Engineering Commons^™

Mechanical Reliability Of Porous Low-K Dielectrics For Advanced Interconnect: Study Of The Instability Mechanisms In Porous Low-K Dielectrics And Their Mediation Through Inert Plasma Induced Re-Polymerization Of The Backbone Structure, Yoonki Sa

Material Science and Engineering Dissertations - Archive

Continuous scaling down of critical dimensions in interconnect structures requires the use of ultralow dielectric constant (k) films as interlayer dielectrics to reduce resistance-capacitance delays. Porous carbon-doped silicon oxide (p-SiCOH) dielectrics have been the leading approach to produce these ultralow-k materials. However, embedding of porosity into dielectric layer necessarily decreases the mechanical reliability and increases its susceptibility to adsorption of potentially deleterious chemical species during device fabrication process. Among those, exposure of porous-SiCOH low-k (PLK) dielectrics to oxidizing plasma environment causes the increase in dielectric constant and their vulnerability to mechanical instability of PLKs due to the loss of methyl …

Nebraska Data Collection, Keyvan Zare Rami, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

Automated pavement performance data collection is a method that uses advanced technology to collect detailed road surface distress information at traffic speed. Agencies are driven to use automated survey techniques to enhance or replace their current manual distress survey because of the advantages of objective measurements, safety benefits, and reduced measurement time. As agencies move toward the transition to fully automated data collection methods, there are common concerns regarding how the output of the new method will match the current manual survey ratings and how they will be adopted into the existing Pavement Management System (PMS). This study evaluates the …

Development Of A Semicircular Bend (Scb) Test Method For Performance Testing Of Nebraska Asphalt Mixtures, Gabriel Nsengiyumva, Yong-Rak Kim, Taesun You

Nebraska Department of Transportation: Research Reports

No abstract provided.

Epitaxial Growth Of Si-Ge-Sn Alloys For Optoelectronic Device Application, Aboozar Mosleh

Graduate Theses and Dissertations

Microelectronics industry has experienced a tremendous change over the last few decades and has shown that Moore’s law has been followed by doubling the number of transistors on the chip every 18 months. However, continuous scaling down of the transistors size is reaching the physical limits and data transfer through metal interconnects will not be able to catch up with the increasing data processing speed in the future. Therefore, optical data transfer between chips and on-chip has been widely investigated. Silicon based optoelectronics has received phenomenal attention since Si has been the core material on which microelectronic industry has been …

Image Processing And Visualization Of Terahertz Pulsed Imaging Of Breast Cancer Tumors, Yuhao Wu

Graduate Theses and Dissertations

Terahertz imaging technology has grown substantially in recent years. With new advances made in the generation, manipulation, and detection of terahertz radiation, terahertz imaging has found its application as inspection tools in a wide range of areas including biomedicine, materials science, and aerospace industries. In the field of medical imaging, terahertz (THz) has emerged as a new imaging modality due to some fundamental physical properties of the THz wave. THz imaging has been used to examine various biological structures, and THz tomography has been developed to probe the 3D structures of those samples.

THz pulsed imaging (TPI) is one of …

Evaluation Of Conservation Practices Through Simulation Modeling And Tool Development, Gurdeep Singh

Graduate Theses and Dissertations

For the first objective, predicted impacts of selected Mississippi River Basin Initiative (MRBI) conservation practices (CPs) on sediment and nutrient loss were assessed. The study area was L’Anguille River Watershed (LRW), a priority focus watershed of the MRBI program and the simulated CPs were filter strip, critical area planting, grade stabilization structure, irrigation land leveling, irrigation pipeline, irrigation water management, and nutrient management. The Soil and Water Assessment Tool (SWAT) model was calibrated (1998 – 2005) and validated (2006 – 2012) for flow, sediment, total phosphorus (TP), and nitrate-nitrogen (NO3-N) at the Colt site (503 sq. km. drainage area) and …

A Platform For Fast Detection Of Let-7 Micro Rna Using Polyaniline Fluorescence And Image Analysis Techniques, Partha P. Sengupta

Master's Theses

The project describes a new strategy for transducing hybridization events through modulating intrinsic properties of the electroconductive polymer polyaniline (PANI). When DNA based probes electrostatically interact with PANI, its fluorescence properties are increased, a phenomenon that can be enhanced by UV irradiation. Hybridization of target nucleic acids results in dissociation of probes causing PANI fluorescence to return to basal levels. By monitoring restoration of base PANI fluorescence as little as 10^-11 M (10 pM) of target oligonucleotides could be detected within 15 minutes of hybridization. Detection of complementary oligos was specific, with introduction of a single mismatch failing to …

Prediction Of Rupture In Abdominal Aortic Aneurysm, Qusay Alfaori

Graduate Theses and Dissertations

Studying the development of abdominal aortic aneurysm (AAA) through quantification of its growth kinetics and rupture criteria is important to decrease the risk of this life-threatening event. Uniaxial and biaxial testing of healthy and time-dependent Type-I collagen degraded aortic specimens from pigs was performed. Stress-strain suitable mathematical models describing the behavior of abdominal aortic tissue were utilized to derive specific tissue properties and parameters. Reduction in Type-I collagen fraction was observed using picrosirius red staining method, bright field microscopy, and MATLAB. Finite Element Modeling (FEM) of healthy and time-dependent Type-I collagen degraded abdominal aortas were performed using ABAQUS finite element …

Designing Optical Properties In Infrared Glass, Benn Gleason

All Dissertations

Chalcogenide glasses (ChGs) are well-known for their attractive optical properties, such as high refractive index and transparency in across infrared wavelengths. ChGs also possess the ability to compositionally tune properties such as the refractive index, the thermo-optic coefficient, and other non-optical properties. Chalcogenide glasses with compositionally tailored physical and optical properties will provide optical designers with new materials necessary to create novel infrared imaging systems requiring new or expanded functionality. This dissertation has evaluated the relationship between glass composition, the resulting atomic structure, and resulting optical and thermo-optical properties, with specific focus on the infrared refractive index and the thermo-optic …

Effect Of Tig Welding Parameters On Strain-Age Cracking In Joining Nickel-Based Superalloy, Gtd-111 With Inconel 625, Athittaya Athiroj, Panyawat Wangyao

Journal of Metals, Materials and Minerals

Excellent mechanical properties at high temperature of nickel-based superalloys brought them to extensive application in severe operating conditions. However, the great mechanical properties deteriorate after long-term exposure to high temperature and it frequently causes failure of the component e.g. cracking. TIG welding is considered as an economical way to refurbish the minor damage component as replacement with new one is costly due to high material cost and complexity in manufacturing processes. Unfortunately, heat from welding that applies to the component may create new cracks during and after process from liquation and strain-age cracking. This phenomena is problem especially in precipitation-hardened …

Mechanical Properties Of Interpenetrating Phase Composites Using Open-Cell Al Foams With Natural Rubber And Polyethylene, Kunmutta Angamnuaysiri, Seksak Asavavisithchai

Journal of Metals, Materials and Minerals

Interpenetrating phase composites (IPCs) were produced by conventional casting process, in vacuum atmosphere, using open-cell Al foams as matrix, and filled with either natural rubber or polyethylene. Mechanical properties of IPCs strongly depends on types of polymeric phases. It is found that the IPCs with polyethylene show an increase in compressive strength as well as failure strain. However, a large decrease of compressive strength is observed in the IPCs with natural rubber, as a result of cracks along the interface between Al foam and the rubber. These cracks are distributed throughout foam structure in the IPCs.

Microstructure And X-Ray Diffraction Analysis Of Al-Cu Couples Diffused At High Temperature, Jaime Hinojosa-Torres, Juan Manuelaceves-Hernández, Andres Herrera-Vázquez, Victor Manuelcastaño-Meneses

Journal of Metals, Materials and Minerals

By employing a thermal field of 813 K, couples of Al with Cu were welded as consequence of the atomic diffusion. The periods of permanency inside the field were 200, 320 and 480 hours. After the periods of test, SEM observations show the formation of two contiguous plate likes (~15 to 30 micrometres, width) that they are in normal position to the concentration gradient. By utilizing elemental analyses and X-ray diffraction techniques one plate like was identified as the h2 phase (CuAl) and the other one as the q phase (CuAl2) of the aluminium-copper system. Immediate to the q plate …

Biomechanical Performances Of Networked Polyethylene Glycol Diacrylate: Effect Of Photoinitiator Concentration, Temperature, And Incubation Time, Morshed Khandaker, Albert Orock, Stefano Tarantini, Jeremiah White, Ozlem Yasar

Publications and Research

Nutrient conduit networks can be introduced within the Polyethylene Glycol Diacrylate (PEGDA) tissue construct to enable cells to survive in the scaffold. Nutrient conduit networks can be created on PEGDA by macrochannel to nanochannel fabrication techniques. Such networks can influence the mechanical and cell activities of PEGDA scaffold. There is no study conducted to evaluate the effect of nutrient conduit networks on the maximum tensile stress and cell activities of the tissue scaffold.The study aimed to explore the influence of the network architecture on the maximum tensile stress of PEGDA scaffold and compared with the nonnetworked PEGDA scaffold. Our study …

Spatial Variability Of Soil Velocity Using Passive Surface Wave Testing, Daniel Raymond Wagstaffe

Master's Theses

Lifelines such as highways, pipelines, telecommunication lines, and powerlines provide communities with vital services, and their functionality is dependent upon the foundation soil that supports them. However, when designing the infrastructure, it can be difficult to know where to test the soil in order to give spatially representative sampling, particularly for long, lifeline structures. Finding this distance requires knowledge of the spatial correlation and/or the spatial variability of the soil parameter (stiffness, cohesion, etc.). But this correlation distance is not typically found in practice because it requires large amounts of data and the costs of retrieving that data can be …

Contribution To T He Onboard Context Sensitive Information System ( Of Commercial Aircraft, Wei Tan

Theses and Dissertations

Pilots currently use paper-based documentation and electronic systems (e.g., Electronic Centralized Aircraft Monitor (ECAM) for Airbus, and Engine Indication and Crew Alerting System (EICAS) for Boeing) to help them perform procedures to ensure safety, efficiency and comfort on commercial aircrafts. Management of interconnections among paper-based operational documents can be a challenge for pilots, especially when time pressure is high in normal, abnormal, and emergency situations. This dissertation is a contribution to the design of an Onboard Context-Sensitive Information System (OCSIS). The claim is that the use of contextual information facilitates access to appropriate operational content at the right time either …

Predicted Stresses In A Ball-Grid-Array (Bga)/Column-Grid-Array (Cga) Assembly With A Low Modulus Solder At Its Ends, Ephraim Suhir, Reza Ghaffarian

Mechanical and Materials Engineering Faculty Publications and Presentations

A simple, easy-to-use and physically meaningful predictive model is suggested for the assessment of thermal stresses in a ball-grid-array or a column-grid-array with a low modulus solder material at the peripheral portions of the assembly. It is shown that the application of such a design can lead to a considerable relief in the interfacial stresses, even to an extent that inelastic strains in the solder joints could be avoided. If this happens, the fatigue strength of the bond and of the assembly as a whole will be improved dramatically: low-cycle fatigue conditions will be replaced by the elastic fatigue condition, …

Transforming C Openmp Programs For Verification In Civl, Michael Rogers

School of Computing: Dissertations, Theses, and Student Research

There are numerous way to express parallelism which can make it challenging for developers to verify these programs. Many tools only target a single dialect but the Concurrency Intermediate Verification Language (CIVL) targets MPI, Pthreads, and CUDA. CIVL provides a general concurrency model that can represent pro- grams in a variety of concurrency dialects. CIVL includes a front-end that support all of the dialects mentioned above. The back-end is a verifier that uses model checking and symbolic execution to check standard properties.

In this thesis, we have designed and implemented a transformer that will take C OpenMP programs and transform …

Using Software-Defined Networking To Improve Campus, Transport And Future Internet Architectures, Adrian Lara

School of Computing: Dissertations, Theses, and Student Research

Software-defined Networking (SDN) promises to redefine the future of networking. Indeed, SDN-based networks have unique capabilities such as centralized control, flow abstraction, dynamic updating of forwarding rules and software-based traffic analysis. SDN-based networks decouple the data plane from the control plane, migrating the latter to a software controller. By adding a software layer between network devices and applications, features such as network virtualization and automated management are simpler to achieve.

In this dissertation, we show how SDN-based deployments simplify network management at multiple scales such as campus and transport networks, as well as future Internet architectures. First, we propose OpenSec, …

Bandwidth Estimation For Virtual Networks, Ertong Zhang

School of Computing: Dissertations, Theses, and Student Research

Cloud computing is transforming a large part of IT industry, as evidenced by the increasing popularity of public cloud computingservices, such as Amazon Web Service, Google Cloud Platform, Microsoft Windows Azure, and Rackspace Public Cloud. Manycloud computing applications are bandwidth-intensive, and thus the network bandwidth information of clouds is important for theirusers to manage and troubleshoot the application performance.

The current bandwidth estimation methods originally developed for the traditional Internet, however, face great challenges in clouds dueto virtualization that is the main enabling technique of cloud computing. First, virtual machine scheduling, which is an importantcomponent of computer virtualization for processor …

Comments On “The Principal Axes Decomposition Of Spatial Stiffness Matrices”, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

A significant amount of research has been directed toward developing a more intuitive appreciation of spatial elastic behavior. Results of these analyses have been described in terms of behavior decompositions and in terms of behavior centers. In a recent paper entitled “The Principal Axes Decomposition of Spatial Stiffness Matrices” by Chen et al. (IEEE Trans. Robot., vol. 31, no. 1, pp. 191-207), a decomposition of spatial stiffness was presented, and centers of stiffness and compliance were identified. The results presented in the paper have substantial overlap with previously published results and redefine previously used terms. The objective of this communication …

Swat Model Simulation Of Bioenergy Crop Impacts On Water Quality In Cache River Watershed, Eeshan Kumar

Graduate Theses and Dissertations

Energy security through increased biofuel production is one of the components of the Energy Independence and Security Act (EISA) 2007. As per EISA 2007 mandate, appropriate independent research institutes are required to assess concerns to natural biodiversity due to biofuel production and report it to the Congress through the Environment Protection Agency (EPA). Planners, researchers, and agencies concerned with environmental regulations, ideally, would like to have location-specific information about the impacts for developing appropriate management interventions. This study examines long-term impacts on water quality in response to targeted (i.e. marginal lands) production of biofuel crops by setting up two SWAT …

Exploring Emerging Technologies For The Built Environment Circa 2015 For Use In Architectural Engineering And Related Majors, Connor J. Hanlon

Architectural Engineering

For this senior project I am seeking to combine my knowledge of Structural Engineering with Construction Management. For this task, I have decided to look at Building Information Modeling (BIM). In this project I investigate the BIM tools Trimble Tekla Structures and Autodesk Navis- works Manage. Tekla is a modeling, fabrication, and design program. Navisworks is a visualiza- tion and Clash Detection tool. For this project I have identiÅied two main goals relating to Navis- works and Tekla:

1. Create content to allow students and professors learn how to use Tekla and Navisworks

2. Determine the capabilities of these softwares, and Åigure …

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Tron 2.0 - The Experience, Alecsandro G. Vitale, Alexander W. Billings, Jordan Delfino, William Beechinor, Kelly Rorden

Architectural Engineering

The goal of this senior project was to come up with a structural-engineering-related schematic design for a roller coaster to be installed in Disneyland called TRON 2.0: The Experience. This involved looking at both design processes that we had already learned through our curriculum as well as researching concepts that were previously foreign to us, namely the dynamic application of loads and the effects of fatigue stresses.

A story was established based on the source material: the TRON movies produced by Walt Disney Studios. Thematic elements from the story were used as the basis for design implications that would become …

Ecohydrological Controls On Grass And Shrub Above-Ground Net Primary Productivity In A Seasonally Dry Climate, Anthony J. Parolari, Michael L. Goulden, Rafael L. Bras

Civil and Environmental Engineering Faculty Research and Publications

Seasonally dry, water‐limited regions are often co‐dominated by distinct herbaceous and woody plant communities with contrasting ecohydrological properties. We investigated the shape of the above‐ground net primary productivity (ANPP) response to annual precipitation (P_a) for adjacent grassland and shrubland ecosystems in Southern California, with the goal of understanding the role of these ecohydrological properties on ecosystem function. Our synthesis of observations and modelling demonstrates grassland and shrubland exhibit distinct ANPP‐P_a responses that correspond with characteristics of the long‐term P_a distribution and mean water balance fluxes. For annual grassland, no ANPP occurs below a ‘precipitation …

Hvdc Systems Fault Analysis Using Various Signal Processing Techniques, Benish Paily

Doctoral

The detection and fast clearance of faults are important for the safe and optimal operation of HVDC systems. In HVDC systems, various types of AC faults (rectifier & inverter side) and DC faults can occur. It is therefore necessary to detect the faults and classify them for better protection and diagnostics purposes. Various techniques for fault detection and classification in HVDC systems using signal processing techniques are presented and investigated in this research work. In this research work, it is shown that the wavelet transformation can effectively detect abrupt changes in system signals which are indicative of a fault. This …

Microcontroller Application For Linear And Rotational Motion Sensing, Zachary Mintzer

Computer Engineering

No abstract provided.

Cormant Cs-Edis, Steven Jarred Stelfox

Computer Science and Software Engineering

No abstract provided.

High Temperature Hepa Filter Test Unit Upgrades, Alexander Krippner, Ian Corcorran, Michael Burlando

Mechanical Engineering

No abstract provided.

High Speed Jet Turbine Test Final Report, Kenneth Enstrom, Cameron Naugle, Isaac Thomas, Cody Lee

Mechanical Engineering

At high flight altitudes and speeds, external airplane elements are subject to immense loads. External devices must be put through testing that simulates these loads to ensure safety of the device. Our system will subject a device in need of testing to a jet of air, similar to wind seen on the surface of an airplane. The High Speed Air Jet Turbine Test project team has been tasked to design, build, and test an apparatus capable of acquiring real world flight data for micro-ram air turbines (microRAT). The micro-RAT is a device that provides power to an electrical device by …

Could Application Of Column-Grid-Array (Cga) Technology Result In Inelastic-Strain-Free State-Of-Stress In Solder Material?, Ephraim Suhir, Reza Ghaffarian, Johann Nicolics

Mechanical and Materials Engineering Faculty Publications and Presentations

Physically meaningful and easy-to-use analytical stress model is developed for a short cylinder (beam) clamped at the ends and subjected to bending caused by the ends offset. The offset is due, in its turn, to an external lateral force that has to be determined from the known offset. It is envisioned that such a beam can adequately represent the state of stress in a column-grid-array (CGA) solder joint interconnection experiencing thermal loading due to the thermal expansion/contraction mismatch of the IC package and the printed circuit board (PCB). The CGA designs are characterized by considerably higher stand-off heights than ball-grid-array …