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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.
11

Microfluidic system with open loop control for rapid infrared reverse transcription quantitative PCR (RT-qPCR)

Saunders, Daniel Curtis 05 July 2012 (has links)
Microfluidic techniques have allowed for fast, sensitive, and low cost applications of the Polymerase Chain Reaction (PCR) through the use of small reaction volumes, rapid amplification speeds, and the on-chip integration of upstream and downstream sample handling processes including purification and electrophoretic separation functionality. While such systems are capable of measuring the expression levels of thousands of genes simultaneously, or in hundreds of cells, or with sample-in and answer-out capability, none of these systems are easily scalable in the time domain. Because of this, the field of gene expression measurement has yet to fully utilize the advantages of microfluidic PCR in developing systems to measure changes in gene expression in increments of hours rather than days. In this project, we developed a microfluidic RT-qPCR system that utilizes infrared heating and open-loop control to reliably reverse transcribe, amplify, and detect samples in a single 1 μl polymer chip. Optimized power profiles were created that allow for fast heating and cooling rates while minimizing undershoot and overshoot from the desired hold temperatures. By utilizing repeatable microfluidic chip manufacturing techniques, and by controlling the environment around the chip, the same open loop program can repeatedly amplify multiple samples without any need for temperature feedback or recalibration between runs. Furthermore, the system was designed to operate on top of a fluorescence microscope to enable real-time fluorescence detection and quantification of starting copy number. By eliminating complicated setup procedures and calibration runs, this system increases the practicality of measuring gene expression at a high temporal frequency.
12

Laser Machining and Near Field Microwave Microscopy of Silver Inks for 3D Printable RF Devices

Ross, Anthony J., III 29 June 2017 (has links)
3D printable materials for RF devices need improvement in order to satisfy the demand for higher frequency and lower loss performance. Characterization of materials that have shown improvements of conductor conductivity have been performed. By using a laser machining technique the loss of a 3D printed 2.45 GHz microstrip Square Open Loop Resonator (SOLR) bandpass filter has been shown to improve by 2.1dB, along with an increase in bandwidth from 10% to 12.7% when compared to a SOLR filter that has not been laser machined. Both laser machined and microwaved silver inks have been mapped for conductivity using a Near Field Microwave Microscope (NFMM) and have shown improvement of conductivity compared to inks that have been cured using standard methods.
13

Braking with a Directional Control Valve in a Hydraulic Open-Loop Transmission

Karlborg, Jonathan, Sten, Emil January 2021 (has links)
This project presents an investigation if natural braking characteristics could be achieved on an open-loop hydraulic transmission without a brake valve. The goal with the simplified system was to utilize the directional control valve to achieve similar functionality as the brake valve does in the conventional system. If the solution functions properly, it will reduce costs, save time and simplify the conventional system which uses a dedicated brake valve. With a simulation model and practical experiments, the simplified system was thoroughly studied and tested. Two different concepts of how to control the directional control valve were developed, named Fixed Control and Torque Control. The Fixed Control concept has a predetermined de-stroking profile which is not affected by other system signals other than the gas pedal signal. The Torque Control concept uses in addition to the gas pedal signal, pressure sensors over the motors to maintain a constant braking torque. Both developed concepts were able to produce natural braking characteristics. However, the Torque Control concept performed better at different circumstances. Respective concept can be tuned further for improvements, but in the scope of this project the goal was accomplished. Utilizing the directional control valve to achieve a hydraulic brake function, has potential to be a solutionfor heavy mobile machinery in near future. However, further research and testing are required to be conducted on other heavy mobile machinery which have greater top speeds and load capabilities than the machinery used in this project.
14

Analysis of Evolutionary Algorithms in the Control of Path Planning Problems

Androulakakis, Pavlos 31 August 2018 (has links)
No description available.
15

Bilevel Equalizer Drivers for Large Lithium-Ion Batteries

Sharma, Kripa 06 September 2019 (has links)
No description available.
16

Utveckla en affärsmodell inom open-loop supply chain för sällanköpsvaror : En kvalitativ flerfallsstudie gjord genom undersökning av mellanhandens roll i försörjningskedjan / Develop a business model within an open-loop supply chain for durable goods

Strandberg, Axel, Olsen, Oskar, Eckervad, Tobias January 2023 (has links)
Background: In the recents decades, one of humanity's biggest challenges has been the climatecrisis where emissions of greenhouse gases are the main problem. This has forced companies toact more environmentally friendly due to laws and regulations but also due to customer demand.Circular economy has become a hot topic with various definitions. One of the definitions isopen-loop supply chain and this essay will focus on explaining the concept of open-loop supplychain. Research question: 1. What can a business model look like for an intermediary for reusable durable goods in anopen-loop supply chain? 2. What challenges exist within reuse of durable goods between suppliers and intermediaries inan open-loop supply chain? Purpose: The purpose of this essay is to, through a multiple case study, develop a businessmodel on how intermediaries for reusable durable goods can work with an open-loop supplychain and how it can be applied in future industries. Method: Primary data through semi-structured interviews and secondary data through scientificarticles. Conclusion: The essay developed a business model for intermediaries for reusable durablegoods in an open-loop supply chain which is applicable to other industries. The essay alsodefined some of the challenges for intermediaries operating in an open-loop supply chain whichare transaction costs, building relationships, loss of control and long transportations. Furthermorethe level of relevance of these challenges depends on the amount of responsibility theintermediary has taken upon itself.
17

Analysis of a Small-Signal Model of a PWM DC-DC Buck-Boost Converter in CCM

Lee, Julie JoAnn 12 September 2007 (has links)
No description available.
18

Mobile robot for search and rescue

Litter, Jansen J. January 2004 (has links)
No description available.
19

Design and Control of a Cable-Driven Sectorial Rotary Actuator for Open-Loop Force Control

Neal, Jordan Downey 16 October 2015 (has links)
This thesis focuses on the detailed design, implementation, and testing of a unique high performance rotary actuator for use in a custom haptic force feedback device. This six degree of freedom (DoF) position input and three DoF force output haptic device is specifically designed to recreate force sensations with the goal of improving operator performance in remote or simulated environments. By upholding the strict design principles of an ideal force-source actuator, the developed actuator and consequently the haptic controller can successfully replicate forces accurately and realistically. In the comprehensive presentation of this design, numerous analytical tools are also developed and presented with the intention of them being resourceful in the design or improvement of other haptic actuators, specifically cable-driven force feedback designs. These tools which include a linear system model can be valuable not only in the development but in the control of cable-driven actuators. Due to the imposed design criteria, the developed 1.045 Nm (1.359 Nm peak) cable-driven sectorial rotary actuator exhibits numerous properties that are desired in an open-loop force controlled actuator. These properties include low inertia (6.53e-04 kgm^2), low perceived mass (0.102 kg), small torque resolution (3.84e-04 Nm), small position resolution (21.5 arcsec), and high bandwidth (300 Hz). Due to the efficient cable transmission the design is also backdrivable, isotropic, low friction, and zero backlash. As a result of these numerous intrinsic properties, a high fidelity force feedback haptic actuator was conceived and is presented in this thesis. / Master of Science
20

An Invertible Open-Loop Nonlinear Dynamic Temperature Dependent MR Damper Model

Jumani, Sajit Satish 10 June 2010 (has links)
A Magnetorheological damper is a commonly used component in semi-active suspensions that achieves a high force capacity and better performance than a passive system, without the added expense and power draw of a fully active system, all while maintaining failsafe performance. To fully exploit the capabilities of an MR Damper, a high fidelity controller is required that is simple and easy to implement, yet does not compromise the accuracy or precision needed in many high-performance applications. There is a growing need for this level of operation, and this proposed work addresses these requirements by creating an empirically derived invertible model that enables the development of more accurate command signals by capturing the effect of temperature on a MR Damper's performance capabilities. Furthermore, this solution is specifically tailored for real-time application and does not require force feedback. Thus it requires low computation power and minimizes end-user cost by eliminating the need for additional high cost sensors such as load cells. A notable observation that resulted from the development of this proposed model was the difference in behavior between on and off states. Additionally a unique behavior was recognized with respect to the transition between high speed and low speed damping. For validation, the proposed model was compared against experimental data as well as an industry standard Spencer model; it produced excellent results in both cases with minimal error. / Master of Science

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