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Analysis Of Periodic Structures Using Finite-Difference Time-Domain Method, Khaled ElMahgoub 2010 University of Mississippi

Analysis Of Periodic Structures Using Finite-Difference Time-Domain Method, Khaled Elmahgoub

Electronic Theses and Dissertations

Periodic structures are of great importance in electromagnetics these days due to their wide range of applications such as frequency selective surfaces (FSS), electromagnetic band gap, periodic absorbers, metamaterials and many others. The aim of this work is to develop several algorithms to analyze different types of electromagnetic periodic structures using the constant horizontal wavenumber finite-difference time-domain periodic boundary condition (FDTD/PBC). A new FDTD/PBC approach is introduced to analyze the scattering properties of general skewed grid periodic structures. The approach is simple to implement and efficient in terms of both computational time and memory usage. In addition, an ...


Variability In Resilient Modulus Of Reclaimed Asphalt Pavement As Base Layer And Its Impact On Flexible Pavement Performance, Mohamed Attia, Magdy Abdelrahman 2010 Missouri University of Science and Technology

Variability In Resilient Modulus Of Reclaimed Asphalt Pavement As Base Layer And Its Impact On Flexible Pavement Performance, Mohamed Attia, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The use of reclaimed asphalt pavement (RAP) as a base layer is gaining popularity, but there are gaps in the literature about its material performance. One problem not well investigated is the variability in the resilient modulus (MR) of RAP as a base layer, as compared with typical granular material, and the impact of this variability on pavement performance. Selection of one MR value has its own variability, beyond the expected variability in the base layer R that results from the use of aggregates with different qualities. This paper investigates the effect of three sources of variability to ...


Modeling The Effect Of Moisture On Resilient Modulus Of Untreated Reclaimed Asphalt Pavement, Mohamed Attia, Magdy Abdelrahman 2010 Missouri University of Science and Technology

Modeling The Effect Of Moisture On Resilient Modulus Of Untreated Reclaimed Asphalt Pavement, Mohamed Attia, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The use of reclaimed asphalt pavement (RAP) as a base layer is increasing as quality aggregate becomes scarcer and more expensive. Moisture content is known to have a great impact on the resilient modulus (MR) of granular materials, and several researchers have devoted effort to develop and verify analytical models to describe that impact. Limited work has been done to quantify the effect of moisture content on RAP as a base layer. It has not been determined whether the existence of aged binder will allow designers to use the same analytical models developed for granular materials. This study investigated ...


A New Class Of Attacks On Time Series Data Mining, Ye Zhu, Yongjian Fu, Huirong Fu 2010 Cleveland State University

A New Class Of Attacks On Time Series Data Mining, Ye Zhu, Yongjian Fu, Huirong Fu

Electrical Engineering & Computer Science Faculty Publications

Traditional research on preserving privacy in data mining focuses on time-invariant privacy issues. With the emergence of time series data mining, traditional snapshot-based privacy issues need to be extended to be multi-dimensional with the addition of time dimension. We find current techniques to preserve privacy in data mining are not effective in preserving time-domain privacy. We present the data flow separation attack on privacy in time series data mining, which is based on blind source separation techniques from statistical signal processing. Our experiments with real data show that this attack is effective. By combining the data flow separation method and ...


Casing Pipe Damage Detection With Optical Fiber Sensors: A Case Study In Oil Well Constructions, Zhi Zhou, Jianping He, Minghua Huang, Jun He, Genda Chen 2010 Missouri University of Science and Technology

Casing Pipe Damage Detection With Optical Fiber Sensors: A Case Study In Oil Well Constructions, Zhi Zhou, Jianping He, Minghua Huang, Jun He, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Casing pipes in oil well constructions may suddenly buckle inward as their inside and outside hydrostatic pressure difference increases. For the safety of construction workers and the steady development of oil industries, it is critically important to measure the stress state of a casing pipe. This study develops a rugged, real-time monitoring, and warning system that combines the distributed Brillouin Scattering Time Domain Reflectometry (BOTDR) and the discrete fiber Bragg grating (FBG) measurement. The BOTDR optical fiber sensors were embedded with no optical fiber splice joints in a fiber-reinforced polymer (FRP) rebar and the FBG sensors were wrapped in epoxy ...


Condition Assessment Of Bill Emerson Memorial Cable-Stayed Bridge Under Postulated Design Earthquake, Dongming Yan, Wenjian Wang, Genda Chen, Bryan A. Hartnagel 2010 Missouri University of Science and Technology

Condition Assessment Of Bill Emerson Memorial Cable-Stayed Bridge Under Postulated Design Earthquake, Dongming Yan, Wenjian Wang, Genda Chen, Bryan A. Hartnagel

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, a three-dimensional finite element model of the Bill Emerson Memorial cable-stayed bridge was developed and validated with the acceleration data recorded during the M4.1 earthquake of May 1, 2005, in Manila, Arkansas. The model took into account the geometric nonlinear properties associated with cable sagging and soil-foundation-structure interaction. The validated model was used to evaluate the performance of a seismic protective system, the behavior of cable-stayed spans, and the accuracy of two simplified bridge models that have been extensively used by the structural control community. The calculated natural frequencies and mode shapes correlated well with the ...


Bridge Lessons Learned From The Wenchuan China, Earthquake, W. Phillip Yen, Genda Chen, Mark Yashinski, Youssef M. A. Hashash, Curtis J. Holub, Kehai Wang, Xiaodong Guo 2010 Missouri University of Science and Technology

Bridge Lessons Learned From The Wenchuan China, Earthquake, W. Phillip Yen, Genda Chen, Mark Yashinski, Youssef M. A. Hashash, Curtis J. Holub, Kehai Wang, Xiaodong Guo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A strong earthquake of M7.9 occurred in Wenchuan County in Sichuan Province, China, on May 12, 2008. This paper presents the field observations on various types of bridge damages, including unseating of girders, longitudinal and transverse offset of decks, pounding at expansion joints, shear key failure, bearing displacement, column shear, and flexible cracks. Plausible causes of damages and collapses are discussed and the lessons learned from this event are briefly summarized. Some of the postearthquake temporary constructions are also reported.


Theory Of Breakup Of Core Fluids Surrounded By A Wetting Annulus In Sinusoidally Constricted Capillary Channels, Igor A. Beresnev, Wen Deng 2010 Missouri University of Science and Technology

Theory Of Breakup Of Core Fluids Surrounded By A Wetting Annulus In Sinusoidally Constricted Capillary Channels, Igor A. Beresnev, Wen Deng

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Analysis of core-annular dynamics in the presence of base flow for arbitrary fluid viscosities leads to an equation describing the temporal evolution of the fluid/fluid interface. The equation follows from the conservation of mass in the "small-slope" approximation. Its useful applications occur, for example, in chemical engineering and petroleum recovery. The nonlinear equation allows inexpensive numerical analysis. For sinusoidally constricted pores, a purely geometric criterion exists that enables or prohibits the core-fluid breakup in the necks of the constrictions. The geometrically favoring condition sets up capillary-pressure gradients that ensure a continuous outflow of the core fluid from the necks ...


The Challenges Of Wastewater Irrigation In Developing Countries, M. Qadir, D. Wichelns, L. Raschid-Sally, Peter G. McCornick, P. Drechsel, A. Bahri, P. S. Minhas 2010 International Center for Agricultural Research in the Dry Areas

The Challenges Of Wastewater Irrigation In Developing Countries, M. Qadir, D. Wichelns, L. Raschid-Sally, Peter G. Mccornick, P. Drechsel, A. Bahri, P. S. Minhas

Water for Food Faculty Publications

The volume of wastewater generated by domestic, industrial, and commercial sources has increased with population, urbanization, improved living conditions, and economic development. The productive use of wastewater has also increased, as millions of small-scale farmers in urban and peri-urban areas of developing countries depend on wastewater or wastewater-polluted water sources to irrigate high-value edible crops for urban markets, often as they have no alternative sources of irrigation water. Undesirable constituents in wastewater can harm human health and the environment. Hence, wastewater irrigation is an issue of concern to public agencies responsible for maintaining public health and environmental quality. For diverse ...


Challenges And Prospects Of Sustainable Groundwater Management In The Indus Basin, Pakistan, Asad Sarwar Qureshi, Peter G. McCornick, A. Sarwar, Bharat R. Sharma 2010 International Water Management Institute

Challenges And Prospects Of Sustainable Groundwater Management In The Indus Basin, Pakistan, Asad Sarwar Qureshi, Peter G. Mccornick, A. Sarwar, Bharat R. Sharma

Water for Food Faculty Publications

In Pakistan, on-demand availability of groundwater has transformed the concept of low and uncertain crop yields into more assured crop production. Increased crop yields have resulted in food security and improved rural livelihoods. However, this growth has also led to problems of overdraft, falling water tables, and degradation of groundwater quality, and yields generally remain well below potential levels. Over the last three decades, Pakistan has tried several direct and indirect management strategies for groundwater management. However the success has been limited. This paper argues that techno-institutional approaches such as introducing water rights, direct or indirect pricing, and permit systems ...


Indiana Pavement Preservation Program, Ghim Ping (Raymond) Ong, Tommy E. Nantung, Kumares C. Sinha 2010 Purdue University

Indiana Pavement Preservation Program, Ghim Ping (Raymond) Ong, Tommy E. Nantung, Kumares C. Sinha

JTRP Technical Reports

State highway agencies are facing immense pressure to maintain roads at acceptable levels amidst the challenging financial and economic situations. In recent years, pavement preservation has been sought as a potential alternative for managing the pavement assets, believing that it would provide a cost-effective solution in maintaining infrastructural conditions and meeting user expectations. This study explores the potential of pavement preservation concepts in managing the agency‘s pavement assets by attempting to integrate pavement preservation considerations within the network-level pavement management system. Several elements are studied in the report: (i) determining triggers for pavement preservation treatments for use in a ...


Treatment Guidelines For Pavement Preservation, Jusang Lee, Todd Shields 2010 Indiana Department of Transportation

Treatment Guidelines For Pavement Preservation, Jusang Lee, Todd Shields

JTRP Technical Reports

This project presents pavement treatment practice guidelines and a distress identification manual for the purpose of improving the INDOT pavement preservation practices. The treatment guidelines consist of 10 treatment types for asphalt pavements and composite pavements and 8 treatment types for Portland cement concrete pavement (PCCP). The treatment guidelines include treatment descriptions, benefits, applicable pavement conditions, treatment materials, and treatment procedures. The guidelines are based on information obtained mainly from the INDOT Standard Specification, the INDOT Design Manual, and the INDOT Field Operations Handbook for Crew Leaders. The treatments are covered in the guidelines. The distress identification manual presents the ...


An Assessment Of Delivery Risks In Transportation Projects, Velvet Fitzpatrick, Kumares C. Sinha 2010 Purdue University

An Assessment Of Delivery Risks In Transportation Projects, Velvet Fitzpatrick, Kumares C. Sinha

JTRP Technical Reports

A large number of uncertainties exist in the delivery of highway projects, and it is important to describe the extent so that budgeting and programming can be carried out in a manner that duly accounts for such uncertainties. The study investigates the sources of delivery variability (risk factors) that occur in the period between project proposed date and the letting date. Data on 366 highway projects were collected from the Indiana Department of Transportation Management Information Portal. Using statistical and econometric techniques, the data was analyzed to identify the potential risk factors and to determine the magnitude and direction of ...


Automated Pavement Condition Data Collection Quality Control, Quality Assurance, And Reliability, Ghim Ping (Raymond) Ong, Samy Noureldin, Kumares C. Sinha 2010 Purdue University

Automated Pavement Condition Data Collection Quality Control, Quality Assurance, And Reliability, Ghim Ping (Raymond) Ong, Samy Noureldin, Kumares C. Sinha

JTRP Technical Reports

In recent years, state highway agencies have come to understand the need for high quality pavement condition data at both the project and network levels. At the same time, agencies also realize that they have become too dependent on contractors to ensure the quality of the delivered data without any means to independently assure the quality of these delivered data. This research study therefore aims to investigate the inherent variability of the automated data collection processes and proposes guidelines for an automated data collection quality management program in Indiana. In particular, pavement roughness data (in terms of IRI) and pavement ...


Develop Sonic Infrared Imaging Nde For Local Damage Assessment In Civil Structures, Qi He 2010 Wayne State University

Develop Sonic Infrared Imaging Nde For Local Damage Assessment In Civil Structures, Qi He

Wayne State University Dissertations

Nondestructive Evaluation (NDE) is an interdisciplinary field of study, which is concerned with the development of analysis techniques and measurement technologies for the quantitative characterization of materials, tissues and structures. Ultrasonic IR Imaging is a novel NDE technique, which combines a short ultrasonic pulse excitation and infrared imaging to detect defects in materials and structures. In this technique, a sound pulse with a frequency in the range of 20-40kHz is infused on a target material for a short duration (usually less than one second). The sonic/ultrasonic sound waves travel into the material and cause rubbing and clapping between the ...


Supercritical Carbon Dioxide Processing Of Nano - Clays And Polymer/Clay Nanocomposites, Mihai Manitiu 2010 Wayne State University

Supercritical Carbon Dioxide Processing Of Nano - Clays And Polymer/Clay Nanocomposites, Mihai Manitiu

Wayne State University Dissertations

Effective dispersion of the fillers in a polymer matrix and improvement of polymer-clay interactions are two key challenges in the field of nanocomposites. A novel processing method that utilizes the unique properties of supercritical carbon dioxide (scCO2) to disperse nano-clay and prepare a series of polymer/clay nanocomposites with enhanced properties was explored.

Significant dispersion was achieved using the scCO2 process with Cloisite 10A without the presence of an organic phase as evident by the absence of the diffraction peak in WAXD and the presence of individual tactoids that lost their parallel registry. The expanded flexible structure of the scCO2 ...


Causal Product Knowledge Management, Yun Seon Kim 2010 Wayne State University

Causal Product Knowledge Management, Yun Seon Kim

Wayne State University Dissertations

The US engineering industry base is facing a significant loss of knowledge due to large numbers of employees retiring in the next decade. Problems in various product developments including product design may arise when the expertise is no longer available or the knowledge is forgotten. Also, most of product design knowledge is not reusable, because product design knowledge in an organization remains un-codified. Generally, knowledge-based system can solve or infer these problems. However, knowledge-based systems have been developed solely through the use of rule-based approach, which allows for easy modeling of expert reasoning, but such an approach is not general ...


Robotic Goal-Based Semi-Autonomous Algorithms Improve Remote Operator Performance, Shawn Hunt 2010 Wayne State University

Robotic Goal-Based Semi-Autonomous Algorithms Improve Remote Operator Performance, Shawn Hunt

Wayne State University Dissertations

The focus of this research was to determine if reliable goal-based semi-autonomous algorithms are able to improve remote operator performance or not. Two semi-autonomous algorithms were examined: visual servoing and visual dead reckoning. Visual servoing uses computer vision techniques to generate movement commands while using internal properties of the camera combined with sensor data that tell the robot its current position based on its previous position. This research shows that the semi-autonomous algorithms developed increased performance in a measurable way. An analysis of tracking algorithms for visual servoing was conducted and tracking algorithms were enhanced to make them as robust ...


Finite Element Analysis Of A Nose Gear During Landing, Thoai D. Nguyen 2010 University of North Florida

Finite Element Analysis Of A Nose Gear During Landing, Thoai D. Nguyen

UNF Graduate Theses and Dissertations

Nose gear failure is a high concern in the aviation industries. According to the Federal Aviation Administration reports, 55% of aircraft failures occur during takeoff and landing while 45% of failures occur during flight. The objective of this thesis is to determine the stress behavior and the displacement of a nose gear of an aircraft during landing using structural finite element analysis. The nose gear was first modeled using computer-aided design software and then imported into finite element software. The external forces were determined analytically and the interactions between components were carefully modeled using contact analysis. The tire was modeled ...


Expressiveness Of Streaming String Transducers, Rajeev Alur 2010 University of Pennsylvania

Expressiveness Of Streaming String Transducers, Rajeev Alur

Departmental Papers (CIS)

Streaming string transducers define (partial) functions from input strings to output strings. A streaming string transducer makes a single pass through the input string and uses a finite set of variables that range over strings from the output alphabet. At every step, the transducer processes an input symbol, and updates all the variables in parallel using assignments whose right-hand-sides are concatenations of output symbols and variables with the restriction that a variable can be used at most once in a right-hand-side expression. It has been shown that streaming string transducers operating on strings over infinite data domains are of interest ...


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