• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 947
  • 198
  • 175
  • 161
  • 99
  • 56
  • 50
  • 26
  • 21
  • 18
  • 17
  • 17
  • 11
  • 11
  • 9
  • Tagged with
  • 2159
  • 400
  • 367
  • 240
  • 200
  • 183
  • 174
  • 136
  • 131
  • 123
  • 116
  • 108
  • 104
  • 101
  • 101
  • 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.
1

Experimental investigations of anchorage capacity of precast concrete bridge barrier for Performance Level 2

Ngan, Caroline Lai Yung 11 1900 (has links)
In the last twenty years, the design requirements of bridge barriers have changed with the aim of improving the safety of commuters on the bridge. A majority of precast concrete bridge barriers (PCBB) on highway bridges in British Columbia were designed and installed in accordance with the 1988 Canadian Highway Bridge Design Code (CHBDC). To ensure that these barriers comply with the current code requirements, research and testing were deemed obligatory. In particular, the anchorage capacity of the parapet under the CHBDC design load warrants verification. A finite element model of the barrier was developed in ANSYS to study its structural response. Static testing of a set of barriers was carried out at the University of British Columbia to better understand the behaviour of the barrier. The experimental results were used to calibrate and verify the finite element model. Through the finite element model and experimental results, a simpler model has been developed in a formatted spreadsheet environment to allow better estimates of the anchorage capacity of different barrier designs. The model was scaled to a wider use for practicing engineers so to ease and improve the design of anchorages of precast concrete bridge barrier under Performance Level 2 loading in accordance with the Canadian Highway Bridge Design Code.
2

Experimental investigations of anchorage capacity of precast concrete bridge barrier for Performance Level 2

Ngan, Caroline Lai Yung 11 1900 (has links)
In the last twenty years, the design requirements of bridge barriers have changed with the aim of improving the safety of commuters on the bridge. A majority of precast concrete bridge barriers (PCBB) on highway bridges in British Columbia were designed and installed in accordance with the 1988 Canadian Highway Bridge Design Code (CHBDC). To ensure that these barriers comply with the current code requirements, research and testing were deemed obligatory. In particular, the anchorage capacity of the parapet under the CHBDC design load warrants verification. A finite element model of the barrier was developed in ANSYS to study its structural response. Static testing of a set of barriers was carried out at the University of British Columbia to better understand the behaviour of the barrier. The experimental results were used to calibrate and verify the finite element model. Through the finite element model and experimental results, a simpler model has been developed in a formatted spreadsheet environment to allow better estimates of the anchorage capacity of different barrier designs. The model was scaled to a wider use for practicing engineers so to ease and improve the design of anchorages of precast concrete bridge barrier under Performance Level 2 loading in accordance with the Canadian Highway Bridge Design Code.
3

Experimental investigations of anchorage capacity of precast concrete bridge barrier for Performance Level 2

Ngan, Caroline Lai Yung 11 1900 (has links)
In the last twenty years, the design requirements of bridge barriers have changed with the aim of improving the safety of commuters on the bridge. A majority of precast concrete bridge barriers (PCBB) on highway bridges in British Columbia were designed and installed in accordance with the 1988 Canadian Highway Bridge Design Code (CHBDC). To ensure that these barriers comply with the current code requirements, research and testing were deemed obligatory. In particular, the anchorage capacity of the parapet under the CHBDC design load warrants verification. A finite element model of the barrier was developed in ANSYS to study its structural response. Static testing of a set of barriers was carried out at the University of British Columbia to better understand the behaviour of the barrier. The experimental results were used to calibrate and verify the finite element model. Through the finite element model and experimental results, a simpler model has been developed in a formatted spreadsheet environment to allow better estimates of the anchorage capacity of different barrier designs. The model was scaled to a wider use for practicing engineers so to ease and improve the design of anchorages of precast concrete bridge barrier under Performance Level 2 loading in accordance with the Canadian Highway Bridge Design Code. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate
4

The Blood-brain barrier in normal and pathological conditions /

Zhu, Chunni. January 2001 (has links) (PDF)
Thesis (Ph.D.)--University of Adelaide, Dept. of Anatomical Sciences, 2002? / Bibliography: leaves 318-367.
5

Knowledge transfer in project-based environments : The barriers of knowledge transfer

Niu, Bingyu, Yan, Sisi January 2012 (has links)
Background: Nowadays, projects become the common way of working in manycompanies. Knowledge management is important for efficient project management.Knowledge transfer in project-based environments became an attractive and importanttopic for study. Various barriers and challenges will appear during the process ofknowledge transfer in projects. Lots of authors thought the barriers of knowledgetransfer in project are negative, while others mentioned that some barriers may havepositive aspects. We called these two kinds of barriers “positive barriers” and“negative barriers” in this thesis. Purpose: The purpose of this thesis is to understand knowledge transfer inproject-based environments. Specifically, we aim to explain that barriers ofknowledge transfer in projects can be both negative and positive. Method: Due to the special time period and activity limitation, we chose case studyto gain the empirical data. When choosing the sample, we used the conveniencesampling. The sample chosen is a project team in Ericsson of Linköping. The projectmanager we interviewed has worked in Ericsson since 2004 and with his presentproject team for four years. He has already done more than fifteen projects, so he hasenough experience in projects for our study. We combined both inductive anddeductive approach strategies to analyze our thesis. Result: This thesis has answered the questions in the part of specified questions andreached the thesis purpose. It has explained the notion of knowledge transfer inprojects and its related barriers. It interprets how both negative and positive barriersaffect knowledge transfer. Furthermore, this thesis points out some suggestions forimproving positive barriers and reducing negative barriers.
6

INVESTIGATION OF THE PROCESS OF INTERNAL PHOTOEMISSION IN PLATINUM SILICIDE SCHOTTKY BARRIER DIODES (DETECTOR, INFRARED).

MOONEY, JONATHAN MARTIN. January 1986 (has links)
In this work, the theory of internal photoemission is reviewed and extended for the special case of platinum silicide Schottky barrier infrared photodiodes. Vickers' model of hot-electron-mode photodetection is recast in terms of hot-holes, and the effects of carrier energy loss due to phonon collisions, as well as the depletion of the occupation of the emitting states due to emission are included. The optical absorption of the Schottky diodes is measured and used to relate the quantum efficiency of the diodes to the internal yield as calculated from the model. By including the effects of the carrier energy loss due to phonon collisions and the depletion of the occupation of the emitting states in the model, one can resolve previously unexplained anomalies in the photoresponse data (the shape of the Fowler plots, the absolute magnitude of the yield, and the difference between the optical and thermal barriers). Independent estimates are obtained for the mean-free-path between hot-hole/phonon, hot-hole/cold-electron, and hot-hole/imperfection collisions as well as the mean phonon energy, mean transmission coefficient across the Schottky barrier, and the Fermi energy. The model is found to be in excellent agreement with the experimental data for parameter values consistent with those reported in the literature. Some degree of correlation is found to exist between the one free variable for each diode and the processing used for that diode. Namely, the temperature of the substrate during deposition is correlated with the value of the mean-free-path between imperfection scattering events.
7

Running away from and coming into the building: analysis of the ordinance relating to mean of escape andbarrier free access and understanding the conservation issues involved

Cheung, Wing-yee, Megdalen, 張穎儀 January 2007 (has links)
published_or_final_version / Conservation / Master / Master of Science in Conservation
8

Measurement of the airborne sound insulation of traffic noise barriers using impulse response techniques

Bull, John Ivan January 2014 (has links)
This research thesis involves the measurement of the airborne sound insulation of road traffic noise barriers, with the goal of gaining a more in depth understanding of the factors that influence noise barrier performance. A measurement system is developed, based on EN 1793-6:2012, to quantify the airborne sound insulation of a noise barrier in situ. Validation testing is performed to ensure that the system meets the requirements of EN 1793-6:2012. MATLAB code is developed, incorporating all of the signal processing tasks into a single graphical user interface. The measurement system is then used to measure the airborne sound insulation of eight existing traffic noise barriers located around Auckland, New Zealand. The results from the Auckland field tests show that consistent single number ratings of airborne sound insulation can be achieved on different samples of the same noise barrier. The presence of air gaps and hidden defects will degrade the acoustic performance of a noise barrier, most significantly at the high frequencies. The comparison of single number ratings calculated with differing measurement frequency ranges is discussed, and some comments are made on the measurement standard itself.
9

Studies of gastric mucus and bicarbonate secretion in vitro

Keogh, Julian Patrick January 1989 (has links)
No description available.
10

Transformation of wave spectra on non-uniform currents in water of varying depth

Chae, Jang Won January 1983 (has links)
No description available.

Page generated in 0.0496 seconds