• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 13
  • 3
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 30
  • 30
  • 11
  • 9
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 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

Development of a Weight Control System for Ship Construction

Tsao, Jui-lin 24 June 2005 (has links)
It is a vitally important task to achieve control of the weight and center of gravity of lightship during building a new ship. If the lightship weight is slightly out of control, the deadweight inadequacy and a deviation from the initial design target will be caused. The basic performance and function of a ship at sea are also resulted. Furthermore, if the lightship weight is incompletely under control, it will bring about an unsafe vessel, ship-delivery difficulty and a severe loss for shipbuilder. Docking arrangement is optimized to allocate by using the state-of-the-art finite element method to analyze the lightweight distribution as the load and the ship girder as a beam; in addition, the dock is recognized as a spring-liked elastic foundation subjected to compression only. It is verified by comparison between measurement of the lightship weight by means of the weight control system on land and the traditional inclining experiment. Based on the results, it can be shown that the whole system is reliable, available and efficient. The load cell is utilized as a component of the weight control system to measure the compressive force (i.e., ship weight) at a specified dock. The main function of the system is to determine the lightweight and its C.G. on-land construction instead of the time-consuming and labor-wasting traditional way. The presented methodology will be beneficial for weight control of a new-ship building in the future.
2

In situ calibration for load cells in bipedal 3D printed robot utilizing Computer-Aided Design model

Le, Tung Xuan 07 August 2023 (has links)
Load cells are very important components in a robot system. They help the robot to get feedback from the environment around it and generate control signals accordingly. However, like every other sensor, load cells need to be calibrated over time to maintain their accuracy and precision. In the current method, they need to be detached from the robot. Then known weights are hung below the load cells to get the raw signal from the load cells. These two types of values will then be used to generate the equations that convert the raw signal to the force values. This is a challenge as not many robots are maintenance-friendly so detaching the load cells can take a lot of time, not to mention the process can damage the load cells if not conducted carefully. This research project utilizes mechanical simulation to calculate the known force values acting on the load cells without taking them out of the robot system. Then these force values are used for the calibration process. In this thesis, the in situ calibration method will be conducted on the actuator-controlled pendulum, and a bipedal robot when it is hanging on the gantry and standing on the ground. Also, since mechanical simulation requires a lot of computational power, a geometry simplification method will also be introduced so this in situ calibration method can be used for ordinary personal computers. The results show that the new calibration method is easy to work with, the force values still meet the requirements for calibration, and the computer only needs 10-12 seconds to run each simulation. / Master of Science / A robotic system usually need the load cell to generate the correct control signal. However, the load cell needs to be calibrated over time for maintenance. The current calibration method requires the load cell to be detached from the robot so the user can apply known forces to the load cell. This thesis introduces an in situ calibration method that can calculate forces that are applied to the load cell so the user does not need to detach the load cell from the robot. An optimization method is also introduced to make the calibration process can be done on an ordinary personal computer.
3

Development of a Safeguards Monitoring System for Special Nuclear Facilities

Henkel, James Joseph 01 August 2011 (has links)
Two important issues related to nuclear materials safeguards are the continuous monitoring of nuclear processing facilities to verify that undeclared uranium is not processed or enriched and to verify that declared uranium is accounted for. The International Atomic Energy Agency (IAEA) is tasked with ensuring special nuclear facilities are operating as declared and that proper material safeguards have been followed. Traditional safeguards measures have relied on IAEA personnel inspecting each facility and verifying material with authenticated instrumentation. In newer facilities most plant instrumentation data are collected electronically and stored in a central computer. Facilities collect this information for a variety of reasons, most notably for process optimization and monitoring. The field of process monitoring has grown significantly over the past decades, and techniques have been developed to detect and identify changes and to improve reliability and safety. Several of these techniques can also be applied to international and domestic safeguards. This dissertation introduces a safeguards monitoring system developed for both a simulated Uranium blend down facility, and a water-processing facility at the Oak Ridge National Laboratory. For the simulated facility, a safeguards monitoring system is developed using an Auto-Associative Kernel Regression model, and the effects of incorporating facility specific radiation sensors and preprocessing the data are examined. The best safeguards model was able to detect diversions as small as 1.1%. For the ORNL facility, a load cell monitoring system was developed. This monitoring system provides an inspector with an efficient way to identify undeclared activity and to identify atypical facility operation, included diversions as small as 0.1 kg. The system also provides a foundation for an on-line safeguards monitoring approach where inspectors remotely facility data to draw safeguards conclusion, possibly reducing the needed frequency and duration of a traditional inspection.
4

Estimating the relation between vertical ground reaction force and heart rate during treadmill running

Kuo, Fu-Chang 20 July 2012 (has links)
Treadmill is a highly popular fitness equipments. One of the most important purposes of running is to consume redundant energy of the body. A well designed exercise intensity plan can achieve the benefits of exercise while avoiding sport injuries. Calculating the appropriate exercise intensity is therefore a valuable study issue. Current commercially available treadmills cannot provide sufficient physiological data. In particular, in order to measure the ground reaction force (GRF) of the runners, traditional approach is to design treadmill as a rigid body. Such treadmills are thus expensive and heavy. To estimate heart rate (HR), ECG measurement is typically required. However, sweat can cause the patch to loose and the quality of the signal transmission can also be degraded by environmental noises. Thus the aim of this work is to develop a simple and effective method to assess exercise intensity by estimating HR with GRF.. To achieve this goal, this work places load cells under the legs of the treadmill. By constructing the dynamic model of the treadmill via system identification technique, we can estimate the actual GRF from the measurements of the load cells. After computing the TVI (Total Vertical Impulse) index from the GRF, this work then investigates the linear relationship between TVI and running energy consumption by estimating HR from TVI. Based on the known relationship between HR and exercise intensity, we can observe the runner¡¦s condition from the speed of HR recovery and the HR time response during running. By means of linear regression method, it is found that the linear relations between TVI index and these HR measures are statistically significant. The p-value of such statically tests become even smaller when TVI index is normalized.
5

CONSIDERATIONS FOR USING THE DYNAMIC INERTIA METHOD IN ESTIMATING RIGID BODY INERTIA PROPERTY

LAZOR, DANIEL R., Jr. 06 October 2004 (has links)
No description available.
6

Options for providing quality axle load data for pavement design

Wood, Steven 30 March 2017 (has links)
This research evaluates four options to produce quality axle load data for pavement design: piezoelectric WIM sites (corrected and uncorrected data), static weigh scales, and a piezo-quartz WIM site. The evaluation applies four data quality principles: data validity, spatial coverage, temporal coverage, and data availability. While all principles are considered, the research contributes in the development and application of an integrated and sequential approach to assess data validity of the options by performing analyses to determine the precision and accuracy of axle load measurements. Within the context of Manitoba, the evaluation reveals that data produced by piezo-quartz and static weigh scales have superior validity, with piezo-quartz data offering better temporal coverage, data availability, and future geographic coverage. Ultimately, the selection of the best option for providing quality axle load data depends on the relative importance of data quality principles for producing data supporting sound pavement designs and infrastructure management decisions. / May 2017
7

DEVELOPMENT OF A FORCE SENSING INSOLE TO QUANTIFY IMPACT LOADING TO THE FOOT IN VARIOUS POSTURES / A FORCE SENSING INSOLE TO QUANTIFY IMPACT LOADING TO THE FOOT

Van Tuyl, John T. January 2014 (has links)
Lower leg injuries commonly occur in both automobile accidents and underbody explosive blasts, which can be experienced in war by mounted soldiers. These injuries are associated with high morbidity. Accurate methods to predict these injuries, especially in the foot and ankle, must be developed to facilitate the testing and improvement of vehicle safety systems. Anthropomorphic Test Devices (ATDs) are one of the tools used to assess injury risk. These mimic the behavior of the human body in a crash while recording data from sensors in the ATD. Injury criteria for the lower leg have been developed with testing of the leg in a neutral posture, but initial posture may affect the likelihood of lower leg injury. In this thesis, the influence of initial posture on key injury assessment criteria used in crash testing with ATDs was examined. It was determined that these criteria are influenced by ATD leg posture, but further work is necessary to determine if the changes in outcome correspond to altered injury risk in humans when the ankle is in the same postures. In order to better quantify the forces acting on various areas of the foot and correlate those with injury, allowing for development of new criteria, a purpose built force sensor was created. An array of these sensors was incorporated into a boot and used to instrument an ATD leg during impact testing. The sensors provided useful information regarding the force distribution across the sole of the foot during an impact. A numerical simulation of the active material in the sensor was also created to better understand the effect of shear loading on the sensor. This work furthers the understanding of lower leg injury prediction and develops a tool which may be useful in developing accurate injury criteria for the foot and lower leg. / Thesis / Master of Applied Science (MASc) / This work investigates how the posture of the lower leg of a crash test dummy can influence the interpretation of crash test results. A tool was created to measure forces acting on the foot during testing. The force measurement uses a material which changes resistance when it is compressed.
8

Preliminary Design of an Improved Load Measuring Device for Underground Mining Standing Supports

Stables, Brandon Shane 30 November 2021 (has links)
Standing support is often used in conjunction with underground retreat mining. Knowledge of the load-displacement behavior of a standing support and loading induced by the mine opening is critical proper support selection. The NIOSH STOP database contains load-displacement laboratory test data for most commonly used standing supports. Hydraulic load cells currently used to measure in-situ loading of standing supports have exhibited leakage under load, producing irregularities within the dataset. An improved hydraulic load cell eliminates leakage and produces more consistent data. / Master of Science / In retreat mining of a traditional room and pillar or longwall mining operation standing support is utilized. The standing support is comprised over various types of systems, wood timbers, wood cribs, pumpable supports and metal supports. These standing supports help aid in the recovery of the reserves and/or maintain ventilation through the mining excavation. National Institute for Occupational Safety and Health (NIOSH) Support Technology Optimization Program (STOP) has a database of laboratory testing on load displacement used on various standing supports. To relate this laboratory testing to in-situ load of standing support hydraulic load cells have been introduced. The hydraulic load cells design is a thin metal bladder filled with fluid that is placed on the top or bottom of the standing support. These hydraulic load cells have exhibited inconsistencies due to leakage under load, producing irregularities within the dataset. To achieve a reliable dataset on active standing supports it is vital that current load-measuring devices needs to be re-evaluated and redesigned.
9

TEMPORAL VARIABILITY OF RIVERBED HYDRAULIC CONDUCTIVITY AT AN INDUCED INFILTRATION SITE, SOUTHWEST OHIO

Birck, Matthew D. 04 August 2006 (has links)
No description available.
10

Wind Tunnel Testing of a Variable Camber Compliant Wing with a Unique Dual Load Cell Test Fixture

Zientarski, Lauren Ann January 2015 (has links)
No description available.

Page generated in 0.0531 seconds