ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / NASA's Remote Imaging System Acquisition (RISA) project has the goal of producing a single robust and space-efficient imaging system. This paper will show the progress of the current RISA project iteration, tasked with implementing a Inter-Integrated Circuit (I²C) communications controller on a radiation hardened Field Programmable Gate Array (FPGA), characterizing a liquid lens optical system, and adding a radiation hardened temperature sensor. The optical design focuses on small liquid lenses that can vary focal length with no moving parts. The chosen designs will allow this camera system to meet critical mission objectives and provide reliable service to NASA's astronauts.

One of the issues with multilateral wells is determining the contribution of each lateral to the total production that is measured at the surface. Also, if water is detected at the surface or if the multilateral well performance declines, then it is difficult to identify which lateral or laterals are causing the production decline. One way to estimate the contribution from each lateral is to run production Logging Tools (PLT). Unfortunately, PLT jobs are expensive, time-consuming, labor-intensive and involve operational risks. An alternative way to measure the production from each lateral is to use Distributed Temperature Sensing (DTS) technology. Recent advances in DTS technology enable measuring the temperature profile in horizontal wells with high precision and resolution. The changes in the temperature profile are successfully used to calculate the production profile in horizontal wells. In this research, we develop a computer program that uses a multilateral well model to calculate the pressure and temperature profile in the motherbore. The results help understand the temperature and pressure behaviors in multilateral wells that are crucial in designing and optimizing DTS installations. Also, this model can be coupled with an inversion model that can use the measured temperature and pressure profile to calculate the production from each lateral. Our model shows that changing the permeability or the water cut produced from one lateral results in a clear signature in the motherbore temperature profile that can be measured with DTS technology. However, varying the length of one of the lateral did not seem to impact the temperature profile in the motherbore. For future work, this research recommends developing a numerical reservoir model that would enable studying the effect of lateral inference and reservoir heterogeneity. Also recommended is developing an inversion model that can be used to validate our model using field data.

In recent years, wireline temperature profiling methods have evolved to offer new insight into fractured rock hydrogeology. An important advance in temperature logging makes use of boreholes temporarily sealed with flexible impervious fabric liners so that the water column is static and effects of cross-connection are eliminated. For this project a characterization technique was developed based on combining fibre optic distributed temperatures sensing (DTS) with active heating within boreholes sealed with underground liners. DTS systems provide a temperature profiling method that offers improved temporal resolution when compared with wireline trolling based techniques. The ability to collect temperature profiles rapidly in time can improve understanding of transient processes. In this study the advantage of a sealed borehole environment for temperature investigations is demonstrated. Evidence for identifying active groundwater flow under natural gradient conditions using DTS heat pulse testing is presented through a comparison with high resolution geologic logging and hydraulic datasets.

Distributed Temperature Sensing (DTS) has been used in a variety of different applications. Its ability to detect temperature fluctuations along fiber optic lines that stretch for several kilometers has made it a popular topic in various fields of science, engineering, and technology. From pre-fire detection to ecological monitoring, DTS has taken a vital role in scientific research. DTS uses the principle of backscattering by three different spectral components, e.g., Rayleigh scattering, Brillouin scattering, and Raman scattering. Although there have been various improvements to DTS, its slow response time and poor spatial resolution have been hard to overcome. Its repetition rate is low because the pulse must travel the distance of the fiber optic line and return to the detector to record the temperature change along the fiber. A spatial resolution of 7.4 cm with a response time as low as 1 second and a temperature resolution of the 0.196 ℃ is achieved from the current Raman-based DTS system. This research proves that high-spatial resolution can be obtained with the use of a Silicon Avalanche Photodetector with a 1 GHz bandwidth. / MS / Sensors have been used for a variety of purposes such as to measure temperature and strain. Recent literature suggests that distributed temperature sensing (DTS) is a unique approach to measure temperature. DTS allows continuous, real-time measurements along a fiber optic cable. My research focused on improving the DTS system. A high-resolution Raman-based DTS was developed by 1) enhancing its spatial resolution, 2) shortening response time, 3) improving temperature resolution, and 4) extending the sensing distance. By enhancing these parameters, it will provide a wide range of new possibilities to the field of optical fiber sensing.

Infiltration and inflow (I/I) are common problems in the foul sewer system. A method to detect I/I that is not commonly used in Sweden is DTS, Distributed Temperature Sensing. DTS is based on continuous measurements of temperature over a predetermined distance in the sewer system. The I/I is detected as temperature differences in the temperature data that is registered in the sewer system. The measurements often take place over a couple of weeks or months in the sewer system. The aim of this project was to review previous studies where DTS was used to detect I/I in foul sewers.  Data from a wastewater treatment plant in Umeå together with meteorological data were analysed to be able to visualize the problem of I/I and then suggest how DTS can be applied in Sweden. Both automated and visual analyses was performed to find if there were any relationships between wastewater temperature, wastewater flow and precipitation.   The outcome was that it is possible to apply DTS in the foul sewages to detect I/I. DTS seemed to be able to detect I/I in all types of sewage material, however it is dependent on that the I/I temperature differs from the temperature of the foul sewage water. It is an expensive technique but if it is meant to be used many times to analyse bigger areas it can be worth the costs. If larger areas are to be investigated, the costs for DTS and current methods are approximately the same.  At the wastewater treatment plant in Umeå, a slight relationship between wastewater temperature, wastewater flow and precipitation could be detected. The degree of dilution was calculated to 1,34 which means that about 25% of the sewage water is I/I. The conclusion from this was that I/I exists in the foul sewers in Umeå. The leakage points could not be located with this analysis. DTS could be a possible method to detect the leakage points of I/I in foul sewers. Unlike smoke tests, colouring and video-inspection of the sewers, DTS might be able to detect smaller leakage points. / Tillskottsvatten är ett vanligt problem i spillvattenledningsnätet. DTS, Distributed Temperature Sensing är en metod som inte är vanlig i Sverige för kontroll av spillvattenledningar. Tekniken bygger på kontinuerliga temperaturmätningar under en tidsperiod över en förutbestämd sträcka och registrerar temperaturavvikelser som kan uppstå i samband med inläckage av tillskottsvatten. Syftet med projektet var att granska tidigare utförda studier med DTS för att ta reda på hur tekniken kan användas för att lokalisera inläckage i spillvattenledningar. För att vidare illustrera problematiken med tillskottsvatten i spillvattennätet samt föreslå hur DTS kan appliceras i Sverige genomfördes en analys av mätdata på inkommande vatten till reningsverket på Ön, Umeå. Både visuella och automatiserade analyser genomfördes där tolkningar gjordes utifrån mätdata från reningsverket tillsammans med nederbörds- och lufttemperaturdata. En regressionsanalys genomfördes som automatiserad analys för att undersöka eventuella samband mellan spillvattentemperatur, spillvattenflöde och nederbörd. Projektet inleddes med en litteraturstudie där det utreddes hur DTS fungerar teoretiskt och praktiskt. Litteraturstudien visade att DTS är praktiskt möjligt att applicera i spillvattenledningsnätet för att leta inläckagepunkter för tillskottsvatten. Inläckage kan registreras som ökningar eller sänkningar i spillvattentemperaturen beroende på lufttemperaturen. Den är inte beroende av material på ledningarna men däremot är DTS beroende av att tillskottsvattnet är av annan temperatur än spillvattnet. Det är en dyr teknik men kan vara värt investeringskostnaderna om mätningar tänkt ske många gånger under längre perioder. Vid kontroll av större områden med hjälp av röktest kombinerat med färgning av vatten och filmning är kostnaderna ungefär de samma. Utifrån mätdatan från reningsverket och nederbördsdatan från Umeå universitet kunde vissa samband påvisas mellan spillvattentemperatur, spillvattenflöde och nederbörd. Ett visst samband kunde även urskiljas mellan spillvattentemperatur och spillvattenflöde. Utspädningsgraden av spillvattnet beräknades till 1,34 vilket innebär att cirka 25% av vattnet i spillvattenledningarna är tillskottsvatten. Slutsatsen som kunde dras utifrån detta var att tillskottsvatten existerar i spillvattenledningsnätet som leder till reningsverket på Ön i Umeå. Däremot kunde inga slutsatser dras för att säga var inläckage av tillskottsvatten sker. DTS skulle kunna appliceras i ledningsnäten för att undersöka närmare var inläckagepunkterna är och tillskillnad från rökning, färgning av vatten och filmning som används idag kan DTS sannolikt upptäcka fler typer av inläckage.

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Soil cover systems are an integral part of a mine reclamation program and are increasing in area. Knowledge of temperatures and thermal properties in the cover system provide important information regarding the energy balance, thermal regime, as well as preliminary insight into soil water content. Cover system temperatures and thermal properties are measured at a small number of vertically intensive profiles. Current methods do not provide any information as to the spatial variation of temperatures and thermal properties at scales other than the point scale. The objective of this study was to investigate the spatial scaling of thermal properties in reclamation cover systems. A distributed temperature sensing (DTS) system was installed in three cover systems of various textures and configurations. Semivariogram analysis demonstrated that on a 40 m slope consisting of mineral soil over sand (Site #1) soil temperatures did not exhibit any spatial structure, due to the presence of vegetation. A 100 m cover system comprised of a structureless sand (Site #2) was confirmed to be spatially uniform through semivariogram analysis. Semivariograms at Site #2 displayed secondary structure that corresponded to the 65 m plateau and 35 m slope. Site #3 consisted of a uniform peat and a 2% slope. Spatial structure was non-existent at Site #3 and was attributed to the unique thermal properties of peat that magnified the effect of microtopography on the surface energy balance. A method to estimate apparent thermal inertia (ATI) using DTS measurements at the soil surface was developed. Apparent thermal inertia was found to be less uncertain than the current standard apparent thermal diffusivity. The ATI method was determined to be the preferred method as it was related to soil water content and not prone to estimation errors due to imprecise depth measurement. The spatial scaling properties of a 236 m cover system (Site #3) were investigated using estimations of ATI. Measurements were taken every meter along the transect for bulk density, elevation, air-dried thermal conductivity and air-dried volumetric heat capacity. The dominant scale of variation in ATI was not related to physical or thermal properties, which tended towards the 3 m scale (bulk density and thermal conductivity) or the 108 m and field scale trend (elevation and volumetric heat capacity). The dominant scale of variation in ATI shifted between 30 m and the field scale trend and was related to water content as represented by the soil matric potential. A dry cover system tended to homogenize thermal property distribution, leading to a dominance of the 108 m and field scale trend. Wetter days led to a shift to the 30 m scale, with intermediate days showing a mix in scale dominance. Information on thermal property spatial scaling properties of cover systems can be used to optimally design monitoring systems that measure at the same scale as that which the cover is performing. Characterizing the spatial variability of the system will lead to better cover system designs and ultimately a more sustainable system.

abstract: Underground transmission cables in power systems are less likely to experience electrical faults, however, resulting outage times are much greater in the event that a failure does occur. Unlike overhead lines, underground cables are not self-healing from flashover events. The faulted section must be located and repaired before the line can be put back into service. Since this will often require excavation of the underground duct bank, the procedure to repair the faulted section is both costly and time consuming. These added complications are the prime motivators for developing accurate and reliable ratings for underground cable circuits. This work will review the methods by which power ratings, or ampacity, for underground cables are determined and then evaluate those ratings by making comparison with measured data taken from an underground 69 kV cable, which is part of the Salt River Project (SRP) power subtransmission system. The process of acquiring, installing, and commissioning the temperature monitoring system is covered in detail as well. The collected data are also used to evaluate typical assumptions made when determining underground cable ratings such as cable hot-spot location and ambient temperatures. Analysis results show that the commonly made assumption that the deepest portion of an underground power cable installation will be the hot-spot location does not always hold true. It is shown that distributed cable temperature measurements can be used to locate the proper line segment to be used for cable ampacity calculations. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2015

This master's thesis deals with wireless sensor network and temperature sensors with aim to design and implement remote temperature sensing central based on mesh topology. This paper discuss components of board modules, their function, and principles of RF PCB design. It describes the development tools and application displaying measured values.

This thesis is based on a research project to monitor the temperature profile along a power cable using the fibre optic Distributed Temperature Sensing (DTS) technology. Based on the temperature measured by a DTS system, real time condition monitoring of power cables can be achieved. In this thesis, there are three main research themes. 1. Develop a DTS system for industrial applications. The entire hardware system and measuring software are developed to be an industrial product. Multiple functions are provided for the convenience of users to conduct temperature monitoring, temperature history logging and off-line simulation. 2. Enhance the robustness of the DTS system. An algorithm for signal compensation is developed to eliminate the signal fluctuation due to disturbance from the hardware and its working environment. It ensures robustness of the system in industrial environments and applicability to different system configurations. 3. Improve the accuracy of the DTS system. A calibration algorithm based on cubic spline fitting is developed to cope with non-uniform fibre loss in the system, which greatly improved the accuracy of the temperature decoding in real applications with unavoidable nonlinear characteristics. The developed DTS system and the algorithms have been verified by continuous experiments for about one year and achieved a temperature resolution of 0.1 degree Celsius, a spatial resolution of 1 meter, and a maximum error of 2 degree Celsius in an optic fibre with the length of 2910 metres.