Engineering Commons^™

Self-Similar Random Process And Chaotic Behavior In Serrated Flow Of High Entropy Alloys, Shuying Chen, Liping Yu, Jingli Ren, Xie Xie, Xueping Li, Ying Xu, Guangfeng Zhao, Peizhen Li, Fuqian Yang, Yang Ren, Peter K. Liaw

Chemical and Materials Engineering Faculty Publications

The statistical and dynamic analyses of the serrated-flow behavior in the nanoindentation of a high-entropy alloy, Al_0.5CoCrCuFeNi, at various holding times and temperatures, are performed to reveal the hidden order associated with the seemingly-irregular intermittent flow. Two distinct types of dynamics are identified in the high-entropy alloy, which are based on the chaotic time-series, approximate entropy, fractal dimension, and Hurst exponent. The dynamic plastic behavior at both room temperature and 200 °C exhibits a positive Lyapunov exponent, suggesting that the underlying dynamics is chaotic. The fractal dimension of the indentation depth increases with the increase of temperature, and …

Financial Modelling And Analysis Of The Management Of Dredged Marine Sediments – Development Of A Decision Support Tool, Joseph R. Harrington, J. Murphy, M. Coleman, D. Jordan, G. Szacsuri

Publications

Objective

The management of dredged sediments is a major challenge for many ports and harbours who need to maintain navigable access. Sediment volumes produced may be significant and expensive to manage. This paper presents financial modelling and analysis for the management of dredged marine sediment using a financial model developed which has the potential to be used as decision support tool by stakeholders in the Sector including Ports, Engineering Consultancies and Regulators.

Data/Methodology

A decision support tool has been developed to assess the financial aspect of a range of management uses for dredged marine sediments for a range of different …

Γ/Γ' Co-Base Superalloys – New High Temperature Materials Beyond Ni-Base Superalloys?, Steffen Neumeier, Christopher H. Zenk, Lisa P. Freund, Mathias Göken

Beyond Nickel-Based Superalloys II

In 2006 a new L1₂ phase, Co₃(Al,W), was discovered in the Co-Al-W system which has led to the development of novel Co-base superalloys with g/g¢ microstructures similar to those of the well-established Ni-base superalloys. First investigations on simple ternary alloys could show that these Co-Al-W based alloys exhibit higher solidus temperatures and show less segregations after casting compared to typical Ni-base superalloys. This leads to the question whether this g/g¢ Co-base superalloys can be regarded as new class of high temperature materials that can compete with or even supersede established Ni-base superalloys.

In the first part of …

Microstructural Analysis And High Temperature Creep Of Mo-9si-8b Alloys With Al And Ge Additions, Peter Kellner, Rainer Völkl, Uwe Glatzel

Beyond Nickel-Based Superalloys II

Refractory metals and their alloys show potential for high temperature applications, due to the increased melting point and creep resistance. Spark plasma sintering technology as well as argon arc melting is used to prepare quaternary and quinternary Mo-9Si-8B-xAl-yGe (x is 0 or 2; y is 0 or 2) samples. Compositions are stated in at.%. All the compositions consist of a Mo solid solution (α-Mo) and two intermetallic phases: Mo₃Si (A15) and Mo₅SiB₂ (T₂). On the one hand, no zirconium is added to the alloys to avoid evaporation of MoO₃ due to the …

Enhanced Oxidation Resistance Of Ti-Rich Mo-Si-B Alloys By Pack-Cementation Process, Camelia Gombola, Daniel Schliephake, Martin Heilmaier, John H. Perepezko

Beyond Nickel-Based Superalloys II

To increase efficiency by higher combustion temperatures of aircraft engines and energy generation, new high temperature materials are inevitable. Mo-Si-B alloys for example satisfy several requirements such as good oxidation and creep resistance. Recently, novel Ti-rich Mo-Si-B alloys have shown an increased creep resistance compared to Ti-free Mo-Si-B alloys by the formation of Ti-silicide precipitates during processing. However, due to the formation of a duplex SiO₂ – TiO₂ oxide layer, where fast inwards diffusion of oxygen takes place, the oxidation resistance is poor.

In this study we show that oxidation resistance of Mo-Si-B-Ti alloys can be enhanced drastically …

Control Of Networked Systems With Engineering Applications, Housheng Su, Michael Z.Q. Chen, Qing Hui, Yuan Fan, Zhiwei Gao

Department of Electrical and Computer Engineering: Faculty Publications

Recently, control of networked systems problems has attracted much attention among researchers in biology, physics, control engineering, and computer science for decades, partially due to the broad applications of control of networked systems in many engineering areas including cooperative control of mobile robots and estimation of mobile sensor networks. The study of complex network topology and modeling is to understand the influence of network structure on its function and consequently to find effective ways to improve network performance.

This special issue focuses on theoretical and technological achievements in control of networked systems. The contents of the accepted papers are summarized …

Microstructural Stability Of Co-Re-Cr-Ta-C Alloy Strengthened By Tac Precipitates, Debashis Mukherji, Ralph Gilles, Lukas Karge, Pavel Strunz, Přemysl Beran, Joachim Rösler

Beyond Nickel-Based Superalloys II

It is becoming increasingly clear that new materials that can operate at substantially higher temperatures than Ni-base superalloys are needed for future gas turbines. High melting Co-Re-Cr based alloy strengthened by carbides, particularly the MC type carbide, shows promise [1]. A fine dispersion of globular TaC precipitate is exploited for this purpose. Additionally Cr, which is mainly added to improve oxidation resistance, also stabilizes lamellar M₂₃C₆ type Cr carbide. The microstructure of a Co-Re-Cr-Ta-C alloy with the two types of carbides is seen in Fig. 1.

Please click Additional Files below to see the full abstract.

1916 - Irrigation Districts In California, 1887-1915, Bulletin No. 2

Miscellaneous Documents and Reports

The 1916 report covers the establishment of irrigation districts between 1887 and 1915. Under the Wright Act of 1887, the State sought to conferred on farming communities powers of municipalities in the purchase or construction and operation of irrigation works. The report considered the old irrigation districts from the point of view of what seemed to have been their purpose. They were grouped as follows:

Districts essentially nonspeculative and· formed to meet a bona fide demand for new irrigation works: Orland, Kraft, Orland Southside, Central, Colusa, Browns Valley, Modesto, Turloek, Huron, Tipton, Tule · River, Kern and Tulare, Poso, Ama'rgeza, …

The Confounding Effects Of Particle Size And Substrate Bulk Density On Phanerochaete Chrysosporium Pretreatment On Panicum Virgatum, Amanda N. Hickman, Sue E. Nokes, William S. Sympson, Mathew J. Ruwaya, Michael D. Montross, Barbara L. Knutson

Biosystems and Agricultural Engineering Faculty Publications

Phanerochaete chrysosporium treatment is less effective as a biological pretreatment on feedstock with larger particle sizes. We hypothesized that the improved effectiveness of the pretreatment when smaller particle sizes are used may be due to the inherently higher bulk density with smaller particle sizes. The effects of substrate bulk density and particle size on the efficacy of P. chrysosporium pretreatment of switchgrass (Panicum virgatum) was tested experimentally. Phanerochaete chrysosporium was grown on senesced switchgrass (2 different particle sizes) with various bulk densities. In all treatments, the fungal-pretreated samples released more glucose during enzymatic saccharification than the control sample. …

Enhancing Mobile Cloud Computing Security Using Steganography, Hassan Reza, Madhuri Sonawane

Computer Science Faculty Publications

Cloud computing is an emerging and popular method of accessing shared and dynamically configurable resources via the computer network on demand. Cloud computing is excessively used by mobile applications to offload data over the network to the cloud. There are some security and privacy concerns using both mobile devices to offload data to the facilities provided by the cloud providers. One of the critical threats facing cloud users is the unauthorized access by the insiders (cloud administrators) or the justification of location where the cloud providers operating. Although, there exist variety of security mechanisms to prevent unauthorized access by unauthorized …

Increasing Collegiate Flight Training Fleet Utilization Through The Use Of An Aircraft Assignment Algorithm, John H. Mott, Daniel Henao, Mitchell S. Hodgen, Darcy M. Bullock

International Journal of Aviation, Aeronautics, and Aerospace

The operational efficiency of fleet aircraft employed for student flight training in collegiate aviation programs is strongly influenced by scheduling, among other factors. The average utilization rate for the fleet operated by the Purdue University School of Aviation and Transportation Systems was found to be 24% (Avery, 2014), and there is no data to suggest that that this rate is atypical in similar institutional programs. Mott and Bullock (2015) identified several means by which the utilization rate could be increased, and improvements in the dispatch and scheduling process were a key component of those recommendations. This article describes a scheduling …

Mo-9si-8b Alloys With Additons Of Zr – Microstructure And Creep Properties, Uwe Glatzel, Christian Hochmuth, Rainer Völkl

Beyond Nickel-Based Superalloys II

Three phase Mo-9Si-8B (at.%) alloys are a prominent example for a potential new high temperature structural material. Due to their high melting point and excellent creep resistance. In this study the effect of Zr addition (0…4 at.%) on the microstructure and creep properties of Mo-9Si-8B (at.%) alloys is investigated. Two powder metallurgical processes, hot isostatic pressing (HIP) and spark plasma sintering (SPS), are used to prepare specimens. The resulting microstructures are examined using SEM and TEM analysis. SPS alloys exhibit smaller grain sizes and fewer oxides compared to the HIP alloys, because of the oxygen availability during HIP. The more …

Suppressing Restricted Shock Separation In A Subscale Rocket Nozzle Using Contour Geometry, K. Schomberg, J. Olsen, A. J. Neely, Graham Doig

Aerospace Engineering

The use of a thrust-optimized contour (TOC) for the supersonic nozzle in a rocket engine will inherently maximize the propulsive efficiency and payload capacity of the entire launch system. A TOC can be approximated using a skewed parabola, commonly referred to as a thrust-optimized parabola (TOP), and the TOP contour can be manipulated to avoid undesirable flow separation during low-altitude operation by increasing the static wall pressure at the expense of thrust (approximately 0.1 0.2%). For this reason, a TOP design is often used in nozzles with a high area ratio, such as those used in the Vulcain and Vulcain …

Microstructure And Creep Resistance Of Ti-Rich Mo + Mo5si3 + Mo5sib2 Alloys, Daniel Schliephake, Martin Heilmaier

Beyond Nickel-Based Superalloys II

New materials are necessary to increase efficiency of power generation and aircraft engines by higher combustion temperatures. Recently, it was found that alloying with high amounts of Ti replaces Mo₃Si by Mo₅Si₃ and stabilizes the phase field Mo + Mo₅Si₃ + Mo₅SiB₂, which could be beneficial for higher oxidation resistance, since Mo₅Si₃ is more oxidation resistant than Mo₃Si. Additional, Ti-rich Mo-Si-B alloys show an increased creep resistance compared to Ti-free Mo-Si-B alloys and a significant reduction in the alloy density. However, using the …

Effects Of Emf Emissions From Undersea Electric Cables On Coral Reef Fishes, Robert F. Jermain

HCNSO Student Theses and Dissertations

The objective of this project was to determine if the electromagnetic field (EMF) emissions from undersea power cables impacted the local and transient marine life, with an emphasis on reef fishes. The work was done at South Florida Ocean Measurement Facility of Naval Surface Warfare Center, Carderock Division, Broward County, Florida. This facility functions as the hub for a range of active undersea detection and data transmission cables. It has multiple active submarine power cables that extend several miles offshore and which can deliver power and enable data transmission to and from a range of acoustic and EMF sensors. The …

Optimization Of Takeoffs On Unbalanced Fields Using Takeoff Performance Tool, Nihad E. Daidzic

International Journal of Aviation, Aeronautics, and Aerospace

Unbalanced field length exists when ASDA and TODA are not equal. Airport authority may add less expensive substitutes to runway full-strength pavement in the form of stopways and/or clearways to basic TORA to increase operational takeoff weights. Here developed Takeoff Performance Tool is a physics-based total-energy model used to simulate FAR/CS 25 regulated airplane takeoffs. Any aircraft, runway, and environmental conditions can be simulated, while complying with the applicable regulations and maximizing performance takeoff weights. The mathematical model was translated into Matlab, Fortran 95/2003/2008, Basic, and MS Excel computer codes. All existing FAR/CS 25 takeoff regulations are implemented. Average forces …

Design Of Gamma-Prime-Strengthened Co-Based Superalloys: Where We Are And Where We Need To Go, Eric A. Lass

Beyond Nickel-Based Superalloys II

Since the first report of a stable two-phase g-g’ (FCC-L12) phase field in ternary Co-Al-W in 2006, there has been significant research effort in developing this new class of Co-based g’-strengthened superalloys for high temperature applications. Much of the focus has been on characterizing and improving high temperature properties such as the g’ solvus temperature, high temperature strength and creep resistance, corrosion and oxidation behavior. Much of this work has been conducted experimentally utilizing the wealth of knowledge of Ni-based superalloys gathered over the last several decades. Efforts into developing effective modeling tools, such as thermodynamic and diffusion databases, have …

Dango (Doings And Goings On) - Vol. 22 | Issue 9, Rusty Towell, Matthew Kimball, Haley Stien, Cecily Towell, Aric Tate, Vicente Rojas, Caleb Hicks, Zhaojia Xi, Joshua Daniel Martinez, Paul Carstens, Reuben Byrd, Mike Daugherity, Donald Isenhower

DANGO: Doings and Goings On: Summer Research Newsletter, Department of Engineering and Physics

ACU Department of Engineering and Physics Weekly Summer Research Newsletter

Improving The Oxidation Resistance Of Refractory Metals Via Aluminum Diffusion Coatings And Halogen Effect, A.S. Ulrich, M.C. Galetz

Beyond Nickel-Based Superalloys II

Recently, refractory metals and their alloys have received increasing attention for the purpose of substituting Ni-based single crystal superalloys. Compared to commonly used materials, refractory metals have significantly higher melting points while their mechanical properties seem adequate at high temperatures. The main challenge for their application is, that refractory metals show low oxidation resistances at elevated temperatures. Aluminum diffusion layers are promising coatings to suppress harmful oxidation by forming a protective oxide layer. This study deals with the application of such aluminum reservoir layers and with the investigation of their protective properties. Four different unalloyed refractory metals, molybdenum, tantalum, tungsten …

58th Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 58th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Breckenridge, Colorado, July 17-21, 2016.

Conference Program, Howard J. Stone

Beyond Nickel-Based Superalloys II

No abstract provided.

Comprehensive Framework For Speed-Zone Guidelines, K Joseph Shrestha, Pramen Shrestha

Civil and Environmental Engineering and Construction Faculty Research

Speeding is often considered as one of the major reasons of traffic crashes. As a result, State Departments of Transportations (DOTs) receive requests from communities to decrease speed limits in towns along rural highways. Such requests, coupled with the lack of proper manuals, have forced state DOTs to reduce the speed limits. A proper speed-zone manual is required to establish consistent speed zones across a state. This paper reviewed the literature on speed, crashes, enforcement techniques, and speed-zone manuals. A nationwide survey was conducted to identify various factors affecting the decisions of speed zones establishing. This paper identified best practices …

Process Evaluation And Assessment Of Use Of A Large Scale Water Filter And Cookstove Program In Rwanda, Christina K. Barstow, Corey Nagel, Thomas Clasen, Evan A. Thomas

OHSU-PSU School of Public Health Faculty Publications and Presentations

Background: In an effort to reduce the disease burden in rural Rwanda, decrease poverty associated with expenditures for fuel, and minimize the environmental impact on forests and greenhouse gases from inefficient combustion of biomass, the Rwanda Ministry of Health (MOH) partnered with DelAgua Health (DelAgua), a private social enterprise, to distribute and promote the use of improved cookstoves and advanced water filters to the poorest quarter of households (Ubudehe 1 and 2) nationally, beginning in Western Province under a program branded Tubeho Neza (“Live Well”). The project is privately financed and earns revenue from carbon credits under the United Nations …

Suitability Testing For Possum Scientist-Astronaut Candidates Using The Suborbital Space Flight Simulator With An Iva Spacesuit, Pedro J. Llanos, Erik Seedhouse, Ryan L. Kobrick

Publications

This paper evaluates key functional data parameters that must be considered for suborbital spaceflight participants wearing pressurized suits for intravehicular activity (IVA). Data parameters of an analog spacesuit worn in an analog flight environment were obtained from 40 civilian participants using the Suborbital Space Flight Simulator (SSFS) at Embry-Riddle Aeronautical University (ERAU) while donning Final Frontier Design’s (FFD) fully pressurized third-generation spacesuit as part of their training for Project PoSSUM (the Polar Suborbital Science in the Upper Mesosphere Project). The physiological data collected included: blood pressure, electrocardiograms, heart rate, grip strength, and skin temperature. These parameters were measured using a …

Loss Model For Gallium Nitride Dc-Dc Buck Converter, Rushi Patel, Daniel Costinett

BCoE Publications

In recent years, more research has been done on Enhancement Mode Gallium Nitride (eGaN) converters as the world is moving towards more power efficient converters. The process to make converters more efficient was complicated and slow in the twentieth century. With help of simulation tools such as MATLAB and LTspice, this process has become much faster and reliable in the modern era. In order to make this process even faster, one of the important aspects in power electronics is to evaluate different losses in the converter. A model for estimating power losses for eGaN DC-DC buck converter (12V/1.2V) is illustrated …

Seismic Behavior And Design Of The Linked Column Steel Frame System For Rapid Return To Occupancy, Arlindo Pires Lopes

Dissertations and Theses

The Linked Column Frame (LCF) is a new brace-free lateral structural steel system intended for rapid return to occupancy performance level. LCF is more resilient under a design level earthquake than the conventional approaches. The structural system consists of moment frames for gravity that combines with closely spaced dual columns (LC) interconnected with bolted links for the lateral system. The LC links are sacrificial and intended to be replaced following a design level earthquake. The centerpiece of this work was a unique full-scale experiment using hybrid simulation testing; a combination of physical test of a critical sub-system tied to a …

Comparison Of Sfm Computer Vision Point Clouds Of A Landslide Derived From Multiple Small Uav Platforms And Sensors To A Tls Based Model, Samantha Ruggles, Joseph Clark, Kevin W. Franke, Derek Wolfe, Brandon Reimschiissel, Ronald Abraham Martin, Trent Okeson, John Hedengren

Faculty Publications

Structure from motion (SfM) computer vision is a remote sensing method that is gaining popularity due to its simplicity and ability to accurately characterize site geometry in three dimensions (3D). While many researchers have demonstrated the potential for SfM to be used with unmanned aerial vehicles (UAVs) to model in three dimensions various geologic features such as landslides, little is understood how the selection of the UAV platform can affect the resolution and accuracy of the model. This study evaluates the resolution and accuracy of 3D point cloud models of a large landslide that occurred in 2013 near Page, Arizona …

Film Performance Of Poly(Lactic Acid) Blends For Packaging Applications, Carlos A. Diaz, Hsunpao Y. Pao, Sungyoung Kim

Journal of Applied Packaging Research

Poly(lactic acid) (PLA), a biodegradable thermoplastic derived from renewable resources, stands out as a substitute to petroleum-based plastics. PLA based films for food packaging has been an area of both commercial and research interest within the context of sustainability. In spite of its high strength, packaging applications have been limited because PLA is more brittle than traditional oil-based plastics. Because of this, films display low tear and impact resistance and produce a loud crackling sound when manipulated. Although many studies address the toughening of PLA in the bulk, little attention has been placed on the film performance. The present study …

From Dilute Polyelectrolyte Solutions To Entangled Polyelectrolyte Networks: A Study Of Sodium Carboxymethyl Cellulose In Water By Light Scattering And Rheology, Juliette S. Behra, Timothy N. Hunter, Olivier J. Cayre, Johan Mattsson

Colloidal, Macromolecular & Biological Gels: Formulation, Properties & Applications

Sodium carboxymethyl cellulose (Na CMC) is widely used in industry for its thickening and swelling properties. Applications are very broad and include pharmaceutical, food, home and personal care products as well as the paper industry, water treatment and mineral processing. Na CMC is a linear negatively charged water-soluble polymer derived from cellulose. Its behaviour in water is known to be very complex and a function of several parameters including the characteristics of the polymer itself [1] such as molecular weight and degree of substitution as well as the solution concentration and dissolution conditions [2] (e.g. addition order of the system …

Large-Scale Optimization Of Synchronous Reluctance Machines Using Ce-Fea And Differential Evolution, Yi Wang, Dan M. Ionel, Vandana Rallabandi, Minjie Jiang, Steven Stretz

Power and Energy Institute of Kentucky Faculty Publications

A novel automated design optimization procedure based on the application of an ultrafast computationally efficient finite-element analysis (CE-FEA) for current-regulated synchronous reluctance machines supplied from power electronic converters is proposed. The CE-FEA uses only a minimum number of magnetostatic solutions in order to comprehensively evaluate performance, including ripple torque and core losses. The optimization algorithm is based on differential evolution, and uses as independent variables the torque angle and ratios for a generic rotor topology with four flux barriers. Two problems, one with two and the other with three objectives, are studied and results are compared. Global performance indices and …