Engineering Commons^™

Grating Lobe Reduction In Aperiodic Linear Arrays Of Physically Large Antennas, William C. Barott, Paul G. Steffes

Publications

We present performance bounds obtained from the optimization of the sidelobe levels of aperiodic linear arrays. The antennas comprising these arrays are large compared to the distance between neighboring antennas, a case not addressed in previously published work. This optimization is performed in pattern-space and is applicable over a wide range of scan angles. We show that grating lobes can be suppressed even when the elemental antennas are several wavelengths in size, provided that the ratio of the antenna size to the average spacing between the antenna center-points does not exceed 80%.

Airport Bird Hazard Management, Flavio A. C. Mendonca Ph.D.

Publications

Aircraft collisions with birds, also commonly referred to as bird strikes, annually cost the commercial aviation industry in Brazil at least $6 million in direct damage and associated costs and hundreds of hours of aircraft down time. Although the economic costs of wildlife strikes are extreme, the cost in human lives lost when aircraft accidents occur as a result of strikes best illustrates the need for management of the wildlife strike problem. Bird strikes have been an increasing problem for the aviation industry. Air travel has become widespread all over the world. The aircraft has played an important role not …

Volumetric Flank Wear Characterization For Titanium Milling Insert Tools, Uli Burger, Mathew Kuttolamadom, April Bryan, Laine Mears, Thomas Kurfess

Publications

Machining wear models are useful for the prediction of tool life and the estimation of machining productivity. Existing wear models relate the cutting parameters of feed, speed, and depth of cut to tool wear. The tool wear is often reported as changes in flank width or crater depth. However, these one-dimensional wear measurements do not fully characterize the tool condition when tools wear by other types of wear such as notching, chipping, and adhesion. This is especially true when machining difficult-to-machine materials such as titanium. This paper proposes another approach for characterizing tool wear. It is based on taking measurements …

Heavy-Fueled Intermittent Ignition Engines: Technical Issues, Jeffrey Arthur Schneider, Timothy Wilson, Christopher Griffis, Peter Pierpont

Publications

This report contains an overview of the technology and engineering issues with nonturbine heavy-fueled engines for general aviation aircraft and Unmanned Aircraft Systems. In recent years, interest in these types of engines has grown, partly due to the cost, safety, and worldwide availability of gasoline fuels. Within 3 to 5 years, up to five engines will seek Federal Aviation Administration certification as heavy-fuel powerplants. Although there has been some progress, there is no universal standard for certification of these engines (under Title 14 Code of Federal Regulations (CFR) Part 33), or their installation into normal category fixed-wing aircraft or rotorcraft …

Unmanned Aircraft System Propulsion Systems Technology Survey, Christopher Griffis, Timothy Wilson, Jeffrey Schneider, Peter Pierpont

Publications

This technology survey is an investigation of various propulsion systems used in Unmanned Aircraft Systems (UAS). Discussed are existing and near-future propulsion mechanisms of UAS, such as reciprocating piston engines, Wankel rotary engines, gas turbine engines, rocket-powered systems, electric motors, and battery-based systems. Also discussed are systems that use proton exchange membrane fuel cells, photovoltaics, ultracapacitors, and propellers. Each system is described in reference to a larger conceptual framework, with instances and profiles of existing UAS employing the system being described. Advantages and disadvantages of each type of propulsion system are identified along with associated technical issues and their respective …

Waves In Inhomogeneous Solids, Arkadi Berezovski, Mihhail Berezovski, Juri Engelbrecht

Publications

The paper aims at presenting a numerical technique used in simulating the propagation of waves in inhomogeneous elastic solids. The basic governing equations are solved by means of a finite-volume scheme that is faithful, accurate, and conservative. Furthermore, this scheme is compatible with thermodynamics through the identification of the notions of numerical fluxes (a notion from numerics) and of excess quantities (a notion from irreversible thermodynamics). A selection of one-dimensional wave propagation problems is presented, the simulation of which exploits the designed numerical scheme. This selection of exemplary problems includes (i) waves in periodic media for weakly nonlinear waves with …

Aviation Safety Information Analysis And Sharing -- General Aviation (Asias -- Ga), Alan J. Stolzer

Publications

A presentation on the collaborative government and industry initiative on data sharing and analysis to proactively discover safety concerns before accidents or incidents occur, leading to timely mitigation and prevention.

Developing Abrasion Test Standards For Evaluating Lunar Construction Materials, Ryan L. Kobrick, David M. Klaus, Kenneth W. Street

Publications

Operational issues encountered by Apollo astronauts relating to lunar dust were catalogued, including material abrasion that resulted in scratches and wear on spacesuit components, ultimately impacting visibility, joint mobility and pressure retention. Standard methods are being developed to measure abrasive wear on candidate construction materials to be used for spacesuits, spacecraft, and robotics. Calibration tests were conducted using a standard diamond stylus scratch tip on the common spacecraft structure aluminum, Al 6061-T6. Custom tips were fabricated from terrestrial counterparts of lunar minerals for scratching Al 6061-T6 and comparing to standard diamond scratches. Considerations are offered for how to apply standards …

Access Mars: Assessing Cave Capabilities Establishing Specific Solutions: Final Report, Abdul Mohsen Al Husseini, Luis Alvarez Sanchez, Konstantinos Antonakopoulos, Jeffrey (Johannes) Apeldoorn, Kenneth Lowell Ashford Jr., Kutay Deniz Atabay, Sara Langston, Et Al.

Publications

The human race has evolved, grown and expanded through the exploration of Earth. After initial steps on the Moon, our next challenge is to explore the solar system. Mars shows potential for both scientific discovery and future human settlement, and so is a prime candidate for the next leap of human exploration. Such a bold endeavor will be a driver for an unprecedented worldwide cooperative effort and the catalyst for a new era of international, intercultural and interdisciplinary human relations. Scientific and technological progress will also accelerate as mankind is ushered into a new era of space exploration.

Currently proposed …

Dredging And Dredged Material Beneficial Use In Ireland, Colm Sheehan, Joseph R. Harrington, Jerry Murphy

Publications

This article provides an overview of the dredging industry in Ireland which may be small by international standards but is of critical importance to the nation’s Ports and Harbours. Open sea disposal of dredged material is most common, but a range of beneficial uses for the coarser fraction of dredged material has been practiced. Details on different aspects of dredging in Ireland are presented including a review of current beneficial uses. A specific site at Fenit Harbour in Tralee Bay is examined to assess the potential for a specific beneficial use of dredged material using geotubes in breakwater and revetment …

Warning! Engineers In Training: Introducing Middle School Students To Industrial Engineering, Its Usefulness, And Its Applications, M. Grubb, A. Berger, D. Browning, M. Mayorga, Laine Mears

Publications

The McCants Middle School Pre-engineering class is designed to teach engineering skills to students with a predisposition for and interest in math and science. This team’s initiative is to use Industrial Engineering tools to enhance the existing pre-engineering course curriculum. The purpose of this study is to make middle school students better aware of an engineer’s thought process as it pertains to effectively planning and working on projects, and to measure the impact of our influence. Through this study, we want to improve the overall quality of the student’s projects and ultimately increase the retention and quantity of students interested …

A Technology Survey Of Emergency Recovery And Flight Termination Systems For Uas, Richard Stansbury, Wesley Tanis, Timothy Wilson

Publications

For safe flight in the National Airspace System (NAS), either under the current interim rules or under anticipated longer-term regulatory guidelines facilitating unmanned aircraft system (UAS) access to the NAS, the UAS must incorporate technologies and flight procedures to ensure that neither people nor property in the air, on the ground, or on or in the water are endangered by the failure of an onboard component, by inappropriate unmanned aircraft (UA) response to pilot commands, or by inadvertent entry by the UA into prohibited airspace. The aircraft must be equipped with emergency recovery (ER) procedures and technologies that ensure that …

Simulation And Behavior Of Corrosion Deteriorated Reinforced Concrete Members, M. A. Shayanfar, Amir Safiey

Publications

Several reinforced concrete (RC) infrastructures are now crumbling from corrosion of steel bars in concrete. The paper presents the recent advancements in analytical simulation of corrosion aftereffects on behavior of RC members. The model juxtaposes the experimental findings with analytical relationships. The implementation of the model into a nonlinear finite element formulation as well as the experimental and analytical backgrounds are discussed. The abilities of the resulted program have been studied by modeling some experimental specimens showing a reasonable agreement between the analytical and experimental findings.

Safety Management Systems Update And Progress, Alan J. Stolzer

Publications

The Safety Management System (SMS) Day Panel Charge on March 18, 2009, delivered by Dr. Alan Stolzer, was intended to provide participants with references, tools, vocabulary, and encouragement to adopt academic and laboratory curricula that would prepare students for careers in the SMS environment.

Shaft Capacity Of Continuous Flight Auger Piles In Sand, Kenneth Gavin, David Cadogan, Patrick Casey

Publications

This paper presents the results of a series of field experiments performed to study the development of shaft resistance on continuous flight auger piles installed in sand. The test piles were instrumented in order to separate the shaft and base resistance, and to allow the determination of the distribution of shaft resistance along the pile shaft. The tests highlighted the importance of accurate calculation of the shaft resistance for nondisplacement piles. At a typical maximum allowable pile head settlement of 25mm, more than 71% of the pile resistance was provided by shaft friction. Conventional methods of estimating shaft resistance were …

Resources - Thinking Small: Nano Small, David Stricker

Publications

The article provides information on the "Nanooze" magazine publication. It notes the significance of nanotechnology to the development of latest innovations that come from materials at smallest dimensions or at the nanoscale levels. It presents resources published within the publication that explore the emerging issues in nanotechnology.

Integrating Engineering Design Into Technology Education: Georgia's Perspective, Cameron Denson, Todd Kelley, Robert C. Wicklein

Publications

This descriptive research study reported on Georgia’s secondary level (grades 6-12) technology education programs capability to incorporate engineering concepts and/or engineering design into their curriculum. Participants were middle school and high school teachers in the state of Georgia who currently teach technology education. Participants completed a Likert-type online-survey which reported on technology education teacher’s (a) current instructional practices to teach engineering-based instruction, (b) curricular value placed on engineering-based instruction, and (c) instructional needs to teach engineering-based topics. General demographic information was collected from all participants. The results from the study aided in informing the educational community on the perspective of …

A Theoretical Framework To Guide The Re-Engineering Of Technology Education, Todd R. Kelley, Nadia Kellam

Publications

Before leaders in technology education are able to identify a theoretical framework upon which a curriculum is to stand, they must first grapple with two opposing views of the purpose of technology education – education for all learners or career/technical education. Dakers (2006) identifies two opposing philosophies that can serve as a framework for technology education, both inspired by ancient Greece, with the works of Descartes and the birth of positivism. Later reappearing in Pascal’s writings of the mathematical mind, and finally with Rousseau in the mid 1700s, the theoretical arguments of academic verses vocational were established in education, and …

Teacher Challenges To Implement Engineering Design In Secondary Technology Education (Part 3), Todd R. Kelley, Robert C. Wicklein

Publications

This descriptive study examined the current status of technology education teacher practices with respect to engineering design. This article is the third article in a three-part series presenting the results of this study. The first article in the series titled Examination of Engineering Design Curriculum Content highlighted the research findings regarding engineering design curriculum content delivered by technology education teachers. The second article in the series titled Examination of Assessment Practices for Engineering Design Projects in Secondary Technology Education reported technology education teachers’ assessment practices when implementing engineering design projects in the classroom. The sample for this study was drawn …

Examination Of Assessment Practices For Engineering Design Projects In Secondary Education (Part 2), Todd R. Kelley, Robert C. Wicklein

Publications

There is a growing interest in the topic of engineering design for technology education. At the 2007 and 2008 International Technology Education Association (ITEA) conference held in San Antonio, over 80 presentations were related to engineering topics. Further evidence of the influence and impact of engineering design content comes from the large number of well documented curriculum projects designed to infuse engineering content into technology education such as Engineering by Design; Project ProBase; Project Lead the Way, and Introduction to Engineering (Dearing & Daugherty, 2004). Likewise, state curriculum standards exist for the teaching of engineering design in technology education (Massachusetts …

Examination Of Assessment Practices For Engineering Design Projects In Secondary Education (Part 1), Todd R. Kelley, Robert C. Wicklein

Publications

The following descriptive study was designed to determine the national status of secondary technology education curriculum content and assessment practices as they relate to engineering design. The results of this study were divided into a three-part article series. Although this study focused on the larger construct of the national status of the infusion of engineering design into technology education, three separate sub-constructs emerged. The three sub-constructs were: a) status of engineering design curriculum content; b) the status of assessment practices of engineering design projects, and c) what selected challenges are identified by secondary technology educators in teaching engineering design.

Using Engineering Cases In Technology Education, Todd R. Kelley

Publications

The article discusses issues related to the use of engineering case studies in technology education in K-12 classrooms. Experts from K-12 education, universities, industry and U.S. government officials came to an agreement on the need to implement engineering in K-12 schools. In relation to the proposed use of engineering case studies in technology education, several definitions of the term "design case studies." The presentation of cases using multimedia formats is also cited as a powerful format of engineering design cases.

Motivation While Designing In Engineering And Technology Education Impacted By Academic Preparation, Nathan Mentzer, Kurt Becker

Publications

The purpose of this study was to determine if high school students’ academic preparation was correlated with change in motivation during an engineering design challenge. The research was conducted in a high school classroom in which elements of engineering design were taught in a technology education context to eleventh-grade student from diverse academic backgrounds (measured by grade point average [GPA]). Participant motivation was assessed by the California Measure of Mental Motivation (CM3). The CM3 measures student motivation to apply critical thinking skills and reasoning to solve problems in five subscales: mental focus, learning orientation, creative problem solving, cognitive integrity, and …

Delivering Core Engineering Concepts To Secondary Level Students, Chris Merrill, Rodney L. Custer, Jenny Daugherty, Martin Westrick, Yong Zeng

Publications

Within primary and secondary school technology education, engineering has been proposed as an avenue to bring about technological literacy (Lewis, 2005; Dearing & Daugherty, 2004). Different initiatives such as curriculum development projects (i.e., Project ProBase and Project Lead The Way) and National Science Foundation funded projects such as the National Center for Engineering and Technology Education (NCETE) have been developed to infuse engineering into primary and secondary education. For example, one key goal of the technology teacher education component of NCETE is to impact the focus and content of the technology education field at the secondary level (National Center for …

Essential Concepts Of Engineering Design Curriculum In Secondary Technology Education, Robert G. Wicklein, Phillip C. Smith Jr., Soo Jung Kim

Publications

Technology education is a field of study that seeks to promote technological literacy for all students. According to a recent study, in the United States, technology education is part of the state framework for 38 states, there are approximately 35,909 middle or high school technology teachers, and technology education is most frequently an elective course (Meade & Dugger, 2004). Indeed, students have an opportunity to learn about the processes and knowledge related to technology that are needed to solve problems and extend human capabilities through technology education. Wright and Lauda (1993) defined technology education as a program designed to help …

Singular Superposition/Boundary Element Method For Reconstruction Of Multi-Dimensional Heat Flux Distributions With Application To Film Cooling Holes, Mahmood Silieti, Eduardo Divo, Alain J. Kassab

Publications

A hybrid singularity superposition/boundary element-based inverse problem method for the reconstruction of multi-dimensional heat flux distributions is developed. Cauchy conditions are imposed at exposed surfaces that are readily reached for measurements while convective boundary conditions are unknown at surfaces that are not amenable to measurements such as the walls of the cooling holes. The purpose of the inverse analysis is to determine the heat flux distribution along cooling hole surfaces. This is accomplished in an iterative process by distributing a set of singularities (sinks) inside the physical boundaries of the cooling hole (usually along cooling hole centerline) with a given …

Invited Article: Data Analysis Of The Floating Potential Measurement Unit Aboard The International Space Station, Aroh Barjatya, Charles M. Swenson, Donald C. Thompson, Kenneth H. Wright

Publications

We present data from the Floating Potential Measurement Unit (FPMU) that is deployed on the starboard truss of the International Space Station. The FPMU is a suite of instruments capable of redundant measurements of various plasma parameters. The instrument suite consists of a floating potential probe, a wide-sweeping spherical Langmuir probe, a narrow-sweeping cylindrical Langmuir probe, and a plasma impedance probe. This paper gives a brief overview of the instrumentation and the received data quality, and then presents the algorithm used to reduce I-V curves to plasma parameters. Several hours of data are presented from August 5, 2006 and March …

Analyzing The Impact Of A Virtual Machine On A Host Machine, Greg Dorn, Chris Marberry, Scott Conrad, Philip Craiger

Publications

As virtualization becomes more prevalent in the enterprise and in personal computing, there is a great need to understand the technology as well as its ramifications for recovering digital evidence. This paper focuses on trace evidence related to the installation and execution of virtual machines (VMs) on a host machine. It provides useful information regarding the types and locations of files installed by VM applications, the processes created by running VMs and the structure and identity of VMs, ancillary files and associated artifacts.