Engineering Commons^™

Cs 241-02: Computer Science Ii, Eric Maston

Computer Science & Engineering Syllabi

This course is the second in the Introduction to Computer Science (24X) series. It focuses on object oriented concepts and an introduction to data structures.

Numerical Study On Capillarity- Dominant Free Surface And Interfacial Flows, Zhaoyuan Wang

Mechanical and Aerospace Engineering Dissertations - Archive

The continuum surface force (CSF) method has been extensively employed in the volume-of-fluid (VOF), level set (LS) and front tracking methods to model surface tension forces. Its ability is limited for the surface tension dominant free surface and interfacial flows due to the existence of spurious currents. These currents may lead to disastrous interface instabilities and failure of grid convergence, which are present in all the previous versions of the CSF algorithm. In this study, a coupled level set and volume-of-fluid method (CLSVOF) is employed for interface tracking, which offers more accurate computations of the curvature and the normal vector …

Test Methods And Results For Sensors In A Pre-Crash Detection System, Charles Birdsong, Peter Schuster, John Carlin, Daniel Kawano, William Thompson

Mechanical Engineering

Automobile safety can be improved by anticipating a crash before it occurs and thereby providing additional time to deploy safety technologies. This requires an accurate, fast and robust pre-crash sensor that measures telemetry, discriminates between classes of objects over a range of conditions, and has sufficient range and area of coverage surrounding the vehicle. The sensor must be combined with an algorithm that integrates data to identify threat levels. No one sensor provides adequate information to meet these diverse and demanding requirements. However the requirements can be met with an optimal combination of multiple types of sensors. Previous work considered …

Jamming Sensor Networks: Attack And Defense Strategies, Wenyuan Xu, Wade Trappe, Yanyong Zhang

Faculty Publications

Wireless sensor networks are built upon a shared medium that makes it easy for adversaries to conduct radio interference, or jamming, attacks that effectively cause a denial of service of either transmission or reception functionalities. These attacks can easily be accomplished by an adversary by either bypassing MAC-layer protocols or emitting a radio signal targeted at jamming a particular channel. In this article we survey different jamming attacks that may be employed against a sensor network. In order to cope with the problem of jamming, we discuss a two-phase strategy involving the diagnosis of the attack, followed by a suitable …

Spatial Admittance Selection Conditions For Frictionless Force-Guided Assembly Of Polyhedral Parts In Single Principal Contact, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

By judiciously selecting the admittance of a manipulator, the forces of contact that occur during assembly can be used to guide the parts to proper positioning. This paper identifies conditions for selecting the appropriate spatial admittance to achieve reliable force-guided assembly of polyhedral parts for cases in which a single feature (vertex, edge, or face) of one part contacts a single feature of the other, i.e., all single principal contact cases. These conditions ensure that the motion that results from frictionless contact always instantaneously reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reducing conditions …

Effect Of Firing Temperature And Holding Time On Characterization Of Al/Sic Metal Matrix Composites Produced By Pressureless Infiltration., Anne Zulfia, Myrna Ariati

Makara Journal of Technology

Effect of Firing Temperature and Holding Time on Characterization of Al/SiC Metal Matrix Composites Produced by Pressureless Infiltration. The production of Al-SiC metal matrix composite can be carried out by pressureless metal infiltration processs (PRIMEX). The experiment was conducted using aluminium AC2B ingot as a matrix and 50%Vf SiC powder as a reinforcement which is mixed with 10% Mg powder for wetting agent. The variables of this experiment are holding time and firing temperature to investigate the effect of these conditions on mechanical properties of Al-SiC metal matrix composites. Holding time was conducted for 2,5,8,10,12 hours and firing temperatures was …

Modification Of Bonding Strength Test Of Wc Hvof Thermal Spray Coating On Rocket Nozzle, Bondan T. Sofyan, Haposan J. Pardede, Marizki Stefano, Edi Sofyan

Makara Journal of Technology

Modification of Bonding Strength Test of WC HVOF Thermal Spray Coating on Rocket Nozzle. One way to reduce structural weight of RX-100 rocket is by modifying the nozzle material and processing. Nozzle is the main target in weight reduction due to the fact that it contributes 30 % to the total weight of the structur. An alternative for this is by substitution of massive graphite, which is currently used as thermal protector in the nozzle, with thin layer of HVOF (High Velocity Oxy-Fuel) thermal spray layer. This paper presents the characterization of nozzle base material as well as the modification …

Development Of Fiber-Optic Humidity Sensor Probe With Gelatin Cladding, Akhiruddin Maddu, Kun Modjahidin, Sar Sardy, Hamdani Zain

Makara Journal of Technology

Development of Fiber-Optic Humidity Sensor Probe with Gelatin Cladding. Humidity sensor based on optical fiber with gelatin cladding has been developed. In this humidity sensor probe, the origin cladding of optical fiber is replaced by gelatin coating as humidity sensitive cladding. Testing of the optical fiber sensor probe was conducted by measuring of light intensity transmitted on the optical fiber probe for each variation of different humidity treatments. Response of the optical fiber sensor probe measured from 42%RH to 99%RH, the results show an optical transmission curve varied with relative humidity (RH). Optical transmission in the optical fiber probe increase …

Energy Efficient Process Heating: Managing Air Flow, Kevin Carpenter, J. Kelly Kissock

Mechanical and Aerospace Engineering Faculty Publications

Much energy is lost through excess air flow in and out of process heating equipment. Energy saving opportunities from managing air flow include minimizing combustion air, preheating combustion air, minimizing ventilation air, and reconfiguring openings to reduce leakage.

This paper identifies these opportunities and presents methods to quantify potential energy savings from implementing these energy-savings measures. Case study examples are used to demonstrate the methods and the potential energy savings.The method for calculating savings from minimizing combustion air accounts for improvement in efficiency from increased combustion temperature and decreased combustion gas mass flow rate.

The method for calculating savings from …

Measuring Plant-Wide Energy Savings, J. Kelly Kissock, Carl Eger

Mechanical and Aerospace Engineering Faculty Publications

This paper presents a general method for measuring plant-wide industrial energy savings and demonstrates the method using a case study from an actual industrial energy assessment. The method uses regression models to characterize baseline energy use. It takes into account changes in weather and production, and can use sub-metered data or whole plant utility billing data. In addition to calculating overall savings, the method is also able to disaggregate savings into components, which provides additional insight into the effectiveness of the individual savings measures.

Although the method incorporates search techniques and multi-variable least-squares regression, it is easily implemented using data …

Lessons Learned From An Emergency Bridge Replacement Project, Yong Bai, William R. Burkett, Phillip T. Nash

Civil and Environmental Engineering Faculty Research and Publications

The terrorist attack on September 11, 2001, and subsequent potential threats to U.S. transportation systems have presented an urgent need to develop emergency response plans to quickly react to the possible consequences of extreme events. Extreme events include terrorist attack as well as man-made and natural disasters such as explosions, fires, floods, and earthquakes. The objective of this research was to identify strategies and technologies to quickly restore the use of highway bridges, a critical component of the nation’s transportation network, in case they are damaged or destroyed by extreme events. One of the tasks associated with this research was …

Effect Of Low Molecular Weight Heparin On Fracture Healing In A Stabilized Rat Femur Fracture Model, David J. Hak, Rena L. Stewart, Scott J. Hazelwood

Biomedical Engineering

The purpose of this studywas to evaluate the effect of low molecular weight heparin (LMWH) on fracture healing in a standard stabilized rat femur fracture model. A closed, mid-diaphyseal transverse fracture was created in the right femur of Long-Evans rats after insertion of a 0.8-mm K-wire into the medullarycanal. Animals were randomized to receive either LMWH (70 units/kg dalteparin) oraninjection of normal saline daily for 2 weeks. Animals were sacrificed at 2, 3, and 6 weeks. Fracture healing was assessedbyradiographs, histology, and mechanical testing. There were no significant differences between the control and LMWH groups in the percentage of animalswith …

A Causal Comparative Factorial Analysis Of Factors Affecting Service Level Agreements In A U.S. Navy Enterprise Information Systems Network, Jamie Lee Quintana

Master's Theses and Doctoral Dissertations

This paper presents the results of a research study related to the Navy and Marine Corps Intranet (NMCI). This study used MANOVA and one-way ANOVA, including post hoc tests, to analyze data sets corresponding to service level agreement metrics for over 300 Navy sites. Within the NMCI network, factors size, server farm, Network Operations Center (NOC), area, region, and group are affecting the performance metrics as defined in the service level agreements (SLA). Each one of the factors is statistically disparate for at least one SLA. Checks for normality indicate nonnormal behavior for most data sets. The results, conclusions, and …

High Accuracy Disbond Thickness Estimation Scheme Employing Multiple-Frequency Near-Field Microwave Measurements, Mohamed A. Abou-Khousa, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Microwave nondestructive evaluation (NDE) techniques have shown great potential for disbond detection in multi-layer dielectric structures. However, a quantitative disbond thickness estimation scheme has not been introduced yet. In this paper, we propose a maximum-likelihood (ML) disbond thickness estimation scheme utilizing multiple independent measurements obtained at different frequencies. By simulations and experiments, we show that the proposed scheme produces highly accurate disbond thickness estimates.

Freeze-Spray Processing Of Layered Ceramic Composites (Preprint), Oratai Jongprateep, Q. Fu, A. Abbott, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Thermal gradients and associated stresses are critical in designing with ceramic composites having low thermal conductivity. In order to reduce the stresses from thermal gradients, compositional gradients are employed in designing of composite structures. This study addresses development of freeze-spray process to fabricate layered ceramic structures with controlled layer thickness and microstructural development. The composites were processed by spraying of ceramic slurries with low binder content and relatively high solids loadings up to 40 vol on a cooled substrate. The frozen parts were freeze-dried and sintered at elevated temperatures. The relationship between microstructural development and thermal expansion behavior of Al …

Reversing Ticket Based Probing (Rtbp) Routing For Manet, Turgut Yucel

Electrical & Computer Engineering Theses & Dissertations

The delay-constrained maximum-bandwidth routing problem in MANET (Mobile Ad hoc Networks) is to find the maximum bandwidth path which satisfies a given delay constraint. The research challenge for this problem is that the networking information used for routing may be imprecise. The Ticket-Based Probing (TBP) routing algorithm provides a heuristic approach by using two types of ticket. In this thesis a Reversing Ticket-based Probing (RTBP) routing algorithm is proposed. The RTBP has two novel features compared to the original ticket based probing algorithms. The first feature is using just one type ticket, instead of two types of ticket. RTBP generates …

Passive And Active Nonlinear Control Of Ship Roll Motions Using U-Tube Tanks, Thongchai Phairoh

Mechanical & Aerospace Engineering Theses & Dissertations

A U-tube water tank is first designed to roll a ship floating on still water. The 6-degree of freedom (DOF) dynamic model of U-tube tank is derived and the effects of its parameters on ship roll motion are studied. Numerical simulations show that the U-tube tank is an effective stimulator to roll the ship on still water. For a rolling ship, the U-tube tank can be used as a damper to reduce ship roll motion quickly.

Active control of ship roll motion with a proportional and derivative (PD) controller, linear quadratic regulator (LQR), generalized predictive control (GPC), and deadbeat predictive …

Structural And Magnetic Properties Of La Mn₁₋ₓfeₓo₃ (0 < X < 1.0), X.-D. Zhou, L. R. Pederson, Qingsheng Cai, Jinbo Yang, B. J. Scarfino, M. Kim, William B. Yelon, William Joseph James, Harlan U. Anderson, C. Wang

Materials Science and Engineering Faculty Research & Creative Works

Electronic, structural, and magnetic properties of Mn-doped lanthanum ferrites were studied by neutron diffraction, superconducting quantum interference device, and impedance spectroscopy. Neutron diffraction refinements were performed with the constraint of full La occupancy, which showed the presence of excess oxygen when x < 0.4. Mixed valent Mn cations and cation vacancies, therefore, exist in all the samples. The samples with x > 0.7 are magnetically ordered at room temperature with orthorhombic symmetry (Pbnm). When x < 0.3 the structure is rhombohedral and magnetically disordered above 16 K. The majority carriers, electron holes, correspond to high oxidation states of Mn. The carrier concentration is determined from the Seebeck coefficients, and is a function of temperature and Fe concentration. The measurements of conductivity and Seebeck coefficients show polaron hopping at elevated temperatures.

A Non-Linear Technique For The Enhancement Of Extremely Non-Uniform Lighting Images, Ender Oguslu

Electrical & Computer Engineering Theses & Dissertations

At night scenes, either the low intensity areas that are under poor light or the high intensity areas that are overexposed cannot be clearly seen. Various image processing techniques have been developed to recover the meaningful information under extremely low lighting conditions. Among these, the algorithms based on integrated neighborhood dependency of pixel characteristics and based on the illuminance reflectance model perform well for improving the visual quality of digital images captured under nonuniform and extremely low lighting conditions. Although these techniques perform well in low lighting conditions, they cannot perform well in overexposed regions under dark environments such as …

A Time-Based Vlsi Potentiostat For Ion Current Measurements, Harpreet S. Narula, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

A time-based CMOS integrated potentiostatic control circuit has been designed and fabricated. The design maintains a constant bias potential between the reference and working electrodes for an amperometric chemical sensor. A technique of converting input currents into time for amperometric measurements is proposed. This technique eliminates current amplifying circuitry, reduces matching problems, and increases dynamic range while saving on area and power consumption. Redox currents ranging from 1 pA to 200 nA can be measured with a maximum nonlinearity of ±0.1% over this range. The design can be used to generate cyclic voltammograms for an electrochemical reaction by sweeping the …

Impact Simulation And Analysis Of Sandwich Structures, Daewon Kim

Master's Theses - Daytona Beach

Impact damage on aircraft and spacecraft can be a severe problem that may cause catastrophic results. Several aerospace structures have been used to resist or absorb energy in the occasion of impact. Among these, a sandwich structure has advantages with high stiffness, strength to weight ratio, and its relatively cheap cost. However, finding the impact structural response of a sandwich structure, by performing experiments, has disadvantages. First, impact is a complex problem with a multi-parameter nature and many factors should be considered. Secondly, it is a destructive test and the test subject may be damaged during the test. On the …

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Building Services Engineering

No abstract provided.

Phase Shifts In Frustrated Total Internal Reflection And Optical Tunneling By An Embedded Low-Index Thin Film, R. M.A. Azzam

Electrical Engineering Faculty Publications

Simple and explicit expressions for the phase shifts that p- and s-polarized light experience in frustrated total internal reflection (FTIR) and optical tunneling by an embedded low-index thin film are obtained. The differential phase shifts in reflection and transmission Δr,Δt are found to be identical, and the associated ellipsometric parameters ψr,ψt are governed by a simple relation, independent of film thickness. When the Fresnel interface reflection phase shifts for the pand s polarizations or their average are quarter-wave, the corresponding overall reflection phase shifts introduced by the embedded layer are also quarter-wave for all values of film …

Acoustic Seabed Classification Using Fractional Fourier Transform, Madalina Barbu, Edit J. Kaminsky, Russell E. Trahan

Electrical Engineering Faculty Publications

In this paper we present a time-frequency approach for acoustic seabed classification. Work reported is based on sonar data collected by the Volume Search Sonar (VSS), one of the five sonar systems in the AN/AQS-20. The Volume Search Sonar is a beamformed multibeam sonar system with 27 fore and 27 aft beams, covering almost the entire water volume (from above horizontal, through vertical, back to above horizontal). The processing of a data set of measurement in shallow water is performed using the Fractional Fourier Transform algorithm in order to determine the impulse response of the sediment. The Fractional Fourier transform …

National Internet Repository For Course Portfolios, Paul Savory, Amy M. Goodburn, Amy Nelson Burnett

Department of Industrial and Management Systems Engineering: Faculty Publications

Faculty in higher education are increasingly asked to document, assess, and make public their teaching practices. Course portfolios are a valuable medium for capturing the scholarly work of one’s teaching by combining inquiry into the intellectual work of a course with a careful investigation of the quality of student understanding and performance. It enables a faculty member to document the careful, difficult, and intentional scholarly work of planning and teaching a course. Since a course portfolio can be read, evaluated, and used by others, it offers mechanisms for valuing teaching as scholarship and for improving student learning. This poster will …

Developing And Integrating A Campus Program For Scholarship Of Teaching And Learning Initiatives, Paul Savory, Amy M. Goodburn, Amy Nelson Burnett

Department of Industrial and Management Systems Engineering: Faculty Publications

Based on the successful campus model that the University of Nebraska-Lincoln has developed over ten years, and those of our project consortium partners (Texas A&M, Kansas State University, Indiana University–Bloomington, University of Michigan, and University of Kansas), this panel offers suggestions for creating a campus peer review program designed to promote the intellectual work of teaching generally and the scholarship of teaching and learning more specifically. We offer our perspective on approaches for getting started, establishing the project leadership, seeking funding to support a project, recruiting and supporting faculty participants, developing strategies for running the program, and assessing the project’s …

Flexible Tools For Specifying Design Variation, Trichy Pasupathy, Xiaoping Zhao, Robert Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

This paper describes flexible tools for specifying design variations that are based on nonuniform profile tolerance definitions. These tools specify bounds of design performance that can be used for negotiation among engineers in a collaborative design process. These specification methods allow for the capture of many different design functions that are not easily described with current tool designs. In addition, these specification methods lend themselves to efficient verification methods. Profile tolerance definitions provide the most general variation controls for complex mechanical surfaces. Common design practices and engineering standards for profile tolerances exhibit many weaknesses and limitations. We present a rationale …

A Quantitative Model Of Error Accumulation During Pcr Amplification, Elsje Pienaar, M. Theron, M. Nelson, Hendrik J. Viljoen

Hendrik J. Viljoen Publications

The amplification of target DNA by the polymerase chain reaction (PCR) produces copies which may contain errors. Two sources of errors are associated with the PCR process: (1) editing errors that occur during DNA polymerase-catalyzed enzymatic copying and (2) errors due to DNA thermal damage. In this study a quantitative model of error frequencies is proposed and the role of reaction conditions is investigated. The errors which are ascribed to the polymerase depend on the efficiency of its editing function as well as the reaction conditions; specifically the temperature and the dNTP pool composition. Thermally induced errors stem mostly from …

Controlled Surface-Associated Delivery Of Genes And Oligonucleotides, Tatiana Segura, Lonnie D. Shea, Angela K. Pannier, Zain Bengali, Jae-Hyung Jang, Peter Chung, Brian C. Anderson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A system and methods for controlled gene delivery comprising condensed nucleic acids complexed with polylinkers, wherein the complexes are covalently and/or noncovalently bound to the surface of a substrate capable of supporting cell adhesion. The gene delivery system achieves temporal and spatial control of nucleic acid delivery to a target cell or cells through control of complex density on the surface of the support substrate, and reversibility of the attachment of the polylinker to the support substrate. The system and method of the invention can be used to create spatial patterns of gene expression, and in tissue engineering, high throughput …

Retrofit Of Distillation Columns Using Thermodynamic Analysis, Yaşar Demirel

Papers in Physical Properties

Thermodynamic analysis provides the column grand composite curves and exergy loss profiles, which are becoming readily available for a converged distillation column simulation. For example, the Aspen Plus simulator performs the thermodynamic analysis through its Column–Targeting tool for rigorous column calculations. This study uses the column grand composite curves and the exergy loss profiles obtained from Aspen Plus to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a methanol plant. Effectiveness of the retrofits is also assessed by means of thermodynamics and economics. The methanol plant utilizes two distillation columns …