Engineering Commons^™

An Integrated System Dynamics Model For Analyzing Behaviour Of The Social-Economic-Climatic System: Model Description And Model Use Guide, Evan G. R. Davies, Slobodan P. Simonovic

Water Resources Research Report

The society-biosphere-climate model described here takes an integrated assessment approach to simulating global change. It consists of eight individual sectors that reproduce the main characteristics of the climate, carbon cycle, economy, land use, population, surface water flow, and water demand and water quality sectors at a global scale, each of which is described individually in the report, both in terms of the theoretical foundation and mathematical basis, and then connected through feedbacks to other sectors in order to recreate the whole system. Several of the sectors build on previous modelling work, but their manner of integration is novel, as are …

Resource Sharing Via Planed Relay For Hwn, Chong Shen, Susan Rea, Dirk Pesch

NIMBUS Articles

We present an improved version of adaptive distributed cross-layer routing algorithm (ADCR) for hybrid wireless network with dedicated relay stations () in this paper. A mobile terminal (MT) may borrow radio resources that are available thousands mile away via secure multihop RNs, where RNs are placed at pre-engineered locations in the network. In rural places such as mountain areas, an MT may also communicate with the core network, when intermediate MTs act as relay node with mobility. To address cross-layer network layers routing issues, the cascaded ADCR establishes routing paths across MTs, RNs, and cellular base stations (BSs) and provides …

Flight Physician - April, 2008, Civil Aviation Medical Association

Browse all Civil Aviation Medical Association Newsletters

A sixteen page newsletter of the Civil Aviation Medical Association. The newsletter provided news about civil aviation medicine and information related to the organization.

Wireless Sensor Network Modeling Using Modified Recurrent Neural Network: Application To Fault Detection, Azzam Issam Moustapha

Doctoral Dissertations

Wireless Sensor Networks (WSNs) consist of a large number of sensors, which in turn have their own dynamics. They interact with each other and the base station, which controls the network. In multi-hop wireless sensor networks, information hops from one node to another and finally to the network gateway or base station. Dynamic Recurrent Neural Networks (RNNs) consist of a set of dynamic nodes that provide internal feedback to their own inputs. They can be used to simulate and model dynamic systems such as a network of sensors.

In this dissertation, a dynamic model of wireless sensor networks and its …

Fabrication Of Bioactive Osteogenic Controlled-Release Systems, Cellular Platforms, And Cellular Capsules Using Layer -By -Layer Nanoassembly, Skylar Stewart-Clark

Doctoral Dissertations

There is an ever-increasing awareness that the field of tissue engineering offers many potential solutions to clinical problems. While advances along these lines have been made, the design and implementation of an "off the shelf" tissue is yet to be realized. Thus, the objectives of this work were largely aimed at the design and fabrication of biocompatible, bioactive structures which could be integrated into existing biomaterial products.

The electrostatic layer-by-layer (LbL) self-assembly technique was used to incorporate biologically relevant molecules within controlled release systems, cell culture platforms, and 3-D cellular capsules. Two delivery systems were investigated to determine the release …

Fast Algorithms For Uncertainty Propagation, And Their Applications To Structural Integrity, Andrzej Pownuk, Jakub Cerveny, Jerald Brady

Departmental Technical Reports (CS)

In many practical situations, we need to know how uncertainty propagates through data processing algorithms, i.e., how the uncertainty in the inputs affects the results of data processing. This problem is important for all types of uncertainty: probabilistic, interval, and fuzzy. From the computational viewpoint, however, this problem is much more complex for interval and fuzzy uncertainty. Therefore, for these types of uncertainty, it is desirable to design faster algorithms.

In this paper, we describe faster algorithms for two practically important situations:

linearization situations, when the approximation errors are small and therefore, the data processing algorithms can be replaced by …

Interfaces, Volume 10, Issue 1 - Spring 2008

INTERFACES: Newsletter of the Nebraska Center for Materials and Nanoscience

CONTENTS
From the Director
Facility Focus: Nano-Fabrication Facility
Recent Achievements of Center Researchers
Magnetic Nanoclusters Put in Order – Insights with Scanning Tunneling Microscopy
NCMN Welcomes Eva Franke Schubert
Research Spotlight: Barry Cheung
UNL Hosts 54th Annual Midwest Solid State Conference
Published Books
Engineers Part of $9 Million Project Studying Cell Context of Genes

Acquisition Of Cardiac Control Parameters From Whole Vagus Nerve Recordings, Marcia A. Pool

Doctoral Dissertations

Heart rate varies continuously depending on the amount of activity being performed or the emotional state of an individual. Both branches of the autonomic nervous system work to alter heart rate depending on the needs of the body. While healthy individuals are capable of altering their heart rate, individuals with certain types of heart disease do not have this ability. For these individuals, cardiac pacemakers are used to alter heart rate. Cardiac pacemakers use sensors to determine the pacing frequency for the heart; however, there is no current optimum sensor. In order to discover a better sensor, this study investigated …

Fabrication Of Fept Ferromagnetic Nanoparticles, Kevin Eugene Elkins

Material Science and Engineering Dissertations - Archive

Fabrication of chemically disordered FePt particles ranging from 2 - 9 nm with a precision of 1 nm has been achieved through modification of key process variables including surfactant concentration, heating rates and the type of iron precursor. In addition, the shape evolution of the FePt nanoparticles during particle growth can be manipulated to give cubic or rod geometries through changes to the surfactant injection sequence and solvent system. The primary method for synthesis of the disordered FePt nanoparticles is the polyol reduction reported by Fievet et al., which has been modified and used extensively for synthesis of diff ering …

Flight Data Analysis And Simulation Of Wind Effects During Aerial Refueling, Timothy Allen Lewis

Mechanical and Aerospace Engineering Theses - Archive

This thesis presents an analysis of data obtained in an automated aerial refueling test flight conducted with a KC-135 as the tanker and a Learjet 25 as the surrogate receiver UAV. The purpose is to identify the wind induced by the tanker wake and its effect on the receiver aircraft. From the available flight data, a direct computation of the winds experienced by the tanker and receiver is carried out. The mean variation of the receiver wind is compared with the tanker wind when the receiver is at the observation and contact positions. This results in the identification of the …

Impact Of Lateral Swell Pressure On Retaining Structure Design Using Expansive Cohesive Backfill, Mark G. Thomas

Civil Engineering Theses - Archive

Since cohesive soils are difficult to drain once becoming saturated, in order to reduce lateral earth pressures exerted by saturated cohesive soils on retaining structures, retaining wall designs most always specify use of drainable granular backfill. However, costs for the importation of granular backfill materials continues to increase due to depletion of these materials in certain areas, and to the ever-increasing costs for material transportation, largely related to increased labor and fuel prices. These factors, together with the costs of removing replaced cohesive materials, and coupled with resource and environmental conservation concerns, are driving efforts to develop reasonable and prudent …

Reduced Switching-Frequency Active Harmonic Elimination For Multilevel Converters, John Chiasson, Zhong Du, Leon M. Tolbert, Burak Ozpineci

Electrical and Computer Engineering Faculty Publications and Presentations

This paper presents a reduced switching-frequency active-harmonic-elimination method (RAHEM) to eliminate any number of specific order harmonics of multilevel converters. First, resultant theory is applied to transcendental equations to eliminate low-order harmonics and to determine switching angles for a fundamental frequency-switching scheme. Next, based on the number of harmonics to be eliminated, Newton climbing method is applied to transcendental equations to eliminate high-order harmonics and to determine switching angles for the fundamental frequency-switching scheme. Third, the magnitudes and phases of the residual lower order harmonics are computed, generated, and subtracted from the original voltage waveform to eliminate these low-order harmonics. …

Low-Voltage Cmos Temperature Sensor Design Using Schottky Diode-Based References, Curtis Cahoon, R. Jacob Baker

Electrical and Computer Engineering Faculty Publications and Presentations

This paper presents the design of a fully differential sigma-delta temperature sensor using Schottky diode-based current references as a replacement for the traditional PN junction diode-based current references. This sensor was designed using the AMI 0.5um process through the MOSIS fabrication organization[l], and the chip performance will be evaluated and compared to the simulated results. The use of the Schottky diode and differential current sensing in the sigma-delta-type sensor allows for lower voltage operation and better noise performance.

The Influence Of Motivation And Investment On The Length Of Time Pilots Fly Into Degraded Weather, Bonnie M. Saxton

Master's Theses - Daytona Beach

Approximately 75% of weather-related accidents result in fatalities and are a primary safety concern in aviation. This study attempted to understand how financial motivation and time investment influence the length of time pilots fly into degraded weather. The sunk-cost effect claims that financially motivated pilots would continue longer when weather is encountered late in the flight. The results revealed that the financially motivated pilots continued longer than the non-financially motivated pilots when weather was encountered early in the flight. These results support the situation assessment hypothesis and cognitive anchoring. Specifically, how pilots assess the situation and utilize information obtained before …

Free-Edge Stresses And Progressive Cracking In Surface Coatings Of Circular Torsion Bars, Xiang-Fa Wu, Yuris A. Dzenis, Kyle W. Strabala

Department of Engineering Mechanics: Faculty Publications

This paper considers the explicit solutions of free-edge stresses near circumferential cracks in surface coatings of circular torsion bars and their application in determining the progressive cracking density in the coating layers. The problem was formulated within the framework of linear elastic fracture mechanics (LEFM). The free-edge stresses near crack tip and the shear stresses in the cross-section of the torsion bar were approached in explicit forms based on the variational principle of complementary strain energy. Criterion for progressive cracking in the coating layer was established in sense of strain energy conservation, and the crack density is thereby estimated. Effects …

Design And Implementation Of Fpga Configuration Logic Block Using Asynchronous Static Ncl, Waleed K. Al-Assadi, T. Tammina, Scott C. Smith, Indira P. Dugganapally

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes the design of a FPGA configurable logic block (CLB) using asynchronous static NULL convention logic (NCL) Library. The proposed design uses three static LUT's for implementing NCL logic functions. Each LUT can be configured to function as any one of the 27 fundamental NCL Static gates. The proposed CLB supports 10 inputs and three different outputs, each with resettable and inverting variations. The CLB has two modes: Configuration mode and operation mode. The static NCL FPGA CLB is simulated at the transistor level using the 1.8 V, 180 nm TSMC CMOS process.

Closed-Form Development Of A Family Of Higher Order Tetrahedral Elements Through The Fourth Order, Sara Elizabeth Mccaslin

Mechanical and Aerospace Engineering Dissertations - Archive

This research is concerned with the development and implementation of a family of tetrahedral elements through the fourth order. The straight-sided tetrahedral elements are developed in closed-form. This work investigates the efficiency of closed-form implementation of stiffness matrices and error estimators compared to numerical implementation. An additional objective is the compaction of closed-form source-code files which require as little storage space as possible, a more pronounced requirement at high p-levels. For the straight-sided elements through p-level 4, the stiffness matrix, equivalent nodal load vectors, and error estimators (based on nodal averaging) are developed using closed-form equations obtained through the use …

Non-Linear Finite Element Dynamic Analysis Of Tapered Hollow Steel Poles For Passive Base Isolation, Tri Le

Civil Engineering Dissertations - Archive

Long tapered poles are commonly used to support Closed Circuit Television (CCTV) Cameras for security and traffic monitoring. Images received from CCTV are normally distorted depending on the wind induced vibration characteristics of the forcing function. To reduce image distortion, three approaches are integrated to optimize the process, which are: (1) development of equations for pole's frequency of vibration in terms of its geometric variables; (2) development of a mechanical damping device to isolate the pole's vibration from that of the camera; and (3) development of an electrical image processing device for image corrections. The identification of a pole's natural …

Dynamic Properties Of Compacted Soils Using Resonant Column With Self-Contained Bender Elements, Roshnara Mohammad

Civil Engineering Theses - Archive

A comprehensive series of resonant column and bender elements tests were simultaneously performed in the developed RC/BE apparatus. RC/BE tests were conducted on compacted specimens of poorly graded sand (SP) and high plasticity clay (CH) prepared at different moisture contents (17.7, 22.1, 25.5, 30.2% by weight for clay, and 5, 10, 15, 20% by weight for sand) and under different confining pressures (0, 2.5, 5.0, and 10.0 psi, or 0, 17.2, 34.4, 69.0 kPa) in order to assess the influence of key environmental factors, such as compaction induced suction and confining pressure, on small-strain stiffness properties of unsaturated soils, such …

Reinforcement Schemes For Cfs Joists Having Web Openings, K. S. Sivakumaran

CCFSS Library (1939 - present)

No abstract provided.

Determination Of Creep Compliance And Tensile Strength Of Hot-Mix Asphalt For Wearing Courses In Missouri, David Newton Richardson, S. M. Lusher

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Creep compliance and indirect tensile (IDT) strength of hot-mix asphalt (HMA) are the two primary inputs to the low-temperature or thermal cracking module in the new Mechanistic-Empirical Pavement Design Guide (M-E PDG) software. Creep compliance is defined as time-dependent strain per unit stress, while IDT strength is best defined as HMA strength when subjected to tension. AASHTO T 322 test protocol was used as reference for this work. However in preparation for the laboratory work performed at the Missouri University of Science and Technology many experts were consulted as to how IDT creep/strength testing and calculations are actually being performed. …

Outperforming The Conventional Scaling Rules In The Quantum-Capacitance Limit, Joachim Knoch, W Riess, Joerg Appenzeller

Other Nanotechnology Publications

We present a study on the scaling behavior of field-effect transistors in the quantum-capacitance limit (QCL). It will be shown that a significant performance improvement in terms of the power delay product can be obtained in devices scaled toward the QCL. As a result, nanowires or nanotubes exhibiting a 1-D transport are a premier choice as active channel materials for transistor devices since the QCL can be attained in such systems.

Wing Optimization Technique Based On Vortex Lattice Theory, Santiago Pinzon

Master's Theses - Daytona Beach

An integrated aerodynamic optimization technique based on vortex lattice theory is being proposed. The technique in this work will aim at optimizing the geometric parameters of a general wing with NACA 65-210 airfoil sections under a low speed aerodynamic regime. This will be completed by performing an aerodynamic analysis based on vortex lattice theory with the objective of satisfying a performance index function. This function will seek to optimize the high lift-to-drag ratio of the wing at cruise velocity, while maximizing theoretical cruise range and minimizing wing weight. The optimization method has been developed using MATLAB and the focus of …

Implementation Of A Low Cost Micro Electro Mechanical Systems Inertial Navigation Solution, Charles Njenga

Master's Theses - Daytona Beach

The purpose of this study is to develop a low cost navigation solution for General Aviation (GA) aircraft and flight testing aircraft. This low cost solution uses a Global Positioning System (GPS) coupled with an Inertial Navigation Solution (INS) to provide a more accurate, stable navigation solution that can be acceptable for aircraft navigation. Lab VIEW was utilized to perform data acquisition and computation. LabVIEW was the backbone software to perform real time computation. MATLAB ® Simulink ® was used to plot graphs for final analysis of the code. A software Kalman Filter was utilized to provide signal stability and …

Practical Evaluation And Analysis Of Passive Uhf Rfid Tags, Ananyaa Gautham

Electrical Engineering Theses - Archive

In this thesis, we have identified the important parameters that impact the performance of passive UHF RFID tags and developed a testing methodology to evaluate and characterize tags. We have also developed the theory to validate the empirical data and analysis. The high performance, low cost and increased storage capacity of the RFID tags has led to the economic adoption of this technology by many industries. Choosing the right tag for the right application might be quite a task with the number of commercially available tags today. It is very important to test the tags and analyze the results to …

Engineering@Nebraska - Spring 2008

Engineering@Nebraska (Alumni Magazine)

Table of Contents:

Front & Center
Engineering Students Enjoy Spain Firsthand: With Nebraska Engineering’s focus on international education, “live and learn” happens in amazing settings. Warm up to the wonders of winter break in Spain.
Spring Break at 35,000 Feet: Nebraska Engineering’s undergraduate research reaches new heights in service to NASA. Ride along with blog posts from an uplifting experience in microgravity.
UNL Experts Build Better Bridges: Atorod Azizinamini—professor of Civil Engineering, researcher and director of UNL's National Bridge Research Organization (NABRO)—leads a team in applying a $2 million grant for safer spans.
Tiny Fibers, Huge Potential: The longterm research …

Strong Hanani-Tutte On The Projective Plane, Michael J. Pelsmajer, Marcus Schaefer, Despina Stasi

Technical Reports

If a graph can be drawn in the projective plane so that every two non-adjacent edges cross an even number of times, then the graph can be embedded in the projective plane.

Incorporation Of Space Syntax Theory In Determining Safe And Efficient Construction Site Layout, Minsuck Cho

Masters Theses

Facility layout is an important to determine a proper arrangement of temporary facilities in a construction site. It significantly impacts productivity and safety of construction. The objectives of layout planning are to minimize travel distance and time, to decrease the facility transportation and setup costs, and to improve site safety. Despite the importance of facility layout, it is often overlooked in the planning phase. Several models have been developed taking some of these factors into consideration; however, construction managers and site planners often regard cost as the most important factor in layout planning and pay less attention to safety and …

Missouri S&T Mote-Based Demonstration Of Energy Monitoring Solution For Network Enabled Manufacturing Using Wireless Sensor Networks (Wsn), James W. Fonda, Maciej Jan Zawodniok, Al Salour, Jagannathan Sarangapani, Donald Miller

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, an inexpensive electric utilities monitoring solution using wireless sensor networks is demonstrated that can easily be installed, deployed, maintained and eliminate unnecessary energy costs and effort. The monitoring solution is designed to support network enabled manufacturing (NEM) program using Missouri University of Science and Technology (MST), formerly the University of Missouri-Rolla (UMR), motes.

Modeling Of Substrate Noise Effects In Dynamic Cmos Circuits, Waleed K. Al-Assadi, S. Burugapalli, Sagar R. Gosavi

Electrical and Computer Engineering Faculty Research & Creative Works

The decrease in the feature size has led to the integration of both digital and analog circuits on the same silicon die which has led to many crosstalk issues. The crosstalk due to the substrate interactions also plagiarizes complete digital systems. This paper lays emphasis on this fact and because of the vulnerability of dynamic CMOS circuits to noise; a brief study of the effects of substrate variations on the performance of the dynamic CMOS circuits is carried out in this paper. The effects of substrate noise at very high frequencies (above 10 GHz) are also depicted in this paper. …