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Correlation between Laboratory Test Scores and Practical Test Scores in Driver Education and TrainingPertuit, Ted L. 08 1900 (has links)
The problem of this thesis is to determine the degree of relationship existing between laboratory test scores and practical test scores in driver education and training. The tests considered in this study are depth perception, visual acuity, reaction time, and field of vision.
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[pt] AVALIAÇÃO EM LABORATÓRIO DO TRANSPORTE DE CONTAMINANTES NO SOLO DO ATERRO SANITÁRIO DE SAUÍPE/BA / [en] LABORATORY ASSEISMENT OF SOIL CONTAMINANT TRANSPORT IN SAUIPE MUNICIPAL WASTE LANDFILLPEDRO OLIVEIRA DA SILVA COSTA 09 September 2002 (has links)
[pt] Este trabalho tem como objetivo apresentar uma avaliação da mobilidade do chorume no solo do aterro Sanitário de Sauípe, no município de Entre Rios, BA. O estudo se baseia em resultados de ensaios de laboratório e em dados encontrados na literatura, os quais foram utilizados para prever o transporte do contaminante e os principais mecanismos de interação entre este e o solo. Foi utilizado um equipamento desenvolvido para a realização de ensaios de transporte em laboratório, que permite a determinação dos
parâmetros de transporte do contaminante no solo. / [en] The purpose of this thesis is to present an evaluation of
the mobility of leachate in the soil of Sauípe s Sanitary
Landfill, located in the municipality of Entre Rios, in the
State of Bahia. The study is based on experimental
laboratory results and on literature data, which
have been used for predicting the contaminant transport and
the main mechanisms of its interaction with the soil.
To carry out the laboratory tests has been used an
equipment developed for this purpose, which allows the
determination of the transport parameters of the
contaminant in the soil.
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Comparison Of Compressive Strength Test Procedures For Blended CementsUlker, 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.
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Building a framework for predicting the settlements of shallow foundations on granular soils using dynamically measured soil propertiesKacar, 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
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Προστασία γεωμεμβρανών με γεωυφάσματα: αποτελέσματα και συσχετίσεις κατά ΕΝ 13719Κονδύλη, 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.
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Προστασία Γεωμεμβρανών με Γεωυφάσματα: διερεύνηση συνθηκών ελέγχου κατά ΕΝ 13719Μπλαντζούκας, 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.
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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
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[en] USE OF VACUUM IN ONE DIMENSIONAL AND ISOTROPIC TESTS CARRIED OUT IN REMOULDED MATERIAL / [pt] UTILIZAÇÃO DE VÁCUO EM LABORATÓRIO PARA ENSAIOS DE ADENSAMENTO COM CARREGAMENTO UNIDIMENSIONAL E ISOTRÓPICO PARA MATERIAL REMOLDADOMARIO ROLANDO BONILLA CORREA 24 September 2024 (has links)
[pt] A técnica de melhoramento de solos moles com carregamento com
vácuo é uma técnica que a cada dia está sendo mais usada em diferentes
lugares do mundo, por oferecer, para alguns projetos, uma série de
vantagens em relação a outras técnicas de melhoramento de solos moles.
Os ensaios de laboratório constituem-se em uma fonte de informações
fundamental para um projeto de melhoramento de solos moles. No
presente trabalho é feito um estudo experimental para usar vácuo em
laboratório, para ensaios de adensamento com carregamento
unidimensional (convencional, na prensa tipo Bishop) e com carregamento
isotrópico (na célula triaxial), usando material remoldado. Para isto, foi
fundamental desenvolver procedimentos para a execução de cada um
desses ensaios. Apresentaram-se vaias dificuldades para levar a pressão
de vácuo até o corpo de prova, para evitar perdas de pressão, para manter
constante a pressão durante todo o ensaio e outras mais. Foi necessário
testar diferentes técnicas para superar as dificuldades, até obter um
funcionamento satisfatório. Com os procedimentos desenvolvidos foi
realizada uma campanha de ensaios para conhecer os resultados que
estes ensaios fornecem. Com os resultados obtidos foram feitas análises
para sua interpretação. Comprovou-se experimentalmente que o vácuo
trabalha como um carregamento para adensamento de solos moles. / [en] The technique of improve soft soils with vacuum consolidation, is a technique that is more and more used, in different places of the world, because it offer a series of advantages in relation with others techniques of improve soft soils, depending of the kind of project. The laboratory tests are important fonts of information for projects of improve soft soils. This work isan experimental study for use vacuum in laboratory, for consolidation tests with one-dimensional load (conventional, in the Bishop s press) and with isotropic load (in the triaxial cell), using remolded material. For make this,was fundamental the development of procedure for the execution of eachtests. Various difficulties happened during this development, this situationforced to test different techniques until to obtain a satisfactory operation.With the development of the procedures was done a series of tests forknow the results, that these tests provide. With the results obtained weredone analyses for its interpretation.
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Dynamic Vehicle-Track Interaction of European Standard Freight Wagons with Link SuspensionJönsson, 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
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Prediction Of Geotechnical Properties Of Cohesive Soils From In-situ Tests: An Evaluation Of A Local DatabaseYaman, 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 & / 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.
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