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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.
81

The relationship between the strength of the erector spinal muscles : and their EMG pattern of fatigue during various sustained postures

Gross, Ditza. January 1976 (has links)
No description available.
82

Some considerations of the shear strength of a fabric anisotropic soil

Liao, Chung-Lon. January 1979 (has links)
No description available.
83

Orthodontic shear bond strengths of a self-adhering resin to enamel, restorative composite and porcelain

Bernas, Andrew J. 25 July 2013 (has links)
As new adhesive products become available in restorative dentistry, investigating their potential application for orthodontic use is warranted. Vertise Flow (Kerr) is a self-adhering flowable resin and is being marketed for use as a sealant, porcelain repair and small class I restorations. It has potential for use as an orthodontic adhesive. Objective: Determine if Vertise Flow (Kerr) is suitable for bonding fixed orthodontic appliances to enamel, restorative resin composite and porcelain with minimal surface preparation. Methods: Shear Bond Strengths (SBS) from six (6) groups of fifteen (15) bonded stainless steel lingual buttons (Ormco) were obtained over three time points (24hr, 7 days, and 3 months). The six test groups were: 1.Vertise Flow to enamel (Tt) with coarse pumice debridement, 2. Transbond XT (3M, Unitek) to enamel (Tc) with phosphoric acid etching [control], 3.Vertise Flow to Herculite Ultra (Kerr) (Cc) with coarse pumice debridement, 4. Vertise Flow to Filtek Supreme Ultra (3M, ESPE) (Ct) with coarse pumice debridement, 5. Vertise Flow (Kerr) to porcelain (Pt) with diamond bur roughening, and 6. Transbond XT (3M Unitek) to porcelain (Pc) with hydrofluoric acid etching. Samples were stored in distilled water and incubated at 37C. The buttons were then debonded with a Zwick Universal Testing machine using a 10 kN load cell with a crosshead speed of 0.5mm/min. Debonded buttons were evaluated based on a modified Adhesive Remnant Index (ARI). Statistical assessment of the data was performed using parametric and non-parametric tests, with p<0.05 as the threshold for statistical significance. Results: The mean SBS obtained in all groups at each time point were >4MPa and varied between 8.69MPa and 27.44MPa. Statistical differences were found within the composite and porcelain groups at T1, and the enamel and composite groups at both T2 and T3. Nearly half of the sample (47.2%) achieved an ARI score of 5 (100% adhesive left on button base). Conclusion: Vertise Flow potentially provides clinically acceptable bond strengths to enamel, restorative resin composite and porcelain with minimal surface preparation. Furthermore, upon removal, minimal adhesive clean-up is required thus saving valuable chair time. Based on the results in this study, future in vivo investigation is suggested.
84

Mobility in older adults

Webber, Sandra 12 April 2010 (has links)
Mobility plays an important role in determining quality of life in older adults as it is closely tied to health, participation, and independence in later years. Although much of the literature to date has focused on walking and stair climbing, mobility also encompasses driving and the use of public transportation to access the community. Comprehensive definitions of mobility and techniques for objectively measuring community mobility are generally lacking. This thesis describes a new theoretical framework for mobility that illustrates how impairments can lead to limitations in accessing different life-spaces, and stresses the associations among determinants that influence mobility. The feasibility of using global positioning system (GPS) watches and accelerometers to monitor community mobility in older adults was also examined. Data acquired from the equipment were quite variable. While the technology offers promise for capturing detailed information (e.g., the timing, distances covered, and speeds reached on foot and in-vehicle), new GPS solutions are required to allow for data collection over an extended period of time. In addition, projects were conducted to examine ankle strength and power in older women because these muscle groups are important for physical function and mobility. Test-retest reliability on the dynamometer was found to be generally good for isotonic and isokinetic tests, but relatively poor for isometric rate of torque development. Measures of dorsiflexion (DF) and plantar flexion (PF) strength and power-related variables were significantly correlated with functional performance (gait speed, stair climb power, and foot movement time). An intervention study was conducted to determine the effects of ankle DF and PF resistance training performed concentrically “as fast as possible” on movement time in a brake response task. Power training with elastic bands resulted in the greatest reduction in movement time, which suggests that this low-cost, practical form of exercise may benefit older adults in circumstances when rapid generation of ankle torque is required. This thesis adds to the literature by examining mobility from a number of perspectives. Mobility determinants are comprehensively defined, community and laboratory-based measures are examined, and the effects of an intervention are evaluated to improve mobility assessment and treatment techniques in older adults.
85

The effect of crosshead speed, load cell configuration and curing time on the shear bond strength of orthodontic brackets

Cheba, Vivek 09 August 2012 (has links)
Objective: Evaluate the effect of crosshead speed, load cell configuration and curing time on shear bond strengths. Methods: 160 human molars were divided into equal groups of 20 second and 40 second photopolymerization times and then into 1kN or 10kN load cell groups. Each of the groups were divided into 0.5mm/min or 5mm/min crosshead speeds. Results: Regarding photopolymerization time (20s vs. 40s) and crosshead speeds (0.5mm/min vs. 5.0mm/min) there were no significant differences in SBS (p>0.05). The load cell configuration (1kN vs. 10kN) however showed statistically significant differences (p<0.05) with the 1kN producing higher bond strengths.
86

On the determination of the failure surfaces for an orthotropic quasi-homogeneous material

Kaminski, Benjamin Eugene 08 1900 (has links)
No description available.
87

The effect of controlling welding procedure and peening on the physical properties and transition constituents of the materials

Harrelson, Ottis Miles 08 1900 (has links)
No description available.
88

An investigation of the strength of rock

Schwartz, Arnold Edward 05 1900 (has links)
No description available.
89

Alternating method applied to 3-D part-through crack problems, with application to the weight function method

Liao, Cheng-Young 12 1900 (has links)
No description available.
90

The effect of debond growth on crack propagation in composite plates reinforced with adhesively bonded composite stringers

Bigelow, Catherine Ann 12 1900 (has links)
No description available.

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