The HAbitability, Brine Irradiation and Temperature Package (HABIT) instrument of the ExoMars Surface Platform will investigate the present day habitability of Mars at the near surface environment. This instrument includes three Atmospheric Temperature Sensor's (ATS's) which are similar to the ones previously used on the Rover Environmental Monitoring Station (REMS) of the Mars Science Laboratory (MSL) rover, that has now been operating on Mars for more than four years. The ATS of REMS is only used to provide the air temperature, however on HABIT it will be used furthermore to provide information about winds and heat transfer at the surface of Mars. The retrieval method needs to be further investigated and validated. This master thesis is aimed at three goals: 1) the development and testing of an Earth Scaled Atmospheric Temperature Sensor (ESATS) to test the retrieval concept; 2) the validation with other Earth-based standard wind sensing technologies under outdoors uncontrolled conditions; and 3) the analysis of the existing observations of the ATS of REMS on Mars to get a better understanding of its expected future performance on HABIT once it operates on Mars. The ESATS is an up-scaled semi-autonomous prototype version of an ATS which consists of a rod of different size and material to those that are used on REMS and will be used on HABIT. The rod shall be heated from the base where it is attached to. The temperature profile shall be measured at three different measurement points. All these temperatures are different from the one of the atmosphere to which the rod is exposed to. The temperature profile along the rod changes depending on the air temperature, air density and the wind speed because of the convective heat transfer. A preliminar analysis is used to define what is the ideal length of the rod, and what is the material that is best adapted for this experimental prototype. Since the air density is needed to retrieve the wind speed, the pressure will be monitored as well. In parallel, a second wind measuring technique based on the dynamic pressure changes detected in a Pitot tube is used as control. The measuring campaign is subdivided in several stages: 1) The first part will take place in a laboratory, where the system is exposed to static conditions with no heating and no wind, which means that there is no forced convection caused by wind. In this setup all sensors are calibrated against one another and with help of a reference resistor the temperature sensors are also calibrated to 273.15K. Additionally different Operational Amplifiers (OpAmps) will be used to observe how the noise level is affecting the measurements, so that the best one will be used in the end. 2) Furthermore, the best position to place the intermediate temperature sensor is investigated by testing one of the rods with different locations of the middle temperature sensor. 3) Next, also within the laboratory environment, the different rods are used to obtain the temperature profile and retrieve the air temperature and heat transfer values, solving the equations that describe the heat transfer problem under static conditions. 4) The second part of the measurement campaign will take place outdoors, where the ESATS is exposed to forced convection due to wind. In this setting first the influence of the Sun on the system is measured, as it is important to know, if the measurement can be performed when the illumination conditions change. 5) Next, the system is tested with the 50cm rod in long term tests with the reference measurement of a commercial weather station (HOBO) next to it. With the data obtained the convective heat transfer method is used and the retrieved wind speed is compared to the one received from the HOBO. Finally, to get a better understanding of its expected future performance on HABIT once it operates on Mars, the data of the ATS of REMS is used to perform the wind speed retrieval for Mars and to compare it with the data received from the REMS wind sensor. It is only operating during daytime and has still difficulties to retrieve a precise wind speed. The measurement campaign has given several information about ATS in general. First it was decided to place the temperature sensor in the middle at 1/4 of the rod length, which is optimal for the retrieval process and which is also coincident with the one chosen for HABIT and REMS. The measurements in the laboratory are providing good and constant temperature profiles with the chosen setup which correspond with the one expected from the equations that describe the heat transfer problem in a long rod. On the other hand, it is not possible to calculate a valid ambient temperature for the short rods, which is because of an overheated boundary layer around the rods due to the heating. For this reason, it is recommended to use the longest rod in the lab. For outside testing the influence of the Sun could be confirmed and was affecting the measurements of the copper rod. During the time span where the prototype was in the Sun, it was not possible to get any reasonable results. The next measurement campaign was defined in a shadowed area with diffuse light only. Finally, the tests of exposure to dynamic changes over time are in excellent agreement with the ones provided by the HOBO station and can even give a better resolution and sensitivity to small changes of wind magnitude. This prototype has confirmed experimentally, that under Earth conditions, this method can be used to retrieve the wind speed. Finally, the Martian data of the REMS ATS are analyzed and the comparisons suggest that the method is sensitive to wind changes on Mars as well, and shows better time and magnitude resolution than the existing REMS wind sensor. This confirms that this method can be successfully used for the HABIT sensor. In this work the methodology that shall be used on HABIT to retrieve the convective heat transfer and wind on the surface of Mars is validated for Earth outdoors conditions. It is recommended to verify the obtained results with tests in a wind tunnel and to see how the system will behave with a higher heating and different rod materials. Furthermore, the setup should be tested in a way which makes it possible to determine the different directions of the wind.

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The thesis deals with the design and implementation of broadband and narrowband antennas and their applications in practical environment. In this thesis, a new concept for designing the UWB antenna is proposed based on the CRLH metamaterials and this UWB antenna covers a frequency range from 2.45 GHz to 11.6 GHz. Based on the design of the UWB antenna, another antenna is developed that can cover a very wide bandwidth i.e from 0.66 GHz to 120 GHz. This antenna can not only be used for UWB applications but also for other communication systems working below the UWB spectrum such as GSM, GPS, PCS and Bluetooth. The proposed antenna covering the bandwidth from 0.66 GHz to 120 GHz is by far the largest bandwidth antenna developed based on metamaterials. Wide band antennas are not preferred for sensing purpose as it is difficult to differentiate the received signals. A multiband antenna which can be used as a strain sensor for structural health monitoring is proposed. The idea is to correlate the strain applied along the length or width with the multiple resonant frequencies. This gives the advantage of detecting the strain applied along any direction (either length or width), thus increasing the sensing accuracy. Design and application of a narrow-band antenna as a temperature sensor is also presented. This sensor can be used to detect very high temperature changes (>10000C). This sensor does not require a battery, can be probed wirelessly, simple and can be easily fabricated, can withstand harsh environmental conditions.

Materiais cerâmicos à base de óxidos de manganês, de níquel e de cobalto foram preparados por meio de mistura de óxidos seguida de homogeneização e sinterização controlada em 1250 °C. Os óxidos foram caracterizados por meio das técnicas de difração de raios X, fluorescência de raios X, termogravimetria e determinação de distribuição de tamanho de partículas por espalhamento laser. A caracterização dos corpos sinterizados foi feita por meio de análise por microscopia eletrônica de varredura, difração de raios X e fluorescência de raios X. O comportamento termistor foi estudado por meio de medidas de resistividade elétrica pela técnica dc de duas pontas de prova entre temperatura ambiente e 220 °C. Os principais resultados mostram ser possível a preparação de termistores em ampla faixa de resposta elétrica por meio da variação da composição relativa dos óxidos de manganês, de níquel e de cobalto. / Ceramic tliermistors based on manganese, nickel and cobalt oxides were prepared by mixing these oxides followed by pressing and sintering at 1250 °C range. The oxides were characterized by X-ray diffraction, X-ray fluorescence, thermogravimetry and differential thermal analysis, and by the determination of particle size distribution by laser scattering. After sintering. X-ray diffraction. X-ray fluorescence and scanning electron microscopy analyses were carried out. The thermistor behavior was studied by two-probe dc electrical resistivity measurements in the room temperature-220 °C range. The main results show the possibility of designing thermistors with the required electrical response by suitable choice of the relative concentrations of the precursor oxides.

Materiais cerâmicos à base de óxidos de manganês, de níquel e de cobalto foram preparados por meio de mistura de óxidos seguida de homogeneização e sinterização controlada em 1250 °C. Os óxidos foram caracterizados por meio das técnicas de difração de raios X, fluorescência de raios X, termogravimetria e determinação de distribuição de tamanho de partículas por espalhamento laser. A caracterização dos corpos sinterizados foi feita por meio de análise por microscopia eletrônica de varredura, difração de raios X e fluorescência de raios X. O comportamento termistor foi estudado por meio de medidas de resistividade elétrica pela técnica dc de duas pontas de prova entre temperatura ambiente e 220 °C. Os principais resultados mostram ser possível a preparação de termistores em ampla faixa de resposta elétrica por meio da variação da composição relativa dos óxidos de manganês, de níquel e de cobalto. / Ceramic tliermistors based on manganese, nickel and cobalt oxides were prepared by mixing these oxides followed by pressing and sintering at 1250 °C range. The oxides were characterized by X-ray diffraction, X-ray fluorescence, thermogravimetry and differential thermal analysis, and by the determination of particle size distribution by laser scattering. After sintering. X-ray diffraction. X-ray fluorescence and scanning electron microscopy analyses were carried out. The thermistor behavior was studied by two-probe dc electrical resistivity measurements in the room temperature-220 °C range. The main results show the possibility of designing thermistors with the required electrical response by suitable choice of the relative concentrations of the precursor oxides.

The objective of this investigation was to develop micro/nano-scale temperature sensors for measuring surface temperature transients in multi-phase flows and heat transfer. Surface temperature fluctuations were measured on substrates exposed to phase change processes. Prior reports in the literature indicate that these miniature scale surface temperature fluctuations can result in 60-90 percent of the total heat flux during phase change heat transfer. In this study, DTS (Diode Temperature Sensors) were fabricated with a doping depth of ~100 nm on n-type silicon to measure the surface temperature transients on a substrate exposed to droplet impingement cooling. DTS are expected to have better sensor characteristics compared to TFTs (Thin Film Thermocouples), due to their small size and faster response (which comes at the expense of the smaller operating temperature range). Additional advantages of DTS include the availability of robust commercial micro fabrication processes (with diode and transistor node sizes currently in the size range of ~ 30 nm), and that only 2N wire leads can be used to interrogate a set of N x N array of sensors (in contrast thermocouples require 2 N x N wire leads for N x N sensor array). The DTS array was fabricated using conventional semi-conductor processes. The temperature response of the TFT and DTS was also calibrated using NIST standards. Transient temperature response of the DTS was recorded using droplet impingement cooling experiments. The droplet impingement cooling experiments were performed for two different test fluids (acetone and ethanol). An infrared camera was used to verify the surface temperature of the substrate and compare these measurements with the temperature values recorded by individual DTS. PVD (Physical Vapor Deposition) was used for obtaining the catalyst coatings for subsequent CNT synthesis using CVD (Chemical Vapor Deposition) as well as for fabricating the thin film thermocouple (TFT) arrays using the "lift-off" process. Flow boiling experiments were conducted for three different substrates. Flow boiling experiments on bare silicon wafer surface were treated as the control experiment, and the results were compared with that of CNT (Carbon Nano-Tube) coated silicon wafer surfaces. Similar experiments were also performed on a pure copper surface. In addition, experiments were performed using compact condensers. Micro-scale patterns fabricated on the refrigerant side of the compact heat exchanger were observed to cause significant enhancement of the condensation heat transfer coefficient.

The objectives of the proposed research are to model, optimize, and control variable frequency microwave (VFM) curing of polymer dielectrics. With an increasing demand for new materials and improved material properties, there is a corresponding demand for new material processing techniques that lead to comparable or better material properties than conventional methods. Presently, conventional thermal processing steps can take several hours. A new thermal processing technique known as variable frequency microwave curing can perform the same processing steps in minutes without compromising the intrinsic material properties. Current limitations in VFM processing include uncertain process characterization methods, lack of reliable temperature measuring techniques, and the lack of control over the various processes occurring in the VFM chamber. Therefore, the proposed research addressed these challenges by: (1) development of accurate empirical process models using statistical experimental design and neural networks; (2) recipe synthesis using genetic algorithms; (3) implementation of an acoustic temperature sensor for VFM process monitoring; and (4) implementation of neural control strategies for VFM processing. and #8194;

Many applications in microelectromechanical systems such as smart living space sensing system, microchannel system on chip and biomedical sensing system usually require instantaneously compensating or controlling the temperature of chip to acquire more linear and accurate output signal. So it is necessary to develop a micro temperature sensor or micro-hot-plate which has highly thermal isolation and low power characteristics. This thesis aims to design and fabricate a low power micro-hot-plate and a high-sensitivity temperature sensor for portable applications. This dissertation utilized a high power E-beam evaporator to deposit the platinum thin film as the material of temperature sensing and heating. The Pt layer is patterned using the lift-off technique. In addition, the micro-hot-plate can be released from the silicon substrate as a floating thin-plate using TMAH-based anisotropic etching technology. The floating structure can improve the thermal isolation and reduce the power loss through the silicon substrate. In this study, the higher temperature sensitivity (1914 ppm/¢J) and optimized sensing linearity ( > 99.9 %) of the platinum-based temperature sensor is demonstrated. On the other hand, the heating power of the floating micro-hot-plate developed in this research is only 14 mW when it be heated to 300 ¢J and the power efficiency is very high (18.3 ¢J/mW).

In this thesis, the details of the design, fabrication, and characterization of an optical, integrated hydrogen gas and temperature sensor are explored. The hydrogen sensor is implemented by coating a ridge waveguide with a thin layer of palladium and shows very good response time and detection response for hydrogen concentrations ranging from 0.5-4%, both of which compare very favourably to similar existing technologies. Multiple film thicknesses were tested and it was found that thinner films give a faster response time at the expense of a reduced detection response. The temperature sensor is implemented with a multi-mode interferometer coupled ring resonator and has a sensing range of 100 K with good sensitivity. Both sensors are fabricated on a silicon-on-insulator platform and could easily be integrated together onto a single chip as part of an optical nose technology that would have the ability to sense multiple environmental factors simultaneously.