Engineering Commons^™

System Safety Modeling Of Alternative Geofencing Configurations For Small Uas, James T. Luxhoj

International Journal of Aviation, Aeronautics, and Aerospace

As is well known, the integration of small Unmanned Aircraft Systems (sUAS) or “drones” into the National Airspace System (NAS) has captured significant industry, academic, regulatory and media attention. For sUAS that typically fly low and slow, the possibility of a mid-air collision with a nearby general aviation aircraft needs to be studied from a system safety perspective to identify possible hazards and to assess mitigations. The Aviation System Risk Model (ASRM) is a first-generation socio-technical model that uses a Bayesian Belief Network (BBN) methodology to integrate possible hazards to assess a non-linear safety risk metric. Using inductive logic, the …

Thermal Transport Properties Of Dry Spun Carbon Nanotube Sheets, Heath E. Misak, James L. Rutledge, Eric D. Swenson, Shankar Mall

Faculty Publications

The thermal properties of carbon nanotube- (CNT-) sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an …

Overview Of Eps-1 For Spacecraft, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on an "Overview of EPS-1 for Spacecraft" from Febuary 15, 2016.

Overview Of Eps-2 For Spacecraft, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on an "Overview of EPS-2 for Spacecraft" from February 15, 2016.

Model Tests Of Dragging Hall Anchors In Sand, Yu-Xiao Ren, Zhen-Ming Lei, Li-Qiang Sun, Shu-Wang Yan

Journal of Marine Science and Technology–Taiwan

Hall anchors are often used as the main anchors in great medium ships. However, the methods for determining the holding capacity of Hall anchors when being pulled in soil are rarely proposed. In this study, a series of model tests was carried out using four scaled Hall anchor models to determine the kinematic behavior, trajectory, and development rules of the holding capacity of the anchors relative to dragging distances. Moreover, the holding force coefficients of the Hall anchors in sand were identified after the tests

Methods For Designing Partially Inflated Geotubes, Shu-Wang Yan, Jing Chen, Li-Qiang Sun

Journal of Marine Science and Technology–Taiwan

A widely used technique in constructing dikes for land reclamation is to use tubes made of sewn geosynthetic sheets. These tubes are usually filled with slurry comprising soils, such as sand, silt, and clay. The tension stress that develops in geosynthetic tubes during tube filling is the dominant factor considered in constructing safe dikes. Existing design methods are effective for sausage-shaped tube designs; however, they cannot be directly applied in flat tubes, which are commonly used in dike construction. This paper presents a procedure that can determine the relationships among tube size, pumping pressure, unit weight of the slurry, and …

Mechanism And Model Testing Of Pipelay Vessel Roll Affected By Large Period Swells, Jia Li, Zhen-Ming Lei, Li-Qiang Sun, Shu-Wang Yan

Journal of Marine Science and Technology–Taiwan

Pipelay vessels, such as the Hai Yang Shi You 201, have been seriously affected by large period swells in the East China Sea, where the roll amplitude is extremely large for normal pipe lay. Two conditions that can generate dramatic rolls, namely, parametric and synchronous rolling, were analyzed theoretically in this study. Model tests were also performed on the pipelay vessel Hai Yang Shi You 201 with course angles of 0, 30, 60, and 90°in swells of varying periods and wave heights to examine the aforementioned effect. The test data proved that drastic roll is not caused by parametric rolling, …

Pore Pressure Characteristics In Isotropic Consolidated Saturated Clay Under Unloading Conditions, Shu-Wang Yan, Jing-Jing Zhang, Ying-Hui Tian, Li-Qiang Sun

Journal of Marine Science and Technology–Taiwan

When foundations, such as caissons, spudcans, and mudmats, are pulled out from the saturated soft clay foundation, negative excess pore pressure will develop in the interface between the base and the soil. This phenomenon will significantly increase the uplift force. Therefore, estimating the developed negative excess pore pressure in the interface under unloading conditions is important. The development of excess pore pressure was investigated based on the triaxial extension test under isotropic consolidation condition. The method of using the modified Cambridge model to predict the excess pore pressure was programmed and has been proven to be feasible. By associating Henkel’s …

Multi Agv Scheduling Problem In Automated Container Terminal, Jian Jin, Xiao-Hua Zhang

Journal of Marine Science and Technology–Taiwan

In this paper we propose a dynamic multi automated guided vehicle (AGV) scheduling method based on the scheduling properties of automated container terminal handling systems. In multi-AGV scheduling, the composition of AGV handling time and the precedence order of certain tasks are major constraints. Taking these into consideration, we design a genetic algorithm (GA) for a dynamic multi-AGV scheduling model to minimize completion time and standard deviation of handling time of quay cranes (QC), and validated the proposed model through numerical experiment. We expect this model to be significant for multi-agent scheduling of discrete production systems.

Deployment Approach To Nodes Of The Iot For Monitoring Systems In Ports, Yang-Yang Hao, Yi Wu, Bin Yang, You-Fang Huang

Journal of Marine Science and Technology–Taiwan

In order to solve the conflict between higher monitoring quality and lower application costs of the internet of the things (IoT) monitoring system in ports, a mixed integer non-linear programming model was built. Various key factors, such as network scale, cost, representation level, and the deployment of nodes for the balance degree of the IoT, are comprehensively taken into consideration in this programming model. Furthermore, the quantity and deployment solution was solved through a genetic algorithm; in addition, the selection of nodes was evaluated. Simulation results show that the deployment solution is conducive to solve the quality-cost conflict to some …

Anti-Windup Schemes For Nonlinear Active Disturbance Rejection Control In Marine Steam Turbine, Yuan-Qing Wang, Guang Ren, Jun-Dong Zhang

Journal of Marine Science and Technology–Taiwan

Nonlinear characteristics are very common in marine steam turbine, such as control input constraints and external disturbances. Based on the active disturbance rejection control (ADRC), an anti-windup scheme is proposed to eliminate the undesired effects of nonlinear characteristics in the control system. In this scheme, firstly, a method of setting parameter is designed for nonlinear active disturbance rejection control (NLADRC). Then, two kinds of anti-windup schemes are proposed in this paper for NLADRC in the presence of control input constraints and external disturbances. Finally, simulation study is carried out for a first order delay object with actuator constraints, simulation results …

A Fast Automated Vision System For Container Corner Casting Recognition, Chao Mi, Zhiwei Zhang, Youfang Huang, Yang Shen

Journal of Marine Science and Technology–Taiwan

With the development of container port automation, the automated vision systems for containers have been widely used in automated ports. This paper presents a rapid automated vision system for container corner casting recognition. The histograms of oriented gradients (HOG) descriptors are used to preprocess the image of the container and the vectors of HOG are then built. A trained support vector machine (SVM) classifier is applied to recognize the right corner casting of the container. At last, through symmetry, a flipping mirror algorithm is used for quick left corner casting recognition. The experimental results show this algorithm scans and detect …

A Novel Strategy For Stowage Planning Of 40 Feet Containers In Container Terminals, Ning Zhao, Yifan Shen, Mengjue Xia, Jian Jin

Journal of Marine Science and Technology–Taiwan

Owing that the container terminals increasingly secure a crucial position in today’s container transportation, the stowage planning, which is one of the important process during container-loading operations, gradually attracts the attention of terminal operators. In this paper, we discuss the vessel stowage planning problem for 40 feet outbound containers, in which a strategy named ‘ROIR’ is analyzed. By carefully studying the operational flow of vessel stowage, a multiobjective mixed integer programming model is put forward with regard to general principles. Then a specified genetic algorithm is proposed to solve the IP model. An integer encoding technique is employed in the …

Barometer Rising: The Cartagena Protocol On Biosafety As A Model For Holistic International Regulation Of Ocean Fertilization Projects And Other Forms Of Geoengineering, Matthew Hubbard

William & Mary Environmental Law and Policy Review

No abstract provided.

Artificial Perfect Electric Conductor-Perfect Magnetic Conductor Anisotropic Metasurface For Generating Orbital Angular Momentum Of Microwave With Nearly Perfect Conversion Efficiency, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Wei E.I. Sha

Electrical and Computer Engineering Faculty Research & Creative Works

Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel perfect electric conductor-perfect magnetic conductor anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally …

Technical Note: The Impact Of Spatial Scale In Bias Correction Of Climate Model Output For Hydrologic Impact Studies, Edwin P. Maurer, Darren L. Ficklin, W. Wang

Civil, Environmental and Sustainable Engineering

Statistical downscaling is a commonly used technique for translating large-scale climate model output to a scale appropriate for assessing impacts. To ensure downscaled meteorology can be used in climate impact studies, downscaling must correct biases in the large-scale signal. A simple and generally effective method for accommodating systematic biases in large-scale model output is quantile mapping, which has been applied to many variables and shown to reduce biases on average, even in the presence of non-stationarity. Quantile-mapping bias correction has been applied at spatial scales ranging from hundreds of kilometers to individual points, such as weather station locations. Since water …

Four Billion People Facing Severe Water Scarcity, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

Freshwater scarcity is increasingly perceived as a global systemic risk. Previous global water scarcity assessments, measuring water scarcity annually, have underestimated experienced water scarcity by failing to capture the sea- sonal fluctuations in water consumption and availability. We assess blue water scarcity globally at a high spatial resolution on a monthly basis. We find that two-thirds of the global population (4.0 billion people) live under conditions of severe water scarcity at least 1 month of the year. Nearly half of those people live in India and China. Half a billion people in the world face severe water scarcity all year …

Human Activity Prediction By Mapping Grouplets To Recurrent Self-Organizing Map, Qianru Sun, Hong Liu, Mengyuan Liu, Tianwei Zhang

Research Collection School Of Computing and Information Systems

Human activity prediction is defined as inferring the high-level activity category with the observation of only a few action units. It is very meaningful for time-critical applications such as emergency surveillance. For efficient prediction, we represent the ongoing human activity by using body part movements and taking full advantage of inherent sequentiality, then find the best matching activity template by a proper aligning measurement.In streaming videos, dense spatio-temporal interest points (STIPs) are first extracted as low-level descriptors for their high detection efficiency. Then, sparse grouplets, i.e., clustered point groups, are located to represent body part movements, for which we propose …

One-Dimensional Nanostructure And Sensing Applications: Tin Dioxide Nanowires And Carbon Nanotubes, Hoang Anh Tran

Dissertations and Theses

The key challenge for a nanomaterial based sensor is how to synthesize in bulk quantity and fabricate an actual device with insightful understanding of operational mechanisms during performance. I report here effective, controllable methods that exploit the concepts of the "green approach" to synthesize two different one-dimensional nanostructures, including tin oxide nanowires and carbon nanotubes. The syntheses are followed by product characterization and sensing device fabrications as well as sensor performance understanding at the molecular level. Sensor-analyte response and recovery kinetics are also presented.

The first part of the thesis describes bulk-scale synthesis and characterization of tin oxide nanowires by …

Structure Functions, Scaling Exponents And Intermittency In The Wake Of A Wind Turbine Array, Naseem Ali, Aleksandr Sergeyevich Aseyev, Raúl Bayoán Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Hot-wire measurements obtained in a 3 × 3 wind turbine array boundary layer are utilized to analyze high order structure functions, intermittency effects as well as the probability density functions of velocity increments at different scales within the energy cascade. The intermittency exponent is found to be greater in the far-wake region in comparison with the near-wake. At hub height, the intermittency exponent is found to be null. Extended self-similarity scaling exponents of the second, fourth, and fifth order structure functions remain relatively constant as a function of height in the far-wake; whereas in the near-wake, these are highly affected …

Lattice Flexures: Geometries For Stiffness Reduction Of Blade Flexures, Larry L. Howell, Ezekiel G. Merriam

Faculty Publications

Reducing the motion-direction stiffness of compliant mechanisms reduces their actuation effort and simplifies associated static balancing mechanisms. This work introduces a flexure type called lattice flexures and evaluates some of their fundamental properties. Lattice flexures have a reduced bending stiffness when compared to traditional rectangular-section blade flexures of similar size. The motion-direction bending stiffness of two lattice flexure types, called X-type and V-type, are analytically derived, corroborated with finite element analysis, and validated with measurements of physical prototypes. The lattice flexure has the potential to reduce the bending stiffness of some compliant mechanisms by 60-80%, as demonstrated in devices manufactured …

Ryan Summers Seminar Presentation | Biological Engineering, Usu College Of Engineering

College of Engineering News

Upcoming Seminar:

"Production of High-Value Methylxanthines by Metabolically Engineering E. coli."

ENGR 406

Friday: 2/19/16

12:00 - 1:00 PM

Presented by BE Alumni of the Year 2016, Dr. Ryan Summers.

Engineering Week Award Ceremony | Biological Engineering, Usu College Of Engineering

College of Engineering News

The Biological Engineering Department invites you to our annual Recognition Ceremony.

The Bambow: A Bamboo-Cored Carbon-Fiber Composite Bow, Ezekiel G. Merriam

Student Works

Archery is a sport that has benefited from thousands of years of development. Starting with primitive stick-bows, ancient people found they could propel projectiles larger distances and with more effectiveness than by hand or with other mechanical aids. Over the centuries different cultures adopted and advanced different aspects of the technology, including materials, geometry, and manufacturing methods. In the Mechanical Engineering Department at BYU, Nephi's Steel Bow Competition is held annually to challenge engineering students to test their knowledge of mechanics and materials. As a past participant in this competition, I felt building an advanced composite bow would be an …

Sound Attenuation In Amorphous Silica At Frequencies Near The Boson Peak, Zhi Liang, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We Use Molecular Dynamics Phonon Wave Packet (WP) Simulations to Study Acoustic Propagation and Attenuation in Amorphous Silica (A-SiO₂) at Frequencies Near the Boson Peak (BP) Position and Compare Them with the Results of Equilibrium Molecular Dynamics (EMD) Simulations. the Sound Attenuation Coefficients Obtained from WP Simulations Are Generally Consistent with Those from EMD Predictions and Have Reasonable Agreement with the Existing Experimental Data. Near the BP Position, We Found the Frequency-Dependent Sound Attenuation Coefficients for Longitudinal and Transverse Modes Both Follow the Rayleigh-Scattering Fourth Power Law. above the BP Frequency, However, the Propagating Phonon is Essentially Attenuated …

Use Of Galvanic Skin Responses, Salivary Biomarkers, And Self-Reports To Assess Undergraduate Student Performance During A Laboratory Exam Activity, Idalis Villanueva, Maria Valladares, Wade H. Goodridge

Engineering Education Faculty Publications

Typically, self-reports are used in educational research to assess student response and performance to a classroom activity. Yet, addition of biological and physiological measures such as salivary biomarkers and galvanic skin responses are rarely included, limiting the wealth of information that can be obtained to better understand student performance. A laboratory protocol to study undergraduate students' responses to classroom events (e.g., exams) is presented. Participants were asked to complete a representative exam for their degree. Before and after the laboratory exam session, students completed an academic achievement emotions self-report and an interview that paralleled these questions when participants wore a …

The Legacy Of The Tuskegee Airmen, William Norwood

ERAU Prescott Aviation History Program

Learn about the historic Tuskegee Airmen of WW II and how they influenced the first African American pilot hired by United Airlines. Raised in segregated Centralia, IL, he was inspired to fly by his elementary school principal who was a “Red Tail” pilot. He overcame obstacles along the way to become a USAF B-52 pilot before joining UAL where he would retire 31 years later as a DC-10 Captain. Bill shares his love of flying and adventurous spirit in hopes of inspiring others to pursue their dreams.

Direct Band Gap Gallium Antimony Phosphide (GasbXP1-X) Alloys, H. B. Russell, A. N. Andriotis, Madhu Menon, J. B. Jasinski, A. Martinez-Garcia, M. K. Sunkara

Center for Computational Sciences Faculty Publications

Here, we report direct band gap transition for Gallium Phosphide (GaP) when alloyed with just 1–2 at% antimony (Sb) utilizing both density functional theory based computations and experiments. First principles density functional theory calculations of GaSb_xP_1−x alloys in a 216 atom supercell configuration indicate that an indirect to direct band gap transition occurs at x = 0.0092 or higher Sb incorporation into GaSb_xP_1−x. Furthermore, these calculations indicate band edge straddling of the hydrogen evolution and oxygen evolution reactions for compositions ranging from x = 0.0092 Sb up to at least x = 0.065 …

Thermoelastic Waves In Microstructured Solids, Arkadi Berezovski, Mihhail Berezovski

Publications

Thermoelastic wave propagation suggests a coupling between elastic deformation and heat conduction in a body. Microstructure of the body influences the both processes. Since energy is conserved in elastic deformation and heat conduction is always dissipative, the generalization of classical elasticity theory and classical heat conduction is performed differently. It is shown in the paper that a hyperbolic evolution equation for microtemperature can be obtained in the framework of the dual internal variables approach keeping the parabolic equation for the macrotemperature. The microtemperature is considered as a macrotemperature fluctuation. Numerical simulations demonstrate the formation and propagation of thermoelastic waves in …

Information And Communication Technology (Ict) Literacy: Refining A Construct For Assessment, Louis Michael Verdusco

Master's Theses and Doctoral Dissertations

This research effort conceptualized, developed, implemented, and examined the psychometric properties of an Information & Communication Technology (ICT) literacy assessment instrument designed for students entering college. This process began with the development of a working definition of the ICT literacy based on the literature and the input of a panel of experts regarding the proposed literacy sub-constructs and the individual test items. A pilot test was conducted to identify areas for improvement. Once these improvements were incorporated, the final assessment instrument was administered to the freshmen class at a private Midwestern comprehensive university with religious affiliation.

The psychometric aspects of …