Mechanical Engineering Commons^™

A New Autonomous Underwater Vehicle For Imaging Research, C. Roman, O. Pizarro, R. Eustice, H. Singh

Christopher N. Roman

Currently, unmanned underwater vehicles either tend to be cumbersome and complex to run, or operationally simple, but not quite suitable platforms for deep water imaging. This paper presents an alternative design in the form of a new low cost and easier to use autonomous underwater vehicle (AUV) for imaging research. The objective of the vehicle is to serve as a readily available and operationally simple tool that allows rapid testing of imaging algorithms in areas such as photomosaicking, 3D image reconstruction from a single camera, image based navigation, and multi-sensor fusion of bathymetry and optical data. These are all current …

Fluid Flow In Micro-Channels: A Stochastic Approach, Hilda Marino Black

Doctoral Dissertations

In this study free molecular flow in a micro-channel was modeled using a stochastic approach, namely the Kolmogorov forward equation in three dimensions. Model equations were discretized using Central Difference and Backward Difference methods and solved using the Jacobi method. Parameters were used that reflect the characteristic geometry of experimental work performed at the Louisiana Tech University Institute for Micromanufacturing.

The solution to the model equations provided the probability density function of the distance traveled by a particle in the micro-channel. From this distribution we obtained the distribution of the residence time of a particle in the micro-channel. Knowledge of …

Design Of Adaptive Sliding Mode Fuzzy Control For Robot Manipulator Based On Extended Kalman Filter, Abdelrahman Aledhaibi

Mechanical & Aerospace Engineering Theses & Dissertations

In this work, a new adaptive motion control scheme for robust performance control of robot manipulators is presented. The proposed scheme is designed by combining the fuzzy logic control with the sliding mode control based on extended Kalman filter. Fuzzy logic controllers have been used successfully in many applications and were shown to be superior to the classical controllers for some nonlinear systems. Sliding mode control is a powerful approach for controlling nonlinear and uncertain systems. It is a robust control method and can be applied in the presence of model uncertainties and parameter disturbances, provided that the bounds of …

Advances In Fusion Of High Resolution Underwater Optical And Acoustic Data, H. Singh, C. Roman, L. Whitcomb, D. Yoerger

Christopher N. Roman

We report efforts to merge data from the complementary modalities of optical and acoustic sensing for obtaining more accurate representations of the seafloor. We show that the principal obstacles to merging the acoustic and optical imaging modalities are the distortions inherent to each modality. The construction of geometrically accurate photomosaics is dominated by incremental errors arising as individual images are scaled and warped to form the photomosaic. For microbathymetric mapping, principal errors arise from sensor position and orientation calibration parameters that affect our ability to construct maps from sonar data that are commensurate with sensor and navigation resolution. We show …

A Hybrid Finite Element-Finite Difference Method For Thermal Analysis In A Double-Layered Thin Film, Teng Zhu

Doctoral Dissertations

Thin film technology is of vital importance in microtechnology applications. For instance, thin films of metals, of dielectrics such as SiO2, or Si semiconductors are important components of microelectronic devices. The reduction of the device size to the microscale has the advantage of enhancing the switching speed of the device. The reduction, on the other hand, increases the rate of heat generation that leads to a high thermal load on the microdevice. Heat transfer at the microscale with an ultrafast pulsed-laser is also a very important process for thin films. Hence, studying the thermal behavior of thin films or of …

Diffusion Problems In Wound Healing And A Scattering Approach To Immune System Interactions, Julia Suzanne Arnold

Mathematics & Statistics Theses & Dissertations

A theoretical model for the existence of a Critical Size Defect (CSD) in certain animals is the focus of the majority of this dissertation. Adam [1] recently developed a one-dimensional model of this phenomenon, and chapters I–V address the exist the CSD in a two-dimensional model and a three-dimensional model. The two dimensional (or 1-d circular) model is the more appropriate for a study of CSD's. In that model we assume a circular wound of uniform depth and develop a time-independent form of the diffusion equation relevant to the study of the CSD phenomenon. It transpires that the range of …

Topography-Induced Contributions To Friction Forces Measured Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan

Sriram Sundararajan

Most friction studies using an atomic force/friction force microscope, while concentrating on material-induced effects, often present users with conflicting and confusing interpretations of the topography-induced friction forces. It has been generally reported that topography-induced contributions are independent of scanning direction and can be removed by subtracting friction data from forward and backward scans. In this article, we present friction studies on samples with well-defined topography variations and find that the above-given statement is not generally true. At surface locations involving significant changes in topography, the topography-induced contributions to friction forces are found to be different between forward and backward scanning …

Theoretical And Experimental Study Of Generation Mechanisms For Laser Ultrasound In Woven Graphite /Epoxy Composites With Translaminar Stitching, Adam D. Friedman

Dissertations, Theses, and Masters Projects

The aerospace industry is beginning to use advanced composite materials for primary load bearing structures and their failure mechanisms must be better understood to predict their behavior in service. The Combined Loads Tests (COLTS) facility is being constructed at the NASA Langley Research Center to characterize these failure mechanisms. Laser based ultrasonic NDE can monitor the samples during dynamic loading without interfering with the structural tests. However, the constraints of implementing laser ultrasound in a structures laboratory reduces the efficiency of the technique. The system has to be "eye-safe" because many people will be present during the structural tests. Consequently, …

Rotary Honing: A Variant Of The Taylor Paint-Scraper Problem, Christopher Hills, H. Moffatt

Articles

The three-dimensional Row in a corner of fixed angle α induced by the rotation in its plane of one of the boundaries is considered. A local similarity solution valid in a neighbourhood of the centre of rotation is obtained and the streamlines are shown to be closed curves. The effects of inertia are considered and are shown to be significant in a small neighbourhood of the plane of symmetry of the flow. A simple experiment confirms that the streamlines are indeed nearly closed; their projections on planes normal to the line of intersection of the boundaries are precisely the 'Taylor' …

Electroanalysis Using Differential Pulse Methods And Stripping Techniques., Enda Howard

Masters

Application of a differential pulse waveform to a microelectrode or a rotating disk electrode results in a peaked response for amperometric redox reactions. Based on these observations models were proposed and tested for these methods. Simulations of the models were carried out by inputting the relevant equations into Microsoft Excel. The microelectrode study revealed a good correlation between one model and the numerical derivative of the current following a linear sweep potential waveform. Experimentally the derivative can be obtained numerically following a linear sweep. The alternative differential pulse waveform requires more sophisticated equipment and the response can be affected by …

Structural And Electrical Characterization Of A Novel Mixed Conductor: Ceo2 - Sm2O3 - Zro2 Solid Solution, W. Huang, P. Shuk, M. Greenblatt, M. Croft, Fanglin Chen, M. Liu

Faculty Publications

solid solutions were synthesized for the first time by the hydrothermal method. The electrical properties of the solid solutions have been studied in air and under reducing conditions. Solid solutions with the fluorite structure were formed in all of the studied range of substitution after calcination at 1500°C. With increasing substitution up to 30 mol %, the electronic conductivity increases under a reducing atmosphere. The solid solution has good mixed electronic and ionic conductivity; the total conductivity is 0.42 S/cm at and 700°C with an estimated ionic conductivity of ca. .

Test 1769: White 6410, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1769: Agco Lt70 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Nebraska Summary 333: Agco Dt160 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Nebraska Summary 334: Agco Dt180 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1780: White 6810 Diesel 32-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 1778: John Deere 8410t And 8420t Diesel 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 1768: Agco Allis 8765 Diesel 12-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 1788: John Deere 7710 Powrquad Diesel 20-Speed (Chassis S/N Rw7710h030004 And Higher), Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 1782: White 8610 Diesel 18-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 1930: Case Ih Mx 80c Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1769: Agco Allis 8745 Diesel (Cummins Engine), Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1783: Case Ih Stx 375/New Holland Tj 375 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1785: Case Ih Stx 440 Quadtrac/Case Ih Stx 450 Quadtrac Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1784: Case Ih Stx 440/Case Ih Stx 450/New Holland Tj 450 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1942: New Holland 9684 Quadrasync Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1784: Case Ih Stx 440/Case Ih Stx 450/New Holland Tj 450 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1783: Case Ih Stx 375/New Holland Tj 375 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1929: Case Ih Mx 90c Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1918: New Holland Tm125 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.