Engineering Commons^™

Preliminary Investigation Of Ultra-High Performance Concrete Behavior At High Strain Rates Using The Split-Hopkinson Pressure Bar, Jacob Clark

Dissertations, Master's Theses and Master's Reports - Open

Ultra-high performance concrete (UHPC) displays several enhanced material properties compared to normal strength concrete (NSC). In past research, Split-Hopkinson pressure bar (SHPB) tests have been used for normal strength concrete to determine material behavior at high strain rates. The behavior of advanced concrete materials, such as UHPC, under high strain rates has not been thoroughly investigated. While it is generally accepted that concrete materials experience increases in compressive strength under increasing strain rates, a preliminary investigation was conducted to gain insight into the compressive behavior of UHPC under high strain rate SHPB testing.

In this research, 50 specimens were tested …

Solving Logistic System Design Problem Considering Various Biomass Feedstock Using Two Metaheuristic Optimization Methods, Jesusita Ibarra

Open Access Theses & Dissertations

Bioenergy has become an important source of energy; it can be used as an alternative to fossil fuel energy, and it offers significant potential to alleviate climate change by reducing greenhouse gas emissions caused by the burning of fossil fuels. The Energy Independence and Security Act decrees the use of 21 billion gallons of advanced biofuel including 16 billion gallons of cellulosic biofuels by the year 2022. It is easy to observe that biomass can make a considerable contribution meet the energy demands. On the other hand, the supply of sustainable energy is one of the main challenges that must …

A Quantitative Approach Using An Axiomatic Design Framework To A Medication Distribution System, Pepito Raguini

Open Access Theses & Dissertations

As the need to minimize medication errors drives many medical facilities to come up with robust solutions to the most common error that affects patient's safety, these hospitals would be wise to put a concerted effort into finding methodologies that can facilitate an optimized medical distribution system. If the hospitals' upper management is looking for an optimization method that is an ideal fit, it is just as important that the right tool be selected for the application at hand. In the present work, we propose the application of Axiomatic Design (AD), which is a process that focuses on the generation …

Purification Of Sodium Sulfate By Crystallization, Perla Teresita Torres

Open Access Theses & Dissertations

Sodium sulfate can be recovered from a dilute solution by concentrating it by conventional water treatment techniques like reverse osmosis and electrodialysis; however, those processes also concentrate impurities like arsenic. The sodium sulfate would have commercial use if it can be recovered in an arsenic-free form. This study demonstrated that sodium sulfate could be separated from impurities using slow cooling crystallization in a novel apparatus developed and designed during the experimentation. This device is called a heat exchanger crystallizer and allows slow cooling crystallization in order to grow pure crystals of sodium sulfate decahydrate. Crystals grown in the heat exchanger …

Investigation Into The Operation And Safety Of Freeway Auxiliary Lanes: Towards Uniform Design Guidelines, Yubian Wang

Open Access Theses & Dissertations

Freeways operate closest to the purest form of uninterrupted traffic flow. There is no constant interruption to traffic flow (such as stop sign and traffic signal), and access is limited to ramp locations. Therefore, at freeways, bottlenecks, if exist, are usually caused by merging and diverging traffic at ramp locations. Bottleneck removal at freeway ramp areas can reduce average freeway commuter delay. Currently, engineers may add auxiliary lanes at ramp areas to mitigate or remove bottlenecks.

The American Association of State Highway Transportation Officials (AASHTO) publication A Policy on Geometric Design of Highways and Streets, commonly known as the "Green …

Reducing Metal Alloy Powder Costs For Use In Powder Bed Fusion Additive Manufacturing: Improving The Economics For Production, Fransisco Medina

Open Access Theses & Dissertations

Titanium and its associated alloys have been used in industry for over 50 years and have become more popular in the recent decades. Titanium has been most successful in areas where the high strength to weight ratio provides an advantage over aluminum and steels. Other advantages of titanium include biocompatibility and corrosion resistance. Electron Beam Melting (EBM) is an additive manufacturing (AM) technology that has been successfully applied in the manufacturing of titanium components for the aerospace and medical industry with equivalent or better mechanical properties as parts fabricated via more traditional casting and machining methods. As the demand for …

Crystal Structure, Phase, And Optical Properties Of Yttrium-Doped Hafnium Oxide Nanocrystalline Thin Films, Alejandro Ortega

Open Access Theses & Dissertations

Yttrium-doped hafnium oxide (YDH) nanocrystalline films were produced by sputter-deposition at various substrate times and temperatures, to produce YDH films in a wide range of thicknesses, dYDH∼25 to 1100 nm. The deposition was made onto optical grade quartz and sapphire substrates. Samples deposited on sapphire were subject to post-deposition annealing (PDA) at various times (3-24 hr) and temperatures (1100 - 1500 °C). The effect of d[special characters omitted]YDH on the crystal structure, surface/interface morphology and optical properties of YDH films was investigated. X-ray diffraction analyses revealed the formation of monoclinic phase for relatively thin films (<150nm). The evolution towards stabilized cubic phase with increasing dYDH [special characters omitted]is observed. The scanning electron microscopy results indicate the dense, columnar structure of YDH films as a function of dYDH. Spectrophotometry analyses indicate that the grown YDH films are transparent and exhibit interference fringes. The band gap was found to be ∼ 5.60 eV for monoclinic YDH films while distinct separation and an increase in band gap to 6.03 eV is evident with increasing dYDH and formation cubic YDH films. The PDA films band gaps were found to be between 5.31 and 5.72 eV, all of which exhibit secondary gaps. A correlation between growth conditions, annealing, phase evolution, and optical properties of the YDH nanocrystalline thin films is established.

The Standardization Of Printable Materials And Direct-Write Systems, Jessica Lynn Porras

Open Access Theses & Dissertations

The standardization of Printable Materials and Direct-Write Systems addresses the many areas of Printing Nano Engineering that lack standards. Printing Nano Engineering is a new method of manufacturing electronics that utilize direct-write system with printing principles to manufacture electronic components.

Standards need to be developed for the different direct-write systems and printable materials in order to provide compatibility amongst printed electronics and to allow the optimization for direct-writ s e systems, and printable materials associated with these systems. There are many different types of direct-write systems in industry; each system involves different methods for printing that incorporates the limiting parameters …

Comparative Characterization Of Ni-Base Superalloys Fabricated By Laser And Electron Beam Melting Technologies, Krista Amato

Open Access Theses & Dissertations

Nickel-base superalloys have been used in cast and wrought, and powder metallurgy forms for nearly four decades for industrial and automotive applications. One drawback of cast alloys is that upon solidification, there is minimal microstructural control. Another issue to be improved is to eliminate the limitations of shapes and forms of fabricated alloys.

Rapid prototyping is a new technology of additive manufacturing that shows to be promising for the freeform fabrication of novel superalloys, including nickel-base alloys. New rapid manufacturing technologies allow us to produce parts in any shape that can be designed by computer-aided design (CAD) software. Additionally, the …

The Effect Of Gamma Radiation On Fibre Bragg Grating Sensors When Used As Radiation Dosimeters, Des Baccini

Theses : Honours

The effects of Gamma Radiation on Fibre Bragg Gratings (FBGs), when used as a radiation dosimeter, was proposed. The focus of this study centred on the FBG performance, and in particular the Bragg Wavelength Shift (BWS) whilst being exposed to ionizing radiation. Current research suggests that certain types of fibres manufactured by varying methods produce different results. The different responses to exposure from gamma irradiation between Germanium (Ge) doped optical fibres, with and without Hydrogen loading, along with the standard SMF-28 fibre with Hydrogen, were used and results noted and compared to previous work. The FBG’s in each fibre were …

Neutrosophic Emergencies And Incidences, Florentin Smarandache, Stefan Vladutescu

Branch Mathematics and Statistics Faculty and Staff Publications

No abstract provided.

Indeterminate Masses, Elements And Models In Information Fusion, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In this paper at the beginning, we make a short history of the logics, from the classical Boolean logic to the most general logic of today neutrosophic logic. We define the general logic space and give the definition of the neutrosophic logic. Then we introduce the indeterminate models in information fusion, which are due either to the existence of some indeterminate elements in the fusion space or to some indeterminate masses.

The best approach for dealing with such models is the neutrosophic logic, which is part of neutrosophy. Neutrosophic logic is connected with neutrosophic set and neutrosophic probability and statistics.

Nebraska Summary: S952 New Holland T5.95, 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 …

Nebraska Summary: S946 New Holland T4.95, 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 …

Nebraska Summary: S919 Challenger Mt475d, 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 …

A Robust Rgb-D Slam System For 3d Environment With Planar Surfaces, Po-Chang Su

Theses and Dissertations--Electrical and Computer Engineering

Simultaneous localization and mapping is the technique to construct a 3D map of unknown environment. With the increasing popularity of RGB-depth (RGB-D) sensors such as the Microsoft Kinect, there have been much research on capturing and reconstructing 3D environments using a movable RGB-D sensor. The key process behind these kinds of simultaneous location and mapping (SLAM) systems is the iterative closest point or ICP algorithm, which is an iterative algorithm that can estimate the rigid movement of the camera based on the captured 3D point clouds. While ICP is a well-studied algorithm, it is problematic when it is used in …

Investigation Of Cds Nanowires And Planar Films For Enhanced Performance As Window Layers In Cds-Cdte Solar Cell Devices, Jianhao Chen

Theses and Dissertations--Electrical and Computer Engineering

Cadmium sulfide (CdS) and cadmium telluride (CdTe) are two leading semiconductor materials used in the fabrication of thin film solar cells of relatively high power conversion efficiency and low manufacturing cost. In this work, CdS/CdTe solar cells with a varying set of processing parameters and device designs were fabricated and characterized for comparative evaluation. Studies were undertaken to elucidate the effects of (i) each step in fabrication and (ii) parameters like thickness, sheet resistance, light absorptivity solution concentration, inert gas pressure etc. Best results were obtained when the thickness of CdS planar film for the window layer was in the …

Copper Indium Diselenide Nanowire Arrays In Alumina Membranes Deposited On Molybdenum And Other Back Contact Substrates, Bhavananda R. Nadimpally

Theses and Dissertations--Electrical and Computer Engineering

Heterojunctions of CuInSe₂ (CIS) nanowires with cadmium sulfide (CdS) were fabricated demonstrating for the first time, vertically aligned nanowires of CIS in the conventional Mo/CIS/CdS stack. These devices were studied for their material and electrical characteristics to provide a better understanding of the transport phenomena governing the operation of heterojunctions involving CIS nanowires. Removal of several key bottlenecks was crucial in achieving this. For example, it was found that to fabricate alumina membranes on molybdenum substrates, a thin interlayer of tungsten had to be inserted. A qualitative model was proposed to explain the difficulty in fabricating anodized aluminum oxide …

Independent Component Analysis Enhancements For Source Separation In Immersive Audio Environments, Yue Zhao

Theses and Dissertations--Electrical and Computer Engineering

In immersive audio environments with distributed microphones, Independent Component Analysis (ICA) can be applied to uncover signals from a mixture of other signals and noise, such as in a cocktail party recording. ICA algorithms have been developed for instantaneous source mixtures and convolutional source mixtures. While ICA for instantaneous mixtures works when no delays exist between the signals in each mixture, distributed microphone recordings typically result various delays of the signals over the recorded channels. The convolutive ICA algorithm should account for delays; however, it requires many parameters to be set and often has stability issues. This thesis introduces the …

Test 2073: Case Ih Steiger 500 Quadtrac, 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 2061: Challenger Mt755d, 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 …

Evaluation Of Chemical Additives For The Separation And Recovery Of Bacteria From Food Matrices, Jennifer Leanne Frederick, Stephen P. Walker, Czarena L. Crofcheck, Melissa Newman, Frederick Payne

Biosystems and Agricultural Engineering Faculty Publications

The microbiological testing of foods is a well-established science. Due to the severity of foodborne pathogen illnesses, the widespread use and implementation of rapid detection methods in food testing labs is increasingly important. The first step for successful testing is sampling. Surfactants have been widely used in food microbiology, but there is not much, if any, published research about the use of fatty alcohols and chemical dispersants as aids in microbial separation and recovery. The microbial extraction efficiency of Escherichia coli K12 and Listeria innocua from three representative food matrices (hot dogs, spinach, and milk) was measured using chemical additives …

Antenna Designs For Wireless Medical Implants., Conor P. Conran

Masters

Active medical implants are devices that are surgically implanted inside the body. They have been developed to treat a wide range of ailments and many require some form of communications link with the outside world for maintenance and for remote medical diagnostics. Radio links promise a wide range of benefits over the traditional low frequency inductive coupling method.

Body tissue is a challenging environment, both for the device and for the radio signal that it transmits. Innovation in medical technology is creating a demand for high bandwidth links, and this in turn is driving the development of implantable antennas.

Many …

A New Simplified Federated Single Sign-On System, Chen Liang

Masters

The work presented in this MPhil thesis addresses this challenge by developing a new simplified FSSO system that allows end-users to access desktop systems, web-based services/applications and non-web based services/applications using one authentication process. This new system achieves this using two major components: an “Authentication Infrastructure Integration Program (AIIP)" and an “Integration of Desktop Authentication and Web-based Authentication (IDAWA)." The AIIP acquires Kerberos tickets (for end-users who have been authenticated by a Kerberos single sign-on system in one net- work domain) from Kerberos single sign-on systems in different network domains without establishing trust between these Kerberos single sign-on systems. The …

Modelling Of Bed Load Transport In The River Bandon, Stephen Falvey

Theses

This research thesis examines the various aspects of fluvial sediment transport with a particular emphasis on bed load transport. Sediment is a dynamic, essential and important part of Ireland’s river basins. The collection of sediment transport data is very important as it can help prevent flooding, improve water quality, protect ecology and assist cities and towns in future planning. At the moment there is no legislation dedicated exclusively to sediment but it does interface with a range of other pieces of legislation including the Water Framework Directive.

This literature review studies sediment transport. There is a particular emphasis on the …

Classification Of Irish Beaches To Determine Their Potential For Erosion, Aidan O'Connell

Theses

The objective of this literature review is to gather the relevant information regarding beach characteristics and beach erosion in order to undertake the project development stage of the thesis project. The background information that was reviewed was the different zones that are located on a beach; the functions of a beach and what most beaches are commonly used for; how beaches were formed; the legislation that is related to the beach or any work that is required to be carried out on a beach and some background information on the erosion of beaches.

The most relevant beach characteristics that impact …

Carbon Dioxide Absorption And Channelling In Closed Circuit Rebreather Scrubbers, Shona Cunningham

Theses

Closed Circuit Rebreathers (CCRs) are a type of Self Contained Underwater Breathing Apparatus (SCUBA) used predominantly by the diving community. CCR technologies have become prevalent within the commercial, military and technical diving communities over recent years. CCRs work by recycling breathing gas, by-passing the gas through a carbon dioxide (CO₂) chemical scrubber and topping the resultant scrubbed gas up with pure oxygen to maintain the oxygen content at a level which supports life. One of the main dangers currently faced by divers using this equipment is the risk of CO₂ poisoning if the scrubber fails. This failure …

The Potential For The Elimination Of Expansion Joints And Bridge Bearings From Existing Road Bridges In Ireland, Conor Keena

Theses

This research was focused on determining the feasibility of eliminating expansion joints and bridge bearings from existing short to medium span road bridges in Ireland. It is possible that this could provide a significant long-term economic benefit to bridge owners. A literature review was carried out as part of the research. This included investigations into research conducted in the areas of thermal movements of bridges, concrete creep and shrinkage, soil-structure interaction, lifetime costing, design standards and finite element analysis, and the elimination of bridge expansion joints in other countries.

Finite element analyses were carried out on two existing road bridges. …

The Design Of Moment Connections Between Rectangular Hollow Sections, Billy Allen

Theses

Steel portal frames in the construction industry typically comprise 1 and H sections. The design procedures for the connections in these frames (base, eaves and apex) are well established. This research is based on using rectangular hollow sections as the column and rafter members.

The eaves connection of a rectangular hollow section pitched portal frame is investigated in this report and includes a literature review of various experimental research relating to moment connections between rectangular hollow sections.

Three eaves joints were considered in this research. The joints were physically tested in the laboratory and a finite element analysis carried out. …

Application Of Nano-Imprint Lithography For Next Generation Carbon Nanotube-Based Devices, Svitlana Fialkova

Dissertations

This research report addresses the development of 3D carbon nanostructures that can provide unique capabilities for manufacturing carbon nanotube (CNT) electronic components, electrochemical probes, biosensors and tissue scaffolds. The shaped CNT arrays were grown on patterned catalytic substrate by chemical vapor deposition (CVD) method. The new fabrication process for catalyst patterning based on combination of nano-imprint lithography (NIL), magnetron sputtering and reactive etching techniques was proposed and studied. The optimal process parameters for each technique were evaluated. The catalyst was made by deposition of Fe and Co nanoparticles over alumina support layer on Si/SiO₂ substrate. The metal particles were …