumptions to compute the degree of the canonical map directly. Hence we have had to compute the canonical degree of these two families of product-quotient surfaces in a very explicit way through the equations of the pair of curves defining them. Another work of this thesis is the classification of all smooth surfaces of general type with geometric genus three which admits an action of a group G isomorphic to \mathbb Z_2^k and such that the quotient is a projective plane. This classification is attained through the theory of abelian covers. We obtained in total eleven families of surfaces. We compute the canonical map of all of them, finding in particular a family of surfaces with a canonical map of degree 16 not in the literature. We discuss the quotients by all subgroups of G finding several K3 surfaces with symplectic involutions. In particular, we show that six families are families of triple K3 burgers in the sense of Laterveer. Finally, in another work we study also the possible accumulation points for the slopes K^2/ \chi of unbounded sequences of minimal surfaces of general type having a degree d of the canonical map. As a new result, we construct unbounded families of minimal (product-quotient) surfaces of general type whose degree of the canonical map is 4 and such that the limits of the slopes K^2/ \chi assume countably many different values in the closed interval [6+2/3, 8].
29

Sustentabilidade na arquitetura e o estudo dos compostos orgânicos voláteis emitidos por componentes vinílicos em habitações / Sustainability in architecture and the study of volatile organic compounds emitted by vinyl components in housings

Chaves, André Luiz de Oliveira 02 June 2016 (has links)
Nas últimas décadas, o policloreto de vinila (PVC) tem sido cada vez mais utilizado na Construção Civil, em razão de suas propriedades que o condiciona a substituir outros materiais na execução das obras. Neste caso, tais propriedades são conferidas pela ação de aditivos incorporados na formulação deste polímero, que o torna capaz de ser utilizado em diferentes aplicações, sendo uma delas os revestimentos vinílicos para o recobrimento de superfícies no interior dos edifícios. Entretanto, em pesquisas internacionais, ocorridas a partir dos anos 1990, ficou comprovado que havia a presença de substâncias químicas, denominadas compostos orgânicos voláteis (COV), nestes revestimentos. Diante destes fatores, na presente pesquisa, propôs-se a identificação e quantificação destas substâncias químicas em revestimentos vinílicos para aplicação em pisos e paredes, e nos adesivos de contato (colas), por meio de técnicas analíticas: micro-extração de fase sólida e cromatografia gasosa acoplada a espectrômetro de massas e termogravimetria acoplada ao espectroscópio de infravermelho. Os resultados das análises qualitativas indicaram a presença de compostos pertencentes às classes químicas dos ésteres, éter glicólicos, alcanos, álcoois, cetonas, antioxidantes, ésteres de acetato, terpenos, tióis, organoclorados, solventes hidrocarbonetos e ácido cloreto, encontrados em sua maior parte nas amostras de linhas de piso vinílico e de adesivo de contato, pertencentes à uma das empresas líderes de mercado. Enquanto que as amostras de revestimentos vinílicos de parede não indicaram a presença de COV. Os resultados mais significativos nas análises quantitativas foram obtidos com as amostras de revestimentos, aplicados com adesivo de contato (cola), que indicaram concentrações de 216,41 mg/m³ e de 403,33 mg/m³ do composto 2-etil-1-hexanol, cujos valores estavam acima do limite máximo de 110 mg/m³ estipulado pela norma internacional MAK. Este e outros COVs identificados nesta pesquisa foram analisados quanto aos efeitos que podem causar na saúde humana, se ultrapassarem os limites máximos estabelecidos pelas normas internacionais, que vão desde os efeitos agudos, como irritações de pele, membranas mucosas dos olhos, nariz, garganta e trato respiratório, aos efeitos graves, como doenças neurológicas, distúrbios no ritmo cardíaco, depressão do sistema nervoso, asfixia e câncer. Além de ser verificado se os compostos orgânicos identificados podem contribuir para a redução da qualidade do ar interno das habitações. / In recent decades, the polyvinyl chloride has been increasingly used in civil construction, because of its properties that giving them conditions to replace other materials in the works of buildings. In this case, these properties are conferred by the incorporated additives in the formulation of the polymer, which makes it able to be used in different applications, being part of them the vinyl coverings, inside buildings. However, in international research that took place from the 1990s, it was proved that existed chemicals called volatile organic compounds (VOCs) in these coatings. Given these factors, in the present study aimed to identify and quantify these chemicals in vinyl coatings for use on floors and walls, and contact adhesives (glues), by means of analytical techniques: phase micro-extraction and solid gas chromatography coupled to mass spectrometry and thermogravimetry coupled with infrared spectroscopy. In this case, the additives are incorporated into the formulation of this polymer gives it properties which make it able to be used in different applications, as is the case of vinyl floorings and the vinyl wallpapers, which feature flexible and semi-flexible behavior, due to presence of plasticizers (phthalates) in their formulations. The results of the qualitative analysis showed the presence of compounds belonging to the chemical classes of esters, glycol ether, alkanes, alcohols, ketones, antioxidants, acetate esters, terpenes, thiols, chlorinated, hydrocarbon solvents and acid chloride, found mostly in samples of floor lines and vinyl contact adhesive, both sold in Brazil. While samples of vinyl wall coverings do not indicate the presence of VOC. The most significant results was obtained in quantitative analysis with samples of coatings applied with contact adhesive (glue), which indicated concentrations of 216.41 mg / m³ and 403.33 mg / m³ of the 2-ethyl-1-hexanol compound, whose values were above the upper limit of 110 mg / m³ stipulated by international standard MAK. This and other VOCs identified in this study were analyzed about the effects that can cause human health, if they exceed the limits set by international standards, ranging from the acute effects such as skin irritation, mucous membranes of the eyes, nose, throat and respiratory tract, to the chronic effects such as neurological disorders, heart rhythm disorders, nervous system depression, asphyxia and cancer. In addition to it is verified if the identified organic compounds may contribute to the reduction of the indoor air quality of the houses.
30

Moments en géométrie algébrique réelle / Moments in real algebraic geometry

Ancona, Michele 26 November 2018 (has links)
On sait que le nombre de racines réelles d’un polynôme à une variable de degré d et à coefficients réels est compris entre 0 et d. Au début des années 90, E. Kostlan prouve que le nombre moyen de racines vaut racine carrée de d, lorsque ces polynômes sont équipées d’une mesure de probabilité adéquate. Ce résultat possède une interprétation géométrique, où les polynômes apparaissent comme sections au-dessus de la sphère de Riemann, et ils peuvent s’étendre au cadre plus général de sections de fibrés en droites amples sur une surface de Riemann. Il s’agit ici du calcul de l’espérance mathématique du nombre de racines réelles de ces polynômes ou sections. Dans cette thèse, on calcule tous les moments centrés de ces variable aléatoires. Comme application de ce calcul, on prouve que la mesure de l’ensemble des polynômes ou sections dont le nombre de racines s’ écartent de la moyenne est majoré de façon effective en fonction de cet écart, un résultat de type concentration de la mesure en probabilité. Dans une deuxième partie, on présente des résultats analogue dans la théorie de Hurwitz réelle, où plutôt que du nombre de racines réelles d’un polynôme aléatoire, on considère le nombre de points critiques réels d’un revêtement ramifié aléatoire de la sphère de Riemann. On calcul la moyenne et tous les moments centrés du nombre de points critiques réels d'un revêtement aléatoire.Les techniques employées dans la preuve de ces résultats sont de nature analytique (noyau de Bergman, estimées L^2) et géométriques (multi-espaces d'Olver, formule de la coaire) / It is well known that the number of real roots of a real degree d polynomial is at most d. In the 90s, E. Kostlan proved that the average number of real roots equals the square root of d, once we equip the space of polynomials with some natural Gaussian measure. This result has a geometric interpretation, in which the real polynomials are sections of a line bundle over the Riemann sphere. We can extend this study in a more general case of a real Riemann surface equipped with ample line bundle and study the expected value of the number of real zeros of a random section. In this thesis, we compute all the central moments of these random variables. As an application, we prove that the measure of the space of real sections whose number of real zeros deviates from the expected one goes to zeros, as the degree of the line bundle goes to infinity.In a second part, we present analogues results in real Hurwitz theory, in which we study the real critical points of a random branched covering of the Riemann sphere. We compute the expected value of this number and also all the central moments.The techniques we use are of analytique nature (Bergman kernel, L^2 estimates) and gometric one (Olver multispaces, coarea formula)

Page generated in 0.0897 seconds