[pt] O objetivo desta dissertação é analisar metrologicamente a aplicação de acelerômetros piezoelétricos à medição de vazão na indústria petrolífera. A motivação deste trabalho é analisar uma técnica de medição de vazão, recentemente desenvolvida, baseada na vibração captada por um acelerômetro ligado à superfície do duto. A metodologia do presente trabalho consistiu em realizar um estudo experimental para obtenção de dados em um laboratório acreditado de calibração de medidores de vazão, estimando-se uma vazão para cada vibração medida, acompanhada por uma análise de incertezas. Os resultados obtidos não estão conformes aos limites aceitáveis do ponto de vista da regulamentação para aplicação em medição de vazão na indústria petrolífera, no que se refere à medição fiscal e à medição para apropriação, segundo o Regulamento Técnico de Medição de Petróleo e Gás Natural (RTM). Contudo, a aplicação de acelerômetros ainda mostra-se oportuna à medição de vazão na indústria petrolífera, apesar da incerteza encontrada não adequar-se à regulamentação vigente para o setor, pois pode ser adotada para fins de medição operacional, na medição de água, sem interferir na instalação, de modo não invasivo e não intrusivo. / [en] The objective of this dissertation is to analyze metrologically the application of piezoelectric accelerometers in the measurement of flow rate in the oil industry. The motivation of this work is to analyze a technique of flow measurement, recently developed, based on the vibration captured by an accelerometer attached to the pipe surface. The methodology of this study consists of performing an experimental study to obtain data in an accredited laboratory for calibration of flowmeters, estimating a flow rate for each vibration measured accompanied by an uncertainty analysis. The results do not conform to acceptable limits from the viewpoint of the regulation for application in flow measurement in the oil industry, in that refers to the fiscal metering and to the measurement for appropriation, in accordance with the Technical Rules of Measurement of Petroleum and Natural Gas (RTM). However, the use of accelerometers still can be useful to measure flow rates in the oil industry, despite the uncertainty being not suitable for the current regulation of the sector, because it can be adopted in the operational measurement of water flow, without interfering in the installation, so being non-invasive and non-intrusive.

The thesis utilized physical testing and computer modeling to determine the feasibility of identifying a change to the mass or stiffness of a steel frame. Physical testing was performed using an accelerometer, linear shaker, and arbitrary function generator. Two methods of laboratory testing were developed: ambient vibration testing (AVT) and forced vibration testing (FVT). AVT was able to preliminarily identify the natural frequencies and mode shapes of the frame. FVT was able to precisely identify four distinct natural frequencies, mode shapes, and damping ratios. The baseline frame then underwent two physical changes: the addition of mass to its roof, and the addition of braces along one of its sides. FVT was used again to determine the natural frequencies, mode shapes, and damping ratios of the newly changed structure. An ETABS computer model was developed to represent the frame. This baseline model produced natural frequencies and mode shapes that closely matched the values determined by FVT. The mass and stiffness of this baseline model were then changed multiple times through the addition of mass and braces at various locations on the model. The frequencies and mode shapes were recorded for each change. Two methods were developed to identify the changes to the steel frame. The first method was able to determine which one of the models best represented a single change to the structure (adding mass to its roof). The second method was able to determine the combination of models that best represented the two concurrent changes to the structure (adding mass to its roof and braces to its sides). Both methods utilized the percent differences of each altered computer model relative to the original, and each method satisfactorily identified its respective physical alteration.

Objective: To investigate the extent to which changes in physical activity predict changes in abdominal fat in women over an 18-month period, while statistically controlling the effects of possible confounders, such as age, total body fat percent, and energy intake. Design: A prospective cohort design over 18 months. There was no intervention or treatment. Changes in objectively-measured physical activity were used to predict changes in abdominal fat over the study period. Subjects: 110 healthy, middle-aged women (mean: 41.3±3.3 yrs), primarily Caucasian, educated, and married. Measurements: An objective measure of physical activity (ACT) using CSA accelerometers, worn continuously for 7 consecutive days at baseline and again at follow-up. Total body fat and abdominal fat percent were assessed by dual energy x-ray absorptiometry (DEXA). Energy intake was estimated using 7-day, weighed food records for the days in which subjects wore accelerometers. Results: No significant change between baseline and follow-up means for abdominal fat, physical activity, or energy intake over the study period. Moreover, change in physical activity was not a significant predictor of change in abdominal fat, with or without statistical control of confounders. Change in energy intake was a predictor of abdominal fat (P=0.0688), and this association was strengthened after adjusting for age, baseline total body fat, and changes in physical activity. Conclusions: Apparently, when measured using accelerometers, changes in physical activity are not predictive of changes in abdominal fat over an 18-month period. However, changes in energy intake seem to predict changes in abdominal fat. Evidently, increases and decreases in abdominal fat are more a function of energy intake than physical activity in middle-aged women.

This study deals with tilt sensors. Besides others methods, accelerometers and gyroscopes are also convenient to solve this problem. Tilt sensors which are described in this thesis are working with capacitive, piezoresistive and thermal method. Capacitive accelerometers from producer Analog Devices, STmicro and Freescale, piezoresistive accelerometers from producer Panasonic Matsushita and gyroscope ADXRS300 are tested by practical measurement. Parameters of these accelerometers are found and they are compared with parameters from producer. Measurement reliability in this study is analysed as well. This thesis is divided in chapters theoretically describing principles of particular accelerometers and the chapters containing measured data evaluation.

Diploma thesis is focused on principles of measuring the vibrations using accelerometers and using them for making vibration measuring instrument with focus on modern integrated digital accelerometers. In the first part are described ways to measure acceleration and vibrations with available technical supplies with respecting place and purpose of measuring. In practical part are measured characteristics of used sensor, instrument for measuring vibrations is designed and built and for few experimental object vibrations or acceleration are measured and graphical interpreted.

The main goal of this work is to design an efficient and cheap car-alarm with an electricity consumption not exceeding 1mA in the stand-by mode. The first part focuses on the conception of the car-alarm. As the best option - GPS/GSM car-alarm conception is chosen. Then the design of the switching power supply, communication via RS232 with the GSM module, and GPS module, I2C communication with accelerometer and timer IC, and design of the display module are described. Furthermore, the process of how to code/decode sms into the PDU format is also discussed in this part. The second part provides some basic empirical characteristics of the switching power supply (efficiency, switching frequency etc.). Then the owchart of the main loop is explained, followed by an example of the sms which the car-alarm sends in case a car theft. Explanation of how to set up timer, acceleration threshold and the time between the check of the sms commads is the subject of the next section. Fifth part deals with the installation the car-alarm into a car which is illustrated on the Skoda Favorit example. Total costs and also different cost items are listed just before concluding and suggesting some potential improvements of the device.

This thesis deals with principles of measuring of acceleration with commercially available accelerometers and theoretical analyses of measuring of angular speed of rotational motion. Then the proposition of application’s connection controlled by microprocessor and software solution with implementation of serial communication interface is described. The function of the apparatus is examined with experimental measuring and elaborated protocol.

This diploma thesis deals with design and realization of control board with controlling program for stabilization platform application. Thesis is splitted in to six parts. In first part of thesis are summarized required parameters and properties of proposed system together with explanation of necessary theoretical basics. In second part of thesis is made analysis of sensors which are designated for sensing necessary magnitudes. Namely then magnetometer, accelerometer, gyroscope. For every sensor is there made analysis of influence caused by parasitic effects. In conclusion of second part is made choice of concrete sensors by choosing sensory module. Third part deals with conception of mechanical solution. Fourth part of thesis deals with design and construction of control board and also with description of circuit functional blocks. This is followed with fifth part which describing program equipment of board with setting up sensory module. In last part of thesis are described conclusions of testing.

The aim of this master’s thesis is to describe the basic measurement methods of micro-electromechanical inertial sensor, their physical principles and errors. Measurement of inertial sensors is very important for the parameterization of their errors and their subsequent mathematical model by which it is possible to minimize the measurement error impact on inertial navigation. The practical part is dedicated to create automated measurement setup for measurement stability of the offset. Hardware and software from National Instruments is used in measurement chain. The work is next focused on measuring seven inertial sensors based on three different physical principles. In addition to creating measurement setup, we also defined three inertial sensor parameters, describing theoretical behavior of the sensor output.

This master‘s thesis deals with applications for tablets running Android to control the car. As a control unit is used Raspberry Pi with Edimax WiFi module. The practical part focuses on the realization of applications for tablet and board layout for switching lights.