• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1153
  • 818
  • 181
  • 129
  • 114
  • 76
  • 39
  • 30
  • 26
  • 20
  • 18
  • 13
  • 10
  • 9
  • 9
  • Tagged with
  • 2986
  • 923
  • 345
  • 277
  • 271
  • 226
  • 154
  • 152
  • 139
  • 137
  • 133
  • 123
  • 121
  • 113
  • 106
  • 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

Patch test analysis using horizontal cross section of an underwater feature for multibeam echo sounding system

Kao, I-chieh 09 February 2009 (has links)
Multibeam system is a rather new technique for generating huge digital terrain model quickly. If the primitive data does not perform quality control and the calibration process, inconsistency among the axes of transducer, motion sensor and gyrocompass may results in unreasonable underwater topography. The problem in the hydrographic surveying in the practice is not easy to seek for the suitable seabed or underwater feature for patch test at present. This research attempts to use fewer horizontal cross section of an underwater feature to compute roll, pitch and yaw deviation angle that differs from traditional vertical profile computing approach for patch test. And using different survey line combination and different underwater topography condition to achieve independent solution of angle deviation . We also design the new processing order for patch test. It hopes to utilize this concept to carry out patch test by the common underwater feature or recycling man-made object for resolving this problem in the future. The experimental results show that new calibration can get the same achievement as the traditional calibration by the CARIS HIPS software, and the calibration results applied in the cross check lines can pass through IHO special standard. It shows that the calibration results not only suit for calibration survey lines, but also good for rest of the area. It proves the proposed new patch test is feasible.
2

An investigation into improving weld strengths during spot welding

Arumugam, Aravinthan January 2003 (has links)
Spot welding is a process that is widely used in industries worldwide. This project aims to research and develop a control system to improve the strengths of the spot welds. Conventional (pneumatic) spot welding systems do not lend themselves towards in-process control specifically controlling the forging force during welding. The importance of the forging force is that it is related to the dynamic resistance and hence to the rate of heating of the weld as has been shown in this work. The use of the forging force to control weld strengths was investigated by converting the electrode actuating system of a pneumatic spot welder to a motor driven servo system. This enabled the electrode forging force to be varied during welding. The control system was used to vary the forging force during welding by means of various preset force profiles in order to vary the heating during welding. The effects of the various force profiles to heat generation and weld growth were studied by using the dynamic resistance curve. The relationship between resistance and force enables the dynamic resistance to be used as an indicator for weld performance. Experiments were carried out to propose the force profile that will give the highest weld strength. Results obtained from this project shows that two changes in the characteristics of the force profile, viz, the delay time before ramping and the rate of ramping, affects the amount of heat supplied to the weld during welding which causes change in the weld strength. Statistically significant differences between average weld strengths due to the changes in these characteristics are presented. Forging force control was also found to produce stronger welds compared to the conventional electrode clamping force (ECF) condition, which was found to be statistically significant. It was also found possible to extend the weld lobe region of the electrode clamping force (ECF) condition by using forging force control, to produce improved weld strengths at the no weld and expulsion regions of the lobe. The profile that starts with a lower force and ends with a higher force with a longer ramping delay and slower ramping rate was the profile that produces the strongest weld strength among all the profiles tested. This profile with a welding current below the expulsion limit was suggested as the strategy to produce stronger welds at a faster rate.
3

The development of a clinical tool to measure handicap in rheumatoid arthritis

Carr, Alison Jane January 1996 (has links)
No description available.
4

Law, order and representation : the search for justice in a media age

Holohan, Siobhan January 2002 (has links)
No description available.
5

A numerical model for shore-normal sediment size variation (with particular reference to the north coast of the Isle of Man)

Horn, Diane Patricia January 1991 (has links)
No description available.
6

Elucidating the chemical and thermal unfolding profiles of organophosphorus hydrolase and increasing its operational stability

Armstrong, Charles David 15 May 2009 (has links)
Organophosphorus hydrolase (OPH, EC 3.1.8.1) is a homodimeric enzyme that has been observed to unfold via a three-state unfolding pathway (N2* ↔ I2 ↔ 2U) under chemical denaturing conditions. The dimeric intermediate (I2) is catalytically inactive and, although this enzyme has a very large overall conformational stability (~40 kcal/mol), it takes only a small amount of energy (~4 kcal/mol) to unfold this enzyme into its inactive form. So that this enzyme might be engineered as a more effective tool for nerve agent countermeasures and bioremediation purposes, its operational stability (the energy required to unfold the enzyme from its active, dimeric state to its inactive, dimeric state) must be increased. For this purpose, it is necessary to understand how the enzyme unfolds into its inactive, intermediate state. As tryptophan residues are sensitive probes of the microenvironment surrounding the residue, enzyme variants consisting of one tryptophan per subunit were constructed. Unfortunately, these variant enzymes did not fold into active conformations, and so could not be used to develop an accurate unfolding profile for the wild type enzyme. Limited proteolysis of OPH by thermolysin revealed detailed information on the unfolding process of OPH in chemical and thermal denaturing conditions. Mild denaturing conditions induced an initial enhancement of activity with a subsequent loss of catalytic activity upon more aggressive treatment. Under thermal conditions from 35 – 55 °C, the enzyme developed a well populated and active intermediate that displayed maximal activity. Similarly, the enzyme displayed maximal activity when incubated at 1.0 M urea. The regions of the enzyme, which became accessible to proteolysis at 45 °C and 1 M urea, were identical. This suggested that increased flexibility of these regions was coupled with the increase in the enzyme’s catalytic activity. Two regions that were determined by limited proteolysis to be the first to unfold were bridged with a novel disulfide bond. The result was an enzyme with an increased operational stability and resistance to proteolysis. This enzyme retained approximately 70% of its original activity in 8 M urea while no activity remained for the wild type enzyme when incubated in 6.5 M urea.
7

Improvement in the performance of VDSL2 Modem

Wu, Chang-Jui 22 January 2008 (has links)
VDSL2 is the fastest xDSL technology at present. Its data rate is variable depending on the length of wire and generally higher than HDSL and VDSL. VDSL2 uses the original POTS hardware to provide up to 100 Mbps data rate in upstream and downstream. The disadvantage of VDSL2 is that the longer the transmission distance, the lower the data rate. Generally speaking, the transmission distance is typically less than 1200 meters. The VDSL2 modem in this research is based on Infineon chip set composed of PEB83000 and ADM5120 with an operating band up to 30 MHz. The data rate in the different profiles of chip set is compared to find the optimum performance for a certain transmission distance.
8

A profile of horse riding injuries in adult horse riders registered with the Kwa Zulu Natal Horse Society

Catlin, Jo-Anne Carrie January 2010 (has links)
Dissertation submitted in partial compliance with the requirements for a Masters Degree in Technology: Chiropractic, Durban University of Technology, 2010. / Introduction: Equestrian sport as a competitive sport first began in 1868 at the Royal Dublin Horse Show 1. Injuries, especially minor injuries, are seldom reported, and there are no regulatory requirements anywhere that compel formal injury notification of this sport 2. Objectives: The objectives were to describe a profile of horse riding injuries, to determine the association between the type of equestrian activity and location and mechanism of injury, the association between use and type of equipment and location of injury and to determine anthropometric and history variables associated with location of horse riding injuries. As well as determining if non riding related injuries were associated with riding related injuries in the same sites. Therefore, for the purpose of this study, the following information was gathered in order to build up an injury profile: Anthropometric values (age, height, weight, gender, ethnicity, dominant hand and medical aid) of competitive horse riders in KwaZulu-Natal, South Africa, The participants horse riding history, Their record of any past or current injuries, Factors associated with previous and current injuries were also investigated, Equipment and facilities used Methods: This study was a quantitative descriptive design, which was questionnaire based and was administered by the researcher at various competitions in KwaZulu Natal or sent via email to those not present at the competitions. The study was limited to adult members of the KwaZulu Natal Horse Society that competed in on the Olympic disciplines of dressage, show jumping and eventing. iv Results: There were 176 respondents to the study. The average age was 36.3 years. The vast majority of participants were White (99.4%) females (81%). The overall prevalence of injury was 90.3%. Muscle strains were the most common type of injury. The head was the most commonly injured site (46.4%), the lower back was the site most likely to be injured many times. Forceful falls were ranked as the most severe type of injury mechanism. Most injuries occurred whilst jumping (63.8%). Use of protective equipment was associated with injury prevention and protection. Muscle strains due to riding were significantly less common in those who presently did regular exercise. Having no medical problems was associated with not having any riding injuries. There was no significant association between riding and non riding related injuries.
9

Population change and socio-economic development in Zimbabwe

Zanamwe, Lazarus January 1989 (has links)
It is a commonly held theory that population is related to levels of social and economic development within a given country or society. The work of Becker in the early 1960s gave much impetus to studies of the relationship between fertility, mortality and migration, on the one hand and their determinants, on the other. The determinants were seen as the social, economic, political and cultural settings of the countries or socities under study. The thesis attempts to apply this theory in relation to the demographic development of Zimbabwe. The thesis postulates that socio-economic differentials within Zimbabwe are sufficiently pronounced as to begin to affect the demographic structure of the country. It is with this in mind that three objectives are set for the thesis: a) the exploration of the demographic structure of the population of Zimbabwe, as a means of furthering the understanding of the nature of the demographic development of the country; b) the development and utilization of data estimation techniques as a means of overcoming the deficiencies in the data collected from official sources; and, c) the investigation of the link between population change, on the one hand, with social and economic development on the other. The hypothesis proceeds through the examination of such social and economic variables as income, education, health and other social indicators in relation to fertility, migration and mortality. Due to the inadequacy of data on the demographic variables, the thesis estimates such data using the recognized relationships among the demographic variables. The estimated demographic measures are subjected to correlation and regression analysis after the development structure of the country has been explored through factor and cluster analysis. Three geographical scales are used in the analyses viz. the province, the district and the local authority area. Use of the three geographical scales exposes the dangers of extrapolating and generalizing national patterns of demographic, social and economic development to the levels of the district and the local authority, as well as exposing different features of the development profile of the country of Zimbabwe. The thesis concludes that there is a differentiation in the demographic profile of the various geographical regions of the country, based on inequitable distribution of resources in the past when the country was under white settler colonial rule. The advent of independence and the introduction of policies designed to reduce such inequalities had not had time to work by the time the 1982 Census, from whose data the study is based, was taken. The thesis therefore recommends that further censuses are required if the effect of such policies are to be measured. It further recommends the use of cross-temporal instead of the cross-sectional data which was applied in this study.
10

Dissolution Study of Investigational Tablet of 5mg Oxycodone HCl/25mg Dextromethorphan HBr to Determine a Release Profile

Martinez, David January 2005 (has links)
Class of 2005 Abstract / Objectives: To standardize six tablets that share a statistically insignificant in vitro dissolution profile consisting of an experimental mixture of oxycodone HCl paired with dextromethorphan. We wanted to see if the release dynamics were not statistically different in an aqueous environment utilizing testing via USP Apparatus II (rotating paddles) in order to establish a drug release profile. Methods: Six experimental formulation tablets of oxycodone/DM were placed in separate dissolution vessels. The medium contained 900ml of water (standard media per USP) at 37°C (standard temperature per USP). Samples were taken at the 1, 2, 4, 6, 8, and 24 hour time periods and quantified using HPLC. The aim of this experiment was not meant to simulate an in vivo environment but simply to gain preliminary data for future research. Results: A one-sample t-test was used to calculate significant differences between the release profiles of oxycodone and dextromethorphan. We found that the release of all 6 tablets were not significantly statistically different for active ingredients, oxycodone and dextromethorphan. This data validated our hypothesis that the six experimental tablets would release the active ingredients over a 24-hour period at very similar and statistically insignificant rates. Implications: We now have a tablet formulation that can be replicated and used for further research including animal studies, and possibly human clinical trials, in order to develop a new pharmacotherapeutic approach for pain management.

Page generated in 0.0986 seconds