Engineering Commons^™

Algebra Of Tankers, Margaret M. Romero

Theses and Dissertations

The Air Force's aerial refueling tanker aircraft provide essential support for deployment and employment of combat and combat support aircraft, by extending their endurance and enhancing fighting efficiency. As the lead command for air refuelers, Air Mobility Command (AMC) must frequently examine the capability of current and proposed tanker fleets to meet mission requirements due to limited tanker resources. Analysts in AMC primarily use the Combined Mating and Ranging Plans System to provide actual tanker/receiver aircraft schedules and flight plans that take into account numerous system constraints. However, this tool can take weeks to run. Even recently developed quick look …

Improving Intercontinental Ballistic Missile Maintenance Scheduling Through The Use Of Location Analysis Methodologies, Dale L. Overholts Ii

Theses and Dissertations

The events of September 11, 2001 have led to increased security requirements for all ICBM-related activities. Missile maintenance managers must explore new scheduling techniques to sustain weapon system readiness levels in light of published security enhancements. The problem of improving missile maintenance scheduling is modeled as a two-stage heuristic that utilizes the maximal covering location problem methodology. Maintenance activities are categorized and weighted according to published priority designation and mission impact. The model’s first stage seeks to select two security umbrellas that maximize the weighted sum of maintenance activities. Stage two seeks to determine a maintenance schedule comprised of launch …

Formation Flight Control For Aerial Refueling, Steven M. Ross

Theses and Dissertations

A controller is designed for an aircraft to autonomously fly formation during aerial refueling. Requirements for a refueling autopilot are stated. A six-degree-of-freedom model is developed for an F-16 lead aircraft and a Learjet LJ-25 wing aircraft. Bare airframe stability of both aircraft is investigated, and stability augmentation is performed. A Matlab Simulink® simulation is built to reproduce the sensor inputs that will be available to the wing aircraft in flight, including disturbances. Control frames are investigated to determine the optimum presentation of the error vector for control during the task of air refueling. Control laws are developed from the …

Creep-Rupture And Fatigue Behaviors Of Notched Oxide/Oxide Ceramic Matrix Composite At Elevated Temperature, Mark A. Sullivan

Theses and Dissertations

Oxide/oxide composites are being considered for use in high temperature aerospace applications where their inherent resistance to oxidation provides for better long life properties at high temperature than most other ceramic matrix composites (CMCs). One promising oxide/oxide CMC is Nextel 720/A (N720/A) which uses an 8-harness satin weave (8HSW) of Nextel 720 fibers embedded in a porous alumina matrix. Possible aerospace applications for N720/A will likely require inserting holes into the material for mounting and cooling purposes. The notch characteristics must be understood to ensure designs using the material are sufficient for the desired application. This research effort examined the …

Selective Advance Reservations Based On Host Movement Detection And Resource-Aware Handoff, Kyounghee Lee, Myungchul Kim, Chansu Yu, Ben Lee, Seungphil Hong

Electrical and Computer Engineering Faculty Publications

This paper proposes a new mechanism, which addresses the excessive advance reservation requirements of QoS guarantee methods for mobile Internet. To save resources for excessive advance reservations, the proposed mechanism employs a movement detection scheme for a mobile host (MH) using link-layer functionalities. With the movement detection scheme, advance reservations can be established at only where a MH is likely to visit soon. Another novel feature of our mechanism is resource-aware handoff direction scheme that allows a MH to choose its next BS according to not only the link-layer signal strength, but also the available amount of …

Splash: Systematic Proteomics Laboratory Analysis And Storage Hub, Siaw Ling Lo, You Tao, Qingsong Lin, Shashikant B. Joshi, Maxey Chung, Choy Leong Hew

Research Collection School Of Computing and Information Systems

In the field of proteomics, the increasing difficulty to unify the data format, due to the different platforms/instrumentation and laboratory documentation systems, greatly hinders experimental data verification, exchange, and comparison. Therefore, it is essential to establish standard formats for every necessary aspect of proteomics data. One of the recently published data models is the proteomics experiment data repository [Taylor, C. F., Paton, N. W., Garwood, K. L., Kirby, P. D. et al., Nat. Biotechnol. 2003, 21, 247-254]. Compliant with this format, we developed the systematic proteomics laboratory analysis and storage hub (SPLASH) database system as an informatics infrastructure to support …

Threading And Autodocumenting News Videos: A Promising Solution To Rapidly Browse News Topics, Xiao Wu, Chong-Wah Ngo, Qing Li

Research Collection School Of Computing and Information Systems

This paper describes the techniques in threading and autodocumenting news stories according to topic themes. Initially, we perform story clustering by exploiting the duality between stories and textual-visual concepts through a co-clustering algorithm. The dependency among stories of a topic is tracked by exploring the textual-visual novelty and redundancy of stories. A novel topic structure that chains the dependencies of stories is then presented to facilitate the fast navigation of the news topic. By pruning the peripheral and redundant news stories in the topic structure, a main thread is extracted for autodocumentary

Influence Of Pulmonary Arterial Endothelial Cells On Quinone Redox Status: Effect Of Hyperoxia-Induced Nad(P)H:Quinone Oxidoreductase 1, Marilyn P. Merker, Said H. Audi, Robert D. Bongard, Brian J. Lindemer, Gary S. Krenz

Biomedical Engineering Faculty Research and Publications

The objective of this study was to examine the impact of chronic hyperoxic exposure (95% O₂ for 48 h) on intact bovine pulmonary arterial endothelial cell redox metabolism of 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ). DQ or durohydroquinone (DQH₂) was added to normoxic or hyperoxia-exposed cells in air-saturated medium, and the medium DQ concentrations were measured over 30 min. DQ disappeared from the medium when DQ was added and appeared in the medium when DQH₂ was added, such that after ∼15 min, a steady-state DQ concentration was approached that was ∼4.5 times lower for the hyperoxia-exposed than the normoxic …

Beneath The Tip Of The Iceberg: A Human Factors Analysis Of General Aviation Accidents In Alaska Versus The Rest Of The United States, Cristy Detwiler, Carla Hackworth, Kali Holcomb, Albert Boquet, Elaine Pfleiderer, Douglas Wiegmann, Scott Shappell

Publications

Historically, general aviation (GA) accidents have been overlooked and their impact under-appreciated when compared with those in the commercial or military sector. Recently however, the Federal Aviation Administration and other governmental and civilian organizations have focused their attention on one piece of this proverbial “iceberg,” that being GA accidents occurring in Alaska. This study examines more than 17,000 GA accidents using the Human Factors Analysis and Classification System. Comparisons of Alaska to the rest of the U.S. (RoUS) included traditional demographic and environmental variables, as well as the human errors committed by aircrews. Overall, categorical differences among unsafe acts (decision …

On Innovative Methods Of Induction Motor Interturn And Broken-Bar Fault Diagnostics, Behrooz Mirafzal, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

A fault indicator, the so-called swing angle, for broken-bar and interturn faults is investigated in this paper. This fault indicator is based on the rotating magnetic-field pendulous-oscillation concept in faulty squirrel-cage induction motors. Using the "swing-angle indicator," it will be demonstrated here that an interturn fault can be detected even in the presence of machine manufacturing imperfections. Meanwhile, a broken-bar fault can be detected under both direct-line and PWM excitations, even under the more difficult condition of partial-load levels. These two conditions of partial load and motor manufacturing imperfections, which are considered as difficult situations for fault detection, are investigated …

Integrated Antenna For Multiband Multi-National Wireless Combined With Gsm1800/Pcs1900/Imt2000 + Extension, Matthias John, Max Ammann

Articles

A printed triple-band monopole antenna appropriate for use as a terminal antenna in modern wireless multiband systems is proposed. The impedance bandwidth of each band has been optimised using a quasi-Newton technique and the bandwidth includes virtually all wireless bands. Various parameter sweeps are presented which improve our understanding of the antenna, in particular, the effect of groundplane-size and branch-off point on impedance bandwidth and radiation pattern.

Ischemia Reperfusion Dysfunction Changes Model-Estimated Kinetics Of Myofilament Interaction Due To Inotropic Drugs In Isolated Hearts, Samhita S. Rhodes, Amadou Ks Camara, Kristina M. Ropella, Said H. Audi, Matthias L. Riess, Paul S. Pagel, David F. Stowe

Biomedical Engineering Faculty Research and Publications

Background

The phase-space relationship between simultaneously measured myoplasmic [Ca²⁺] and isovolumetric left ventricular pressure (LVP) in guinea pig intact hearts is altered by ischemic and inotropic interventions. Our objective was to mathematically model this phase-space relationship between [Ca²⁺] and LVP with a focus on the changes in cross-bridge kinetics and myofilament Ca²⁺ sensitivity responsible for alterations in Ca²⁺-contraction coupling due to inotropic drugs in the presence and absence of ischemia reperfusion (IR) injury.

Methods

We used a four state computational model to predict LVP using experimentally measured, averaged myoplasmic [Ca²⁺] transients …

Learning Real-Time A* Path Planner For Unmanned Air Vehicle Target Sensing, Jason K. Howlett, Timothy W. Mclain, Michael A. Goodrich

Faculty Publications

This paper presents a path planner for sensing closely-spaced targets from a fixed-wing unmanned air vehicle (UAV) having a specified sensor footprint. The planner is based on the learning real-time A* (LRTA*) search algorithm and produces dynamically feasible paths that accomplish the sensing objectives in the shortest possible distance. A tree of candidate paths that span the area of interest is created by assembling primitive turn and straight sections of a specified step size in a sequential fashion from the starting position of the UAV. An LRTA* search of the tree produces feasible paths any time during its execution and …

Piezoresistive Feedback For Decreased Response Time Of Mems Thermal Actuators, Robert K. Messenger, Timothy W. Mclain, Larry L. Howell

Faculty Publications

Feedback control is commonly used in positioning systems to improve dynamic response, disturbance rejection, accuracy, and repeatability. Similar benefits can be expected for microelectromechanical systems (MEMS) that are used for positioning applications. Sensing at the micro level poses significant challenges. Most of these challenges are associated with the small size of the devices and the small motions and forces which are of interest. In many situations, applying the macro system paradigm, where the sensor is a component that is added to the system, leads to unacceptable results. At the macro level, sensors are typically small relative to the systems they …

Electroless Nickel Plating On Carbon Nanotube With Non-Palladium Activation Procedure, Guang-Hui Hu, Hui-Huang Wu, Fang-Zu Yang

Journal of Electrochemistry

A new procedure of surface activation without using palladium salt was proposed for electroless nickel plating on carbon nanotubes.In the procedure,carbon nanotubes were oxidized by nitric acid and then neutralized with NaOH to create carboxyl surface groups which were used to adsorb Ni²⁺ ions,thereafter the adsorbed Ni²⁺ ions were chemically reduced into Ni nano-particles as a catalytic center for electroless nickel deposition,all these were further confirmed by infrared absorption spectra and electron microscopic observations.The results indicate that the procedure is feasible to electroless nickel plating on carbon nanotubes.The different morphology of deposits obtained from electroless plating was also …

Conductivity Of Comb Polyether Pure Solid Polymer Electrolyte, Lin Ye, Peng Gao, Zeng-Guo Feng, Feng Wu, Shi Chen, Guo-Qing Wang

Journal of Electrochemistry

A comb polymer was synthesized through cationic ring-opening polymerization starting from a monomer 3-hydroxymethyl-3-methyl-oxetane.The ion conductivity was measured by CHI660A electrochemical station under various lithium salt concentrations and various temperatures.The highest ion conductivity was recorded to be 10^-4.43 S/cm at room temperature and 10^-3.44 S/cm at 80 ℃.DSC results showed that the segment moves more difficultly with the increasing of lithium salts concentration.XPS found the existence of aggregating lithium ions in POE5 and POE10,and it suggested that POE20 had a suitable lithium concentration for polymer electrolyte.

Studies On Pva-Cmc-Koh-H2O Alkaline Polymer Electrolytes, An-Bao Yuan, Jun Zhao

Journal of Electrochemistry

A given amount of sodium carboxymethyl cellulose(CMC)was added to PVA complex and thus the PVA-CMC-KOH-H₂O alkaline polymer electrolyte with this modification was prepared.The properties of the polymer electrolyte films were characterized by AC impedance,cyclic voltammetry,differential thermal analysis and infrared spectroscopic analysis methods.The polymer electrolyte exhibited a high ionic conductivity,typically 10^-2S·cm^-1 with an electrochemical stability window of about 1.6 V on stainless steel blocking electrodes.The influence of the film composition such as KOH,H₂O and CMC on ion conductivity was investigated.In addition,a preliminary study was carried out on the polymer electrolyte for Ni/MH battery.It was …

Anodic Behaviors Of Pb-Ca-Sn-Re Alloy And Tradditional Pb-Ca-Sn Alloy In Sulfuric Acid Solutions, Dang-Guo Li, Gen-Shu Zhou, Liang Yao, Guan-Fa Lin, Mao-Sheng Zheng

Journal of Electrochemistry

The anodic behaviors of Pb-Ca-Sn-Re and Pb-Ca-Sn alloys were investigated at 1.28 V(vsHg/(H₂SO₄)) in 4.5 mol/L sulfuric acid solution by means of ac voltammetry,ac impedance and cyclic voltammetry.The results showed that the corrosion-resistance property of Pb-Ca-Sn-Re alloy is better than that of tradditional Pb-Ca-Sn alloy,the growth of Pb(Ⅱ) compounds was inhibited in the film of Pb-Ca-Sn-Re alloy,and the film impedance of Pb-Ca-Sn-Re alloy was decreased,indicating that the conductivity of the film was(increased),which is helpful to enhance the deep recycling property for lead acid battery.

Mechanism Of Self Discharge Performance Improvement In The Ni-Mh Batteries With Naoh Electrolyte, Xiao-Feng Li, Tong-Chi Xia, Hui-Chao Dong, Yan-Wei Wei

Journal of Electrochemistry

The self-discharge performance and charge efficiency at 60 ℃ for Ni-MH battery can be markedly enhanced by using NaOH electrolyte instead of KOH electrolyte.Both the results of electrochemical impedance spectroscopy and cyclic voltammetry tests indicate that the separation of H₂ from the negative electrode may be partly blocked in the former because of the change of the adsorption/desorption behavior of H on the surface of the negative electrode,thus results in an improvement of self-discharge performance of the battery.

2006 National Conference On Corrosion Electrochemistry And Measuring Methods, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Effects Of Forced Convection And Surface Tension During Methanol Droplet Convection,”, V. Raghavan, D. N. Pope, G. Gogos

Combustion Research at University of Nebraska-Lincoln

Effects of Forced Convection and Surface Tension during Methanol Droplet Convection,”

Numerical Simulation Of Fuel Droplet Extinction Due To Forced Convection,", D. N. Pope, G. Gogos

Combustion Research at University of Nebraska-Lincoln

Numerical Simulation of Fuel Droplet Extinction Due to Forced Convection,"

A New Multicomponent Diffusion Formulation For The Finite-Volume Method: Application To Convective Droplet Combustion, D. N. Pope, G. Gogos

Combustion Research at University of Nebraska-Lincoln

A New Multicomponent Diffusion Formulation for the Finite-Volume Method: Application to Convective Droplet Combustion

Combustion Of Moving Droplets And Suspended Droplets: Transient Numerical Results, D. N. Pope, D. Howard, K. Lu, G. Gogos

Combustion Research at University of Nebraska-Lincoln

Combustion of Moving Droplets and Suspended Droplets: Transient Numerical Results

Surface Tension Effects During Low Reynolds Number Methanol Droplet Combustion, V. Raghavan, D. N. Pope, D. Howard, G. Gogos

Combustion Research at University of Nebraska-Lincoln

Surface Tension Effects during Low Reynolds Number Methanol Droplet Combustion

Synthesis And Properties Of Metallic Technetium And Technetium - Zirconium Alloys As A Radioactive Storage Waste Form To Stabilize The Technetium Waste Stream Of The Urex+1 Process, Frederic Poineau, Thomas Hartmann, Kenneth Czerwinski

Waste Forms Campaign (TRP)

In the AFCI program the UREX+1 process is proposed as one of the most promising technique to separate TRU (transuranic elements) form LWR spent nuclear fuel in the years to come. The application of UREX+1 results in good separation of the 5f-transuranics from the 4f-lanthanides, reduced waste volumes by eliminating the uranium content, and reduced waste package costs. Technetium-99 will be separated together with uranium and iodine within the first process steps. After the separation of uranium, technetium and iodine must be immobilized by their incorporation in a suitable waste storage form. Based on recent activities within the AFCI community, …

Preparation Of Spinel Limn2O4 Cathode Materials For Li-Ion Batteries Based On Sol-Gel Process, Xiang-Ming He, Li Wang, Guo-Yun Zhang, Chang-Yin Jiang, Chun-Rong Wan

Journal of Electrochemistry

Spinel LiMn₂O₄ was prepared from CH₃COOLi·2H₂O,Mn(CH₃COO)₂ and adipic acid based on sol-gel process.XRD analysis showed that when the sintering temperature increased,the crystallinity increased,and the capacity also increased.However,its cycleability reached a maximum value at 750 ℃.The sintering duration also influenced on the capacity.The optimized performance was obtained when the sintering was carried out at 750 ℃ for 20 h.Under these conditions,as-prepared spinel LiMn₂O₄  presented the initial discharge capacity of 130 mAh·g^-1 and 125 mAh·g^-1 at 15^th cycle.

Electrochemistry And Structures Of Silicon Surface, Gregory X.Zhang

Journal of Electrochemistry

Accurate control and fabrication of silicon surface structures from atomic scale to micrometer scale,which may be randomly associated with surface roughness or have well defined patterns,is critical for the per-formance and reliability of electronic devices.Electrochemical reactions of silicon in solutions involved in wetcleaning and etching of silicon wafer play an importantrole in determining the structures of silicon surface.Atre-mendous amount of researches have been done in the last several decades to understand and control a range ofcomplex electrochemical reactions at silicon/solution interface and their relations to the resulted surface struc-tures.The findings generated from these research efforts have been compiled and integrated …

Development On Hydriding/Dehydriding Kinetics Of Mg Nano-Materials For Hydrogen Storage, Wei Mo, Hong-Liang Sun, Hai-Chang Zhang, Hua-Bin Yang, Zuo-Xiang Zhou

Journal of Electrochemistry

The development of Mg nano-materials for hydrogen storage in the recent decade has been reviewed in this paper.It was shown the Mg nano-powders prepared by high-energy ball milling showed promising hydriding and dehydriding performance with the transition metal oxides and other types of hydrogen storage alloys(ABx)as the catalysts.

Electrocatalytic Oxidation Of Glucose On Nano Pt/C Electrode, Cui-Lian Chen, Xiao-Lan Wei, Pei Kang Shen

Journal of Electrochemistry

Nano Pt/C electrocatalysts were prepared by intermittent microwave heating method.The electrooxidation of glucose on smooth Pt and～Pt/C electrodes has been studied and compared.The results showed that the electrochemical properties on nano Pt/C were improved due to the reduction of the overpotential and the increase in the kinetic rate.The surface area would be significantly increased when the particle size of the catalyst was reduced to nano-scale,resulting in the increase in the activity.The enhancement in the resistance to poisoning could be explained that the oxygen-containing species are easier to react with poisoning species on nano Pt/C and re-active the electrode.