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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.
41

The instability of circuits employing short radio waves

Peterson, Lawrence Howard. January 1931 (has links)
Call number: LD2668 .T4 1931 P41
42

An introduction to a new concept: the dynamic stability of disks freely descending in a fluid media

Himes, Billy Lee. January 1960 (has links)
Call number: LD2668 .T4 1960 H48
43

Flow resistance in ploughed upland drains : narrow channels with uniform or composite roughness

Flintham, T. P. January 1988 (has links)
Ploughed upland drains are straight prismatic channels of low aspect ratio. The drains are either uniformly or compositely roughened. In compositely roughened drains the bed and side-walls are differentially roughened although each roughness type is homogeneous. Upland catchments, containing extensive ploughed drainage networks, are particularly prone to flash flooding and increased sediment yield. However, the basic hydraulic data necessary to route flow through the drainage network and improve the engineering design of stable drainage channels are currently unavailable. A logarithmic flow resistance equation is developed for low aspect ratio channels, where the effective Nikuradse equivalent grain size is known. Testing against field data indicates that the relationship successfully predicts the resistance to uniform flow through upland drains. The performance of eight composite roughness formulae to predict the mean velocity in differentially roughened channels is compared. The composite roughness equations involve dividing the cross-sectional flow area into a number of sub-areas. The different methods of cross-sectional area division are considered and their effect on mean velocity prediction examined. Preferences are indicated concerning composite roughness equations which predict the mean velocity in channels of simple cross-sectional shape. Empirical equations are derived to determine the mean bed and side-wall shear stresses in straight symmetrical trapezoidal and rectangular open channels, with uniform or composite roughness. The model proposed is appropriate for stable sub-critical and super-critical flows. The equations are based on data collected from laboratory channels and should be cautiously applied to larger scale channels. Using the mean shear stress model, a design procedure is proposed to improve drainage channel stability.
44

Development and evaluation of a core training programme in highly trained swimmers

Hibbs, Angela E. January 2011 (has links)
Core training is a popular technique for athletes and coaches concerned with improving sports performance. Achieving an appropriate level of muscular activation is a vital ingredient in a successful training programme. However, the evidence base with regard to the effectiveness of core training on improving an athlete’s core ability and resultant sporting performance is limited. This thesis aims to 1) develop a core training programme for highly trained swimmers and 2) evaluate its effect on sporting performance using the Medical Research Council (MRC) framework for developing complex interventions. The thesis outlines current theories and findings in both the clinical and sporting sectors regarding core stability and core strength training and also the MRC framework. It determines the most appropriate method of measuring muscular activation of the core muscles (EMG) and establishes the reliability of the technique for assessing different exercises. Key core muscles were found to produce significantly reliable (P < 0.05) measurements of below 25% CV and > 0.7 ICC values while performing MVIC and core training exercises. Subsequently, popular low and high threshold core training exercises were analysed and muscle activation levels of 1 - 110% MVIC were identified. A new training programme was developed and tested on a group of highly trained swimmers over 6 and 12 week training intervention periods. Significant improvements (P < 0.05) and a large likelihood of beneficial improvement during the performance tests were observed following 6 and 12 weeks of training (P < 0.05) along with significant reductions in muscle activation (%MVIC) during the performance tests and training exercises. Conclusions from the intervention studies are used to develop a theoretical model outlining how to structure an effective core training programme for highly trained athletes. It is proposed that this model could be used by coaches and athletes to help plan, conduct and evaluate their core training to maximise the potential benefits that core training could have on sporting performance.
45

Towards the understanding of the steady tilt phenomenon in semi-submersibles

Atlar, M. January 1986 (has links)
No description available.
46

Knowledge-based assessment and enhancement of voltage stability

朱太秀, Zhu, Tai-xiu. January 1996 (has links)
published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
47

Design of power system stabilizers based on modal and eigenvalue sensitivity analyses

謝志棠, Tse, Chi-tong. January 1990 (has links)
published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
48

Experimental investigation on the web stability of plate girders

黃家正, Wong, Ka-ching. January 1960 (has links)
published_or_final_version / Civil Engineering / Master / Master of Science in Engineering
49

Interaction between local and Euler buckling modes in thin-walled columns

Kandil, Kamel Sayed Ahmed January 1988 (has links)
No description available.
50

Ground deformation in the vicinity of a trench heading

Phillips, R. January 1986 (has links)
No description available.

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