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  • 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.
151

Μελέτη περίσφιγξης υποστηλωμάτων ορθογωνικής διατομής μεγάλου λόγου πλευρών με ινοπλισμένα πολυμερή (FRP) και ινοπλέγματα σε ανόργανη μήτρα (TRM)

Φωτάκη, Αιμιλία 02 March 2015 (has links)
Αντικείμενο της παρούσας Διατριβής Διπλώματος Ειδίκευσης είναι η κατά βάση πειραματική διερεύνηση της αποτελεσματικότητας περίσφιγξης ορθογωνικών υποστυλωμάτων με μεγάλο λόγο πλευρών, ενισχυμένων με μανδύες ινοπλισμένων πολυμερών και σύνθετων υλικών ανόργανης μήτρας. Το πειραματικό πρόγραμμα διεξήχθη στο Εργαστήριο Μηχανικής και Τεχνολογίας Υλικών του Τμήματος Πολιτικών Μηχανικών του Πανεπιστημίου Πατρών. Το πρόγραμμα αυτό, περιελάμβανε δύο σειρές δοκιμίων. Η πρώτη περιελάμβανε έξι δοκίμια και η δεύτερη δέκα. Η κατηγοριοποίηση σε σειρές έγινε με βάση το λόγο πλευρών των δοκιμίων. Έτσι, την πρώτη σειρά αποτέλεσαν δοκίμια με λόγο πλευρών (3:1), ενώ τη δεύτερη δοκίμια με λόγο πλευρών (4:1). Ένα δοκίμιο από κάθε σειρά δοκιμάσθηκε χωρίς ενίσχυση και αποτέλεσε μέτρο σύγκρισης για όλα τα υπόλοιπα. Τρία δοκίμια από κάθε σειρά ενισχύθηκαν με τρείς στρώσεις FRP και με θυσάνους. Ακόμα, ένα δοκίμιο από κάθε σειρά ενισχύθηκε με δύο στρώσεις FRP, χωρίς χρήση θυσάνου. Επίσης, δύο υποστυλώματα από τη δεύτερη σειρά ενισχύθηκαν με δύο στρώσεις FRP, θυσάνους και δύο επιπρόσθετες στρώσεις FRP τύπου U, στις δύο μικρές πλευρές. Τέλος, ένα δοκίμιο από κάθε σειρά ενισχύθηκε με τέσσερις στρώσεις TRΜ, ενώ άλλο ένα με τέσσερις στρώσεις TRΜ και με θυσάνους. / The subject of this thesis is the experimental investigation of the effectiveness of confining rectangular columns with large aspect ratio, reinforced with fiber reinforced polymers and with tensile reinforced mortars. The experimental program was conducted at the Laboratory of Engineering and Technology of Materials in Civil Engineering, University of Patras. This program is consisted of two sets of samples. The first included six small scale columns and the second ten. The categorization in series was based on the aspect ratio of the specimens. So specimens with aspect ratio (3: 1) were included in the first series, while the second included specimens with aspect ratio (4: 1). One specimen from each series was tested without any reinforcement and became the comparison for all the rest. Three specimens from each series were reinforced with three layers of FRP and anchors. Still, a sample from each series was reinforced with two layers of FRP, without use of anchors. Also, two columns of the second series of amplified with two layers FRP, anchors and two additional layers of FRP type U, in the two smaller sides. Finally, a sample from each series was reinforced with four layers TRM, while another one to four layers TRM and anchors.
152

Ενίσχυση φέρουσας οπτοπλινθοδομής σε κάμψη με σύνθετα υλικά ανόργανης μήτρας και με ράβδους συνθέτων υλικών σε εγκοπές / Reinforcement of masonry in bending, using TRM and NSM

Παπαθανασίου, Μυρτώ 14 May 2007 (has links)
Ενίσχυση σε κάμψη στοιχείων οπτοπλινθοδομής με τη χρήση συνθέτων υλικών ανόργανης μήτρας και με την τοποθέτηση σύνθετων ράβδων σε εγκοπές. Περιγραφή διαδικασίας ενισχύσεων, πειραματικής διαδικασίας, πειραματικών αποτελεσμάτων και θεωρητική ανάλυση. / Reinforcement of masonry using TRM(Textiles Reinforced with mortar)and NSM.
153

Retail Experience Marketing : A study on customer perceptions of successful in-store experience marketing within retailing

Tengström, Michaela, Björkman, Hanna, Egardsson, Patricia January 2015 (has links)
It has been shown that in today’s society, businesses will need to consider not only selling products or services, but also experiences in order to fulfil customers’ increasing demand for more stimuli in purchase situations. Additionally, brick and mortar retailers will need to respond to the increased use of online sales channels through finding ways of attracting customers to their stores. One way of responding to both trends can be to practise Experience Marketing and thereby offer holistic, stimulating and memorable customer experiences at every purchase situation. With this insight, this thesis will investigate which specific factors that are perceived as important when creating successful in-store experiences. From this, the aim is to create a framework based on customers’ perceptions that can be useful for brick and mortar retailers when implementing experience marketing. Five propositions of what factors to include in order to create successful experiences are presented. These are tested and further developed through both quantitative and qualitative research. The empirical investigation results in the creation of a final suggested framework including the supported propositions, one new Additional Factor and several suggested subcategories within each factor. The final framework suggests following factors as important when creating successful experience marketing: Store Environment, Employee Characteristics, Senses and Additional Factor.
154

Data Transfer between Meshes for Large Deformation Frictional Contact Problems

Kindo, Temesgen Markos January 2013 (has links)
<p>In the finite element simulation of problems with contact there arises</p><p>the need to change the mesh and continue the simulation on a new mesh.</p><p>This is encountered when the mesh has to be changed because the original mesh experiences severe distortion or the mesh is adapted to minimize errors in the solution. In such instances a crucial component is the transfer of data from the old mesh to the new one. </p><p>This work proposes a strategy by which such remeshing can be accomplished in the presence of mortar-discretized contact, </p><p>focusing in particular on the remapping of contact variables which must occur to make the method robust and efficient. </p><p>By splitting the contact stress into normal and tangential components and transferring the normal component as a scalar and the tangential component by parallel transporting on the contact surface an accurate and consistent transfer scheme is obtained. Penalty and augmented Lagrangian formulations are considered. The approach is demonstrated by a number of two and three dimensional numerical examples.</p> / Dissertation
155

Building on a solid foundation : the use of bricks and mortar in house foundations in colonial New England

Hale, John P. January 2003 (has links)
This study is intended to provide the archaeologist with a solid understanding of the use of bricks and mortar in colonial New England and to examine the construction of New England colonial residential structures to determine if attributes exist that would allow the development of a regional diachronic or synchronic typology for aid in dating the structures either relatively or absolutely. This paper examines the technology involved in the produc ion of bricks and lime mortar, the construction of seventeenth and eighteenth century foundations, and the social environment that influenced the use of bricks. From the information presented in the paper, the archaeologist should gain an understanding of bricks as artifacts in the New England colonial landscape in order to improve the manner in which b licks are investigated and change the way in which archaeologists view, and therefore r -,cord information about, bricks, mortar, and foundations in Colonial New England. / Department of Anthropology
156

Possible Modifications to the Accelerated Mortar Bar Test (ASTM C1260)

Golmakani, Farideh 11 July 2013 (has links)
The Accelerated Mortar Bar test (AMBT) is rapid, reproducible, and perhaps the most widely used technique for examining the potential alkali-silica reactivity of aggregates. Unfortunately, this test is often unreliable as it may identify non-reactive aggregate as reactive and vice versa. With the aim of improving the accuracy of AMBT, two modifications to the current procedure were evaluated: 1) the maturity of mortar bars prior to alkali hydroxide exposure and 2) reduction of the storage temperature. The original and modified versions were performed on six aggregates with alkali-silica reactive (ASR) components, and their expansions and ASR classifications were compared. Results show that increasing the maturity had no significant impact on expansions. However, modifying the storage temperature to 60˚C and extending the period of testing to 28 days can be very effective in terms of more reliably identifying the existing falsely identified aggregates.
157

Possible Modifications to the Accelerated Mortar Bar Test (ASTM C1260)

Golmakani, Farideh 11 July 2013 (has links)
The Accelerated Mortar Bar test (AMBT) is rapid, reproducible, and perhaps the most widely used technique for examining the potential alkali-silica reactivity of aggregates. Unfortunately, this test is often unreliable as it may identify non-reactive aggregate as reactive and vice versa. With the aim of improving the accuracy of AMBT, two modifications to the current procedure were evaluated: 1) the maturity of mortar bars prior to alkali hydroxide exposure and 2) reduction of the storage temperature. The original and modified versions were performed on six aggregates with alkali-silica reactive (ASR) components, and their expansions and ASR classifications were compared. Results show that increasing the maturity had no significant impact on expansions. However, modifying the storage temperature to 60˚C and extending the period of testing to 28 days can be very effective in terms of more reliably identifying the existing falsely identified aggregates.
158

Kontaktanalyse dünnwandiger Strukturen bei großen Deformationen

Hartmann, Stefan, January 2007 (has links)
Zugl.: Stuttgart, Univ., Diss., 2007.
159

Improving corrosion resistance of post-tensioned substructures emphasizing high performance grouts /

Schokker, A. J. January 1999 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 306-312). Available also in a digital version from Dissertation Abstracts.
160

Υλικά και τεχνολογία κατασκευής των παλαιοχριστιανικών ψηφιδωτών της Βασιλικής του Αγίου Λωτ στην Ιορδανία

Γιαννακάκη, Μαρία 22 December 2009 (has links)
Το πρόγραμμα συντήρησης του μοναστηριακού συγκροτήματος του Αγίου Λωτ περιελάμβανε in situ επεμβάσεις συντήρησης, σωστική αποκόλληση και επανατοποθέτηση ενός από τα έξι ψηφιδωτά δάπεδα που βρίσκονταν στην Βασιλική και την ανασκαφή ενός ψηφιδωτού που είχε καταρρεύσει και κατακερματιστεί σε εκατοντάδες θραύσματα στην κλιτύ του λόφου, όπου βρίσκεται η Μονή. Η αποκόλληση του πρώτου ψηφιδωτού δαπέδου και η επακόλουθη ανακάλυψη ενός πρωιμότερου ψηφιδωτού δαπέδου κάτω από αυτό, καθώς και η εύρεση ενός ακόμα σε θραύσματα μας έδωσε την ευκαιρία να παρατηρήσουμε και να καταγράψουμε επιμελώς τις τεχνικές που χρησιμοποιήθηκαν στην κατασκευή των ψηφιδωτών. Ο χαρακτηρισμός επιλεγμένων δειγμάτων κονιαμάτων μας επέτρεψε να προσδιορίσουμε τη σύστασή τους και να ταυτοποιήσουμε το είδος των αδρανών και των προσμίξεων που εμπεριέχει. Οι τεχνικές που χρησιμοποιήθηκαν για την ανάλυση των κονιαμάτων είναι οι: η Περιθλασιμετρία κόνεως ακτίνων-Χ (XRD), η Ηλεκτρονική Μικροσκοπία Σάρωσης (SEM- EDS), η Φασματοσκοπία Απορρόφησης Υπερύθρου (FTIR) και η Οπτική Μικροσκοπία (ΟΜ). Επιπλέον, η πετρογραφική ανάλυση των ψηφίδων, που έγιναν από συνεργάτες του έργου, μας έδωσαν πληροφορίες σχετικά με την προέλευση των πρώτων υλών που χρησιμοποιήθηκαν. Μετά από αναλύσεις και λεπτομερή παρατήρηση, λάβαμε πληροφορίες σχετικά με τις πρώτες ύλες, την προετοιμασία των κονιαμάτων, την στρωματογραφία του ψηφιδωτού δαπέδου, την μέθοδο εκτέλεσης των εργασιών κατασκευής, αλλά και τον τρόπο επεξεργασίας της επιφάνειας. Οι διαφορές που παρατηρούνται στην στρωματογραφία και τη σύσταση των κονιαμάτων, όπως και στις ψηφίδες σε ψηφιδωτά που δημιουργήθηκαν σε διαφορετική χρονική περίοδο συμβάλλουν στην αρχαιολογική μελέτη και κυρίως στην κατανόηση της αρχιτεκτονικής ενότητας και μετατροπών που υπέστη κατά την διάρκεια της χρήσης του χώρου. / The conservation project at the monastic complex of Saint Lot involved the rescue lifting of one of the six mosaics which paved the basilica as well as the excavation of a second one that was found in hundreds of fragments fallen on the slope. The lifting of the first mosaic and the consequent discovery of fragments of an earlier mosaic floor underneath it, as well as the fragmentary state of the second mosaic gave us the opportunity to observe and record thoroughly the techniques employed in the construction of these mosaics. Characterization of selected mortar samples allowed the determination of their composition, identification of the aggregate and its additives. X-Ray Diffraction, Fourier transform infrared spectroscopy, Optical Microscopy and Scanning Electron Microscopy with EDS were the main techniques employed. Mineralogical analyses of tesserae samples, that was employed from other partners of the project, provided information about the provenance of the raw materials that were used. Through detailed observation and analysis, significant information on the raw material selection, preparation of mortars, bedding stratigraphy, method of execution, as well as aspects of tesserae cutting and surface finishing techniques were documented. The variation in the bedding stratigraphy, the composition of the mortars as well as the petrography of the tesserae between mosaics that were executed in different periods contribute in the study of the archaeological context and especially in understanding the succession of the renovation and modification phases of the building.

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