Engineering Commons^™

Clustered-Dot Periodic Halftone Screen Design And Icc Profile Color Table Compression, Chuohao Tang

Open Access Dissertations

This dissertation studies image quality problems associated with rendering images in devices like printing or displaying. It mainly includes two parts: clustered-dot periodic halftone screen design, and color table compression.

Screening is a widely used halftoning method. As a consequence of the lower resolution of digital presses and printers, the number of printer-addressable dots or holes in each microcell may be too few to provide the requisite number of tone lev- els between paper white and full colorant coverage. To address this limitation, the microcells can be grouped into supercells. The challenge is then to determine the desired supercell shape …

Computational Investigation Of Force Generation, Relaxation, And Remodeling Of The Actin Cytoskeleton, Wonyeong Jung

Open Access Theses

Diverse mechanics of the F-actin cytoskeleton mediate essential behaviors of cells, including cell division, migration, and shape change. Force generation by motor proteins and the resultant morphological change of cytoskeletal networks govern cellular processes such as migration and division. Cell stiffening and softening under external mechanical stimuli regulate cell shape. In this thesis, interplay between various cytoskeletal components during these processes is investigated using an agent-based computational model to elucidate mechanical factors underlying these processes. This thesis is composed of three independent studies.

First, force generation in cortical actomyosin networks is studied. Using the computational model, the effects of motor …

Early Bearing Fault Analysis Using High Frequency Enveloping Techniques, Ilya Shulkin

Open Access Theses

High frequency acceleration enveloping is one of many tools that vibration analysts have at their disposal for the diagnosis of bearing faults in rotating machinery. This technique is believed to facilitate very early detection of potential failures by detecting low amplitude repetitive impacts in frequency ranges above conventional condition monitoring. One traditional enveloping method uses a mathematical operation known as the Hilbert transform along with other signal processing procedures such as band-pass filtering and full-wave rectification. For comparison, another method uses a proprietary algorithm included in National Instruments’ LabVIEWTM add-on package: Sound and Measurement Suite. Enveloping’s inherent problem with noise …

Investigation Of Thin Film Thermal Transport Using Micro-Raman Thermometry And Tip Enhanced Raman Spectroscopy, Mithun Srinivasan

Open Access Theses

In recent years, a steady increase in the need for packing more energy in smaller devices had driven the need for better understanding of thermal transport in thin films and designing methods to manipulate them. This can be attributed as the reason for numerous efforts made in the past decade to achieve temperature resolution at nanoscale. Such techniques can help us in understanding the thermal conductivity of thin films which can result in an improved performance of these devices. The temperature probing technique must be non-invasive to avoid damaging the vulnerable thin films, fast to study the energy transport and …

Uncertainty Quantification On Industrial High Pressure Die Casting Process, Jiahong Fu

Open Access Theses

High pressure die casting (HPDC) is a famous manufacturing technology in industry. This manufacturing process is simulated by commercial code to shed the light on the quality of casting product. The casting product quality might be affected by the uncertainty in the simulation parameter settings. Thus, the uncertainty quantification on HPDC process is significant to improve the casting quality and the manufacturing efficiency.

In this work, three uncertainty quantifications and sensitivity analyses on the A380 aluminum alloy HPDC process of intermediate speed plate are performed. The material thermophysical properties, boundary conditions of the model, and operational as well as artificial …

A High-Performance Communication Topology For Decentralized Protocols, Raza A. Khan

Open Access Theses

Preserving transaction atomicity and ensuring its commitment is key to the maintenance of data integrity in a distributed database. The distributed consensus protocol is a prominent example of a mechanism used to accomplish safe commitment of a distributed transaction. These protocols are based primarily on repeated message exchange among all sites/nodes and their performance is characterized not only by the number of these messages but also by the underlying communication topology. This thesis proposes a measure of performance known as average message complexity and proposes a communication structure based on folded even graphs called the Folded Even Network (FEN). Performance …

Effect Of Temperature On Deep Lined Circular Tunnels In Isotropic And Transversely Anisotropic Elastic Ground, Fei Tao

Open Access Theses

A tunnel is a passageway constructed through soil or rock. It is one of the most important underground structures and has been widely used in transportation. Much research has been done on tunnel performance and on the interaction between ground, excavation, liner installation and support. The work has provided a better understanding of the interplay that exists between deformations and stresses transferred from the ground to the support. Significant insight into the problem has been provided by closed-form analytical solutions. A number of analytical formulations have been obtained for underground openings and lined tunnels under different scenarios, namely shallow or …

Design And Analysis Of A High Performance Valve, Jordan M. Garrity

Open Access Theses

Most valves available in the fluid power industry today are capable of achieving either a large flow rate or a quick response time; however, often they are unable to deliver both simultaneously. Commercially available valves that can produce both at the same time require complex geometries with multiple actuation stages and piloting pressures, making them expensive components. To establish their active usage in applications across the fluid power industry, a reduction in price for these components is paramount. The Energy Coupling Actuated Valve (ECAV) is capable of solving the large flow rates with fast actuation speeds trade-off by utilizing a …

Phase Field Damage Simulations Of Debonding Between Matrix And Spherical Inclusions, Johanna B. Palsdottir

Open Access Theses

Polymer-bonded explosives (PBX) are complicated composites, and it is important for practical applications to know how they deform and fracture. PBX consists of large volume fraction of energetic particles and experiments show that the interface is a critical region for structural stability since particles are often weakly bonded to the polymer and cracks initiate there and the composite fractures. This study focuses on the interface between a particle and a binder and how the particle inclusion starts to debond from the polymer binder in compressive and tensile loading.

A phase field damage model is used to model the response of …

Control-Oriented Modeling, Validation, And Analysis Of A Natural Gas Engine Architecture, Chaitanya Panuganti

Open Access Theses

In order to improve performance and meet increasingly tight emissions regulations, engine manufacturers must improve algorithms used to control the engine. One possible strategy is to utilize centralized control algorithms that take into account the coupled interactions between inputs and outputs. Implementing a centralized control strategy often requires some kind of dynamic model of the system, which is a primary motivation for modeling efforts in this thesis. In a methodical fashion, this thesis derives a control model for a natural gas engine architecture and validates this control model against reference data in simulation. Additionally, this thesis performs control-oriented analysis on …

Magnetic Equivalent Circuit Based Permanent Magnet Characterization, Vinicius Cabral Do Nascimento

Open Access Theses

This thesis sets forth a permanent magnet characterization fixture and procedure. The work begins with a review of the state of the art in permanent magnet characterization. It then sets forth a new characterization fixture. The proposed system relies on the use of low cost sensors to perform the necessary measurements, which consists of search coils, hall sensors, and current probes. A magnetic equivalent circuit is set forth to analyze the fixture and for use in identification of permanent magnet parameters. The characterization procedure is based on an experimentally defined magnetic equivalent circuit. An experimental approach to model the tester …

Fabrication And Drying Of Cnc-Based Microcapsules With Pdms/Antimicrobial Oil Cores Via The Microcapillary Device, Yunze Dai

Open Access Theses

Cellulose nanocrystals (CNC) which are the crystalline regions of elementary microfibrils found in cellulose are becoming a promising biocompatible nanoscale building block. We report on the generation, evolution, and drying of CNC capsules with oil cores, obtained from double emulsion drops. Microcapillary devices were used to generate the double emulsion drops with outer diameters ranging from 75 to 225 µm, and shell thicknesses ranging from 5 to 60 µm. 10 wt% aqueous CNC suspensions without and with the addition of PEGDA, a UV-crosslinkable binder, were used as the shell material while 10 cSt PDMS oil was used in the core. …

Characterization Of A Continuous-Flow Reactor For Solar Uv Water Disinfection, Margaret M. Busse

Open Access Theses

Lack of access to safe water is a common problem in many developing countries (UNICEF/WHO, 2011). Fortunately, solar ultraviolet (UV) radiation is abundantly available in many of these same areas, and it has been used to accomplish disinfection of drinking water by processes that involve no electrical power, such as solar water disinfection (SODIS). However, conventional SODIS systems are limited by batch processing and exclusion of UVB radiation, which is the most germicidally-active portion of the UV spectrum (Coohill and Sagripanti, 2008). To address these limitations, a continuous-flow solar UV disinfection system was developed to amplify ambient solar UV radiation, …

Techniques And Technologies For Decontaminating Chemically Contaminated Premise Plumbing Infrastructure, Karen S. Casteloes

Open Access Theses

Recent large-scale drinking water chemical contamination incidents in Canada and the U.S. have affected more than 1,000,000 people. In all cases premise plumbing has become contaminated and disparate plumbing decontamination approaches have been applied. Premise plumbing components include the service line and piping within the building as well as various appurtenances (i.e., tanks, valves, fixtures). The overall research goal was to identify techniques and technologies that can be used for premise plumbing decontamination. To achieve this goal two separate studies were conducted and are presented as two independent thesis chapters.

The study described in Chapter 1 was designed to understand …

Targeted Products From Fast-Hydropyrolysis And Hydrodeoxygenation Of Biomass, Ian Tad Smith

Open Access Theses

Previously, the H2Bioil process was proposed as a possible way to convert sustainably available intact biomass into liquid fuels. The optimization of this process and possible synergies with other biomass conversion processes are presented in this thesis.

The selectivity of the PtMo hydrodeoxygenation catalyst was tuned using two different hydrogen partial pressures: 25 bar, and 2.5 bar. This effect was studied on cellulose and intact biomass samples to determine the effect that hydrogen has upon the retention of aromatic compounds found in intact biomass. These experiments show that it is possible for the hydrogenation activity of the PtMo catalyst to …

Dynamic Triaxial Compression Experiments On Borosilicate And Soda-Lime Glass, John T. Chojnacki

Open Access Theses

A series of compression experiments were performed on borosilicate and soda-lime glass using a triaxial compression Kolsky bar. The triaxial compression Kolsky bar differs from a traditional Kolsky bar by having two pressure chambers, one enclosing the specimen and the other enclosing the end of the transmission bar, so that a specimen may be pre-stressed axially and radially before a dynamic axial load is applied. The result is a modified Kolsky bar capable of measuring axial deformation and axial stresses of a specimen at various strain rates under a range of confinement pressures. Borosilicate glass was subjected to triaxial confinement …