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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.
11

Comparison Of Compressive Strength Test Procedures For Blended Cements

Ulker, Elcin 01 September 2010 (has links) (PDF)
The aim of this thesis is to twofold, in order to demonstrate the variabilities that can be faced within the compressive strength of blended cements, one blended cement namely CEM IV / B (P-V) 32.5N is selected and the 28-day compressive strength is obtained by 16 different laboratories following TS EN 196-1 standard. Later, to show the variabilities that could be faced by different standards, three different cement types were selected and their compressive strengths are determined following two procedures first with TS EN 196-1, later with similar procedure described in ASTM. The strength of cement is determined by TS EN 196-1 in Turkey that is the same for all types of cements. However, American cement producers use different standards for testing the strength of Portland cement and blended cements. The main difference is the amount of water utilized in producing the cement mortar. It was observed that for Portland and Portland composite cements / there is not any significant difference in between the compressive strength results of cement mortars prepared by both methods. However, for pozzolanic cements, there is much deviance in the compressive strength results of cement mortars prepared by TS EN 196-1.
12

Building a framework for predicting the settlements of shallow foundations on granular soils using dynamically measured soil properties

Kacar, Onur 27 June 2014 (has links)
In this dissertation, the framework is being developed for a new method to predict the settlements of shallow foundations on granular soil based on field seismic and laboratory dynamic tests. The new method combines small-strain seismic measurements in the field with nonlinear measurements in the field and/or in the laboratory. The small-strain shear modulus (Gmax ) of granular soil and the stress dependency of Gmax is determined from the shear wave velocity measurements in the field. Normalized shear modulus (G/Gmax ) versus log shear strain(log [gamma]) curves are determined from field or laboratory measurements or from empirical relationships. The G/Gmax -- log [gamma] curves and Gmax values are combined to determine the shear stress-shear strain response of granular soil starting from strains of 0.0001% up to 0.2-0.5%. The shear stress-shear strain responses at strains beyond 1.0-2.0 % are evaluated by adjusting the normalized shear modulus curves to larger-strain triaxial test data. A user defined soil model (MoDaMP) combines these relationships and incorporates the effect of increasing confining pressure during foundation loading. The MoDaMP is implemented in a finite element program, PLAXIS, via a subroutine. Measured settlements from load-settlement tests at three different sites where field seismic and laboratory dynamic measurements are available, are compared with the predicted settlements using MoDaMP. Predictions with MoDaMP are also compared with predictions with two commonly used methods based on Standard Penetration and Cone Penetration tests. The comparison of the predicted settlements with the measured settlements show that the new method developed in this research works well in working stress ranges. The capability of the new method has significant benefits in hard-to-sample soils such as in large-grained soils with cobbles and cemented soils where conventional penetration test methods fail to capture the behavior of the soil. The new method is an effective-stress analysis which has applicability to slower-draining soils such as plastic silts and clays. / text
13

Προστασία γεωμεμβρανών με γεωυφάσματα: αποτελέσματα και συσχετίσεις κατά ΕΝ 13719

Κονδύλη, Μαριάννα - Αφροδίτη 27 August 2007 (has links)
Αντικείμενο της διατριβής αυτής είναι η εργαστηριακή διερεύνηση της εφαρμογής του πρότυπου ΕΝ 13719 με το οποίο εκτιμάται η προστασία που παρέχουν γεωυφάσματα σε γεωμεμβράνες έναντι αστοχίας λόγω μηχανικών καταπονήσεων. Για την εκτέλεση των εργαστηριακών δοκιμών σχεδιάστηκε και κατασκευάστηκε κατάλληλη εργαστηριακή διάταξη καθώς και σύστημα μέτρησης παραμορφώσεων σύμφωνα με τις προβλέψεις του πρότυπου ΕΝ 13719. Ελέγχθηκαν συνολικά 16 μη υφασμένα γεωυφάσματα από ίνες πολυπροπυλενίου. Τα γεωυφάσματα προέρχονται από έξι διαφορετικούς κατασκευαστές και επιλέχτηκαν έτσι ώστε να καλύπτεται ικανό εύρος τιμών για τις φυσικές και μηχανικές ιδιότητές τους (μάζα ανά μονάδα επιφάνειας από 186 g/m 2 έως 1407 g/ m2, πάχος 1.6 mm έως 10.1 mm, αντοχή σε εφελκυσμό 11.5 kΝ/m έως 103.4 kN/m και αντοχή σε διάτρηση 2.1 kN έως 16.4 kN). Οι τιμές του δείκτη προστασίας που προσδιορίστηκαν σύμφωνα με το πρότυπο ΕΝ 13719, κυμαίνονται μεταξύ 22.6x103 kPa έως 59.5x103 kPa. Στο πλαίσιο της διερεύνησης, έγιναν παρατηρήσεις σχετικά με την ανισοκατανομή του εφαρμοζόμενου φορτίου στη βάση του προσομοιωμένου αδρανούς με βάση το μέγεθος και την κατανομή των παραμορφώσεων που αποτυπώνονται σε φύλλο μολύβδου. Η ανομοιομορφία των παραμορφώσεων ή των βυθίσεων του φύλλου μολύβδου είναι έντονη για την ονομαστική τάση των 300 kPa και μειώνεται όσο αυξάνεται η ονομαστική τάση (σε 600 kPa και 1100 kPa). Επιπλέον, διερευνήθηκε η εξέλιξη με το χρόνο της συμπίεσης του συνόλου των υλικών που συνθέτουν την εργαστηριακή διάταξη καθώς και η επίδραση του περιορισμού της χρονικής διάρκειας της δοκιμής (από 100 hr σε 25 hr ) τόσο στις μετρούμενες παραμορφώσεις όσο και στον υπολογιζόμενο δείκτη προστασίας. Τέλος, διερευνήθηκε η δυνατότητα συσχέτισης των τιμών του δείκτη προστασίας κατά ΕΝ 13719 με φυσικές και μηχανικές ιδιότητες των γεωυφασμάτων τόσο για σειρές γεωυφασμάτων από έναν κατασκευαστή όσο και για το σύνολο των γεωυφασμάτων που ελέγχθηκαν. Κατά την διάρκεια εκτέλεσης δοκιμής κατά ΕΝ 13719, η συνολική συμπίεση της εργαστηριακής διάταξης στο στάδιο σταθερού φορτίου οφείλεται πιθανότατα στη συμπίεση των υπόλοιπων υλικών της εργαστηριακής διάταξης και όχι στο ίδιο το γεωύφασμα. Το γεωύφασμα αναμένεται να έχει εξαντλήσει τη συμπιεστότητά του κατά το αρχικό στάδιο της δοκιμής, δηλαδή κατά την πρώτη ώρα, όπου το φορτίο αυξάνεται με σταθερό φορτίο έως ότου φτάσει τη μέγιστη προβλεπόμενη τιμή του. Τα πειραματικά δεδομένα χρόνου–συμπίεσης δοκιμών διάρκειας 25 hr προσαρμόζονται εξαιρετικά με καμπύλες της μορφής y= Alnx+B, επιτρέποντας την προεκβολή τους για χρονικό διάστημα 100 hr. Η πρόσθετη αναμενόμενη συμπίεση της εργαστηριακής διάταξης για το διάστημα 25 hr έως 100 hr δε σχετίζεται με το μέγεθος του εξωτερικά ασκούμενου φορτίου, δηλαδή προκύπτουν περίπου ίδιες μετακινήσεις για διαφορετικά φορτία. Οι δείκτες προστασίας που υπολογίζονται με τη δυσμενή υπόθεση ότι η πρόσθετη συμπίεση οφείλεται αποκλειστικά στη συμπίεση του ελαστικού υποστρώματος, διαφέρουν από 0% έως 1.4%, με μέσο όρο 0.6%, από τους δείκτες που υπολογίζονται από δοκιμές διάρκειας 25hr. Κατά συνέπεια, τα αποτελέσματα των δοκιμών με διάρκεια 25 hr είναι αντιπροσωπευτικά των αποτελεσμάτων που θα λαμβάνονταν εάν οι δοκιμές διαρκούσαν 100 hr και δίνουν μια πολύ καλή εκτίμηση του δείκτη προστασίας των γεωυφασμάτων. Για το σύνολο των γεωυφασμάτων που ελέγχθηκαν, οι τιμές του δείκτη προστασίας παρουσιάζουν αυξητική τάση με την αύξηση των τιμών των φυσικών ή/και των μηχανικών ιδιοτήτων των γεωυφασμάτων. Συσχετίσεις τόσο με τη μάζα ανά μονάδα επιφάνειας όσο και με τις μηχανικές ιδιότητες που ποιοτικά κυμαίνονται από πολύ καλές (γεωυφάσματα Geofabrics) έως ανύπαρκτες (γεωυφάσματα Synthetic Ind.). Συσχετίσεις του δείκτη προστασίας με το πάχος ή το ειδικό βάρος των γεωυφασμάτων είναι κατώτερες ποιοτικά της συσχέτισης με τη μάζα ανά μονάδα επιφάνειας. / This dissertation is a laboratorial investigation on the application of standard EN 13719. The purpose of this standard is to evaluate the protection provided to geomembranes by geotextiles, in order to avoid the failure due to mechanic stress. The tests (in laboratory) were conducted after designing and constructing a suitable device and a system of measurement for deformations according to the standard EN 13719 provisions. A total of 16 nonwoven polypropylene geotextiles, representing 6 manufacturers were checked in order to cover an adequate range of physical and mechanical properties (mass per unit area 186 g/m2 to 1407 g/m2, thickness 1.6mm to 10.1mm, tensile strength 11.5 kN/m to 103.4 kN/m and puncture resistance 2.1 kN to 16.4kN). The values of protection index obtained ranged between 22.6x103 kPa to 59.5 kPa. During the investigation, observations were made with respect to the nonuniform distribution of the applied load at the base of the standard aggregate, as represented by deformations of the metal sheet. This strain nonuniform distribution was more obvious for the smallest stress of 300 kPa. In addition, the total compression of the materials in the laboratorial device was examined and the influence of reduced test duration ( from 100 hr to 25 hr ) was evaluated. Finally, correlations were obtained between protection index and physical and mechanical properties of geotextiles from the same manufacturer and for all specimens. During the tests, the total compression of the materials in the laboratorial device under constant stress ( second stage ) was most probably due to all the materials except the geotextile. The geotextile perhaps had expended its compressibility at the first stage of the test when the stress was applied incrementally over a period of one hour. The compression – time data were filled by logarithmic curves in order to predict the compression at 100 hr. Protection index calculated for 100 hr varied from that for 25 hr by 0% to 1.4% with an average of 0.6%. Consequently, the results of testing for 25 hr were representative of those for 100hr and gave a very good estimation of the protection index . For the total of geotextiles tested, the protection index increased as the physical and mechanical properties increased. Correlations between protection index and mass per unit area and mechanical properties ranged from very good ( geotextiles Geofabrics) to nonexistent ( geotextiles Synthetic Ind.). Correlations between protection index and thickness or specific gravity were qualitatively lower than those between protection index and mass per unit area.
14

Προστασία Γεωμεμβρανών με Γεωυφάσματα: διερεύνηση συνθηκών ελέγχου κατά ΕΝ 13719

Μπλαντζούκας, Θεοφάνης 30 August 2007 (has links)
Αντικείμενο της Διατριβής αυτής είναι η εργαστηριακή διερεύνηση της εφαρμογής του πρότυπου ΕΝ 13719 με το οποίο εκτιμάται η προστασία που παρέχουν γεωυφάσματα σε γεωμεμβράνες έναντι αστοχίας λόγω μηχανικών καταπονήσεων. Για την εκτέλεση των εργαστηριακών δοκιμών σχεδιάστηκε και κατασκευάστηκε κατάλληλη εργαστηριακή διάταξη καθώς και σύστημα μέτρησης παραμορφώσεων σύμφωνα με τις προβλέψεις του πρότυπου ΕΝ 13719. Ελέγχθηκαν συνολικά 16 μη υφασμένα γεωυφάσματα από ίνες πολυπροπυλενίου. Τα γεωυφάσματα προέρχονται από έξι διαφορετικούς κατασκευαστές και επιλέχτηκαν έτσι ώστε να καλύπτεται ικανό εύρος τιμών για τις φυσικές και μηχανικές ιδιότητές τους (μάζα ανά μονάδα επιφάνειας από 186 g/ m 2 έως 1407 g/ m2, πάχος 1.6 mm έως 10.1 mm, αντοχή σε εφελκυσμό 11.5 kΝ/m έως 103.4 kN/m και αντοχή σε διάτρηση 2.1 kN έως 16.4 kN). Οι τιμές του δείκτη προστασίας που προσδιορίστηκαν σύμφωνα με το πρότυπο ΕΝ 13719, κυμαίνονται μεταξύ 22.6x103 kPa έως 59.5x103 kPa. Στο πλαίσιο της διερεύνησης, έγιναν παρατηρήσεις σχετικά με την ανισοκατανομή του εφαρμοζόμενου φορτίου στη βάση του προσομοιωμένου αδρανούς με βάση το μέγεθος και την κατανομή των παραμορφώσεων που αποτυπώνονται σε φύλλο μολύβδου. Η ανομοιομορφία των παραμορφώσεων ή των βυθίσεων του φύλλου μολύβδου είναι έντονη για την ονομαστική τάση των 300 kPa και μειώνεται όσο αυξάνεται η ονομαστική τάση (σε 600 kPa και 1100 kPa). Επιπλέον, διερευνήθηκε η εξέλιξη με το χρόνο της συμπίεσης του συνόλου των υλικών που συνθέτουν την εργαστηριακή διάταξη καθώς και η επίδραση του περιορισμού της χρονικής διάρκειας της δοκιμής (από 100 hr σε 25 hr) τόσο στις μετρούμενες παραμορφώσεις όσο και στον υπολογιζόμενο δείκτη προστασίας. Τέλος, διερευνήθηκε η δυνατότητα αντικατάστασης της προτεινόμενης από το πρότυπο διαδικασίας με άλλη απλούστερη και ταχύτερη στην εκτέλεσή της. Για το λόγο αυτό σχεδιάστηκε και κατασκευάστηκε κατάλληλη διάταξη, εκτελέστηκαν αντίστοιχες δοκιμές και τα αποτελέσματα συγκρίθηκαν με αυτά που προκύπτουν από δοκιμές που εκτελούνται εφαρμόζοντας το πρότυπο ΕΝ 13719. Κατά την διάρκεια εκτέλεσης δοκιμής κατά ΕΝ 13719, η συνολική συμπίεση της εργαστηριακής διάταξης στο στάδιο σταθερού φορτίου οφείλεται πιθανότατα στη συμπίεση των υπόλοιπων υλικών της εργαστηριακής διάταξης και όχι στο ίδιο το γεωύφασμα. Το γεωύφασμα αναμένεται να έχει εξαντλήσει τη συμπιεστότητά του κατά το αρχικό στάδιο της δοκιμής, δηλαδή κατά την πρώτη ώρα, όπου το φορτίο αυξάνεται με σταθερό φορτίο έως ότου φτάσει τη μέγιστη προβλεπόμενη τιμή του. Τα πειραματικά δεδομένα χρόνου–συμπίεσης δοκιμών διάρκειας 25 hr προσαρμόζονται εξαιρετικά με καμπύλες της μορφής , επιτρέποντας την προεκβολή τους για χρονικό διάστημα 100 hr. Η πρόσθετη αναμενόμενη συμπίεση της εργαστηριακής διάταξης για το διάστημα 25 hr έως 100 hr δε σχετίζεται με το μέγεθος του εξωτερικά ασκούμενου φορτίου, δηλαδή προκύπτουν περίπου ίδιες μετακινήσεις για διαφορετικά φορτία. Οι δείκτες προστασίας που υπολογίζονται με τη δυσμενή υπόθεση ότι η πρόσθετη συμπίεση οφείλεται αποκλειστικά στη συμπίεση του ελαστικού υποστρώματος, διαφέρουν από 0% έως 1.4%, με μέσο όρο 0.6%, από τους δείκτες που υπολογίζονται από δοκιμές διάρκειας 25hr. Κατά συνέπεια, τα αποτελέσματα των δοκιμών με διάρκεια 25 hr είναι αντιπροσωπευτικά των αποτελεσμάτων που θα λαμβάνονταν εάν οι δοκιμές διαρκούσαν 100 hr και δίνουν μια πολύ καλή εκτίμηση του δείκτη προστασίας των γεωυφασμάτων. Για το σύνολο των γεωυφασμάτων που ελέγχθηκαν, οι τιμές του δείκτη προστασίας παρουσιάζουν αυξητική τάση με την αύξηση των τιμών των φυσικών ή/και των μηχανικών ιδιοτήτων των γεωυφασμάτων. Η συσχέτιση του δείκτη προστασίας με φυσικές ή/και μηχανικές ιδιότητες μπορεί, ποιοτικά, να είναι από πολύ καλή έως και αδύνατη. Οι τιμές του δείκτη προστασίας που προέκυψαν από δοκιμές που εκτελέστηκαν με απλοποιημένη διάταξη και διαδικασίες (μηδενικός χρόνος διατήρησης σταθερού φορτίου, μια στρώση σφαιρών, διπλάσια ονομαστική τάση) διαφέρουν από 1% έως 24%, με μέσο όρο 10%, από τις τιμές που υπολογίζονται κατά ΕΝ 13719. Κατά συνέπεια, ενισχύεται η άποψη ότι η πρότυπη δοκιμή μπορεί να προσομοιωθεί πολύ ικανοποιητικά με χρήση απλούστερης εργαστηριακής διάταξης πετυχαίνοντας σημαντική μείωση του απαιτούμενου χρόνου για την εκτέλεσή της. / This dissertation is a laboratory investigation of the application of Standard EN 13719 which has been established in order to evaluate the protection provided to geomembranes by geotextiles against failure due to external mechanical loads. For the purposes of this investigation, a suitable device and a system for deformation measurement were designed and conducted according to the provisions of standard EN 13719. A total of 16 nonwoven polypropylene geotextiles, representing 6 manufacturers were tested in order to cover an adequate range of physical and mechanical properties (mass per unit area 186 g/m2 to 1407 g/m2, thickness 1.6mm to 10.1mm, tensile strength 11.5 kN/m to 103.4 kN/m and puncture resistance 2.1 kN to 16.4kN). The values of protection index obtained ranged between 22.6x103 kPa to 59.5 x103 kPa. During the investigation, observations were made with respect to the nonuniform distribution of the applied load at the base of the standard aggregate, as represented by deformations of the metal sheet. This strain nonuniform distribution was more pronounced for the smallest applied stress of 300 kPa. In addition, the total compression of the materials in the laboratory device was examined and the influence of reduced test duration (from 100 hr to 25 hr) was evaluated. Finally, correlations were obtained between protection index and physical and mechanical properties of geotextiles from the same manufacturer as well as for all samples tested. During the tests, the observed total compression of the materials in the laboratory device under constant stress (second stage) was most probably due to the rest of the materials and not to the geotextile itself. The geotextile is expected to have had expended its compressibility during the first stage of the test when the stress was applied incrementally over a period of one hour. The compression – time data were fitted by logarithmic curves in order to predict the compression at 100 hr. Protection index values calculated for a test duration of 100 hr varied from those measured for 25 hr by 0% to 1.4% with an average of 0.6%. Consequently, the results of testing for 25 hr were representative of those for 100hr and gave a very good estimation of the protection index . For the total of geotextiles tested, the protection index values increased as the physical and mechanical properties values increased. Correlations between protection index and mass per unit area and mechanical properties ranged from very good (Geofabrics geotextiles) to nonexistent (Synthetic Ind. geotextiles). Correlations between protection index and thickness or specific gravity were qualitatively lower than those between protection index and mass per unit area. The protection index values obtained from tests conducted with a simplified laboratory divice and simplified procedures (no time allowed for constant load, one layer of spheres, double values for applied stress) differed by 1% to 24%, with an average of 10%, from the protection index values obtained according to EN 13719. Accordingly, there are strong indications that the standard procedures can be adequately simulated using simpler laboratory device and procedures and reducing significantly the required testing time.
15

Laboratory tests for identification of sars-cov-2 during pandemic times in Peru: Some clarification regarding «diagnostic performance» / Las pruebas de laboratorio para la identificación de sars-cov-2 en tiempos de pandemia en el Perú: Algunas precisiones acerca del «rendimiento diagnóstico»

Maguiña, Jorge L., Soto-Becerra, Percy, Hurtado-Roca, Yamilee, Araujo-Castillo, Roger V. 01 July 2020 (has links)
Carta al editor / Revisión por pares
16

Dynamic Vehicle-Track Interaction of European Standard Freight Wagons with Link Suspension

Jönsson, Per-Anders January 2007 (has links)
The link suspension is the most prevailing suspension system for freight wagons in Central and Western Europe. The system design is simple and has existed for more than 100 years. However, still its characteristics are not fully understood. This thesis investigates the dynamic performance of freight wagons and comprises five parts: In the first part a review of freight wagon running gear is made. The different suspension systems are described and their advantages and disadvantages are discussed. The second part focuses on the lateral force-displacement characteristics of the link suspension. Results from stationary measurements on freight wagons and laboratory tests of the link suspension characteristics are presented. To improve the understanding of various mechanisms and phenomena in link suspension systems, a simulation model is developed. In the third part the multibody dynamic simulation model is discussed. The previous freight wagon model developed at KTH is able to explain many of the phenomena observed in tests. In some cases, however, simulated and measured running behaviour differ. Therefore, a new simulation model is presented and validated against on-track test results. The performance of standard two-axle freight wagons is investigated. The most important parameters for the running behaviour of the vehicle are the suspension characteristics. The variation in characteristics between different wagons is large due to geometrical tolerances of the components, wear, corrosion, moisture or other lubrication. The influence of the variation in suspension characteristics and other parameters on the behaviour of the wagon, on tangent track and in curves, is discussed. Finally, suggestions for improvements of the system are made. A majority of the traffic related track deterioration cost originates from freight traffic. With heavier and faster freight trains the maintenance cost is likely to increase. In the fourth part the possibility to improve ride comfort and reduce track forces on standard freight wagons with link suspension is discussed. The variation of characteristics in link suspension running gear is considerable and unfavourable conditions leading to hunting are likely to occur. Supported by on-track tests and multibody dynamic simulations, it is concluded that the running behaviour of two-axled wagons with UIC double-link suspension as well as wagons with link suspension bogies (G-type) can be improved when the running gear are equipped with supplementary hydraulic dampers. Finally in the fifth part the effects of different types of running gear and operational conditions on the track deterioration marginal cost — in terms of settlement in the ballast, component fatigue, wear and RCF — is investigated. Considerable differences in track deterioration cost per produced ton-km for the different types of running gear are observed. Axle load is an important parameter for settlement and component fatigue. Also the height of centre of gravity has significant influence on track deterioration, especially on track sections with high cant deficiency or cant excess. / QC 20100802
17

Prediction Of Geotechnical Properties Of Cohesive Soils From In-situ Tests: An Evaluation Of A Local Database

Yaman, Gokhan 01 January 2007 (has links) (PDF)
In any geotechnical design procedure, the fundemantal point to be initially clearified is the characterization of existing soil profile at a site. This requires a great deal of planning a suitable site investigation program including borings, sampling, laboratory and in situ testing etc. Laboratory and in-situ (field) tests are important tools leading to the estimation of soils properties in geotechnics. Beside laboratory tests, the measurement of engineering properties in situ is a continuously growing and developing trend, particularly in materials difficult to obtain perfect undisturbed samples. For the purpose of this study, two large volumed geotechnical investigation reports are collected from a wide archive of 30 years experiences. Different soil types are encountered during the study like alluvial deposits of soft to stiff cohesive materials, hard clays in appearance of highly weathered rocks. The in-situ tests mostly being focused and studied on are &ldquo / Pressuremeter Test&rdquo / and &ldquo / Standard Penetration Test&rdquo / on cohesive materails. Over 350 standard penetration test results are recorded together with the pressuremeter results of relevant soils. Besides, the corresponding laboratory test results of oedometer, triaxial loading and all index properties of soils are assembled. The results of in-situ tests are evaluated together with the results of laboratory tests performed on the samples obtained from related sites. The correlations between in-situ &amp / laboratory test results on shear strength, compressibility and deformation characteristics of soils are analysed and compared with the existing correlations in literature. The correlations are generally obtained to be in agreement with the ones in common literature in cases where the soil conditions, particularly saturation, are same in both laboratory and in-situ tests.
18

Um ambiente evolutivo para apoio ao projeto de antenas de microfita / An evolutionary environment to support the synthesis of microstrip antenna

Barra, Tiago Venturieri 18 January 2007 (has links)
Orientadores: Fernando Jose Von Zuben, Cynthia Cristina Martins Junqueira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-08T19:03:06Z (GMT). No. of bitstreams: 1 Barra_TiagoVenturieri_M.pdf: 6614671 bytes, checksum: 4facb72e441f3af7afdbfc42f31ca50b (MD5) Previous issue date: 2007 / Resumo: O estudo de antenas de micro?ta envolve a especi?cação de um amplo espectro de parâmetros físicos, e cada proposta de antena requer o emprego de algoritmos avançados de cálculo numérico para medidas de desempenho, como impedância de entrada, padrão de irradiação e ganho em faixas especí?cas de freqüência. O principal objetivo desse trabalho é desenvolver um ambiente computacional combinando um software de análise de estruturas eletromagnéticas, MStrip40, baseado no método dos momentos (MoM), e um método de busca evolutivo, denominado algoritmo genético. Buscam-se valores ótimos de parâmetros físicos de antenas de micro?ta, como comprimento e largura do elemento irradiador e da linha de alimentação, entre outros. São tratados vários tipos de antenas de micro?ta, e um elenco amplo de critérios de desempenho é considerado, mantendo sempre um valor baixo para o coe?ciente de onda estacionária na freqüência de projeto. A validação dos resultados gerados pelo ambiente computacional é alcançada através da fabricação da melhor antena obtida em cada caso de estudo, seguida por testes de desempenho do dispositivo físico fabricado, realizados em laboratórios especializados / Abstract: The study of microstrip antennas involves the speci?cation of a broad spectrum of physical parameters, and each antenna proposal requires the use of advanced algorithms of numerical calculus to measure the performance, such as input impedance, radiation pattern and gain in speci?c frequency bands. The main objective here is to develop a computational environment joining a software for electromagnetic structure analysis, called MStrip40 and based on the Method of Moments (MoM), together with an evolutionary search method founded on a genetic algorithm. The outcome is composed of optimal values for physical parameters of the microstrip antenna, such as length and width of the radiator element and of the feeding line. Several kinds of microstrip antennas are treated, and a wide range of performance criteria are considered, always keeping a low value for the coef?cient of stationary wave at the design frequency. The validation of the results produced by the computational environment is achieved by means of the manufacture of the best obtained antenna in each case study, followed by performance evaluation of the manufactured physical device, which is accomplished in dedicated laboratories / Mestrado / Engenharia de Computação / Mestre em Engenharia Elétrica
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Transporte de solutos em barreiras de material argiloso compactado (CCL) e geocomposto bentonítico (GCL): fluxos diretos, acoplados e comportamento membrana / Solute transport through compacted clay liner (CCL) and geosynthetic clay liner (GCL): direct and coupled flux and membrane behavior

Marcos Andrés Musso Laespiga 20 August 2008 (has links)
Neste trabalho foi analisado o comportamento de um solo argiloso compactado (CCL) da Fm. Corumbataí e de um geocomposto bentonítico (GCL) composto por bentonita \'NA\', frente a gradientes hidráulicos e químicos. As propriedades físicas e mineralógicas dos solos foram avaliadas, bem como determinados em ensaios de adsorção em lote os parâmetros das isotermas de Freundlich e Langmuir. Foi desenvolvido um equipamento para avaliar o comportamento membrana e poder calcular o coeficiente de eficiência químico-osmótico (\'ômega\') em ensaio de difusão-membrana. Os ensaios de advecção foram executados com o equipamento já existente no departamento de Geotecnia. Em todos os ensaios foram utilizadas soluções monoiônicas de \'KCL\' e \'CU\'CL IND.2\' 2\'H IND.2\'O\'. O valor do factor de retardamento Rd determinado no ensaio em lote (batch test) foi maior que o Rd medido no ensaio de advecção, enquanto que, no ensaio de difusão-membrana, obteve-se o menor valor de Rd. Tanto o GCL quanto o CCL apresentaram comportamento membrana e geração de pressão osmótica para as soluções utilizadas. No entanto, com a solução de \'K POT.+\' as diferenças de pressão se mantiveram durante o ensaio, enquanto que no caso da solução de \'CU POT.+2\' a pressão induzida no corpo de prova do CCL e do GCL tem um pico e logo diminue até zero. O GCL teve um aumento na condutividade hidráulica, no ensaio de advecção, quando permeado com solução de \'CU POT.+2\'. Este comportamento é atribuído ao colapso da dupla camada difusa das partículas de argila. O CCL não apresentou este comportamento. Os resultados deste trabalho sugerem que o CCL da Fm. Corumbataí tem melhor desempenho como barreira que o GCL, nas condições de laboratório e para as soluções usadas. / In this research the behavior of a compacted clayey liner (CCL) of Corumbataí Fm. and a geosynthetic clay liner (GCL) containing \'NA\'-bentonite, was evaluated in presence of hydraulic and chemical gradients. Physical and mineralogical properties of the soils were determined and batch tests were executed to obtain the adsorption parameters of the Freundlich and Langmuir models. A laboratory apparatus was developed for assessment of the membrane behavior allowing determining the chemico-osmotic efficiency coefficient (\'ômega\') in diffusion-membrane test. The advection test was carried out with existent equipment in geotechnical department. Both tests were performed with single salt \'KCL\' and \'CU\'CL IND.2\' 2\'H IND.2\'O\' solutions. The measured value of the retardation factor (Rd) for the batch test is bigger than the Rd measured in advection test while in the diffusion-membrane test, the Rd obtained is the smallest. Both GCL and the CCL exhibit membrane behavior and they generate osmotic pressure with both solutions. However with \'KCL\' solution the difference of pressure are maintained during the test, while in the case of \'CU POT.+2\' solution the induced pressure across the specimen of CCL and GCL have a peak to after decrease to zero. The GCL had an increase in the hydraulic conductivity for a \'CU POT.+2\' solution in the advection test. This behavior is attributed to the collapse of the diffuse double layers of clay particles. The CCL did not exhibit this behavior. The results of this study suggest that the CCL of Corumbataí Fm. has a better performance as clay barrier tha the GCL, considering the solutions used and in the laboratory conditions.
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Transporte de solutos em barreiras de material argiloso compactado (CCL) e geocomposto bentonítico (GCL): fluxos diretos, acoplados e comportamento membrana / Solute transport through compacted clay liner (CCL) and geosynthetic clay liner (GCL): direct and coupled flux and membrane behavior

Laespiga, Marcos Andrés Musso 20 August 2008 (has links)
Neste trabalho foi analisado o comportamento de um solo argiloso compactado (CCL) da Fm. Corumbataí e de um geocomposto bentonítico (GCL) composto por bentonita \'NA\', frente a gradientes hidráulicos e químicos. As propriedades físicas e mineralógicas dos solos foram avaliadas, bem como determinados em ensaios de adsorção em lote os parâmetros das isotermas de Freundlich e Langmuir. Foi desenvolvido um equipamento para avaliar o comportamento membrana e poder calcular o coeficiente de eficiência químico-osmótico (\'ômega\') em ensaio de difusão-membrana. Os ensaios de advecção foram executados com o equipamento já existente no departamento de Geotecnia. Em todos os ensaios foram utilizadas soluções monoiônicas de \'KCL\' e \'CU\'CL IND.2\' 2\'H IND.2\'O\'. O valor do factor de retardamento Rd determinado no ensaio em lote (batch test) foi maior que o Rd medido no ensaio de advecção, enquanto que, no ensaio de difusão-membrana, obteve-se o menor valor de Rd. Tanto o GCL quanto o CCL apresentaram comportamento membrana e geração de pressão osmótica para as soluções utilizadas. No entanto, com a solução de \'K POT.+\' as diferenças de pressão se mantiveram durante o ensaio, enquanto que no caso da solução de \'CU POT.+2\' a pressão induzida no corpo de prova do CCL e do GCL tem um pico e logo diminue até zero. O GCL teve um aumento na condutividade hidráulica, no ensaio de advecção, quando permeado com solução de \'CU POT.+2\'. Este comportamento é atribuído ao colapso da dupla camada difusa das partículas de argila. O CCL não apresentou este comportamento. Os resultados deste trabalho sugerem que o CCL da Fm. Corumbataí tem melhor desempenho como barreira que o GCL, nas condições de laboratório e para as soluções usadas. / In this research the behavior of a compacted clayey liner (CCL) of Corumbataí Fm. and a geosynthetic clay liner (GCL) containing \'NA\'-bentonite, was evaluated in presence of hydraulic and chemical gradients. Physical and mineralogical properties of the soils were determined and batch tests were executed to obtain the adsorption parameters of the Freundlich and Langmuir models. A laboratory apparatus was developed for assessment of the membrane behavior allowing determining the chemico-osmotic efficiency coefficient (\'ômega\') in diffusion-membrane test. The advection test was carried out with existent equipment in geotechnical department. Both tests were performed with single salt \'KCL\' and \'CU\'CL IND.2\' 2\'H IND.2\'O\' solutions. The measured value of the retardation factor (Rd) for the batch test is bigger than the Rd measured in advection test while in the diffusion-membrane test, the Rd obtained is the smallest. Both GCL and the CCL exhibit membrane behavior and they generate osmotic pressure with both solutions. However with \'KCL\' solution the difference of pressure are maintained during the test, while in the case of \'CU POT.+2\' solution the induced pressure across the specimen of CCL and GCL have a peak to after decrease to zero. The GCL had an increase in the hydraulic conductivity for a \'CU POT.+2\' solution in the advection test. This behavior is attributed to the collapse of the diffuse double layers of clay particles. The CCL did not exhibit this behavior. The results of this study suggest that the CCL of Corumbataí Fm. has a better performance as clay barrier tha the GCL, considering the solutions used and in the laboratory conditions.

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