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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.
1

Kraftanalys och framtagning av mätanordning för vertikala vindkraftverket Lucias bärarmar

Hammar, Henning, Constanda, Daniel January 2011 (has links)
The project contains a force analysis of the vertical axis wind turbine Lucia's supporting arms and a measuring device to experimentally measure the forces is made. The forces between the supporting arms and the tower are calculated theoretically and then simulated by a computere. A measuring devise is then designed to measure the forces experimentally. The forces acting on the attachment between the supporting arms and the tower is primarily the centripetal force, gravitational force and the aerodynamic forces on the rotor wings. The maximum forces were theoretically calculated and is 13.38 kN along the x-axis, -0.25 kN along the y-axis and then 0.5 kN along the z-axis. The axis are acording to a rotational reference system where the x-axis runs along the supporting arm and the y-axis runs along the axis of rotation. The maximum torque that occurs is 0.53 kNm along the y-axis and 1.29 kNm along the z-axis. The size of the forces have been confirmed with a deviation of up to 1.8 % in the simulation using SolidWorks 2010. For the experimental measurements a measuring device has been developed which consists of S-load cells with wave indicator and transmitter, an attachment for the measuring equipment and distanceplates to stabilize the rotor. S-load cells, wave indicator and transmitter were ordered and drawings for the attachment of the measuring equipment and spacer plates was done. The eigenfrequencies and the stress have been investigated for the parts. The eigenfrequencies for the wind turbine was estimated to decline up to 13 % when the measuring device was mounted and the lowest Factor of Safety was 1.67. Before the attachment of the measuring device and the spacer plates can be ordered the attachment of the supporting arms, how the loadcells should be attached to the device and the safety margins need to be examined.
2

Temperament in beef cattle : methods of measurement, consistency and relationship to production

Sebastian, Thomas 14 December 2007
Two behavioural studies were conducted at the University of Saskatchewan beef feedlot. In the first study, the temperament of 400 steers was determined using both objective and subjective measures. The consistency of temperament, over repeated tests and between different measures, was also tested. The objective behavioural tests were conducted during the individual restraint of the steers using strain gauges and an MMD (movement-measuring-device). The time required for the steers to exit the area was also recorded. Subjective assessment of animals responsiveness during restraint was recorded on a scale of 1-5 (calm to wild). The consistency of individual differences in a steers response within the evaluation series and across repetitions, shows that this trait may represent a stable personality of the animal. The significant relationship between objective and subjective measures demonstrates that objective measures of temperament can be used to replace the traditional subjective scale as it has the added advantage of reducing inter- and intra-observer variability. The positive relationship of subjective scores and MMD values with the steers performance (average daily weight gain) shows not only that a calm temperament is conducive to productivity, but also that objective measures can replace subjective techniques for assessing temperament for performance evaluation. In the second study the reactivity of a subset of the original 400 steers (262 animals from 8 pens) to a novel stimulus was assessed. The purpose of this experiment was to determine if a steers behavioural response in the novel test was correlated to its temperament assessment determined in the first study. A remote controlled ball was dropped from the ceiling of a salt feeder while a steer licked the salt. Two overhead cameras connected to a monitor through a VCR and time lapse recorder permitted us to observe and document the response. A lack of correlation between measures of handling and novelty measures show that reactivity of animals in the handling chute and their responsiveness to the novel stimulus do not represent one and the same trait.
3

Temperament in beef cattle : methods of measurement, consistency and relationship to production

Sebastian, Thomas 14 December 2007 (has links)
Two behavioural studies were conducted at the University of Saskatchewan beef feedlot. In the first study, the temperament of 400 steers was determined using both objective and subjective measures. The consistency of temperament, over repeated tests and between different measures, was also tested. The objective behavioural tests were conducted during the individual restraint of the steers using strain gauges and an MMD (movement-measuring-device). The time required for the steers to exit the area was also recorded. Subjective assessment of animals responsiveness during restraint was recorded on a scale of 1-5 (calm to wild). The consistency of individual differences in a steers response within the evaluation series and across repetitions, shows that this trait may represent a stable personality of the animal. The significant relationship between objective and subjective measures demonstrates that objective measures of temperament can be used to replace the traditional subjective scale as it has the added advantage of reducing inter- and intra-observer variability. The positive relationship of subjective scores and MMD values with the steers performance (average daily weight gain) shows not only that a calm temperament is conducive to productivity, but also that objective measures can replace subjective techniques for assessing temperament for performance evaluation. In the second study the reactivity of a subset of the original 400 steers (262 animals from 8 pens) to a novel stimulus was assessed. The purpose of this experiment was to determine if a steers behavioural response in the novel test was correlated to its temperament assessment determined in the first study. A remote controlled ball was dropped from the ceiling of a salt feeder while a steer licked the salt. Two overhead cameras connected to a monitor through a VCR and time lapse recorder permitted us to observe and document the response. A lack of correlation between measures of handling and novelty measures show that reactivity of animals in the handling chute and their responsiveness to the novel stimulus do not represent one and the same trait.
4

Meřicí přípravek připojitelný přes rozhraní USB / Measuring device connected over USB

Flek, Tomáš January 2011 (has links)
In essence, this master’s thesis focuses on search and project on optimal electrical scheme, which will substitute for digital oscilloscope function. The thesis consist of three parts, first part is about problems associated with oscilloscope signal sampling and data bus descriptions, second part where are selected particular circuits, electrical scheme, eventually shown different options which could be used. Third part consists of software function description developed for controlling microprocessor. In choosing of analog devices, are focused on parameters like maximal input voltage on which the device has most ideal parameters, but also parameters, which are critical for particular block, like for example input impedance, device noise, operating amplifier input voltage and current offset. All devices were chosen with battery supply possibility, so what the lowest possible power consumption. In this thesis is theoretically described each circuit block and reasons for their selection.
5

Realization of a Measuring Device for Recordning the Relative Movement between Residual Limb and Prosthetic Socket

Whitmore, Sigrid Ilona 02 August 2018 (has links)
Relative motion between residual limb and prosthetic socket is an indication of poor fit. Both the fabrication and fitting processes are highly subjective and a favorable result depends upon the technician's expertise. Although numerous methods exist to measure the relative motion, all have limitations and are not well suited for clinical use. A measurement system using optical sensors has been proposed by students at the Technische Universität Darmstadt and evaluations of a functional model have yielded promising results. In this thesis, the existing functional model is improved and expanded to use an array of sensors. A new microcontroller is selected and incorporated into the system. The software and data communication are optimized for fast, reliable performance and the system is then evaluated on a test rig to determine favorable calibration settings and quantify performance. System frequencies up to 1299 Hz are achieved. It is found that the surface microstructure has a dominant effect over short measurement distances; calibrations performed over longer distances are to be preferred. For the chosen calibration factors, the greatest relative errors over a 40 mm distance are found to be 0.90% ± 0.51% in the X direction and -4.76% ± 1.61% in the Y-direction. A systematic drift is also identified. The final system accommodates up to eight sensors and is controlled from a feature-rich MATLAB GUI. / Master of Science / In lower limb prosthetics, the amount of relative motion between the prosthesis and residual limb is considered an indicator of the quality of fit. As existing methods for measuring this motion are generally difficult to use, a simpler system is desired. The task for this master's thesis is to develop an existing functional model into a measurement system with multiple sensors and validate its performance. The first step is to upgrade the microcontroller responsible for reading the sensor data and transmitting it to the PC. The original codes for both the microcontroller and PC-side Graphical User Interface (GUI) are then examined and optimized for maximum speed. The system is expanded to accommodate multiple sensors and its performance evaluated using a test-rig. Finally, the completed system is prepared for use in a future study by creating the appropriate component housings, wiring, and software functionalities.
6

Fyzikální měření pomocí mobilního telefonu / Physical measure by the mobile phone

MATYS, Jaroslav January 2016 (has links)
This diploma thesis topic "Physical measure by the mobile phone" deals in theoretical part with term BYOD (Bring Your Own Device) and lesson 1:1, where is solving motivation of integrating devices into the lessons, what are the advantages and disadvatages of this problems and also what are the worries that pedagogues could have. Then thesis deals with equipment of mobile phones, principle of sensors functioning and in the end deals with searches of application for physical measuring by the mobile phones sensors, actual to the date of the writing this thesis. In the practical part thesis deals with comparison of values from aplication to the laboratory equipment. In the end deals with proposals of lessons activities with mobile applications.
7

Cost-efficient approaches to measure carbon dioxide (CO2) under different environmental factors such as temperature and humidity using mini loggers / Kostnadseffektiva sätt att mäta koldioxid (CO2) under olika temperatur och luftfuktighet med mini-sensorer

Lander, Jasmine January 2020 (has links)
Fluxes of carbon dioxide (CO2), being a major greenhouse gas, are of great importance to understand and monitor. Findings have shown that while CO2 emissions enhanced by humans triggered the greenhouse gas effect, several significant CO2 fluxes in nature that are climate sensitive may still be poorly constrained, especially those from inland waters and its surrounding soils and sediments. This including different processes such as decomposers degrading organic material. At present, direct measurements of CO2 from soils, waters or CO2 concentrations in surface water, are typically labour intensive or require costly equipment. Therefore, small inexpensive CO2 mini loggers, originally made for indoor air quality monitoring, are for this project being developed further for field use, as a convenient equipment to measure CO2 emissions. However, a requirement is that the mini loggers are stable and robust against interference by other air components, including water vapour, and physical factors such as temperature. Therefore, the mini loggers were for this project studied further under different environmental conditions such as temperature and humidity in a controlled environment. The results were analysed using multiple regression analysis where the CO2 concentration (CO2), measured by the LGR instrument, versus the logger IR signal (IR), temperature (T) and relative humidity (RH) were studied. Unlike some previous studies, this project studied a large CO2 concentration interval (400 – 10 000 ppm).  The results show that there was a strong regression for IR versus CO2. The regression for both RH and the T was on the other hand very weak. However, there were factors that could have affected the mini logger. This since it was noticed that the mini loggers’ ability to calculate the CO2 concentration was worsened when the humidity was increased during the experiments. It is believed that the cause was condensed water, gathering in the inner parts of the mini logger. This because the sensor chamber had a lower temperature than the hot air entering the sensor chamber from the humidity bottle, together with the CO2, leading to condensation. Hence, prevention of condensation inside the measurement cell is important. However, the results from the analysis shows that the factors; RH and T do not need to be taken into account when studying the CO2 concentration over a larger interval, as long as the conditions are not condensing.
8

Měření radiální tuhosti pneumatik / Tyre Radial Stiffness Measurement

Novodomský, Tomáš January 2020 (has links)
This thesis deals with the radial stiffness of a tyre. The first part of is devoted to a brief description of a tyre construction. The next part is devoted to measuring the radial stiffness of a tyre and the design of a new measuring device. The last part of the thesis deals with the influence of the radial stiffness of a tyre on the vertical dynamics of ta vehicle and simulations of this effect in the MATLAB / Simulink software.
9

Analýza rizik a bezpečnosti u optické kontrolní stanice / Risk and safety analysis by optical test unit

Mank, Slavomír January 2014 (has links)
This thesis discusses of safety of machinery from production of our company. It is an optical measuring station to check spin valve stroke of inlet valve of the high pressure fuel pump. It also deals with the analysis of the legislative situation in this field. After initially acquaintance, the block diagram creating and definition of the limits, was conducted risk analysis of machinery.
10

Automatizované měření charakteristik dvojbranů v DC, AC a časové oblasti / Measurement setup for DC, AC and transient testing of two-ports

Káňa, Vojtěch January 2017 (has links)
This master´s thesis describes about automated measurements of two – ports of frequency, time and DC area. Gradually, there is elaborated several theoretical foundations dealing with this issue. For example, different types of buses, available programs and general theory of two – ports circuits. Also a method for solving and implementing a measuring device for communication between apparatuses and DUT is designed and described. In conclusion, the results and evaluation of measurement are processed.

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