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2015

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Articles 1201 - 1230 of 7524

Full-Text Articles in Engineering

A Comparative Study Between The Karst Of Hoa Quang, Cao Bang Province, Vietnam And Tuscumbia, Alabama, U.S.A., Gheorghe M. Ponta, Nguyen Xuan Nam, Florentin Stoiciu, Ferenc L. Forray, Viorel Badalita, Lenuta J. Enache, Ioan A. Tudor Oct 2015

A Comparative Study Between The Karst Of Hoa Quang, Cao Bang Province, Vietnam And Tuscumbia, Alabama, U.S.A., Gheorghe M. Ponta, Nguyen Xuan Nam, Florentin Stoiciu, Ferenc L. Forray, Viorel Badalita, Lenuta J. Enache, Ioan A. Tudor

Sinkhole Conference 2015

Some of the most beautiful karst features created by the dissolution of limestones are residual hills with steep or vertical sides rising from a flat plain, known as tower karst. Tower karst to be developed requires a “mean annual temperature of minimum 170C to 180C and 1,000 to 1, 200 mm/m2 of annual rainfall (Jakucs, 1977). Two sites matching this criteria were selected: the karst of Hoa Quang District, Cao Bang Province, Vietnam, and Tuscumbia, Colbert County, Alabama, U.S.A. Preliminary observations regarding similarities and differences between these two sites are presented in this paper. The Hoa Quang karst area is …


A Method Of Mapping Sinkhole Susceptibility Using A Geographic Information System: A Case Study For Interstates In The Karst Counties Of Virginia, Alexandra L. Todd, Lindsay Ivey-Burden Oct 2015

A Method Of Mapping Sinkhole Susceptibility Using A Geographic Information System: A Case Study For Interstates In The Karst Counties Of Virginia, Alexandra L. Todd, Lindsay Ivey-Burden

Sinkhole Conference 2015

Karst terrain is landscape underlain by limestone that has been chemically dissolved by acidic groundwater, producing subsurface voids that pose risks for sinkholes if the overlaying soils can no longer support their own weight and collapse. The western counties of Virginia are heavy in karst due to their natural, geographic boundary of the western Ridge Province and the eastern Blue Ridge Mountain Range. As a result, the Commonwealth of Virginia Hazard Mitigation Plan recommends that the Virginia Department of Transportation (VDOT) develop a method to determine the roadways and regions most susceptible to experiencing sinkholes, in an effort to reduce …


Evaluation Of Cavity Distribution Using Point-Pattern Analysis, Raghav Ramanathan, Yongli Gao, M. Melih Demirkan, Bulent Hatipoglu, Mazen Adib, Michael Rosenmeier, Juan Gutierrez, Hesham El Ganainy Oct 2015

Evaluation Of Cavity Distribution Using Point-Pattern Analysis, Raghav Ramanathan, Yongli Gao, M. Melih Demirkan, Bulent Hatipoglu, Mazen Adib, Michael Rosenmeier, Juan Gutierrez, Hesham El Ganainy

Sinkhole Conference 2015

Presence of solution cavities of different sizes poses major engineering problems in some areas of Abu Dhabi City Municipality (ADM) underlain by soluble rocks such as gypsum, calcarenite, or mudstone. This is especially critical if they are located at a relatively shallow level and are likely to cause settlement or sudden soil collapse. The Gachsaran Formation, which is composed of interlayered mudstone and gypsum, underlies all of the ADM and is known to be vulnerable to cavity formation in the area. The mudstone and gypsum beds within the upper part of the Gachsaran Formation are prone to dissolution. Numerous sinkholes …


Development Of Cavity Probability Map For Abu Dhabi Municipality, Yongli Gao, Raghav Ramanathan, Bulent Hatigoplu, M. Melih Demirkan, Mazen Adib, Juan Gutierrez, Hesham El Ganainy, Daniel Barton Oct 2015

Development Of Cavity Probability Map For Abu Dhabi Municipality, Yongli Gao, Raghav Ramanathan, Bulent Hatigoplu, M. Melih Demirkan, Mazen Adib, Juan Gutierrez, Hesham El Ganainy, Daniel Barton

Sinkhole Conference 2015

Cavity collapse and settlement due to the presence of shallow solution cavities cause significant geotechnical and other engineering problems in certain areas within the Abu Dhabi City Municipality (ADM). A cavity probability map helps to identify regions that are more susceptible to the formation of cavities by identifying and analyzing influential factors contributing to its formation. Information relating to cavities was cataloged and reviewed based on available data from the Geotechnical Information Management System (GIMS), which is a consolidated geotechnical database developed by the ADM. Geological and geotechnical subsurface conditions are obtained from previous site investigation campaigns performed in the …


Media, Sinkholes And The Uk National Karst Database, Vanessa J. Banks Dr, Helen J. Reeves, Emma K. Ward, Emma R. Raycraft, Hannah V. Gow, David J R Morgan, Donald G. Cameron Oct 2015

Media, Sinkholes And The Uk National Karst Database, Vanessa J. Banks Dr, Helen J. Reeves, Emma K. Ward, Emma R. Raycraft, Hannah V. Gow, David J R Morgan, Donald G. Cameron

Sinkhole Conference 2015

The British Geological Survey (BGS) maintains a number of databases that feed into hazard susceptibility assessments, including karst, landslide and mining susceptibility. The winter period from December 2013 to January 2014 was one of, if not the most, exceptional periods of winter rainfall in the last 248 years for England and Wales. During this period the Jet Stream diverted easterly tracking cyclones along a more southerly route than is usual across the United Kingdom (UK). This resulted in south-east and central-southern England experiencing total rainfall values of 372.2 mm for this period, which was the wettest two-month period since 1910. …


The Application Of Passive Seismic Techniques To The Detection Of Buried Hollows, Michael G. Raines, Vanessa J. Banks, Jonathan E. Chambers, Philip E.F. Collins, Peter F. Jones, Dave J.R. Morgan, James B. Riding, Katherine Royse Oct 2015

The Application Of Passive Seismic Techniques To The Detection Of Buried Hollows, Michael G. Raines, Vanessa J. Banks, Jonathan E. Chambers, Philip E.F. Collins, Peter F. Jones, Dave J.R. Morgan, James B. Riding, Katherine Royse

Sinkhole Conference 2015

Pilot studies involving the use of passive seismic techniques in a range of geological settings and applications (e.g., mapping bedrock, studies of soil erosion and Quaternary surficial mapping) have shown that it is a versatile, non-invasive and economic technique. This paper presents the findings of three case studies that used passive seismic techniques for the detection and characterization of buried hollows in carbonate rocks: 1) a buried hollow in the Cretaceous chalk at Ashford Hill in the Kennet Valley, a tributary of the River Thames, UK; 2) buried karst in the foundation excavations for wind turbines in Carboniferous limestone at …


Study On Monitoring And Early Warning Of Karst Collapse Based On Botdr Technique, Zhende Guan Oct 2015

Study On Monitoring And Early Warning Of Karst Collapse Based On Botdr Technique, Zhende Guan

Sinkhole Conference 2015

Brilliouin Optical Time Domain Reflectometer (BOTDR) is a newly developed measurement and monitoring technique, which utilizes Brilliouin spectroscopy and Optical Time Domain Reflectometer (Jiang et al., 2006; Zhang et al., 2009; Xu et al.,2011) to measure strain generated in optical fibers as distributed in the longitudinal direction. This paper introduces the principle and characters of BOTDR technique firstly, and makes an example of karst collapse monitoring at section K14 of highway from Guilin to Yangshuo. And we talk about how to use this technique in underlying karst collapse monitoring in karst highway, discuss environmental factors, like temperature and vehicle dynamic …


Detection Of Voids In Karst Terrain With Full Waveform Tomography, Khiem T. Tran, Michael Mcvay, Trung Dung Nguyen Oct 2015

Detection Of Voids In Karst Terrain With Full Waveform Tomography, Khiem T. Tran, Michael Mcvay, Trung Dung Nguyen

Sinkhole Conference 2015

This paper presents an application of time-domain surface-based waveform tomography for detection of voids in karst terrain. The measured seismic surface wave fields were inverted using a full waveform inversion (FWI) technique, based on a finite-difference solution of 2-D elastic wave equations and the Gauss-Newton inversion method. The FWI was applied to real experimental data sets collected from twelve test lines at a karst site in Florida. Two of the test lines were located next to open karst chimneys to image their extent. Ten other test lines were located in an open and flat area without any void indication from …


Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Edward Hoppe, Andrea Vaccari, Scott Acton, Elizabeth Campbell Oct 2015

Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Edward Hoppe, Andrea Vaccari, Scott Acton, Elizabeth Campbell

Sinkhole Conference 2015

As part of a USDOT-funded study focused on the implementation of satellite-based Interferometric Synthetic Aperture Radar (InSAR) technology, the researchers integrated InSAR-derived point cloud data into the transportation design process within karst terrain. The group’s workflow included initial validation of InSAR data by acquiring over 1.67 million InSAR data points (various “scatterers”) which were then brought into a GIS dataframe and georeferenced to locations of mapped sinkholes. The technique was then applied to the evaluation of karst hazard of within a 40x40 km data frame located in the Valley and Ridge Province of Virginia. The group identified systematic kinematic differences …


The Million Dollar Question: Which Geophysical Methods Locate Caves Best Over The Edwards Aquifer? A Potpourri Of Case Studies From San Antonio And Austin, Texas, Usa, Mustafa Saribudak Oct 2015

The Million Dollar Question: Which Geophysical Methods Locate Caves Best Over The Edwards Aquifer? A Potpourri Of Case Studies From San Antonio And Austin, Texas, Usa, Mustafa Saribudak

Sinkhole Conference 2015

The existence of caves represents a hazard for urban areas. Therefore it is important to know the size, position and depth of caves before building or reconstruction. Cavity imaging using geophysical surveys has become common in the San Antonio area since early 2000 although their use has been going on in other parts of country for the last 25 years. It appears from these studies that the resistivity imaging method has been the primary technique among others, such as gravity, ground penetrating radar (GPR), magnetic, conductivity, and self-potential (natural potential). This study mainly describes resistivity imaging and natural potential data …


Down The Rabbit Hole: Identifying Physical Controls On Sinkhole Formation In The Uk, Tamsin Green Oct 2015

Down The Rabbit Hole: Identifying Physical Controls On Sinkhole Formation In The Uk, Tamsin Green

Sinkhole Conference 2015

Heavy precipitation in the UK in February 2014 induced ground subsidence and consequently a rapid increase in the frequency of sinkhole occurrences. These new sinkhole collapses emphasise the need to further analyse the causes of the increased occurrence by investigating the relative importance of various surficial factors. Malham and the Mendips are two areas of particular interest, since both are underlain by limestone bedrock and are susceptible to subsidence. This is due to limestone being primarily permeable in joints, and so it dissolves to form an extensive network of karstic caves. It was therefore useful to compare two sites of …


Karst Paleo-Collapses And Their Impacts On Mining And The Environment In Northern China, Gongyu Li, Wanfang Zhou Oct 2015

Karst Paleo-Collapses And Their Impacts On Mining And The Environment In Northern China, Gongyu Li, Wanfang Zhou

Sinkhole Conference 2015

Karst paleo-collapses are unique collapse structures widely found in the coal measures of northern China. Their geometric dimensions and internal properties indicate that a compound dissolution of carbonate and gypsum rocks may contribute to their formation. When these collapses are permeable to groundwater flow, they hydraulically connect the coal seams and the karst aquifers, which is a pre-requisite for water inrushes during coal mining. Over the last 40 years, water inrushes through these collapses have caused fatalities, economic losses, and degradation in the environment in northern China. Determination of locations and hydrogeological characteristics of the karst paleo-collapses are essential in …


Hydrocompaction Considerations In Sinkhole Investigations, Edward D. Zisman P.E., P.G., Stephen West Oct 2015

Hydrocompaction Considerations In Sinkhole Investigations, Edward D. Zisman P.E., P.G., Stephen West

Sinkhole Conference 2015

The cause of ground settlement is a significant concern in sinkhole investigations where the potential for shallow and deep-seated instability in the subsurface is a major focus of the investigation. Complicating the investigation is the occurrence of hydrocompaction of surficial soils caused by introduction of large amounts of surface water particularly from improper maintenance of rainfall runoff. This condition is usually followed by the subsequent loss of soil moisture during dry periods. This manuscript will discuss how hydrocompaction plays a role in the analysis of settlement in the investigation of sinkhole loss and how one can distinguish between hydrocompaction settlement …


Successful Foundation Preparations In Karst Bedrock Of The Masonry Section Of Wolf Creek Dam, David M. Robison Oct 2015

Successful Foundation Preparations In Karst Bedrock Of The Masonry Section Of Wolf Creek Dam, David M. Robison

Sinkhole Conference 2015

Extensive foundation preparations during construction of the Wolf Creek Dam concrete masonry section precluded the need for additional rehabilitation to mitigate seepage through karstic limestone bedrock. Wolf Creek Dam on the Cumberland River in southern Kentucky has become well known for karst related seepage issues underneath the embankment section, and yet has had little to no seepage issues associated with the concrete masonry portion of the dam. Post-construction efforts to control seepage underneath the embankment began in 1967 and 1968. Emergency grouting commenced and continued through 1970. Between 1975 and 1979 a more permanent solution of a concrete diaphragm cut-off …


Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett Oct 2015

Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett

Sinkhole Conference 2015

The US Army required construction of a 2,787.1 square meters (30,000 sf) maintenance facility supported on shallow foundations at the Fort Campbell Military Installation. During the subsurface investigation a seven foot air-filled void was encountered in the bedrock within the building footprint. Electrical Resistivity Imaging (ERI) was conducted in an attempt to determine the lateral extent of the encountered void and to establish the general prevalence of karst features at the site. Due to uncertainty in the subsurface conditions, a rock treatment and soil modification program was developed which consisted of a series of targeted exploratory grout holes advanced in …


Predicting Compaction Grout Quantities In Sinkhole Remediation, Edward D. Zisman P.E., P.G. Oct 2015

Predicting Compaction Grout Quantities In Sinkhole Remediation, Edward D. Zisman P.E., P.G.

Sinkhole Conference 2015

Predicting the required quantity of grout needed to remediate a sinkhole-damaged home is a challenging task that involves significant amounts of uncertainty. The difficulty arises from the limited amount of subsurface information that is available to make subsurface predictions particularly in complex karst environments. In typical sinkhole investigations, our understanding of the subsurface is limited by the three to four data points (borings) that provide a small window into actual subsurface conditions. This information is normally obtained from borings and from information inferred by geophysical surveys. In many cases, the information is not sufficient to make accurate predictions of grout …


Monitoring The Threat Of Sinkhole Formation Under A Portion Of Us 18 In Cerro Gordo County, Iowa Using Tdr Measurements, Kevin O'Connor, Matthew Trainum Oct 2015

Monitoring The Threat Of Sinkhole Formation Under A Portion Of Us 18 In Cerro Gordo County, Iowa Using Tdr Measurements, Kevin O'Connor, Matthew Trainum

Sinkhole Conference 2015

Sinkhole formation is a common occurrence in northeast Iowa, and U.S. 18 in Cerro Gordo County was constructed over an area where sinkhole formation had only been locally known. It had not been recorded or identified in the Iowa DNR database at the time. Since 2004, sinkholes have developed along the right of way. Geophysical surveys contributed very little in the identifying the cause. However a Soil Survey (drilling program) identified numerous voids within carbonate bedrock. The soil borings indicated that shale overlying the carbonate rock has been removed/eroded, and resulted in the development of a karst subsurface through the …


Sinkhole Physical Models To Simulate And Investigate Sinkhole Collapses, Mohamed Alrowaimi, Hae-Bum Yun, Manoj Chopra Oct 2015

Sinkhole Physical Models To Simulate And Investigate Sinkhole Collapses, Mohamed Alrowaimi, Hae-Bum Yun, Manoj Chopra

Sinkhole Conference 2015

Florida is one of the most susceptible states for sinkhole collapses due to its karst geology. In Florida, sinkholes are mainly classified as cover subsidence sinkholes that result in a gradual collapse with possible surface signs, and cover collapse sinkholes, which collapse in a sudden and often catastrophic manner. The future development of a reliable sinkhole prediction system will have the potential to minimize the risk to life, and reduce delays in construction due to the need for post-collapse remediation. In this study, different versions of small-scale sinkhole physical models experimentally used to monitor the water levels in a network …


Concepts For Geotechnical Investigation In Karst, Joseph A. Fischer, Joseph J. Fischer Oct 2015

Concepts For Geotechnical Investigation In Karst, Joseph A. Fischer, Joseph J. Fischer

Sinkhole Conference 2015

There seems to be a lack of recognition in the literature that addresses the variety of karst in the United States of America and some of its offshore territories. For example, there are the well-known solutioned carbonates of Florida and the Caribbean, but there are also the somewhat older, harder carbonates of St. Croix, U.S.V.I. Even Florida’s recently deposited karst varies from region to region. There are also the ancient, flat-lying carbonates of the interior craton that often have semi-horizontal cavities resulting from variations in ground water levels affecting bedding and the contorted rocks of the Appalachians with its apparently …


Spatiotemporal Response Of Cvoc Contamination And Remedial Actions In Eogenetic Karst Aquifers, Ingrid Y. Padilla, Vilda L. Rivera, Celys Irizarry Oct 2015

Spatiotemporal Response Of Cvoc Contamination And Remedial Actions In Eogenetic Karst Aquifers, Ingrid Y. Padilla, Vilda L. Rivera, Celys Irizarry

Sinkhole Conference 2015

The northern karst region of Puerto Rico has a long and extensive history of toxic spills, chemical waste, and industrial solvent release into the subsurface. High potential for exposure in the region has prompted aggressive remediation measures, which have extended for over 40 years. Of particular concern is contamination with chlorinated volatile organic compounds (CVOCs) because of their ubiquitous presence and potential health impacts. This work evaluates historical groundwater quality data to assess the spatiotemporal distribution of CVOC contamination in the karst aquifer system of northern Puerto Rico, and its response to remedial action in two superfund sites contaminated with …


Seeps And Springs At A Platteville “Observatory” On The River Bluffs, Bj Bonin, Greg Brick, Julia R. Steenberg Oct 2015

Seeps And Springs At A Platteville “Observatory” On The River Bluffs, Bj Bonin, Greg Brick, Julia R. Steenberg

Sinkhole Conference 2015

Residential building construction along the Mississippi River bluffs in the 1970s created a unique enclosed outcrop of the Late Ordovician Platteville Formation at Lilydale, Minnesota. This outcrop was examined in early 2013 after a newly-formed spring flooded an elevator shaft the previous year, drawing attention to the foundation conditions. The Lexington Riverside property is a six story condominium complex constructed within the top of the bluff. A two-level underground parking garage was built into the bluff. Bedrock was mechanically excavated to accommodate the construction of the building, creating an unweathered rock surface. The space between the structure and the excavated …


Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner Oct 2015

Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner

Sinkhole Conference 2015

The Mitchell Aquifer averages 80m in thickness and underdrains a karst region in the Crawford Upland and Mitchell Plateau region in south-central Indiana (110,000 km2). The Springville Escarpment is a transitional boundary between the upland and plateau. Cave stream linking between cave tiers in the aquifer and correlation of cave tier inception horizons to a base level decline surface is interpreted for the Kirby Watershed, encompassing the prekarst headland of Indian Creek (42km2). The watershed was severed from lower Indian Creek at Eller Col by limestone cavern drainage on the ridge between White River and East Fork. Correlation of recharge …


Tracer Studies Conducted Nearly Two Decades Apart Elucidate Groundwater Movement Through A Karst Aquifer In The Frederick Valley Of Maryland, Keith A. White, Michael K. Cobb, Thomas Aley, Ethan Weikel Oct 2015

Tracer Studies Conducted Nearly Two Decades Apart Elucidate Groundwater Movement Through A Karst Aquifer In The Frederick Valley Of Maryland, Keith A. White, Michael K. Cobb, Thomas Aley, Ethan Weikel

Sinkhole Conference 2015

A pair of groundwater tracer studies at a single karst test site were completed 18 years apart. The results of these studies have provided evidence of both relatively rapid advective transport via conduits and an extreme capacity for dye storage and retardation. The tracer results, coupled with other subsurface investigation data, are used to develop a conceptual model for groundwater movement through this karst aquifer in the Frederick Valley of Maryland, as well as identify implications for remediation. Three fluorescent tracer dyes used in the initial study were detected in several background monitoring locations established for the second study conducted …


Crystallization Engineering As A Route To Epitaxial Strain Control, Andrew R. Akbashev, Aleksandr V. Plokhikh, Dmitri Barbash, Samuel Lofland, Jonathan E. Spanier Oct 2015

Crystallization Engineering As A Route To Epitaxial Strain Control, Andrew R. Akbashev, Aleksandr V. Plokhikh, Dmitri Barbash, Samuel Lofland, Jonathan E. Spanier

College of Science & Mathematics Departmental Research

The controlled synthesis of epitaxial thin films offers opportunities for tuning their functional properties via enabling or suppressing strain relaxation. Examining differences in the epitaxial crystallization of amorphous oxide films, we report on an alternate, low-temperature route for strain engineering. Thin films of amorphous Bi–Fe–O were grown on (001)SrTiO3 and (001)LaAlO3substrates via atomic layer deposition. In situ X-ray diffraction and X-ray photoelectron spectroscopy studies of the crystallization of the amorphous films into the epitaxial (001)BiFeO3 phase reveal distinct evolution profiles of crystallinity with temperature. While growth on (001)SrTiO3 results in a coherently strained film, the same films obtained on (001)LaAlO3 …


Rans Modeling Of Stably Stratified Turbulent Boundary Layer Flows In Openfoam®, Jordan M. Wilson, Subhas K. Venayagamoorthy Oct 2015

Rans Modeling Of Stably Stratified Turbulent Boundary Layer Flows In Openfoam®, Jordan M. Wilson, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Quantifying mixing processes relating to the transport of heat, momentum, and scalar quantities of stably stratified turbulent geophysical flows remains a substantial task. In a stably stratified flow, such as the stable atmospheric boundary layer (SABL), buoyancy forces have a significant impact on the flow characteristics. This study investigates constant and stability-dependent turbulent Prandtl number (Prt) formulations linking the turbulent viscosity (νt) and diffusivity (κt) for modeling applications of boundary layer flows. Numerical simulations of plane Couette flow and pressure-driven channel flow are performed using the Reynolds-averaged Navier-Stokes (RANS) framework with the standard k-ϵ turbulence model. Results are compared with …


Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Andrea Vaccari, Edward Hoppe, Scott Acton, Elizabeth Campbell Oct 2015

Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Andrea Vaccari, Edward Hoppe, Scott Acton, Elizabeth Campbell

Department of Earth and Atmospheric Sciences: Faculty Publications

As part of two USDOT-funded studies focused on the development of satellite-based Interferometric Synthetic Aperture Radar (InSAR) technology, the researchers integrated InSAR-derived point cloud data into the transportation design process to optimize the location of a stormwater management system in a karst terrane. After initial validation, the InSAR data (over 1.67 million data points comprising various “scatterers”) were brought into a GIS dataframe and georeferenced to locations of known sinkholes. This dataset was then used to evaluate karst hazard within a 40x40km data frame located in the Valley and Ridge Province of Virginia. The group identified systematic kinematic differences in …


Small Packages Can Get Big Results, Robert J. Twiggs Oct 2015

Small Packages Can Get Big Results, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Small Packages can get Big Results" from October 16, 2015.


Motion Vector Prediction Using Reselection Among Candidate Set, S. T. Uou, Eric Y. T. Juan, Jim Z. C. Lai Oct 2015

Motion Vector Prediction Using Reselection Among Candidate Set, S. T. Uou, Eric Y. T. Juan, Jim Z. C. Lai

Journal of Marine Science and Technology–Taiwan

For video coding standards with high compression ratio and good image quality, prediction is an essential step. If the prediction is more accurate, then lower bit-rate will be achieved. In this paper, a method is proposed to improve the coding efficiency for motion vectors using predicted motion vector candidate set (PMVCS). PMVCS consists of the motion vectors of blocks, which are the spatial and temporal neighbors of an encoding block. Using the proposed method, a better predicted motion vector can be obtained, which will result in fewer bits allocated for motion vectors. Compared with JIM18.4, the proposed method can reduce …


A Numerical Study Of Liquid Tank And Structure Interaction, Bang-Fuh Chen, Shih-Ming Huang Oct 2015

A Numerical Study Of Liquid Tank And Structure Interaction, Bang-Fuh Chen, Shih-Ming Huang

Journal of Marine Science and Technology–Taiwan

A time-independent finite difference method was used to solve for a fully nonlinear sloshing fluid in a tank mounted on a structure. The interaction between the sloshing fluid and the dynamic response of the structure was investigated. The dynamic response of the structure was calculated using the fourth-order Runge-Kutta method, and the numerical model was extensively validated through comprehensive data comparisons. The tank was tuned to an appropriate depth to length ratio and was used as a tuned liquid damper. Several cases, including large and small structures, were studied. In addition, a vibration control analysis of the tank-structure system in …


Discussion On The Maximum Storm Radius Equations When Calculating Typhoon Waves, Chun-Ming Chang, Hui-Ming Fang, Yung-Wei Chen, Shih-Hsuan Chuang Oct 2015

Discussion On The Maximum Storm Radius Equations When Calculating Typhoon Waves, Chun-Ming Chang, Hui-Ming Fang, Yung-Wei Chen, Shih-Hsuan Chuang

Journal of Marine Science and Technology–Taiwan

In this paper, we conducted a series of numerical experiments to find the most suitable maximum wind speed radii for the parameterized typhoon model. Different maximum wind speed radius equations were used to generate different wind fields, which were then input into the MIKE21 Spectral Wave (SW) model. The wave height results from the MIKE21 SW model were compared with the measured results, and rootmean-square error (RMSE) analysis was conducted to find a good maximum wind speed radius equation for use as the basis for wind field generation in the future. The RMSEs were then scored according to this order. …