The objective of this study was two-fold: 1) to determine the accuracy of the Elements Apex Locator and 2) to compare the accuracy of the alginate and Endo Q models as in-vitro apex locator testing devices. Twenty teeth were decoronated at the CEJ and triplicate measurements were made using the Elements Apex Locator. All measurements were made to the apex reading of the apex locator. True length was established by visualizing the file tip at the apex with a dental operating microscope. Measurements were then taken with the teeth mounted in an alginate model and then in the Endo Q model. The two models were compared using a repeated-measure ANOVA. Statistically significant differences occurred between the alginate and Endo Q models. The results showed that in 95% (n=19) of the cases, an accurate location to within + 0.5 mm of the apical foramen was obtained with the Endo Q model and 55% (n=11) with the alginate model. With a + 1.0 mm tolerance level, an accuracy of 95% (n=19) was found with the use of the alginate model. In conclusion, it seems that the Endo Q system was more suitable for testing the electronic apex locator than the alginate model. The Elements Apex Locator with the use of the Endo Q model was highly accurate in locating to within + 0.5 mm of the apical foramen (Mean deviation = .17 mm).

"This thesis describes a co-processor system that has been designed to accelerate computations associated with Singular Value Array Reconciliation Tomography (SART), a method for locating a wide-band RF source which may be positioned within an indoor environment, where RF propagation characteristics make source localization very challenging. The co-processor system is based on field programmable gate array (FPGA) technology, which offers a low-cost alternative to customized integrated circuits, while still providing the high performance, low power, and small size associated with a custom integrated solution. The system has been developed in VHDL, and implemented on a Virtex-4 SX55 FPGA development platform. The system is easy to use, and may be accessed through a C program or MATLAB script. Compared to a Pentium 4 CPU running at 3 GHz, use of the co-processor system provides a speed-up of about 6 times for the current signal matrix size of 128-by-16. Greater speed-ups may be obtained by using multiple devices in parallel. The system is capable of computing the SART metric to an accuracy of about -145 dB with respect to its true value. This level of accuracy, which is shown to be better than that obtained using single precision floating point arithmetic, allows even relatively weak signals to make a meaningful contribution to the final SART solution."

The aim of this study was to determine the change in working length (∆WL) before and after coronal flaring and after complete rotary instrumentation as a function of canal curvature. One mesiobuccal or mesiolingual canal from each of 43 extracted molars had coronal standardization and access performed. Once the access was completed, canal preparation was accomplished using Gates Glidden drills for coronal flaring and EndoSequence files for rotary instrumentation. WLs were obtained at 3 time points: pre-instrumentation (unflared), mid-instrumentation (flared) and post-instrumentation (concluded). Measurements were made via direct visualization (DV) and the CanalPro apex locator (EM) in triplicate by a single operator with blinding across the time points. Root curvature was measured using Schneider’s technique. The change in working length was assessed using repeated-measures ANCOVA. The direct visualization measurements were statistically larger than the electronic measurements (paired t-test difference = 0.20 mm, SE = 0.037, P < .0001), although a difference this large may not be clinically important. Overall, a greater change in working length was observed in straight canals than in curved canals. This unexpected finding was attributed to the limitations of the study, specifically the confounding factor of root length. This trend was more pronounced when measured electronically than via direct visualization, especially after complete instrumentation than after coronal flaring. The overall change in working length after complete instrumentation was found to be clinically insignificant in this study. A limited amount of change in working length may be expected prior to obturation.

<p>In this bachelor thesis, cable fault locators are studied for use on the overhead electrode lines in the HVDC (High Voltage Direct Current) Light project Caprivi Link. The cable fault locators studied operates with the principle of travelling waves, where a pulse is sent in the tested conductor. The time difference is measured from the injection moment to the reflection is received. If the propagation speed of the pulse is known the distance to the fault can be calculated. This type of unit is typically referred to as a TDR (Time Domain Reflectometer). The study is performed as a computer simulation where a simplified model of a TDR unit is created and applied to an electrode line model by using PSCAD/EMTDC. Staged faults of open circuit and ground fault types are placed at three distances on the electrode line model, different parameters of the TDR units such as pulse width and pulse amplitude along with its connection to the electrode line are then studied and evaluated. The results of the simulations show that it is possible to detect faults of both open circuit and ground fault types with a suitable TDR unit. Ground faults with high resistance occurring at long distances can be hard to detect due to low reflection amplitudes from the injections. This problem can somewhat be resolved with a function that lets the user compare an old trace of a “healthy” line with the new trace. The study shows that most of the faults can be detected and a distance to the fault can be calculated within an accuracy of ± 250 m. The pulse width of the TDR needs to be at least 10 μs, preferable 20 μs to deliver high enough energy to the fault to create a detectable reflection. The pulse amplitude seams to be of less significance in this simulation, although higher pulse amplitude is likely to be more suitable in a real measurement due to the higher energy delivered to the fault. The Hipotronics TDR 1150 is a unit that fulfil these requirements and should therefore be able to work as a line fault locator on the electrode line.</p>

Transmission lines of any voltage level are subject to faults. To speed up repairs and restoration of power, it is important to know where the fault is located. A fault location algorithm’s result is influenced by a series of modeling equations, setting parameters and system factors reflected in voltage and current inputs. The factors mentioned are subject to sources of uncertainty including measurement and signal processing errors, setting errors and incomplete modeling of a system under fault conditions. These errors have affected the accuracy of the distance to fault calculation. Accurate fault location reduces operating costs by avoiding lengthy and expensive patrols. Accurate fault location speeds up repairs and restoration of lines, ultimately reducing revenue loss caused by outages. In this thesis, we have reviewed the fault location algorithms and also how the uncertainty affects the results of fault location. Sensitivity analysis is able to analyze how the variation in the output of the fault location algorithms can be allocated to the variation of uncertain factors. In this research, we have used global sensitivity analysis to determine the most contributed uncertain factors and also the interaction of the uncertain factors. We have chosen Analysis of Variance (ANOVA) decomposition as our global sensitivity analysis. ANOVA decomposition shows us the insight of the fault location, such as relations between uncertain factors of the fault location. Quasi regression technique has also been used to approximate a function. In this research, the transmission line fault location system is fitted into the ANOVA decomposition using quasi regression. From the approximate function, we are able to get the variance of the sensitivity of fault location to uncertain factors using Monte Carlo method. In this research, we have designed novel methodology to test the fault location algorithms and compare the fault location algorithms. In practice, such analysis not only helps in selecting the optimal locator for a specific application, it also helps in the calibration process. / Thesis (M.Eng.Sc.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2009

This work is focused on the locating of faults of the cables laid in the ground. Firstly it describes particular types of cables and their basic physical characteristics. Following part deals with widely used methods for locating cable faults including their comparison. Than it describes DC measurements which are used to identify the type of fault. In the practical part there is a complete DC measurement on the specific cable and finding out the limits of usefulness regarding to the chosen methods for locating the failures.

Society is increasingly concerned about the environmental impact of energy systems, and prefers to locate power lines underground. In future, certain socially/environmentally sensitive overhead transmission feeders will need to include underground cable sections. Fault location, especially when using travelling waves, become complicated when the combined transmission line includes a number of discontinuities, such as junction points, teed points and fault points. Consequently, a diverse range of fault locators were developed in this thesis, and the performance of the proposed fault locators investigated. For a combined transmission line (CTL), consisting of one or more overhead line sections and one or more underground cable sections, a hybrid fault location scheme is proposed. This utilises the robustness of an impedance based distance algorithm and the accuracy, but stability concerns, of a travelling wave based fault locator, to determine the faulted section. The distance algorithm can determine the approximate fault location, but if the fault is located near an “underground-overhead” junction point, the accuracy is not sufficient to decide whether the fault is located on the overhead or the underground section. This thesis proposes utilizing a single end travelling wave fault locator to improve the accuracy of the fault location decision. The single end travelling wave fault locator can determine the fault section according to the permutation of the polarity of the “special surges”, which is especially important when the fault is close to a junction point. However, this single end fault locator fails in certain “blind” areas, wand these require the use of a distance relay to help determine fault section. Simulation results demonstrated that this hybrid fault locator can reliably determine which section of the feeder is faulty. For all types of CTL, including teed networks, the multiple-end travelling wave fault locator, utilising the arrival time at the feeder ends of the first fault instigated surges, can estimate the fault location. One of the main features of the proposed fault locator is the classification of the time difference between the arrivals of a fault instigated surge at the feeder ends as standard values, when the fault is located at each of the junction points or teed points. Comparing the time differences measured during an actual fault with these standard values allows the faulted feeder section to be estimated. The simulation results show this multiple-end travelling wave fault locator is highly reliable and suitable for application on combined overhead and underground transmission lines.

>Magister Scientiae - MSc / Aim: The aim of this study is to test and compare the retentive properties of two types of attachments i.e. Locator® and OT equator in a mandibular overdenture placed over 2 implants.

El objetivo del presente trabajo es demostrar la viabilidad de un negocio orientado al rastreo satelital de mascotas a través de un microchip insertado en los canes, el cual se encuentra ligado a un aplicativo móvil que ofrece servicios adicionales como la ubicación de veterinarias y pet shops aledaños, así como un historial de paseadores de perros calificados. Para ello, se detalla el planeamiento estratégico que incluye un análisis interno y externo de la organización. Asimismo, se explican los resultados de la investigación de mercado. También, se precisan los planes de marketing, operaciones, económico-financiero y la estructura organizacional, junto con la gestión de recursos humanos. En la investigación, se utiliza tanto la metodología cualitativa como la cuantitativa. Los resultados indican la viabilidad del negocio, así como su aceptación por parte del público objetivo y su rentabilidad para los accionistas e inversionistas de la empresa. Se concluye, por lo tanto, que el modelo de negocio de GPS PETS es viable, alcanzable y expandible en el mercado peruano. / The aim of this project is to prove the viability of a business created to track pets through a microchip inserted in dogs, which is linked to a mobile application that also offers certain services such as the location of pet shops and vet centers nearby. It also contains a list of dog walkers who are highly qualified. Therefore, a strategic planning is listed, which includes an internal and external analysis of the organization. Plus, the results of the market research are explained in detail. Moreover, the marketing, economic, and operational plans are described along with the organizational structure and the human resources management. In this investigation, the quantitative and qualitative research methods are used. The results indicate the viability of this business, as well as its acceptance by the target market, and its profitability for the company’s shareholders and investors. To sum up, it is concluded that GPS PETS business model is achievable, sustainable and expandable in the Peruvian market. / Trabajo de investigación

This thesis gives an overview on the fault of high-voltage cable transmission lines in the distribution system of the E.ON company. The first part of this thesis introduces reader to the topic of cable transmission lines, types of commonly used cables and the most commonly occurring faults. In the second part of this thesis, the methods of locating faults in cable transmission lines by professional personnel are explained. The third part deals with the analysis of a group of chosen occurred faults. The final part focuses on the statistics of fault occurrence on South Moravian region from 1.1.2017 until 1.1.2019.