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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

Sběr a analýza dat z inteligentního včelího úlu

ŠIRHAL, Lukáš January 2018 (has links)
This thesis deals with creating hardware and software equipment of intelligent beehive for data collection purpose. Measurement characteristics are temperature, humidity, weight of beehive and audio record of bees. They are measured by available IoT technology. They are simple single-chip component with a clear focus. This thesis also include creation of software for measurements this characteristics and communications with server. The software featured of the remote server are also documented. This software analyze incoming measurement and also provides their displays. Software in this thesis is developed in language Python.
82

Silicon-germanium devices and circuits for high temperature applications

Thomas, Dylan Buxton 08 April 2010 (has links)
Using bandgap engineering, silicon-germanium (SiGe) BiCMOS technology effectively combines III-V transistor performance with the cost and integration advantages associated with CMOS manufacturing. The suitability of SiGe technology for cryogenic and radiation-intense environments is well known, yet SiGe has been generally overlooked for applications involving extreme high temperature operation. This work is an investigation into the potential capabilities of SiGe technology for operation up to 300°C, including the development of packaging and testing procedures to enable the necessary measurements. At the device level, SiGe heterojunction bipolar transistors (HBTs), field-effect transistors (FETs), and resistors are verified to maintain acceptable functionality across the temperature range, laying the foundation for high temperature circuit design. This work also includes the characterization of existing bandgap references circuits, redesign for high temperature operation, validation, and further optimization recommendations. In addition, the performance of temperature sensor, operational amplifier, and output buffer circuits under extreme high temperature conditions is presented. To the author's knowledge, this work represents the first demonstration of functional circuits from a SiGe technology platform in ambient temperatures up to 300°C; furthermore, the optimized bandgap reference presented in this work is believed to show the best performance recorded across a 500°C range in a bulk-silicon technology platform.
83

Design and development of novel radio frequency sensors based on far-field and near-field principles

Thai, Trang Thuy 13 January 2014 (has links)
The objective of this work is to enhance and advance sensing technologies with the design and development of novel radio frequency (RF) sensors based on far-field and near-field principles of the electromagnetic (EM) resonances. In the first part of this thesis, original design and development of a passive RF temperature sensor, a passive RF strain sensor, and a passive RF pressure sensor are presented. The RF temperature sensor is presented in Chapter 3. It is based on split ring resonators loaded with bimorph cantilevers. Its operating principles and equivalent circuits are discussed in Chapter 4, where the design concept is illustrated to be robust and highly adaptable to different sensing ranges, environments, and applicable to other type of sensing beyond temperatures. The passive RF strain sensor, based on a patch antenna loaded with a cantilever-integrated open loop, is presented in Chapter 5, where it is demonstrated to have the highest strain sensitivity in the same remote and passive class of sensors in the state-of-the-art. Chapter 6 describes the passive RF pressure sensor, which is based on a dual-band stacked-patch antenna that allows both identification and sensing to be embedded in its unique dual resonant responses. In the second part of this thesis, an original and first-of-its-kind RF transducer is presented that enables non-touch sensing of human fingers within 3 cm of proximity (based on one unit sensor cell). The RF transducer is based on a slotted microstrip patch coupled to a half-wavelength parallel-coupled microstrip filter operating in the frequency range of 6 – 8 GHz. The sensing mechanism is based on the EM near-field coupling between the resonator and the human finger. Fundamentally different from the electric field capacitive sensing, this new method of sensing, the first of its kind, based on near-field interference that produces a myriad of nonlinearities in the sensing response, can introduce new capabilities for the interface of electronic displays (the detection is based on pattern recognition). What set this sensor and its platform apart from previous proximity sensors and microwave sensing platforms is the low profile planar structure of the system, and its compatibility with mobile applications. The thesis provides both breadth and depth in the proposed design and development and thus presenting a complete research in its contributions to RF sensing.
84

Ring Oscillator Based Temperature Sensor

Walvekar, Trupti 07 1900 (has links) (PDF)
The temperature sensor design discussed in this thesis, is meant mainly to monitor temperature at power outlets. Current variations in power cords have a direct impact on the surrounding temperature. Sensing these variations ,enables us to take necessary measures to prevent any hazards due to temperature rise. Thus, for this application we require a sensor with a moderate temperature error (_10C) over a sensing range of -200C to 1500C. Low power consumption and simple digitizing scheme alleviate measurement errors due to self heating effects of the sensor. A current starved inverter based ring oscillator was chosen for the sensor design in 130nm technology. The inverter delay variation with temperature is used for sensing. Linearity and process invariancy of these characteristics are fundamental to the sensor design. We observed through simulations, and confirmed by mathematical analysis, that the sensing characteristics are governed by bias current dependence on temperature. Control voltage for the bias circuitry of the oscillator determines current through the inverter stages. Hence, for linear sensing characteristics, a control voltage(Vc) just above the maximum threshold voltage of bias transistor is used. This enables generation of PTAT saturation current for current starved inverters, due to dominance of threshold voltage decrease with temperature over mobility decrease. I.Another limitation, process dependency of the sensing characteristics, was overcome through the proposed calibration based compensation technique. A changing Vc proportional to threshold voltage variation with process, process independent bias current and current temperature characteristics were obtained. This compensated for the process variation effects on frequency. Thus, a variable Vc was generated using a reference with low temperature sensitivity of 17.6_V=0C, and resistive divider combinations for various processes. Incorporating this compensation technique we achieved good linearity in sensor characteristics and a maximum temperature error of± 1.60C over the sensing range. The sensor consumes a low power of 0.29mW and also occupies minimal area.
85

Návrh systému řízení a diagnostiky ohřevu vody s využitím solární energie / Design of system control and diagnostics water heating using solar energy

Kužel, Kristián January 2013 (has links)
This thesis deals with problems related to heating of hot service water. It focuses on solar water heating, describes individual types of solar panels and summarizes the existing information about solar water heating. It demonstrates actual problems of solar system solution on a specific example of a two-generation family house, where it analyses possibilities of diagnostics and control of such system. It also deals with suggestions of possible expansion of the current solar system.
86

Měření veličin ve stavebních konstrukcích / Meassuring system for building constructions

Flagar, Vojtěch January 2017 (has links)
This paper deals with the hardware and software design of the data acquisition distributed system with large amount of connected sensors. The intended application of this work is measuring some physical quantities in the building constructions. The designed system is hierarchically divided into the three levels. On the highest level there is a single-board computer Raspberry Pi which is used as a master on RS-485 bus. There can be up to 32 slave devices on the bus while each of them collects data from the sensors connected to 4-channel I2C bus. At the same time the Raspberry Pi is used as a web server, providing the user interface of the system.
87

APPLICATIONS OF MICROHEATER/RESISTANCE TEMPERATURE DETECTOR AND ELECTRICAL/OPTICAL CHARACTERIZATION OF METALLIC NANOWIRES WITH GRAPHENE HYBRID NETWORKS

Doosan Back (6872132) 16 December 2020 (has links)
<div>A microheater and resistance temperature detector (RTD) are designed and fabricated for various applications. First, a hierarchical manifold microchannel heatsink with an integrated microheater and RTDs is demonstrated. Microfluidic cooling within the embedded heat sink improves heat dissipation, with two-phase operation offering the potential for dissipation of very high heat fluxes while maintaining moderate chip temperatures. To enable multi-chip stacking and other heterogeneous packaging approaches, it is important to densely integrate all fluid flow paths into the device. Therefore, the details of heatsink layouts and fabrication processes are introduced. Characterization of two-phase cooling as well as reliability of the microheater/RTDs are discussed. In addition, another application of microheater for mining particle detection using interdigitated capacitive sensor. While current personal monitoring devices are optimized for monitoring microscale particles, a higher resolution technique is required to detect sub-micron and nanoscale particulate matters (PM) due to smaller volume and mass of the particles. The detection capability of the capacitive sensor for sub-micron and nanoparticles are presented, and an incorporated microheater improved stable capacitive sensor reading under air flow and various humidity. </div><div>This paper also introduces the characterization of nanomaterials such as metallic nanowires (NWs) and single layer graphene. First, the copper nanowire (CuNW)/graphene hybrid networks for transparent conductors (TC) is investigated. Though indium tin oxide (ITO) has been widely used, demands for the next generation of TC is increasing due to a limited supply of indium. Thus, the optical and electrical properties of CuNW/graphene hybrid network are compared with other transparent conductive materials including ITO. Secondly, silver nanowire (AgNW) growth technique using electrodeposition is introduced. A vertically aligned branched AgNW arrays is made using a porous anodic alumina template and the optical properties of the structure are discussed.</div><div><br></div>
88

Measurement of Core Body Temperature with a Powered Toothbrush

Pilla, Satya Sai Naga Jaya Koushik, Konduru, Vamsi Reddy January 2022 (has links)
We need to employ modern-day technologies in our daily lives to make our life easier. In this thesis, we analyze the user’s oral hygiene habits and core body temperature to help people to track the state of their health. We designed a system in which the data are directly extracted from the mouth, then stored and presented in the application. By means of the system, the people can keep track oftheir core temperature without any extra function apart from their daily chores.The system can also help to keep track of the health of people with symptoms ofdementia and Alzheimer. We used an LM35 temperature sensor to measure temperature. The sensor is mounted on a powered toothbrush head. When the user starts to brush, the sensor records the temperature data for seven times in two minutes of an average brush time and sends it to the mobile application using WiFi. We used a NodeMCUboard, ThingSpeak server and MIT inventor app to transfer the data and designthe mobile application.
89

Humidity Sensing Behavior of Endohedral Li-Doped and Undoped SWCNT/SDBS Composite Films

Müller, Christian, Al-Hamry, Ammar, Kanoun, Olfa, Rahaman, Mahfujur, Zahn, Dietrich R. T., Matsubara, Elaine Yoshiko, Rosolen, José Mauricio 14 February 2019 (has links)
We have investigated single-walled carbon nanotube (SWCNT) networks wrapped with the cationic surfactant sodium dodecyl-benzenesulfonate (SBDS) as promising candidates for water detection. This is the first time that the humidity behavior of endohedral Li-doped (Li@) and undoped SWCNTs/SDBS has been shown. We identified a strong and almost monotonic decrease in resistance as humidity increased from 11 to 97%. Sensitivities varied between −3 and 65% in the entire humidity range. Electrical characterization, Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM) analysis revealed that a combination of the electron donor behavior of the water molecules with Poole-Frenkel conduction accounted for the resistive humidity response in the Li@SWCNT/SDBS and undoped SWCNT/SDBS networks. We found that Li@SWCNTs boosted the semiconducting character in mixtures of metallic/semiconducting SWCNT beams. Moreover, electrical characterization of the sensor suggested that endohedral Li doping produced SWCNT beams with high concentration of semiconducting tubes. We also investigated how frequency influenced film humidity sensing behavior and how this behavior of SWCNT/SDBS films depended on temperature from 20 to 80 ∘ C. The present results will certainly aid design and optimization of SWCNT films with different dopants for humidity or gas sensing in general.
90

TEMPENSURE, A BLOCKCHAIN SYSTEM FOR TEMPERATURE CONTROL IN COLD CHAIN LOGISTICS

Matthew L Schnell (13206366) 05 August 2022 (has links)
<p>  </p> <p>Cold chain logistics comprise a large portion of transported pharmaceutical medications and raw materials which must be preserved at specified temperatures to maintain consumer safety and efficacy. An immutable record of temperatures of transported pharmaceutical goods allows for mitigation of temperature-related issues of such drugs and their raw components. The recording of this information on a blockchain creates such an immutable record of this information which can be readily accessed by any relevant party. This can allow for any components which have not been kept at the appropriate temperatures to be removed from production. These data can also be used as inputs for smart contracts or for data analytic purposes. </p> <p>A theoretical framework for such a system, referred to as “TempEnsure” is described, which provides digital capture of the internal temperature of temperature-controlled shipping containers. The data are recorded in a blockchain system. Real world testing of this system was not possible due to monetary constraints, but the functional elements of the system, as well as potential improvements for the system, are discussed.</p>

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