Direct design of reinforced concrete skew slabs / Laila Mahmoud Abd El Hafez (1986) 

Public ISBD Titre : Direct design of reinforced concrete skew slabs Type de document : texte imprimé Auteurs : Laila Mahmoud Abd El Hafez, Auteur ; Bhatt, P., Directeur de thèse Editeur : Glasgow : University of Glasgow Année de publication : 1986 Importance : 413 f. Présentation : ill. Format : 27 cm. Note générale : Thèse d'Etat: Génie Civil : West Yorkshire, University of Glasgow : 1986 Annexe f. 414 - 420 . - Bibliogr. f. 421 - 435 Langues : Anglais (eng) Mots-clés : Reinforced concrete slabs  Nonlinear analysis Finite element method Index. décimale : D000386 Résumé : This thesis presents the results of an experimental and theoretical study of reinforced concrete skew slabs designed using the elastic stress fields in conjunction with the yield criterion for reinforced concrete slabs. The elastic stress field is obtained from finite element program using uncracked stiffness and the yield criterion adopted is given by (M*x - Mx + M* cos²α)(M* sin²α - My) - (Mxy + M*α sinα cosα)² = 0 where Mx, My and Mxy are the elastic applied bending and torsion moments normal to the x and y axis at the ultimate load. M*x and M*α are the ultimate flexural moment capacities of the section normal to the x and skew axis respectively and α is the angle of skew between x and α axis. The experimental work was conducted on a "large scale" skew slabs. The models included slabs of uniform thickness and ribbed slabs. The major parameters were the angle of skew and the arrangement of steel in the slab viz orthogonal or skew directions. The theoretical work was done using the nonlinear finite element program based on the isoparametric Mindlin element. In order to allow for the development of cracks through the thickness, the "layer approach" was adopted. Nonlinear effects due to the yielding of steel, cracking and crushing of concrete were included. A nonlinear finite element program was used to study the spread of yielded zones in the slab, the effect of fixing the direction of crack at its first appearance, prediction of the true deflection at working loads from the elastic deflection at working loads and a careful study of the yield criterion itself. The results show that the design procedure adopted is viable but care has to be taken to ensure that punching shear failure does not occur at obtuse corners. Direct design of reinforced concrete skew slabs [texte imprimé] / Laila Mahmoud Abd El Hafez, Auteur ; Bhatt, P., Directeur de thèse . - Glasgow : University of Glasgow, 1986 . - 413 f. : ill. ; 27 cm. Thèse d'Etat: Génie Civil : West Yorkshire, University of Glasgow : 1986 Annexe f. 414 - 420 . - Bibliogr. f. 421 - 435 Langues : Anglais (eng) Mots-clés : Reinforced concrete slabs  Nonlinear analysis Finite element method Index. décimale : D000386 Résumé : This thesis presents the results of an experimental and theoretical study of reinforced concrete skew slabs designed using the elastic stress fields in conjunction with the yield criterion for reinforced concrete slabs. The elastic stress field is obtained from finite element program using uncracked stiffness and the yield criterion adopted is given by (M*x - Mx + M* cos²α)(M* sin²α - My) - (Mxy + M*α sinα cosα)² = 0 where Mx, My and Mxy are the elastic applied bending and torsion moments normal to the x and y axis at the ultimate load. M*x and M*α are the ultimate flexural moment capacities of the section normal to the x and skew axis respectively and α is the angle of skew between x and α axis. The experimental work was conducted on a "large scale" skew slabs. The models included slabs of uniform thickness and ribbed slabs. The major parameters were the angle of skew and the arrangement of steel in the slab viz orthogonal or skew directions. The theoretical work was done using the nonlinear finite element program based on the isoparametric Mindlin element. In order to allow for the development of cracks through the thickness, the "layer approach" was adopted. Nonlinear effects due to the yielding of steel, cracking and crushing of concrete were included. A nonlinear finite element program was used to study the spread of yielded zones in the slab, the effect of fixing the direction of crack at its first appearance, prediction of the true deflection at working loads from the elastic deflection at working loads and a careful study of the yield criterion itself. The results show that the design procedure adopted is viable but care has to be taken to ensure that punching shear failure does not occur at obtuse corners.

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Iron-uptake systems and transport in staphylococcus aureus / Ahmed Bensoltane (1992) 

Public ISBD Titre : Iron-uptake systems and transport in staphylococcus aureus Type de document : texte imprimé Auteurs : Ahmed Bensoltane, Auteur Editeur : Glasgow : University of Glasgow Année de publication : 1992 Importance : 143 f. Présentation : ill. Format : 27 cm. Note générale : Thèse de Doctorat : Microbiologie : Royaume-Uni, University of Glasgow : 1992 Bibliogr. f. 144 - 171 . - Annexe f. 172 - 179 Langues : Anglais (eng) Mots-clés : Iron-uptake systems Staphylococci isolated S. aureus strains Iron-chelators Thin layer chromatography Staphylococcus Index. décimale : D001392 Résumé : The main objective of this thesis was the characterisation of iron-uptake systems in staphylococci isolated from different sources and investigation of the possible role of these in pathogensis. The iron-uptake systems of S. aureus strains were investigated by growing the cells in the presence of different iron-chelators. With the synthetic iron-chelators, α,α-dipyridyl and EDDA, siderophores were produced which could not be detected by the Arnow assay for phenolates or the Csaky test for hydroxamates. They were detected by paper chromatography, by thin layer chromatography (TLC) and with the Chrome Azurol S (CAS, blue agar) plates of Schwyn and Neilands. The siderophore of S. aureus C336 was partially purified by solvent extraction, column chromatography and TLC and partially characterised as a phenolate. In the presence of the natural chelator, transferrin, staphylococci grew well but produced no detectable siderophore. As the rate of uptake of ⁵⁵Fe by staphylicocci was faster in the presence of transferrin than EDDA it appeared that staphylococci interacted directly with transferrin to obtain iron. Transferrin was radiolabelled with ¹²⁵-I and in competitive binding exoeriments to cells was indistinguishable from native transferrin. Radiolabelled transferrin bound rapidly to staphylococci, reaching saturation after approximately 20 minutes when approximately 350 and 206 molecules per cell were bound by S. aureus strains C336 and GRI-15586 respectively. The binding affinity of transferrin for staphylococci was low (8 x 10⁶ litres/mole) and cells were estimated to possess approximately 20000 binding sires for transferrin. In contrast to the pathogenic isolates of staphylococci, commensal strains of S. aureus from humans grew in the presence of EDDA but no siderophores were detectable with the CAS blue agar plates or the Arnow or Csaky assays. Addition of KCN to growing cultures of the commensals did not inhibit their growth, in contrast to the pathogenic isolates. It is concluded that staphylococci exhibit at least 3 responses to iron-restriction. They may interact directly with transferrin, produce siderophores or, in the case of commensals, grow without utilisation of iron. Pathogenic staphylococci may use the siderophore-mediated uptake system to provide iron in locations where transferrin is absent or present only in low concentration. Iron-uptake systems and transport in staphylococcus aureus [texte imprimé] / Ahmed Bensoltane, Auteur . - Glasgow : University of Glasgow, 1992 . - 143 f. : ill. ; 27 cm. Thèse de Doctorat : Microbiologie : Royaume-Uni, University of Glasgow : 1992 Bibliogr. f. 144 - 171 . - Annexe f. 172 - 179 Langues : Anglais (eng) Mots-clés : Iron-uptake systems Staphylococci isolated S. aureus strains Iron-chelators Thin layer chromatography Staphylococcus Index. décimale : D001392 Résumé : The main objective of this thesis was the characterisation of iron-uptake systems in staphylococci isolated from different sources and investigation of the possible role of these in pathogensis. The iron-uptake systems of S. aureus strains were investigated by growing the cells in the presence of different iron-chelators. With the synthetic iron-chelators, α,α-dipyridyl and EDDA, siderophores were produced which could not be detected by the Arnow assay for phenolates or the Csaky test for hydroxamates. They were detected by paper chromatography, by thin layer chromatography (TLC) and with the Chrome Azurol S (CAS, blue agar) plates of Schwyn and Neilands. The siderophore of S. aureus C336 was partially purified by solvent extraction, column chromatography and TLC and partially characterised as a phenolate. In the presence of the natural chelator, transferrin, staphylococci grew well but produced no detectable siderophore. As the rate of uptake of ⁵⁵Fe by staphylicocci was faster in the presence of transferrin than EDDA it appeared that staphylococci interacted directly with transferrin to obtain iron. Transferrin was radiolabelled with ¹²⁵-I and in competitive binding exoeriments to cells was indistinguishable from native transferrin. Radiolabelled transferrin bound rapidly to staphylococci, reaching saturation after approximately 20 minutes when approximately 350 and 206 molecules per cell were bound by S. aureus strains C336 and GRI-15586 respectively. The binding affinity of transferrin for staphylococci was low (8 x 10⁶ litres/mole) and cells were estimated to possess approximately 20000 binding sires for transferrin. In contrast to the pathogenic isolates of staphylococci, commensal strains of S. aureus from humans grew in the presence of EDDA but no siderophores were detectable with the CAS blue agar plates or the Arnow or Csaky assays. Addition of KCN to growing cultures of the commensals did not inhibit their growth, in contrast to the pathogenic isolates. It is concluded that staphylococci exhibit at least 3 responses to iron-restriction. They may interact directly with transferrin, produce siderophores or, in the case of commensals, grow without utilisation of iron. Pathogenic staphylococci may use the siderophore-mediated uptake system to provide iron in locations where transferrin is absent or present only in low concentration.

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A nonlinear finite element study of reinforced concrete beams / Akthem Abdulkarim Al Manaseer (1983) 

Public ISBD Titre : A nonlinear finite element study of reinforced concrete beams Type de document : texte imprimé Auteurs : Akthem Abdulkarim Al Manaseer, Auteur ; D. V. Phillips, Directeur de thèse Editeur : Glasgow : University of Glasgow Année de publication : 1983 Importance : 410 f. Présentation : ill. Format : 27 cm. Note générale : Thèse de Doctorat : Génie Civil : Royaume-Uni, University of Glasgow : 1983 Bibliogr. [28] f. - Annexe [16] f Langues : Anglais (eng) Mots-clés : Nonlinear -- finite element method Reinforced concrete beams Smeared crack approach Endochronic theory Isoparametric elements Modified newton-raphson approach Tension stiffening effects Index. décimale : D003383 Résumé : This thesis describes the development of plane stress, nonlinear finite element method of analysis for reinforced concrete beams. These include simple, deep, and T-beams, failing in flexure and in shear. The nonlinear response is assumed to be caused by concrete cracking, nonlinear biaxial stress-strain relations, and by the yielding of steel reinforcement. The smeared crack approach was used with two models for post cracking behaviour, one with a tension stiffening effect and the other with no-tension stiffening. The endochronic theory with some adaptations was used to account for all other uncracked zones. 8-noded isoparametric elements were used for concrete representation and 3-noded isoparametric elements for steel. A modified Newton-Raphson approach, was used for solving the nonlinear problem with both the constant and variable stiffness methods. This was based on the evaluation of a tangential elasticity matrix. The unbalanced nodal forces were obtained by the method of residual forces and convergence was checked using either a force or a displacement criteria. A nonlinear finite element program was developed where all, the required aspects to model the reinforced concrete structures were included. It was a main contention of this work that the nonlinear solution parameters had such an important influence on the solution process that an extensive study was required to determine their effects. This was carried out on simple and complex beams, and suitable guide lines were established. In particular tension stiffening effects were investigated and rejected in favour of a method with no-tension stiffening used in conjunction with controls on other solution parameters. Other parameters such as order of Gauss rule, shear retention factor, convergence tolerance, etc. were also studied in detail. An investigation into the behaviour of a range of deep beams including perforated deep beams and beams which were heavily reinforced, was undertaken. These beams failed both in shear and flexure. In most cases crack pattern, stress distribution, and load deflection curves were used to validate, (or otherwise), the performance of the proposed models and program. Finally a method is proposed for analysing T-beams using plane stress elements where the flange is treated separately and is connected to the web by a fictitious element. Other approximations are introduced in order to treat the problem as a two dimensional structure. A nonlinear finite element study of reinforced concrete beams [texte imprimé] / Akthem Abdulkarim Al Manaseer, Auteur ; D. V. Phillips, Directeur de thèse . - Glasgow : University of Glasgow, 1983 . - 410 f. : ill. ; 27 cm. Thèse de Doctorat : Génie Civil : Royaume-Uni, University of Glasgow : 1983 Bibliogr. [28] f. - Annexe [16] f Langues : Anglais (eng) Mots-clés : Nonlinear -- finite element method Reinforced concrete beams Smeared crack approach Endochronic theory Isoparametric elements Modified newton-raphson approach Tension stiffening effects Index. décimale : D003383 Résumé : This thesis describes the development of plane stress, nonlinear finite element method of analysis for reinforced concrete beams. These include simple, deep, and T-beams, failing in flexure and in shear. The nonlinear response is assumed to be caused by concrete cracking, nonlinear biaxial stress-strain relations, and by the yielding of steel reinforcement. The smeared crack approach was used with two models for post cracking behaviour, one with a tension stiffening effect and the other with no-tension stiffening. The endochronic theory with some adaptations was used to account for all other uncracked zones. 8-noded isoparametric elements were used for concrete representation and 3-noded isoparametric elements for steel. A modified Newton-Raphson approach, was used for solving the nonlinear problem with both the constant and variable stiffness methods. This was based on the evaluation of a tangential elasticity matrix. The unbalanced nodal forces were obtained by the method of residual forces and convergence was checked using either a force or a displacement criteria. A nonlinear finite element program was developed where all, the required aspects to model the reinforced concrete structures were included. It was a main contention of this work that the nonlinear solution parameters had such an important influence on the solution process that an extensive study was required to determine their effects. This was carried out on simple and complex beams, and suitable guide lines were established. In particular tension stiffening effects were investigated and rejected in favour of a method with no-tension stiffening used in conjunction with controls on other solution parameters. Other parameters such as order of Gauss rule, shear retention factor, convergence tolerance, etc. were also studied in detail. An investigation into the behaviour of a range of deep beams including perforated deep beams and beams which were heavily reinforced, was undertaken. These beams failed both in shear and flexure. In most cases crack pattern, stress distribution, and load deflection curves were used to validate, (or otherwise), the performance of the proposed models and program. Finally a method is proposed for analysing T-beams using plane stress elements where the flange is treated separately and is connected to the web by a fictitious element. Other approximations are introduced in order to treat the problem as a two dimensional structure.

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A numerical study of plate anchors embedded in sand / Zein Eddine Merouani (1988) 

Public ISBD Titre : A numerical study of plate anchors embedded in sand Type de document : texte imprimé Auteurs : Zein Eddine Merouani, Auteur ; D. M. Wood, Directeur de thèse Editeur : Glasgow : University of Glasgow Année de publication : 1988 Importance : 213, [15] f. Présentation : ill. Format : 30 cm. Note générale : Mémoire de Master : Civil Engineering : Royaume-Uni, University of Glasgow : 1988 Mémoire de Master en Génie Civil Bibliogr. f. 203-213. - Annexes [15] f. Langues : Anglais (eng) Mots-clés : Ground anchors Non-linear analysis Finite element analysis Sand Stress-strain model Index. décimale : Ms00288 Résumé : The work described in this thesis begins with an elstic analysis of ground anchors in which several assumptions were made. Some of these assumptions limited the applicability of the analysis but some useful insights into the stress distribution around ground anchors were obtained. However, a more realistic non-linear analysis was required before any definitive conclusion could be drawn. Finite element analysis appeared to be the most appropriate method. However, since the behaviour of sand is rather complex ( dilatancy, softening,...) an appropriate stress-strain model was then necessary. After a review of several constitutive models for sands, Vermeer's model which has the merit of being relatively simple yet comprehensive, has been studied in detail. However, this model does not describe softening behaviour since this is not a material property of a continuum. For this reason among others, it was decided that little advantage would be gained by implementing the model into the finite element program. Insteal, a simple linear elastic-perfectly plastic model based on the Mohr-Coulomb yield criterion was employed in the finite element analyses. The effects of soil propertiers, embedmant depth and initial stress conditions were studied as well as the effects of sand inhomogeneity and test scale. Contours representing the stress distribution around the anchor and yield propagation during the loading history were plotted. This gave an insight into the progressive mechanism of failure occuring in the soil mass. The results from the finite element analyses were based on the so-called k₄ failure load concept which appeared to give satisfactory results for loose sands. A numerical study of plate anchors embedded in sand [texte imprimé] / Zein Eddine Merouani, Auteur ; D. M. Wood, Directeur de thèse . - Glasgow : University of Glasgow, 1988 . - 213, [15] f. : ill. ; 30 cm. Mémoire de Master : Civil Engineering : Royaume-Uni, University of Glasgow : 1988 Mémoire de Master en Génie Civil Bibliogr. f. 203-213. - Annexes [15] f. Langues : Anglais (eng) Mots-clés : Ground anchors Non-linear analysis Finite element analysis Sand Stress-strain model Index. décimale : Ms00288 Résumé : The work described in this thesis begins with an elstic analysis of ground anchors in which several assumptions were made. Some of these assumptions limited the applicability of the analysis but some useful insights into the stress distribution around ground anchors were obtained. However, a more realistic non-linear analysis was required before any definitive conclusion could be drawn. Finite element analysis appeared to be the most appropriate method. However, since the behaviour of sand is rather complex ( dilatancy, softening,...) an appropriate stress-strain model was then necessary. After a review of several constitutive models for sands, Vermeer's model which has the merit of being relatively simple yet comprehensive, has been studied in detail. However, this model does not describe softening behaviour since this is not a material property of a continuum. For this reason among others, it was decided that little advantage would be gained by implementing the model into the finite element program. Insteal, a simple linear elastic-perfectly plastic model based on the Mohr-Coulomb yield criterion was employed in the finite element analyses. The effects of soil propertiers, embedmant depth and initial stress conditions were studied as well as the effects of sand inhomogeneity and test scale. Contours representing the stress distribution around the anchor and yield propagation during the loading history were plotted. This gave an insight into the progressive mechanism of failure occuring in the soil mass. The results from the finite element analyses were based on the so-called k₄ failure load concept which appeared to give satisfactory results for loose sands.

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Quinone methides related to 1-naphthol / Nourreddine Beghidja (1986) 

Public ISBD Titre : Quinone methides related to 1-naphthol Type de document : texte imprimé Auteurs : Nourreddine Beghidja, Auteur ; J. Carnduff, Directeur de thèse Editeur : Glasgow : University of Glasgow Année de publication : 1986 Importance : 118 f. Présentation : ill. Format : 27 cm. Note générale : Mémoire de Master : Chemistry Department : Ecosse, University of Glasgow : 1986 Mémoire de Master en Génie Chimique Bibliogr. f. 114-118 Langues : Anglais (eng) Mots-clés : Naphthol Quinone methides Carbon disulphide Dibromoethane Paraisomer Dihydrophenol Methyl-naphthoquinonemethide Index. décimale : Ms00286 Résumé : This thesis contains three short reviews as follows: 1/ Reaction of 1-naphthol with electrophiles 2/ Formylation of 1-naphthol 3/ Preparation methods and different types of reactionsof quinone methides. Repetition of treatment of 1-naphthol with carbon disulphide and then dibromoethane gives the two isomeric quinonemethides (A) and (B) and not, as claimed earlier, exclusively the para isomer. The major product of this reaction is proved to be the ortho one by detailed analysis of its spectra and by reduction via a dihydroderivative to 2-methyl-1-naphthol which was prepared independently for comparaison. The para isomer is present in very small amount but it can be isolated by chromatography and its structure confirmed spectroscopically. This thesis describes an investigation of a specific route to the para isomer. Several methods to formylate 1-naphthol were investigated. The Gattermann Adams reaction proved most effective. The dihydrophenol (c) was made from 4-formyl-1-naphthol but attempts using a wide range of oxidising agents failed to convert it to (A). The 2-bromoderivative also failed undergo clean oxidation. 2-Methyl-naphthoquinonemethide (D) was prepared by the CS₂ reaction and characterised, but 2-chloro- and 2-bromonaphthols failed to give the corresponding quinone methide. Changing the solvent of the original reaction of 1-naphthol gave the two isomers in the ratio (1:1). The two isomers were successfully isolated and fully characterised and their spectra is reported. The nmr spectra of (A) were found to be affected by the presence of acid. Quinone methides related to 1-naphthol [texte imprimé] / Nourreddine Beghidja, Auteur ; J. Carnduff, Directeur de thèse . - Glasgow : University of Glasgow, 1986 . - 118 f. : ill. ; 27 cm. Mémoire de Master : Chemistry Department : Ecosse, University of Glasgow : 1986 Mémoire de Master en Génie Chimique Bibliogr. f. 114-118 Langues : Anglais (eng) Mots-clés : Naphthol Quinone methides Carbon disulphide Dibromoethane Paraisomer Dihydrophenol Methyl-naphthoquinonemethide Index. décimale : Ms00286 Résumé : This thesis contains three short reviews as follows: 1/ Reaction of 1-naphthol with electrophiles 2/ Formylation of 1-naphthol 3/ Preparation methods and different types of reactionsof quinone methides. Repetition of treatment of 1-naphthol with carbon disulphide and then dibromoethane gives the two isomeric quinonemethides (A) and (B) and not, as claimed earlier, exclusively the para isomer. The major product of this reaction is proved to be the ortho one by detailed analysis of its spectra and by reduction via a dihydroderivative to 2-methyl-1-naphthol which was prepared independently for comparaison. The para isomer is present in very small amount but it can be isolated by chromatography and its structure confirmed spectroscopically. This thesis describes an investigation of a specific route to the para isomer. Several methods to formylate 1-naphthol were investigated. The Gattermann Adams reaction proved most effective. The dihydrophenol (c) was made from 4-formyl-1-naphthol but attempts using a wide range of oxidising agents failed to convert it to (A). The 2-bromoderivative also failed undergo clean oxidation. 2-Methyl-naphthoquinonemethide (D) was prepared by the CS₂ reaction and characterised, but 2-chloro- and 2-bromonaphthols failed to give the corresponding quinone methide. Changing the solvent of the original reaction of 1-naphthol gave the two isomers in the ratio (1:1). The two isomers were successfully isolated and fully characterised and their spectra is reported. The nmr spectra of (A) were found to be affected by the presence of acid.

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Reinforcement around embedded anchorages for post-tensioned prestressed concrete / Messaoud Souici (1988)

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A sulphur isotope study of the Caledonian granites of Britain and Ireland / Rabah Laouar (1987) 

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The influence of the support on the behaviour of supported metal catalysts in hydrocarbon hydrogenation reactions / Belkacem Boumarafi (1986) 

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