Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

131,839 Full-Text Articles 149,706 Authors 44,573,586 Downloads 282 Institutions

All Articles in Engineering

Faceted Search

131,839 full-text articles. Page 3668 of 3687.

Contextual Self-Organizing Maps For Visual Design Space Exploration, Brett Nekolny 2010 Iowa State University

Contextual Self-Organizing Maps For Visual Design Space Exploration, Brett Nekolny

Graduate Theses and Dissertations

Visualization of an optimization problem (i.e the "design space") becomes complex when the number of independent variables of the problem increases beyond two. Unfortunately, realistic optimization problems and their design spaces are often greater than two dimensions and therefore difficult to visualize. In order to create and display in greater than three dimensions it is necessary to use color, size, or symbols to show added dimensions. With the complexity in a visualization that uses these extra dimensional features, an observer is often overloaded with data and it can be difficult to grasp a firm understanding of the relationships therein ...


Control And Diagnosis Of Real-Time Systems Under Finite-Precision Measurement Of Time, Songyan Xu 2010 Iowa State University

Control And Diagnosis Of Real-Time Systems Under Finite-Precision Measurement Of Time, Songyan Xu

Graduate Theses and Dissertations

A discrete event system (DES) is an event-driven system that evolves according to abrupt occurrences of discrete changes (events). The domain of such systems encompasses aspects of many man-made systems such as manufacturing systems, telephone networks, communication protocols, traffic systems, embedded software, asynchronous hardware, robotics, etc.

Supervisory control theory for DESs studies the existence and synthesis of the supervisory controllers, namely, supervisors that restrict the system behaviors by dynamically disabling certain controllable events so that the controlled close-loop system could behave as desired. Extensive work on supervisory control of untimed DESs exists and the extension to the timed setting has ...


Techno-Economic, Location, And Carbon Emission Analysis Of Thermochemical Biomass To Transportation Fuels, Mark Wright 2010 Iowa State University

Techno-Economic, Location, And Carbon Emission Analysis Of Thermochemical Biomass To Transportation Fuels, Mark Wright

Graduate Theses and Dissertations

There are significant technological and systemic challenges faced by today's advanced bio- fuel industry. These challenges stem from the current state-of-technology and from the system (consumer market, infrastructure, environment...) in which this emerging industry is being developed. The state-of-technology will improve with continued efforts in technology development, but novel approaches are required to investigate the systemic challenges that limit the adoption of advanced biofuels.

The motivation of this dissertation is to address the question of how to find cost-effective, sustainable, and environmentally responsible pathways for the production of biofuels. Economic competitiveness, long-term viability, and benign environmental impact are key ...


Microfluidic Single Cell Sorting And Trapping Using Dual Spiral Channels, Pooja Ramesh 2010 Iowa State University

Microfluidic Single Cell Sorting And Trapping Using Dual Spiral Channels, Pooja Ramesh

Graduate Theses and Dissertations

The recent research and development of microfluidic systems for biological and chemical analysis has enabled interfacing and analyzing single or small population of biological cells. In this thesis, we describe a passive microfluidic device with dual spiral geometry for the separation and single cell trapping from a heterogeneous mixture. The device makes use of two spirals to sort and trap cells. Cells flowing in the primary channel experience centrifugal acceleration as they travel along the spiral. A combination of Dean drag force and inertial lift force acting on the cells in the primary channel, cause them to migrate towards the ...


Cast Data Matrix Symbols Performance Characterization, Greg Carl Saveraid 2010 Iowa State University

Cast Data Matrix Symbols Performance Characterization, Greg Carl Saveraid

Graduate Theses and Dissertations

Data matrix symbols are used as a robust means of unique part identification in many industries. Research of cast data matrix symbols has been limited and expected symbol performance unknown. To develop knowledge of cast data matrix symbol performance, the investigation initially focused on feasibility of casting data matrix symbol. Results of a feasibility experiment led to further investigation of cast symbol design expected performance.

Bump marks were evaluated initially due to the inherent ease of production and use in previous cast data matrix applications. The results indicate Bump mark geometry is problematic, due to the inherent nature of shadow ...


Project Management For Complex Transportation Projects, John Owens 2010 Iowa State University

Project Management For Complex Transportation Projects, John Owens

Graduate Theses and Dissertations

The management of complex transportation projects requires a fundamental change in how they are approached. The traditional methodology for managing transportation projects is not adequate for complex projects. The project begins by discussing the transition of project management towards a five-dimensional model that incorporates context and financing dimensions that have previously been regarded merely as risks. The five dimensional model and an extensive literature search pertaining to the management of complex transportation projects assist in mapping the complexity of real-world projects. The main purpose of this research is to present results found on real-world projects that illustrate a new type ...


Propane Earth Materials Drying Techniques And Technologies, Michael Edward Blahut 2010 Iowa State University

Propane Earth Materials Drying Techniques And Technologies, Michael Edward Blahut

Graduate Theses and Dissertations

A feasibility study for the use of propane as a subbase drying technique.

Michael Blahut (1)

Dr. Vernon Schaefer (2)

Dr. Chris Williams (3)

The use of propane as a soil drying technique will be studied to determine the economicand technical feasibility for use in transportation related projects. The need originates from the earthwork portion of a construction schedule, which can be severely delayed if the soil is too wet for compaction. The ultimate goal is develop an implement that can be used in the field and can be adapted to work with existing equipment; i.e. pulled by earth ...


Strains And Polarization Developed During Electric Field-Induced Antiferroelectric To Ferroelectric Phase Transformations In Lead Zirconate-Based Ceramics, Joshua Cody Frederick 2010 Iowa State University

Strains And Polarization Developed During Electric Field-Induced Antiferroelectric To Ferroelectric Phase Transformations In Lead Zirconate-Based Ceramics, Joshua Cody Frederick

Graduate Theses and Dissertations

Widespread adoption of renewable energy sources, such as wind and solar power, will necessitate an efficient way to interface with energy storage devices in order to ensure around-the-clock energy delivery during off-peak hours. Energy storage devices implementing linear dielectric capacitors offer exceptional power density (i.e. rate of charge/discharge), but cannot match the energy density (i.e. storage capacity) of batteries. However, replacing the linear dielectric in capacitors with an antiferroelectric material has the potential to increase the energy density by approximately one order of magnitude. Since the energy is stored via a reversible and diffusionless antiferroelectric-to-ferroelectric phase transformation ...


A Selective Sampling Method For Imbalanced Data Learning On Support Vector Machines, Jong Myong Choi 2010 Iowa State University

A Selective Sampling Method For Imbalanced Data Learning On Support Vector Machines, Jong Myong Choi

Graduate Theses and Dissertations

The class imbalance problem in classification has been recognized as a significant research problem in recent years and a number of methods have been introduced to improve classification results. Rebalancing class distributions (such as over-sampling or under-sampling of learning datasets) has been popular due to its ease of implementation and relatively good performance. For the Support Vector Machine (SVM) classification algorithm, research efforts have focused on reducing the size of learning sets because of the algorithm's sensitivity to the size of the dataset. In this dissertation, we propose a metaheuristic approach (Genetic Algorithm) for under-sampling of an imbalanced dataset ...


Operational Techniques For Implementing Traceability In Bulk Product Supply Chains, Maitri Thakur 2010 Iowa State University

Operational Techniques For Implementing Traceability In Bulk Product Supply Chains, Maitri Thakur

Graduate Theses and Dissertations

Implementation of traceability techniques in bulk food product supply chains is a complex task. A systems approach was used to develop a framework for implementation of traceability in bulk grain supply chain in the United States. A relational database model was developed to facilitate internal traceability at a grain elevator, which is one of the first nodes in a food supply chain. This data management technique could mitigate the bulk grain handling problems by recording all grain lot transformations/activities, including movement, aggregation, segregation, and destruction as well as supplier and customer information. The system can be queried to retrieve ...


Evaluation Of Mechanistic-Based Compaction Measurements For Earthwork Qc/Qa, Jiake Zhang 2010 Iowa State University

Evaluation Of Mechanistic-Based Compaction Measurements For Earthwork Qc/Qa, Jiake Zhang

Graduate Theses and Dissertations

Compaction control for subgrade and base materials used in highway construction is typically based on field tests in comparison to laboratory Proctor tests that determine the relationship between dry unit weight and moisture content. The "optimum" moisture content and maximum dry unit weight are established and then a minimum relative compaction value and moisture content range is specified for acceptance during construction. This approach, although widely accepted, does not directly determine the mechanistic properties of the compacted material (i.e., strength or stiffness). The premise for adopting QA/QC tests that determine mechanistic properties is that the QA/QC operations ...


Evaluating The Cost And Performance Of Vegetative Treatment Systems On Open Beef Feedlots In The Midwestern United States, Bradley J. Bond 2010 Iowa State University

Evaluating The Cost And Performance Of Vegetative Treatment Systems On Open Beef Feedlots In The Midwestern United States, Bradley J. Bond

Graduate Theses and Dissertations

Runoff from open beef feedlots has become an important environmental concern over the last decade. Feedlot runoff has the potential to degrade surface water and groundwater. For these reasons, the U.S. Environmental Protection Agency required concentrated animal feeding operations (CAFOs) to control feedlot runoff resulting from up to and including a 25 year, 24 hour rainfall event. Typical feedlot runoff control systems utilize a containment basin to collect and store feedlot runoff.

In 2003, federal regulations allowed the use of alternative technologies to control feedlot runoff that performed equal to or better than a conventional runoff storage basin on ...


Asphalt Modification By Utilizing Bio-Oil Esp And Tall Oil Additive, Sheng Tang 2010 Iowa State University

Asphalt Modification By Utilizing Bio-Oil Esp And Tall Oil Additive, Sheng Tang

Graduate Theses and Dissertations

Bio-oil is a dark-brown, mobile liquid derived from the thermo-chemical processing of biomass. Bio-oils generally contain water and lignin. Lignin is a highly-available, well-studied carbohydrate derivative known for its antioxidant properties. For asphalt pavements, oxidation can cause deterioration via long-term aging and eventually result in cracking. Therefore, bio-oil could potentially serve as an antioxidant additive in asphalt mixtures. The main objective of this research is to evaluate the effects of lignin-containing bio-oil for utilization in asphalt binders, and attempt to optimize the bio-oil modification formula by adding other additives. Using bio-oil as an antioxidant in asphalt production could prove to ...


Fate Of Agrochemicals In Wood Chip Denitrifying Reactors And Their Impacts On Wood Chip Microbial Ecology, Zehra Esra Ilhan 2010 Iowa State University

Fate Of Agrochemicals In Wood Chip Denitrifying Reactors And Their Impacts On Wood Chip Microbial Ecology, Zehra Esra Ilhan

Graduate Theses and Dissertations

Subsurface tile drainage systems have contributed towards increasing agricultural production, but have also contributed towards water pollution by rapidly transporting excessive nutrient and agrochemicals to surface water and ground water. One of the pollution control strategies is to treat the tile drainage water or the contaminated subsurface water with denitrifying bioreactors. Wood chips have been used in denitrifying bioreactors, providing organic carbon and attachment surface area for denitrifiers. The focus of this research is to investigate fate of agrochemicals in wood chips from the in situ reactors and their potential effects on denitrification and the denitrifiers. The selected agrochemicals for ...


Behavior Characterization And Development Of Lrfd Resistance Factors For Axially-Loaded Steel Piles In Bridge Foundations, Sherif Sayed Abdelsalam 2010 Iowa State University

Behavior Characterization And Development Of Lrfd Resistance Factors For Axially-Loaded Steel Piles In Bridge Foundations, Sherif Sayed Abdelsalam

Graduate Theses and Dissertations

The Federal Highway Administration (FHWA) mandated utilizing the Load and Resistance Factor Design (LRFD) approach for all new bridges initiated in the United States after October 1, 2007. Consequently, significant efforts have been directed by Departments of Transportation (DOTs) in different states towards the development and implementation of the LRFD approach for the design of bridge's deep foundations. The research presented in this thesis is aimed at establishing the LRFD resistance factors for the design of driven pile foundations by accounting for local soil and pile construction practices. Accordingly, regional LRFD resistance factors have been developed for different static ...


Using An Autothrottle To Compare Techniques For Saving Fuel On A Regional Jet Aircraft, Rebecca Marie Johnson 2010 Iowa State University

Using An Autothrottle To Compare Techniques For Saving Fuel On A Regional Jet Aircraft, Rebecca Marie Johnson

Graduate Theses and Dissertations

With rising fuel costs there is an initiative to conserve fuel during fight. Several methods have been proposed to calculate an optimum speed to y during cruise flight to maximize the range of a particular aircraft. This paper compares 11 of these methods using the same aircraft model and discusses how to implement these techniques in an autothrottle. Alternative implementations also include adding the algorithm to the Flight Management System to use during flight planning, or to including it in the databases to use during dispatch calculations. The results show that the speeds calculated by these methods are more fuel ...


Development Of A Sorbent For Carbon Dioxide, Dursun Can Ozcan 2010 Iowa State University

Development Of A Sorbent For Carbon Dioxide, Dursun Can Ozcan

Graduate Theses and Dissertations

The reversible absorption of CO2 by CaO at high temperature is a promising method for capturing and removing CO2 from a hot gas stream. The main challenge facing the use of this method is the deterioration of CO2 absorption capacity when the method is applied over a large number of CO2 absorption/desorption cycles. Although various techniques have been proposed for improving the cyclic stability and performance of calcium based sorbents, a cost effective method is still needed for industrial applications. Therefore, two promising methods for improving the cyclic stability were selected for further investigation. One method is to optimize ...


Analysis Of The Passive Design And Solar Collection Techniques Of The Houses In The 2009 U.S. Department Of Energy's Solar Decathlon Competition, Timothy Robert Lentz 2010 Iowa State University

Analysis Of The Passive Design And Solar Collection Techniques Of The Houses In The 2009 U.S. Department Of Energy's Solar Decathlon Competition, Timothy Robert Lentz

Graduate Theses and Dissertations

The U.S. Department of Energy‘s Solar Decathlon is a competition in which twenty university teams compete to design and build the best completely solar powered house. The biennial competition culminates with the teams reconstructing their houses on the National Mall in Washington, DC for a week of tours and contests. In order for houses to be successful they must take advantage of passive solar design techniques while maximizing the solar energy collected through photovoltaic and thermal collectors.

Internal temperature, internal humidity, overall energy balance, site insolation, site temperature and site humidity data were measured for all twenty houses ...


Applications On Emerging Paradigms In Parallel Computing, Abhinav Sarje 2010 Iowa State University

Applications On Emerging Paradigms In Parallel Computing, Abhinav Sarje

Graduate Theses and Dissertations

The area of computing is seeing parallelism increasingly being incorporated at various levels: from the lowest levels of vector processing units following Single Instruction Multiple Data (SIMD) processing, Simultaneous Multi-threading (SMT) architectures, and multi/many-cores with thread-level shared memory and SIMT parallelism, to the higher levels of distributed memory parallelism as in supercomputers and clusters, and scaling them to large distributed systems as

server farms and clouds. All together these form a large hierarchy of parallelism. Developing high-performance parallel algorithms and efficient software tools, which make use of the available parallelism, is inevitable in order to harness the raw computational ...


Efficient Validation Of Control Flow Integrity For Enhancing Computer System Security, Yong-joon Park 2010 Iowa State University

Efficient Validation Of Control Flow Integrity For Enhancing Computer System Security, Yong-Joon Park

Graduate Theses and Dissertations

Protecting program execution is a critical issue in today's computing systems. Even with all the efforts and dramatic advances in computer system protection, system attacks continue to evolve to explore existing and new vulnerabilities in computer systems. In

this thesis, we propose several ecient and practical methods to validate program control flow integrity as extra layers of system protection. In general, the approach to control flow integrity checking is to detect anomalies of program behavior given that control flow

information is closely coupled with program execution correctness and can be consider as the DNA of a program. It is ...


Digital Commons powered by bepress