Sample records for flexible pavement performance

  1. Flexible Pavement Drainage Monitoring, Performance, and Stability

    Microsoft Academic Search

    Aiwen Feng; Jianfeng Hua; Thomas D. White

    1999-01-01

    The current study is a continuation of the study FHWA\\/IN\\/JTRP project HPR-2078, Locating the Drainage Layer for Flexible Pavements. In this previous study, three test sections were constructed in a new pavement on a by-pass around Fort Wayne, Indiana. These test sections were instrumental to record temperatures, moisture, frost penetration, rainfall and subdrainage system overflow. Collected data and Finite Element

  2. Accounting for the effects of rehabilitation actions on the reliability of flexible pavements: performance modeling and optimization

    E-print Network

    Deshpande, Vighnesh Prakash

    2009-05-15

    A performance model and a reliability-based optimization model for flexible pavements that accounts for the effects of rehabilitation actions are developed. The developed performance model can be effectively implemented in all the applications...

  3. Geotextiles in Flexible Pavement Construction

    ERIC Educational Resources Information Center

    Alungbe, Gabriel D.

    2004-01-01

    People everywhere in the developed world regularly drive on paved roads. Learning about the construction techniques and materials used in paving benefits technology and construction students. This article discusses the use of geosynthetic textiles in pavement construction. It presents background on pavements and describes geotextiles and drainage

  4. Pavement performance prediction using adaptive logic networks

    Microsoft Academic Search

    Mohd Y Nawaiseh

    2002-01-01

    Pavement performance is one of the most important components of the pavement management system. Prediction of the future performance of a pavement section is important in programming maintenance and rehabilitation needs. Models for predicting pavement performance have been developed on the basis of traffic and age. The purpose of this research is to extend the use of a relatively new

  5. Development of Improved Pavement Performance Prediction Models for the Indiana Pavement Management System

    Microsoft Academic Search

    Sedat Gulen; Karen Zhu; John Weaver; Jie Shan; William F. Flora

    2001-01-01

    The Indiana Department of Transportation (INDOT) is increasingly committed to the Pavement Management System. For this reason, updated simple pavement performance prediction models with the least number of explanatory (independent) variables are required to predict the performance of various pavement types for future planning of rehabilitation or replacement. In Indiana, the two main pavement types are jointed concrete pavement (JCP)

  6. Significance of bearing capacity of clayey subgrade in flexible pavement design

    Microsoft Academic Search

    C. N. V. Satyanarayana Reddy; N. V. Rama Moorthy

    2005-01-01

    Clays as subgrades pose serious problems to flexible pavements built over them as they retain moisture for a longer period and possess low strength. Excessive settlements along the wheel tracks on pavement surface and bearing capacity failures in the subgrade soil are often observed in the flexible pavements constructed over such subgrades. So, the present status of flexible pavements in

  7. ANALYSIS OF PERFORMANCE OF THE ULTRA-THIN WHITETOPPING SUBJECTED TO SLOW MOVING LOADS IN AN ACCELERATED PAVEMENT TESTING FACILITY

    Microsoft Academic Search

    Sudarshan Rajan; Jan Olek; Thomas L. Robertson; Tommy Nantung; W. Jason Weiss

    Ultra-Thin Whitetopping (UTW) is rapidly emerging as a technology that can be used for the rehabilitation of deteriorated pavements. To investigate the performance of UTW when they are placed over flexible pavements and subjected to a slow moving load, four whitetopping mixtures were placed over a milled asphalt surface in the Accelerated Pavement Testing (APT) facility of the Indiana Department

  8. Influence of mixture composition on the noise and frictional characteristics of flexible pavements

    NASA Astrophysics Data System (ADS)

    Kowalski, Karol J.

    Both traffic noise and wet pavement-tire friction are mainly affected by the tire/pavement interaction. Existing laboratory test methods allow for evaluation of polishing resistance of the aggregates only. Currently, there is no generally accepted standardized laboratory test method to address noise related issues and the overall frictional properties of pavements (including macrotexture). In this research, which included both laboratory and field components, friction and noise properties of the flexible (asphalt) pavements were investigated. As a part of this study, a laboratory device to polish asphalt specimens was developed and the procedure to evaluate mixture frictional properties was proposed. Following this procedure, forty-six different Superpave mixtures (each utilizing a different aggregate blends), one stone matrix asphalt (SMA) mixture and one porous friction course (PFC) mixture were tested. Six of the above mixes (four Superpave mixtures, SMA mixture and PFC mixture) were selected for laboratory noise testing. This testing was performed using a one-of-a-kind tester called the Tire/Pavement Test Apparatus (TPTA). In addition, the field sections constructed using Superpave, SMA and PFC mixtures were also periodically tested for friction and noise. Field measurements included testing of total of 23 different asphalt and two concrete pavements. The field friction testing was performed using both portable CTM and DFT devices and the (ASTM E 274) locked wheel friction trailer. The laboratory friction testing was performed using CTM and DFT devices only. The results of both field and laboratory friction measurements were used to develop an International Friction Index (IFI)-based frictional requirement for laboratory friction measurements. The results collected in the course of the study indicate that the IFI-based flag values could be successfully used in place of SN-based flag values to characterize frictional characteristics of pavements.

  9. Sensitivity analysis of flexible pavement response and AASHTO 2002 design guide for properties of unbound layers

    E-print Network

    Masad, Sanaa Ahmad

    2004-09-30

    in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 2004 Major Subject: Civil Engineering SENSITIVITY ANALYSIS OF FLEXIBLE PAVEMENT RESPONSE AND AASHTO 2002 DESIGN GUIDE FOR PROPERTIES... (Member) (Head of Department) May 2004 Major Subject: Civil Engineering iii ABSTRACT Sensitivity Analysis of Flexible Pavement Response and AASHTO 2002 Design Guide for Properties...

  10. Porous Pavement in Cold Climates Part: Performance and Cost

    E-print Network

    Porous Pavement in Cold Climates Part: Performance and Cost Onondaga Environmental Institute 17 However, a large number of installations STILL continue to be sub-standard 4 #12;Porous Pavement Design Overview Porous pavements for new and redevelopment are a watershed- based strategy that can both mitigate

  11. Fuzzy optimization BP neural network model for pavement performance assessment

    Microsoft Academic Search

    Yan Liu; Min Sun

    2007-01-01

    This paper discussed the use of fuzzy optimization BP neural network as a management tool for the maintenance of expressway pavement. The algorithm was applied to model pavement performance evaluation, successful in accurately and quickly capturing the high nonlinear characteristics between objective practical data and subjective synthetic evaluations, avoided the neural network activation function's defects of unclear physical meanings. A

  12. Impact of the variation in dynamic vehicle load on flexible pavement responses

    NASA Astrophysics Data System (ADS)

    Ahsanuzzaman, Md

    The purpose of this research was to evaluate the dynamic variation in asphalt pavement critical responses due to dynamic tire load variations. An attempt was also made to develop generalized regression equations to predict the dynamic response variation in flexible pavement under various dynamic load conditions. The study used an extensive database of computed pavement response histories for five different types of sites (smooth, rough, medium rough, very rough and severely rough), two different asphalt pavement structures (thin and thick) at two temperatures (70 F and 104 F), subjected to a tandem axle dual tire at three speeds 25, 37 and 50 mph (40, 60 and 80 km/h). All pavement responses were determined using the 3D-Move Analysis program (Version 1.2) developed by University of Nevada, Reno. A new term called Dynamic Response Coefficient (DRC) was introduced in this study to address the variation in critical pavement responses due to dynamic loads as traditionally measured by the Dynamic Load Coefficient (DLC). While DLC represents the additional varying component of the tire load, DRC represents the additional varying component of the response value (standard deviation divided by mean response). In this study, DRC was compared with DLC for five different sites based on the roughness condition of the sites. Previous studies showed that DLC varies with vehicle speed and suspension types, and assumes a constant value for the whole pavement structure (lateral and vertical directions). On the other hand, in this study, DRC was found to be significantly varied with the asphalt pavement and function of pavement structure, road roughness conditions, temperatures, vehicle speeds, suspension types, and locations of the point of interest in the pavement. A major contribution of the study is that the variation of pavement responses due to dynamic load in a flexible pavement system can be predicted with generalized regression equations. Fitting parameters (R2) in the rage of 0.60 to 0.87 were observed the DRC predictive equations. In addition, verification of those generalized equations was evaluated using different sets of asphalt pavement structures and pavement materials. The differences between calculated and predicted values were found to be within +/-20% for the maximum tensile strain and +/-30% for the maximum compressive strain in the asphalt layer.

  13. PORTLAND CEMENT CONCRETE PAVEMENT FOR FLEXIBLE OVER RIGID COMPOSITE PAVEMENTS (Tollway)

    E-print Network

    .02 of the Standard Specifications except as modified herein. Concrete supplied for the lower layer of an asphalt. If necessary for maintaining intimate contact with the pavement surface, the drag may be weighted using lumber

  14. Concrete Overlay as a Rehabilitation Option for Distressed Asphalt Pavements

    Microsoft Academic Search

    Sudarshan Rajan; J. Olek

    2002-01-01

    Ultra-thin Whitetopping (UTW) involves placing a very thin concrete overlay 50 mm to 100 mm thick (2-4) on the milled surface of a distressed asphalt pavement. To investigate the performance of UTW placed over a flexible pavement subjected to slow and heavy moving wheel loads, whitetopping mixes were placed over a milled pavement surface in the Accelerated Pavement Testing (APT)

  15. CONCRETE REQUIREMENTS FOR ULTRA-THIN CONCRETE OVERLAYS (WHITETOPPING) FOR FLEXIBLE PAVEMENTS

    Microsoft Academic Search

    Jos T. Balbo; Marcos P. Rodolfo

    SUMMARY Whitetopping solutions for old flexible asphalt pavement overlays have been a challange for highway agencies and designers in the recent past years, with special regards to ultra-thin concrete overlays, also called by ultra-thin whitetopping (UTW). Considering the needs of full bond between the UTW and the old asphalt concrete (AC) layer it is clear the impossibility of applying conventional

  16. Improving Rutting Resistance of Pavement Structures Using Geosynthetics: An Overview

    PubMed Central

    Karim, Mohamed Rehan; Khodaii, Ali; Almasi, Mohammad Hadi

    2014-01-01

    A pavement structure consists of several layers for the primary purpose of transmitting and distributing traffic loads to the subgrade. Rutting is one form of pavement distresses that may influence the performance of road pavements. Geosynthetics is one type of synthetic materials utilized for improving the performance of pavements against rutting. Various studies have been conducted on using different geosynthetic materials in pavement structures by different researchers. One of the practices is a reinforcing material in asphalt pavements. This paper intends to present and discuss the discoveries from some of the studies on utilizing geosynthetics in flexible pavements as reinforcement against permanent deformation (rutting). PMID:24526919

  17. Improving rutting resistance of pavement structures using geosynthetics: an overview.

    PubMed

    Mirzapour Mounes, Sina; Karim, Mohamed Rehan; Khodaii, Ali; Almasi, Mohammad Hadi

    2014-01-01

    A pavement structure consists of several layers for the primary purpose of transmitting and distributing traffic loads to the subgrade. Rutting is one form of pavement distresses that may influence the performance of road pavements. Geosynthetics is one type of synthetic materials utilized for improving the performance of pavements against rutting. Various studies have been conducted on using different geosynthetic materials in pavement structures by different researchers. One of the practices is a reinforcing material in asphalt pavements. This paper intends to present and discuss the discoveries from some of the studies on utilizing geosynthetics in flexible pavements as reinforcement against permanent deformation (rutting). PMID:24526919

  18. Layer equivalency factors and deformation characteristics of flexible pavements

    E-print Network

    Hung, Jung-Tsann

    1981-01-01

    Russian Equation THE TEST PROGRAM The Test Site and The Soils Pavement Pressuremeter Test The Dynaflect Test Penetration Test as a Reference The Texas Triaxial Test ANALYSIS OF THE RESULTS The Pressuremeter Tests The Texas Triaxial Test Modulus... Dynaflect Modulus Correlations and Analysis The Equivalency Factors Page 12 16 23 31 31 31 48 48 51 52 52 67 74 86 TABLE OF CONTENTS (Continued) New Standard Procedure for Cyclic Pressuremeter Test PROCEDURE FOR DETERMINING...

  19. A Bayesian approach for improved pavement performance prediction

    Microsoft Academic Search

    Eun Sug Park; Roger E. Smith; Thomas J. Freeman; Clifford H. Spiegelman

    2008-01-01

    We present a method for predicting future pavement distresses such as longitudinal cracking. These predicted distress values are used to plan road repairs. Large inherent variability in measured cracking and an extremely small number of observations are the nature of the pavement cracking data, which calls for a parametric Bayesian approach. We model theoretical pavement distress with a sigmoidal equation

  20. Rebound and residual in situ pavement displacements measured during NAPTF performance testing

    Microsoft Academic Search

    Kasthurirangan Gopalakrishnan; Marshall R. Thompson

    2007-01-01

    The FAA's National Airport Pavement Test Facility (NAPTF) was constructed to generate full-scale test data needed for the development of advanced airport pavement design procedures. In this paper, the comparative effects of six-wheel Boeing 777 (B777) and four-wheel Boeing 747 (B747) simulated landing gear loading on the multi-depth deflectometer (MDD) responses of two NAPTF low-strength subgrade flexible test sections are

  1. A study of certain elastic and plastic strains induced in flexible pavement systems by repetitive wheel loads

    E-print Network

    Meyer, Kirby Thomas

    1959-01-01

    L)NRARY 1 4 N COLLSQE OF TEXAS A STUDY OF CERTAIN ELASTIC AND PLASTIC STRAINS INDUCED IN FLEXIBLE PAVEMENT SYSTEMS BT REPETITIVE NHEEL LOADS A Thesis By KISSY T. lPTER Submitted to the Graduate School of the Agricultural and Mechanical... College of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE January, 1959 Major Subject: Civil Engineering A STUDY OF CERTAIN ELASTIC AND PLASTIC STRAINS INDUCED IN FLEXIBLE PAVENENT SYSTENS BY REPETITIVE MEREL...

  2. The falling weight deflectometer (FWD) test is one of the most com-monly used tools for nondestructive evaluation of flexible pavements.

    E-print Network

    Guzina, Bojan

    for nondestructive evaluation of flexible pavements. Although the test is intrinsically dynamic, the stateThe falling weight deflectometer (FWD) test is one of the most com- monly used tools in estimation of the pavement's stiffness characteristics. Because of the decided dynamic nature of the FWD test

  3. Discussion on the Prediction Method of the Pavement Performance for Expressway

    Microsoft Academic Search

    He Xiao-ming; Guan Peng; Hu Guo-xiang; Zhou Lin

    2009-01-01

    The empirical regression model was selected for forecasting the preventive maintenance time; the grey system theory was used to determine if pavements were fit for preventive maintenance. Combined with the instance, on the forecasting of the pavement performance for an expressway, the application of the grey system theory was introduced.

  4. The development of correlations between HMA pavement performance and aggregate shape properties

    E-print Network

    McGahan, Jeremy

    2006-04-12

    The physical characteristics of aggregates (form, angularity, and texture) are known to affect the performance of hot mix asphalt (HMA) pavements. Efforts to develop relationships between these aggregate characteristics and aggregate performance...

  5. AN AUTONOMOUS ROBOT EQUIPPED WITH THE GPS VIRTUAL REFERENCE STATION (VRS) SYSTEM TO PERFORM PAVEMENT DISTRESS SURVEYS

    Microsoft Academic Search

    Jia-Ruey Chang; Shih-Chung Kang

    Various pavement distresses (cracking, pothole, manhole, patching, etc.) that exist randomly across pavements deteriorate the quality of the pavement structure and need to be immediately dealt using proper maintenance and rehabilitation (M&R) strategies. Traditionally pavement distress surveys are performed using manually operated or driven equipment, and hence are very labour-intensive, time-consuming and lack intelligent detection methods. In this study, an

  6. Performance-Based Concrete Pavement Mix Design System Performance-Based Design Guide for New and Rehabilitated

    E-print Network

    Strategic Research Plan #12;· Performance-Based Concrete Pavement Mix Design System · Performance-Based Design Guide for New and Rehabilitated Concrete Pavements · High-Speed Nondestructive Testing and Intelligent Construction Systems · Optimized Surface Characteristics for Safe, Quiet, and Smooth Concrete

  7. Flexible sigmoidoscopy performed by nurses.

    PubMed

    Goodfellow, P B

    2006-06-01

    Flexible sigmoidoscopy by nurses has rapidly become a widely accepted technique for distal colonic investigation. This review explores the issues of training and application of nurse performed flexible sigmoidoscopy, including the limitations, complications and cost issues. PMID:16586240

  8. Identification of asphalt binder properties that affect cracking performance of hot mixed asphalt concrete pavements

    E-print Network

    Hastings, Charles Patrick

    1997-01-01

    fulfillment of the requirements for the degree of MASTER OF SCIENCE May l997 Major Subject. Civil Engineering IDENTIFICATION OF ASPHALT BINDER PROPERTIES THAT AFFECT CRACKING PERFORMANCE OF HOT MIXED ASPHALT CONCRETE PAVEMENTS A Thesis by CHARLES.... Bradley (Member) Ignacio Rodri ez turbe (Head of Department) May 1997 Major Subject: Civil Engineering ABSTRACT Identification of Asphalt Binder Properties That Affect Cracking Performance of Hot Mixed Asphalt Concrete Pavements. (May 1997...

  9. A relation of measured deflections, pavement performance and soil characteristics

    E-print Network

    Hanna, Daniel Nelson

    1957-01-01

    moving wheel loads. At the test road sponsored by the "&iestern Association of State Highway Officials in Idaho?i?+ pavement defleotions were studied under ocntrolled traffio oonditions ~ A similar study was made in Virginia on a newly oonstruoted... test road, In California? pavement defleotions were measured on mcvs 4 ments that hsd beer, in ssrvioe for several years ~ Upon observation of the results of these studies ~ whish inoluded a remarkable nor relation between road deflection and road...

  10. Relating tensile, bending, and shear test data of asphalt binders to pavement performance

    SciTech Connect

    Chen, J.S.; Tsai, C.J. [National Cheng-Kung Univ., Tainan (Taiwan, Province of China). Dept. of Civil Engineering] [National Cheng-Kung Univ., Tainan (Taiwan, Province of China). Dept. of Civil Engineering

    1998-12-01

    Eight different asphalt binders representing a wide range of applications for pavement construction were tested in uniaxial tension, bending, and shear stresses. Theoretical analyses were performed in this study to covert the data from the three engineering tests to stiffness moduli for predicting pavement performance. At low temperatures, high asphalt stiffness may induce pavement thermal cracking; thus, the allowable maximum stiffness was set at 1,000 MPa. At high temperatures, low asphalt stiffness may lead to pavement rutting (ruts in the road); master curves were constructed to rank the potential for rutting in the asphalts. All three viscoelastic functions were shown to be interchangeable within the linear viscoelastic region. When subjected to large deformation in the direct tension test, asphalt binders behaved nonlinear viscoelastic in which the data under bending, shear and tension modes were not comparable. The asphalts were, however, found toe exhibit linear viscoelasticity up to the failure point in the steady-state strain region.

  11. Probabilistic Numerical Simulation of Pavement Performance using MEPDG

    Microsoft Academic Search

    Steven F. Wojtkiewicz; Lev Khazanovich; Gaurav Gaurav; Raul Velasquez

    2010-01-01

    It is widely acknowledged that the accurate simulation of complex engineering systems, such as nuclear power reactors, modern weapon systems, and aircraft, requires probabilistic analysis due to inherent uncertainties in their models' parameters. The demand for and the complexity of probabilistic analysis prompted Sandia National Laboratories to develop a versatile software toolkit, DAKOTA, adaptable to various engineering applications. Pavements are

  12. Monitoring pavement response and performance using in-situ instrumentation

    SciTech Connect

    Chen, D.H.; Bilyeu, J.; Hugo, F.

    1999-07-01

    The purpose of this paper is to present the effectiveness of in-situ instrumentation on diagnosing the pavement layer conditions under full-scale accelerated traffic loading. The test section is an in-service pavement (US281) in Jacksboro, Texas. Multi-Depth Deflectometers (MDDs) are used to measure both permanent deformations and transient deflections, caused by accelerated traffic loading and Falling Weight Deflectometers (MDDs) are used to measure both permanent deformations and transient deflections, caused by accelerated traffic loading and Falling Weight Deflectometer (FWD) tests. Four different FWD loads of 25, 40, 52, and 67 kN were applied in close proximity to the MDDs at various traffic loading intervals to determine pavement conditions. It was found that the majority of rutting occurred in the newly recycled asphalt mix. The aged ({gt}40 years) underlying base and subgrade layers contributed less than 30% to overall rutting. Only the top recycled Asphalt layer underwent notable deterioration due to traffic loading. Up to 1.5 million axle repetitions, the test pad responded to FWD load almost linearly, not only over the whole pavement system but also within individual layers. However, under higher FWD loads, the percentage of total deflection contributed by the subgrade increased.

  13. Asphalt Mechanics, a Key Tool for Improved Pavement Performance Predictions

    Microsoft Academic Search

    A. A. A. Molenaar

    Pavement design has relied for a very long time on simplified mechanistic methods and experience. The need for long life maintenance\\u000a structures, the use of new, costly, materials with enhanced characteristics, the need to spend the maintenance euro as effective\\u000a as possible, the need to quantify risks etc, have given a boost to a renewed interest in the characterization and

  14. Water Quality Performance of Three Side-by-Side Permeable Pavement Surface Materials: Three Year Update

    EPA Science Inventory

    Communities are increasingly installing structural low impact development (LID) practices to mange stormwater and reduce pollutant loads associated with stormwater runoff. Permeable pavement is a LID practice that has limited research on working-scale, side-by-side performance o...

  15. PAVEMENT PREDICTION PERFORMANCE MODELS AND RELATION WITH TRAFFIC FATALITIES AND INJURIES

    E-print Network

    Boyer, Edmond

    PAVEMENT PREDICTION PERFORMANCE MODELS AND RELATION WITH TRAFFIC FATALITIES AND INJURIES V. CEREZO/Sideway force Coefficient Routine Investigation Machine), macrotexture values (Mean Profile Depth), traffic data part, the texture data were compared to accidents data in view of finding a relation between them

  16. LONG-TERM IN-SITU INFILTRATION PERFORMANCE OF PERMEABLE CONCRETE BLOCK PAVEMENT

    Microsoft Academic Search

    Soenke Borgwardt

    SUMMARY Since it is a design criteria for road drainage and sewer systems, the infiltration performance of permeable concrete block pavement (CBP) is of important significance during the service life of a road construction. Due to the entrainment of mineral and organic fines into the pores of porous concrete blocks or into the aggregates used in joints or openings, the

  17. Flexural fatigue performance of concrete containing nano-particles for pavement

    Microsoft Academic Search

    Hui Li; Mao-hua Zhang; Jin-ping Ou

    2007-01-01

    The flexural fatigue performance of concrete containing nano-particles for pavement is experimentally studied. Both nano-TiO2 and nano-SiO2 are respectively employed to be as the additives. For comparison, the flexural fatigue performance of plain concrete and the concrete containing polypropylene (PP) fibers is also experimentally studied in this article. The test results indicate that the fatigue lives of concretes containing nano-particles

  18. General outlook of pavement and vehicle dynamics

    SciTech Connect

    Mamlouk, M.S. [Arizona State Univ., Tempe, AZ (United States). Dept. of Civil and Environmental Engineering

    1997-11-01

    The interaction between vehicle and pavement is complex since pavement roughness excites the dynamic forces generated by vehicles, while these dynamic forces simultaneously increase the pavement roughness. The objective of this paper is to provide an overview of the results of recent research related to pavement and vehicle dynamics and their interaction and to evaluate their potential use in the design and management of pavements. Pavement dynamic models are capable of determining stresses, strains, and deflections in various directions when harmonic, pulse, or transient loads are applied. Vehicle dynamic models simulate the effect of pavement roughness on the inertia of various vehicle components. These models can predict the dynamic forces produced by different axles and wheels of traveling vehicles at different locations along the pavement. Pavement response computed using dynamic models matches field measurements closer than those computed using static models. The concept of vehicle-pavement interaction can be applied to weigh-in-motion, pavement design and performance, and vehicle regulations.

  19. Evaluation of the existing performance models used for pavement management by the Texas Department of Transportation

    E-print Network

    Mukherjee, Biswajit

    1998-01-01

    Development of Performance Models Considerations Types of Models Data Analysis Empirical Models . Regression Models Survivor Curves Markov Models Semi-Markov Models nl v VI V11 X1 Xlv 4 5 7 7 8 10 11 11 13 13 14 15 16 18 19... 174 175 175 177 177 179 180 182 183 185 186 188 LIST OF FIGURES Figure Page 1 Typical Regression Curves 2 A Typical Survivor Curve . . 3 Difference between Markov and Semi-Markov Models . . 4 Definition of Thick Pavement by Classical...

  20. Water quality and quantity assessment of pervious pavements performance in experimental car park areas.

    PubMed

    Saudo-Fontaneda, Luis A; Charlesworth, Susanne M; Castro-Fresno, Daniel; Andres-Valeri, Valerio C A; Rodriguez-Hernandez, Jorge

    2014-01-01

    Pervious pavements have become one of the most used sustainable urban drainage system (SUDS) techniques in car parks. This research paper presents the results of monitoring water quality from several experimental car park areas designed and constructed in Spain with bays made of interlocking concrete block pavement, porous asphalt, polymer-modified porous concrete and reinforced grass with plastic and concrete cells. Moreover, two different sub-base materials were used (limestone aggregates and basic oxygen furnace slag). This study therefore encompasses the majority of the materials used as permeable surfaces and sub-base layers all over the world. Effluent from the test bays was monitored for dissolved oxygen, pH, electric conductivity, total suspended solids, turbidity and total petroleum hydrocarbons in order to analyze the behaviour shown by each combination of surface and sub-base materials. In addition, permeability tests were undertaken in all car parks using the 'Laboratorio Caminos Santander' permeameter and the Cantabrian Portable Infiltrometer. All results are presented together with the influence of surface and sub-base materials on water quality indicators using bivariate correlation statistical analysis at a confidence level of 95%. The polymer-modified porous concrete surface course in combination with limestone aggregate sub-base presented the best performance. PMID:24718346

  1. Review of the development of concrete pavement surface types and their acoustic performance with time

    NASA Astrophysics Data System (ADS)

    Scofield, Larry A.

    2005-09-01

    Roadways have been constructed out of concrete pavements in the United States since the late 1800s. Numerous surface textures have been produced including burlap drag, astroturf, uniformly and random transverse tined, longitudinally tined, and both profile and whisper diamond grinding processes. Each surface evolved for specific reasons during the historical development of Portland Cement Concrete Pavements (PCCP).This paper reviews the development of these various surface texture types and the reasons for their evolution. In addition, results from both far field and near field acoustic testing are presented to evaluate the ``acoustic'' performance of these surfaces over time.For five surface types, 1/24 octave analysis were conducted on CPX data obtained with a single tire. The spectrum of each of these surface types is presented for comparison. For three of the surfaces, speed gradient testing, ranging between 25-75 MPH was conducted. 1/24 octave analysis of each of these runs was conducted so that that any speed induced spectrum shifts could be observed.The results to date indicate that the adverse tonal properties of some PCCP surfaces can be eliminated through diamond grinding and prevented by not constructing transverse tined PCCP.

  2. Binzhou Perpetual Pavement Test Road

    Microsoft Academic Search

    Yongshun Yang; Jincheng Wei; Wang Lin; David Timm; Gerald Huber

    2009-01-01

    Expressway construction has been carried out on a large-scale in China. Vigorous economical development has caused rapid growth in traffic volume and truck axle loads creating a severe challenge for the pavement structure design. Therefore, the high-performance and low- maintenance cost of a long-life perpetual pavement structure is gaining attention. This paper discusses the first perpetual asphalt pavement test road

  3. Generating enhanced site topography data to improve permeable pavement performance assessment methods - presentation

    EPA Science Inventory

    Permeable pavement surfaces are infiltration based stormwater control measures (SCM) commonly applied in parking lots to decrease impervious area and reduce runoff volume. Many are not optimally designed however, as little attention is given to draining a large enough contributin...

  4. A Methodology for Developing Performance-Related Specifications for Pavement Preservation Treatments

    E-print Network

    Liu, Litao

    2013-09-23

    , the current literature lacks a methodology for developing PRS for pavement preservation treatments. The aim of this research is to fill this gap in the literature, with focus on thin HMA overlays. In this dissertation, a novel approach was devised...

  5. Life-Cycle Assessment of Highway Pavement Alternatives in Aspects of Economic, Environmental, and Social Performance

    E-print Network

    Mao, Zhuting

    2012-10-19

    , hazardous waste, toxic releases, water withdrawals, and transportation movements. The analysis results indicate that CRCP be the most cost-efficient and sustainable choice among the selected rigid pavement alternatives as it requires the lowest life...

  6. Evaluation of Performance and Design of Ultra-Thin Whitetopping (Bonded Concrete Resurfacing) Using Large-Scale Accelerated Pavement Testing

    Microsoft Academic Search

    Scott Newbolds; Jan Olek

    2008-01-01

    Ultra-Thin Whitetopping (UTW) is a pavement rehabilitation technique that involves the placement of a thin Portland Cement Concrete (PCC) overlay, 2 inches (50 mm) to 4 inches (100 mm) thick, over a distressed Hot Mix Asphalt (HMA) pavement. Typically, the HMA pavement is milled and cleaned which helps to create a bond between the existing HMA pavement and the PCC

  7. Evaluation of performance and design of Ultra-Thin Whitetopping (bonded concrete resurfacing) using large-scale accelerated pavement testing

    Microsoft Academic Search

    Scott Andrew Newbolds

    2007-01-01

    Ultra-Thin Whitetopping (UTW) is a pavement rehabilitation technique that involves the placement of a thin Portland Cement Concrete (PCC) overlay, 2 inches (50 mm) to 4 inches (100 mm) thick, over a distressed Hot Mix Asphalt (HMA) pavement. Typically, the HMA pavement is milled and cleaned which helps to create a bond between the existing HMA pavement and the PCC

  8. Bridge and pavement maintenance

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, M. W.; Law, D. A.; Dixon, W. C.; Elkins, G. E.; Mucullough, B. F.; Darter, M. I.; Yoder, E. J.; Florence, R. H., Jr.; Virkler, S. J.; McGhee, K. H.

    1981-03-01

    Deterioration of New York State Highway structures; precast repair of continuously reinforced concrete pavement (abridgment) patching of continuously reinforced concrete pavements, evaluation of several maintenance methods for continuously reinforced concrete pavement, patching jointed concrete pavements, highway pavement repairs by using polymer concrete, pressure grouting of concrete pavements, and choosing cost-effective maintenance are discussed.

  9. Permeable Pavement

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    Students investigate how different riparian ground covers, such as grass or pavement, affect river flooding. They learn about permeable and impermeable materials through the measurement how much water is absorbed by several different household materials in a model river. Students use what they learn to make recommendations for engineers developing permeable pavement. Also, they consider several different limitations for design in the context of a small community.

  10. Experimental pavement delineation treatments

    NASA Astrophysics Data System (ADS)

    Bryden, J. E.; Lorini, R. A.

    1981-06-01

    Visibility and durability of materials used to delineate shoulders and medians adjacent to asphalt pavements were evaluated. Materials evaluated were polysulfide and coal tar epoxies, one and two component polyesters, portland cement, acrylic paints, modified-alkyd traffic paint, preformed plastic tape, and thermoplastic markings. Neat applications, sand mortars, and surface treatments were installed in several geometric patterns including cross hatches, solid median treatments, and various widths of edge lines. Thermoplastic pavement markings generally performed very well, providing good visibility under adverse viewing conditions for at least 4 years. Thermoplastic 4 in. wide edge lines appear to provide adequate visibility for most conditions.

  11. Rutting and drainage design methodology for a concrete block pavement

    E-print Network

    Poduska, Daryl Jason

    1998-01-01

    procedure provides a measure of the pavement's performance by predicting the amount of rutting. This thesis also presents the analysis of the structural performance of a concrete block pavement that was constructed at Texas A&M's Riverside campus...

  12. Effects of Using Silica Fume and Polycarboxylate-Type Superplasticizer on Physical Properties of Cementitious Grout Mixtures for Semiflexible Pavement Surfacing

    PubMed Central

    Karim, Mohamed Rehan; Mahmud, Hilmi; Mashaan, Nuha S.; Katman, Herdayati; Husain, Nadiah Md

    2014-01-01

    Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout. PMID:24526911

  13. Effects of using silica fume and polycarboxylate-type superplasticizer on physical properties of cementitious grout mixtures for semiflexible pavement surfacing.

    PubMed

    Koting, Suhana; Karim, Mohamed Rehan; Mahmud, Hilmi; Mashaan, Nuha S; Ibrahim, Mohd Rasdan; Katman, Herdayati; Husain, Nadiah Md

    2014-01-01

    Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout. PMID:24526911

  14. Performance of an enhanced pervious pavement system loaded with large volumes of hydrocarbons.

    PubMed

    Newman, Alan P; Puehmeier, Tim; Shuttleworth, Andy; Pratt, Christopher J

    2014-01-01

    Five litres of lubricating oil and two 8.5 litre batches of diesel were deposited on each of two hydraulically isolated experimental enhanced pervious pavement parking bays. The 50 mm aggregate subbases of the two bays were of either recycled concrete or crushed limestone. The bays were constructed in such a way that a near-surface gravity separator was created by the arranging of the outlet pipes such that a permanent pool of water was maintained in the system and water could only enter from below the level of any floating oil. Dissolved/dispersed hydrocarbons were measured at acceptable concentrations when monitoring was carried out over a period of approximately 5 months. The maximum concentration was 7.2 mg/l and of all the samples collected only 3% exceeded the 5 mg/l limit applied in the UK for a class 1 interceptor, and the majority of samples had hydrocarbon concentrations of less than 2 mg/l. Much more significant is the fact that no free product was discharged from either system up to the time the experiment was dismantled 2 years from the first oil application despite the fact that sufficient hydrocarbon had been added to each pavement to produce a film on a water surface of over 500 hectares. PMID:25225930

  15. PARTIAL-DEPTH REPAIR OF CONCRETE PAVEMENTSCONCRETE PAVEMENTS

    E-print Network

    April 2012 PARTIAL-DEPTH REPAIR OF CONCRETE PAVEMENTSCONCRETE PAVEMENTS GUIDE FOR #12;#12;Guide for Partial-Depth Repair of Concrete Pavements i Technical Report Documentation Page 1. Report No. 2 Depth Repair of Concrete Pavements April 2012 6. Performing Organization Code 7. Author(s) 8. Performing

  16. LRRB Pavement Management Systems Pavement Management Systems

    E-print Network

    Minnesota, University of

    LRRB Pavement Management Systems Pavement Management Systems Presented by: Michael Marti SRF devoted to local road research Research is: Managed by the LRRB Conducted by DOT, U of M, Mn for implementing and monitoring research results (RIC) #12;LRRB Pavement Management Systems LRRB Structure LRRB

  17. High-Performance Flexible Waveguiding Photovoltaics

    PubMed Central

    Chou, Chun-Hsien; Chuang, Jui-Kang; Chen, Fang-Chung

    2013-01-01

    The use of flat-plane solar concentrators is an effective approach toward collecting sunlight economically and without sun trackers. The optical concentrators are, however, usually made of rigid glass or plastics having limited flexibility, potentially restricting their applicability. In this communication, we describe flexible waveguiding photovoltaics (FWPVs) that exhibit high optical efficiencies and great mechanical flexibility. We constructed these FWPVs by integrating poly-Si solar cells, a soft polydimethylsiloxane (PDMS) waveguide, and a TiO2-doped backside reflector. Optical microstructures that increase the light harvesting ability of the FWPVs can be fabricated readily, through soft lithography, on the top surface of the PDMS waveguide. Our optimized structure displayed an optical efficiency of greater than 42% and a certified power conversion efficiency (PCE) of 5.57%, with a projected PCE as high as approximately 18%. This approach might open new avenues for the harvesting of solar energy at low cost with efficient, mechanically flexible photovoltaics. PMID:23873225

  18. Evaluation of tire pressure, tire construction, axle configuration, and axle load on flexible pavement performance

    E-print Network

    Jamy, Ahmad Najeeb

    1991-01-01

    (aa) (8) where, e, -aJE WC = -water content (I) a, - deviator stress (psi), and E = resilient modulus of limerock base material (psi) Subgrade Permanent deformation data on fine grained soils consisting primarily of clayey silts and silty clays...

  19. Simulated aircraft load testing and non-destructive evaluation of bituminous pavements

    Microsoft Academic Search

    Kasthurirangan Gopalakrishnan; Marshall R. Thompson

    2008-01-01

    The US Federal Aviation Administration's National Airport Pavement Test Facility was constructed to generate full-scale accelerated pavement test data for the development of advanced airport pavement design criteria. During the first round of traffic testing, a six-wheel (Boeing 777) landing gear and a four-wheel (Boeing 747) landing gear were trafficked on flexible test pavements until they were deemed failed. Non-destructive

  20. Quantity Flexibility Contracts and Supply Chain Performance

    Microsoft Academic Search

    A. A. Tsay; W. S. Lovejoy

    1999-01-01

    The Quantity Flexibility (QF) contract is a method for coordinating materials and information flows in supply chains operating under rolling-horizon planning. It stipulates a maximum percentage revision each element of the period-by-period replenishment schedule is allowed per planning iteration. The supplier is obligated to cover any requests that remain within the upside limits. The bounds on reductions are a form

  1. Flexibility and its effects on sports injury and performance.

    PubMed

    Gleim, G W; McHugh, M P

    1997-11-01

    Flexibility measures can be static [end of ROM (range of motion)], dynamic-passive (stiffness/compliance) or dynamic-active (muscle contracted, stiffness/compliance). Dynamic measures of flexibility are less dependent on patient discomfort and are more objective. Acute and chronic changes in flexibility are likely to occur with stretching exercises, but it is difficult to distinguish between changes in stretch tolerance as opposed to changes in muscle stiffness. How flexibility is measured impacts these findings. There is no scientifically based prescription for flexibility training and no conclusive statements can be made about the relationship of flexibility to athletic injury. The literature reports opposing findings from different samples, frequently does not distinguish between strain, sprain and overuse injury, and rarely uses the proper denominator of exposure. There is basic scientific evidence to suggest that active warm-up may be protective against muscle strain injury but clinical research is equivocal on this point. Typically, specific flexibility patterns are associated with specific sports and even positions within sports. The relationship of flexibility to athletic performance is likely to be sport-dependent. Decreased flexibility has been associated with increased in-line running and walking economy. Increased stiffness may be associated with increased isometric and concentric force generation, and muscle energy storage may be best manifested by closely matching muscle stiffness to the frequency of movement in stretch-shorten type contractions. PMID:9368275

  2. A Study on the Estimation of the Performance of Sediment Pavement and the Required Function of the Farm Road in a Paddy Area

    NASA Astrophysics Data System (ADS)

    Ogata, Hidehiko; Noda, Tomoyuki; Sakamoto, Yasufumi; Shinotsuka, Masanori; Kamada, Osamu; Nakamura, Kazuaki

    The pavement rate of the farm road which becomes important in activities of agricultural production, circulation of agricultural products and rural life is low. There are many farm roads to which the function of traveling performance, traveling comfort and prevention of the damage of agricultural products in transportation is not secured. Maintenance including improvement in the pavement rate of a farm road must be economically carried out based on the service environment, the circumference environment and the required function according to the kind of farm road. In this research, the problem of the farm road in a paddy area was extracted from the questionnaire to a land improvement district as an administrator, and the conditions which should be taken into consideration in maintenance of a farm road were clarified. The problem of a farm road is deformation of a road surface and a request is a period which does not need to repair. Moreover, the present performance of ground property and road surface of sediment pavement on-farm road was evaluated. Positive correlation is between the standard deviation of modulus of elasticity of the soil and surface roughness, negative correlation is between the modulus of elasticity of the soil in the rut and rutting depth.

  3. Flexible nanoscale high-performance FinFETs.

    PubMed

    Torres Sevilla, Galo A; Ghoneim, Mohamed T; Fahad, Hossain; Rojas, Jhonathan P; Hussain, Aftab M; Hussain, Muhammad Mustafa

    2014-10-28

    With the emergence of the Internet of Things (IoT), flexible high-performance nanoscale electronics are more desired. At the moment, FinFET is the most advanced transistor architecture used in the state-of-the-art microprocessors. Therefore, we show a soft-etch based substrate thinning process to transform silicon-on-insulator (SOI) based nanoscale FinFET into flexible FinFET and then conduct comprehensive electrical characterization under various bending conditions to understand its electrical performance. Our study shows that back-etch based substrate thinning process is gentler than traditional abrasive back-grinding process; it can attain ultraflexibility and the electrical characteristics of the flexible nanoscale FinFET show no performance degradation compared to its rigid bulk counterpart indicating its readiness to be used for flexible high-performance electronics. PMID:25185112

  4. Development and implementation of an enhanced procedure for estimating pavement rehabilitation and maintenance expenditures

    E-print Network

    Garcia-Diaz, Juan Carlos

    1987-01-01

    with critical values of performance. 3. Calculation of Survival Parameters. The time elapsed until a new pavement section needs a major rehabilitation is known as the service life of the pavement. The statistical distribution of the service life is referred... specified time. The time elapsed until a new pavement section needs a major rehabilitation, or the time between major rehabilitations for an existing pavement section, is known as the service life of the pavement. The statistical distribution...

  5. Utilize Cementitious High Carbon Fly Ash (CHCFA) to Stabilize Cold In-Place Recycled (CIR) Asphalt Pavement as Base Coarse

    SciTech Connect

    Wen, Haifang; Li, Xiaojun; Edil, Tuncer; O'Donnell, Jonathan; Danda, Swapna

    2011-02-05

    The purpose of this study was to evaluate the performance of cementitious high carbon fly ash (CHCFA) stabilized recycled asphalt pavement as a base course material in a real world setting. Three test road cells were built at MnROAD facility in Minnesota. These cells have the same asphalt surface layers, subbases, and subgrades, but three different base courses: conventional crushed aggregates, untreated recycled pavement materials (RPM), and CHCFA stabilized RPM materials. During and after the construction of the three cells, laboratory and field tests were carried out to characterize the material properties. The test results were used in the mechanistic-empirical pavement design guide (MEPDG) to predict the pavement performance. Based on the performance prediction, the life cycle analyses of cost, energy consumption, and greenhouse gasses were performed. The leaching impacts of these three types of base materials were compared. The laboratory and field tests showed that fly ash stabilized RPM had higher modulus than crushed aggregate and RPM did. Based on the MEPDG performance prediction, the service life of the Cell 79 containing fly ash stabilized RPM, is 23.5 years, which is about twice the service life (11 years) of the Cell 77 with RPM base, and about three times the service life (7.5 years) of the Cell 78 with crushed aggregate base. The life cycle analysis indicated that the usage of the fly ash stabilized RPM as the base of the flexible pavement can significantly reduce the life cycle cost, the energy consumption, the greenhouse gases emission. Concentrations of many trace elements, particularly those with relatively low water quality standards, diminish over time as water flows through the pavement profile. For many elements, concentrations below US water drinking water quality standards are attained at the bottom of the pavement profile within 2-4 pore volumes of flow.

  6. Application Performance and Flexibility on Exokernel Systems

    Microsoft Academic Search

    M. Frans Kaashoek; Dawson R. Engler; Gregory R. Ganger; Hctor M. Briceo; Russell Hunt; David Mazires; Thomas Pinckney; Robert Grimm; John Jannotti; Kenneth Mackenzie

    1997-01-01

    The exokernel operating system architecture safely gives untrusted software efficient control over hardware and software resources by separating management from protection. This paper describes an exokernel system that allows specialized applications to achieve high performance without sacrificing the performance of unmod- ified UNIX programs. It evaluates the exokernel architecture by measuring end-to-end application performance on Xok, an exo- kernel for

  7. Performance of a wing with nonuniform flexibility in hovering flight

    NASA Astrophysics Data System (ADS)

    Shoele, Kourosh; Zhu, Qiang

    2013-04-01

    The deformability of insect wings is associated with the embedded skeleton (venation). In this paper, the aerodynamic performance of wings with nonuniform flexibility is computationally investigated. By using a two-dimensional rendition, the underlying veins are modeled as springs, and the membrane is modeled as a flexible plate. The focus is on the effects of the detailed distribution of vein flexibility upon the performance of such a wing in the generation of lift force. Specifically, we are interested in finding the importance of leading edge strengthening. Towards this end, the aerodynamic performances of three wings, a rigid wing, a flexible wing with identical veins, and a flexible wing with strengthened leading edge, are studied and compared against each other. It is shown that the flexible wing with leading edge strengthening is capable of producing significantly higher lift force without consuming more energy. This is found to be related to the stabilizing and cambering effects at the leading edge, which enhances the leading edge vortices. In addition, in contrast to the other two wings, which show sensitivity to kinematic parameters, the wing with strengthened leading edge perform well over a wide range of parameters.

  8. 4/28/2010 1Porous Pavements Porous Pavements

    E-print Network

    Minnesota, University of

    4/28/2010 1Porous Pavements Porous Pavements for Stormwater Restoration in Urban Environments Cliff Aichinger Ramsey-Washington Metro Watershed District #12;4/28/2010 2Porous Pavements Porous Pavements Why am new volume reduction rules. Porous pavement is one of a relative few BMPs that address stormwater

  9. Hydrologic and Pollutant Removal Performance of a Full-Scale, Fully Functional Permeable Pavement Parking Lot - paper

    EPA Science Inventory

    To meet the need for long-term, full-scale, replicated studies of permeable pavement systems used in their intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage conditions, and maintenance regimes to evaluate these systems, the EPA?s Urb...

  10. Semiconducor wires and ribbons for high performance flexible electronics

    Microsoft Academic Search

    Y. Sun; A. J. Baca; J.-H. Ahn; E. Menard; H.-S Kim; W. Choi; D.-H Kim; Y. Huang

    2008-01-01

    This article reviews the properties, fabrication and assembly of inorganic semiconductor materials that can be used as active building blocks to form high-performance transistors and circuits for flexible and bendable large-area electronics. Obtaining high performance on low temperature polymeric substrates represents a technical challenge for macroelectronics. Therefore, the fabrication of high quality inorganic materials in the form of wires, ribbons,

  11. Flexibility.

    ERIC Educational Resources Information Center

    Humphrey, L. Dennis

    1981-01-01

    Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

  12. Flexibility of movement organization in piano performance.

    PubMed

    Furuya, Shinichi; Altenmller, Eckart

    2013-01-01

    Piano performance involves a large repertoire of highly skilled movements. The acquisition of these exceptional skills despite innate neural and biomechanical constraints requires a sophisticated interaction between plasticity of the neural system and organization of a redundant number of degrees of freedom (DOF) in the motor system. Neuroplasticity subserving virtuosity of pianists has been documented in neuroimaging studies investigating effects of long-term piano training on structure and function of the cortical and subcortical regions. By contrast, recent behavioral studies have advanced the understanding of neuromuscular strategies and biomechanical principles behind the movement organization that enables skilled piano performance. Here we review the motor control and biomechanics literature, introducing the importance of describing motor behaviors not only for understanding mechanisms responsible for skillful motor actions in piano playing, but also for advancing diagnosis and rehabilitation of movement disorders caused by extensive piano practice. PMID:23882199

  13. Flexibility of movement organization in piano performance

    PubMed Central

    Furuya, Shinichi; Altenmller, Eckart

    2013-01-01

    Piano performance involves a large repertoire of highly skilled movements. The acquisition of these exceptional skills despite innate neural and biomechanical constraints requires a sophisticated interaction between plasticity of the neural system and organization of a redundant number of degrees of freedom (DOF) in the motor system. Neuroplasticity subserving virtuosity of pianists has been documented in neuroimaging studies investigating effects of long-term piano training on structure and function of the cortical and subcortical regions. By contrast, recent behavioral studies have advanced the understanding of neuromuscular strategies and biomechanical principles behind the movement organization that enables skilled piano performance. Here we review the motor control and biomechanics literature, introducing the importance of describing motor behaviors not only for understanding mechanisms responsible for skillful motor actions in piano playing, but also for advancing diagnosis and rehabilitation of movement disorders caused by extensive piano practice. PMID:23882199

  14. An Asset Management Framework Based on Field Performance of Pavement Markings

    E-print Network

    Madiri, Sam

    2011-08-08

    . Sectional assessment and management methods were proposed as a part of a practical restriping methodology. An information tool was developed in a geographic information system (GIS) environment as an application. Retroreflectivity was the only performance...

  15. STATUS OF POROUS PAVEMENT RESEARCH

    EPA Science Inventory

    This paper discusses the U.S. Environmental Protection Agency's porous pavement research program along with the economics, advantages, potential applications, and status and future research needs of porous pavements. Porous pavements are an available stormwater management techniq...

  16. A methodological framework for modeling pavement maintenance costs for projects with performance-based contracts

    Microsoft Academic Search

    Kamalesh Panthi

    2009-01-01

    Performance-based maintenance contracts differ significantly from material and method-based contracts that have been traditionally used to maintain roads. Road agencies around the world have moved towards a performance-based contract approach because it offers several advantages like cost saving, better budgeting certainty, better customer satisfaction with better road services and conditions. Payments for the maintenance of road are explicitly linked to

  17. A Methodological Framework for Modeling Pavement Maintenance Costs for Projects with Performance-based Contracts

    Microsoft Academic Search

    Kamalesh Panthi

    2009-01-01

    Performance-based maintenance contracts differ significantly from material and method-based contracts that have been traditionally used to maintain roads. Road agencies around the world have moved towards a performance-based contract approach because it offers several advantages like cost saving, better budgeting certainty, better customer satisfaction with better road services and conditions. Payments for the maintenance of road are explicitly linked to

  18. Effects of structure flexibility on horizontal axis wind turbine performances

    NASA Astrophysics Data System (ADS)

    Coiro, D. P.; Daniele, E.; Scherillo, F.

    2013-10-01

    This work illustrates the effects of flexibility of rotor blades and turbine tower on the performances of an horizontal axis wind turbine (HAWT) designed by our ADAG research group, by means of several example applied on a recent project for a active pitch controlled upwind 60 kW HAWT. The influence of structural flexibility for blade only, tower only and blade coupled with tower configuration is investigated using an aero-elastic computer-aided engineering (CAE) tool for horizontal axis wind turbines named FAST developed at National Renewable Energy Laboratory (NREL) of USA. For unsteady inflow conditions in front of the isolated HAWT the performances in rigid and flexible operation mode are computed and compared in order to illustrate the limitation included within a classical rigid body approach to wind turbine simulation.

  19. Price flexibility and market performance in experimental markets

    Microsoft Academic Search

    Stuart Mestelman; Douglas Welland

    1994-01-01

    Summary Posted offer and double auction pricing institutions are examples of fixed and flexible pricing institutions, respectively. In laboratory settings, double auction markets dominate posted offer institutions in terms of the amount of potential surplus which traders are able to extract. These results are invariant with respect to the experience of traders or the perishability of the good traded. Performance

  20. Metallurgy and performance of electrodeposited copper for flexible circuits

    Microsoft Academic Search

    H. D. Merchant; J. T. Wang; L. A. Giannuzzi; Y. L. Liu

    2000-01-01

    In this paper, we consider intrinsic properties of copper electrodeposited as plateup on polyimide substrate, thermal response of electrodeposited copper and fatigue performance of copper and copper\\/polyimide construction. The critical material characteristics examined are grain morphology and structure, crystallographic texture, microhardness, uniaxial strength and ductility and isothermal cyclic fatigue life. Given optimum processing conditions, copper plateup in flexible circuits displays

  1. A High-Performance Flexible Architecture for Cryptography

    Microsoft Academic Search

    R. Reed Taylor; Seth Copen Goldstein

    1999-01-01

    Cryptographic algorithms are more eciently implemented in custom hardware than in software running on general-purpose proces- sors. However, systems which use hardware implementations have signif- icant drawbacks: they are unable to respond to flaws discovered in the implemented algorithm or to changes in standards. In this paper we show how recongurable computing oers high performance yet flexible solu- tions for

  2. Overall Thermal Performance of Flexible Piping Under Simulated Bending Conditions

    NASA Technical Reports Server (NTRS)

    Fesmire, James E.; Augustynowicz, S. D.; Demko, J. A.; Thompson, Karen (Technical Monitor)

    2001-01-01

    Flexible, vacuum-insulated transfer lines for low-temperature applications have higher thermal losses than comparable rigid lines. Typical flexible piping construction uses corrugated tubes, inner and outer, with a multilayer insulation (MLI) system in the annular space. Experiments on vacuum insulation systems in a flexible geometry were conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The effects of bending were simulated by causing the inner tube to be eccentric with the outer tube. The effects of spacers were simulated in a controlled way by inserting spacer tubes for the length of the cylindrical test articles. Two material systems, standard MLI and a layered composite insulation (LCI), were tested under the full range of vacuum levels using a liquid nitrogen boiloff calorimeter to determine the apparent thermal conductivity (k-value). The results indicate that the flexible piping under simulated bending conditions significantly degrades the thermal performance of the insulation system. These data are compared to standard MLI for both straight and flexible piping configurations. The definition of an overall k-value for actual field installations (k(sub oafi)) is described for use in design and analysis of cryogenic piping systems.

  3. Chip Seals for Asphalt Concrete Pavements: A Proposed Emulsion Residue Specification and Existing Pavement Texture Evaluation

    E-print Network

    Hoyt, Denise

    2012-07-16

    from chip seal emulsions; and investigation of texture measurement methods for assessing existing pavement macrotexture before a chip seal is placed. The performance graded (PG) asphalt binder specification, which was developed to characterize asphalt...

  4. Precast concrete pavements

    NASA Astrophysics Data System (ADS)

    Rollings, R. S.; Chou, Y. T.

    1981-11-01

    This report reviewed published literature on precast concrete pavements and found that precast concrete pavements have had some limited application in airfields, roads, and storage areas. This review of past experience and an analytical study of precast slabs concluded that existing design and construction techniques can be adapted for use with precast concrete pavements, but more work is needed to develop effective and easily constructed load transfer designs for slab joints. Precast concrete does not offer any advantage for conventional pavements due to its high cost and surface roughness, but it may find applications for special problems such as construction in adverse weather, subgrade settlement, temporary pavements that need to be relocated, and military operations.

  5. Advanced Self-Healing Asphalt Composites in the Pavement Performance Field: Mechanisms at the Nano Level and New Repairing Methodologies.

    PubMed

    Agzenai, Yahya; Pozuelo, Javier; Sanz, Javier; Prez, Ignacio; Baselga, Juan

    2014-12-01

    In an effort to give a global view of this field of research, in this mini-review we highlight the most recent publications and patents focusing on modified asphalt pavements that contain certain reinforcing nanoparticles which impart desirable thermal, electrical and mechanical properties. In response to the increasing cost of asphalt binder and road maintenance, there is a need to look for alternative technologies and new asphalt composites, able to self-repair, for preserving and renewing the existing pavements. First, we will focus on the self-healing property of asphalt, the evidences that support that healing takes place immediately after the contact between the faces of a crack, and how the amount of healing can be measured in both the laboratory and the field. Next we review the hypothetical mechanisms of healing to understand the material behaviour and establish models to quantify the damage-healing process. Thereafter, we outline different technologies, nanotechnologies and methodologies used for self-healing paying particular attention to embedded micro-capsules, new nano-materials like carbon nanotubes and nano-fibres, ionomers, and microwave and induction heating processes. PMID:25479339

  6. Mediaprocessors in medical imaging for high performance and flexibility

    NASA Astrophysics Data System (ADS)

    Managuli, Ravi; Kim, Yongmin

    2002-05-01

    New high performance programmable processors, called mediaprocessors, have been emerging since the early 1990s for various digital media applications, such as digital TV, set-top boxes, desktop video conferencing, and digital camcorders. Modern mediaprocessors, e.g., TI's TMS320C64x and Hitachi/Equator Technologies MAP-CA, can offer high performance utilizing both instruction-level and data-level parallelism. During this decade, with continued performance improvement and cost reduction, we believe that the mediaprocessors will become a preferred choice in designing imaging and video systems due to their flexibility in incorporating new algorithms and applications via programming and faster-time-to-market. In this paper, we will evaluate the suitability of these mediaprocessors in medical imaging. We will review the core routines of several medical imaging modalities, such as ultrasound and DR, and present how these routines can be mapped to mediaprocessors and their resultant performance. We will analyze the architecture of several leading mediaprocessors. By carefully mapping key imaging routines, such as 2D convolution, unsharp masking, and 2D FFT, to the mediaprocessor, we have been able to achieve comparable (if not better) performance to that of traditional hardwired approaches. Thus, we believe that future medical imaging systems will benefit greatly from these advanced mediaprocessors, offering significantly increased flexibility and adaptability, reducing the time-to-market, and improving the cost/performance ratio compared to the existing systems while meeting the high computing requirements.

  7. Flexible body dynamic stability for high performance aircraft

    NASA Technical Reports Server (NTRS)

    Goforth, E. A.; Youssef, H. M.; Apelian, C. V.; Schroeder, S. C.

    1991-01-01

    Dynamic equations which include the effects of unsteady aerodynamic forces and a flexible body structure were developed for a free flying high performance fighter aircraft. The linear and angular deformations are assumed to be small in the body reference frame, allowing the equations to be linearized in the deformation variables. Equations for total body dynamics and flexible body dynamics are formulated using the hybrid coordinate method and integrated in a state space format. A detailed finite element model of a generic high performance fighter aircraft is used to generate the mass and stiffness matrices. Unsteady aerodynamics are represented by a rational function approximation of the doublet lattice matrices. The equations simplify for the case of constant angular rate of the body reference frame, allowing the effect of roll rate to be studied by computing the eigenvalues of the system. It is found that the rigid body modes of the aircraft are greatly affected by introducing a constant roll rate, while the effect on the flexible modes is minimal for this configuration.

  8. Flow structure and performance of a flexible plunging airfoil

    NASA Astrophysics Data System (ADS)

    Akkala, James Marcus

    An investigation was performed with the intent of characterizing the effect of flexibility on a plunging airfoil, over a parameter space applicable to birds and flapping MAVs. The kinematics of the motion was determined using of a high speed camera, and the deformations and strains involved in the motion were examined. The vortex dynamics associated with the plunging motion were mapped out using particle image velocimetry (PIV), and categorized according to the behavior of the leading edge vortex (LEV). The development and shedding process of the LEVs was also studied, along with their flow trajectories. Results of the flexible airfoils were compared to similar cases performed with a rigid airfoil, so as to determine the effects caused by flexibility. Aerodynamic loads of the airfoils were also measured using a force sensor, and the recorded thrust, lift and power coefficients were analyzed for dependencies, as was the overall propulsive efficiency. Thrust and power coefficients were found to scale with the Strouhal number defined by the trialing edge amplitude, causing the data of the flexible airfoils to collapse down to a single curve. The lift coefficient was likewise found to scale with trailing edge Strouhal number; however, its data tended to collapse down to a linear relationship. On the other hand, the wake classification and the propulsive efficiency were more successfully scaled by the reduced frequency of the motion. The circulation of the LEV was determined in each case and the resulting data was scaled using a parameter developed for this specific study, which provided significant collapse of the data throughout the entire parameter space tested.

  9. Infrared thermography and ground penetrating radar for airport pavements assessment

    Microsoft Academic Search

    A. Moropoulou; N. P. Avdelidis; M. Koui; A. Aggelopoulos; P. Karmis

    2002-01-01

    Non-destructive techniques, such as infrared thermography and ground penetrating radar, have the potential to produce rapid and accurate assessment of airport pavements. In this work, an examination of asphalt pavements situated at the International Airport of Athens in Greece, is performed. Infrared thermography and ground penetrating radar are introduced with the purpose of providing prompt and accurate condition assessment of

  10. Modeling the Hydrologic Processes of a Permeable Pavement System

    EPA Science Inventory

    A permeable pavement system can capture stormwater to reduce runoff volume and flow rate, improve onsite groundwater recharge, and enhance pollutant controls within the site. A new unit process model for evaluating the hydrologic performance of a permeable pavement system has be...

  11. Pervious Pavement System Evaluation

    EPA Science Inventory

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, grade...

  12. Automated pavement crack detection

    E-print Network

    Rao, Ashok Madhava

    1991-01-01

    AUTOMATED PAVEMENT CRACK DETECTION A Thesis by ASHOK MADHAVA RAO Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1991 Major Subject...: Electrical Engineering AUTOMATED PAVEMENT CRACK DETECTION A Thesis by ASHOK MADHAVA RAO Approved as to style and content by . c Norman C. Grisw d (Chair of Committ ) Nasser Kehtarnavaz (Member) g, J~, Karan Watson Robert L. Lytt (Member) Jo W...

  13. Human resource flexibility, organizational culture and firm performance: an investigation of multinational firms in Hong Kong

    Microsoft Academic Search

    Hang-Yue Ngo; Raymond Loi

    2008-01-01

    This article explores the relationships between human resource (HR) flexibility, organizational culture, and organizational performance. Drawing on previous works, we develop a conceptual model that links the constructs together. It is hypothesized that the three sub-dimensions of HR flexibility (i.e. employee skill flexibility, employee behaviour flexibility, and HR practice flexibility) affect adaptability culture, which in turn impacts HR-related and market-related

  14. Development of a Pavement Maintenance and Rehabilitation Project Formation and Prioritization Methodology that Reflects Agency Priorities and Improves Network Condition

    E-print Network

    Narciso, Paul John Ross

    2013-07-22

    budgetary constraint. Future pavement condition was projected using performance prediction models and the process is repeated throughout the planning horizon to produce a multi-year pavement management plan. Data from Bryan district, which consists of 7,075...

  15. Semiconductor wires and ribbons for high-performance flexible electronics.

    PubMed

    Baca, Alfred J; Ahn, Jong-Hyun; Sun, Yugang; Meitl, Matthew A; Menard, Etienne; Kim, Hoon-Sik; Choi, Won Mook; Kim, Dae-Hyeong; Huang, Young; Rogers, John A

    2008-01-01

    This article reviews the properties, fabrication and assembly of inorganic semiconductor materials that can be used as active building blocks to form high-performance transistors and circuits for flexible and bendable large-area electronics. Obtaining high performance on low temperature polymeric substrates represents a technical challenge for macroelectronics. Therefore, the fabrication of high quality inorganic materials in the form of wires, ribbons, membranes, sheets, and bars formed by bottom-up and top-down approaches, and the assembly strategies used to deposit these thin films onto plastic substrates will be emphasized. Substantial progress has been made in creating inorganic semiconducting materials that are stretchable and bendable, and the description of the mechanics of these form factors will be presented, including circuits in three-dimensional layouts. Finally, future directions and promising areas of research will be described. PMID:18615769

  16. Semiconducor wires and ribbons for high performance flexible electronics.

    SciTech Connect

    Sun, Y.; Baca, A. J.; Ahn, J.-H.; Meitl, M.; Menard, E.; Kim, H.-S; Choi, W.; Kim, D.-H; Huang, Y.; Rogers, J. A.; Center for Nanoscale Materials; Univ. of Illinois

    2008-01-01

    This article reviews the properties, fabrication and assembly of inorganic semiconductor materials that can be used as active building blocks to form high-performance transistors and circuits for flexible and bendable large-area electronics. Obtaining high performance on low temperature polymeric substrates represents a technical challenge for macroelectronics. Therefore, the fabrication of high quality inorganic materials in the form of wires, ribbons, membranes, sheets, and bars formed by bottom-up and top-down approaches, and the assembly strategies used to deposit these thin films onto plastic substrates will be emphasized. Substantial progress has been made in creating inorganic semiconducting materials that are stretchable and bendable, and the description of the mechanics of these form factors will be presented, including circuits in three-dimensional layouts. Finally, future directions and promising areas of research will be described.

  17. Performance Evaluation of Contract NetBased Heterarchical Scheduling for Flexible

    E-print Network

    Scheduling, Multiagent Systems, Contract Net Protocol, Produc tion Reservation, FMS, Job Shop, DistributedPerformance Evaluation of Contract NetBased Heterarchical Scheduling for Flexible Manufacturing This paper presents a heterarchical scheduling approach for flexible manufacturing systems. The approach

  18. Developing Flexible, High Performance Polymers with Self-Healing Capabilities

    NASA Technical Reports Server (NTRS)

    Jolley, Scott T.; Williams, Martha K.; Gibson, Tracy L.; Caraccio, Anne J.

    2011-01-01

    Flexible, high performance polymers such as polyimides are often employed in aerospace applications. They typically find uses in areas where improved physical characteristics such as fire resistance, long term thermal stability, and solvent resistance are required. It is anticipated that such polymers could find uses in future long duration exploration missions as well. Their use would be even more advantageous if self-healing capability or mechanisms could be incorporated into these polymers. Such innovative approaches are currently being studied at the NASA Kennedy Space Center for use in high performance wiring systems or inflatable and habitation structures. Self-healing or self-sealing capability would significantly reduce maintenance requirements, and increase the safety and reliability performance of the systems into which these polymers would be incorporated. Many unique challenges need to be overcome in order to incorporate a self-healing mechanism into flexible, high performance polymers. Significant research into the incorporation of a self-healing mechanism into structural composites has been carried out over the past decade by a number of groups, notable among them being the University of I1linois [I]. Various mechanisms for the introduction of self-healing have been investigated. Examples of these are: 1) Microcapsule-based healant delivery. 2) Vascular network delivery. 3) Damage induced triggering of latent substrate properties. Successful self-healing has been demonstrated in structural epoxy systems with almost complete reestablishment of composite strength being achieved through the use of microcapsulation technology. However, the incorporation of a self-healing mechanism into a system in which the material is flexible, or a thin film, is much more challenging. In the case of using microencapsulation, healant core content must be small enough to reside in films less than 0.1 millimeters thick, and must overcome significant capillary and surface tension forces to flow, mix and react to achieve healing. Vascular networks small enough to fit into such films must also overcome these same flow limitations. Self-healing has also been demonstrated in ionomeric substrates such as Surlyn , wherein the heat generated by a projectile impact triggers the latent ability of this substrate to flow back to its original shape. Recent work using Diels-Alder reactions have shown promise in bringing about actual reforming of broken chemical bonds to achieve self-healing [2]. All self-healing mechanisms that rely on the use of inherent latent substrate properties require some degree of polymer chain flow to achieve any significant level of healing.

  19. Analysis, testing and verification of the behavior of composite pavements under Florida conditions using a heavy vehicle simulator

    Microsoft Academic Search

    Patricio Enrique Tapia Gutierrez

    2007-01-01

    Whitetopping (WT) is a rehabilitation method to resurface deteriorated asphalt pavements. While some of these composite pavements have performed very well carrying heavy load, other have shown poor performance with early cracking. With the objective of analyzing the applicability of WT pavements under Florida conditions, a total of nine full-scale WT test sections were constructed and tested using a Heavy

  20. High-performance flexible microwave passives on plastic

    NASA Astrophysics Data System (ADS)

    Ma, Zhenqiang; Seo, Jung-Hun; Cho, Sang June; Zhou, Weidong

    2014-06-01

    We report the demonstration of bendable inductors, capacitors and switches fabricated on a polyethylene terephthalate (PET) substrate that can operate at high microwave frequencies. By employing bendable dielectric and single crystalline semiconductor materials, spiral inductors and metal-insulator-metal (MIM) capacitors with high quality factors and high resonance frequencies and single-pole, single-throw (SPST) switches were archived. The effects of mechanical bending on the performance of inductors, capacitors and switches were also measured and analyzed. We further investigated the highest possible resonance frequencies and quality factors of inductors and capacitors and, high frequency responses and insertion loss. These demonstrations will lead to flexible radio-frequency and microwave systems in the future.

  1. The impact of geology on the performance of a bituminous surfaced pavementa case study from southeastern Nigeria

    NASA Astrophysics Data System (ADS)

    Okagbue, C. O.; Uma, K. O.

    One of the multi-million Naira dual carriageways in Nigeria, the Enugu-Port Harcourt expressway, has continued to experience failure at some sections, namely the stretches covering Lokpaukwu, Lokpanta, and Leru. This road section which, unlike others, does not respond to regular and routine maintenance, is concentrated on one geologic formation, the Eze Aku Shale which has been intruded by a dolerite sill. The emplacement of the dolerite sill had resulted in intense fracturing of the shales in the vicinity of the intrusions which includes portions of where the express road crosses. The road problem is most severe where the dolerite sill is traced right under and across the road. There is evidence from the study that the road problem is linked to the geological/hydrogeological conditions of the area. For example, the problematic section of the road is built on a considerably jointed, fractured and weathered shale formation as a subgrade. The subgrade ultimately has low bearing capacity. The road is almost at the foot of an escarpment where there is a concentration of natural groundwater discharge. Most of the discharge zones including natural water courses are now almost blocked resulting in increased groundwater storage and rise in water table under the highway pavement. This leads to fast deterioration of the base course materials. The dolerite sill, where it crosses the road, is less than 2 m below the grade level. It impedes vertical infiltration as well as lateral groundwater flow. Thus its position with respect to the highway grade elevation leads to an almost perpetual wetting of the base and sub-base materials.

  2. Optical performance monitoring for dynamic and flexible photonic networks

    NASA Astrophysics Data System (ADS)

    Oda, Shoichiro; Yang, Jeng-Yuan; Akasaka, Youichi; Vassilieva, Olga; Yamauchi, Tomohiro; Aoki, Yasuhiko; Sekiya, Motoyoshi; Rasmussen, Jens C.

    2015-01-01

    Optical performance monitoring (OPM) is considered as an important tool in order to operate and manage dynamic, flexible, and thus complex photonic networks. In this paper, firstly we review recent studies on OPM and discuss its possible applications, such as failure diagnosis of transmitter, receiver, and other transport equipment, optimization of system reach design, and so on. We then present two different types of in-band OSNR monitor, consisting of an optical bandpass filter, a photo-detector, and a signal processer. Since the proposed monitor might be realized by the same hardware implementation as an optical channel monitor (OCM), this is potentially integrated with an OCM in a low-cost fashion. We also explain a BER monitor, which is realized by the same hardware configuration as the above in-band OSNR monitor. The BER in the method is estimated by monitoring OSNR including nonlinear noise as noise source and taking the imperfection of Tx, Rx, and other equipment into account. Finally we develop FPGA-based optical performance monitor prototype and experimentally demonstrate successful monitoring performance.

  3. Recycling of pavement materials

    E-print Network

    O'Neal, Randy Jim

    1976-01-01

    was recycled. Mixing was accom- plished by using a 10-by $0-foot drum mixer with a low efficiency wet wash. This mixer had an asphalt line in- side the drum and introduced $. 5 percent asphalt by weight into the old pavement which contained. ). 7 percent... material from old asphalt pavement and coarse aggregate. One and one- half percent emulsion was added. Air pollution seemed to be the biggest problem. Warren Brothers feel that the main objective of recycling is to utilize existing plants with minor...

  4. Incorporating uncertainty in the Life Cycle Cost Analysis of pavements

    E-print Network

    Swei, Omar Abdullah

    2012-01-01

    Life Cycle Cost Analysis (LCCA) is an important tool to evaluate the economic performance of alternative investments for a given project. It considers the total cost to construct, maintain, and operate a pavement over its ...

  5. Influence of concrete flexural strength on airport pavement thickness

    Microsoft Academic Search

    Tammam Merhej; Decheng Feng

    2011-01-01

    Federal aviation administration rigid and flexible iterative elastic layered design (FAARFIELD) software program became the exclusive approved method for airport pavement thickness design adopted by federal aviation administration (FAA) in the United States after the advisory circular AC150\\/5320-6E \\

  6. Pervious Pavement System Evaluation

    EPA Science Inventory

    Pervious pavement is a low impact development stormwater control. The Urban Watershed Management Branch of the U.S. Environmental Protection Agency in Edison, NJ, is evaluating concrete pavers as a popular implementation. The pollutant removal of a bench-scale permeable interlo...

  7. POROUS PAVEMENT: RESEARCH; DEVELOPMENT; AND DEMONSTRATION

    EPA Science Inventory

    This paper discusses the U.S. Environmental Protection Agency's porous pavement research program along with the economics, advantages, potential applications, and status and future research needs of porous pavements. Porous pavements are an available stormwater management techniq...

  8. MTG Flexible Combined Imager optical design and performances

    NASA Astrophysics Data System (ADS)

    Ouaknine, J.; Gode, S.; Napierala, B.; Viard, T.; Foerster, U.; Fray, S.; Peacoke, Patrick; Hartl, M.; Hallibert, P.; Durand, Y.

    2013-09-01

    Meteosat Third Generation is the next ESA Program of Earth Observation dedicated to Nowcasting and very short term Weather Forecasting (NWC), medium/short range Global and Regional Numerical Weather Prediction (NWP), and Climate and Air Composition Monitoring. The satellites will be operating from the Geostationary orbit using a 3 axes stabilized platform. The main instrument is called the Flexible Combined Imager (FCI), currently under development by Thales Alenia Space France (TAS-F). This instrument will provide full images of the Earth every 10 minutes in 16 spectral channels between 0.44 and 13.3 ?m, with a ground resolution from 0.5 km to 2 km. The FCI is composed of a TMA telescope developed by Kayser-Threde (KT), which includes a Scan mirror, and a calibration mechanism with an embedded black body dedicated to accurate in-flight IR radiometric calibration and a Metallic Neutral density for dedicated VNIR Sun calibration. The image produced by the telescope is split into several spectral groups by a spectral separation assembly (SSA) with dichroc beamsplitters. The output beams are collimated to ease the instrument integration, and reach the cold optics (CO-I) which focalize the optical beams onto the detectors. The cold optics and IR detectors are accurately positioned inside a common cryostat to improve registration between spectral channels. Spectral filters are integrated on top of the detectors in order to achieve the required spectral selection. This article will describe the optical design and the main optical performances of the FCI: image quality, very high line-of-sight stability, and an efficient stray-light rejection thanks to the implementation of dedicated baffles and a stringent control of contamination. The FCI currently under development is expected to exhibit a significant improvement of performances with respect to Meteosat Second Generation satellites.

  9. Platypus: Design and Implementation of a Flexible High Performance Object Store.

    E-print Network

    He, Zhen

    Platypus: Design and Implementation of a Flexible High Performance Object Store. Zhen He1, Stephen. This paper reports the design and implementation of Platypus, a trans- actional object store. The twin goals of flexibility and performance dominate the design of Platypus. The design includes: support for SMP concurrency

  10. Development of statistical wet weather model to evaluate frictional properties at the pavement-tire interface on hot mix asphalt concrete

    E-print Network

    Bedi, Harpreet

    2001-01-01

    Skid resistance on wet pavements is influenced by friction at the tire-pavement interface as well as overall hot mix asphalt (HMA) performance. It is important to control aggregate, asphalt, and mix properties to achieve desirable frictional...

  11. Fatigue behavior of rubber modified pavements. Final report, 1994-1996

    SciTech Connect

    Raad, L.; Saboundjian, S.

    1997-05-01

    Over the last 15 years, a number of rubberized pavement projects have been built in Alaska. Initial laboratory and field investigations sponsored by the Alaska Department of Transportation and Public Facilities (AKDOT&PF) and conducted by Raad et al. (1995) indicated improved fatigue performance of the rubberized sections in comparison with conventional asphalt concrete pavements. The report presents the results of a follow-up investigation to develop design equations for rubberized pavements in Alaska.

  12. Analysis of Instrumentation Selection and Placement to Monitor the Hydrologic Performance of Permeable Pavement Systems and Bioinfiltration Areas at the Edison Environmental Center in New Jersey

    EPA Science Inventory

    In 2009, the U.S. Environmental Protection Agency constructed a 0.4-ha (1-ac) parking lot surfaced with three different permeable pavement types (interlocking concrete pavers, porous concrete, and porous asphalt) and six bioinfiltration areas with three different drainage area to...

  13. Impact of flexible scheduling on employee performance regarding stress and work-family conflict

    Microsoft Academic Search

    Raja Abdul Ghafoor Khan; Furqan Ahmad Khan; Muhammad Aslam Khan; Mohsin Shakeel

    2011-01-01

    Stress, work-family conflicts and flexible scheduling are three of the most important elements in organizational studies. The focus of current study is to understand the effect of Stress,work family conflicts and flexible scheduling on employees performance and also to understand whether flexible scheduling helps in reducing stress and work-family conflicts or not. The back bone of this study is the

  14. Performance and system flexibility of the CDF hardware event builder

    Microsoft Academic Search

    T. M. Shaw; K. Schurecht; P. K. Sinervo

    1991-01-01

    The CDF (Collider Detector Facility) hardware event builder, a flexible system built from a combination of three different 68020-based single width Fastbus modules, is discussed. The system may contain as few as three boards or as many as fifteen, depending on the specific application. Functionally, the boards receive a command to read out the raw event data from a set

  15. Equations for predicting the layer stiffness moduli in pavement systems containing lime-flyash stabilized materials

    E-print Network

    Alam, Shah Manzoor

    1984-01-01

    properties from Dynaflect data for the Texas flexible pave- ment system. For pavements of known thickness resting on homogenous subgrade of infinite depth and assuming a Poisson's ratio of 0. 5, Scrivner's approximated equation is of the general form: 4E...EOUATIONS FOR PREDICTING THE LAYER STIFFNESS ' MODULI IN PAVEMENT SYSTEMS CONTAINING LIME-FLYASH STABILIZED MATERIALS A Thesis by SHAH MANZOOR ALAM Submitted to the Graduate College of Texas AN University in partial fulfillment...

  16. Quantitative performance-based evaluation of a procedure for flexible design concept generation

    E-print Network

    Cardin, Michel-Alexandre, 1979-

    2011-01-01

    This thesis presents an experimental methodology for objective and quantitative design procedure evaluation based on anticipated lifecycle performance of design concepts, and a procedure for flexible design concept generation. ...

  17. Flexible Carbon Nanotube Films for High Performance Strain Sensors

    PubMed Central

    Kanoun, Olfa; Mller, Christian; Benchirouf, Abderahmane; Sanli, Abdulkadir; Dinh, Trong Nghia; Al-Hamry, Ammar; Bu, Lei; Gerlach, Carina; Bouhamed, Ayda

    2014-01-01

    Compared with traditional conductive fillers, carbon nanotubes (CNTs) have unique advantages, i.e., excellent mechanical properties, high electrical conductivity and thermal stability. Nanocomposites as piezoresistive films provide an interesting approach for the realization of large area strain sensors with high sensitivity and low manufacturing costs. A polymer-based nanocomposite with carbon nanomaterials as conductive filler can be deposited on a flexible substrate of choice and this leads to mechanically flexible layers. Such sensors allow the strain measurement for both integral measurement on a certain surface and local measurement at a certain position depending on the sensor geometry. Strain sensors based on carbon nanostructures can overcome several limitations of conventional strain sensors, e.g., sensitivity, adjustable measurement range and integral measurement on big surfaces. The novel technology allows realizing strain sensors which can be easily integrated even as buried layers in material systems. In this review paper, we discuss the dependence of strain sensitivity on different experimental parameters such as composition of the carbon nanomaterial/polymer layer, type of polymer, fabrication process and processing parameters. The insights about the relationship between film parameters and electromechanical properties can be used to improve the design and fabrication of CNT strain sensors. PMID:24915183

  18. Flexible carbon nanotube films for high performance strain sensors.

    PubMed

    Kanoun, Olfa; Mller, Christian; Benchirouf, Abderahmane; Sanli, Abdulkadir; Dinh, Trong Nghia; Al-Hamry, Ammar; Bu, Lei; Gerlach, Carina; Bouhamed, Ayda

    2014-01-01

    Compared with traditional conductive fillers, carbon nanotubes (CNTs) have unique advantages, i.e., excellent mechanical properties, high electrical conductivity and thermal stability. Nanocomposites as piezoresistive films provide an interesting approach for the realization of large area strain sensors with high sensitivity and low manufacturing costs. A polymer-based nanocomposite with carbon nanomaterials as conductive filler can be deposited on a flexible substrate of choice and this leads to mechanically flexible layers. Such sensors allow the strain measurement for both integral measurement on a certain surface and local measurement at a certain position depending on the sensor geometry. Strain sensors based on carbon nanostructures can overcome several limitations of conventional strain sensors, e.g., sensitivity, adjustable measurement range and integral measurement on big surfaces. The novel technology allows realizing strain sensors which can be easily integrated even as buried layers in material systems. In this review paper, we discuss the dependence of strain sensitivity on different experimental parameters such as composition of the carbon nanomaterial/polymer layer, type of polymer, fabrication process and processing parameters. The insights about the relationship between film parameters and electromechanical properties can be used to improve the design and fabrication of CNT strain sensors. PMID:24915183

  19. Evaluation of Surface and Subsurface Processes in Permeable Pavement Infiltration Trenches

    EPA Science Inventory

    The hydrologic performance of permeable pavement systems can be affected by clogging of the pavement surface and/or clogging at the interface where the subsurface storage layer meets the underlying soil. As infiltration and exfiltration are the primary functional mechanisms for ...

  20. Stormwater quality of spring-summer-fall effluent from three partial-infiltration permeable pavement systems and conventional asphalt pavement.

    PubMed

    Drake, Jennifer; Bradford, Andrea; Van Seters, Tim

    2014-06-15

    This study examined the spring, summer and fall water quality performance of three partial-infiltration permeable pavement (PP) systems and a conventional asphalt pavement in Ontario. The study, conducted between 2010 and 2012, compared the water quality of effluent from two Interlocking Permeable Concrete Pavements (AquaPave() and Eco-Optiloc()) and a Hydromedia() Pervious Concrete pavement with runoff from an Asphalt control pavement. The usage of permeable pavements can mitigate the impact of urbanization on receiving surface water systems through quantity control and stormwater treatment. The PP systems provided excellent stormwater treatment for petroleum hydrocarbons, total suspended solids, metals (copper, iron, manganese and zinc) and nutrients (total-nitrogen and total-phosphorus) by reducing event mean concentrations (EMC) as well as total pollutant loadings. The PPs significantly reduced the concentration and loading of ammonia (NH4(+)+NH3), nitrite (NO2(-)) and organic-nitrogen (Org-N) but increased the concentration and loading of nitrate (NO3(-)). The PP systems had mixed performances for the treatment of phosphate (PO4(3-)). The PP systems increased the concentration of sodium (Na) and chloride (Cl) but EMCs remained well below recommended levels for drinking water quality. Relative to the observed runoff, winter road salt was released more slowly from the PP systems resulting in elevated spring and early-summer Cl and Na concentrations in effluent. PP materials were found to introduce dissolved solids into the infiltrating stormwater. The release of these pollutants was verified by additional laboratory scale testing of the individual pavement and aggregate materials at the University of Guelph. Pollutant concentrations were greatest during the first few months after construction and declined rapidly over the course of the study. PMID:24681366

  1. Pervious Pavement System Evaluation- Abstract

    EPA Science Inventory

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, gra...

  2. Pavement management using hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Ayalew, Balehager; Gomez, Richard B.; Roper, William E.; Carrasco, Oscar

    2003-08-01

    Public Works facilities require up-to-date information on the health status of the road network they maintain. However, roadway maintenance and rehabilitation involves the greatest portion of a municipality's annual operating budget. Government officials use various technologies such as a pavement management system to assist in making better decisions about their roadways systems, pavement condition, history, and projects. Traditionally, manual surveying has served as the method of obtaining this information. To better assist in decision-making, a regionally specific spectral library for urban areas is being developed and used in conjunction with hyperspecrtal imaging, to map urban materials and pavement conditions. A Geographical Information and Positioning System (GIS/GPS) will also be implemented to overlay relative locations. This paper will examine the benefits of using hyperspectral imaging over traditional methods of roadway maintenance and rehabilitation for pavement management applications. In doing so, we will identify spatial and spectral requirements for successful large-scale road feature extraction.

  3. CRACKSCOPEAUTOMATIC PAVEMENT CRACKING INSPECTION SYSTEM

    E-print Network

    Texas at Austin, University of

    0-5708-P4 CRACKSCOPEAUTOMATIC PAVEMENT CRACKING INSPECTION SYSTEM Authors: Bugao Xu, Ph.D. and PScope .................................................................................................................. 11 3.2 Camera connection.................................................................................................................14 3.4 Camera control

  4. Adaptive prediction of pavement performance

    E-print Network

    Zulyaminayn, Mohammed

    2002-01-01

    (3) Cracking Log?(p?) = a, + ' +a, x(d?+a, )+a, xLog?(E, o) d. +a, Log?(P, ) = a, + a, xLog?(E, ) + a, xLvg, ?(d. +a, ) where, p, , P, . = parameters of the sigmoidal curve for cracking d, = overlay thickness, inches Eso = subgrade modulus, psi... (referred to as coefficient "o") t = log, ( I / age ) a, b, c = model coefficients Depending on the model coefficients, the curve can be a straight line, convex, concave or S-shaped with various degrees of curvature Individual distresses are predicted...

  5. GPR used in combination with other NDT methods for assessing pavements in PPP projects

    NASA Astrophysics Data System (ADS)

    Loizos, Andreas; Plati, Christina

    2014-05-01

    In the recent decades, Public-Private Partnerships (PPP) has been adopted for highway infrastructure procurement in many countries. PPP projects typically take the form of a section of highway and connecting roadways which are to be construction and managed for a given concession period. Over the course of the highway concession period, the private agency takes over the pavement maintenance and rehabilitation duties. On this purpose, it is critical to find the most cost effective way to maintain the infrastructure in compliance with the agreed upon performance measures and a Pavement Management Systems (PMS) is critical to the success of this process. For the prosperous operation of a PMS it is necessary to have appropriate procedures for pavement monitoring and evaluation, which is important in many areas of pavement engineering. Non Destructive Testing (NDT) has played a major role in pavement condition monitoring, assessments and evaluation accomplishing continuous and quick collection of pavement data. The analysis of this data can lead to indicators related to trigger values (criteria) that define the pavement condition based on which the pavement "health" is perceived helping decide whether there is the need or not to intervene in the pavement. The accomplished perception appoints required management activities for preserving pavements in favor not only of the involved highway/road agencies but also of users' service. Amongst NDT methods Ground Penetrating Radar (GPR) seems to be a very powerful toll, as it provides a range of condition and construction pavement information. It can support effectively the implementation of PMS activities in the framework of pavement monitoring and evaluation. Given that, the present work aims to the development and adaptation of a protocol for the use of GPR in combination with other NDT methods, such as Falling Weight Deflectometer (FWD), for assessing pavements in PPP projects. It is based on the experience of Laboratory of Pavement Engineering of National Technical University of Athens (NTUA) gained through its research activities in various Greek PPP projects as well its involvement in several related European and International scientific actions. It is suggested that the implementation of such protocol could support the pavement management activities with respect to the needs of a PPP project. This is accomplished through the resulted advantages that include simplicity in application, economic benefits and familiarity that are very important factors towards the optimization of the resources and the utilization of the available information; both of them are required for the orderly operation of a PPP project. Acknowledgments: This work benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar."

  6. Thermal Insulation Performance of Flexible Piping for Use in HTS Power Cables

    NASA Technical Reports Server (NTRS)

    Fesmire, James E.; Augustynowicz, S. D.; Demko, J. A.; Thompson, Karen (Technical Monitor)

    2001-01-01

    High-temperature superconducting (HTS) cables that typically operate at temperatures below 80 K are being developed for power transmission. The practical application of HTS power cables will require the use of flexible piping to contain the cable and the liquid nitrogen coolant. A study of thermal performance of multilayer insulation (MLI) was conducted in geometries representing both rigid and flexible piping. This experimental study performed at the Cryogenics Test Laboratory of NASA Kennedy Space Center provides a framework for the development of cost-effective, efficient thermal insulation systems that will support these long-distance flexible lines containing HTS power cables. The overall thermal performance of the insulation system for a rigid configuration and for a flexible configuration, simulating a flexible HTS power cable, was determined by the steady-state liquid nitrogen boiloff method under the full range of vacuum levels. Two different cylindrically rolled material systems were tested: a standard MLI and a layered composite insulation (LCI). Comparisons of ideal MLI, MLI on rigid piping, and MLI between flexible piping are presented.

  7. Performance, scalability, and flexibility in the RAW network router

    E-print Network

    DeGangi, Anthony M

    2004-01-01

    Conventional high speed Internet routers are built using custom designed microprocessors, dubbed network processors, to efficiently handle the task of packet routing. While capable of meeting the performance demanded of ...

  8. Multidisciplinary structural design and optimization for performance, cost, and flexibility

    E-print Network

    Nadir, William David, 1979-

    2005-01-01

    Reducing cost and improving performance are two key factors in structural design. In the aerospace and automotive industries, this is particularly true with respect to design criteria such as strength, stiffness, mass, ...

  9. High performance of a solid-state flexible asymmetric supercapacitor based on graphene films

    NASA Astrophysics Data System (ADS)

    Choi, Bong Gill; Chang, Sung-Jin; Kang, Hyun-Wook; Park, Chan Pil; Kim, Hae Jin; Hong, Won Hi; Lee, Sanggap; Huh, Yun Suk

    2012-07-01

    Solid-state flexible energy storage devices hold the key to realizing portable and flexible electronic devices. Achieving fully flexible energy storage devices requires that all of the essential components (i.e., electrodes, separator, and electrolyte) with specific electrochemical and interfacial properties are integrated into a single solid-state and mechanically flexible unit. In this study, we describe the fabrication of solid-state flexible asymmetric supercapacitors based on an ionic liquid functionalized-chemically modified graphene (IL-CMG) film (as the negative electrode) and a hydrous RuO2-IL-CMG composite film (as the positive electrode), separated with polyvinyl alcohol-H2SO4 electrolyte. The highly ordered macroscopic layer structures of these films arising through direct flow self-assembly make them simultaneously excellent electrical conductors and mechanical supports, allowing them to serve as flexible electrodes and current collectors in supercapacitor devices. Our asymmetric supercapacitors have been optimized with a maximum cell voltage up to 1.8 V and deliver a high energy density (19.7 W h kg-1) and power density (6.8 kW g-1), higher than those of symmetric supercapacitors based on IL-CMG films. They can operate even under an extremely high rate of 10 A g-1 with 79.4% retention of specific capacitance. Their superior flexibility and cycling stability are evident in their good performance stability over 2000 cycles under harsh mechanical conditions including twisted and bent states. These solid-state flexible asymmetric supercapacitors with their simple cell configuration could offer new design and fabrication opportunities for flexible energy storage devices that can combine high energy and power densities, high rate capability, and long-term cycling stability.Solid-state flexible energy storage devices hold the key to realizing portable and flexible electronic devices. Achieving fully flexible energy storage devices requires that all of the essential components (i.e., electrodes, separator, and electrolyte) with specific electrochemical and interfacial properties are integrated into a single solid-state and mechanically flexible unit. In this study, we describe the fabrication of solid-state flexible asymmetric supercapacitors based on an ionic liquid functionalized-chemically modified graphene (IL-CMG) film (as the negative electrode) and a hydrous RuO2-IL-CMG composite film (as the positive electrode), separated with polyvinyl alcohol-H2SO4 electrolyte. The highly ordered macroscopic layer structures of these films arising through direct flow self-assembly make them simultaneously excellent electrical conductors and mechanical supports, allowing them to serve as flexible electrodes and current collectors in supercapacitor devices. Our asymmetric supercapacitors have been optimized with a maximum cell voltage up to 1.8 V and deliver a high energy density (19.7 W h kg-1) and power density (6.8 kW g-1), higher than those of symmetric supercapacitors based on IL-CMG films. They can operate even under an extremely high rate of 10 A g-1 with 79.4% retention of specific capacitance. Their superior flexibility and cycling stability are evident in their good performance stability over 2000 cycles under harsh mechanical conditions including twisted and bent states. These solid-state flexible asymmetric supercapacitors with their simple cell configuration could offer new design and fabrication opportunities for flexible energy storage devices that can combine high energy and power densities, high rate capability, and long-term cycling stability. Electronic supplementary information (ESI) available: Photograph and AFM images, XPS spectra, XRD patterns, TGA curves, and evaluated values of energy and power densities are shown in the ESI. See DOI: 10.1039/c2nr30991b

  10. Developing Flexible and High-performance Web Servers with Frameworks and Patterns

    E-print Network

    Schmidt, Douglas C.

    Developing Flexible and High-performance Web Servers with Frameworks and Patterns Douglas C frameworks and pat- terns address complexities that arise in the design and imple- mentation of high-performance preservation), and accidental (e.g., the contin- uous reinvention of key concepts and components). This pa- per

  11. Effect of wing inertia on hovering performance of flexible flapping wings Bo Yin and Haoxiang Luoa

    E-print Network

    Luo, Haoxiang

    Effect of wing inertia on hovering performance of flexible flapping wings Bo Yin and Haoxiang Luoa is applied to simulate the flow-structure interaction of a flapping wing during hovering flight. The wing al.4 performed a two-dimensional numerical simu- lation of the flow-structure interaction in hovering

  12. Effect of flexible working hours on employee satisfaction and performance: A field experiment

    Microsoft Academic Search

    Christopher Orpen

    1981-01-01

    64 federal workers were randomly assigned to flexible or fixed working hours, and after 6 mo they completed the Index of Job Satisfaction. In addition, their supervisors rated their 6-mo performance on a 9-point scale. Results indicate that flexitime caused a significant increase in worker satisfaction but had negligible effects on performance, whether assessed by output or ratings. Research should

  13. Pervious Pavement System Evaluation-Poster

    EPA Science Inventory

    Pervious pavement is a low impact development stormwater control. The Environmental Protection Agency's Urban Watershed Management Branch is evaluating interlocking concrete pavingstone pervious pavement systems. The pavingstones themselves are impermeable, but the spaces between...

  14. Asphalt Oxidation Kinetics and Pavement Oxidation Modeling

    E-print Network

    Jin, Xin

    2012-07-16

    Most paved roads in the United States are surfaced with asphalt. These asphalt pavements suffer from fatigue cracking and thermal cracking, aggravated by the oxidation and hardening of asphalt. This negative impact of asphalt oxidation on pavement...

  15. Analysis of Load Stress for Asphalt Pavement of Lean Concrete Base

    NASA Astrophysics Data System (ADS)

    Lijun, Suo; Xinwu, Wang

    The study revealed that whether it is early distresses in asphalt pavement or not depends largely on working performance of base. In the field of asphalt pavement, it is widely accepted that lean concrete base, compared with the general semi-rigid base, has better working performance, such as high strength and good eroding resistance. Problem of early distresses in asphalt pavement, which caused by more traffic loadings, can be settled effectively when lean concrete is used in asphalt pavement. Traffic loading is important parameter used in the analysis of the new pavement design. However, few studies have done extensive and intensive research on the load stress for asphalt pavement of lean concrete base. Because of that, it is necessary to study the load stress for the asphalt pavement. In the paper, first of all, three-dimension finite element model of the asphalt pavement is created for the aim of doing mechanical analysis for the asphalt pavement. And then, the two main objectives of this study are investigated. One is analysis for load stress of lean concrete base, and the other is analysis for load stress of asphalt surface. The results show that load stress of lean concrete base decreases, decrease and increase with increase of base's thickness, surface's thickness and ratio of base's modulus to foundation's modulus respectively. So far as the asphalt surface is concerned, maximum shearing stress, which is caused by load, is evident in asphalt surface which is located in transverse contraction joint of lean concrete base of asphalt pavement. Maximum shearing stress decrease, decrease, decrease and increase respectively with increase of the surface's modulus, the surface's thickness, base's thickness and ratio of base's modulus to foundation's modulus.

  16. Pavement recycling guidelines for state and local governments: Participant`s reference book. Final report, September 1995--December 1997

    SciTech Connect

    Kandhal, P.S.; Mallick, R.B.

    1997-12-01

    Recycling or reuse of existing asphalt pavement materials to produce new pavement materials has the following advantages: (1) reduced costs of construction, (2) conservation of aggregate and binder, (3) preservation of the existing pavement geometrics, (4) preservation of the environment, and (5) conservation of energy. This document was prepared to provide the following information on recycling of asphalt pavements: (1) performance data, (2) legislation/specification limits, (3) selection of pavement for recycling and recycling strategies, (4) economics of recycling, and (5) structural design of recycled pavements. The following recycling methods have been included: hot-mix asphalt recycling (both batch and drum plants), asphalt surface recycling, hot-in-place recycling, cold-mix asphalt recycling, and full depth reclamation. Materials and mix design, construction methods and equipment, case histories and quality control/quality assurance have been discussed for all recycling methods.

  17. Research of infrared laser based pavement imaging and crack detection

    NASA Astrophysics Data System (ADS)

    Hong, Hanyu; Wang, Shu; Zhang, Xiuhua; Jing, Genqiang

    2013-08-01

    Road crack detection is seriously affected by many factors in actual applications, such as some shadows, road signs, oil stains, high frequency noise and so on. Due to these factors, the current crack detection methods can not distinguish the cracks in complex scenes. In order to solve this problem, a novel method based on infrared laser pavement imaging is proposed. Firstly, single sensor laser pavement imaging system is adopted to obtain pavement images, high power laser line projector is well used to resist various shadows. Secondly, the crack extraction algorithm which has merged multiple features intelligently is proposed to extract crack information. In this step, the non-negative feature and contrast feature are used to extract the basic crack information, and circular projection based on linearity feature is applied to enhance the crack area and eliminate noise. A series of experiments have been performed to test the proposed method, which shows that the proposed automatic extraction method is effective and advanced.

  18. Making "Magic" Sidewalks of Pervious Pavement

    NSDL National Science Digital Library

    2014-09-18

    Students use everyday building materialssand, pea gravel, cement and waterto create and test pervious pavement. They learn what materials make up a traditional, impervious concrete mix and how pervious pavement mixes differ. Groups are challenged to create their own pervious pavement mixes, experimenting with material ratios to evaluate how infiltration rates change with different mix combinations.

  19. Solution-processed high-performance colloidal quantum dot tandem photodetectors on flexible substrates

    SciTech Connect

    Jiang, Zhenyu; You, Guanjun; Wang, Li; Liu, Jie; Xu, Jian, E-mail: jianxu@engr.psu.edu [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Hu, Wenjia [China Tianchen Engineering Corporation, Tianjin 300400 (China); Zhang, Yu [State Key Laboratory on Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

    2014-08-28

    We report a high-performance colloidal quantum dot (CQD)-based near-infrared tandem photodetector fabricated on flexible substrates via solution-processed method. The tandem photodetector on poly(ethylene terephthalate) substrates exhibited low dark current and high detectivities over ?8.8??10{sup 11} Jones at near infrared range at ?0.5?V bias and over ?10{sup 13} Jones near 0 bias. The critical bend radii of ?8?mm and ?3?mm have been demonstrated for tensile and compressive bending, respectively. The performance of photodetectors remains stable under mechanical stress, making PbSe CQD material a promise candidate for flexible infrared sensing applications.

  20. Fatigue properties of rubber modified pavements. Final report

    SciTech Connect

    Raad, L.; Saboundjian, S.; Yuan, X.

    1995-05-01

    This report presents results of a study to determine the fatigue behavior of rubber modified pavements in Alaska in comparison with conventional asphalt concrete pavements. Laboratory studies were conducted on field specimens using the flexural fatigue test in the controlled-displacement mode. Tests were performed at 72 deg F and 40 deg F. Tested materials include (1) conventional HMA with AC 2.5 and AC 5; (2) PlusRide RUMAC with AC 5; (3) asphalt-rubber concrete with AC 2.5 (wet Process); and (4) rubberized asphalt-rubber concrete with AC 2.5 (wet/dry process).

  1. Numerical study on the power extraction performance of a flapping foil with a flexible tail

    NASA Astrophysics Data System (ADS)

    Wu, J.; Shu, C.; Zhao, N.; Tian, F.-B.

    2015-01-01

    The numerical study on the power extraction performance of a flapping foil with a flexible tail is performed in this work. A NACA0015 airfoil is arranged in a two-dimensional laminar flow and imposed with a synchronous harmonic plunge and pitch rotary motion. A flat plate that is attached to the trailing edge of the foil is utilized to model a tail, and so they are viewed as a whole for the purpose of power extraction. In addition, the tail either is rigid or can deform due to the exerted hydrodynamic forces. To implement numerical simulations, an immersed boundary-lattice Boltzmann method is employed. At a Reynolds number of 1100 and the position of the pitching axis at third chord, the influences of the mass and flexibility of the tail as well as the frequency of motion on the power extraction are systematically examined. It is found that compared to the foil with a rigid tail, the efficiency of power extraction for the foil with a deformable tail can be improved. Based on the numerical analysis, it is indicated that the enhanced plunging component of the power extraction, which is caused by the increased lift force, directly contributes to the efficiency improvement. Since a flexible tail with medium and high masses is not beneficial to the efficiency improvement, a flexible tail with low mass together with high flexibility is recommended in the flapping foil based power extraction system.

  2. Porous Pavements in Cold Climates Part 1: Design, Installation, and

    E-print Network

    Porous Pavements in Cold Climates Part 1: Design, Installation, and Maintenance A Green-Graded Friction Courses (2002) 3 #12;Part I Overview 1. State of the Practice 2. Common Design and Installation Cold climate performance is strong Winter maintenance has tremendous potential salt reduction Design

  3. Measuring Clogging with Pressure Transducers in Permeable Pavement Strips

    EPA Science Inventory

    Two issues that have a negative affect on the long term hydrologic performance of permeable pavement systems are surface clogging and clogging at the interface with the underlying soil. Surface clogging limits infiltration capacity and results in bypass if runoff rate exceeds in...

  4. The sports performance application of vibration exercise for warm-up, flexibility and sprint speed

    Microsoft Academic Search

    Darryl Cochrane

    2011-01-01

    Since the turn of the 21st century, there has been a resurgence of vibration technology to enhance sport science especially for power and force development. However, vibration exercise has been trialled in other areas that are central to athlete performance such as warm-up, flexibility and sprint speed. Therefore, the aim of this review was to attempt to gain a better

  5. The Effects of Cognitive Flexibility and Openness to Change on College Students' Academic Performance

    ERIC Educational Resources Information Center

    Lin, Ya-Wei

    2013-01-01

    This research investigated the relationship between cognitive flexibility and openness to change and their effects on academic performance among college students at National Taiwan University in Taipei, Taiwan. Using a quantitative purposeful sampling strategy, data were collected in classroom settings from 770 undergraduate voluntary

  6. SAFEgress: A Flexible Platform to Study the Effect of Human and Social Behaviors on Egress Performance

    E-print Network

    Stanford University

    the important human factors on an egress situation and, thereby, improve the design of safe egress systems and egress performance. The focus of this paper is to show the effects of human and social behaviorsSAFEgress: A Flexible Platform to Study the Effect of Human and Social Behaviors on Egress

  7. Printable silicon for ultrahigh performance flexible electronic systems Home | About Us | Contact Us | For Media | Search

    E-print Network

    Rogers, John A.

    Us | For Media | Search RESEARCH Science General Business Archives NEWS This Year Archives ILLINOISPrintable silicon for ultrahigh performance flexible electronic systems Home | About Us | Contact IN THE NEWS PUBLICATIONS Inside Illinois II Archives II Advertising About II Postmarks QUICK SEARCH Advanced

  8. A Comparison of the Performance of Registered Nurse Students in Flexible and Traditional Clinical Courses.

    ERIC Educational Resources Information Center

    Wolfe, Mary L.; Sands, Rosetta F.

    An experiment was conducted at the University of Maryland at Baltimore to determine if performances would differ for registered nurses enrolled in a baccalaureate program in nursing depending on whether they participated in a flexible clinical scheduling (FLEX) program or in the traditional (non-FLEX) program. Fifty-four students took part in the

  9. HR flexibility and firm performance: analysis of a multi-level causal model

    Microsoft Academic Search

    Sumita Ketkar; P. K. Sett

    2009-01-01

    Human resource flexibility as a construct, how it develops, and its effect on firm performance have not received adequate attention in strategic HRM literature in spite of their obvious importance in today's dynamic competitive environment. Based on a study of 98 manufacturing and 103 service firms in India, this paper addresses these issues by developing and testing a multi-level model

  10. Towards a new generation of mission planning systems: Flexibility and performance

    NASA Technical Reports Server (NTRS)

    Gasquet, A.; Parrod, Y.; Desaintvincent, A.

    1994-01-01

    This paper presents some new approaches which are required for a better adequacy of Mission Planning Systems. In particular, the performance flexibility and genericity issues are discussed based on experience acquired through various Mission Planning systems developed by Matra Marconi Space.

  11. A converging route towards very high frequency, mechanically flexible, and performance stable integrated electronics

    NASA Astrophysics Data System (ADS)

    Lecavelier des Etangs-Levallois, Aurlien; Chen, Zhenkun; Lesecq, Marie; Lepilliet, Sylvie; Tagro, Yoann; Danneville, Franois; Robillard, Jean-Franois; Hoel, Virginie; Troadec, David; Gloria, Daniel; Raynaud, Christine; Ratajczak, Jacek; Dubois, Emmanuel

    2013-04-01

    The ability to realize flexible circuits integrating sensing, signal processing, and communicating capabilities is of central importance for the development of numerous nomadic applications requiring foldable, stretchable, and large area electronics. A key challenge is, however, to combine high electrical performance (i.e., millimeter wave, low noise electronics) with mechanical flexibility required for chip form adaptivity in addition to highly stable electrical performance upon deformation. Here, we describe a solution based on ultimate thinning and transfer onto a plastic foil of high frequency CMOS devices initially processed on conventional silicon-on-insulator wafers. We demonstrate a methodology relying on neutral plane engineering to provide high performance stability upon bending, by locating the active layer, i.e., the transistor channel, at the neutral fiber of the flexible system. Following this strategy, record frequency performance of flexible n-MOSFETs, featuring fT/fMAX of 120/145 GHz, is reported with relative variations limited to less than 5% even under aggressive bending on cylinders with curvature radii down to 12.5 mm.

  12. Use of Time Domain Reflectometers (TDRs) in Permeable Pavement Systems to Predict Maintenance Needs and Effectiveness

    EPA Science Inventory

    As the surface in permeable pavement systems clogs, infiltration capacity decreases, so maintenance is required to maintain hydrologic performance. There is limited direct guidance for determining when maintenance is needed to prevent surface runoff bypass. Research is being co...

  13. Air-stable, high-performance, flexible microsupercapacitor with patterned ionogel electrolyte.

    PubMed

    Kim, Daeil; Lee, Geumbee; Kim, Doyeon; Ha, Jeong Sook

    2015-03-01

    We describe the fabrication of air-stable, high-performance, planar microsupercapacitors (MSCs) on a flexible poly(ethylene terephthalate) substrate with patterned ionogel electrolyte, i.e., poly(ethylene glycol) diacrylate/1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and electrodes of spray-coated multiwalled carbon nanotubes. The flexible MSC showed good cyclability, retaining ?80% of initial capacitance after 30?000 cycles, and good mechanical stability down to a bending diameter of 3 mm under compressive stress; 95% of the initial capacitance was retained after 1000 bending cycles. The MSC had high electrochemical stability with retaining 90% of its initial capacitance for 8 weeks in air. Furthermore, vertical stacking of MSCs with patterned solid film of ionogel electrolyte could increase the areal capacitance dramatically. This flexible MSC has potential applications as an energy-storage device in micro/nanoelectronics, without encapsulation for air stability. PMID:25665151

  14. Pavement Smoothness for Illinois DOT -Doug Dirks 1. Briefly summarize your current pavement smoothness requirements. See below.

    E-print Network

    Pavement Smoothness for Illinois DOT - Doug Dirks 1. Briefly summarize your current pavement? N/A Illinois has both standard specifications and a special provision for pavement smoothness-Depth HMA Pavement 407.09 PCC Pavement 420.10 The following is a link to Division 400 of the Illinois

  15. The role of urban surfaces (permeable pavements) in regulating drainage and evaporation: development of a laboratory simulation experiment

    Microsoft Academic Search

    C. T. Andersen; I. D. L. Foster; C. J. Pratt

    1999-01-01

    Permeable pavements and similar stormwater control devices have not been exploited in the UK, in part because their adoption has been hindered by a lack of detailed knowledge of their hydrological performance. This paper describes a research programme that produced detailed information on the hydrological behaviour of a car park surface. The study involved the construction of full-scale permeable pavement

  16. Pavement Design TTP Orientation Seminar

    E-print Network

    Handy, Susan L.

    the "good old" days? #12;Traffic Variables Highways - it's the trucks Loads Tire pressures Speeds? are your loads controlled? #12;Big Truck - 1960 #12;Big Truck - 2001 #12;Super Single Tires #12;Australian of these materials can be perpetually recyclable into the same infrastructure #12;#12;#12;#12;Pavements

  17. Pavement Design TTP Orientation Seminar

    E-print Network

    Handy, Susan L.

    Variables Highways - it's the trucks Loads Tire pressures Speeds Dynamics (interaction controlled? #12;Big Truck - 1960 #12;Big Truck - 2001 #12;Super Single Tires #12;Australian for "truck" "Road of these materials can be perpetually recyclable into the same infrastructure #12;#12;#12;#12;Pavements

  18. The Concrete and Pavement Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as

  19. Nondestructive Evaluation of Pavements Ultrasonic

    E-print Network

    Minnesota, University of

    Nondestructive Evaluation of Pavements Ð Ultrasonic Tomography Kyle Hoegh, Graduate Student Dr. Lev ­! The transducers act on the test object surface with oscillating piezoelectric elements for wave production from the specs (about 3 miles of testing in 50 ft intervals). Field Application ­ Atlanta Georgia

  20. Bituminous pavement recycling Aravind K. and Animesh Das

    E-print Network

    Das, Animesh

    Bituminous pavement recycling Aravind K. and Animesh Das Department of Civil Engineering IIT Kanpur Introduction The bituminous pavement rehabilitation alternatives are mainly overlaying, recycling and reconstruction. In the recycling process the material from deteriorated pavement, known as reclaimed asphalt

  1. Integrated Materials and Construction Practices (IMCP) for Concrete Pavement

    E-print Network

    Integrated Materials and Construction Practices (IMCP) for Concrete Pavement Workshop Participant Handbook Prepared for Prepared by Federal Highway Administration National Concrete Pavement Technology and Construction Practices for Concrete Pavements Workshop Participant Handbook--Front Matter i Technical Report

  2. Aerodynamic performance of a hovering hawkmoth with flexible wings: a computational approach

    PubMed Central

    Nakata, Toshiyuki; Liu, Hao

    2012-01-01

    Insect wings are deformable structures that change shape passively and dynamically owing to inertial and aerodynamic forces during flight. It is still unclear how the three-dimensional and passive change of wing kinematics owing to inherent wing flexibility contributes to unsteady aerodynamics and energetics in insect flapping flight. Here, we perform a systematic fluid-structure interaction based analysis on the aerodynamic performance of a hovering hawkmoth, Manduca, with an integrated computational model of a hovering insect with rigid and flexible wings. Aerodynamic performance of flapping wings with passive deformation or prescribed deformation is evaluated in terms of aerodynamic force, power and efficiency. Our results reveal that wing flexibility can increase downwash in wake and hence aerodynamic force: first, a dynamic wing bending is observed, which delays the breakdown of leading edge vortex near the wing tip, responsible for augmenting the aerodynamic force-production; second, a combination of the dynamic change of wing bending and twist favourably modifies the wing kinematics in the distal area, which leads to the aerodynamic force enhancement immediately before stroke reversal. Moreover, an increase in hovering efficiency of the flexible wing is achieved as a result of the wing twist. An extensive study of wing stiffness effect on aerodynamic performance is further conducted through a tuning of Young's modulus and thickness, indicating that insect wing structures may be optimized not only in terms of aerodynamic performance but also dependent on many factors, such as the wing strength, the circulation capability of wing veins and the control of wing movements. PMID:21831896

  3. Automated management for pavement inspection system (AMPIS)

    NASA Astrophysics Data System (ADS)

    Chung, Hung Chi; Girardello, Roberto; Soeller, Tony; Shinozuka, Masanobu

    2003-08-01

    An automated in-situ road surface distress surveying and management system, AMPIS, has been developed on the basis of video images within the framework of GIS software. Video image processing techniques are introduced to acquire, process and analyze the road surface images obtained from a moving vehicle. ArcGIS platform is used to integrate the routines of image processing and spatial analysis in handling the full-scale metropolitan highway surface distress detection and data fusion/management. This makes it possible to present user-friendly interfaces in GIS and to provide efficient visualizations of surveyed results not only for the use of transportation engineers to manage road surveying documentations, data acquisition, analysis and management, but also for financial officials to plan maintenance and repair programs and further evaluate the socio-economic impacts of highway degradation and deterioration. A review performed in this study on fundamental principle of Pavement Management System (PMS) and its implementation indicates that the proposed approach of using GIS concept and its tools for PMS application will reshape PMS into a new information technology-based system providing a convenient and efficient pavement inspection and management.

  4. Investigation and application of fractured slab techniques for PCC pavements. Final report, May 1996--April 1999

    SciTech Connect

    Owusu-Ababio, S.; Nelson, T.

    1999-04-01

    Slab fracture techniques, including break and seat, crack and seat, and rubblization have in recent years gained widespread recognition among pavement engineers as means for eliminating or substantially reducing the potential for reflective cracking in hot mix asphalt (HMA) overlays over portland cement concrete (PCC) pavements. Guidelines for the use of these techniques in Wisconsin, however, have not been clearly established. This reports examines the PCC rehabilitation techniques of rubblization and crack and seat used in Wisconsin and their performance. The report examines the literature and evaluates the critical issues associated with the use of PCC fracture techniques by various agencies. Several elements pertinent to fracture techniques are also identified and incorporated in a database for in-service fractured overlaid PCC pavements in Wisconsin. In addition, the in-service performance of cracked and seated and rubblized pavements in Wisconsin is evaluated.

  5. Effects of flexibility on AGS performance. [Annular suspension pointing system Gimbal System aboard Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Shelton, H. L.; Cunningham, D. C.; Worley, H. E.; Seltzer, S. M.

    1982-01-01

    The Marshall Space Flight Center has had under development the Annular Suspension Pointing System Gimbal System (AGS) since early 1979. The AGS is an Orbiter cargo bay mounted subarcsecond 3 axis inertial pointer that can accommodate a wide range of payloads which require more stringent pointing than the Orbiter can provide. This paper will describe the AGS, state performance requirements and the control law configuration. Then an approach to investigating the flexible body effects on control system design will be discussed.

  6. AUTOMATED PAVEMENT IMAGING PROGRAM (APIP) FOR PAVEMENT CRACKS CLASSIFICATION AND QUANTIFICATION - A PHOTOGRAMMETRIC APPROACH

    Microsoft Academic Search

    M. Mustaffar; T. C. Ling

    1998-01-01

    The evaluation of pavement conditions is an important part of pavement management. Traditionally, pavement condition data are gathered by human inspectors who walk or drive along the road to assess the distresses and subsequently produce report sheets. This visual survey method is not only time consuming and costly but more importantly it compromises the safety of the field personnel. With

  7. Comparative field permeability measurement of permeable pavements using ASTM C1701 and NCAT permeameter methods.

    PubMed

    Li, Hui; Kayhanian, Masoud; Harvey, John T

    2013-03-30

    Fully permeable pavement is gradually gaining support as an alternative best management practice (BMP) for stormwater runoff management. As the use of these pavements increases, a definitive test method is needed to measure hydraulic performance and to evaluate clogging, both for performance studies and for assessment of permeability for construction quality assurance and maintenance needs assessment. Two of the most commonly used permeability measurement tests for porous asphalt and pervious concrete are the National Center for Asphalt Technology (NCAT) permeameter and ASTM C1701, respectively. This study was undertaken to compare measured values for both methods in the field on a variety of permeable pavements used in current practice. The field measurements were performed using six experimental section designs with different permeable pavement surface types including pervious concrete, porous asphalt and permeable interlocking concrete pavers. Multiple measurements were performed at five locations on each pavement test section. The results showed that: (i) silicone gel is a superior sealing material to prevent water leakage compared with conventional plumbing putty; (ii) both methods (NCAT and ASTM) can effectively be used to measure the permeability of all pavement types and the surface material type will not impact the measurement precision; (iii) the permeability values measured with the ASTM method were 50-90% (75% on average) lower than those measured with the NCAT method; (iv) the larger permeameter cylinder diameter used in the ASTM method improved the reliability and reduced the variability of the measured permeability. PMID:23434738

  8. Theoretical and field evaluation of interaction between ultra-thin whitetopping and existing asphalt pavement

    Microsoft Academic Search

    Deividi Da S. Pereira; Jos T. Balbo; Lev Khazanovich

    2006-01-01

    Ultra-thin concrete overlays or ultra-thin whitetopping (UTW), are an attractive alternative to traditional practices for the rehabilitation of asphalt pavements. However, it is widely accepted that the exiting pavement should have substantial stiffness to make a UTW a rehabilitation option. This paper re-examines this hypothesis using the performance results and structural evaluation of two experimental sections in Brazil. It is

  9. Investigation of mechanical properties of pavement through electromagnetic techniques

    NASA Astrophysics Data System (ADS)

    Benedetto, Andrea; Tosti, Fabio; D'Amico, Fabrizio

    2014-05-01

    Ground-penetrating radar (GPR) is considered as one of the most flexible geophysical tools that can be effectively and efficiently used in many different applications. In the field of pavement engineering, GPR can cover a wide range of uses, spanning from physical to geometrical inspections of pavements. Traditionally, such inferred information are integrated with mechanical measurements from other traditional (e.g. plate bearing test) or non-destructive (e.g. falling weight deflectometer) techniques, thereby resulting, respectively, in time-consuming and low-significant measurements, or in a high use of technological resources. In this regard, the new challenge of retrieving mechanical properties of road pavements and materials from electromagnetic measurements could represent a further step towards a greater saving of economic resources. As far as concerns unpaved and bound layers it is well-known that strength and deformation properties are mostly affected, respectively, by inter-particle friction and cohesion of soil particles and aggregates, and by bitumen adhesion, whose variability is expressed by the Young modulus of elasticity. In that respect, by assuming a relationship between electromagnetic response (e.g. signal amplitudes) and bulk density of materials, a reasonable correlation between mechanical and electric properties of substructure is therefore expected. In such framework, a pulse GPR system with ground-coupled antennae, 600 MHz and 1600 MHz centre frequencies was used over a 4-m30-m test site composed by a flexible pavement structure. The horizontal sampling resolution amounted to 2.410-2 m. A square regular grid mesh of 836 nodes with a 0.40-m spacing between the GPR acquisition tracks was surveyed. Accordingly, a light falling weight deflectometer (LFWD) was used for measuring the elastic modulus of pavement at each node. The setup of such instrument consisted of a 10-kg falling mass and a 100-mm loading plate so that the influence domain of the elasticity measure could be comparable to that of the radar signal. Good agreement were found between high Young modulus values and repaved zones, whereas damaged areas were characterized by lower values of E. Tomographic maps of amplitudes along the z axis were extracted up to a depth of z

  10. High Performance, Robust Control of Flexible Space Structures: MSFC Center Director's Discretionary Fund

    NASA Technical Reports Server (NTRS)

    Whorton, M. S.

    1998-01-01

    Many spacecraft systems have ambitious objectives that place stringent requirements on control systems. Achievable performance is often limited because of difficulty of obtaining accurate models for flexible space structures. To achieve sufficiently high performance to accomplish mission objectives may require the ability to refine the control design model based on closed-loop test data and tune the controller based on the refined model. A control system design procedure is developed based on mixed H2/H(infinity) optimization to synthesize a set of controllers explicitly trading between nominal performance and robust stability. A homotopy algorithm is presented which generates a trajectory of gains that may be implemented to determine maximum achievable performance for a given model error bound. Examples show that a better balance between robustness and performance is obtained using the mixed H2/H(infinity) design method than either H2 or mu-synthesis control design. A second contribution is a new procedure for closed-loop system identification which refines parameters of a control design model in a canonical realization. Examples demonstrate convergence of the parameter estimation and improved performance realized by using the refined model for controller redesign. These developments result in an effective mechanism for achieving high-performance control of flexible space structures.

  11. Research on Performance Prediction and Maintenance Strategy of Expressway Based on Fuzzy Optimum Theory

    Microsoft Academic Search

    Liu Lijun; Zhang Hui

    2010-01-01

    Pavement Preventive Maintenance (PPM)technologies is adopted to predict the performance of pavement and select effective strategies on the expressway, the method can enormously extends the service life of pavement and result in lower maintenance costs. This paper describes prediction of highway pavement performance by means of gray system theory, and the gradual solution, which leads to the optimal model, is

  12. Generation mechanisms of tire-pavement noise

    NASA Astrophysics Data System (ADS)

    Dare, Tyler P.

    Tire-pavement noise is the dominant source of traffic noise at highway speeds. It is the result of a combination of several noise generation mechanisms, including tire carcass vibration and tread block vibration. Because multiple mechanisms are involved, it is difficult to predict the effects of changes in pavement parameters on tire-pavement noise. In this research, a set of experimental techniques were developed to decompose a measured tire-pavement noise spectrum into a set of constituent spectra relating to each generation mechanism. Three principal mechanisms were identified: treadband vibration, sidewall vibration, and tangential tread block vibration. By combining the constituent spectra associated with these mechanisms, it was possible to accurately predict the total tire-pavement noise spectrum. The constituent spectra were fit to tire-pavement noise data measured on asphalt and concrete pavements at highway speeds. It was found that the constituent spectra fit the measured data well, and a two-parameter model was developed to predict tire-pavement noise levels from pavement texture data.

  13. Flexible and low-voltage integrated circuits constructed from high-performance nanocrystal transistors.

    PubMed

    Kim, David K; Lai, Yuming; Diroll, Benjamin T; Murray, Christopher B; Kagan, Cherie R

    2012-01-01

    Colloidal semiconductor nanocrystals are emerging as a new class of solution-processable materials for low-cost, flexible, thin-film electronics. Although these colloidal inks have been shown to form single, thin-film field-effect transistors with impressive characteristics, the use of multiple high-performance nanocrystal field-effect transistors in large-area integrated circuits has not been shown. This is needed to understand and demonstrate the applicability of these discrete nanocrystal field-effect transistors for advanced electronic technologies. Here we report solution-deposited nanocrystal integrated circuits, showing nanocrystal integrated circuit inverters, amplifiers and ring oscillators, constructed from high-performance, low-voltage, low-hysteresis CdSe nanocrystal field-effect transistors with electron mobilities of up to 22 cm(2) V(-1) s(-1), current modulation >10(6) and subthreshold swing of 0.28 V dec(-1). We fabricated the nanocrystal field-effect transistors and nanocrystal integrated circuits from colloidal inks on flexible plastic substrates and scaled the devices to operate at low voltages. We demonstrate that colloidal nanocrystal field-effect transistors can be used as building blocks to construct complex integrated circuits, promising a viable material for low-cost, flexible, large-area electronics. PMID:23169057

  14. The flexible Ca-test: An improved performance in a gas permeability measurement system

    NASA Astrophysics Data System (ADS)

    Song, Eun Ho; Park, Young Wook; Choi, Jin Hwan; Park, Tae Hyun; Jeong, Jin Wook; Choi, Hyun Ju; Ju, Byeong Kwon

    2011-05-01

    A flexible performance permeability measuring test for flexible organic light-emitting diodes is described in this paper. A single thin film layer of gas barriers is constructed on polyethersulfone (PES). The barrier coats the upper and lower surfaces of the PES layer. Two PES samples, one coated with Al2O3 on both surfaces and the other coated on a single surface, were made for comparison. According to this test, the time-dependent transmission curve of the one sided barrier sample had a linear slope which measured 1.65 g/m2/day at room temperature at a 50% relative humidity. This result shows that the measurement time is about 182% faster than has been achieved with the conventional test structure that uses a glass substrate. In addition, this measurement structure not only reduces the inevitable electrical noise which occurs during measurement but also increases the water vapor permeation signal. These effects improve the sensing reliability of the test. In addition, this structure is flexible, so one can instantly detect barrier performance changes when applying external stress.

  15. Vacancy associates-rich ultrathin nanosheets for high performance and flexible nonvolatile memory device.

    PubMed

    Liang, Lin; Li, Kun; Xiao, Chong; Fan, Shaojuan; Liu, Jiao; Zhang, Wenshuai; Xu, Wenhui; Tong, Wei; Liao, Jiaying; Zhou, Yingying; Ye, Bangjiao; Xie, Yi

    2015-03-01

    On the road of innovation in modern information technology, resistive switching random access memory (RRAM) has been considered to be the best potential candidate to replace the conventional Si-based technologies. In fact, the key prerequisite of high storage density and low power consumption as well as flexibility for the tangible next generation of nonvolatile memories has stimulated extensive research into RRAM. Herein, we highlight an inorganic graphene analogue, ultrathin WO3H2O nanosheets with only 2-3 nm thickness, as a promising material to construct a high performance and flexible RRAM device. The abundant vacancy associates in the ultrathin nanosheets, revealed by the positron annihilation spectra, act not only carrier reservoir to provide carriers but also capture center to trap the actived Cu(2+) for the formation of conductive filaments, which synergistically realize the resistive switching memory with low operating voltage (+1.0 V/-1.14 V) and large resistance ON/OFF ratio (>10(5)). This ultrathin-nanosheets-based RRAM device also shows long retention time (>10(5) s), good endurance (>5000 cycles), and excellent flexibility. The finding of the existence of distinct defects in ultrathin nanosheets undoubtedly leads to an atomic level deep understanding of the underlying nature of the resistive switching behavior, which may serve as a guide to improve the performances and promote the rapid development of RRAM. PMID:25668153

  16. Reinforcement of asphalt concrete pavement by segments of exhausted fiber used for sorption of oil spill

    NASA Astrophysics Data System (ADS)

    Lukashevich, V. N.; Efanov, I. N.

    2015-01-01

    The paper is aimed at construction of the experimental road pavement made of dispersed reinforced asphalt concrete. Electronic paramagnetic resonance, infrared spectroscopy and fluorescent bitumen studies were used to prove that disperse reinforcement of asphalt concrete mixtures with fibers of exhausted sorbents reduce the selective filtration of low polymeric fractions of petroleum bitumen and improve its properties in the adsorption layer. Sesquioxides are neutralized as catalysts aging asphalt binder. This leads to improvement in the elasticity of bitumen films at low temperatures and provide better crack resistance of coatings to reduce the intensity of the aging of asphalt binder, and, therefore, to increase the durability of road pavements. The experimental road pavement made of dispersed reinforced asphalt concrete operated during 4 years and demonstrated better transport- performance properties in comparison with the analogue pavements.

  17. Preliminary evaluation of the lifecycle costs and market barriers of reflective pavements

    SciTech Connect

    Ting, M.; Koomey, J.G.; Pomerantz, M.

    2001-11-21

    The objective of this study is to evaluate the life cycle costs and market barriers associated with using reflective paving materials in streets and parking lots as a way to reduce the urban heat island effect. We calculated and compared the life cycle costs of conventional asphalt concrete (AC) pavements to those of other existing pavement technologies with higher reflectivity-portland cement concrete (PCC), porous pavements, resin pavements, AC pavements using light-colored chip seals, and AC pavements using light-colored asphalt emulsion additives. We found that for streets and parking lots, PCC can provide a cost-effective alternative to conventional AC when severely damaged pavements must be completely reconstructed. We also found that rehabilitating damaged AC streets and intersections with thin overlays of PCC (ultra-thin white topping) can often provide a cost-effective alternative to standard rehabilitation techniques using conventional AC. Chip sealing is a common maintenance treatment for low-volume streets which, when applied using light-colored chips, could provide a reflective pavement surface. If the incremental cost of using light-colored chips is low, this chip sealing method could also be cost-effective, but the incremental costs of light-colored chips are as of yet uncertain and expected to vary. Porous pavements were found to have higher life cycle costs than conventional AC in parking lots, but several cost-saving features of porous pavements fell outside the boundaries of this study. Resin pavements were found to be only slightly more expensive than conventional AC, but the uncertainties in the cost and performance data were large. The use of light-colored additives in asphalt emulsion seal coats for parking lot pavements was found to be significantly more expensive than conventional AC, reflecting its current niche market of decorative applications. We also proposed two additional approaches to increasing the reflectivity of conventional AC, which we call the chipping and aggregate methods, and calculated their potential life cycle costs. By analyzing the potential for increased pavement durability resulting from these conceptual approaches, we then estimated the incremental costs that would allow them to be cost-effective compared to conventional AC. For our example case of Los Angeles, we found that those allowable incremental costs range from less than dollar 1 to more than dollar 11 per square yard (dollar 1 to dollar 13 per square meter) depending on street type and the condition of the original pavement. Finally, we evaluated the main actors in the pavement market and the existing and potential market barriers associated with reflective pavements. Apart from situations where lifecycle costs are high compared to conventional AC, all reflective paving technologies face a cultural barrier based on the belief that black is better. For PCC, high first costs were found to be the most significant economic barrier, particularly where agencies are cons trained by first cost. Lack of developer standards was found to be a significant institutional barrier to PCC since developers are often not held accountable for the long-term maintenance of roads after initial construction, which creates a misplaced incentive to build low first-cost pavements. PCC also faces site-specific barriers such as poorly compacted base soils and proximity to areas of frequent utility cutting.

  18. The use of reflective and permeable pavements as a potential practice for heat island mitigation and stormwater management

    NASA Astrophysics Data System (ADS)

    Li, H.; Harvey, J. T.; Holland, T. J.; Kayhanian, M.

    2013-03-01

    To help address the built environmental issues of both heat island and stormwater runoff, strategies that make pavements cooler and permeable have been investigated through measurements and modeling of a set of pavement test sections. The investigation included the hydraulic and thermal performance of the pavements. The permeability results showed that permeable interlocking concrete pavers have the highest permeability (or infiltration rate, 0.5 cm s-1). The two permeable asphalt pavements showed the lowest permeability, but still had an infiltration rate of 0.1 cm s-1, which is adequate to drain rainwater without generating surface runoff during most typical rain events in central California. An increase in albedo can significantly reduce the daytime high surface temperature in summer. Permeable pavements under wet conditions could give lower surface temperatures than impermeable pavements. The cooling effect highly depends on the availability of moisture near the surface layer and the evaporation rate. The peak cooling effect of watering for the test sections was approximately 15-35?C on the pavement surface temperature in the early afternoon during summer in central California. The evaporative cooling effect on the pavement surface temperature at 4:00 pm on the third day (25 h after watering) was still 2-7?C lower compared to that on the second day, without considering the higher air temperature on the third day. A separate and related simulation study performed by UCPRC showed that full depth permeable pavements, if designed properly, can carry both light-duty traffic and certain heavy-duty vehicles while retaining the runoff volume captured from an average California storm event. These preliminarily results indicated the technical feasibility of combined reflective and permeable pavements for addressing the built environment issues related to both heat island mitigation and stormwater runoff management.

  19. Study of flexible fin and compliant joint stiffness on propulsive performance: theory and experiments.

    PubMed

    Kancharala, A K; Philen, M K

    2014-09-01

    The caudal fin is a major source of thrust generation in fish locomotion. Along with the fin stiffness, the stiffness of the joint connecting the fish body to the tail plays a major role in the generation of thrust. This paper investigates the combined effect of fin and joint flexibility on propulsive performance using theoretical and experimental studies. For this study, fluid-structure interaction of the fin has been modeled using the 2D unsteady panel method coupled with nonlinear Euler-Bernoulli beam theory. The compliant joint has been modeled as a torsional spring at the leading edge of the fin. A comparison of self-propelled speed and efficiency with parameters such as heaving and pitching amplitude, oscillation frequency, flexibility of the fin and the compliant joint is reported. The model also predicts the optimized stiffnesses of the compliant joint and the fin for maximum efficiency. Experiments have been carried out to determine the effect of fin and joint stiffness on propulsive performance. Digital image correlation has been used to measure the deformation of the fins and the measured deformation is coupled with the hydrodynamic model to predict the performance. The predicted theoretical performance behavior closely matches the experimental values. PMID:24737004

  20. Graphene/carbon black hybrid film for flexible and high rate performance supercapacitor

    NASA Astrophysics Data System (ADS)

    Wang, Yaming; Chen, Junchen; Cao, Jianyun; Liu, Yan; Zhou, Yu; Ouyang, Jia-Hu; Jia, Dechang

    2014-12-01

    Reduced graphene oxide/carbon black (rGO/CB) hybrid films with different carbon black (CB) contents are prepared by a simple vacuum filtration method. The CB particles evenly distribute between the graphene layers, not only preventing the compact restack of rGO sheets but also providing electrical contact between the base planes of rGO sheets. As expected, the as-prepared rGO/CB hybrid film shows enhanced rate capability when compared with rGO film. Furthermore, a solid-state flexible supercapacitor has been constructed with the optimized rGO/CB hybrid film by using polyvinyl alcohol (PVA)/H2SO4 gel as electrolyte and Au coated PET film as current collector and mechanical support. The solid-state flexible supercapacitor shows a specific capacitance of 112Fg-1 at a scan rate of 5mVs-1, and excellent rate performance with a specific capacitance of 79.6Fg-1 at a high scan rate of 1Vs-1. Moreover, the flexible solid-state supercapacitor exhibits good cycling stability with capacitance retention of 94% after 3000 cycles in normal state plus 2000 cycles in bent state.

  1. High-performance flexible graphene aptasensor for mercury detection in mussels.

    PubMed

    An, Ji Hyun; Park, Seon Joo; Kwon, Oh Seok; Bae, Joonwon; Jang, Jyongsik

    2013-12-23

    Mercury (Hg) is highly toxic but has been widely used for numerous domestic applications, including thermometers and batteries, for decades, which has led to fatal outcomes due to its accumulation in the human body. Although many types of mercury sensors have been developed to protect the users from Hg, few methodologies exist to analyze Hg(2+) ions in low concentrations in real world samples. Herein, we describe the fabrication and characterization of liquid-ion gated field-effect transistor (FET)-type flexible graphene aptasensor with high sensitivity and selectivity for Hg. The field-induced responses from the graphene aptasensor had excellent sensing performance, and Hg(2+) ions with very low concentration of 10 pM could be detected, which is 2-3 orders of magnitude more sensitive than previously reported mercury sensors using electrochemical systems. Moreover, the aptasensor showed a highly specific response to Hg(2+) ions in mixed solutions. The flexible graphene aptasensor showed a very rapid response, providing a signal in less than 1 s when the Hg(2+) ion concentration was altered. Specificity to Hg(2+) ions was demonstrated in real world samples (in this case samples derived from mussels). The aptasensor was fabricated by transferring chemical vapor deposition (CVD)-grown graphene onto a transparent flexible substrate, and the structure displayed excellent mechanical durability and flexiblility. This graphene-based aptasensor has potential for detecting Hg exposure in human and in the environment. PMID:24279823

  2. High performance dual-wave mode flexible surface acoustic wave resonators for UV light sensing

    NASA Astrophysics Data System (ADS)

    He, X. L.; Zhou, J.; Wang, W. B.; Xuan, W. P.; Yang, X.; Jin, H.; Luo, J. K.

    2014-05-01

    Dual-mode flexible ZnO/polyimide surface acoustic wave (SAW)-based ultraviolet (UV) light sensors were fabricated and their performance was investigated. UV light sensing measurements showed that the responses of the dual wave modes of the sensors increase with the increase of light intensity and the frequency changes linearly with the change of light intensity. Under a 4.5 mW cm-2 UV light illumination, the resonant frequency of the Rayleigh wave decreased up to 43 kHz, while that of the Lamb wave was approximately 76 kHz. The UV light sensitivities for the two resonant modes are 111.3 and 55.8 ppm (mW cm-2)-1, respectively. The resonant frequency, phase angle and amplitude of the two resonant modes exhibited a good repeatability in responding to cyclic change of the UV light, and an excellent stability up to a long duration of UV light exposure. The dual-mode flexible SAW resonators are simple in structure, more accurate in detection, and can be fabricated at low cost are, therefore, very promising for application in flexible sensors and electronics.

  3. A systematic investigation of polymer binder flexibility on the electrode performance of lithium-ion batteries.

    PubMed

    Yuca, Neslihan; Zhao, Hui; Song, Xiangyun; Dogdu, Murat Ferhat; Yuan, Wen; Fu, Yanbao; Battaglia, Vincent S; Xiao, Xingcheng; Liu, Gao

    2014-10-01

    The mechanical failure at the electrode interfaces (laminate/current collector and binder/particle interfaces) leads to particle isolation and delamination, which has been regarded as one of the main reasons for the capacity decay and cell failure of lithium-ion batteries (LIBs). Polymer binder provides the key function for a good interface property and for maintaining the electrode integrity of LIBs. Triethylene glycol monomethyl ether (TEG) moieties were incorporated into polymethacrylic acid (PMAA) to different extents at the molecular level. Microscratch tests of the graphite electrodes based on these binders indicate that the electrode is more flexible with 5 or 10% TEG in the polymer binders. Crack generation is inhibited by the flexible TEG-containing binder, compared to that of the unmodified PMAA-based electrode, leading to the better cycling performance of the flexible electrode. With a 10% TEG moiety in the binder, the graphite half-cell reaches a reversible capacity of >270 mAh/g at the 1C rate, compared to a value of ?190 mAh/g for the unmodified PMAA binder. PMID:25203598

  4. Pervious Pavement System Evaluation-Paper

    EPA Science Inventory

    The use of a pervious pavement can be effective as a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete paver systems as a type of porous pavement. Although the pavers are impermeable, the spaces between the pave...

  5. Use of flexible plastic film isolators in performing potentially hazardous necropsies.

    PubMed Central

    Trexler, P C; Gilmour, A M

    1983-01-01

    A number of necropsies were performed with the body completely isolated in a flexible film isolator in order to determine the practicability of such a method in protecting the post mortem room staff from the risk of infection from the corpse. It is considered that necropsies can be carried out using such an isolator without hindrance to either manual skill or vision and that a high degree of safety is achieved. The isolator may also be used to carry out necropsies on decomposed bodies. Images PMID:6404948

  6. High performance and flexible FPGA-based time shared optical network (TSON) metro node.

    PubMed

    Yan, Yan; Zervas, Georgios; Qin, Yixuan; Rofoee, Bijan R; Simeonidou, Dimitra

    2013-03-11

    The paper presents the architecture, implementation and evaluation of the flexible and finely granular Time Shared Optical Network (TSON) metro node. It focuses on the FPGA-based Layer 2 TSON metro node system. The experimentally measured results show exceptional performance of up to 8.68 Gbps throughput per 10 Gbps port, 95.38% of theoretical maximum throughput, latency of less than 160 ?sec and jitter of less than 25 ?sec. The TSON topology agnostic node/network also delivers differentiated QoS latency levels yet always guaranteed (contention-free) by deploying diverse time-slice allocation schemes. PMID:23482121

  7. Greenhouse gas emissions of alternative pavement designs: framework development and illustrative application.

    PubMed

    Liu, Xiaoyu; Cui, Qingbin; Schwartz, Charles

    2014-01-01

    Pavement rehabilitation is carbon intensive and the choice of pavement type is a critical factor in controlling greenhouse gas (GHG) emissions. The existing body of knowledge is not able to support decision-making on pavement choice due to a lack of consensus on the system boundaries, the functional units and the estimation periods. Excessive data requirements further inhibit the generalization of the existing methodologies for design evaluation at the early planning stage. This study proposes a practical life-cycle GHG estimation approach, which is arguably effective to benchmark pavement emissions given project bid tabulation. A set of case studies conducted for this study suggest that recycled asphalt pavement (e.g., foam stabilized base (FSB), and warm mix asphalt (WMA)) would prevent up to 50% of GHGs from the initial construction phase. However, from a life-cycle perspective, pavement emissions are dictated largely by the traffic characteristics and the analysis period for the use phase. The benefits from using recycled materials (e.g., FSB) are likely to diminish if the recycled products do not perform as well as those properly proportioned with less recycled materials, or if the recycled materials are locally unavailable. When the AADT reaches 10,000, use phase releases more than 97% of the life cycle emissions and the emissions difference among alternative designs will be within 1%. PMID:24333742

  8. Recycling asphalt pavements. January 1975-January 1990 (a Bibliography from the COMPENDEX data base). Report for January 1975-January 1990

    SciTech Connect

    Not Available

    1990-03-01

    This bibliography contains citations concerning the recycling of asphalt-containing pavement materials. Articles include examples of recycling asphalt pavements; performance testing of recycled paving; methods including cold in-place, cold off-site, and hot-mix recycling; additives in recycled pavement for better performance; use of scrap roofing asphalt in conjunction with recycled paving; economics of recycling; process design; and process variables. Recycling of other materials is considered in related bibliographies. (Contains 130 citations fully indexed and including a title list.)

  9. Palladium-cobalt nanotube arrays supported on carbon fiber cloth as high-performance flexible electrocatalysts for ethanol oxidation.

    PubMed

    Wang, An-Liang; He, Xu-Jun; Lu, Xue-Feng; Xu, Han; Tong, Ye-Xiang; Li, Gao-Ren

    2015-03-16

    PdCo nanotube arrays (NTAs) supported on carbon fiber cloth (CFC) (PdCo NTAs/CFC) are presented as high-performance flexible electrocatalysts for ethanol oxidation. The fabricated flexible PdCo NTAs/CFC exhibits significantly improved electrocatalytic activity and durability compared with Pd NTAs/CFC and commercial Pd/C catalysts. Most importantly, the PdCo NTAs/CFC shows excellent flexibility and the high electrocatalytic performance remains almost constant under the different distorted states, such as normal, bending, and twisting states. This work shows the first example of Pd-based alloy NTAs supported on CFC as high-performance flexible electrocatalysts for ethanol oxidation. PMID:25631986

  10. Flexible nanocrystal-coated glass fibers for high-performance thermoelectric energy harvesting.

    PubMed

    Liang, Daxin; Yang, Haoran; Finefrock, Scott W; Wu, Yue

    2012-04-11

    Recent efforts on the development of nanostructured thermoelectric materials from nanowires (Boukai, A. I.; et al. Nature 2008, 451, (7175), 168-171; Hochbaum, A. I.; et al. Nature 2008, 451, (7175), 163-167) and nanocrystals (Kim, W.; et al. Phys. Rev. Lett. 2006, 96, (4), 045901; Poudel, B.; et al. Science 2008, 320, (5876), 634-638; Scheele, M.; et al. Adv. Funct. Mater. 2009, 19, (21), 3476-3483; Wang, R. Y.; et al. Nano Lett. 2008, 8, (8), 2283-2288) show the comparable or superior performance to the bulk crystals possessing the same chemical compositions because of the dramatically reduced thermal conductivity due to phonon scattering at nanoscale surface and interface. Up to date, the majority of the thermoelectric devices made from these inorganic nanostructures are fabricated into rigid configuration. The explorations of truly flexible composite-based flexible thermoelectric devices (See, K. C.; et al. Nano Lett. 2010, 10, (11), 4664-4667) have thus far achieved much less progress, which in principle could significantly benefit the conversion of waste heat into electricity or the solid-state cooling by applying the devices to any kind of objects with any kind of shapes. Here we report an example using a scalable solution-phase deposition method to coat thermoelectric nanocrystals onto the surface of flexible glass fibers. Our investigation of the thermoelectric properties yields high performance comparable to the state of the art from the bulk crystals and proof-of-concept demonstration also suggests the potential of wrapping the thermoelectric fibers on the industrial pipes to improve the energy efficiency. PMID:22409308

  11. Flexible Pillared Graphene-Paper Electrodes for High-Performance Electrochemical Supercapacitors

    SciTech Connect

    Wang, Gongkai; Sun, Xiang; Lu, Fengyuan; Sun, Hongtao; Yu, Mingpeng; Jiang, Weilin; Liu, Changsheng; Lian, Jie

    2012-02-09

    Flexible graphene paper (GP) pillared by carbon black (CB) nanoparticles using a simple vacuum filtration method is developed as a high-performance electrode material for supercapacitors. Through the introduction of CB nanoparticles as spacers, the self-restacking of graphene sheets during the filtration process is mitigated to a great extent. The pillared GP-based supercapacitors exhibit excellent electrochemical performances and cyclic stabilities compared with GP without the addition of CB nanoparticles. At a scan rate of 10 mV s?1, the specific capacitance of the pillared GP is 138 F g^?1 and 83.2 F g^?1 with negligible 3.85% and 4.35% capacitance degradation after 2000 cycles in aqueous and organic electrolytes, respectively. At an extremely fast scan rate of 500 mV s ^?1, the specific capacitance can reach 80 F g^?1 in aqueous electrolyte. No binder is needed for assembling the supercapacitor cells and the pillared GP itself may serve as a current collector due to its intrinsic high electrical conductivity. The pillared GP has great potential in the development of promising flexible and ultralight-weight supercapacitors for electrochemical energy storage.

  12. Full scale demonstration of air-purifying pavement.

    PubMed

    Ballari, M M; Brouwers, H J H

    2013-06-15

    Experiments concerning a full-scale demonstration of air purifying pavement in Hengelo, The Netherlands, are reported. The full width of the street was provided with concrete pavement containing TiO? over a length of 150 m ("DeNOx street"). Another part of the street, about 100 m, was paved with normal paving blocks ("Control street"). The outdoor monitoring was done during 26 days for a period exceeding one year, and measured parameters included traffic intensity, NO, NO? and ozone concentrations, temperature, relative humidity, wind speed and direction, and the visible and UV light irradiance. Prior and parallel to these field measurements, the used blocks were also measured in the lab to assess their performance. The NOx concentration was, on average, 19% (considering the whole day) and 28% (considering only afternoons) lower than the obtained values in the Control street. Under ideal weather conditions (high radiation and low relative humidity) a NOx concentration decrease of 45% could be observed. PMID:23731840

  13. Scalable fabrication of high-performance and flexible graphene strain sensors

    NASA Astrophysics Data System (ADS)

    Tian, He; Shu, Yi; Cui, Ya-Long; Mi, Wen-Tian; Yang, Yi; Xie, Dan; Ren, Tian-Ling

    2013-12-01

    Graphene strain sensors have promising prospects of applications in detecting human motion. However, the shortage of graphene growth and patterning techniques has become a challenging issue hindering the application of graphene strain sensors. Therefore, we propose wafer-scale flexible strain sensors with high-performance, which can be fabricated in one-step laser scribing. The graphene films could be obtained by directly reducing graphene oxide film in a Light-Scribe DVD burner. The gauge factor (GF) of the graphene strain sensor (10 mm 10 mm square) is 0.11. In order to enhance the GF further, graphene micro-ribbons (20 ?m width, 0.6 mm long) has been used as strain sensors, of which the GF is up to 9.49. The devices may conform to various application requirements, such as high GF for low-strain applications and low GF for high deformation applications. The work indicates that laser scribed flexible graphene strain sensors could be widely used in medical-sensing, bio-sensing, artificial skin and many other areas.Graphene strain sensors have promising prospects of applications in detecting human motion. However, the shortage of graphene growth and patterning techniques has become a challenging issue hindering the application of graphene strain sensors. Therefore, we propose wafer-scale flexible strain sensors with high-performance, which can be fabricated in one-step laser scribing. The graphene films could be obtained by directly reducing graphene oxide film in a Light-Scribe DVD burner. The gauge factor (GF) of the graphene strain sensor (10 mm 10 mm square) is 0.11. In order to enhance the GF further, graphene micro-ribbons (20 ?m width, 0.6 mm long) has been used as strain sensors, of which the GF is up to 9.49. The devices may conform to various application requirements, such as high GF for low-strain applications and low GF for high deformation applications. The work indicates that laser scribed flexible graphene strain sensors could be widely used in medical-sensing, bio-sensing, artificial skin and many other areas. Electronic supplementary information (ESI) available: Testing results and discussion of graphene strain sensors. See DOI: 10.1039/c3nr04521h

  14. Flexible Acculturation

    E-print Network

    Lee, Hsiang-Chieh

    2008-01-01

    it differs from many other terms that have been proposed in sociology, migration studies, and cultural studies. These principles include: flexible acculturation involves diverse social players so that it is different from the con - 51 Flexible..., such as the state, the nation, or other social groups (Jackson 2001). Even though multiple legal affiliations increase available resources to perform multicultural flexibilities, they are not a precondition. For instance, most taiwanese in china...

  15. Carbon nanotube bundles/polystyrene composites as high-performance flexible thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Suemori, Kouji; Watanabe, Yuichi; Hoshino, Satoshi

    2015-03-01

    Lightweight and flexible thermoelectric devices consisting of carbon nanotube (CNT)-based materials have the potential to be used for the various applications, such as energy harvesting from the low-temperature waste heat that exists ubiquitously in living areas. Because high-performance CNT-based materials are crucial for the broad-ranging employment of CNT-based thermoelectric devices, considerable efforts are being made to improve the power-generation capability of CNT-based thermoelectric materials. Here, we report high-performance thermoelectric composites consisting of CNT bundles and polystyrene fabricated by a planetary ball milling-based dispersion technique, which allows for the direct dispersion of the CNT bundles within the polystyrene matrix without causing the disaggregation of the bundled CNTs into individual ones. The CNT-bundles/polystyrene composites reported here exhibit a power factor of 413 ?W/K2.m.

  16. Ultrafast laser trimming for reduced device leakage in high performance OTFT semiconductors for flexible displays

    NASA Astrophysics Data System (ADS)

    Karnakis, Dimitris; Cooke, Michael D.; Chan, Y. F.; Ogier, Simon D.

    2013-03-01

    Organic semiconductors (OSC) are solution processable synthetic materials with high carrier mobility that promise to revolutionise flexible electronics manufacturing due to their low cost, lightweight and high volume low temperature printing in reel-to-reel (R2R) [1] for applications such as flexible display backplanes (Fig.1), RFID tags, and logic/memory devices. Despite several recent technological advances, organic thin film transistor (OTFT) printing is still not production-ready due to limitations mainly with printing resolution on dimensionally unstable substrates and device leakage that reduces dramatically electrical performance. OTFTs have the source-drain in ohmic contact with the OSC material to lower contact resistance. If they are unpatterned, a leakage pathway from source to drain develops which results in non-optimum on/off currents and not controllable device uniformity (Fig.2). DPSS lasers offer several key advantages for OTFT patterning including maskless, non-contact, dry patterning, scalable large area operation with precision registration, well-suited to R2R manufacturing at overall ?m size resolutions. But the thermal management of laser processing is very important as the devices are very sensitive to heat and thermomechanical damage [2]. This paper discusses 343nm picosecond laser ablation trimming of 50nm thick PTAA, TIPS pentacene and other semiconductor compounds on thin 50nm thick metal gold electrodes in a top gate configuration. It is shown that with careful optimisation, a suitable process window exists resulting in clean laser structuring without damage to the underlying layers while also containing laser debris. Several order of magnitude improvements were recorded in on/off currents up to 106 with OSC mobilities of 1 cm2/Vsec, albeit at slightly higher than optimum threshold voltages which support demanding flexible display backplane applications.

  17. An evaluation of pavement markings and raised pavement markers at left exit lane drops

    E-print Network

    Lance, Marty Tina

    1994-01-01

    AN EVALUATION OF PAVEMENT MARKINGS AND RAISED PAVEMENT MARKERS AT LEFT EXIT LANE DROPS A Thesis by MARTY TINA LANCE Submitted to Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved... Markings and Raised Pavement Markers at Left Exit Lane Drops. (August 1994) Marty Tina Lance, B. S. , Lander University; B. S. , Clemson University Chair of Advisory Cominittee: Dr. Thomas Urbanik II Most highway engineers agree that freeway exit lane...

  18. High-performance logic circuits using solution-based, low-temperature semiconductors for flexible electronics

    NASA Astrophysics Data System (ADS)

    Mejia, Israel; Salas-Villasenor, Ana L.; Murphy, John W.; Kunnen, George R.; Cantley, Kurtis D.; Allee, David R.; Gnade, Bruce E.; Quevedo-Lopez, Manuel A.

    2013-05-01

    In this work we demonstrate high performance and low-power n-type inverters using solution-based CdS as the semiconductor in thin film transistors. Our fabrication process consists of five mask levels and a maximum temperature of 150 C. The CdS is deposited using chemical bath deposition at 70 C to provide full compatibility with flexible substrates. Isolated TFTs showed mobilities up to 10 cm2/V-s and threshold voltages of approximately 0.5V. Inverters were biased at 1, 3 and 5 V, resulting in maximum gains in the range of 60 at VDD = 3V. The devices and circuits are fully patterned using standard photolithographic techniques that can be used to design more complex circuitry for flexible and large area electronic applications. In addition we used an extraction parameter method for our TFTs that allows the use of regular SPICE simulation software to design and test the circuits. Our simulations are in good agreement with the experimental data for isolated devices and inverters. Other circuits such as NAND gates are also demonstrated.

  19. High performance low temperature carbon composite catalysts for flexible dye sensitized solar cells.

    PubMed

    Hashmi, Syed Ghufran; Halme, Janne; Saukkonen, Tapio; Rautama, Eeva-Leena; Lund, Peter

    2013-10-28

    Roll-to-roll manufacturing of dye sensitized solar cells (DSSCs) requires efficient and low cost materials that adhere well on the flexible substrates used. In this regard, different low temperature carbon composite counter electrode (CE) catalyst ink formulations for flexible DSSCs were developed that can be simply and quickly coated on plastic substrates and dried below 150 C. The CEs were investigated in terms of photovoltaic performance in DSSCs by current-voltage measurements, mechanical adhesion properties by bending and tape tests, electro-catalytic performance by electrochemical impedance spectroscopy and microstructure by electron microscopy. In the bending and tape tests, PEDOT-carbon composite catalyst layers exhibited higher elasticity and better adhesion on all the studied substrates (ITO-PET and ITO-PEN plastic, and FTO-glass), compared to a binder free carbon composite and a TiO2 binder enriched carbon composite, and showed lower charge transfer resistance (1.5-3 ? cm(2)) than the traditional thermally platinized CE (5 ? cm(2)), demonstrating better catalytic performance for the tri-iodide reduction reaction. Also the TiO2 binder enriched carbon composite showed good catalytic characteristics and relatively good adhesion on ITO-PET, but on ITO-PEN its adhesion was poor. A DSSC with the TiO2 binder enriched catalyst layer reached 85% of the solar energy conversion efficiency of the reference DSSC based on the traditional thermally platinized CE. Based on the aforementioned characteristics, these carbon composites are promising candidates for replacing the platinum catalyst in a high volume roll-to-roll manufacturing process of DSSCs. PMID:24042582

  20. Final Technical Report, Oct 2004 - Nov. 2006, High Performance Flexible Reversible Solid Oxide Fuel Cell

    SciTech Connect

    Guan, Jie; Minh, Nguyen

    2007-02-21

    This report summarizes the work performed for the program entitled High Performance Flexible Reversible Solid Oxide Fuel Cell under Cooperative Agreement DE-FC36-04GO14351 for the U. S. Department of Energy. The overall objective of this project is to demonstrate a single modular stack that generates electricity from a variety of fuels (hydrogen and other fuels such as biomass, distributed natural gas, etc.) and when operated in the reverse mode, produces hydrogen from steam. This project has evaluated and selected baseline cell materials, developed a set of materials for oxygen and hydrogen electrodes, and optimized electrode microstructures for reversible solid oxide fuel cells (RSOFCs); and demonstrated the feasibility and operation of a RSOFC multi-cell stack. A 10-cell reversible SOFC stack was operated over 1000 hours alternating between fuel cell (with hydrogen and methane as fuel) and steam electrolysis modes. The stack ran very successfully with high power density of 480 mW/cm2 at 0.7V and 80% fuel utilization in fuel cell mode and >6 SLPM hydrogen production in steam electrolysis mode using about 1.1 kW electrical power. The hydrogen generation is equivalent to a specific capability of 2.59 Nm3/m2 with electrical energy demand of 3 kWh/Nm3. The performance stability in electrolysis mode was improved vastly during the program with a degradation rate reduction from 8000 to 200 mohm-cm2/1000 hrs. This was accomplished by increasing the activity and improving microstructure of the oxygen electrode. Both cost estimate and technology assessment were conducted. Besides the flexibility running under both fuel cell mode and electrolysis mode, the reversible SOFC system has the potentials for low cost and high efficient hydrogen production through steam electrolysis. The cost for hydrogen production at large scale was estimated at ~$2.7/kg H2, comparing favorably with other electrolysis techology.

  1. Improvements to a Transport Model of Asphalt Binder Oxidation in Pavements: Pavement Temperature Modeling, Oxygen Diffusivity in Asphalt Binders and Mastics, and Pavement Air Void Characterization

    E-print Network

    Han, Rongbin

    2012-07-16

    in asphalt binders and mastics, and characterizing air voids in pavements, these key model elements were studied in turn. Hourly pavement temperatures were calculated with an improved one-dimensional heat transfer model, coupled with methods to obtain model...

  2. Can We Build a Truly High Performance Computer Which is Flexible and Transparent?

    PubMed Central

    Rojas, Jhonathan P.; Torres Sevilla, Galo A.; Hussain, Muhammad M.

    2013-01-01

    State-of-the art computers need high performance transistors, which consume ultra-low power resulting in longer battery lifetime. Billions of transistors are integrated neatly using matured silicon fabrication process to maintain the performance per cost advantage. In that context, low-cost mono-crystalline bulk silicon (100) based high performance transistors are considered as the heart of today's computers. One limitation is silicon's rigidity and brittleness. Here we show a generic batch process to convert high performance silicon electronics into flexible and semi-transparent one while retaining its performance, process compatibility, integration density and cost. We demonstrate high-k/metal gate stack based p-type metal oxide semiconductor field effect transistors on 4 inch silicon fabric released from bulk silicon (100) wafers with sub-threshold swing of 80?mV dec?1 and on/off ratio of near 104 within 10% device uniformity with a minimum bending radius of 5?mm and an average transmittance of ~7% in the visible spectrum. PMID:24018904

  3. A flexible multi-stimuli in situ (S)TEM: Concept, optical performance, and outlook.

    PubMed

    Brrnert, Felix; Mller, Heiko; Riedel, Thomas; Linck, Martin; Kirkland, Angus I; Haider, Max; Bchner, Bernd; Lichte, Hannes

    2015-04-01

    The progress in (scanning) transmission electron microscopy development had led to an unprecedented knowledge of the microscopic structure of functional materials at the atomic level. Additionally, although not widely used yet, electron holography is capable to map the electric and magnetic potential distributions at the sub-nanometer scale. Nevertheless, in situ studies inside a (scanning) transmission electron microscope ((S)TEM) are extremely challenging because of the much restricted size and accessibility of the sample space. Here, we introduce a concept for a dedicated in situ (S)TEM with a large sample chamber for flexible multi-stimuli experimental setups and report about the electron optical performance of the instrument. We demonstrate a maximum resolving power of about 1nm in conventional imaging mode and substantially better than 5nm in scanning mode while providing an effectively usable "pole piece gap" of 70mm. PMID:25624019

  4. Coupling flexible solar cell with parabolic trough solar-concentrator-prototype design and performance

    NASA Astrophysics Data System (ADS)

    Panin, Alexander; Bergquist, Jonathon

    2007-10-01

    Solar cells are still too expensive (5-20/watt) to compete with traditional fossil fuel power generating methods (1/watt). Parabolic trough solar concentrator has the advantage of modest concentration ratio (10-100) which is well suited for coupling with solar cell. Thus using small area solar cell placed in the focal line of parabolic trough may be economically viable alternative to flat solar panels. We experiment with flexible solar cell (backed by water cooling pipe) placed in the focus of parabolic trough reflector. Another advantage of parabolic trough concentrator is very relaxed tracking requirement. For example, east-west oriented concentrator (aligned with the ecliptic plane) does not even need any tracking during core 4-6 hours around noon (when maximum illumination is available). The design and the performance of the prototype, as well as possible economical benefits of full scale projects are discussed in the presentation.

  5. Characterizing performances of solder paste printing process at flexible manufacturing lines

    NASA Astrophysics Data System (ADS)

    Siew, Jit Ping; Low, Heng Chin; Teoh, Ping Chow

    2015-02-01

    Solder paste printing (SPP) has been a challenge on printed circuit board (PCB) manufacturing, evident by the proliferation of solder paste inspection equipment, or substituted by rigorous non-value added activity of manual inspections. The objective of this study is to characterize the SPP performance of various products manufactured in flexible production lines with different equipment configurations, and determine areas for process improvement. The study began by collecting information on SPP performance relative to component placement (CP) process, and to the proportion of mixed products. Using a clustering algorithm to group similar elements together, SPP performance across all product-production line pairs are statistically modeled to discover the trend and the influential factors. The main findings are: (a) Ratio of overall dpku for CP and SPP processes are 2:1; (b) logistic regression models of SPP performance indicated that only effects of product-production line and solder paste printer configuration are significant; (c) PCB circuitry design with BGA components and single solder paste printer line configurations generated the highest monthly defects, with the highest variation in the latter.

  6. Loads and propulsive efficiency of a flexible airfoil performing sinusoidal deformations

    NASA Astrophysics Data System (ADS)

    Ulrich, Xialing; Peters, David

    2014-02-01

    This paper presents the application of state-space airloads theory to a flexible airfoil performing sinusoidal deformations at high Reynolds numbers. Given the two-dimensional motion of a flexible airfoil, we derived the closed forms for the propulsive force, lift force, generalized forces of pitching and bending as functions of reduced frequency k, dimensionless wavelength z, and dimensionless amplitude A/(2b). We also calculate the power required to perform this sinusoidal deformation and the propulsive efficiency. Our results show a positive, time-averaged propulsive force for all k>k0=?/z, which is when the wave speed is greater than the moving speed. At k=k0, which is when the moving speed reaches the wave speed, the motion reaches a steady-state with all forces being zero. When k

  7. Pervious Pavement System Evaluation- Abstract 1

    EPA Science Inventory

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, gra...

  8. Permeable Pavement Research - Edison, New Jersey

    EPA Science Inventory

    This presentation provides the background and summary of results collected at the permeable pavement parking lot monitored at the EPA facility in Edison, NJ. This parking lot is surfaced with permeable interlocking concrete pavers (PICP), pervious concrete, and porous asphalt. ...

  9. Acute whole body vibration training increases vertical jump and flexibility performance in elite female field hockey players

    PubMed Central

    Cochrane, D; Stannard, S

    2005-01-01

    Objective: To quantify the acute effect of whole body vibration (WBV) training on arm countermovement vertical jump (ACMVJ), grip strength, and flexibility performance. Methods: Eighteen female elite field hockey players each completed three interventions of WBV, control, and cycling in a balanced random manner. WBV was performed on a Galileo machine (26 Hz) with six different exercises being performed. For the control, the same six exercises were performed at 0 Hz, whilst cycling was performed at 50 W. Each intervention was 5 min in duration with ACMVJ, grip strength, and flexibility measurements being conducted pre and post intervention. Results: There was a positive interaction effect (interventionxpre-post) of enhanced ACMVJ (p<0.001) and flexibility (p<0.05) parameters following WBV; however no changes were observed after the control and cycling interventions. There was no interaction effect for grip strength following the three interventions. Conclusions: Acute WBV causes neural potentiation of the stretch reflex loop as shown by the improved ACMVJ and flexibility performance. Additionally, muscle groups less proportionally exposed to vibration do not exhibit physiological changes that potentiate muscular performance. PMID:16244199

  10. Reducing traffic noise with quieter pavements

    NASA Astrophysics Data System (ADS)

    Donavan, Paul

    2005-09-01

    In recent years, interest has increased in the use of pavement type to reduce traffic noise. This has been driven by public concern over noise from freeways and state transportation agencies' interest in using pavement instead of sound walls to mitigate traffic noise. Beginnings of the recent interest go back to 1998 with the formation of the Institute for Safe, Quiet & Durable Highways at Purdue University and the initiation long-term research by the California Department of Transportation (Caltrans) on the effectiveness of quieter pavements. In 2002, the State of Arizona announced plans to overlay 115 miles of concrete freeway in the greater Phoenix area with a quieter asphalt rubber surface. This turned into the first Quiet Pavement Pilot Program in partnership between Federal Highway Administration (FHWA) and the Arizona Department of Transportation. Since that time, the FHWA in cooperation with the American Association of State Highway Transportation Agencies conducted a fact finding ``Scan'' tour in Europe to evaluate their quiet pavement technology and policy. This was followed by the first comparative tire/pavement noise testing in the US and Europe using the same procedures and test tires. The results, issues, and future directions surrounding these activities will be discussed.

  11. Fusing complementary images for pavement cracking measurements

    NASA Astrophysics Data System (ADS)

    Yao, Ming; Zhao, Zuyun; Yao, Xun; Xu, Bugao

    2015-02-01

    Cracking is a major pavement distress that jeopardizes road serviceability and traffic safety. Automated pavement distress survey (APDS) systems have been developed using digital imaging technology to replace human surveys for more timely and accurate inspections. Most APDS systems require special lighting devices to illuminate pavements and prevent shadows of roadside objects that distort cracks in the image. Most artificial lighting devices are laser based, and are either hazardous to unprotected people or require dedicated power supplies on the vehicle. This study was aimed to develop a new imaging system that can scan pavement surface at highway speed and determine the level of severity of pavement cracking without using any artificial lighting. The new system consists of dual line-scan cameras that are installed side by side to scan the same pavement area as the vehicle moves. Cameras are controlled with different exposure settings so that both sunlit and shadowed areas can be visible in two separate images. The paired images contain complementary details useful for reconstructing an image in which the shadows are eliminated. This paper intends to present (1) the design of the dual line-scan camera system, (2) a new calibration method for line-scan cameras to rectify and register paired images, (3) a customized image-fusion algorithm that merges the multi-exposure images into one shadow-free image for crack detection, and (4) the results of the field tests on a selected road over a long period.

  12. Lithium-doped zinc oxide nanowires-polymer composite for high performance flexible piezoelectric nanogenerator.

    PubMed

    Shin, Sung-Ho; Kim, Young-Hwan; Lee, Min Hyung; Jung, Joo-Yun; Seol, Jae Hun; Nah, Junghyo

    2014-10-28

    We present a method to develop high performance flexible piezoelectric nanogenerators (NGs) by employing Li-doped ZnO nanowires (NWs). We synthesized Li-doped ZnO NWs and adopted them to replace intrinsic ZnO NWs with a relatively low piezoelectric coefficient. When we exploited the ferroelectric phase transition induced in Li-doped ZnO NWs, the performance of the NGs was significantly improved and the NG fabrication process was greatly simplified. In addition, our approach can be easily expanded for large-scale NG fabrication. Consequently, the NGs fabricated by our simple method exhibit the excelling output voltage and current, which are stable and reproducible during periodic bending/releasing measurement over extended cycles. In addition, output voltage and current up to ? 180 V and ? 50 ?A, respectively, were obtained in the large-scale NG. The approach introduced here extends the performance limits of ZnO-based NGs and their potentials in practical applications. PMID:25265473

  13. Enhanced thermoelectric performance of PEDOT:PSS flexible bulky papers by treatment with secondary dopants.

    PubMed

    Mengistie, Desalegn A; Chen, Chang-Hsiao; Boopathi, Karunakara M; Pranoto, Ferry W; Li, Lain-Jong; Chu, Chih-Wei

    2015-01-14

    For inorganic thermoelectric materials, Seebeck coefficient and electrical conductivity are interdependent, and hence optimization of thermoelectric performance is challenging. In this work we show that thermoelectric performance of PEDOT:PSS can be enhanced by greatly improving its electrical conductivity in contrast to inorganic thermoelectric materials. Free-standing flexible and smooth PEDOT:PSS bulky papers were prepared using vacuum-assisted filtration. The electrical conductivity was enhanced to 640, 800, 1300, and 1900 S cm(-1) by treating PEDOT:PSS with ethylene glycol, polyethylene glycol, methanol, and formic acid, respectively. The Seebeck coefficient did not show significant variation with the tremendous conductivity enhancement being 21.4 and 20.6 ?V K(-1) for ethylene glycol- and formic acid-treated papers, respectively. This is because secondary dopants, which increase electrical conductivity, do not change oxidation level of PEDOT. A maximum power factor of 80.6 ?W m(-1) K(-2) was shown for formic acid-treated samples, while it was only 29.3 ?W m(-1) K(-2) for ethylene glycol treatment. Coupled with intrinsically low thermal conductivity of PEDOT:PSS, ZT ? 0.32 was measured at room temperature using Harman method. We investigated the reasons behind the greatly enhanced thermoelectric performance. PMID:25475257

  14. Parametric study of the swimming performance of a fish robot propelled by a flexible caudal fin.

    PubMed

    Low, K H; Chong, C W

    2010-12-01

    In this paper, we aim to study the swimming performance of fish robots by using a statistical approach. A fish robot employing a carangiform swimming mode had been used as an experimental platform for the performance study. The experiments conducted aim to investigate the effect of various design parameters on the thrust capability of the fish robot with a flexible caudal fin. The controllable parameters associated with the fin include frequency, amplitude of oscillation, aspect ratio and the rigidity of the caudal fin. The significance of these parameters was determined in the first set of experiments by using a statistical approach. A more detailed parametric experimental study was then conducted with only those significant parameters. As a result, the parametric study could be completed with a reduced number of experiments and time spent. With the obtained experimental result, we were able to understand the relationship between various parameters and a possible adjustment of parameters to obtain a higher thrust. The proposed statistical method for experimentation provides an objective and thorough analysis of the effects of individual or combinations of parameters on the swimming performance. Such an efficient experimental design helps to optimize the process and determine factors that influence variability. PMID:21068469

  15. The role of urban surfaces (permeable pavements) in regulating drainage and evaporation: development of a laboratory simulation experiment

    Microsoft Academic Search

    C. T. Andersen; I. D. L. Foster; C. J. Pratt

    1999-01-01

    Abstract: Permeable pavements and similar stormwater control devices have not been exploited in the UK, in part because their adoption,has been hindered,by a lack of detailed knowledge,of their hydrological performance. This paper describes a research programme,that produced,detailed information,on the hydrological behaviour of a car park surface. The study involved the construction,of full-scale permeable,pavement,model,car park structures and a rainfall simulator for

  16. Thermal Stability Analysis under Embankment with Asphalt Pavement and Cement Pavement in Permafrost Regions

    PubMed Central

    Jinping, Li; Xiaojuan, Quan

    2013-01-01

    The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8?m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results. PMID:24027444

  17. Thermal stability analysis under embankment with asphalt pavement and cement pavement in permafrost regions.

    PubMed

    Junwei, Zhang; Jinping, Li; Xiaojuan, Quan

    2013-01-01

    The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8?m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results. PMID:24027444

  18. High-performance carbon nanotube thin-film transistors on flexible paper substrates

    NASA Astrophysics Data System (ADS)

    Liu, Na; Yun, Ki Nam; Yu, Hyun-Yong; Shim, Joon Hyung; Lee, Cheol Jin

    2015-03-01

    Single-walled carbon nanotubes (SWCNTs) are promising materials as active channels for flexible transistors owing to their excellent electrical and mechanical properties. However, flexible SWCNT transistors have never been realized on paper substrates, which are widely used, inexpensive, and recyclable. In this study, we fabricated SWCNT thin-film transistors on photo paper substrates. The devices exhibited a high on/off current ratio of more than 106 and a field-effect mobility of approximately 3 cm2/V.s. The proof-of-concept demonstration indicates that SWCNT transistors on flexible paper substrates could be applied as low-cost and recyclable flexible electronics.

  19. Anionic polymer electrolyte with enhanced electrochemical performance based on surface-charged latex nanoparticles for flexible lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Ma, Xianguo; Huang, Xinglan; Gao, Jiandong; Zhang, Shu; Peng, Zuling; Deng, Zhenghua; Suo, Jishuan

    2014-12-01

    In the present paper, an anionic polymer electrolyte (APE) is facilely prepared using the surface-charged latex nanoparticles as the building blocks for the flexible lithium-ion batteries. Driven by the self-assembly of surface-charged latex, the APE demonstrates nanoporous structure, which provides continuous pathway for lithium conduction. The anionic polymer membrane exhibits mechanical flexibility before and after swollen with liquid electrolyte. Performance benefits of the anionic polymer membrane, as compared to commercialized polyethylene (PE) separator, are elucidated in terms of thermal shrinkage, liquid electrolyte wettability, mechanical bendability and open circuit voltage (OCV). Based on comprehensive characterization of the anionic polymer membrane/electrolyte characteristics, feasibility of applying the APE to electrolytes for flexible lithium-ion batteries is explored. The well-developed ion-conductive channel of the APE, in conjunction with stability of the surface-charged nanoparticles during cycling, plays a crucial role in providing excellent in cell performance.

  20. A modified analytical model to study the sensing performance of a flexible capacitive tactile sensor array

    NASA Astrophysics Data System (ADS)

    Liang, Guanhao; Wang, Yancheng; Mei, Deqing; Xi, Kailun; Chen, Zichen

    2015-03-01

    This paper presents a modified analytical model to study the sensing performance of a flexible capacitive tactile sensor array, which utilizes solid polydimethylsiloxane (PDMS) film as the dielectric layer. To predict the deformation of the sensing unit and capacitance changes, each sensing unit is simplified into a three-layer plate structure and divided into central, edge and corner regions. The plate structure and the three regions are studied by the general and modified models, respectively. For experimental validation, the capacitive tactile sensor array with 8? ?8 (= 64) sensing units is fabricated. Experiments are conducted by measuring the capacitance changes versus applied external forces and compared with the general and modified models predictions. For the developed tactile sensor array, the sensitivity predicted by the modified analytical model is 1.25%/N, only 0.8% discrepancy from the experimental measurement. Results demonstrate that the modified analytical model can accurately predict the sensing performance of the sensor array and could be utilized for model-based optimal capacitive tactile sensor array design.

  1. A Flexible, High Performance Service-Oriented Architecture for Detecting Cyber Attacks

    SciTech Connect

    Wynne, Adam S.; Gorton, Ian; Almquist, Justin P.; Chatterton, Jack; Thurman, David A.

    2008-02-01

    The next generation of intrusion detection and cyber defense technologies must be highly flexible so that deployed solutions can be quickly modified to detect new attack scenarios. They must also be able to provide the performance necessary to monitor traffic from high speed networks, and scale to enterprise wide deployments. In this paper we describe our experiences in creating a production application for cyber situational awareness. The application exploits the capabilities of several independently developed components and integrates them using SIFT (Scalable Information Fusion and Triage), a service-oriented architecture (SOA) designed for creating domain-independent, enterprise scale analytical applications. SIFT exploits a common design pattern for composing analytical components, and extends an existing messaging platform with scaling capabilities. We describe the design of the application, and provide a performance analysis that demonstrates the capabilities of the SIFT platform. The paper concludes by discussing the lessons we have learned from this project, and outlines the architecture of the MeDICI, the next generation of our enterprise analytics platforms.

  2. High-performance flexible photodetectors based on GaTe nanosheets.

    PubMed

    Wang, Zhenxing; Safdar, Muhammad; Mirza, Misbah; Xu, Kai; Wang, Qisheng; Huang, Yun; Wang, Fengmei; Zhan, Xueying; He, Jun

    2015-04-01

    2D layered GaTe materials have attracted a great deal of attention for optoelectronic applications due to their direct band structure, whether in bulk or as a single layer. In this paper, for the first time, we have synthesized high quality, single crystalline GaTe nanosheets by employing a facile CVD method. The size of the GaTe nanosheets reached several tens of micrometers, and some of them even exceeded 100 ?m. In particular, planar GaTe nanosheets were achieved on a mica substrate following a van der Waals epitaxial growth mechanism. Further, through a systematic comparison of the performances under various conditions, we found that adsorbates on the GaTe surface under ambient conditions strongly deteriorated the GaTe photodetector device performance. After removing the adsorbates in a ?7 10(-5) torr vacuum, a flexible, fast response GaTe photodetector with a high photoresponse, high mechanical stability and an excellent linear input-output relationship was obtained. The results presented in this study suggest that the GaTe nanosheets grown by a CVD method are promising candidates for optoelectronic applications in the future. PMID:25811647

  3. Printable nanostructured silicon solar cells for high-performance, large-area flexible photovoltaics.

    PubMed

    Lee, Sung-Min; Biswas, Roshni; Li, Weigu; Kang, Dongseok; Chan, Lesley; Yoon, Jongseung

    2014-10-28

    Nanostructured forms of crystalline silicon represent an attractive materials building block for photovoltaics due to their potential benefits to significantly reduce the consumption of active materials, relax the requirement of materials purity for high performance, and hence achieve greatly improved levelized cost of energy. Despite successful demonstrations for their concepts over the past decade, however, the practical application of nanostructured silicon solar cells for large-scale implementation has been hampered by many existing challenges associated with the consumption of the entire wafer or expensive source materials, difficulties to precisely control materials properties and doping characteristics, or restrictions on substrate materials and scalability. Here we present a highly integrable materials platform of nanostructured silicon solar cells that can overcome these limitations. Ultrathin silicon solar microcells integrated with engineered photonic nanostructures are fabricated directly from wafer-based source materials in configurations that can lower the materials cost and can be compatible with deterministic assembly procedures to allow programmable, large-scale distribution, unlimited choices of module substrates, as well as lightweight, mechanically compliant constructions. Systematic studies on optical and electrical properties, photovoltaic performance in experiments, as well as numerical modeling elucidate important design rules for nanoscale photon management with ultrathin, nanostructured silicon solar cells and their interconnected, mechanically flexible modules, where we demonstrate 12.4% solar-to-electric energy conversion efficiency for printed ultrathin (? 8 ?m) nanostructured silicon solar cells when configured with near-optimal designs of rear-surface nanoposts, antireflection coating, and back-surface reflector. PMID:25272244

  4. Assessing Green Infrastructure Performance Using Remote Hydologic Monitoring Measures

    EPA Science Inventory

    Two locations in Cincinnati were instrumented with level sensing technologies to measure stormwater flow in porous pavement and bioretention areas. Results indicate good performance of porous pavement and a cost effective application of technology to measure those flows. Result...

  5. RESEARCH Open Access Pavement crack characteristic detection based

    E-print Network

    Joensuu, University of

    are not caused by pavement distress such as tire marks, oil spills and shadows. In the field of 3D pavement crack distress such as tire marks, oil spills, shadows, and recent fillings [11]. Moreover, the shadows and poor

  6. Exploration of Pavement Oxidation Model Applications and Field Validation

    E-print Network

    Cui, Yuanchen

    2014-08-11

    oxidation have been investigated, such as oxidation kinetics, asphalt hardening in response to oxidation, pavement design, and environmental conditions. Based on understandings on those elements, pavement oxidation models have been developed to predict...

  7. MANUAL FOR WEB-BASED TXDOT RIGID PAVEMENT Sureel Saraf

    E-print Network

    Texas at Austin, University of

    NOT INTENDED FOR CONSTRUCTION, BIDDING, OR PERMIT PURPOSES. Research Supervisor: Moon Won #12;#12;Web evaluation of portland cement concrete (PCC) pavement. For example, in the mechanistic-empirical pavement

  8. Early age delamination in concrete pavements made with gravel aggregates

    E-print Network

    Liu, Juanyu

    2009-06-02

    Gravel aggregates had been used extensively in the Houston District of Texas Department of Transportation (TxDOT) for continuously reinforced concrete pavements construction for many years. However, some of these pavements have been subject to early...

  9. POROUS PAVEMENT. PHASE I. DESIGN AND OPERATIONAL CRITERIA

    EPA Science Inventory

    Design and operational criteria, utilization concepts, benefits and disadvantages, as well as other characteristics of porous pavements are presented in this report. Particular emphasis is placed on porous asphalt pavements, but the criteria and design approach are applicable to ...

  10. Investigation of antenna frequency impact on assessing voids of asphalt pavements using GPR

    NASA Astrophysics Data System (ADS)

    Plati, C.; Georgouli, K.; Loizos, A.

    2012-04-01

    Ground Penetrating Radar (GPR) is a Non Destructive Testing (NDT) technique that has been developed and improved upon over the past 30 years. The technique is frequently utilized in order to evaluate and assess pavement structures. GPR, for pavement evaluation purposes, can be described as a remote sensing system that emits a short pulse, of electromagnetic energy, into the pavement, with a central frequency varying from 10 MHz up to 2.5GHz. The two most commonly utilized setups are air-coupled and ground-coupled antenna systems. For air-coupled systems, the antennas are suspended above the pavement surface and can operate at normal traffic speeds (up to ~ 80 Km/h). The major drawback of the air-coupled antenna is that penetration depth is limited. On the other hand, for ground-coupled systems the antennas are in direct contact with the pavement surface, providing for better signal penetration into the pavement structure; however ground coupled systems can achieve only limited operational speeds. As a generalized rule, increasing the GPR central operating frequency, increases the investigation resolution, while decreasing the overall depth of investigation In the light of the above, air-coupled systems have become increasingly popular for the evaluation of the part of the pavement structure, especially for the asphalt layers, while ground-coupled systems are utilized mostly in order to gather information from the entire pavement structure (up to ~ 3 m depth). The majority of GPR pavement studies are carried out with air-coupled horn antennas, as they can be implemented at driving speeds without need for road closures. For instance, the 1 GHz air-coupled horn antenna is commonly used for the estimation of pavement layer thickness. However signals generated by horn antenna systems must have sufficient quality to allow the performance of automated signal processing and qualitative data analysis, especially when pavement data more sensitive to the analysis parameters, such voids or moisture, is concerned. The implementation of the horn antenna method is dependent upon, amongst others, the resolution of the antenna in use. The present research work investigates the application of the GPR sensor technique to assess voids within the asphalt layers, with a focus on the air-coupled antenna penetration depth and resolution. For this purpose the dielectric properties of asphalt layer materials were estimated and related voids contents were evaluated based on data collected by an air-coupled GPR system, operating at a 1 GHz and alternatively a 2 GHz central frequency. The collected data is analyzed comparatively for the two antennas. Comparison results indicate differences between the voids determined from the 1 GHz and 2GHz antennas. These differences are further analyzed and evaluated for pavement quality control purposes. The indication of a relationship between the measured voids is also evaluated, while ground truth data is used for the validation of the GPR data analysis results. The above is presented and discussed thoroughly with the aim to assist pavement quality assurance systems

  11. Biofuel production system with operation flexibility: Evaluation of economic and environmental performance under external disturbance

    NASA Astrophysics Data System (ADS)

    Kou, Nannan

    Biomass derived liquid hydrocarbon fuel (biofuel) has been accepted as an effective way to mitigate the reliance on petroleum and reduce the greenhouse gas emissions. An increasing demand for second generation biofuels, produced from ligno-cellulosic feedstock and compatible with current infrastructure and vehicle technologies, addresses two major challenges faced by the current US transportation sector: energy security and global warming. However, biofuel production is subject to internal disturbances (feedstock supply and commodity market) and external factors (energy market). The biofuel industry has also heavily relied on government subsidy during the early development stages. In this dissertation, I investigate how to improve the economic and environmental performance of biorefineries (and biofuel plant), as well as enhance its survivability under the external disturbances. Three types of disturbance are considered: (1) energy market fluctuation, (2) subsidy policy uncertainty, and (3) extreme weather conditions. All three factors are basically volatile, dynamic, and even unpredictable, which makes them difficult to model and have been largely ignored to date. Instead, biofuel industry and biofuel research are intensively focused on improving feedstock conversion efficiency and capital cost efficiency while assuming these advancements alone will successfully generate higher profit and thus foster the biofuel industry. The collapse of the largest corn ethanol biofuel company, Verasun Energy, in 2008 calls into question this efficiency-driven approach. A detailed analysis has revealed that although the corn ethanol plants operated by Verasun adopted the more efficient (i.e. higher ethanol yield per bushel of corn and lower capital cost) dry-mill technology, they could not maintain a fair profit margin under fluctuating market condition which made ethanol production unprofitable. This is because dry-mill plant converts a single type of biomass feedstock (corn grain) into a single primary product (ethanol). The traditional lower efficient (i.e. lower ethanol yield per bushel of corn and higher capital cost) wet-mill plant has a more diverse and adjustable product portfolio i.e. corn syrup, starch, and ethanol. The fact that only the dry-mill corn ethanol plants have bankrupted while the wet-mill corn ethanol plants have survived the late 2000s economy recession suggests that the higher conversion efficiency achieved by the dry-mill production mode has jeopardized operational flexibility, a design operational feature I agree that is indispensable for the biofuel plant's long term profit and viability. Based on the analysis of corn ethanol production, operational flexibility has been proposed as a key strategy for the next generation biofuel plants to improve its lifetime economic performance, as well as to enhance its survivability under external disturbances. This strategy requires the biofuel plant to adopt a flexible feedstock management, making it possible to utilize alternative types of biomass feedstock when the primary feedstock supply is disturbed. Biofuel plants also need to produce a wider range of final products that could meet the preference variation that either comes from the energy market or from the subsidy policy. Aspen Plus model based numerical simulations have been carried out for a thermochemical ethanol plant and a Fischer Tropsch plant (both are assumed to be located in southwest Indiana) to test this strategy under the external disturbances of extreme weather impact, different energy price projections and various subsidy policy combinations. For the thermochemical ethanol plant, effects of extreme weather conditions are mainly evaluated. It has been shown that this strategy could effectively increase the net present value of the biofuel plant and significantly decrease the GHG emission comparing with the traditional single-feedstock strategy, when the extreme weather conditions are considered. It has also been demonstrated that this strategy could significantly decrease the possibility for the bio

  12. Bucky gel of multiwalled carbon nanotubes as electrodes for high performance, flexible electric double layer capacitors

    NASA Astrophysics Data System (ADS)

    Singh, Manoj K.; Kumar, Yogesh; Hashmi, S. A.

    2013-11-01

    We report the preparation of a gelled form of multiwalled carbon nanotubes (MWCNTs) with an ionic liquid 1-butyl-1-methyl pyrrolidinium bis(trifluoromethane sulfonyl)imide (BMPTFSI)), referred to as bucky gel, to be used as binderless electrodes in electrical double layer capacitors (EDLCs). The characteristics of gelled MWCNTs are compared with pristine MWCNTs using transmission electron microscopy, x-ray diffraction and Raman studies. A gel polymer electrolyte film consisting of a blend of poly(vinylidene fluoride-co-hexafluoropropylene) and BMPTFSI, exhibiting a room temperature ionic conductivity of 1.5 10-3 S cm-1, shows its suitability as an electrolyte/separator in flexible EDLCs. The performance of EDLCs, assembled with bucky gel electrodes, using impedance spectroscopy, cyclic voltammetry and charge-discharge analyses, are compared with those fabricated with pristine MWCNT-electrodes. An improvement in specific capacitance (from 19.6 to 51.3 F g-1) is noted when pristine MWCNTs are replaced by gelled MWCNT-binderless electrodes. Although the rate performance of the EDLCs with gelled MWCNT-electrodes is reduced, the pulse power of the device is sufficiently high (10.5 kW kg-1). The gelled electrodes offer improvements in energy and power densities from 2.8 to 8.0 Wh kg-1 and 2.0 to 4.7 kW kg-1, respectively. Studies indicate that the gel formation of MWCNTs with ionic liquid is an excellent route to obtain high-performance EDLCs.

  13. PAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR)

    E-print Network

    Shan, Jie

    PAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR) Dwayne Harris, M.Sc., PG deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavement and affected by the limitations and assumptions the method used to estimate thickness. GPR provides pavement

  14. Development on preventive maintenance management system for expressway asphalt pavements

    Microsoft Academic Search

    Hu Guoxiang; Li Jie

    2010-01-01

    In view of the status that there was no expressway pavement preventive maintenance management system at home and abroad at present, based on the technology theory obtained by the author and the demands and process of expressway asphalt pavement preventive maintenance management, preventive maintenance management system for expressway asphalt pavement (EPMMS (V1.0)) was developed. The work or functions of expressway

  15. Portland Cement Concrete Pavement Shannon Golden, Alabama DOT

    E-print Network

    Portland Cement Concrete Pavement Shannon Golden, Alabama DOT PORTLAND CEMENT CONCRETE PAVEMENT PROJECT · First in Alabama in more than 25 years! · IM-I059 (342) Etowah County ­ I-59 Concrete Pavement Rehabilitation with Unbonded Concrete Overlay ­ Length: 10.9 miles ­ Thickness: 11.0 to 13.5 inches ­ Volume: 300

  16. Enhanced adaptive filter-bank-based automated pavement crack detection and segmentation system

    NASA Astrophysics Data System (ADS)

    Lettsome, Clyde A.; Tsai, Yi-Chang; Kaul, Vivek

    2012-10-01

    We incorporate, evaluate, and assess the feasibility of using filter banks in automated pavement distress systems from a system level. We integrate a novel filter-bank-based distress segmentation method, which, unlike previously researched methods, does not depend on highpass data. In addition, we incorporate the standard Said Pearlman set partitioning in hierarchical trees compression coder into the automated pavement distress system, which is a first in this area of research. A third contribution of the research is a statistical detection algorithm that assists in overall system performance. Preliminary testing using images provided by the Georgia Department of Transportation demonstrate the promise of the proposed method.

  17. On evaluating the impact of flexibility enhancing strategies on the performance of nurse schedules.

    PubMed

    Wang, Wen-Ya; Gupta, Diwakar; Potthoff, Sandra

    2009-12-01

    Hospitals develop nurse schedules that cover a period of 4-6 weeks and are posted several weeks in advance. Once posted, changes to the schedule require voluntary participation by the nurses, making it difficult for hospitals to respond to changes in nursing needs and availability of nurses. At the same time, nursing needs' forecasts developed several weeks in advance are often wrong. In each hospital setting, there may exist several promising strategies to enhance scheduling flexibility and reduce the mismatch between the nursing needs and the availability of nurses. However, methodologies to evaluate such strategies, before testing them in expensive pilot implementation, do not exist. We demonstrate how such evaluations can be carried out using historical data. Furthermore, we demonstrate the use of our approach by evaluating the benefits of a strategy where nurses are divided into two cohorts and schedules are phase shifted for the two cohorts. Staggering schedules allows nursing unit managers to benefit from more frequent updating of needs' assessments without having to change work rules. Upon applying our approach to data from a large urban hospital, we discovered that in this example staggering did not improve the performance of nurse schedules. We discuss possible reasons for this result, its implications for hospital managers, and other potential uses of our approach. PMID:19699004

  18. A biodegradable gel electrolyte for use in high-performance flexible supercapacitors.

    PubMed

    Moon, Won Gyun; Kim, Gil-Pyo; Lee, Minzae; Song, Hyeon Don; Yi, Jongheop

    2015-02-18

    Despite the significant advances in solid polymer electrolytes used for supercapacitors, intractable problems including poor ionic conductivity and low electrochemical performance limit the practical applications. Herein, we report a facile approach to synthesize a NaCl-agarose gel electrolyte for use in flexible supercapacitors. The as-prepared agarose hydrogel consists of a three-dimensional chemically interconnected agarose backbone and oriented interparticular submicropores filled with water. The interconnected agarose matrix acts as a framework that provides mechanical stability to the gel electrolyte and hierarchical porous networks for optimized ion transport. The developed pores with the water filler provide an efficient ionic pathway to the storage sites of electrode. With these properties, the gel electrolyte enables the supercapacitor to have a high specific capacitance of 286.9 F g(-1) and a high rate capability that is 80% of specific capacitance obtained in the case of a liquid electrolyte at 100 mV s(-1). In addition, attributed to the simple procedure and its components, the gel electrolyte is highly scalable, cost-effective, safe, and nontoxic. Thus, the developed gel electrolyte has the potential for use in various energy storage and delivery systems. PMID:25622040

  19. Parameter extraction for flexible photovoltaic (FPV) modules to determine high insolation performance for space solar applications

    NASA Astrophysics Data System (ADS)

    Sharma, Pooja; Duttagupta, Siddhartha P.; Agarwal, Vivek

    2009-05-01

    Space solar applications will require PV modules with large Wp/kg values with stable output characteristics under extreme insolation conditions. This report is focused on the performance of Flexible PV (FPV) modules with moderate Wp/kg ratings when exposed to sustained insolation conditions reaching a maximum of 910 Watt/m2. Three different FPV technologies have been considered, namely mono-crystalline silicon (c-Si), poly-crystalline silicon (pc-Si), and amorphous silicon (a-Si). Based on outdoor observations, the technology impact is most evident from the fill factor (FF) range demonstrated by the PV modules which is high (60 - 70%) for crystalline and polycrystalline silicon PV modules and moderate (50 - 60%) for amorphous silicon PV modules. A one diode model has been applied to all three PV modules and the theoretically calculated diode non ideality factor (n) has been compared with experimentally observed non idealities in terms of FF. Again the impact of technology is evident from 'n' value calculations which are 1.42 for c- Si, 2 for pc-Si and 3.7 for a-Si FPV modules.

  20. A sensitivity analysis of the Texas flexible pavement system

    E-print Network

    Henry, Claude Patrick

    1991-01-01

    . Fractional Factorial Analysis . ANOVA GLM Ranking Comparison 9 9 . . 10 . 13 . 14 . . 15 . . 15 Definition of Variables . . 15 Reliability . Speed . . 16 . 16 CHAPTER Base Thickness Traffic Plasticity Index Subgrade Modulus Surface... Thickness . Shoulder Type. . . . . . . . . . . . . . . AC Type . . % Voids/% AC Granular Base Modulus Month of Granular Base Modulus % Passing 4200 Vll Page 16 . . 18 . . 19 . . 19 . . 19 . . 19 . . 20 . . 20 . . 20 . . 20 21 111...

  1. An evaluation of the flexible pavement design system FPS19

    E-print Network

    Carmona, Gerardo M

    1998-01-01

    . . . . . . 31 6. Summary of Granular Base Thickness vs Temp. Constant . . . . . . . . . . . . . . . . 33 7. Summary of Granular Base Thickness vs Subgrade Modulus . . . . . . . . . . . 36 8. Summary of Granular Base Thickness vs Base Modulus.... Summary of Asph. Stab. Base Thickness vs Reliability . . . . . . 46 48 14. Summary of Asph. Stab. Base Thickness vs Temp. Constant . . . . . . . . . . . 50 15. Summary of Asph. Stab. Base Thickness vs Subgrade Modulus . . . . . . . 52 16. Summary...

  2. Influence of bending mode shape and trailing edge deflection on propulsive performance of flexible heaving fins using digital image correlation

    NASA Astrophysics Data System (ADS)

    Kancharala, Ashok K.; Dewillie, Kevin; Philen, Michael K.

    2014-03-01

    The propulsive performance of flexible flapping fins greatly depends on the stiffness of the fins along with the oscillating parameters. The bending mode shape and trailing edge deflection of the oscillating fins play a major role in the generation of thrust and efficiency. This paper examines the deformation pattern of heaving flexible foils and its dependency on propulsive performance. Experimental investigation has been carried out on fins of various lengths oscillating at their leading edge. A LaVision 2D/3D StrainMaster Digital Image Correlation (DIC) system was used to measure the deformation of the fins. It is observed that the propulsive performance can be maximized by operating at frequencies close to resonance. Trailing edge amplitude and deformation pattern together play an important role in achieving high propulsive performance even when the oscillation frequency is not close to resonant frequency.

  3. Mechanical properties of high performance fibers vis-a-vis applications in flexible structural composites

    NASA Astrophysics Data System (ADS)

    Sharma, Varunesh

    Some of the critical properties of high performance organic fibers and fiber assemblies have been addressed vis-a-vis their applications in flexible structural composites. These include: tensile properties; mechanical properties under complex modes of deformation; creep at high tensile loads; changes in physical properties due to thermo-mechanical/chemical treatments used in manufacturing of reinforced rubber goods. The axial elastic modulus of fibers and tautly twisted filament assemblies of high performance organic polymers have been measured along with their crystalline orientation distributions. Based on well established procedures in continuum mechanics of axially symmetric structures, a quantitative relationship has been derived to relate the axial elastic modulus to the second and fourth moment of average crystalline orientation distribution. The latter was determined by X-ray diffraction measurements with yarns. This model, valid for single-phase materials, has been found to provide an excellent fit of data from twisted yams of aromatic polyamide and highly ordered polyethylene fibers, with a wide range of overall crystalline orientation distributions. An important property of concern in engineering applications of polymeric filament assemblies of high performance organic fibers is creep. In this study, creep deformation data of gel-spun Ultra High Molecular Weight Polyethylne (UHMWPE) SpectraRTM 1000 yams have been fitted to a model obtained through an empirical mechanical analog of the viscoelastic process. The non-linear viscoelastic model composed of stress-dependent non-linear mechanical analogs qualitatively predicted the creep response to a series of step-loads applied on the UHMWPE yarns. To understand the mechanical properties of high performance organic fibers under combined bending and extension, a simple pin-test procedure has been employed to characterize fibers and twisted yarns. The results obtained from the test have been interpreted with regard to the mechanisms through which fibers can exhibit superior performance characteristics under such deformation conditions. An exploratory study of the changes in the mechanical properties of poly(p-phenylene terephthalamide) (PPTA) fibers due to the thermo-mechanical/chemical treatments used in commercial manufacturing of reinforced rubber goods has been conducted. The changes in tensile properties of PPTA yams have been inferred to be due to the process-induced changes in the overall crystalline orientation distribution.

  4. Highly conductive and flexible polymer composites with improved mechanical and electromagnetic interference shielding performances

    NASA Astrophysics Data System (ADS)

    Chen, Mengting; Zhang, Ling; Duan, Shasha; Jing, Shilong; Jiang, Hao; Luo, Meifang; Li, Chunzhong

    2014-03-01

    New flexible and conductive materials (FCMs) comprising a quartz fiber cloth (QFC) reinforced multi-walled carbon nanotubes (MWCNTs)-carbon aerogel (QMCA) and poly(dimethylsiloxane) (PDMS) have been successfully prepared. The QMCA-PDMS composite with a very low loading of MWCNTs (~1.6 wt%) demonstrates enhanced performance in tensile strength (129.6 MPa), modulus (3.41 GPa) and electromagnetic interference (EMI) shielding efficiency (SE) (~16 dB in X-band (8.2-12.4 GHz) region). Compared to the QC (where MWCNTs were simply deposited on the QFCs without forming aerogel networks) based PDMS composite, a ~120%, 330% and 178% increase of tensile strength, modulus, and EMI SE was obtained, respectively. Moreover, the EMI SE of the QMCA-PDMS composite can further reach 20 dB (a SE level needed for commercial applications) with only 2 wt% MWCNTs. Furthermore, the conductivity of the QMCA-PDMS laminate can reach 1.67 S cm-1 even with very low MWCNTs (1.6 wt%), which still remains constant even after 5000 times bending and exhibits an increase of ~170% than that of MWCNT-carbon aerogel (MCA)-PDMS at 20% strain. Such intriguing performances are mainly attributed to their unique networks in QMCA-PDMS composites. In addition, these features can also protect electronics against harm from external forces and EMI, giving the brand-new FCMs huge potential in next-generation devices, like E-skin, robot joints and so on.New flexible and conductive materials (FCMs) comprising a quartz fiber cloth (QFC) reinforced multi-walled carbon nanotubes (MWCNTs)-carbon aerogel (QMCA) and poly(dimethylsiloxane) (PDMS) have been successfully prepared. The QMCA-PDMS composite with a very low loading of MWCNTs (~1.6 wt%) demonstrates enhanced performance in tensile strength (129.6 MPa), modulus (3.41 GPa) and electromagnetic interference (EMI) shielding efficiency (SE) (~16 dB in X-band (8.2-12.4 GHz) region). Compared to the QC (where MWCNTs were simply deposited on the QFCs without forming aerogel networks) based PDMS composite, a ~120%, 330% and 178% increase of tensile strength, modulus, and EMI SE was obtained, respectively. Moreover, the EMI SE of the QMCA-PDMS composite can further reach 20 dB (a SE level needed for commercial applications) with only 2 wt% MWCNTs. Furthermore, the conductivity of the QMCA-PDMS laminate can reach 1.67 S cm-1 even with very low MWCNTs (1.6 wt%), which still remains constant even after 5000 times bending and exhibits an increase of ~170% than that of MWCNT-carbon aerogel (MCA)-PDMS at 20% strain. Such intriguing performances are mainly attributed to their unique networks in QMCA-PDMS composites. In addition, these features can also protect electronics against harm from external forces and EMI, giving the brand-new FCMs huge potential in next-generation devices, like E-skin, robot joints and so on. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr06092f

  5. Highly conductive and flexible polymer composites with improved mechanical and electromagnetic interference shielding performances.

    PubMed

    Chen, Mengting; Zhang, Ling; Duan, Shasha; Jing, Shilong; Jiang, Hao; Luo, Meifang; Li, Chunzhong

    2014-04-01

    New flexible and conductive materials (FCMs) comprising a quartz fiber cloth (QFC) reinforced multi-walled carbon nanotubes (MWCNTs)-carbon aerogel (QMCA) and poly(dimethylsiloxane) (PDMS) have been successfully prepared. The QMCA-PDMS composite with a very low loading of MWCNTs (?1.6 wt%) demonstrates enhanced performance in tensile strength (129.6 MPa), modulus (3.41 GPa) and electromagnetic interference (EMI) shielding efficiency (SE) (?16 dB in X-band (8.2-12.4 GHz) region). Compared to the QC (where MWCNTs were simply deposited on the QFCs without forming aerogel networks) based PDMS composite, a ?120%, 330% and 178% increase of tensile strength, modulus, and EMI SE was obtained, respectively. Moreover, the EMI SE of the QMCA-PDMS composite can further reach 20 dB (a SE level needed for commercial applications) with only 2 wt% MWCNTs. Furthermore, the conductivity of the QMCA-PDMS laminate can reach 1.67 S cm(-1) even with very low MWCNTs (1.6 wt%), which still remains constant even after 5000 times bending and exhibits an increase of ?170% than that of MWCNT-carbon aerogel (MCA)-PDMS at 20% strain. Such intriguing performances are mainly attributed to their unique networks in QMCA-PDMS composites. In addition, these features can also protect electronics against harm from external forces and EMI, giving the brand-new FCMs huge potential in next-generation devices, like E-skin, robot joints and so on. PMID:24577052

  6. A high-performance flexible fibre-shaped electrochemical capacitor based on electrochemically reduced graphene oxide.

    PubMed

    Li, Yingru; Sheng, Kaixuan; Yuan, Wenjing; Shi, Gaoquan

    2013-01-11

    A fibre-shaped solid electrochemical capacitor based on electrochemically reduced graphene oxide has been fabricated, exhibiting high specific capacitance and rate capability, long cycling life and attractive flexibility. PMID:23183591

  7. Spills on Flat Inclined Pavements

    SciTech Connect

    Simmons, Carver S.; Keller, Jason M.; Hylden, Jeff L.

    2004-03-01

    This report describes the general spill phenomenology for liquid spills occurring on relatively impermeable surfaces such as concrete or asphalt pavement and the development and application of a model to describe the time evolution of such spills. The discussion assumes evaporation and degradation are negligible and a homogeneous surface. In such an instance, the inherent interfacial properties determine the spatial extent of liquid spreading with the initial flow being controlled by the release rate of the spill and by the liquids resistance to flow as characterized by its viscosity. A variety of spill scenarios were simulated and successful implementation of the model was achieved. A linear relationship between spill area and spill volume was confirmed. The simulations showed spill rate had little effect on the final spill area. Slope had an insignificant effect on the final spill area, but did modify spill shape considerably. However, a fluid sink on the edge of the simulation domain, representing a storm drain, resulted in a substantial decrease in spill area. A bona fide effort to determine the accuracy of the model and its calculations remain, but comparison against observations from a simple experiment showed the model to correctly determine the spill area and general shape under the conditions considered. Further model verification in the form of comparison against small scale spill experiments are needed to confirm the models validity.

  8. Establishing a Dynamics Performance Envelope of a Flexible Tethered Satellite System for Planar and Non-Coplanar Models.

    NASA Astrophysics Data System (ADS)

    Teik Hong, Aaron Aw; Varatharajoo, Renuganth

    A Tethered Satellite System (TSS) can be considered as a flexible in-orbit system. However, TSS is typically modelled as a rigid tethered system due to the complexity of its mathematical treatments. In this paper, mathematical models for a flexible tethered satellite system in both planar and co-planar states are developed. The flexible tethered satellite system consists of three rigid bodies with two flexible tethers each connecting two rigid bodies with one located in the centre serving as the mothership. The TSS motion includes tether deformations, rotational dynamics, and orbital mechanics. Three materials (e.g., tungsten wire, Spectra-2000, and diamond) that are commonly used for the tether are proposed as the reference materials; and it should be noted that the tether will undergo a spinning motion as well in the motorized option. In addition, the air drag perturbation is also considered since the entire TSS is flown around Low Earth Orbit (LEO), whereby the air-drag perturbation is dominant. A comprehensive analysis was performed for planar and non-coplanar models in order to establish a dynamics performance envelope with respect to the tethers tension at different altitudes and air-drag. Bubnov-Galerkin method was employed in order to linearize the non-linear governing equations of elastic vibrations; and once the modal coordinates were obtained, they were substituted according to the equations corresponding to the energy conservation principle. Further, Lagrangian dynamics was utilized to establish the equations of motion of the entire TSS based on the chosen generalized coordinates. The proposed models were treated numerically and analysed accordingly. Then, a comparison study between the coplanar and non-coplanar models was done and the differences in their performances were observed and discussed. Although all materials have their own safe operation boundaries, the flexible TSS using Diamond shows a better dynamics performance than the other TSS options.

  9. The Performance Analysis of a Multi-Objective Immune Genetic Algorithm for Flexible Job Shop Scheduling

    Microsoft Academic Search

    Xiuli Wu; Shudong Sun; Ganggang Niu; Yinni Zhai

    2006-01-01

    First, a multi-objective immune genetic algorithm integrating immune algorithm and genetic algorithm for flexible job shop\\u000a scheduling is designed. Second, Markov chain is used to analyze quantitatively its convergence. Third, a simulation experiment\\u000a of the flexible job shop scheduling is carried out. Running results show that the proposed algorithm can converge to the Pareto\\u000a frontier quickly and distribute evenly along

  10. Reduction of traffic and tire/pavement noise: 1st year results of the Arizona Quiet Pavement Program-Site III

    NASA Astrophysics Data System (ADS)

    Reyff, James A.; Donavan, Paul

    2005-09-01

    The Arizona Quiet Pavement Pilot Program overlaid major freeway segments in the Phoenix area with an Asphalt Rubber Friction Course (ARFC). The overlay was placed on various Portland Cement Concrete Pavement (PCCP) textures. Traffic noise reductions were evaluated by performing wayside traffic noise measurements and tire/pavement source level measurements. First year results for three different study sites are presented in this paper. Depending on the texture of the initial PCCP and microphone locations, reductions of up to 12 dBA in wayside traffic noise levels were measured. Similar reductions of tire/pavement source levels were measured. Results of the two methods are compared. Traffic conditions monitored during the measurements were modeled using the Federal Highway Administration's Traffic Noise Model (TNM 2.5) to compare modeled levels to those measured for PCCP and AFRC overlay conditions. The model under predicted levels for PCCP conditions and over predicted levels for AFRC conditions. The magnitude of under or over prediction varied with distance. The effect of propagation was examined and was aided by simultaneous measurements of wind conditions made by Arizona State University. TNM 2.5 was used to identify sound wall heights that were equivalent to the traffic noise reductions provided by the AFRC overlay.

  11. Temperature control of hot-poured sealants during the sealing of pavement cracks

    Microsoft Academic Search

    J. F. Masson; P. Collins; M. Lowery

    2005-01-01

    Bituminous sealants are applied to asphalt concrete roadways to prevent the ingress of water, brine and debris in the road structure. This delays degradation and extends the pavement service life. Sealants are applied hot, yet little is known about temperature control and temperature variations during typical sealant installations and its affect on sealant properties and performance. To address this issue,

  12. Desert pavement development and landscape stability on the Eastern Libyan Plateau, Egypt

    Microsoft Academic Search

    Katherine A. Adelsberger; Jennifer R. Smith

    2009-01-01

    Desert pavement surfaces of the eastern Libyan Plateau in central Egypt represent a stable landscape preserving Middle and Upper Paleolithic artifacts. Detailed measurements of pavement clasts indicate significant variability in clast size, density, lithology and orientation between pavements, but no spatial relationship among any of these pavement variables over the study area. Pavement characteristics are unrelated to local geomorphic features

  13. Inkjet printing of flexible high-performance carbon nanotube transparent conductive films by ``coffee ring effect''

    NASA Astrophysics Data System (ADS)

    Shimoni, Allon; Azoubel, Suzanna; Magdassi, Shlomo

    2014-09-01

    Transparent and flexible conductors are a major component in many modern optoelectronic devices, such as touch screens for smart phones, displays, and solar cells. Carbon nanotubes (CNTs) offer a good alternative to commonly used conductive materials, such as metal oxides (e.g. ITO) for flexible electronics. The production of transparent conductive patterns, and arrays composed of connected CNT ``coffee rings'' on a flexible substrate poly(ethylene terephthalate), has been reported. Direct patterning is achieved by inkjet printing of an aqueous dispersion of CNTs, which self-assemble at the rim of evaporating droplets. After post-printing treatment with hot nitric acid, the obtained TCFs are characterized by a sheet resistance of 156 ? sq-1 and transparency of 81% (at 600 nm), which are the best reported values obtained by inkjet printing of conductive CNTs. This makes such films very promising as transparent conductors for various electronic devices, as demonstrated by using an electroluminescent device.

  14. Inkjet printing of flexible high-performance carbon nanotube transparent conductive films by "coffee ring effect".

    PubMed

    Shimoni, Allon; Azoubel, Suzanna; Magdassi, Shlomo

    2014-10-01

    Transparent and flexible conductors are a major component in many modern optoelectronic devices, such as touch screens for smart phones, displays, and solar cells. Carbon nanotubes (CNTs) offer a good alternative to commonly used conductive materials, such as metal oxides (e.g. ITO) for flexible electronics. The production of transparent conductive patterns, and arrays composed of connected CNT "coffee rings" on a flexible substrate poly(ethylene terephthalate), has been reported. Direct patterning is achieved by inkjet printing of an aqueous dispersion of CNTs, which self-assemble at the rim of evaporating droplets. After post-printing treatment with hot nitric acid, the obtained TCFs are characterized by a sheet resistance of 156 ? sq(-1) and transparency of 81% (at 600 nm), which are the best reported values obtained by inkjet printing of conductive CNTs. This makes such films very promising as transparent conductors for various electronic devices, as demonstrated by using an electroluminescent device. PMID:25014193

  15. A comprehensive approach for the assessment of in-situ pavement density using GPR technique

    NASA Astrophysics Data System (ADS)

    Plati, Christina; Georgiou, Panos; Loizos, Andreas

    2013-04-01

    Proper construction of the asphalt pavement is a prerequisite to developing a long lasting roadway that does not require extensive future maintenance. This goal is achieved by verifying that design specifications are met through the use of quality assurance (QA) practices. The in-situ density is regarded as one of the most important controls used to ensure that a pavement being placed is of high quality because it is a good indicator of future performance. In-situ density is frequently assessed utilizing one or more of the following three methods: cores, nuclear density gauge measurements or non-nuclear density gauge measurements. Each of the above mentioned methods, however, have their distinct disadvantages. Cores, for example, are generally considered to be the most accurate means of measuring in-situ density, however, they are a time consuming and destructive test that introduces a defect into asphalt pavements. Because of the destructive nature associated with coring, contractors and agencies have alternatively used non-destructive nuclear and non-nuclear density gauges for quality control purposes. These instruments allow for a more rapid assessment of the in-situ density, allowing measurements to be taken even during the pavement's construction. The disadvantage of these gauges are that they provide density readings only at discrete locations of the asphalt pavement mat, while no consensus exists among pavement researchers on the proper correlation between the gauges and core density. In recent years, numerous alternative methods have been introduced for the assessment of in-situ density, both during asphalt pavement construction and afterwards. These methods include, amongst others, intelligent compaction, thermal imaging and ground penetrating radar (GPR). Among these methods, GPR has been defined as both a technically feasible and promising method for the nondestructive, rapid, and continuous evaluation of in-situ asphalt pavement density based on electromagnetic mixing (EM) theory, through the utilization of proper models. These models enable the prediction of asphalt mixture density dependent on its bulk dielectric constant as measured by the GPR, the dielectric properties of the asphalt mix materials, as well as other material information. The goal of the present study is to attempt to verify the prediction performance of various density models. To accomplish this goal GPR surveys were carried out in the field during asphalt pavement construction to evaluate the density results due to different compaction modes. The GPR data was analyzed to calculate the appropriate asphalt mix dielectric properties needed for the activation of the considered density prediction models. Predicted densities were compared with densities of the field cores extracted from the as-built asphalt pavement prior to trafficking. It was found that the predicted density values were significantly lower when compared to the ground truth data. A further investigation of the effect of temperature on GPR readings showed that GPR seems to overestimate the in-situ density. However, this approach could be used effectively to evaluate the performance of different compaction methods and set up the compaction pattern that is needed to achieve the desired asphalt pavement density.

  16. Ultrathin cerium orthovanadate nanobelts for high-performance flexible all-solid-state asymmetric supercapacitors.

    PubMed

    He, Junzhi; Zhao, Junhong; Run, Zhen; Sun, Mengjun; Pang, Huan

    2015-02-01

    Ultrathin CeVO4 nanobelts were successfully synthesized by a hydrothermal method. The thickness of a single nanobelt is about 2.4?nm, which can effectively shorten the ion diffusion and fasten the charge pathway. More importantly, ultrathin CeVO4 nanobelts and graphene are easily assembled as a flexible all-solid-state asymmetric device, which shows a highly flexible property and achieves a maximum energy density of 0.78?mW?h?cm(-3) and a high life cycle of >6000?cycles. PMID:25410018

  17. On performance of an oscillating plate underwater propulsion system with variable chordwise flexibility at different depths of submergence

    NASA Astrophysics Data System (ADS)

    Barannyk, Oleksandr; Buckham, Bradley J.; Oshkai, Peter

    2012-01-01

    In this work, an oscillating plate propulsor undergoing a combination of heave translation and pitch rotation is investigated experimentally. The oscillation kinematics are inspired by swimming mechanisms employed by fish and other marine animals. The primary focus was on the propulsive characteristics of such oscillating plates, which were studied by means of direct force measurements in the thrust-producing regime. Experiments were performed at constant Reynolds number and constant heave amplitude. By varying the Strouhal number, the depth of submergence and the chordwise flexibility of the plate, it was possible to investigate corresponding changes in the generated thrust and the hydromechanical efficiency. It was possible to establish a set of parameters, including the driving frequency of the system, the ratio of rigid to flexible segment length of the plate, and the range of Strouhal numbers that led to an overall increase in thrust and efficiency. The experiments, involving plates with various ratios of rigid to flexible segment lengths, showed that greater flexibility increased the propulsive efficiency and thrust compared to an identical motion of the purely rigid plate. By submerging the plate at different depths, it was observed that the proximity of the propulsor to the bottom of the channel led to an overall increase in the thrust coefficient across the oscillation frequencies considered. The flow visualization revealed the formation of large dynamic stall vortices that influenced the wake structure, and suggested that their constructive interaction with trailing edge vortices might lead to overall improvement of thrust and efficiency.

  18. Transparent conducting films of hierarchically nanostructured polyaniline networks on flexible substrates for high-performance gas sensors.

    PubMed

    Bai, Shouli; Sun, Chaozheng; Wan, Pengbo; Wang, Cheng; Luo, Ruixian; Li, Yaping; Liu, Junfeng; Sun, Xiaoming

    2015-01-21

    Transparent chemical gas sensors are assembled from a transparent conducting film of hierarchically nanostructured polyaniline (PANI) networks fabricated on a flexible PET substrate, by coating silver nanowires (Ag NWs) followed by the in situ polymerization of aniline near the sacrificial Ag NW template. The sensor exhibits enhanced gas sensing performance at room temperature in both sensitivity and selectivity to NH3 compared to pure PANI film. PMID:25164185

  19. Permeable Pavements, Green Roofs, and Cisterns

    E-print Network

    Hunt, William F.

    examples of appropriate uses for permeable pavements include patios, residential parking pads, driveways opportunity regardless of race, color, creed, national origin, religion, sex, age, or disability. In addition, fire lanes, overflow parking areas, and some daily parking areas. For runoff reduction, a per- meable

  20. Permeable pavement research ? Edison, New Jersey

    EPA Science Inventory

    These are the slides for the New York City Concrete Promotional Council Pervious Concrete Seminar presentation. The basis for the project, the monitoring design and some preliminary monitoring data from the permeable pavement parking lot at the Edison Environmental Center are pre...

  1. Innovations in Pavement Recycling Session CTS Conference

    E-print Network

    Minnesota, University of

    Innovations in Pavement Recycling Session CTS Conference April 27, 2010 Jill M. Thomas, P !! Single lane construction zone !! Both have benefits #12;Case Example: Freeborn County Rubblization Bituminous #12;Many Benefits !! Cost savings. !! No new r.o.w. needed, thus no impact to wetlands

  2. PAVEMENT TECHNOLOGY UPDATE This Technology Transfer Program

    E-print Network

    California at Berkeley, University of

    the road." In recent years, increasing amounts of crumb rubber from recycled tires have been added solve the very serious problem of waste tire disposal. TECHNOLOGY TRANSFER PROGRAM SEPTEMBER 2009, VOL. 1, NO. 2 Rubber Roads: Waste Tires Find a Home By Larry Santucci, PE Pavement Specialist

  3. Performance of HS-HR Flexible Foams in Small Open-flame Combustibility Tests

    Microsoft Academic Search

    Richard Skorpenske; Michael Blaszkiewicz; Michael Masciantonio

    2004-01-01

    The development of small open-flame tests for measuring or predicting the combustibility characteristics of flexible polyurethane foams continues to be a subject of broad interest and active research. Notable recent activities in the residential furniture area include: (1) efforts by the California Bureau of Home Furnishings and Thermal Insulation to improve CAL TB 117; (2) work towards a national standard

  4. Influence of a front buffer layer on the performance of flexible Cadmium sulfide/Cadmium telluride solar cells

    NASA Astrophysics Data System (ADS)

    Mahabaduge, Hasitha Padmika

    Cadmium telluride (CdTe) solar cells have been developing as a promising candidate for large-scale application of photovoltaic energy conversion and have become the most commercially successful polycrystalline thin-film solar module material. In scaling up from small cells to large-area modules, inevitably non-uniformities across the large area will limit the performance of the large cell or module. The effects of these non-uniformities can be reduced by introducing a thin, high-resistivity transparent buffer layer between the conductive electrodes and the semiconductor diode. ZnO is explored in this dissertation as a high-resistivity transparent buffer layer for sputtered CdTe solar cells and efficiencies over 15% have been achieved on commercially available Pilkington TEC15M glass substrates. The highest open-circuit voltage of 0.858V achieved using the optimized ZnO buffer layer is among the best reported in the literature. The properties of ZnO:Al as a buffer are also investigated. We have shown that ZnO:Al can serve both as a transparent conducting oxide layer as well as a high-resistivity transparent layer for CdTe solar cells. ZnO:Al reactively sputtered with oxygen can give the necessary resistivities that allow it to be used as a high-resistivity transparent layer. Glass is the most common choice as the substrate for solar cells fabricated in the superstrate configuration due to its transparency and mechanical rigidity. However flexible substrates offer the advantages of light weight, high flexibility, ease of integrability and higher throughput through roll-to-roll processing over glass. This dissertation presents significant improvements made to flexible CdTe solar cells reporting an efficiency of 14% on clear KaptonRTM flexible polyimide substrates. Our efficiency of 14% is, to our knowledge, the best for any flexible CdTe cell reported in literature.

  5. 76 FR 67018 - Notice to Manufacturers of Airport In-Pavement Stationary Runway Weather Information Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ...Airport In-Pavement Stationary Runway Weather Information Systems AGENCY: Federal Aviation...Manufacturers of In-Pavement Stationary Runway Weather Information Systems...Passive In- Pavement Stationary Runway Weather Information Systems that meet the...

  6. 78 FR 26847 - Including Specific Pavement Types in Federal-aid Highway Traffic Noise Analyses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ...Including Specific Pavement Types in Federal-aid Highway Traffic Noise Analyses AGENCY...specific pavement types used in Federal-aid highway traffic noise analyses. Current...include additional pavement types in Federal-aid highway traffic noise analyses....

  7. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide.2 2 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  8. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide.2 2 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  9. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  10. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  11. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide.2 2 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  12. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...208 Indian lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  13. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  14. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  15. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide.2 2 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  16. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...208 Indian lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  17. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...208 Indian lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  18. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...208 Indian lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  19. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide.2 2 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  20. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Federal lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  1. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...208 Indian lands pavement management system (PMS). In addition...the AASHTO's Pavement Management Guide. 1 1 Pavement Management Guide, AASHTO...framework for a PMS: (1) A database and an ongoing...

  2. Room temperature synthesis of cobalt-manganese-nickel oxalates micropolyhedrons for high-performance flexible electrochemical energy storage device.

    PubMed

    Zhang, Yi-Zhou; Zhao, Junhong; Xia, Jing; Wang, Lulu; Lai, Wen-Yong; Pang, Huan; Huang, Wei

    2015-01-01

    Cobalt-manganese-nickel oxalates micropolyhedrons were successfully fabricated by a room temperature chemical co-precipitation method. Interestingly, the Co0.5Mn0.4Ni0.1C2O4*nH2O micropolyhedrons and graphene nanosheets have been successfully applied as the positive and negative electrode materials (a battery type Faradaic electrode and a capacitive electrode, respectively) for flexible solid-state asymmetric supercapacitors. More importantly, the as-assembled device achieved a maximum energy density of 0.46?mWhcm(-3), a decent result among devices with similar structures. The as-assembled device showed good flexibility, functioning well under both normal and bent conditions (0-180). The resulting device showed little performance decay even after 6000 cycles, which rendered the Co0.5Mn0.4Ni0.1C2O4*nH2O//Graphene device configuration a promising candidate for high-performance flexible solid-state asymmetric supercapacitors in the field of high-energy-density energy storage devices. PMID:25705048

  3. Room temperature synthesis of cobalt-manganese-nickel oxalates micropolyhedrons for high-performance flexible electrochemical energy storage device

    NASA Astrophysics Data System (ADS)

    Zhang, Yi-Zhou; Zhao, Junhong; Xia, Jing; Wang, Lulu; Lai, Wen-Yong; Pang, Huan; Huang, Wei

    2015-02-01

    Cobalt-manganese-nickel oxalates micropolyhedrons were successfully fabricated by a room temperature chemical co-precipitation method. Interestingly, the Co0.5Mn0.4Ni0.1C2O4*nH2O micropolyhedrons and graphene nanosheets have been successfully applied as the positive and negative electrode materials (a battery type Faradaic electrode and a capacitive electrode, respectively) for flexible solid-state asymmetric supercapacitors. More importantly, the as-assembled device achieved a maximum energy density of 0.46 mWh.cm-3, a decent result among devices with similar structures. The as-assembled device showed good flexibility, functioning well under both normal and bent conditions (0-180). The resulting device showed little performance decay even after 6000 cycles, which rendered the Co0.5Mn0.4Ni0.1C2O4*nH2O//Graphene device configuration a promising candidate for high-performance flexible solid-state asymmetric supercapacitors in the field of high-energy-density energy storage devices.

  4. Room temperature synthesis of cobalt-manganese-nickel oxalates micropolyhedrons for high-performance flexible electrochemical energy storage device

    PubMed Central

    Zhang, Yi-Zhou; Zhao, Junhong; Xia, Jing; Wang, Lulu; Lai, Wen-Yong; Pang, Huan; Huang, Wei

    2015-01-01

    Cobalt-manganese-nickel oxalates micropolyhedrons were successfully fabricated by a room temperature chemical co-precipitation method. Interestingly, the Co0.5Mn0.4Ni0.1C2O4*nH2O micropolyhedrons and graphene nanosheets have been successfully applied as the positive and negative electrode materials (a battery type Faradaic electrode and a capacitive electrode, respectively) for flexible solid-state asymmetric supercapacitors. More importantly, the as-assembled device achieved a maximum energy density of 0.46?mWhcm?3, a decent result among devices with similar structures. The as-assembled device showed good flexibility, functioning well under both normal and bent conditions (0180). The resulting device showed little performance decay even after 6000 cycles, which rendered the Co0.5Mn0.4Ni0.1C2O4*nH2O//Graphene device configuration a promising candidate for high-performance flexible solid-state asymmetric supercapacitors in the field of high-energy-density energy storage devices. PMID:25705048

  5. Doping stability and opto-electronic performance of CVD graphene on transparent flexible substrates

    E-print Network

    Kang, Moon Hyo; Milne, William I.; Cole, Matthew T.

    2014-07-15

    applications including organic light emitting diodes, [3-6] touch screens, [5, 7, 8] and photovoltaic cells. [9-11] Graphene is mechanically flexible, does not readily form micro-cracks when strained and, when coupled with suitable substrates, provides... in OLED displays and next-generation photovoltaic devices. Kang et al. IET: Graphene Electronics Special Issue - - 19 Acknowledgements M. T. Cole thanks the Winston Churchill Trust and the International Young Scientist Research Fellowship...

  6. The effect of flexible substrates on pressure-sensitive adhesive performance

    Microsoft Academic Search

    A. J Steven-Fountain; A. G Atkins; G Jeronimidis; J. F. V Vincent; D. F Farrar; R. A Chivers

    2002-01-01

    The adhesive fracture energy (fracture toughness) of tapes during globally elastic unpeeling is often calculated from the relation G=P\\/b(1?cos?). We show that while this expression is correct for elastic peeling from rigid substrates, it gives misleading results when peeling from reversible flexible substrates. A two-dimensional analysis is presented for peeling from non-linear elastic substrates that give consistent fracture energies from

  7. Impact of magnetic isolation on pointing system performance in the presence of structural flexibility

    NASA Technical Reports Server (NTRS)

    Seller, J.

    1985-01-01

    The inertial pointing stability of a gimbal pointing system (AGS) was compared with a magnetic pointing/gimbal followup system (ASPS), under certain conditions of system structural flexibility and disturbance inputs from the gimbal support structure. Separate 3 degree-of-freedom (3DOF) linear models based on NASTRAN modal flexibility data for the gimbal and support structures were generated for the ASPS configurations. Using the models inertial pointing control loops providing 6dB of gain margin and 45 deg of phase margin were defined for each configuration. The pointing loop bandwidth obtained for the ASPS is more than twice the level achieved for the AGS configuration. The AGS limit is attributed to the gimbal and support structure flexibility. As a result of the higher ASPS pointing loop bandwidth and the disturbance rejection provided by the magnetic isolation ASPS pointing performane is significantly better than that of the AGS system. The low frequency peak of the ASPS transfer function from base disturbance to payload angular motion is almost 60dB lower than AGS low frequency peak.

  8. Thermal cracking of rubber modified pavements, May 1995. Final report

    SciTech Connect

    Raad, L.; Yuan, X.; Saboundjian, S.

    1995-05-01

    In accordance with the original ISTEA mandate (1991) to use crumb tire rubber in pavements, Alaska would be required to use about 250 tons of used tire rubber starting in 1994 and increasing to about 1,000 tons of rubber in 1997 and each year thereafter. A number of pavements using crumb rubber modifiers have been built in the state and have been in service for periods of 8 to 15 years. Knowledge of the behavior of these rubber-modified pavements under extreme climate conditions, particularly in relation to their low temperature cracking resistance, is necessary for future design and construction of rubberized pavements in Alaska. This report presents results of a study to determine the low temperature cracking resistance of rubber modified pavements in Alaska in comparison with conventional asphalt concrete pavements.

  9. MODELING PAVEMENT DETERIORATION PROCESSES BY POISSON HIDDEN MARKOV MODELS

    NASA Astrophysics Data System (ADS)

    Nam, Le Thanh; Kaito, Kiyoyuki; Kobayashi, Kiyoshi; Okizuka, Ryosuke

    In pavement management, it is important to estimate lifecycle cost, which is composed of the expenses for repairing local damages, including potholes, and repairing and rehabilitating the surface and base layers of pavements, including overlays. In this study, a model is produced under the assumption that the deterioration process of pavement is a complex one that includes local damages, which occur frequently, and the deterioration of the surface and base layers of pavement, which progresses slowly. The variation in pavement soundness is expressed by the Markov deterioration model and the Poisson hidden Markov deterioration model, in which the frequency of local damage depends on the distribution of pavement soundness, is formulated. In addition, the authors suggest a model estimation method using the Markov Chain Monte Carlo (MCMC) method, and attempt to demonstrate the applicability of the proposed Poisson hidden Markov deterioration model by studying concrete application cases.

  10. DEFLECTIONS MEASURED ON EXPERIMENTAL ULTRA-THIN WHITETOPPING PAVEMENTS

    Microsoft Academic Search

    Xicheng Qi; James A. Sherwood; FHWA Terry Mitchell

    In the spring of 1998, the Federal Highway Administration (FHWA) and the American Concrete Pavement Association (ACPA) jointly constructed eight full-scale lanes of ultra-thin whitetopping (UTW) over existing hot mix asphalt (HMA) pavements. These sections were placed at the FHWA's Pavement Test Facility, located at the Turner-Fairbank Highway Research Center in McLean, Virginia. The experiment employed various combinations of thickness,

  11. Implications of reliability in mechanistic/empirical pavement design applications

    E-print Network

    Killingsworth, Brian Mark

    1994-01-01

    in Mechanistic/Empirical Pavement Design Applications. (May 1994) Brian Mark Killingsworth, B. S. Texas ASSAM University Chair of Advisory Committee: Dr. Dan G. Zollinger At present there are many design procedures for both asphalt and concrete pavement... probabilistic-based design which evaluates reliability. Zollinger and Lytton state: "Design reliability is an indelible aspect of the pavement design process and needs to be genuinely considered and weighted equally with other design factors included...

  12. Solution processable colloidal nanoplates as building blocks for high-performance electronic thin films on flexible substrates.

    PubMed

    Lin, Zhaoyang; Chen, Yu; Yin, Anxiang; He, Qiyuan; Huang, Xiaoqing; Xu, Yuxi; Liu, Yuan; Zhong, Xing; Huang, Yu; Duan, Xiangfeng

    2014-11-12

    Low-temperature solution-processed electronic materials on plastic substrates are of considerable interest for flexible electronics. Solution dispersible inorganic nanostructures (e.g., zero-dimensional (0D) quantum dots or one-dimensional (1D) nanowires) have emerged as interesting ink materials for low-temperature solution processing of electronic thin films on flexible substrates, but usually with limited performance due to the large number of grain boundaries (0D) or incomplete surface coverage (1D). Here, we report two-dimensional (2D) colloidal nanoplates of layered materials as a new ink material for solution assembly of high-performance electronic thin films. The 2D colloidal nanoplates exhibit few dangling bonds and represent an ideal geometry for the assembly of highly uniform continuous thin films with greatly reduced grain boundaries dictated by large-area conformal plane-plane contact with atomically flat/clean interfaces. It can therefore promise efficient charge transport across neighboring nanoplates and throughout the entire thin film to enable unprecedented electronic performance. We show that Bi2Se3 and Bi2Te3 nanoplates can be synthesized with well-controlled thickness (6-15 nm) and lateral dimension (0.5-3 ?m) and can be used for the assembly of highly uniform continuous thin films with a full surface coverage and an excellent room temperature carrier mobility >100 cm(2)V(-1)s(-1), approaching that of chemical vapor deposition grown materials. Our study demonstrates a general strategy to using 2D nanoplates as a unique building block for the construction of high-performance electronic thin films on plastic substrates for future flexible electronics and optoelectronics. PMID:25343683

  13. High-performance all-solid-state flexible supercapacitors based on two-step activated carbon cloth

    NASA Astrophysics Data System (ADS)

    Jiang, Shulan; Shi, Tielin; Zhan, Xiaobin; Long, Hu; Xi, Shuang; Hu, Hao; Tang, Zirong

    2014-12-01

    A simple and effective strategy is proposed to activate carbon cloth for the fabrication of flexible and high-performance supercapacitors. Firstly, the carbon cloth surface is exfoliated as nanotextures through wet chemical treatment, then an annealing process is applied at H2/N2 atmosphere to reduce the surface oxygen functional groups which are mainly introduced from the first step. The activated carbon cloth electrode shows excellent wettablity, large surface area and delivers remarkable electrochemical performance. A maximum areal capacitance of 485.64mFcm-2 at the current density of 2mAcm-2 is achieved for the activated carbon cloth electrode, which is considerably larger than the resported results for carbon cloth. Furthermore, the flexible all-solid-state supercapacitor, which is fabricated based on the activated carbon cloth electrodes, shows high areal capacitance, superior cycling stability as well as stable electrochemical performance even under constant bending or twisting conditions. An areal capacitance of 161.28mFcm-2 is achieved at the current density of 12.5mAcm-2, and 104% of its initial capacitance is retained after 30,000 charging/discharging cycles. This study would also provide an effective way to boost devices' electrochemical performance by accommodating other active materials on the activated carbon cloth.

  14. Pavement rehabilitation and funds allocation for a transportation network

    E-print Network

    Stein, Alvaro

    1985-01-01

    Continuously reinforced concrete pavement Jointed reinforced concrete pavement Jointed plain concrete pavement EP-4 EP-5 EP-6 EP-7 EP-8 EP-9 EP-10 Thick asphaltic concrete pavement (greater than 5 1/2" of hot-mixed asphaltic layers) Intermediate... condition of a h1ghway segment. AVU = Adjusted v 1sual defect utility. SIU = Serviceability index utility. SKU = Sk1 d number utility SCU = Structural Capac1ty ut1lity. al, a2, a3, a4 = Weighting factors. 1 1 (ADTF)(KEF) 2 3 4 ADTF = Average daily...

  15. Hybrid green permeable pave with hexagonal modular pavement systems

    NASA Astrophysics Data System (ADS)

    Rashid, M. A.; Abustan, I.; Hamzah, M. O.

    2013-06-01

    Modular permeable pavements are alternatives to the traditional impervious asphalt and concrete pavements. Pervious pore spaces in the surface allow for water to infiltrate into the pavement during rainfall events. As of their ability to allow water to quickly infiltrate through the surface, modular permeable pavements allow for reductions in runoff quantity and peak runoff rates. Even in areas where the underlying soil is not ideal for modular permeable pavements, the installation of under drains has still been shown to reflect these reductions. Modular permeable pavements have been regarded as an effective tool in helping with stormwater control. It also affects the water quality of stormwater runoff. Places using modular permeable pavement has been shown to cause a significant decrease in several heavy metal concentrations as well as suspended solids. Removal rates are dependent upon the material used for the pavers and sub-base material, as well as the surface void space. Most heavy metals are captured in the top layers of the void space fill media. Permeable pavements are now considered an effective BMP for reducing stormwater runoff volume and peak flow. This study examines the extent to which such combined pavement systems are capable of handling load from the vehicles. Experimental investigation were undertaken to quantify the compressive characteristics of the modular. Results shows impressive results of achieving high safety factor for daily life vehicles.

  16. High-performance bilayer flexible resistive random access memory based on low-temperature thermal atomic layer deposition

    PubMed Central

    2013-01-01

    We demonstrated a flexible resistive random access memory device through a low-temperature atomic layer deposition process. The device is composed of an HfO2/Al2O3-based functional stack on an indium tin oxide-coated polyethylene terephthalate substrate. After the initial reset operation, the device exhibits a typical bipolar, reliable, and reproducible resistive switching behavior. After a 104-s retention time, the memory window of the device is still in accordance with excellent thermal stability, and a 10-year usage is still possible with the resistance ratio larger than 10 at room temperature and at 85C. In addition, the operation speed of the device was estimated to be 500 ns for the reset operation and 800 ns for the set operation, which is fast enough for the usage of the memories in flexible circuits. Considering the excellent performance of the device fabricated by low-temperature atomic layer deposition, the process may promote the potential applications of oxide-based resistive random access memory in flexible integrated circuits. PMID:23421424

  17. Carbon nanotube network film directly grown on carbon cloth for high-performance solid-state flexible supercapacitors

    NASA Astrophysics Data System (ADS)

    Zhou, Cheng; Liu, Jinping

    2014-01-01

    Carbon nanotubes (CNTs) have received increasing attention as electrode materials for high-performance supercapacitors. We herein present a straightforward method to synthesize CNT films directly on carbon cloths as electrodes for all-solid-state flexible supercapacitors (AFSCs). The as-made highly conductive electrodes possess a three-dimensional (3D) network architecture for fast ion diffusion and good flexibility, leading to an AFSC with a specific capacitance of 106.1 F g-1, an areal capacitance of 38.75 mF cm-2, an ultralong cycle life of 100?000 times (capacitance retention: 99%), a good rate capability (can scan at 1000 mV s-1, at which the capacitance is still 37.8% of that at 5 mV s-1), a high energy density (2.4 ?W h cm-2) and a high power density (19 mW cm-2). Moreover, our AFSC maintains excellent electrochemical attributes even with serious shape deformation (bending, folding, etc), high mechanical pressure (63 kPa) and a wide temperature window (up to 100? C). After charging for only 5 s, three such AFSC devices connected in series can efficiently power a red round LED for 60 s. Our work could pave the way for the design of practical AFSCs, which are expected to be used for various flexible portable/wearable electronic devices in the future.

  18. Intra-Seasonal Flexibility in Avian Metabolic Performance Highlights the Uncoupling of Basal Metabolic Rate and Thermogenic Capacity

    PubMed Central

    Petit, Magali; Lewden, Agns; Vzina, Franois

    2013-01-01

    Stochastic winter weather events are predicted to increase in occurrence and amplitude at northern latitudes and organisms are expected to cope through phenotypic flexibility. Small avian species wintering in these environments show acclimatization where basal metabolic rate (BMR) and maximal thermogenic capacity (MSUM) are typically elevated. However, little is known on intra-seasonal variation in metabolic performance and on how population trends truly reflect individual flexibility. Here we report intra-seasonal variation in metabolic parameters measured at the population and individual levels in black-capped chickadees (Poecileatricapillus). Results confirmed that population patterns indeed reflect flexibility at the individual level. They showed the expected increase in BMR (6%) and MSUM (34%) in winter relative to summer but also, and most importantly, that these parameters changed differently through time. BMR began its seasonal increase in November, while MSUM had already achieved more than 20% of its inter-seasonal increase by October, and declined to its starting level by March, while MSUM remained high. Although both parameters co-vary on a yearly scale, this mismatch in the timing of variation in winter BMR and MSUM likely reflects different constraints acting on different physiological components and therefore suggests a lack of functional link between these parameters. PMID:23840843

  19. Laboratory evaluation of selected syncrude products and upgraded by-products as pavement-recycling agents

    SciTech Connect

    Holmgreen, R.J. Jr.; Epps, J.A.; Button, J.W.; Cook, O.C.

    1982-01-01

    The following conclusions appear warranted based on the information derived from this study: (1) Selected syncrude products and upgraded by-products may be successfully used as recycling agents for field aged asphalt pavements. Those tested in this study performed equally as well as the commercially produced recycling agents. (2) Several of the blends containing the syncrude recycling agents exhibited excessive hardening and weight loss upon exposure to the thin film oven test. (3) Properties of recycled mixtures are highly dependent upon the type and amount of recycling agent. (4) The Rostler-Sternberg separation analysis on both the syncrudes and syncrude blends does not seem to produce results that correlate with other recycling agents. (5) Rostler-Sternberg analysis indicated a relatively high fraction of nitrogen bases in the syncrude additives, particularly those from shale oil. Although basic nitrogen in asphalts has been associated with improved resistance to moisture, recycled mixtures containing these materials did not exhibit any significant improvement in resistance to damage by water. Recycled mixtures containing recycling agent 4 (a soft tar sand asphalt) imparted excellent flexibility and yet adequate strength to paving mixtures at low service temperatures. (7) All of the blends containing the syncrude-based recycling agents, except California Coastal with recycling agent 3 (Tar Sand Asphalt and Stabilized Shale Oil), met criteria set forth by Halstead and Krchma for acceptable field performance. (8) The syncrude-based recycling agents produced blends with Rostler parameters and N/P values nearer those of the original asphalts than the commercial recycling agents. (9) According to Rostler-Sternberg analyses, none of the recycling agents were able to restore a base asphalt to its original composition, but this was not and should be not expected. 33 figures, 21 tables.

  20. Smart Road Pavement Research HomePage

    NSDL National Science Digital Library

    Dubbed "the Smart Road" by Virginia's Department of Transportation, this full-scale facility for pavement research and evaluation of high-tech transportation systems uses computers, electronics, and satellites to create a realistic environment for collecting traffic and environmental data under controlled conditions, "and should advance the general understanding of the engineering behavior of pavement systems." This site, from the Virginia Tech Civil Engineering Materials Program, provides information from the researchers who have designed the Smart Road. The page contains a description of the project's current status, an explanation of objectives, construction photos, a detailed description of the instrumentation used, and data. Note, the research plan and testing links are still under construction. This site introduces an interesting project for highway and transportation engineers.

  1. Structural control of a flexible satellite bus for improved jitter performance

    NASA Astrophysics Data System (ADS)

    Jacobs, Jack H.; Hyde, T. Tupper; Boyd, Jim; Hadden, Steve; Davis, L. Porter

    1998-06-01

    The increasing demand for global communications and limitations on RF communications bandwidth has driven several constellations to baseline laser cross-links between the satellites within their constellations. The use of laser communications over a long distance dictates the need for accurate pointing and jitter suppression in order to maintain signal continuity. Vibrations upon a satellite bus or orbit come from several sources including: momentum systems, flexible appendages, motors and cryocoolers. Attenuation of these vibrations requires a combination of disturbance reduction, disturbance isolation, payload isolation, input command shaping, appendage damping and passive/active bus structural control. This paper addresses these techniques in a systems approach to satellite structural control. Experimental results from a representative flexible satellite truss structure using a series of integral D-Strut structural dampers is presented. The passive damping system is used to reduce resonant amplification of disturbances on precision optical equipment jitter. The use of different combinations of longitudinal, transverse and diagonal dampers is discussed to achieve specific modal damping. In addition, the design of the integral truss dampers is discussed along with their application to satellite bus construction.

  2. Ultrahigh Performance C60 Nanorod Large Area Flexible Photoconductor Devices via Ultralow Organic and Inorganic Photodoping

    PubMed Central

    Saran, Rinku; Stolojan, Vlad; Curry, Richard J.

    2014-01-01

    One dimensional single-crystal nanorods of C60 possess unique optoelectronic properties including high electron mobility, high photosensitivity and an excellent electron accepting nature. In addition, their rapid large scale synthesis at room temperature makes these organic semiconducting nanorods highly attractive for advanced optoelectronic device applications. Here, we report low-cost large-area flexible photoconductor devices fabricated using C60 nanorods. We demonstrate that the photosensitivity of the C60 nanorods can be enhanced ~400-fold via an ultralow photodoping mechanism. The photodoped devices offer broadband UV-vis-NIR spectral tuneability, exhibit a detectivitiy >109 Jones, an external quantum efficiency of ~100%, a linear dynamic range of 80?dB, a rise time 60?s and the ability to measure ac signals up to ~250?kHz. These figures of merit combined are among the highest reported for one dimensional organic and inorganic large-area planar photoconductors and are competitive with commercially available inorganic photoconductors and photoconductive cells. With the additional processing benefits providing compatibility with large-area flexible platforms, these devices represent significant advances and make C60 nanorods a promising candidate for advanced photodetector technologies. PMID:24853479

  3. Ultrahigh Performance C60 Nanorod Large Area Flexible Photoconductor Devices via Ultralow Organic and Inorganic Photodoping

    NASA Astrophysics Data System (ADS)

    Saran, Rinku; Stolojan, Vlad; Curry, Richard J.

    2014-05-01

    One dimensional single-crystal nanorods of C60 possess unique optoelectronic properties including high electron mobility, high photosensitivity and an excellent electron accepting nature. In addition, their rapid large scale synthesis at room temperature makes these organic semiconducting nanorods highly attractive for advanced optoelectronic device applications. Here, we report low-cost large-area flexible photoconductor devices fabricated using C60 nanorods. We demonstrate that the photosensitivity of the C60 nanorods can be enhanced ~400-fold via an ultralow photodoping mechanism. The photodoped devices offer broadband UV-vis-NIR spectral tuneability, exhibit a detectivitiy >109 Jones, an external quantum efficiency of ~100%, a linear dynamic range of 80 dB, a rise time 60 s and the ability to measure ac signals up to ~250 kHz. These figures of merit combined are among the highest reported for one dimensional organic and inorganic large-area planar photoconductors and are competitive with commercially available inorganic photoconductors and photoconductive cells. With the additional processing benefits providing compatibility with large-area flexible platforms, these devices represent significant advances and make C60 nanorods a promising candidate for advanced photodetector technologies.

  4. Stable Bending Performance of Flexible Organic Light-Emitting Diodes Using IZO Anodes

    PubMed Central

    Kwak, Kiyeol; Cho, Kyoungah; Kim, Sangsig

    2013-01-01

    We report luminescent characteristics and mechanical stability of a flexible organic light-emitting diode (FOLED) using an amorphous ZnO-doped In2O3 (a-IZO) anode with a low sheet resistance of and a high optical transparency of 86%. The FOLED consisting of a-IZO/poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS)/poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4, 8-diyl)] (F8BT)/LiF/Al exhibits the efficient luminescent characteristics, which are nearly identical with the photoluminescence spectrum of the organic emitting material in our FOLED. This observation clearly indicates that the luminescent characteristics of the FOLED are solely ascribed to molecular exciton formation within the F8BT layer, since exciplex and charge transfer exciton formation are strictly suppressed by both tunneling/thermionic injection of holes at the PEDOT:PSS/F8BT interface and enhanced hole transport. Furthermore, the use of the considerably flexible a-IZO anode and PEDOT:PSS acting as a strain-relief buffering material enables good retention of the efficient luminescent characteristics of the FOLED even after continuous bending of up to 1000 times. PMID:24071803

  5. High-performance NiO/Ag/NiO transparent electrodes for flexible organic photovoltaic cells.

    PubMed

    Xue, Zhichao; Liu, Xingyuan; Zhang, Nan; Chen, Hong; Zheng, Xuanming; Wang, Haiyu; Guo, Xiaoyang

    2014-09-24

    Transparent electrodes with a dielectric-metal-dielectric (DMD) structure can be implemented in a simple manufacturing process and have good optical and electrical properties. In this study, nickel oxide (NiO) is introduced into the DMD structure as a more appropriate dielectric material that has a high conduction band for electron blocking and a low valence band for efficient hole transport. The indium-free NiO/Ag/NiO (NAN) transparent electrode exhibits an adjustable high transmittance of ?82% combined with a low sheet resistance of ?7.6 ?sq(-1) and a work function of 5.3 eV after UVO treatment. The NAN electrode shows excellent surface morphology and good thermal, humidity, and environmental stabilities. Only a small change in sheet resistance can be found after NAN electrode is preserved in air for 1 year. The power conversion efficiencies of organic photovoltaic cells with NAN electrodes deposited on glass and polyethylene terephthalate (PET) substrates are 6.07 and 5.55%, respectively, which are competitive with those of indium tin oxide (ITO)-based devices. Good photoelectric properties, the low-cost material, and the room-temperature deposition process imply that NAN electrode is a striking candidate for low-cost and flexible transparent electrode for efficient flexible optoelectronic devices. PMID:25148532

  6. Multimodal approach to seismic pavement testing

    USGS Publications Warehouse

    Ryden, N.; Park, C.B.; Ulriksen, P.; Miller, R.D.

    2004-01-01

    A multimodal approach to nondestructive seismic pavement testing is described. The presented approach is based on multichannel analysis of all types of seismic waves propagating along the surface of the pavement. The multichannel data acquisition method is replaced by multichannel simulation with one receiver. This method uses only one accelerometer-receiver and a light hammer-source, to generate a synthetic receiver array. This data acquisition technique is made possible through careful triggering of the source and results in such simplification of the technique that it is made generally available. Multiple dispersion curves are automatically and objectively extracted using the multichannel analysis of surface waves processing scheme, which is described. Resulting dispersion curves in the high frequency range match with theoretical Lamb waves in a free plate. At lower frequencies there are several branches of dispersion curves corresponding to the lower layers of different stiffness in the pavement system. The observed behavior of multimodal dispersion curves is in agreement with theory, which has been validated through both numerical modeling and the transfer matrix method, by solving for complex wave numbers. ?? ASCE / JUNE 2004.

  7. MPTD: A Scalable and Flexible Performance Prediction Framework for Parallel Systems

    Microsoft Academic Search

    Chuanfu Xu; Yonggang Che; Zhenghua Wang

    2009-01-01

    The increasing complexities of todays parallel systems pose new challenges for performance prediction. Effective performance\\u000a prediction can provide insight, deepen understanding and further identify potential performance bottlenecks of system\\/application\\u000a combinations. In this paper, we present and evaluate a multi-phase trace-driven (MPTD) performance prediction framework for\\u000a parallel systems. In the trace generation phase, based on a relatively simple performance model, MPTD

  8. Laser Scribing of High-Performance and Flexible Graphene-Based Electrochemical Capacitors

    NASA Astrophysics Data System (ADS)

    El-Kady, Maher F.; Strong, Veronica; Dubin, Sergey; Kaner, Richard B.

    2012-03-01

    Although electrochemical capacitors (ECs), also known as supercapacitors or ultracapacitors, charge and discharge faster than batteries, they are still limited by low energy densities and slow rate capabilities. We used a standard LightScribe DVD optical drive to do the direct laser reduction of graphite oxide films to graphene. The produced films are mechanically robust, show high electrical conductivity (1738 siemens per meter) and specific surface area (1520 square meters per gram), and can thus be used directly as EC electrodes without the need for binders or current collectors, as is the case for conventional ECs. Devices made with these electrodes exhibit ultrahigh energy density values in different electrolytes while maintaining the high power density and excellent cycle stability of ECs. Moreover, these ECs maintain excellent electrochemical attributes under high mechanical stress and thus hold promise for high-power, flexible electronics.

  9. Improving electrochemical performance of flexible thin film electrodes with micropillar array structures

    NASA Astrophysics Data System (ADS)

    Myllymaa, Sami; Pirinen, Sami; Myllymaa, Katja; Suvanto, Mika; Pakkanen, Tapani A.; Pakkanen, Tuula T.; Lappalainen, Reijo

    2012-12-01

    For reliable function, bioelectrodes require a stable, low-impedance contact with the target tissue. In biosignal monitoring applications, in which low ion current densities are recorded, it is important to minimize electrode contact impedances. Recently, several flexible electrode concepts have been introduced for single-patient use. These electrodes conform well on the patient skin enabling an artifact-free, low-noise recording. In this study, polydimethylsiloxane (PDMS) elastomer was used as an electrode substrate material. One half of the substrates were surface-patterned with micropillars produced by using micro-working robot-made mold inserts and a replica molding technique. The substrates were subsequently coated with thin films of titanium (Ti), copper (Cu), silver (Ag) or silver-silver chloride (Ag/AgCl). Electrical impedance spectroscopy studies revealed that the micropillar structure caused statistically significant reductions in impedance modulus and phase for each coating candidate. The relative effect was strongest for pure Ag, for which the values of the real part (Z?) and the imaginary part (Z?) decreased to less than one tenth of the original (smooth) values. However, Ag/AgCl, as expected, proved to be a superior electrode material. Coating with chloride drastically reduced the interfacial impedance compared to pure Ag. Further significant reduction was achieved by the micropillars, since the phase angle declined from 10-13 (for smooth samples, f < 50 Hz) to a value as low as 5. Equivalent circuit modeling was used to obtain a better understanding of phenomena occurring at various electrode-electrolyte interfaces. The knowledge obtained in this study will be exploited in the further development of flexible electrodes and miniaturized biointerfaces with improved electrochemical characteristics.

  10. Taichi-inspired rigid-flexible coupling cellulose-supported solid polymer electrolyte for high-performance lithium batteries

    PubMed Central

    Zhang, Jianjun; Yue, Liping; Hu, Pu; Liu, Zhihong; Qin, Bingsheng; Zhang, Bo; Wang, Qingfu; Ding, Guoliang; Zhang, Chuanjian; Zhou, Xinhong; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

    2014-01-01

    Inspired by Taichi, we proposed rigid-flexible coupling concept and herein developed a highly promising solid polymer electrolyte comprised of poly (ethylene oxide), poly (cyano acrylate), lithium bis(oxalate)borate and robust cellulose nonwoven. Our investigation revealed that this new class solid polymer electrolyte possessed comprehensive properties in high mechanical integrity strength, sufficient ionic conductivity (3 10?4?S cm?1) at 60C and improved dimensional thermostability (up to 160C). In addition, the lithium iron phosphate (LiFePO4)/lithium (Li) cell using such solid polymer electrolyte displayed superior rate capacity (up to 6 C) and stable cycle performance at 80C. Furthermore, the LiFePO4/Li battery could also operate very well even at an elevated temperature of 160C, thus improving enhanced safety performance of lithium batteries. The use of this solid polymer electrolyte mitigates the safety risk and widens the operation temperature range of lithium batteries. Thus, this fascinating study demonstrates a proof of concept of the use of rigid-flexible coupling solid polymer electrolyte toward practical lithium battery applications with improved reliability and safety. PMID:25183416

  11. Taichi-inspired rigid-flexible coupling cellulose-supported solid polymer electrolyte for high-performance lithium batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Jianjun; Yue, Liping; Hu, Pu; Liu, Zhihong; Qin, Bingsheng; Zhang, Bo; Wang, Qingfu; Ding, Guoliang; Zhang, Chuanjian; Zhou, Xinhong; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

    2014-09-01

    Inspired by Taichi, we proposed rigid-flexible coupling concept and herein developed a highly promising solid polymer electrolyte comprised of poly (ethylene oxide), poly (cyano acrylate), lithium bis(oxalate)borate and robust cellulose nonwoven. Our investigation revealed that this new class solid polymer electrolyte possessed comprehensive properties in high mechanical integrity strength, sufficient ionic conductivity (3 10-4 S cm-1) at 60C and improved dimensional thermostability (up to 160C). In addition, the lithium iron phosphate (LiFePO4)/lithium (Li) cell using such solid polymer electrolyte displayed superior rate capacity (up to 6 C) and stable cycle performance at 80C. Furthermore, the LiFePO4/Li battery could also operate very well even at an elevated temperature of 160C, thus improving enhanced safety performance of lithium batteries. The use of this solid polymer electrolyte mitigates the safety risk and widens the operation temperature range of lithium batteries. Thus, this fascinating study demonstrates a proof of concept of the use of rigid-flexible coupling solid polymer electrolyte toward practical lithium battery applications with improved reliability and safety.

  12. Friction evaluation of concrete paver blocks for airport pavement applications

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1992-01-01

    The development and use of concrete paver blocks is reviewed and some general specifications for application of this type of pavement surface at airport facilities are given. Two different shapes of interlocking concrete paver blocks installed in the track surface at NASA Langley's Aircraft Landing Dynamics Facility (ALDF) are described. Preliminary cornering performance results from testing of 40 x 14 radial-belted and bias-ply aircraft tires are reviewed. These tire tests are part of a larger, ongoing joint NASA/FAA/Industry Surface Traction and Radial Tire (START) Program involving several different tire sizes. Both dry and wet surface conditions were evaluated on the two concrete paver block test surfaces and a conventional, nongrooved Portland cement concrete surface. Future test plans involving evaluation of other concrete paver block designs at the ALDF are indicated.

  13. Guide to Cement-Based Integrated Pavement Solutions

    E-print Network

    Conventional Overlays CRCP VIBRATORY COMPACTION Pervious Concrete Full-Depth Reclamation Cement- Treat- ed Base concrete, precast pavements, roller-compacted concrete, cement-treated base, full-depth reclamation, overlays, pervious pavement, roller-compacted concrete, full-depth reclamation, cement-treated base, cement

  14. CHECKLIST FOR INSPECTION OF POROUS PAVEMENTS Location: Inspector

    E-print Network

    for ice management S U Piles of accumulated salt removed in spring S U 2. Debris Cleanup (2-4 times a year minimum, Spring & Fall) Clean porous pavement to remove sediment and organic debris on the pavement available) S U 3. Controlling Run-On (2-4 times a year) Adjacent vegetated areas show no signs of erosion

  15. Research on pavement crack recognition methods based on image processing

    NASA Astrophysics Data System (ADS)

    Cai, Yingchun; Zhang, Yamin

    2011-06-01

    In order to overview and analysis briefly pavement crack recognition methods , then find the current existing problems in pavement crack image processing, the popular methods of crack image processing such as neural network method, morphology method, fuzzy logic method and traditional image processing .etc. are discussed, and some effective solutions to those problems are presented.

  16. TEXAS PAVEMENT PRESERVATION CENTER FOUR-YEAR SUMMARY REPORT

    E-print Network

    Texas at Austin, University of

    TEXAS PAVEMENT PRESERVATION CENTER FOUR-YEAR SUMMARY REPORT Dr. Yetkin Yildirim, P.E., TPPC Director E-mail: yetkin@mail.utexas.edu Mailing address: Texas Pavement Preservation Center Center for Transportation Research The University of Texas at Austin 3208 Red River, CTR 318 Austin, TX 78705 Tel: (512) 232

  17. Cosmogenic 3 He surface-exposure dating of stone pavements

    E-print Network

    Ahmad, Sajjad

    and pedogenic modification of windblown dust. In-situ cosmogenic 3 He surface-exposure ages on volcanic volcanic bedrock, are indistinguishable at the 1 level. We conclude that stone pavements are born of windblown sediments, not deflation or water erosion, is the major agent of pavement evo- lution. According

  18. Improvement of canny algorithm based on pavement edge detection

    Microsoft Academic Search

    Huili Zhao; Guofeng Qin; Xingjian Wang

    2010-01-01

    In this paper we introduce an improved Canny edge detection algorithm and an edge preservation filtering procedure for pavement edge detection applications. Data of pavement images were randomly selected to test this algorithm. There are some problems of Canny operator, unable to detect the weak edge and distinguish the grayscale with little change, the detected edge uncontinuous. Based on these

  19. Strategies for autonomous robots to inspect pavement distresses

    Microsoft Academic Search

    Yuan-Hsu Tseng; Shih-Chung Kang; Jia-Ruey Chang; Cheng-Hao Lee

    2011-01-01

    The distress survey is an important task for pavement maintenance and rehabilitation (M&R) activities. As distress surveys require tremendous human resources, many investigators have begun to develop automatic inspection methods with the aim of increasing the efficiency and accuracy of inspections. After assessment of distress surveys on pavements using an autonomous robot (P3-AT), this research aims at developing motion strategies

  20. Permeable Pavement Research at the Edison Environmental Center

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used permeable pavement systems. Practitioners need additional studies of permeable pavement systems in its intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage conditio...

  1. HEAVY METAL RETENTION WITHIN A POROUS PAVEMENT STRUCTURE

    Microsoft Academic Search

    C. Dierkes; A. Holte; W. F. Geiger

    Porous pavements with reservoir structure for infiltration of runoff from parking spaces and residential streets offer the opportunity to dispose water without using additional space in urban areas. However, pollutants in urban runoff endanger soils and groundwater, when pol- lutant retention in the structure is not sufficient. Porous pavement structures with four differ- ent subbase materials were tested in rigs.

  2. Permeable pavement demonstration site at Edison Environmental Center (Presentation)

    EPA Science Inventory

    There are few studies of full-scale, outdoor, replicated, working pervious pavement systems. More studies of pervious pavement operating in its intended use (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions, and maintenance regimes are necessa...

  3. Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used pervious pavement systems. Practitioners need additional studies of pervious pavement systems in its intended application (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions...

  4. Permeable pavement monitoring at the Edison Environmental Center demonstration site

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used pervious pavement systems. Practitioners need additional studies of pervious pavement systems in its intended application (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions...

  5. COLORADO DEPARTMENT OF TRANSPORTATION Sustainability of Concrete Pavement

    E-print Network

    COLORADO DEPARTMENT OF TRANSPORTATION Sustainability of Concrete Pavement I-225 - Mississippi to 6 · 2 Mile Reconstruction Existing: · 4 Lane Divided Highway · 8" Concrete Pavement (Recycled on-site) · 4" Asphalt Overlay (Recycled off-site) Project Design: · 6 Lane Divided Highway · 13" Concrete

  6. Electro-optical approach to pavement deflection management

    NASA Astrophysics Data System (ADS)

    Rish, Jeff W., III; Adcock, Avery D.; Tuan, Christopher Y.; Baker, Samuel L.; Welker, Hugh W., II; Johnson, Roger F.

    1995-07-01

    A prototype continuous deflection device, referred to as a rolling weight deflectometer (RWD), has been developed as a nondestructive evaluation tool for airfield pavements. The system consists of a rigid trailer equipped with specially designed optical triangulation pavement sensors, a high-speed data acquisition system, and a high-pressure tire/load platform assembly. Pavement sensors are mounted on a rigid box beam equipped with an internal sensor system that corrects, in real time, the relative pavement height position measurements for displacements induced in the beam by mechanical vibrations, changes in temperature, or nonuniform dynamic loads at points where the beam attaches to the frame. The device produces continuous deflection profiles that show pavement response to a moving loaded wheel along the path of travel. These deflection profiles, combined with multiple passes along a lane, provide a far more detailed picture of the pavement structural integrity than has ever before been possible, because existing evaluation tools only produce response information at discrete points. Preliminary results show deflections measured by the RWD are in general agreement with the expected pavement response for various loads. A discussion of the device configuration, preliminary data, and potential as a pavement management tool is presented.

  7. Permeable pavement demonstration at the Edison Environmental Center (Hartford, CT)

    EPA Science Inventory

    In general, there is a lack of full-scale, outdoor, real-world porous pavement studies with system replicates. More studies of porous pavement operating in its intended use (parking lot, roadway, etc.) with climatic events, regular use, and maintenance effects, are necessary. The...

  8. Permeable Pavement Demonstration at the Edison Environmental Center (Hartford)

    EPA Science Inventory

    In general, there is a lack of full-scale, outdoor, real-world porous pavement studies with system replicates. More studies of porous pavement operating in its intended use (parking lot, roadway, etc.) with climatic events, regular use, and maintenance effects, are necessary. The...

  9. Permeable pavement demonstration at the Edison Environmental Center

    EPA Science Inventory

    There are few studies of full-scale, outdoor, replicated, functioning pervious pavement systems. More studies of pervious pavement operating in its intended use (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions, and maintenance regimes are nec...

  10. Characterizing a porous road pavement using surface impedance measurement: A guided numerical inversion procedure.

    PubMed

    Benoit, Galle; Heinkl, Christophe; Gourdon, Emmanuel

    2013-12-01

    This paper deals with a numerical procedure to identify the acoustical parameters of road pavement from surface impedance measurements. This procedure comprises three steps. First, a suitable equivalent fluid model for the acoustical properties porous media is chosen, the variation ranges for the model parameters are set, and a sensitivity analysis for this model is performed. Second, this model is used in the parameter inversion process, which is performed with simulated annealing in a selected frequency range. Third, the sensitivity analysis and inversion process are repeated to estimate each parameter in turn. This approach is tested on data obtained for porous bituminous concrete and using the Zwikker and Kosten equivalent fluid model. This work provides a good foundation for the development of non-destructive in situ methods for the acoustical characterization of road pavements. PMID:25669290

  11. High-performance flexible ultraviolet photoconductors based on solution-processed ultrathin ZnO/Au nanoparticle composite films

    PubMed Central

    Jin, Zhiwen; Gao, Liang; Zhou, Qing; Wang, Jizheng

    2014-01-01

    Transparent ultraviolet (UV) ZnO thin film photoconductors are expected to have great applications in environmental monitoring, large-area displays, and optical communications, and they have drawn enormous interests in recent years. However, at present their performances are not satisfactory: the responsivity R (a parameter characterizing the sensitivity of the device to light) is not high (<1.0 103?AW?1), and the transparency T is not high either (<80%). Realizing high R and high T remains a big challenge today. In this paper, by employing solution-processed ultrathin ZnO/Au nanoparticle composite films, R as high as 1.51 105?AW?1 and T of over 90% are achieved. High values for detectivity D* and linear dynamic range LDR are also obtained, which are 2.05 1015 Jones and 60?dB, respectively. Moreover, such high-performance devices can be fabricated on flexible PET (polyethylene terephthalate) substrates. PMID:24589625

  12. Thin-Pavement Thickness Estimation Using GPR With High-Resolution and Superresolution Methods

    Microsoft Academic Search

    Cdric Le Bastard; Vincent Baltazart; Yide Wang; Joseph Saillard

    2007-01-01

    In the field of civil engineering, sounding the top layer of carriageways, i.e., the pavement layer, is classically performed using standard ground-penetrating radar (GPR), whose resolution is bandwidth dependent. The layer thickness is deduced from both the time delays of backscattered echoes and the known dielectric constant of the medium. This paper focuses on superresolution and high-resolution techniques, which serve

  13. Clogging evaluation of open graded friction course pavements tested under rainfall and heavy vehicle simulators.

    PubMed

    Coleri, Erdem; Kayhanian, Masoud; Harvey, John T; Yang, Kai; Boone, John M

    2013-11-15

    In this study a new procedure is developed to obtain core samples from field sections to assess clogging mechanisms of open graded friction course (OGFC) pavements using X-ray computed tomography (CT) imaging. The approach compared X-ray computed tomography (CT) images taken before and after: (1) rainfall simulations without trafficking to investigate particle-related clogging and (2) full-scale accelerated pavement rutting tests (APT) to investigate deformation related clogging of OGFC layers. Rainfall simulations were performed with runoff water of known total suspended solids (TSS) and particle size distributions (PSDs). Full-scale accelerated rutting tests were performed under controlled temperature and loads. Both investigations were performed for three different OGFC pavements with different layer thicknesses and mix types. The clogging of rutting test sections were also evaluated by comparing the surface permeability measurements performed before and after APT testing. The results of X-ray CT image processing revealed a significant reduction in air-void content of core samples after APT rutting tests. The highest air-void reduction was concentrated at the bottom of the OGFC layers. Permeability measurements also showed a 40%-90% reduction in permeability after APT trafficking. X-ray CT image processing of core samples tested under simulated rainfall showed that air void content reduction is concentrated in the lower part (2-6mm from the bottom) of the OGFC layers as a result of particle accumulation. Small changes in air void contents were observed in the upper part of the OGFC layers (10-15mm) while these reductions in air void contents were not significant to cause surface overflow and hence it is expected that the tested OGFC pavements will have sufficient permeability to infiltrate water during most average storm events. PMID:23920417

  14. Performance and parameter variation of flexible organic thin film transistors in multicomponent organic sensors

    NASA Astrophysics Data System (ADS)

    Stadlober, Barbara; Fian, Alex; Haase, Anja; Kraker, Elke; Zirkl, Martin; Scheipl, Gregor; Jakopic, Georg

    2010-08-01

    Here we report on the fabrication and detailed characterization of flexible low-voltage organic thin-film transistors directly integrated with pyro- and piezoelectric sensors. The functional layer of the capacitive sensors is a ferroelectric fluoropolymer. The transistors on the other hand are based on a high-k nanocomposite gate dielectric and on pentacene as the organic semiconductor and can be operated well below 5V. It is shown, that the transistors can be fabricated on the fluororpolymer layer. Since the control of parameter spread is a very important topic in large area electronics, it was attempted to investigate the homogeneity of a significant set of devices by individual assessment of the layer composition and thickness, the pentacene morphology, the actual geometry and the electrical parameters. It turned out that starting from the measured device parameters such as layer thickness, capacitance, channel dimension, grain size and threshold voltage, the drain current can be calculated with high accuracy in a specified operation point. In addition, it is shown that the main influence on the parameter spread originates from the variations in the threshold voltage. Storage in air destroys the transistors on the long term, whereas bias stress measurements under inert conditions reveal that the interfaces are very stable.

  15. New structural systems for zero-maintenance pavements. Volume 3: Anchored pavement system designed for Edens Expressway

    Microsoft Academic Search

    S. K. Saxena; S. G. Militsopoulos

    1980-01-01

    The response of the Edens Expressway subjected to mechanical and environmental loads using the anchored pavement concept is discussed. The mechanical and thermal properties of materials that could be encountered in future reconstruction of Edens Expressway are presented in a consistent form for computer programming. These properties are viewed as typical design values during investigation of pavement response. The behavior

  16. An analysis of pavement heat flux to optimize the1 water efficiency of a pavement-watering method2

    E-print Network

    Paris-Sud XI, Université de

    heat wave intensity and frequency. However,13 although water consumption necessary to implement; pavement heat flux; pavement-watering; urban heat island; climate change25 adaptation; heat wave26 1. In France and especially Paris, the predicted increases in heat32 wave intensity and frequency due

  17. Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally Graded Viscoelastic Model, Part-I: Development,

    E-print Network

    Paulino, Glaucio H.

    with the collocation method, which leads to an efficient inverse numerical transform procedure. This work is the first to other factors, such as construction practices, aging of materials and temperature dependent material temperatures. In order to perform accurate and efficient analysis and design of asphalt pavement systems

  18. Self-poled transparent and flexible UV light-emitting cerium complex-PVDF composite: a high-performance nanogenerator.

    PubMed

    Garain, Samiran; Sinha, Tridib Kumar; Adhikary, Prakriti; Henkel, Karsten; Sen, Shrabanee; Ram, Shanker; Sinha, Chittaranjan; Schmeier, Dieter; Mandal, Dipankar

    2015-01-21

    Cerium(III)-N,N-dimethylformamide-bisulfate [Ce(DMF)(HSO4)3] complex is doped into poly(vinylidene fluoride) (PVDF) to induce a higher yield (99%) of the electroactive phases (?- and ?-phases) of PVDF. A remarkable enhancement of the output voltage (?32 V) of a nanogenerator (NG) based on a nonelectrically poled cerium(III) complex containing PVDF composite film is achieved by simple repeated human finger imparting, whereas neat PVDF does not show this kind of behavior. This high electrical output resembles the generation of self-poled electroactive ?-phase in PVDF due to the electrostatic interactions between the fluoride of PVDF and the surface-active positive charge cloud of the cerium complex via H-bonding and/or bipolar interaction among the opposite poles of cerium complex and PVDF, respectively. The capacitor charging capability of the flexible NG promises its applicability as piezoelectric-based energy harvester. The cerium(III) complex doped PVDF composite film exhibit an intense photoluminescence in the UV region, which might be due to a participation of electron cloud from negative pole of bipolarized PVDF. This fact may open a new area for prospective development of high-performance energy-saving flexible solid-state UV light emitters. PMID:25523039

  19. Chemically doped three-dimensional porous graphene monoliths for high-performance flexible field emitters

    NASA Astrophysics Data System (ADS)

    Kim, Ho Young; Jeong, Sooyeon; Jeong, Seung Yol; Baeg, Kang-Jun; Han, Joong Tark; Jeong, Mun Seok; Lee, Geon-Woong; Jeong, Hee Jin

    2015-03-01

    Despite the recent progress in the fabrication of field emitters based on graphene nanosheets, their morphological and electrical properties, which affect their degree of field enhancement as well as the electron tunnelling barrier height, should be controlled to allow for better field-emission properties. Here we report a method that allows the synthesis of graphene-based emitters with a high field-enhancement factor and a low work function. The method involves forming monolithic three-dimensional (3D) graphene structures by freeze-drying of a highly concentrated graphene paste and subsequent work-function engineering by chemical doping. Graphene structures with vertically aligned edges were successfully fabricated by the freeze-drying process. Furthermore, their number density could be controlled by varying the composition of the graphene paste. Al- and Au-doped 3D graphene emitters were fabricated by introducing the corresponding dopant solutions into the graphene sheets. The resulting field-emission characteristics of the resulting emitters are discussed. The synthesized 3D graphene emitters were highly flexible, maintaining their field-emission properties even when bent at large angles. This is attributed to the high crystallinity and emitter density and good chemical stability of the 3D graphene emitters, as well as to the strong interactions between the 3D graphene emitters and the substrate.Despite the recent progress in the fabrication of field emitters based on graphene nanosheets, their morphological and electrical properties, which affect their degree of field enhancement as well as the electron tunnelling barrier height, should be controlled to allow for better field-emission properties. Here we report a method that allows the synthesis of graphene-based emitters with a high field-enhancement factor and a low work function. The method involves forming monolithic three-dimensional (3D) graphene structures by freeze-drying of a highly concentrated graphene paste and subsequent work-function engineering by chemical doping. Graphene structures with vertically aligned edges were successfully fabricated by the freeze-drying process. Furthermore, their number density could be controlled by varying the composition of the graphene paste. Al- and Au-doped 3D graphene emitters were fabricated by introducing the corresponding dopant solutions into the graphene sheets. The resulting field-emission characteristics of the resulting emitters are discussed. The synthesized 3D graphene emitters were highly flexible, maintaining their field-emission properties even when bent at large angles. This is attributed to the high crystallinity and emitter density and good chemical stability of the 3D graphene emitters, as well as to the strong interactions between the 3D graphene emitters and the substrate. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07189a

  20. Adaptive Road Crack Detection System by Pavement Classification

    PubMed Central

    Gaviln, Miguel; Balcones, David; Marcos, Oscar; Llorca, David F.; Sotelo, Miguel A.; Parra, Ignacio; Ocaa, Manuel; Aliseda, Pedro; Yarza, Pedro; Amrola, Alejandro

    2011-01-01

    This paper presents a road distress detection system involving the phases needed to properly deal with fully automatic road distress assessment. A vehicle equipped with line scan cameras, laser illumination and acquisition HW-SW is used to storage the digital images that will be further processed to identify road cracks. Pre-processing is firstly carried out to both smooth the texture and enhance the linear features. Non-crack features detection is then applied to mask areas of the images with joints, sealed cracks and white painting, that usually generate false positive cracking. A seed-based approach is proposed to deal with road crack detection, combining Multiple Directional Non-Minimum Suppression (MDNMS) with a symmetry check. Seeds are linked by computing the paths with the lowest cost that meet the symmetry restrictions. The whole detection process involves the use of several parameters. A correct setting becomes essential to get optimal results without manual intervention. A fully automatic approach by means of a linear SVM-based classifier ensemble able to distinguish between up to 10 different types of pavement that appear in the Spanish roads is proposed. The optimal feature vector includes different texture-based features. The parameters are then tuned depending on the output provided by the classifier. Regarding non-crack features detection, results show that the introduction of such module reduces the impact of false positives due to non-crack features up to a factor of 2. In addition, the observed performance of the crack detection system is significantly boosted by adapting the parameters to the type of pavement. PMID:22163717

  1. Developing flexible and high-performance Web servers with frameworks and patterns

    Microsoft Academic Search

    Douglas C. Schmidt; James C. Hu

    2000-01-01

    The goal of this paper is to illustrate how frameworks and patterns address complexities that arise in the design and implementation of high-performance distributed software systems. These complexities are both inherent (e.g., latency reduction and throughput preservation), and accidental (e.g., the continuous reinvention of key concepts and components). This paper explains how complexities occurring in the development of high-performance Web

  2. A review on using crumb rubber in reinforcement of asphalt pavement.

    PubMed

    Mashaan, Nuha Salim; Ali, Asim Hassan; Karim, Mohamed Rehan; Abdelaziz, Mahrez

    2014-01-01

    An immense problem affecting environmental pollution is the increase of waste tyre vehicles. In an attempt to decrease the magnitude of this issue, crumb rubber modifier (CRM) obtained from waste tyre rubber has gained interest in asphalt reinforcement. The use of crumb rubber in the reinforcement of asphalt is considered as a smart solution for sustainable development by reusing waste materials, and it is believed that crumb rubber modifier (CRM) could be an alternative polymer material in improving hot mix asphalt performance properties. In this paper, a critical review on the use of crumb rubber in reinforcement of asphalt pavement will be presented and discussed. It will also include a review on the effects of CRM on the stiffness, rutting, and fatigue resistance of road pavement construction. PMID:24688369

  3. A Review on Using Crumb Rubber in Reinforcement of Asphalt Pavement

    PubMed Central

    Mashaan, Nuha Salim; Ali, Asim Hassan; Karim, Mohamed Rehan; Abdelaziz, Mahrez

    2014-01-01

    An immense problem affecting environmental pollution is the increase of waste tyre vehicles. In an attempt to decrease the magnitude of this issue, crumb rubber modifier (CRM) obtained from waste tyre rubber has gained interest in asphalt reinforcement. The use of crumb rubber in the reinforcement of asphalt is considered as a smart solution for sustainable development by reusing waste materials, and it is believed that crumb rubber modifier (CRM) could be an alternative polymer material in improving hot mix asphalt performance properties. In this paper, a critical review on the use of crumb rubber in reinforcement of asphalt pavement will be presented and discussed. It will also include a review on the effects of CRM on the stiffness, rutting, and fatigue resistance of road pavement construction. PMID:24688369

  4. Use of shredded tires in the subbase layer of asphalt pavements

    SciTech Connect

    Papp, W.J. Jr.; Maher, M.H. [Rutgers Univ., Piscataway, NJ (United States). Dept. of Civil and Environmental Engineering; Baker, R.F. [New Jersey Dept. of Transportation, Trenton, NJ (United States)

    1997-12-31

    Research was conducted on the use of shredded scrap tires for use in the subbase layer of asphalt pavements. Mixtures of shredded scrap tires with virgin soil provide a means of recycling unwanted tires and conserving a finite supply of virgin soil. The mechanistic procedure for the design of pavement systems requires resilient modulus values. Plastic and elastic strains were measured using external LVDT`s and internal proximity sensors. Resilient modulus measurements were conducted on cohesionless soils mixed with various amounts of shredded tire chips. The performance f the shredded tire mixture is compared to that of the naturally occurring virgin soil used in subbase applications in New Jersey. A number of experimental issues are discussed such as: method of compaction, optimum ratio of shredded tire chips to soil, optimum size and gradation of shredded tire chips, and strength testing using California Bearing Ratio.

  5. Solid-state high performance flexible supercapacitors based on polypyrrole-MnO2-carbon fiber hybrid structure.

    PubMed

    Tao, Jiayou; Liu, Nishuang; Ma, Wenzhen; Ding, Longwei; Li, Luying; Su, Jun; Gao, Yihua

    2013-01-01

    A solid-state flexible supercapacitor (SC) based on organic-inorganic composite structure was fabricated through an "in situ growth for conductive wrapping" and an electrode material of polypyrrole (PPy)-MnO2 nanoflakes-carbon fiber (CF) hybrid structure was obtained. The conductive organic material of PPy greatly improved the electrochemical performance of the device. With a high specific capacitance of 69.3?F cm(-3) at a discharge current density of 0.1?A cm(-3) and an energy density of 6.16 10(-3)?Wh cm(-3) at a power density of 0.04?W cm(-3), the device can drive a commercial liquid crystal display (LCD) after being charged. The organic-inorganic composite active materials have enormous potential in energy management and the "in situ growth for conductive wrapping" method might be generalized to open up new strategies for designing next-generation energy storage devices. PMID:23884478

  6. Solid-State High Performance Flexible Supercapacitors Based on Polypyrrole-MnO2-Carbon Fiber Hybrid Structure

    NASA Astrophysics Data System (ADS)

    Tao, Jiayou; Liu, Nishuang; Ma, Wenzhen; Ding, Longwei; Li, Luying; Su, Jun; Gao, Yihua

    2013-07-01

    A solid-state flexible supercapacitor (SC) based on organic-inorganic composite structure was fabricated through an ``in situ growth for conductive wrapping'' and an electrode material of polypyrrole (PPy)-MnO2 nanoflakes-carbon fiber (CF) hybrid structure was obtained. The conductive organic material of PPy greatly improved the electrochemical performance of the device. With a high specific capacitance of 69.3 F cm-3 at a discharge current density of 0.1 A cm-3 and an energy density of 6.16 10-3 Wh cm-3 at a power density of 0.04 W cm-3, the device can drive a commercial liquid crystal display (LCD) after being charged. The organic-inorganic composite active materials have enormous potential in energy management and the ``in situ growth for conductive wrapping'' method might be generalized to open up new strategies for designing next-generation energy storage devices.

  7. Enhanced performance of flexible nanocrystalline silicon thin-film solar cells using seed layers with high hydrogen dilution.

    PubMed

    Lee, Ji-Eun; Kim, Donghwan; Yoon, Kyung Hoon; Cho, Jun-Sik

    2013-12-01

    Flexible hydrogenated nanocrystalline (nc-Si:H) thin-film solar cells were prepared by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD), and the effect of highly crystalline intrinsic Si seed layers at the initial growth stage of i nc-Si:H absorbers on their structural and electrical properties and on the performance of solar cells was investigated. The crystallization of i nc-Si:H absorbers was significantly enforced by the introduction of highly crystalline seed layers, resulting in the reduction of defect-dense a-Si:H grain boundary and incubation layer thickness. The open circuit voltage of the nc-Si:H solar cells with the seed layers was improved by the decrease of charged defect density in the defect-rich amorphous region. PMID:24266159

  8. Solid-State High Performance Flexible Supercapacitors Based on Polypyrrole-MnO2-Carbon Fiber Hybrid Structure

    PubMed Central

    Tao, Jiayou; Liu, Nishuang; Ma, Wenzhen; Ding, Longwei; Li, Luying; Su, Jun; Gao, Yihua

    2013-01-01

    A solid-state flexible supercapacitor (SC) based on organic-inorganic composite structure was fabricated through an in situ growth for conductive wrapping and an electrode material of polypyrrole (PPy)-MnO2 nanoflakes-carbon fiber (CF) hybrid structure was obtained. The conductive organic material of PPy greatly improved the electrochemical performance of the device. With a high specific capacitance of 69.3?F cm?3 at a discharge current density of 0.1?A cm?3 and an energy density of 6.16 10?3?Wh cm?3 at a power density of 0.04?W cm?3, the device can drive a commercial liquid crystal display (LCD) after being charged. The organic-inorganic composite active materials have enormous potential in energy management and the in situ growth for conductive wrapping method might be generalized to open up new strategies for designing next-generation energy storage devices. PMID:23884478

  9. Low-voltage flexible organic electronics based on high-performance sol-gel titanium dioxide dielectric.

    PubMed

    Sung, Sujin; Park, Sungjun; Lee, Won-June; Son, Jongho; Kim, Chang-Hyun; Kim, Yoonhee; Noh, Do Young; Yoon, Myung-Han

    2015-04-15

    In this letter, we report that high-performance insulating films can be generated by judicious control over the microstructure of sol-gel-processed titanium dioxide (TiO2) films, typically known as wide-bandgap semiconductors. The resultant device made of 23 nm-thick TiO2 dielectric layer exhibits a low leakage current density of ?1 10(-7) A cm(-2) at 2 V and a large areal capacitance of 560 nF cm(-2) with the corresponding dielectric constant of 27. Finally, low-voltage flexible organic thin-film transistors were successfully demonstrated by incorporating this versatile solution-processed oxide dielectric material into pentacene transistors on polyimide substrates. PMID:25751669

  10. High-resolution Sensing Sheet for Structural-health Monitoring via Scalable Interfacing of Flexible Electronics with High-performance ICs

    E-print Network

    Electronics with High-performance ICs Yingzhe Hu, Warren Rieutort-Louis, Josue Sanz-Robinson, Katherine Song that combines high-performance ICs with flexible electronics, allowing bonding to such surfaces. The flexi ble to the ICs, allowing many ICs to be intro duced via low-cost sheet lamination for energy-efficient readout

  11. Multiwalled carbon nanotube/polydimethylsiloxane composite films as high performance flexible electric heating elements

    SciTech Connect

    Yan, Jing; Jeong, Young Gyu, E-mail: ygjeong@cnu.ac.kr [Department of Advanced Organic Materials and Textile System Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2014-08-04

    High performance elastomeric electric heating elements were prepared by incorporating various contents of pristine multiwalled carbon nanotube (MWCNT) in polydimethylsiloxane (PDMS) matrix by using an efficient solution-casting and curing technique. The pristine MWCNTs were identified to be uniformly dispersed in the PDMS matrix and the electrical percolation of MWCNTs was evaluated to be at ?0.27?wt.?%, where the electrical resistivity of the MWCNT/PDMS composite films dropped remarkably. Accordingly, the composite films with higher MWCNT contents above 0.3?wt.?% exhibit excellent electric heating performance in terms of temperature response rapidity and electric energy efficiency at constant applied voltages. In addition, the composite films, which were thermally stable up to 250?C, showed excellent heating-cooling cyclic performance, which was associated with operational stability in actual electric heating applications.

  12. Pavement cracking measurements using 3D laser-scan images

    NASA Astrophysics Data System (ADS)

    Ouyang, W.; Xu, B.

    2013-10-01

    Pavement condition surveying is vital for pavement maintenance programs that ensure ride quality and traffic safety. This paper first introduces an automated pavement inspection system which uses a three-dimensional (3D) camera and a structured laser light to acquire dense transverse profiles of a pavement lane surface when it carries a moving vehicle. After the calibration, the 3D system can yield a depth resolution of 0.5 mm and a transverse resolution of 1.56 mm pixel-1 at 1.4 m camera height from the ground. The scanning rate of the camera can be set to its maximum at 5000 lines s-1, allowing the density of scanned profiles to vary with the vehicle's speed. The paper then illustrates the algorithms that utilize 3D information to detect pavement distress, such as transverse, longitudinal and alligator cracking, and presents the field tests on the system's repeatability when scanning a sample pavement in multiple runs at the same vehicle speed, at different vehicle speeds and under different weather conditions. The results show that this dedicated 3D system can capture accurate pavement images that detail surface distress, and obtain consistent crack measurements in repeated tests and under different driving and lighting conditions.

  13. Platypus: Design and Implementation of a Flexible High Performance Object Store

    Microsoft Academic Search

    Zhen He; Stephen M. Blackburn; Luke Kirby; John N. Zigman

    2000-01-01

    This paper reports the design and implementation of Platypus, a trans- actional object store. The twin goals of fle xibility and performance dominate the design of Platypus. The design includes: support for SMP concurrency; stand- alone, client-server and client-peer distribution configurations; configurable log- ging and recovery; and object management which can accommodate garbage col- lection and clustering mechanisms. The first

  14. Flexibly Global? Performing Culture and Identity in an Age of Uncertainty

    ERIC Educational Resources Information Center

    Giardina, Michael D.

    2009-01-01

    Presented as a symbolic interactive messy performance text, Michael Giardina sutures himself into and through the landscape of global social relations, including his own interpretive interactions of disconnection and reconnection with place, home, and nation. In so doing, and in these collages of lived textuality, he examines the complex,

  15. Use of lug anchors to related pavement movement

    NASA Astrophysics Data System (ADS)

    Oakey, S. A.

    1980-04-01

    Minnesota Department of Transporatation's policy is that grades in the 3 to 5 percent and greater range are steep and may require lug anchors. Standard lug anchor spacing varies from 150 feet, center to center, for 3 percent grades to 75 feet, center to center, for 5 percent and greater grades. Conclusions are: (1) that lug anchors do prevent the downhill movement of the concrete pavement; (2) that when lug anchors are used a perforated pipe system also be built to collect the surface water that enters the pavement structure thus eliminating the anticipated base pumping and pavement settlement.

  16. High performance printed N and P-type OTFTs enabling digital and analog complementary circuits on flexible plastic substrate

    NASA Astrophysics Data System (ADS)

    Jacob, S.; Abdinia, S.; Benwadih, M.; Bablet, J.; Chartier, I.; Gwoziecki, R.; Cantatore, E.; van Roermund, A. H. M.; Maddiona, L.; Tramontana, F.; Maiellaro, G.; Mariucci, L.; Rapisarda, M.; Palmisano, G.; Coppard, R.

    2013-06-01

    This paper presents a printed organic complementary technology on flexible plastic substrate with high performance N and P-type Organic Thin Film Transistors (OTFTs), based on small-molecule organic semiconductors in solution. Challenges related to the integration of both OTFT types in a common complementary flow are addressed, showing the importance of surface treatments. Stability on single devices and on an elementary complementary digital circuit (ring oscillator) is studied, demonstrating that a robust and reliable flow with high electrical performances can be established for printed organic devices. These devices are used to manufacture several analog and digital building blocks. The design is carried out using a model specifically developed for this technology, and taking into account the parametric variability. High-frequency measurements of printed envelope detectors show improved speed performance, resulting from the high mobility of the OTFTs. In addition, a compact dynamic flip-flop and a low-offset comparator are demonstrated, thanks to availability of both n-type and p-type OTFTs in the technology. Measurement results are in good agreement with the simulations. The circuits presented establish a complete library of building blocks for the realization of a printed RFID tag.

  17. Numerical analysis of active chordwise flexibility on the performance of non-symmetrical flapping airfoils

    NASA Astrophysics Data System (ADS)

    Tay, W. B.; Lim, K. B.

    2010-01-01

    This paper investigates the effect of active chordwise flexing on the lift, thrust and propulsive efficiency of three types of airfoils. The factors studied are the flexing center location, standard two-sided flexing as well as a type of single-sided flexing. The airfoils are simulated to flap with four configurations, and the effects of flexing under these configurations are investigated. Results show that flexing is not necessarily beneficial for the performance of the airfoils. However, with the correct parameters, efficiency is as high as 0.76 by placing the flexing centre at the trailing edge. The average thrust coefficient is more than twice as high, from 1.63 to 3.57 with flapping and flexing under the right conditions. Moreover, the single-sided flexing also gives an average lift coefficient as high as 4.61 for the S1020 airfoil. The shape of the airfoil does alter the effect of flexing too. Deviating the flexing phase angle away from 90 does not give a significant improvement to the airfoils performance. These results greatly enhance the design of a better performing ornithopter wing.

  18. Effects of a short proprioceptive neuromuscular facilitation stretching bout on quadriceps neuromuscular function, flexibility, and vertical jump performance.

    PubMed

    Place, Nicolas; Blum, Yannick; Armand, Stphane; Maffiuletti, Nicola A; Behm, David G

    2013-02-01

    The inclusion of relatively long bouts of stretching (repeated static stretches of ?30 seconds) in the warm-up is usually associated with a drop in muscle performance. The purpose of this study was to assess the effect of a novel self-administered proprioceptive neuromuscular facilitation (PNF) paradigm with short periods of stretching and contraction on quadriceps neuromuscular function, vertical jump performance, and articular range of motion (ROM). Twelve healthy men (age: 27.7 7.3 years, height: 178.4 10.4 cm, weight: 73.8 16.9 kg) volunteered to participate in a PNF session and a control session separated by 2-7 days. The PNF stretching lasted 2 minutes and consisted of 4 sets of 5-second isometric hamstring contraction immediately followed by 5 seconds of passive static stretch of the quadriceps immediately followed by 5 seconds isometric quadriceps contraction for each leg. For the control session, the participants were asked to walk at a comfortable speed for 2 minutes. Active ROM of knee flexion, vertical jump performance, and quadriceps neuromuscular function were tested before, immediately after, and 15 minutes after the intervention. The PNF stretching procedure did not affect ROM, squat jump, and countermovement jump performances. Accordingly, we did not observe any change in maximal voluntary contraction force, voluntary activation level, M-wave and twitch contractile properties that could be attributed to PNF stretching. The present self-administered PNF stretching of the quadriceps with short (5-second) stretches is not recommended before sports where flexibility is mandatory for performance. PMID:22505131

  19. Mechanical analysis of a mixed mode debonding test for "composite" pavements A. Chabot*, M. Hun, F. Hammoum

    E-print Network

    Paris-Sud XI, Université de

    of UltraThin White-topping pavements (UTW) [1-3] or near reflective cracks of composite pavement [4] during uniformly distributed over a rectangular area at the edge of a joint on an Ultra Thin Whitetopping pavement

  20. Development of a mult-objective strategic management approach to improve decisions for pavement management practices in local agencies

    E-print Network

    Chang Albitres, Carlos Martin

    2009-05-15

    network pavement condition index (PCI), average network remaining life, percent of the pavement network in good condition, and percent of the pavement network in poor and very poor condition. Results from a case study show that funding allocation methods...

  1. Pattern recognition algorithms for density estimation of asphalt pavement during compaction: a simulation study

    NASA Astrophysics Data System (ADS)

    Shangguan, Pengcheng; Al-Qadi, Imad L.; Lahouar, Samer

    2014-08-01

    This paper presents the application of artificial neural network (ANN) based pattern recognition to extract the density information of asphalt pavement from simulated ground penetrating radar (GPR) signals. This study is part of research efforts into the application of GPR to monitor asphalt pavement density during compaction. The main challenge is to eliminate the effect of roller-sprayed water on GPR signals during compaction and to extract density information accurately. A calibration of the excitation function was conducted to provide an accurate match between the simulated signal and the real signal. A modified electromagnetic mixing model was then used to calculate the dielectric constant of asphalt mixture with water. A large database of GPR responses was generated from pavement models having different air void contents and various surface moisture contents using finite-difference time-domain simulation. Feature extraction was performed to extract density-related features from the simulated GPR responses. Air void contents were divided into five classes representing different compaction statuses. An ANN-based pattern recognition system was trained using the extracted features as inputs and air void content classes as target outputs. Accuracy of the system was tested using test data set. Classification of air void contents using the developed algorithm is found to be highly accurate, which indicates effectiveness of this method to predict asphalt concrete density.

  2. Possibilities of ground penetrating radar usage within acceptance tests of rigid pavements

    NASA Astrophysics Data System (ADS)

    Stryk, Josef; Matula, Radek; Pospisil, Karel

    2013-10-01

    Within the road pavement acceptance tests, destructive as well as non-destructive tests of individual road layers are performed to verify the standard requirements. The article describes a method for providing quick, effective and sufficiently accurate measurements of both dowel and tie bar positions in concrete pavements, using a two-channel ground penetrating radar (GPR). Measurements were carried out in laboratory and in-situ conditions. A special hand cart for field measurements, set for the testing requirements, was designed. It was verified that following the correct measuring and assessment method, it is possible to reach accuracy of determining the in-built rebar up to 1 cm in vertical direction and up to 1.5 cm per 11.5 m of measured length in horizontal direction. In the in-situ tests, GPR identification of possible anomalies due to the phase of concrete pavement laying was presented. In the conclusion, a measurement report is mentioned. The standard requirements for the position of dowels and tie bars cover maximum possible deviation of the rebar position from the project documentation in vertical and horizontal direction, maximum deflection of rebar ends to each other, and maximum translation of rebar in the direction of its longitudinal axis.

  3. Laser Scanning on Road Pavements: A New Approach for Characterizing Surface Texture

    PubMed Central

    Bitelli, Gabriele; Simone, Andrea; Girardi, Fabrizio; Lantieri, Claudio

    2012-01-01

    The surface layer of road pavement has a particular importance in relation to the satisfaction of the primary demands of locomotion, such as security and eco-compatibility. Among those pavement surface characteristics, the texture appears to be one of the most interesting with regard to the attainment of skid resistance. Specifications and regulations, providing a wide range of functional indicators, act as guidelines to satisfy the performance requirements. This paper describes an experiment on the use of laser scanner techniques on various types of asphalt for texture characterization. The use of high precision laser scanners, such as the triangulation types, is proposed to expand the analysis of road pavement from the commonly and currently used two-dimensional method to a three-dimensional one, with the aim of extending the range of the most important parameters for these kinds of applications. Laser scanners can be used in an innovative way to obtain information on areal surface layer through a single measurement, with data homogeneity and representativeness. The described experience highlights how the laser scanner is used for both laboratory experiments and tests in situ, with a particular attention paid to factors that could potentially affect the survey. PMID:23012535

  4. Laser scanning on road pavements: a new approach for characterizing surface texture.

    PubMed

    Bitelli, Gabriele; Simone, Andrea; Girardi, Fabrizio; Lantieri, Claudio

    2012-01-01

    The surface layer of road pavement has a particular importance in relation to the satisfaction of the primary demands of locomotion, such as security and eco-compatibility. Among those pavement surface characteristics, the "texture" appears to be one of the most interesting with regard to the attainment of skid resistance. Specifications and regulations, providing a wide range of functional indicators, act as guidelines to satisfy the performance requirements. This paper describes an experiment on the use of laser scanner techniques on various types of asphalt for texture characterization. The use of high precision laser scanners, such as the triangulation types, is proposed to expand the analysis of road pavement from the commonly and currently used two-dimensional method to a three-dimensional one, with the aim of extending the range of the most important parameters for these kinds of applications. Laser scanners can be used in an innovative way to obtain information on areal surface layer through a single measurement, with data homogeneity and representativeness. The described experience highlights how the laser scanner is used for both laboratory experiments and tests in situ, with a particular attention paid to factors that could potentially affect the survey. PMID:23012535

  5. New structural systems for zero-maintenance pavements. Volume 3: Anchored pavement system designed for Edens Expressway

    NASA Astrophysics Data System (ADS)

    Saxena, S. K.; Militsopoulos, S. G.

    1980-08-01

    The response of the Edens Expressway subjected to mechanical and environmental loads using the anchored pavement concept is discussed. The mechanical and thermal properties of materials that could be encountered in future reconstruction of Edens Expressway are presented in a consistent form for computer programming. These properties are viewed as typical design values during investigation of pavement response. The behavior of the anchored pavement under induced temperature loads and weakening of subgrade (by thawing action) is clearly demonstrated. The example problem provides the input parameters of materials and loads for the analysis, the generation of finite element mesh, and the results of the analysis.

  6. Ecological restoration and soil improvement performance of the seabuckthorn flexible dam in the Pisha Sandstone area of Northwestern China

    NASA Astrophysics Data System (ADS)

    Yang, F. S.; Cao, M. M.; Li, H. E.; Wang, X. H.; Bi, C. F.

    2014-09-01

    Soil erosion of the Pisha Sandstone area of Loess Plateau is extremely severe in China. The Pisha Sandstone is very hard when it is dry, while it is very frail when wet. The seabuckthorn flexible dam (SFD), a type of ecological engineering, was proposed to control soil erosion and meliorate soil within the Pisha Sandstone area. To assess its effectiveness and the ecological restoration and soil improvement performance, a field experiment was conducted in this area. We found the strong sediment retention capacity of the SFD is the basis of using it to restore the ecosystem. We compared some certain ecological factors and soil quality between a gully with the SFD and a gully without the SFD, including soil moisture, soil organic matter (SOM), soil nutrients (including Ammonia Nitrogen, available phosphorus and Potassium), vegetation coverage and biodiversity. The results showed that the SFD exhibits excellent performance for ecological restoration and soil improvement of this area. The results are as follows: (i) by the sediment retention action, the deposition commonly occurred in the SFD gully, and the deposition patterns are obviously different from upper to lower gully, (ii) more surprisingly, unlike trees or other shrubs, the seabuckthorn has good horizontal extending capacity by its root system, (iii) soil moisture, SOM, soil nutrients, vegetation coverage and biodiversity in the vegetated gully with the SFD are all markedly increased. The results showed the SFD is both effective and novel biological measure for ecological restoration and soil improvement within the Pisha Sandstone area.

  7. Life cycle assessment of concrete pavements : impacts and opportunities

    E-print Network

    Loijos, Alex (Alexander Nikos)

    2011-01-01

    The concrete pavement network in the United States plays a crucial role in the economy by enabling the transport of people and goods, but it also leads to resource consumption and environmental impacts. This thesis is ...

  8. Regular Inspection and Maintenance Guidance for Porous Pavements

    E-print Network

    year, more frequently for high use sites or sites with higher potential for run- on Vacuum sweeper shall be used regularly to remove sediment and organic debris on the pavement surface. The sweeper may

  9. Roswell International Air Center Airport (ROW) Pavement Condition and Analysis

    E-print Network

    Cal, Mark P.

    Roswell International Air Center Airport (ROW) Pavement Condition and Analysis Submitted to: Jane M ................................................1. Conditions at Roswell International Air Center (ROW) 4 .................................Figure 1. Geographic Location of Roswell International Air Center (ROW) 4 ..............................Table 1

  10. Silver City Grant County Airport (SVC) Pavement Condition and Analysis

    E-print Network

    Cal, Mark P.

    Silver City Grant County Airport (SVC) Pavement Condition and Analysis Submitted to: Jane M. Lucero ....................................1. Airport Conditions at Silver City Grant County Airport (SVC) 4 ..................................Figure 1. Geographic Location of Silver City Grant County Airport (SVC) 4 ......................Table 1

  11. Automated crack control analysis for concrete pavement construction

    E-print Network

    Jang, Se Hoon

    2005-11-01

    The focus of this research is on the control of random cracking in concrete paving by using sawcut notch locations in the early stages of construction. This is a major concern in concrete pavement construction. This research also addresses a...

  12. Variability of hot mix asphalt produced with reclaimed asphalt pavement

    E-print Network

    Yang, Guiqin

    1999-01-01

    of natural resources (aggregate, binder and energy). Adequate techniques to assess the variability of Reclaimed Asphalt Pavement (RAP) are lacking. The objectives of this research are to determine the variabilities of RAP and Hot Mix Asphalt (HMA), determine...

  13. COMPOSITE PORTLAND CEMENT CONCRETE PAVEMENTS (Tollway) Effective: January 30, 2012

    E-print Network

    COMPOSITE PORTLAND CEMENT CONCRETE PAVEMENTS (Tollway) Effective: January 30, 2012 Revised: May 8, 2013 DESCRIPTION This work consists of: 1. Furnishing, mixing, and placing ternary concrete mixes Provision; 2. Supplying and installing all specified reinforcement; 3. Developing concrete mix design

  14. 3-D Seismic Methods for Shallow Imaging Beneath Pavement

    E-print Network

    Miller, Brian

    2013-05-31

    The research presented in this dissertation focuses on survey design and acquisition of near-surface 3D seismic reflection and surface wave data on pavement. Increased efficiency for mapping simple subsurface interfaces through a combined use...

  15. Desert pavement morphology and dynamics, Big Bend National Park, Texas

    E-print Network

    Harmon, Courtney Michelle

    2009-05-15

    set forth in Wood et al. (2002) to classify the desert pavements into surface mosaics based on degree of development. Sediment analysis and soil profile photographs were used to characterize the surface sediments and subsurface soil horizons...

  16. Robotic vehicle mobility and task performance: A flexible control modality for manned systems

    NASA Technical Reports Server (NTRS)

    Eldredge, Frederick

    1994-01-01

    In the early 1980's, a number of concepts were developed for applying robotics to ground systems. The majority of these early application concepts envisioned robotics technology embedded in dedicated unmanned systems; i.e., unmanned systems with no provision for direct manned control of the platform. Although these concepts offered advantages peculiar to platforms designed from the outset exclusively for unmanned operation--i.e., no crew compartment--their findings would require costs and support for a new class of unmanned systems. The current era of reduced budgets and increasing focus on rapid force projection has created new opportunities to examine the value of an alternative concept: the use of existing manned platforms with an ability to quickly shift from normal manned operation to unmanned should a particularly harzardous situation arise. The author of this paper addresses the evolution of robotic vehicle concepts and technology testbeds from exclusively unmanned systems to a variety of 'optionally manned' systems which have been designed with minimum intrusion actuator and control equipment to minimize degradation of vehicle performance in manned modes of operation.

  17. Evaluation of transverse piezoelectric coefficient of ZnO thin films deposited on different flexible substrates: a comparative study on the vibration sensing performance.

    PubMed

    Joshi, Sudeep; Nayak, Manjunatha M; Rajanna, K

    2014-05-28

    We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelectric ZnO thin films deposited on four different flexible substrates for vibration sensing application. The flexible substrates employed for present experimental study were namely a metal alloy (Phynox), metal (aluminum), polyimide (Kapton), and polyester (Mylar). ZnO thin films were deposited by an RF reactive magnetron sputtering technique. ZnO thin films of similar thicknesses of 700 30 nm were deposited on four different flexible substrates to have proper comparative studies. The crystallinity, surface morphology, chemical composition, and roughness of ZnO thin films were evaluated by respective material characterization techniques. The transverse piezoelectric coefficient (d31) value for assessing the piezoelectric property of ZnO thin films on different flexible substrates was measured by a four-point bending method. ZnO thin films deposited on Phynox alloy substrate showed relatively better material characterization results and a higher piezoelectric d31 coefficient value as compared to ZnO films on metal and polymer substrates. In order to experimentally verify the above observations, vibration sensing studies were performed. As expected, the ZnO thin film deposited on Phynox alloy substrate showed better vibration sensing performance. It has generated the highest peak to peak output voltage amplitude of 256 mV as compared to that of aluminum (224 mV), Kapton (144 mV), and Mylar (46 mV). Therefore, metal alloy flexible substrate proves to be a more suitable, advantageous, and versatile choice for integrating ZnO thin films as compared to metal and polymer flexible substrates for vibration sensing applications. The present experimental study is extremely important and helpful for the selection of a suitable flexible substrate for various applications in the field of sensor and actuator technology. PMID:24773266

  18. Temporary bond-debond process for manufacture of flexible electronics: Impact of adhesive and carrier properties on performance

    NASA Astrophysics Data System (ADS)

    Haq, Jesmin; Ageno, Scott; Raupp, Gregory B.; Vogt, Bryan D.; Loy, Doug

    2010-12-01

    Manufacturing of microelectronics on flexible substrates is challenged by difficulties in maintaining alignment and conformity of the substrate through deposition, patterning, and etch processes. To address these difficulties, a temporary bond-debond method has been developed for effective automated handling of flexible substrate systems during electronics fabrication. The flexible substrate is temporarily bonded to a rigid carrier, which provides structural support and suppresses bending during processing. The photolithographic alignment of the bonded system is strongly dependent upon the viscoelastic properties of the bonding adhesive. An additional challenge is to control the stress developed during processing; these stresses evolve predominately through thermomechanical property mismatches between the carrier and flexible substrate. To investigate the role of the thermomechanical properties of the carrier and adhesive, the stress, and subsequent bowing of bonded systems (flexible substrate-adhesive-carrier) is examined systematically using different carriers and adhesives. Excellent registration of the flexible circuitry fabricated on the bonded system with low stress can be achieved by using a viscoelastic adhesive with a low loss factor (tan ?) and a carrier with high modulus and coefficient of thermal expansion that is closely matched to the flexible substrate. This bond-debond process enables the high yield fabrication of flexible microelectronics on plastic substrates.

  19. Strategies for autonomous robot to inspect pavement distresses

    Microsoft Academic Search

    Y. H. Tseng; S. C. Kang; Y. S. Su; C. H. Lee; J. R. Chang

    2010-01-01

    Distress inspection is an important task in pavement maintenance. Pavement inspection requires tremendous human resources, so many investigators start developing automatic and robotic inspection methods to increase the efficiency and accuracy. However, the systems they developed are applicable for network-level inspection (large areas, long-distance) but too expensive or too big for project-level inspection (small areas, short-distance). Dealing with this problem,

  20. Preventive Maintenance Condition Standards of Expressway Asphalt Pavement

    Microsoft Academic Search

    Hu Guoxiang; Li Jie

    2009-01-01

    There isn't a unified pavement preventive maintenance road condition standard both at home and abroad till now, in view of that, macro and micro road condition standard for expressway asphalt pavement preventive maintenance is established, among which macro standard is under the promise of PSSIges83, and is under the control standard of 82lesPCI<88, 88lesRQI<93, 85lesSRI<90. Its determinative process, the usage

  1. Rehabilitation of continuously reinforced concrete pavements using overlays

    E-print Network

    Sriraman, Soumya

    1993-01-01

    was actually experienced. Any rehabilitation alternative being considered must, hence be able to meet the design requirements and not fail during its design life. Rigid overlays provide a feasible option in terms of strength and longevity. For a nation... whose network of pavements is now in need of rehabilitation, CRC pavements present themselves as a very feasible and lucrative option, if life-cycle costs were the basis of design. If designed and constructed properly, CRC overlays can serve...

  2. Assessing the improved performance of freestanding, flexible graphene and carbon nanotube hybrid foams for lithium ion battery anodes

    NASA Astrophysics Data System (ADS)

    Cohn, Adam P.; Oakes, Landon; Carter, Rachel; Chatterjee, Shahana; Westover, Andrew S.; Share, Keith; Pint, Cary L.

    2014-04-01

    We demonstrate the fabrication of three-dimensional freestanding foams of hybrid graphene-single-walled carbon nanotube nanomanufactured materials with reversible capacities of 2640 mA h g-1 at 0.186 A g-1 and 236 mA h g-1 at 27.9 A g-1. The Li storage behavior of this material is compared against other nanostructures in similar flexible foam platforms including graphene, ultra-thin graphite, and single-walled carbon nanotubes (SWNTs), and we elucidate the improved hybrid material performance due to the decoupling of lithium storage reaction energetics dictated by the SWNTs from the total storage capacity of the hybrid material. This work demonstrates a route to develop mechanically robust all-carbon electrodes with the potential for reversible Li-ion storage capacity approaching silicon, power capability of the best supercapacitors, and based on a material simultaneously usable as a charge collector and anode.We demonstrate the fabrication of three-dimensional freestanding foams of hybrid graphene-single-walled carbon nanotube nanomanufactured materials with reversible capacities of 2640 mA h g-1 at 0.186 A g-1 and 236 mA h g-1 at 27.9 A g-1. The Li storage behavior of this material is compared against other nanostructures in similar flexible foam platforms including graphene, ultra-thin graphite, and single-walled carbon nanotubes (SWNTs), and we elucidate the improved hybrid material performance due to the decoupling of lithium storage reaction energetics dictated by the SWNTs from the total storage capacity of the hybrid material. This work demonstrates a route to develop mechanically robust all-carbon electrodes with the potential for reversible Li-ion storage capacity approaching silicon, power capability of the best supercapacitors, and based on a material simultaneously usable as a charge collector and anode. Electronic supplementary information (ESI) available: ESI is available that includes (i) SEM and photographs of ultra-thin graphite foams, (ii) Raman spectra from SWNT and ultrathin graphite foams, (iii) CV measurements at higher scan rates, (iv) comparison of discharge characteristics of first, second, and 300th discharge, (v) Ragone plot showing power-energy characteristics of hybrid graphene-SWNT electrodes, and (vi) TEM images of multilayered graphene edges from graphene and graphene-SWNT hybrids, with interlayer spacing maps and FFT analysis. See DOI: 10.1039/c4nr00390j

  3. GPR abilities in investigation of the pavement transversal cracks

    NASA Astrophysics Data System (ADS)

    Krysi?ski, Lech; Sudyka, Jacek

    2013-10-01

    This paper describes the results of an investigation into the capabilities of the GPR technique within the field of pavement crack diagnostics. Initially, laboratory tests were performed on prototypes simulating idealized cracks. Next, long-term visual observation and repeated GPR scanning were performed, on three roads of semi-rigid construction, several hundreds of meters long and subjected to heavy traffic. Furthermore, a road of rigid construction was tested, having a more than 70-year history of use. In several cases the cracks were probed by drillings, in order to recognize structures responsible for signal generation, or to explain reasons of signal lacking. The main result of this work is a list of GPR indications of cracks, which can be noticed on echograms. It was created through a correlation of the visually-observed cracks with the corresponding echograms, with decimeter accuracy. Several types of GPR responses were classified and linked to possible categories of crack structures, or to processes associated with the presence of cracks (as crumbling, erosion, and lithological alterations). The poor visibility of cracks was also studied, due to small crack size, or to the blurred character of the damaged area, or else to masking effects related to coarse grains in the asphalt mixture. The efficiency of the proposed method for the identification and localization of cracks is higher when a long-term GPR observation is performed.

  4. Flexible asymmetric supercapacitors based on ultrathin two-dimensional nanosheets with outstanding electrochemical performance and aesthetic property

    PubMed Central

    Shi, Shan; Xu, Chengjun; Yang, Cheng; Chen, Yanyi; Liu, Juanjuan; Kang, Feiyu

    2013-01-01

    Flexible asymmetric supercapacitors with excellent electrochemical performance and aesthetic property are realized by using ultrathin two-dimensional (2D) MnO2 and graphene nanosheets as cathode and anode materials, respectively. 2D MnO2 nanosheets (MSs) with a thickness of ca. 2?nm are synthesized with a soft template method for the first time, which achieve a high specific capacitance of 774?F g?1 even after 10000 cycles. Asymmetric supercapacitors based on ultrathin MSs and graphene exhibit a very high energy density up to 97.2?Wh kg?1 with no more than 3% capacitance loss after 10000 cycles in aqueous electrolyte. Most interestingly, we show that the energy storage device can have an aesthetic property. For instance, a Chinese panda supercapacitor is capable of lighting up a red light emitting diode. This work has another, quite different aspect that a supercapacitor is no longer a cold industry product, but could have the meaning of art. PMID:24008931

  5. Recycling of plastic and rubber tire waste in asphalt pavements

    SciTech Connect

    Morrison, G.R.; Lee, N.K.; Hesp, S.A.M. [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Chemistry

    1994-12-31

    This paper discusses some important issues related to the use of recycled thermoplastics and rubber tire waste in asphalt binders for hot-mix pavements. Both high temperature rheological and low temperature fracture studies are presented on recycled polyethylene, devulcanized and crumb rubber-modified asphalt binders. The results are compared to unmodified and commercially available modified binders. This research is especially timely in light of the US Intermodal Surface Transportation Efficiency Act of 1991, Section 1038 which, starting in 1995, will force state and local governments to use significant amounts of recycled rubber tire or plastic waste in federally funded highway projects. High temperature rheological measurements of the loss modulus, loss tangent and complex modulus show a significant improvement when only small quantities of crumb rubber, devulcanized crumb rubber or waste polyethylene are added to the asphalt binders. The low temperature fracture performance of the modified asphalts is greatly influenced by the interfacial strength between the dispersed and continuous phase. The fracture toughness increases dramatically, only when low molecular weight polymers are grafted in-situ onto the rubber and polymer dispersed phases in order to strength the interface. This points to a crack-pinning mechanism as being responsible for the dramatic increase in fracture toughness that is observed in this work. Single phase, devulcanized crumb rubber-asphalt systems perform quite poorly at low temperatures.

  6. Flexible Sigmoidoscopy

    MedlinePLUS

    ... colon. Flexible sigmoidoscopy can show irritated or swollen tissue, ulcers, and polypsextra pieces of tissue that grow ... colon. Flexible sigmoidoscopy can show irritated or swollen tissue, ulcers, and polypsextra pieces of tissue that grow ...

  7. Over the Edge and Back: What to Do If You Drive Off the Pavement Edge

    MedlinePLUS

    AAA Foundation for Traffic Safety Over the Edge and Back What to do if you drive off ... fatal relative to other crashes on similar roads. AAA Foundationfor Traffic Safety Pavement edge drop-off Pavement ...

  8. Determination of the Presence Conditions of Pavement Markings using Image Processing

    E-print Network

    Ge, Hancheng

    2012-10-19

    Pavement markings, as a form of traffic control devices, play a crucial role in safely guiding drivers. Restriping pavement markings is an important task in the maintenance of traffic control devices. Every year state agencies spend a lot of money...

  9. Evaluation of Three Porous Pavement Systems in a Newly Constructed Parking Lot

    EPA Science Inventory

    This project examines porous pavement systems in a newly constructed parking lot next to Building 205 at the Edison Environmental Center. Porous pavement systems are one means of promoting environmental sustainability through stormwater runoff reduction. This project examines t...

  10. POROUS PAVEMENT PHASE I DESIGN AND OPERATIONAL CRITERIA (EPA/600/2-80/135)

    EPA Science Inventory

    Design and operational criteria, utilization concepts, benefits and disadvantages, as well as other characteristics of porous pavements are presented in this report. Particular emphasis is placed on porous asphalt pavements, but the criteria and design approach are applicable to ...

  11. Experimental Study on Geocell-Reinforced Flexible Pavements with Recycled Asphalt Pavement (RAP) Bases under Cyclic Loading

    E-print Network

    Acharya, Bhagaban

    2011-12-31

    shear test, light weight deflectometer test, and dynamic cone penetration test for consistency. Earth pressure cells were placed at the interface between subgrade and base to measure the vertical stresses applied on the subgrade. Tell tales were placed...

  12. On-site inspections of pavement damages evolution using GPR

    NASA Astrophysics Data System (ADS)

    Tosti, Fabio; D'Amico, Fabrizio; Calvi, Alessandro; Benedetto, Andrea

    2014-05-01

    Ground-penetrating radar (GPR) is being increasingly used for pavements maintenance due to the wide range of applications spanning from physical to geometrical inspections, thereby allowing for a reliable diagnosis of the main causes of road structural damages. In this work, an off-ground GPR system was used to investigate a large-scale rural road network. Two sets of surveys were carried out in different time periods, with the main goals to i) localize the most critical sections; ii) monitor the evolution of previous damages and localize newborn deep faults, although not revealed at the pavement surface level; iii) analyze the causes of both evolution and emergence of faults by considering environmental and human factors. A 1-GHz GPR air-launched antenna was linked to an instrumented van for collecting data at traffic speed. Other support techniques (e.g. GPS data logger, odometer, HD video camera) were used for cross-checking,. Such centre frequency of investigation along with a 25-ns time window allow for a signal penetration of 900 mm, consistent with the deepest layer interfaces. The bottom of the array was 400 mm over the surface, with a minimum distance of 1200 mm from the van body. Scan length of maximum 10 km were provided for avoiding heavy computational loads. The rural road network was located in the District of Rieti, 100 km north from Rome, Italy, and mostly develops in a hilly and mountainous landscape. In most of the investigated roads, the carriageway consists in two lanes of 3.75 meters wide and two shoulders of 0.50 meters wide. A typical road section includes a HMA layer (65 mm average thickness), a base layer (100 mm average thickness), and a subbase layer (300 mm average thickness), as described by pavement design charts. The first set of surveys was carried out in two days at the beginning of spring in moderately dry conditions. Overall, 320-km-long inspections were performed in both travel directions, thereby showing a productivity of approximately 160 km/day at 40 km/h speed, on the average. After processing and first-checking, GPR profiles were divided into homogeneous sections according to the combination of different parameters (e.g. route analyzed, long distance conditions of regularity/irregularity in layers arrangement). In such context, a high consistency between surface damages, mismatches from the GPR scans, and boundary environmental conditions was demonstrated. In addition, deep mismatches were detected even for early-stage or unrevealed faults. The second set of surveys was carried out in autumn in high humidity conditions, due to recent rainfalls. 160 km of relevant routes from the same road network were investigated. Results showed a high consistency with those collected during the first-stage of surveys. Minor changes were found in those sections with low traffic loads (e.g. farther away from the biggest town of Rieti), whereas major mismatches were detected in wetlands (e.g. close to rivers), work zones, and nearby those sections already deeply damaged in the past. This work benefited from networking activities carried out within the EU funded COST Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar'.

  13. Characterization of cementitiously stabilized subgrades for mechanistic-empirical pavement design

    NASA Astrophysics Data System (ADS)

    Solanki, Pranshoo

    Pavements are vulnerable to subgrade layer performance because it acts as a foundation. Due to increase in the truck traffic, pavement engineers are challenged to build more strong and long-lasting pavements. To increase the load-bearing capacity of pavements, subgrade layer is often stabilized with cementitious additives. Thus, an overall characterization of stabilized subgrade layer is important for enhanced short- and long-term pavement performance. In this study, the effect of type and amount of additive on the short-term performance in terms of material properties recommended by the new Mechanistic-Empirical Pavement Design Guide (MEPDG) is examined. A total of four soils commonly encountered as subgrades in Oklahoma are utilized. Results show that the changes in the Mr, ME and UCS values stabilized specimens depend on the soil type and properties of additives. The long-term performance (or durability) of stabilized soil specimens is investigated by conducting freeze-thaw (F-T) cycling, vacuum saturation and tube suction tests on 7-day cured P-, K- and C-soil specimens stabilized with 6% lime, 10% CFA and 10% CKD. This study is motivated by the fact that during the service life of pavement stabilized layers are subjected to F-T cycles and moisture variations. It is found that that UCS value of all the stabilized specimens decreased with increase in the number of F-T cycles. A strong correlation was observed between UCS values retained after vacuum saturation and F-T cycles indicating that vacuum saturation could be used as a time-efficient and inexpensive method for evaluating durability of stabilized soils. In this study, short- and long-term observations from stabilization of sulfate bearing soil with locally available low (CFA), moderate (CKD) and high (lime) calcium-based stabilizers are determined to evaluate and compare the effect of additive type on the phenomenon of sulfate-induced heave. The impact of different factors on the development of the ettringite, responsible for sulfate-induced heaving, is also discussed. For Level 2 design of pavements, a total of four stress-based statistical models and two feed-forward-type artificial neural network (ANN) models, are evaluated for predicting resilient modulus of 28-day cured stabilized specimens. Specifically, one semi-log stress-based, three log-log stress-based, one Multi-Layer Perceptrons Network (MLPN), and one Radial Basis Function Network (RBFN) are developed. Overall, semi-log stress-based and MLPN neural network are found to show best acceptable performance for the present evaluation and validation datasets. Further, correlations are presented for stress-based models to correlate Mr with compacted specimen characteristics and soil/additive properties. Additionally, the effect of type of additive on indirect tensile and fatigue characteristics of selected stabilized P- and V-soil is evaluated. This study is based on the fact that stabilized layer is subjected to tensile stresses under wheel loading. Thus, the resilient modulus in tension (M rt), fatigue life and strength in tension (sigmat) or flexure (represented by modulus of rupture, MOR) becomes another important design parameter within the mechanistic framework. Cylindrical specimens are prepared, cured for 28 days and subjected to different stress sequences in indirect tension to study the Mrt. On the other hand, stabilized beam specimens are compacted using a Linear Kneading Compactor and subjected to repeated cycles of reloading-unloading after 28 days of curing in a four-point beam fatigue apparatus for evaluating fatigue life and flexural stiffness. It is found that all three additives improved the Mrt, sigmat and MOR values; however, degree of improvement varied with the type of additive and soil. This study encompasses the differences in the design of semi-rigid pavements developed using AASHTO 1993 and AASHTO 2002 MEPDG methodologies. Further, the design curves for fatigue performance prediction of stabilized layers are developed for different stabilized pavement sections. Knowledge gained f

  14. of Transportation Rigid Pavement Design and Analysis Web-Based Training Site

    E-print Network

    Texas at Austin, University of

    Texas Department of Transportation Rigid Pavement Design and Analysis Web-Based Training Site Highway Administration Texas Department of Transportation, 2004 Rigid Pavement Design and Analysis Web for six computer programs pertaining mainly to the design and analysis of rigid pavements. The programs

  15. Project Information Form Project Title White Paper on The application of permeable pavement with emphasis

    E-print Network

    California at Davis, University of

    Project Information Form Project Title White Paper on The application of permeable pavement (by each agency or organization) Cal Trans Total Project Cost $29,007 Agency ID or Contract Number Project Depending on the type of surface pavement, permeable pavement can be termed as porous asphalt

  16. Concrete Pavement I-285 under 5th runway at Hartsfield Jackson

    E-print Network

    Concrete Pavement Sweet as a James Page I-285 under 5th runway at Hartsfield Jackson International Concrete Paving project I-285 East Perimeter Fiscal 2012 GDOT placed 205,704 square yards of RCC Pavement Portland Cement Concrete Pavement State Route 96 Crawford / Peach Counties I-75 Tift County CRC Lane

  17. Fast process to decorate silver nanoparticles on carbon nanomaterials for preparing high-performance flexible transparent conductive films.

    PubMed

    Li, Yu-An; Chen, Yin-Ju; Tai, Nyan-Hwa

    2013-07-01

    This work demonstrates a fast process to decorate silver (Ag) nanoparticles onto the functionalized few-walled carbon nanotubes (f-FWCNTs) and graphene nanosheets (f-GNs). The Ag-coated carbon nanomaterials were used as fillers, which mixed with poly(3,4-ethylenedioxythiophene)-poly(4-stryensulfonate) (PEDOT:PSS) for preparing high optoelectronic performances of flexible transparent conductive films (TCFs). The Ag nanoparticles with a particle size of approximate 5 nm were uniformly distributed on the surfaces of the f-FWCNTs (Ag@f-FWCNTs) and the f-GNs (Ag@f-GNs). The Ag ions play the role of electron acceptors during the reduction process, which increases the hole concentrations in PEDOT:PSS, f-FWCNTs, and f-GNs, therefore enhancing the electrical conductivity of the TCFs. Additionally, the Schottky barrier was decreased because of the increase of work functions of the carbon fillers caused by Ag decoration. The X-ray diffraction spectrum of Ag@f-GNs depicts the formations of the face-centered cubic Ag nanoparticles, and the peak of the (002) graphene plane slightly shifted to the lower frequency, indicating that the f-GN interlayer was intercalated with Ag ions or Ag nanoparticles. When the mixture of 2.0 wt % Ag@f-FWCNTs and 8.0 wt % Ag@f-GNs containing PEDOT:PSS dispersant was coated onto a poly(ethylene terephthalate) (PET) substrate, outstanding optoelectronic properties with a sheet resistance of 50.3 ?/sq and a transmittance of 79.73% at a wavelength of 550 nm were achieved. PMID:23758652

  18. Insights into mechanical compression and the enhancement in performance by Mg(OH)2 coating in flexible dye sensitized solar cells.

    PubMed

    Peiris, T A Nirmal; Wijayantha, K G Upul; Garca-Caadas, Jorge

    2014-02-21

    The engineering of flexible dye sensitized solar cells (DSCs) by mechanical compression is one of the methods that allow low temperature processing of these devices. However, suppressing the high temperature sintering process also significantly reduces the performance of the cells. In our previous work [J. Phys. Chem. C, 2012, 116, 1211], we have attempted to improve flexible DSC performance by coating the porous TiO2 photoanode with an electrodeposited Mg(OH)2 layer. In that work, we have obtained one of the highest photovoltages reported to date in flexible DSCs (847 mV). In order to gain more insights into the reasons for both poorer performance of compressed cells and the origin of the voltage enhancement achieved by the Mg(OH)2 coating, here we present an in-depth study by means of electrochemical impedance spectroscopy, Mott-Schottky plots analysis and open-circuit voltage decays. The existence of a shunt resistance in the mechanically compressed cells is revealed, causing an additional drawback to the poor inter-particle necking. By introducing the Mg(OH)2 coating the recombination in the cell becomes significantly reduced, being the key reason which is responsible for the higher photovoltage. Additionally, the coating and the compression cause modifications in the surface states and in the nature of the interfaces with the electrolyte. This induces TiO2 conduction band displacements and shifts of the relative position of the modified states that influence the performance. PMID:24424329

  19. Design of a flexible high performance quadcopter platform breaking the MAV endurance record with laser power beaming

    Microsoft Academic Search

    Michael C. Achtelik; Jan Stumpf; Daniel Gurdan; Klaus-Michael Doth

    2011-01-01

    In this paper we present the design of a highly flexible quadcopter platform and the software tools used in an example experiment to show unlimited flight time of an MAV with laser power beaming. We describe the mechanical design as well as the flight control system architecture which are focused on easy adaption to a wide variety of experiments. The

  20. Design and implementation of PAVEMON: A GIS web-based pavement monitoring system based on large amounts of heterogeneous sensors data

    NASA Astrophysics Data System (ADS)

    Shahini Shamsabadi, Salar

    A web-based PAVEment MONitoring system, PAVEMON, is a GIS oriented platform for accommodating, representing, and leveraging data from a multi-modal mobile sensor system. Stated sensor system consists of acoustic, optical, electromagnetic, and GPS sensors and is capable of producing as much as 1 Terabyte of data per day. Multi-channel raw sensor data (microphone, accelerometer, tire pressure sensor, video) and processed results (road profile, crack density, international roughness index, micro texture depth, etc.) are outputs of this sensor system. By correlating the sensor measurements and positioning data collected in tight time synchronization, PAVEMON attaches a spatial component to all the datasets. These spatially indexed outputs are placed into an Oracle database which integrates seamlessly with PAVEMON's web-based system. The web-based system of PAVEMON consists of two major modules: 1) a GIS module for visualizing and spatial analysis of pavement condition information layers, and 2) a decision-support module for managing maintenance and repair (M?) activities and predicting future budget needs. PAVEMON weaves together sensor data with third-party climate and traffic information from the National Oceanic and Atmospheric Administration (NOAA) and Long Term Pavement Performance (LTPP) databases for an organized data driven approach to conduct pavement management activities. PAVEMON deals with heterogeneous and redundant observations by fusing them for jointly-derived higher-confidence results. A prominent example of the fusion algorithms developed within PAVEMON is a data fusion algorithm used for estimating the overall pavement conditions in terms of ASTM's Pavement Condition Index (PCI). PAVEMON predicts PCI by undertaking a statistical fusion approach and selecting a subset of all the sensor measurements. Other fusion algorithms include noise-removal algorithms to remove false negatives in the sensor data in addition to fusion algorithms developed for identifying features on the road. PAVEMON offers an ideal research and monitoring platform for rapid, intelligent and comprehensive evaluation of tomorrow's transportation infrastructure based on up-to-date data from heterogeneous sensor systems.

  1. Development of equations to determine the increase in pavement condition due to treatment and the rate of decrease in condition after treatment for a local agency pavement network.

    E-print Network

    Deshmukh, Maithilee Mukund.

    2010-07-14

    DEVELOPMENT OF EQUATIONS TO DETERMINE THE INCREASE IN PAVEMENT CONDITION DUE TO TREATMENT AND THE RATE OF DECREASE IN CONDITION AFTER TREATMENT FOR A LOCAL AGENCY PAVEMENT NETWORK A Thesis by MAITHILEE MUKUND DESHMUKH Submitted... CONDITION DUE TO TREATMENT AND THE RATE OF DECREASE IN CONDITION AFTER TREATMENT FOR A LOCAL AGENCY PAVEMENT NETWORK A Thesis by MAITHILEE MUKUND DESHMUKH Submitted to the Office of Graduate Studies of Texas A&M University in partial...

  2. Desert pavements and associated rock varnish in the Mojave Desert: How old can they be?

    NASA Astrophysics Data System (ADS)

    Quade, Jay

    2001-09-01

    Desert pavements are common features of arid landscapes and have been widely used as a relative age indicator of the geomorphic surfaces upon which they are developed. In this study I examined the patterns of pavement development as a function of elevation in the Mojave Desert as well as the causes for the gradual disappearance of pavement at high elevations. Pavement density, as measured by percentage of pebble coverage, decreases systematically with elevation gain by 3% per 100 m, from 95% coverage below 500 m to less than 60% at 1700 m. Plants appear to be the main agent of pavement disruption; plant density decreases as pavement density increases. Burrowing by rodents and crusting by cryptobiota also disrupt pavement development at higher elevation. During the last glacial maximum, plant communities were displaced 1000 1400 m downward in the Mojave Desert. Pavements today generally do not survive above the blackbush (Coleogyne ramossisma)-sagebrush (Artemisia tridentata) zone. Evidence from packrat middens shows that these and other plants typical of high elevations today grew as low as 300 400 m during the last glacial maximum. I suggest that during the last glacial maximum, desert pavements were confined to the lowest alluvial fans of Death Valley and adjoining low valleys. No alluvial desert pavements above 400 m in the region are older than the latest Pleistocene. By the same reasoning, desert varnish on desert pavements above 400 m may all be Holocene in age, except where developed on stable boulders.

  3. Vibration of vehicle-pavement coupled system based on a Timoshenko beam on a nonlinear foundation

    NASA Astrophysics Data System (ADS)

    Ding, Hu; Yang, Yan; Chen, Li-Qun; Yang, Shao-Pu

    2014-12-01

    This paper focuses on the coupled nonlinear vibration of vehicle-pavement system. The pavement is modeled as a Timoshenko beam resting on a six-parameter foundation. The vehicle is simplified as a spring-mass-damper oscillator. For the first time, the dynamic response of vehicle-pavement coupled system is studied by modeling the pavement as a Timoshenko beam resting on a nonlinear foundation. Consequently, the shear effects and the rotational inertia of the pavement are included in the modeling process. The pavement model is assumed to be a linear-plus-cubic Pasternak-type foundation. Furthermore, the convergent Galerkin truncation is used to obtain approximate solutions to the coupled vibratory response of the vehicle-pavement coupled system. The dynamic responses of the vehicle-pavement system with the asphalt pavement on soft soil foundation are investigated via the numerical examples. The numerical results show that the calculation for the coupled vibratory response needs high-order modes. Moreover, the coupling effects between the pavement and the vehicle are numerically examined by using the convergent modal truncation. The physical parameters of the vehicle-pavement system such as the shear modulus are compared for determining their influences on the coupled vibratory response.

  4. Impact of compressed natural gas fueled buses on street pavements

    SciTech Connect

    Yang, D.; Harrison, R.

    1995-07-01

    Capital Metro, the Ausin, Texas transit authority, is currently evaluating a number of CNG fueled buses. As part of the U.S. DOT Region Six University Transportation Centers Program (UTCP), a study was instigated into the scale of incremental pavement consumption associated with the operation of these buses. The study suggests that replacing current vehicles with CNG powered models utilizing aluminum storage tanks would raise average network equivalent single rehabilitation costs across the network of over four percent. Finally, it recommends that full cost study be undertaken with evaluation of the adoption of alternative bus fuels - which includes pavement and environmental impacts.

  5. Evaluation of Multilayered Pavement Structures from Measurements of Surface Waves

    NASA Astrophysics Data System (ADS)

    Ryden, Nils; Lowe, Michael J. S.; Cawley, Peter; Park, Choon B.

    2006-03-01

    A method is presented for evaluating the thickness and stiffness of multilayered pavement structures from guided waves measured at the surface. Data is collected with a light hammer as the source and an accelerometer as receiver, generating a synthetic receiver array. The top layer properties are evaluated with a Lamb wave analysis. Multiple layers are evaluated by matching a theoretical phase velocity spectrum to the measured spectrum. So far the method has been applied to the testing of pavements, but it may also be applicable in other fields such as ultrasonic testing of coated materials.

  6. The use of fluvial and marine sediments in the formulation of roller compacted concrete for use in pavements.

    PubMed

    Zdiri, M; Abriakb, N E; Ben Ouezdoua, M; Neji, J

    2009-07-01

    In the manufacture of Roller Compacted Concrete (RCC) used for pavement materials, various types of aggregates are used, such as crushed and rolled limestone or siliceous aggregates. The main objective is always to reach the maximum compactness to achieve higher mechanical performances. In the present work, fluvial and marine sediments, resulting from the dredging of harbours and rivers, were introduced as aggregates in the preparation of RCC for pavement construction, with a view to improving the mechanical strength of the RCC. This study included a granulometric, mineralogical and chemical characterization of the aggregates. The work also contains a mechanical characterization of the resulting material. The objective of the study was to find a resistant RCC, by developing materials such as sediments that are often classified as a waste and where their storage is harmful to the environment. The mechanical strengths obtained showed the profitability of using a Roller Compacted Concrete containing sediments. PMID:19705664

  7. Flexibility Program

    ERIC Educational Resources Information Center

    Connors, G. Patrick

    These brief guidelines for a muscular flexibility program state that the purpose of such a program is to increase the range of motion in order to avoid injuries and eliminate awkwardness in physical activities. A flexibility program is described as an extension of the warm-up period and should be an ongoing, permanent effort to lengthen muscles. A

  8. Flexible workover riser system

    SciTech Connect

    Hall, J.E.

    1981-08-04

    A method is described for performing operations in a well selected from a group or cluster of subsea wells which are produced through a production riser means to production facilities on a floating platform. There is provided a flexible workover riser on the platform which extends through a passage on the platform at a location remote from the moon pool for the production riser means. The flexible workover riser is run through said passage and guided into connection with the production tubing in the subsea well. Wireline or other well operations are then conducted through the connected flexible workover riser from the floating platform.

  9. High Performance Bottom-Gate-Type Amorphous InGaZnO Flexible Transparent Thin-Film Transistors Deposited on PET Substrates at Low Temperature

    NASA Astrophysics Data System (ADS)

    Lee, Hsin-Ying; Ye, Wan-Yi; Lin, Yung-Hao; Lou, Li-Ren; Lee, Ching-Ting

    2014-01-01

    The InGaZnO channel layer of bottom-gate-type flexible transparent thin-film transistors was deposited on polyethylene terephthalate substrates using a magnetron radio frequency cosputter system with a single InGaZnO target. The composition of the InGaZnO channel layer was controlled by sputtering at various Ar/O2 gas ratios. A 15-nm-thick SiO y insulator film was used to passivate the InGaZnO channel layer. Much better performances of the passivated devices were obtained, which verified the passivation function. To study the bending stability of the resulting flexible transparent thin-film transistors, a stress test with a bending radius of 1.17 cm for 1,500 s was carried out, which showed a variation in the effective filed-effect mobility and the threshold voltage of the unpassivated and passivated devices being maintained within 10 and 8%, respectively.

  10. Effect of whole body vibrations on performance indexes of aerobic power and flexibility in non-athlete men

    Microsoft Academic Search

    Babak Davoodi; Sajad Arshadi; Shirin Zilaei Bouri

    2010-01-01

    The aim of the present study was to investigate the effect of one session whole body vibration (WBV) on anaerobic power and flexibility in non-athletic male students. The participants were 12 untrained healthy male students (age: 25.42 years; body mass: 72.99 kg; height: 175.92 cm and body fat percentage: 19.69%). On the day of assessment, the subjects carried out 10

  11. Flexible responsive Janus nanosheets.

    PubMed

    Liu, Yijiang; Liang, Fuxin; Wang, Qian; Qu, Xiaozhong; Yang, Zhenzhong

    2015-02-12

    Flexible Janus nanosheets of molecular scale thickness (3.5 nm) are massively fabricated by a sol-gel process of a self-assembled monolayer of an amphiphilic silane onto a template. Groups of both sides are tuneable, and thus performance of the nanosheets, for example, is pH responsive. As a flexible solid emulsifier, the desired species can be wrapped with an individual nanosheet, which is pH triggered. PMID:25633051

  12. DEVELOPMENT OF A HYDROPHOBIC SUBSTANCE TO MITIGATE PAVEMENT ICE ADHESION

    EPA Science Inventory

    The specific problem to which this report is addressed is the development of a hydrophobic substance to mitigate the adhesion of ice to pavement as an alternative to deicing chemicals. The factors involved in evaluating this concept are the following: Economics; safety; environme...

  13. Nitrogen Transformations in Three Types of Permeable Pavement

    EPA Science Inventory

    In 2009, USEPA constructed a 0.4-ha (1-ac) parking lot at the Edison Environmental Center in Edison, NJ, that incorporated three different permeable pavement types - permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA). The driving lanes...

  14. Salt Frost Deterioration in Concrete Pavement --Causes and Mitigation

    E-print Network

    Salt Frost Deterioration in Concrete Pavement --Causes and Mitigation Zhichao Liu, Will Hansen and special effects such as surface tension and osmotic effect (salt solution). ·Below the nucleation the surface contains a salt solution, pore suction attracts surface liquid and additional ice growth may

  15. Regular Inspection and Maintenance Guidance for Porous Pavements

    E-print Network

    of factors including the occurrence of large storm events, seasonal changes, and traffic conditions. Signage should display limitation of design load (i.e. passenger vehicles only, light truck traffic, etc FOR INSPECTION OF POROUS PAVEMENTS Location: Inspector: Date: Time: Site Conditions: Date Since Last Rain Event

  16. Permeable Interlocking Concrete Pavement (PICP) for Stormwater Management

    E-print Network

    Permeable Interlocking Concrete Pavement (PICP) for Stormwater Management Benefits and Uses Traditional Concrete · Long-term Maintenance Required by Routine Vacuum Sweeping · Sweeping Cost May Be Off-set by Possible Reduction in Deicing Costs · Repairs Can be Made in Freezing Temperatures with Reinstated Concrete

  17. The Edison Environmental Center Permeable Pavement Site - slides

    EPA Science Inventory

    This is a presentation for a second Community Outreach Event called "Chemistry Works!" at West Windsor Public Library on Saturday, November 5th. It will review the permeable pavement research project at the Edison Environmental center. Besides slide persentation, two demo units w...

  18. Growth of Hierarchal Mesoporous NiO Nanosheets on Carbon Cloth as Binder-free Anodes for High-performance Flexible Lithium-ion Batteries

    PubMed Central

    Long, Hu; Shi, Tielin; Hu, Hao; Jiang, Shulan; Xi, Shuang; Tang, Zirong

    2014-01-01

    Mesoporous NiO nanosheets were directly grown on three-dimensional (3D) carbon cloth substrate, which can be used as binder-free anode for lithium-ion batteries (LIBs). These mesoporous nanosheets were interconnected with each other and forming a network with interval voids, which give rise to large surface area and efficient buffering of the volume change. The integrated hierarchical electrode maintains all the advantageous features of directly building two-dimensional (2D) nanostructues on 3D conductive substrate, such as short diffusion length, strain relaxation and fast electron transport. As the LIB anode, it presents a high reversible capacity of 892.6?mAh g?1 after 120 cycles at a current density of 100?mA g?1 and 758.1?mAh g?1 at a high charging rate of 700?mA g?1 after 150 cycles. As demonstrated in this work, the hierarchical NiO nanosheets/carbon cloth also shows high flexibility, which can be directly used as the anode to build flexible LIBs. The introduced facile and low-cost method to prepare NiO nanosheets on flexible and conductive carbon cloth substrate is promising for the fabrication of high performance energy storage devices, especially for next-generation wearable electronic devices. PMID:25491432

  19. Growth of Hierarchal Mesoporous NiO Nanosheets on Carbon Cloth as Binder-free Anodes for High-performance Flexible Lithium-ion Batteries

    NASA Astrophysics Data System (ADS)

    Long, Hu; Shi, Tielin; Hu, Hao; Jiang, Shulan; Xi, Shuang; Tang, Zirong

    2014-12-01

    Mesoporous NiO nanosheets were directly grown on three-dimensional (3D) carbon cloth substrate, which can be used as binder-free anode for lithium-ion batteries (LIBs). These mesoporous nanosheets were interconnected with each other and forming a network with interval voids, which give rise to large surface area and efficient buffering of the volume change. The integrated hierarchical electrode maintains all the advantageous features of directly building two-dimensional (2D) nanostructues on 3D conductive substrate, such as short diffusion length, strain relaxation and fast electron transport. As the LIB anode, it presents a high reversible capacity of 892.6 mAh g-1 after 120 cycles at a current density of 100 mA g-1 and 758.1 mAh g-1 at a high charging rate of 700 mA g-1 after 150 cycles. As demonstrated in this work, the hierarchical NiO nanosheets/carbon cloth also shows high flexibility, which can be directly used as the anode to build flexible LIBs. The introduced facile and low-cost method to prepare NiO nanosheets on flexible and conductive carbon cloth substrate is promising for the fabrication of high performance energy storage devices, especially for next-generation wearable electronic devices.

  20. Growth of hierarchal mesoporous NiO nanosheets on carbon cloth as binder-free anodes for high-performance flexible lithium-ion batteries.

    PubMed

    Long, Hu; Shi, Tielin; Hu, Hao; Jiang, Shulan; Xi, Shuang; Tang, Zirong

    2014-01-01

    Mesoporous NiO nanosheets were directly grown on three-dimensional (3D) carbon cloth substrate, which can be used as binder-free anode for lithium-ion batteries (LIBs). These mesoporous nanosheets were interconnected with each other and forming a network with interval voids, which give rise to large surface area and efficient buffering of the volume change. The integrated hierarchical electrode maintains all the advantageous features of directly building two-dimensional (2D) nanostructures on 3D conductive substrate, such as short diffusion length, strain relaxation and fast electron transport. As the LIB anode, it presents a high reversible capacity of 892.6 mAh g(-1) after 120 cycles at a current density of 100 mA g(-1) and 758.1 mAh g(-1) at a high charging rate of 700 mA g(-1) after 150 cycles. As demonstrated in this work, the hierarchical NiO nanosheets/carbon cloth also shows high flexibility, which can be directly used as the anode to build flexible LIBs. The introduced facile and low-cost method to prepare NiO nanosheets on flexible and conductive carbon cloth substrate is promising for the fabrication of high performance energy storage devices, especially for next-generation wearable electronic devices. PMID:25491432

  1. Filtration and clogging of permeable pavement loaded by urban drainage.

    PubMed

    Sansalone, J; Kuang, X; Ying, G; Ranieri, V

    2012-12-15

    Permeable pavement, as a sustainable infrastructure material can promote hydrologic restoration, particulate matter (PM) and solute control. However, filtration and commensurate clogging are two aspects of continued interest and discussion. This study quantifies filtration and clogging of cementitious permeable pavement (CPP) for loadings from 50 to 200 mg/L of hetero-disperse sandy-silt PM. The CPP mix design provides a hetero-disperse pore size distribution (PSD)(pore), effective porosity (?(e)) of 24% and median pore size of 658 ?m with a standard deviation of 457 ?m. The PM mass separation across the entire particle size distribution (PSD)(PM) exceeds 80%; with complete separation for PM greater than 300 ?m and 50% separation for suspended PM. Turbidity is reduced (42-95%), and effluent is below 10 NTU in the first quartile of a loading period. Permeable pavement illustrates reductions in initial (clean-bed) hydraulic conductivity (k(0)) with loading time. For all PM loadings, k(0) (3.1 10(-1) mm/s) was reduced to 10(-4) mm/s for runoff loading durations from 100 to 250 h, respectively. Temporal hydraulic conductivity (k) follows exponential profiles. Maintenance by vacuuming and sonication illustrate that 96-99% of k(0) is recovered. Permeable pavement constitutive properties integrated with measured PM loads and a year of continuous rainfall-runoff simulation illustrate k reduction with historical loadings. Study results measure and model filtration and hydraulic conductivity phenomena as well as maintenance requirements of permeable pavement directly loaded by urban drainage. PMID:22123518

  2. Analysis, testing and verification of the behavior of composite pavements under Florida conditions using a heavy vehicle simulator

    NASA Astrophysics Data System (ADS)

    Tapia Gutierrez, Patricio Enrique

    Whitetopping (WT) is a rehabilitation method to resurface deteriorated asphalt pavements. While some of these composite pavements have performed very well carrying heavy load, other have shown poor performance with early cracking. With the objective of analyzing the applicability of WT pavements under Florida conditions, a total of nine full-scale WT test sections were constructed and tested using a Heavy Vehicle Simulator (HVS) in the APT facility at the FDOT Material Research Park. The test sections were instrumented to monitor both strain and temperature. A 3-D finite element model was developed to analyze the WT test sections. The model was calibrated and verified using measured FWD deflections and HVS load-induced strains from the test sections. The model was then used to evaluate the potential performance of these test sections under critical temperature-load condition in Florida. Six of the WT pavement test sections had a bonded concrete-asphalt interface by milling, cleaning and spraying with water the asphalt surface. This method produced excellent bonding at the interface, with shear strength of 195 to 220 psi. Three of the test sections were intended to have an unbonded concrete-asphalt interface by applying a debonding agent in the asphalt surface. However, shear strengths between 119 and 135 psi and a careful analysis of the strain and the temperature data indicated a partial bond condition. The computer model was able to satisfactorily model the behavior of the composite pavement by mainly considering material properties from standard laboratory tests and calibrating the spring elements used to model the interface. Reasonable matches between the measured and the calculated strains were achieved when a temperature-dependent AC elastic modulus was included in the analytical model. The expected numbers of repetitions of the 24-kip single axle loads at critical thermal condition were computed for the nine test sections based on maximum tensile stresses and fatigue theory. The results showed that 4" slabs can be used for heavy loads only for low-volume traffic. To withstand the critical load without fear of fatigue failure, 6" slabs and 8" slabs would be needed for joint spacings of 4' and 6', respectively.

  3. Laboratory analysis of the infiltration capacity of interlocking concrete block pavements in car parks.

    PubMed

    Saudo-Fontaneda, Luis A; Rodriguez-Hernandez, Jorge; Vega-Zamanillo, Angel; Castro-Fresno, Daniel

    2013-01-01

    Interlocking concrete block pavements (ICBPs) have been widely used in car parks to reduce runoff. Researches have demonstrated that clogging is the most influential factor in the reduction of the infiltration capacity of this type of permeable pavement. Nevertheless, there is no laboratory study of the infiltration performance of ICBPs that combines clogging levels with variables related with the topography of car parks such as runoff surface length (R(SL)) and surface slope (S(S)). This paper studies the infiltration behaviour of ICBP during their operational life in a car park using an improved version of the Cantabrian Fixed (CF) Infiltrometer. This laboratory device simulates direct rainfall and runoff from adjacent impervious areas over an ICBPs surface of 0.25 m(2) for different slopes (0, 3, 5, 7 and 10%) and three scenarios of clogging (surface newly built, surface clogged and surface clogged with maintenance). This paper presents the results of the tests and a statistical analysis based on three regression models (corresponding to each clogging scenario) depending on the R(SL) and S(S) variables. All models passed a confidence level of 95%, presenting high R(2) values and showing that R(SL) is a more influential variable than the S(S) for all clogging scenarios. PMID:23202575

  4. Solution-processed high-performance flexible 9, 10-bis(phenylethynyl)anthracene organic single-crystal transistor and ring oscillator

    NASA Astrophysics Data System (ADS)

    Cai, Xiaozhou; Ji, Deyang; Jiang, Lang; Zhao, Guangyao; Tan, Jiahui; Tian, Guofeng; Li, Jingze; Hu, Wenping

    2014-02-01

    Organic semiconductor of 9, 10-bis(phenylethynyl)anthracene (BPEA) single crystal ribbon with ultra-long length has been prepared by solution drop casting method, where the growth direction was controlled with the seed crystal. The BPEA single crystal ribbon based field-effect transistors show high hole mobility up to 3.2 cm2/V.s, and the inverters exhibited the highest gain of 92. The complex device such as 5-stage ring oscillator consisting of 10 transistors was also constructed on a single crystal ribbon. This straightforward methodology was applied to fabricate plastic transistors on the flexible substrate, showing high performance even after repeatedly bending of 300 times.

  5. High performance flexible top-emitting warm-white organic light-emitting devices and chromaticity shift mechanism

    SciTech Connect

    Shi, Hongying; Deng, Lingling; Chen, Shufen, E-mail: iamsfchen@njupt.edu.cn, E-mail: wei-huang@njupt.edu.cn; Xu, Ying; Zhao, Xiaofei; Cheng, Fan [Key Laboratory for Organic Electronics and Information Displays (KLOEID) and Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 210023 Nanjing (China)] [Key Laboratory for Organic Electronics and Information Displays (KLOEID) and Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 210023 Nanjing (China); Huang, Wei, E-mail: iamsfchen@njupt.edu.cn, E-mail: wei-huang@njupt.edu.cn [Key Laboratory for Organic Electronics and Information Displays (KLOEID) and Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 210023 Nanjing (China) [Key Laboratory for Organic Electronics and Information Displays (KLOEID) and Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 210023 Nanjing (China); Jiangsu-Singapore Joint Research Center for Organic/Bio- Electronics and Information Displays and Institute of Advanced Materials, Nanjing University of Technology, Nanjing 211816 (China)

    2014-04-15

    Flexible warm-white top-emitting organic light-emitting devices (TEOLEDs) are fabricated onto PET substrates with a simple semi-transparent cathode Sm/Ag and two-color phosphors respectively doped into a single host material TCTA. By adjusting the relative position of the orange-red EML sandwiched between the blue emitting layers, the optimized device exhibits the highest power/current efficiency of 8.07 lm/W and near 13 cd/A, with a correlated color temperature (CCT) of 4105 K and a color rendering index (CRI) of 70. In addition, a moderate chromaticity variation of (-0.025, +0.008) around warm white illumination coordinates (0.45, 0.44) is obtained over a large luminance range of 1000 to 10000 cd/m{sup 2}. The emission mechanism is discussed via delta-doping method and single-carrier device, which is summarized that the carrier trapping, the exciton quenching, the mobility change and the recombination zone alteration are negative to color stability while the energy transfer process and the blue/red/blue sandwiched structure are contributed to the color stability in our flexible white TEOLEDs.

  6. Deconstructing a Plant Macromolecular Assembly: Chemical Architecture, Molecular Flexibility, And Mechanical Performance of Natural and Engineered Potato Suberins

    PubMed Central

    2015-01-01

    Periderms present in plant barks are essential protective barriers to water diffusion, mechanical breakdown, and pathogenic invasion. They consist of densely packed layers of dead cells with cell walls that are embedded with suberin. Understanding the interplay of molecular structure, dynamics, and biomechanics in these cell wall-associated insoluble amorphous polymeric assemblies presents substantial investigative challenges. We report solid-state NMR coordinated with FT-IR and tensile strength measurements for periderms from native and wound-healing potatoes and from potatoes with genetically modified suberins. The analyses include the intact suberin aromaticaliphatic polymer and cell-wall polysaccharides, previously reported soluble depolymerized transmethylation products, and undegraded residues including suberan. Wound-healing suberized potato cell walls, which are 2 orders of magnitude more permeable to water than native periderms, display a strikingly enhanced hydrophilichydrophobic balance, a degradation-resistant aromatic domain, and flexibility suggestive of an altered supramolecular organization in the periderm. Suppression of ferulate ester formation in suberin and associated wax remodels the periderm with more flexible aliphatic chains and abundant aromatic constituents that can resist transesterification, attenuates cooperative hydroxyfatty acid motions, and produces a mechanically compromised and highly water-permeable periderm. PMID:24502663

  7. Acute Effects of Two Different Warm-Up Protocols on Flexibility and Lower Limb Explosive Performance in Male and Female High Level Athletes

    PubMed Central

    Tsolakis, Charilaos; Bogdanis, Gregory C.

    2012-01-01

    This study examined the effects of two different warm-up protocols on lower limb power and flexibility in high level athletes. Twenty international level fencers (10 males and 10 females) performed two warm-up protocols that included 5-min light jogging and either short (15s) or long (45s) static stretching exercises for each of the main leg muscle groups (quadriceps, hamstrings and triceps surae), followed by either 3 sets of 3 (short stretching treatment), or 3 sets of 5 tuck jumps (long stretching treatment), in a randomized crossover design with one week between treatments. Hip joint flexion was measured with a Lafayette goniometer before and after the 5-min warm-up, after stretching and 8 min after the tuck jumps, while counter movement jump (CMJ) performance was evaluated by an Ergojump contact platform, before and after the stretching treatment, as well as immediately after and 8 minutes after the tuck jumps. Three way ANOVA (condition, time, gender) revealed significant time (p < 0.001) and gender (p < 0.001) main effects for hip joint flexion, with no interaction between factors. Flexibility increased by 6. 8 1.1% (p < 0.01) after warm-up and by another 5.8 1.6% (p < 0.01) after stretching, while it remained increased 8 min after the tuck jumps. Women had greater ROM compared with men at all time points (125 8 vs. 94 4 p<0.01 at baseline), but the pattern of change in hip flexibility was not different between genders. CMJ performance was greater in men compared with women at all time points (38.2 1.9 cm vs. 29.8 1.2 cm p < 0.01 at baseline), but the percentage of change CMJ performance was not different between genders. CMJ performance remained unchanged throughout the short stretching protocol, while it decreased by 5.5 0.9% (p < 0.01) after stretching in the long stretching protocol However, 8 min after the tuck jumps, CMJ performance was not different from the baseline value (p = 0.075). In conclusion, lower limb power may be decreased after long periods of stretching, but performance of explosive exercises may reverse this phenomenon. Key points Stretching of the main leg muscle groups for 45 s results in a relatively large decrease (by 5.5%) in subsequent jumping performance Stretching of the main leg muscle groups for only 15 s results in an increase in flexibility similar to that of the longer duration stretching (by 12.6%), with no change in subsequent jumping performance Performance of a PAP exercise such as tuck jumps may reverse the negative effects of long duration stretching on leg muscle power. However, jumping performance is not increased above baseline Speed/power athletes should be advised against using long duration stretching. The number of repetitions of a PAP exercise such as the tuck jumps, should be further examined in order to induce an increase in explosive performance during competition PMID:24150077

  8. Research on the characteristics of temperature field of asphalt pavement in seasonal frozen region

    NASA Astrophysics Data System (ADS)

    Qiao, Jiangang; Liu, Weizheng

    2014-08-01

    The characteristics of climate in seasonal frozen area are low temperature and a large range of temperature variation between day and night in winter. These characteristics often lead to problems of asphalt pavement, especially transverse cracks. To reduce the problems of asphalt pavement, it is necessary to examine the distribution of the temperature range of asphalt pavement. A three-dimensional finite element model was used, taking the SMA asphalt pavement as an example with solid70 and plane55 unit features of ANSYS software. It can obtain the relationship between temperature gradient and time and the relationship between temperature gradient and depth. In addition, a function relation model of stress and time was also established. It can provide a theoretical basis for the prevention and treatment of problems of asphalt pavement in seasonal frozen area. Moreover, it has an important significance for improving asphalt pavement design.

  9. Experimental studies of the dilution of vehicle exhaust pollutants by environment-protecting pervious pavement.

    PubMed

    Liu, Chung-Ming; Chen, Jui-Wen; Tsai, Jen-Hui; Lin, Wei-Shian; Yen, M-T; Chen, Ting-Hao

    2012-01-01

    This study determines whether environment-protecting pervious pavement can dilute pollutants immediately after emissions from vehicle. The turbulence-driven dry-deposition process is too slow to be considered in this aspect. The pavement used is the JW pavement (according to its inventors name), a high-load-bearing water-permeable pavement with patents in over 100 countries, which has already been used for more than 8 years in Taiwan and is well suited to replacing conventional road pavement, making the potential implementation of the study results feasible. The design of this study included two sets of experiments. Variation of the air pollutant concentrations within a fenced area over the JW pavement with one vehicle discharging emissions into was monitored and compared with results over a non-JW pavement. The ambient wind speed was low during the first experiment, and the results obtained were highly credible. It was found that the JW pavement diluted vehicle pollutant emissions near the ground surface by 40%-87% within 5 min of emission; whereas the data at 2 m height suggested that about 58%-97% of pollutants were trapped underneath the pavement 20 min after emission. Those quantitative estimations may be off by +/- 10%, if errors in emissions and measurements were considered. SO2 and CO2 underwent the most significant reduction. Very likely, pollutants were forced to move underneath due to the special design of the pavement. During the second experiment, ambient wind speeds were high and the results obtained had less credibility, but they did not disprove the pollutant dilution capacity of the JW pavement. In order to track the fate of pollutants, parts of the pavement were removed to reveal a micro version of wetland underneath, which could possibly hold the responsibility of absorbing and decomposing pollutants to forms harmless to the environment and human health. PMID:22393814

  10. Piping Flexibility

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A NASA computer program aids Hudson Engineering Corporation, Houston, Texas, in the design and construction of huge petrochemical processing plants like the one shown, which is located at Ju'aymah, Saudi Arabia. The pipes handling the flow of chemicals are subject to a variety of stresses, such as weight and variations in pressure and temperature. Hudson Engineering uses a COSMIC piping flexibility analysis computer program to analyze stresses and unsure the necessary strength and flexibility of the pipes. This program helps the company realize substantial savings in reduced engineering time.

  11. A road pavement full-scale test track containing stabilized bottom ashes.

    PubMed

    Toraldo, E; Saponaro, S

    2015-05-01

    This paper reports the results of a road pavement full-scale test track built by using stabilized bottom ash (SBA) from an Italian municipal solid waste incinerator as the aggregate in granular foundation, cement-bound mixes and asphalt concretes. The investigation focused on both the performance and the environmental compatibility of such mixes, especially with regard to the effects of mixing, laying and compaction. From the road construction point of view, the performance related to the effects of mixing, laying and compaction on constructability was assessed, as well as the volumetric and the mechanical properties. Environmental aspects were investigated by leaching tests. The results suggested that SBA meets the environmental Italian law for the reuse of non-hazardous waste and could be used as road material with the procedures, plants and equipment currently used for road construction. PMID:25354811

  12. The effects of buffer layers on the performance and stability of flexible InGaZnO thin film transistors on polyimide substrates

    SciTech Connect

    Ok, Kyung-Chul; Park, Jin-Seong, E-mail: hkim-2@naver.com, E-mail: jsparklime@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Ko Park, Sang-Hee; Kim, H., E-mail: hkim-2@naver.com, E-mail: jsparklime@hanyang.ac.kr [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Hwang, Chi-Sun [Transparent Electronics Team, ETRI, Daejeon 305-350 (Korea, Republic of); Soo Shin, Hyun; Bae, Jonguk [LG Display R and D Center, LG Display Co., Ltd., Paju 413-811 (Korea, Republic of)

    2014-02-10

    We demonstrated the fabrication of flexible amorphous indium gallium zinc oxide thin-film transistors (TFTs) on high-temperature polyimide (PI) substrates, which were debonded from the carrier glass after TFT fabrication. The application of appropriate buffer layers on the PI substrates affected the TFT performance and stability. The adoption of the SiN{sub x}/AlO{sub x} buffer layers as water and hydrogen diffusion barriers significantly improved the device performance and stability against the thermal annealing and negative bias stress, compared to single SiN{sub x} or SiO{sub x} buffer layers. The substrates could be bent down to a radius of curvature of 15?mm and the devices remained normally functional.

  13. Design Methodologies of Asphalt Pavement Used in China and Mozambique

    NASA Astrophysics Data System (ADS)

    Francisco Rufino Diogo, Jose; Shubber, Ammar Abbas Mohammed; Lin, Mu Han

    This study discusses and compares Asphalt Concrete (AC) pavement design methodologies used in China and Mozambique (based on South African Transportation and Communication Commission (SATCC) methodologies). The SATCC design methodologies use California Bearing Ratio (CBR) and catalogues methods. The South African catalogues are basically used for roads with traffic less than 30 million ESAs. The design catalogues method give small thickness than CBR and Chinese methods. The Chinese and the South African design methods give nearly the same thickness; this study concludes that these methods can be used in both countries; China and Mozambique. The results also show that the strong point of Chinese method is verifying the tensile stress and allowable displacement on the pavement calculated from computer program APDS.

  14. TRUCK PERFORMANCE CURVES REFLECTIVE OF TRUCK AND PAVEMENT CHARACTERISTICS

    E-print Network

    Rakha, Hesham A.

    ABSTRACT The paper utilizes a linearly increasing variable power vehicle dynamics model to develop modeling, vehicle dynamics, roadway design, truck climbing lanes. INTRODUCTION Mannering and Kilareski

  15. BEHAVIOR AND PERFORMANCE OF UTW ON THIN ASPHALT PAVEMENT

    Microsoft Academic Search

    Jos Balbo; Deividi Pereira; Andra Severi

    During the 1999 spring, two sections of ultra-thin whitetopping (UTW) were built in an urban street in So Paulo City over a thin 45 mm asphalt layer. The UTW was constructed at a bus stop within the University campus, defining two panels of squared 0.6 and 1.0 m and 95 mm slabs. A high strength concrete was applied and the

  16. Contributions to an Improved Oxygen and Thermal Transport Model and Development of Fatigue Analysis Software for Asphalt Pavements

    E-print Network

    Jin, Xin

    2012-02-14

    Fatigue cracking is one primary distress in asphalt pavements, dominant especially in later years of service. Prediction of mixture fatigue resistance is critical for various applications, e.g., pavement design and preventative maintenance. The goal...

  17. Leaching of organic contaminants from storage of reclaimed asphalt pavement

    Microsoft Academic Search

    Malin Norin

    2004-01-01

    Recycling of asphalt has been promoted by rapid increases in both the use and price of petroleum?based bitumen. Semi?volatile organic compounds in leachates from reclaimed asphalt pavement, measured in field samples and in laboratory column test, were analysed through a GC\\/MS screen?test methodology. Sixteen PAH (polyaromatic hydrocarbons) were also analysed in leachates from the column study. The highest concentrations of

  18. Mechanistic modeling of roughness on continuously reinforced concrete pavement

    E-print Network

    Sriraman, Supriya

    1996-01-01

    ABSTRACT Mechanistic Modeling of Roughness on Continuously Reinforced Concrete Pavements. (December 1996) Supriya Sriraman, B. S. , Osmania University, India Chair of Advisory Committee: Dr. Dan G. Zollinger Roughness can be termed as the irregularity... conunittee, Dr. Dan Zollinger, for the support and guidance he extended to me. During the two years I worked with him, he has always been there to advice me on my research and help me with problems that I could not tackle myself. I am immensely thankful...

  19. Effects of Various Deicing Chemicals on Pavement Concrete Deterioration

    Microsoft Academic Search

    HYOMIN LEE; ROBERT D. CODY; ANITA M. CODY; PAUL G. SPRY

    The deleterious effects of deicers on concrete pavements and bridges have concerned concrete researchers for several decades. The present study experimentally investigates the effects of different deicers on concrete deterioration. Laboratory simulations of environmental conditions (wet\\/dry and freeze\\/thaw cycling) were conducted on highway concrete samples with various deicer chemicals (NaCl, CaCl 2, MgCl2, calcium magnesium acetate (CMA) of 5 different

  20. Abrasion resistance of concrete containing nano-particles for pavement

    Microsoft Academic Search

    Hui Li; Mao-hua Zhang; Jin-ping Ou

    2006-01-01

    The abrasion resistance of concrete containing nano-particles for pavement is experimentally studied. Both nano-TiO2 and nano-SiO2 are, respectively, employed to be as the additives. For comparison, the abrasion resistance of plain concrete and the concrete containing polypropylene (PP) fibers is also experimentally studied in this work. The test results indicate that the abrasion resistance of concretes containing nano-particles and PP

  1. Evolving flexible joint morphologies

    Microsoft Academic Search

    Jared M. Moore; Philip K. McKinley

    2012-01-01

    Transferring virtual robotic designs into physical robots has become possible with the development of 3D printers. Accurately simulating the performance of real robots in a virtual environment requires modeling a variety of conditions, including the physical composition of the robots themselves. In this paper, we investigate how modeling material flexibility through the use of a passive joint affects the resulting

  2. Human resource bundles and manufacturing performance: Organizational logic and flexible production systems in the world auto industry

    Microsoft Academic Search

    John MacDuffie

    1995-01-01

    Using a unique international data set from a 1989-90 survey of 62 automotive assembly plants, the author tests two hypotheses: that innovative HR practices affect performance not individually but as interrelated elements in an internally consistent HR \\

  3. Using ground-penetrating radar for assessing the structural needs of asphalt pavements

    Microsoft Academic Search

    C. Plati; A. Loizos

    2012-01-01

    Ground-penetrating radar (GPR) is a nondestructive testing (NDT) approach for pavement investigation that has been developed and improved upon over the past 30 years. This paper aimed to document how the GPR technique could be incorporated successfully into the process of assessing the structural needs of asphalt pavements. Background information is provided regarding the usage of GPR for the evaluation

  4. Nondestructive testing of asphalt pavements for structural condition evaluation: a state of the art

    Microsoft Academic Search

    Amit Goel; Animesh Das

    2008-01-01

    Nondestructive testing provides ideal means to test pavement structure in a rapid and convenient manner. In last few years, significant development has taken place in this field. This paper, presents some of the major conventional as well as emerging nondestructive evaluation methods for in situ structural assessment of asphalt pavements. Discussion of methods is primarily directed towards the estimation of

  5. Blind deconvolution via independent component analysis for thin-pavement thickness estimation using GPR

    Microsoft Academic Search

    Khaled CHAHINE; Vincent BALTAZART; Xavier Drobert; Yide WANG

    2009-01-01

    Blind deconvolution of sparse spikes is a well-known problem in the fields of seismic exploration and ultrasonic nondestructive testing. In measuring thin layer thickness of asphalt pavements using GPR, a similar problem arises; the sparse reflectivity series representing the layered structure of the pavement convolved with the radar wavelet results in masking closely spaced reflections. A successful deconvolution retrieves the

  6. Multitarget detection\\/tracking for monostatic ground penetrating radar: application to pavement profiling

    Microsoft Academic Search

    Umberto Spagnolini; Vittorio Rampa

    1999-01-01

    Monostatic ground penetrating radar (GPR) has proven to be a useful technique in pavement profiling. In road and highway pavements, layer thickness and permittivity of asphalt and concrete can be estimated by using an inverse scattering approach. Layer-stripping inversion refers to the iterative estimation of layer properties from amplitude and time of delay (TOD) of echoes after their detection. This

  7. A new NDT tool for pavement evaluation: Step-Frequency GPR

    E-print Network

    A new NDT tool for pavement evaluation: Step-Frequency GPR H. Thomas Yu Office of Asset Management, Pavement, and Construction Federal Highway Administration #12;Ground Penetrating Radar #12;The APE #12;SF-GPR mix · Material degradation Moisture detection Cover depth detection #12;GPR testing #12;Impulse vs

  8. Dynamical Processes on Desert Pavements and the Healing of Surficial Disturbances

    E-print Network

    Ahmad, Sajjad

    of a layer of accumulating aeolian sediment. The results presented here support a recent model of pavement formation on volcanic flow surfaces that emphasizes the importance of dust-accretion over deflation in pavement genesis (Wells et al., 1985; Mc- Fadden et al., 1987). SETTING AND EXPERIMENTAL APPROACH

  9. EVALUATION OF THE INFLUENCE OF TACK COAT CONSTRUCTION FACTORS ON THE BOND STRENGTH BETWEEN PAVEMENT LAYERS

    E-print Network

    Administration. 16. ABSTRACT This study investigated the influence of several factors on the adhesive bondEVALUATION OF THE INFLUENCE OF TACK COAT CONSTRUCTION FACTORS ON THE BOND STRENGTH BETWEEN PAVEMENT Evaluation of the Influence of Tack Coat Construction Factors on the Bond Strength between Pavement Layers 7

  10. Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site - Abstract

    EPA Science Inventory

    The EPA?s Urban Watershed Management Branch (UWMB) is monitoring an instrumented, working, 110-space pervious pavement parking at EPA?s Edison Environmental Center (EEC). Permeable pavement systems are classified as stormwater best management practices (BMPs) which reduce runo...

  11. Desert pavement development and landscape stability on the Eastern Libyan Plateau, Egypt

    NASA Astrophysics Data System (ADS)

    Adelsberger, Katherine A.; Smith, Jennifer R.

    2009-06-01

    Desert pavement surfaces of the eastern Libyan Plateau in central Egypt represent a stable landscape preserving Middle and Upper Paleolithic artifacts. Detailed measurements of pavement clasts indicate significant variability in clast size, density, lithology and orientation between pavements, but no spatial relationship among any of these pavement variables over the study area. Pavement characteristics are unrelated to local geomorphic features including slope gradient and aspect, suggesting a desert pavement surface that has developed without significant influence from transporting mechanisms such as overland flow and slope failure. Meridional vertical cracks in surface clasts implicate thermal stresses due to diurnal solar variation as a mechanical weathering process, whereas the presence of a clast-free silty layer within all soil profiles indicates that these are accretionary pavement surfaces that have grown upward over time. The desert pavement in this region has likely developed in situ through mechanical breakdown of surface clasts and desert pedogenesis, indicating long-term stability for this region and minimal taphonomic effects on artifacts > 2 cm in diameter deposited on this surface over the last ca. 100 ka.

  12. Application of a New Decision Method in Expressway Pavement Management System

    Microsoft Academic Search

    Jiang-hong Zeng; Jia Xu

    2009-01-01

    We have proposed the decision-making model of maintenance for cement concrete pavement, by analyzing the formation and evolution characteristics of cement concrete pavement diseases and considering the actual maintenance of Hunan Province, under the thought of preventive maintenance, According to the requirement of preventive maintenance, during the schedule making, we should firstly choose the preventive maintenance measures, such as replace

  13. TOLLWAY LCCA PROCESS FOR ADDAMS MEMORIAL TOLLWAY ADDAMS EXPRESSWAY PAVEMENT RECONSTRUCTION --

    E-print Network

    TOLLWAY LCCA PROCESS FOR ADDAMS MEMORIAL TOLLWAY Page 1 ADDAMS EXPRESSWAY PAVEMENT RECONSTRUCTION and for the maintenance activities anticipated over a 50-year life span for each of the pavement types under consideration and expand capacity along the Jane Addams Memorial Tollway between I-39 and the Kennedy Expressway

  14. A new technology of preventive reinforcement for the semi-rigid base of asphalt pavement expressway

    Microsoft Academic Search

    Guo-xiang Hu; Jie Li; Bai-lin Sun

    2011-01-01

    As for the existing treated methods for the base layer of asphalt pavement, there were at least two main shortages: the one was the lagged technology, the other one was the unseasonable choosing of treated time. In order to develop a new preventive maintenance technologies for the asphalt pavement, in this paper, the authors propose that, before the damages happen

  15. Permeable pavement monitoring at the EPA's Edison Environmental Center demonstration site

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used pervious pavement systems. Practitioners need additional studies of pervious pavement systems in its intended application (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions...

  16. Development of methodology for detection of defect locations in pavement profile

    E-print Network

    Rawool, Shubham Shivaji

    2005-08-29

    in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content by: Dan Zollinger Dallas Little (Chair of Committee... iii ABSTRACT Development of Methodology for Detection of Defect Locations in Pavement Profile. (May 2004) Shubham Rawool, B.E., Goa University Chair of Advisory Committee: Dr. Dan Zollinger Pavement smoothness has become a standard measure...

  17. FRP Dowels for Concrete Pavements Darren Eddie, Junior Structural Engineer, Reid Crowther & Partners;

    E-print Network

    = L FRP Dowels for Concrete Pavements By Darren Eddie, Junior Structural Engineer, Reid Crowther - Introduction Joints are used in concrete pavements in order to control cracking due to thermal of steel dowels due to the application of de-icing salts causes severe deterioration of concrete highway

  18. The Edison Environmental Center Permeable Pavement Site: Initial Results from a Stormwater Control Designed for Monitoring

    EPA Science Inventory

    There are few detailed studies of full-scale, replicated, actively-used permeable pavement systems. Practitioners need additional studies of permeable pavement systems in its intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage conditio...

  19. Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site - presentation

    EPA Science Inventory

    The EPA?s Urban Watershed Management Branch has been monitoring an instrumented 110-space pervious pavement parking lot. The lot is used by EPA personnel and visitors to the Edison Environmental Center. The design includes 28-space rows of three permeable pavement types: asphal...

  20. Flexible ultrasonic transducers.

    PubMed

    Kobayashi, Makiko; Jen, Cheng-Kuei; Lvesque, Daniel

    2006-08-01

    Flexible ultrasonic transducers (UTs) consisting of a metal foil, a piezoelectric ceramic film, and a top electrode have been developed. The flexibility is realized owing to the porosity of piezoelectric film and the thinness of metal foil. In this paper, the stainless steel (SS), lead-zirconate-titanate (PZT)/PZT composite and silver paste were chosen as metal foil, piezoelectric film, and top electrode materials, respectively. The SS foil serves as both substrate and bottom electrode. The PZT/PZT piezoelectric composite film is made by the sol-gel spray technique. PZT/PZT films of thicknesses from 40 to 70 microm were fabricated onto SS foils. The capability of these flexible sensors operated in the pulse-echo mode for nondestructive testing on flat and curved surfaces of different materials at room temperature and 160 degrees C has been demonstrated. Numerical simulations of the effects of the metal foil thickness on the ultrasonic performance of flexible UTs also were carried out, and the results are in reasonable agreement with experimental data. In addition, a PZT/PZT flexible transducer showed a signal strength comparable with that obtained by a commercial room temperature broad bandwidth transducer. PMID:16921900

  1. Self Consistent Simulation of C-V Characterization and Ballistic Performance of Double Gate SOI Flexible-FET Incorporating QM Effects

    E-print Network

    Zubair Al Azim; Nadim Chowdhury; Iftikhar Ahmad Niaz; Md. Hasibul Alam; Imtiaz Ahmed; Quazi D. M. Khosru

    2012-11-16

    Capacitance-Voltage (C-V) & Ballistic Current- Voltage (I-V) characteristics of Double Gate (DG) Silicon-on- Insulator (SOI) Flexible FETs having sub 35nm dimensions are obtained by self-consistent method using coupled Schrodinger- Poisson solver taking into account the quantum mechanical effects. Although, ATLAS simulations to determine current and other short channel effects in this device have been demonstrated in recent literature, C-V & Ballistic I-V characterizations by using self-consistent method are yet to be reported. C-V characteristic of this device is investigated here with the variation of bottom gate voltage. The depletion to accumulation transition point (i.e. Threshold voltage) of the C-V curve should shift in the positive direction when the bottom gate is negatively biased and our simulation results validate this phenomenon. Ballistic performance of this device has also been studied with the variation of top gate voltage.

  2. Compensation Opportunities and Application Procedures Simplified There is no entitlement to any Flexible Pay Option. In order to be eligible, an employee must have an accurate Role Description, current Performance Evaluation, and successful

    E-print Network

    Lawrence, Rick L.

    Performance Evaluation, and successful completion of their probationary period. The employee must have Flexible Pay Option. In order to be eligible, an employee must have an accurate Role Description, current recent performance review. Lump Sum Bonus In-range Progression Progression Pay Strategic Pay Definition

  3. Contemporary biogenic formation of clay pavements by eucalypts: further support for the phytotarium concept

    PubMed Central

    Pate, John S.; Verboom, William H.

    2009-01-01

    Background and Aims Clayey (sodosolic) pavements were studied in lateral root catchments of eucalypts where mixed myrtaceous:proteaceous vegetation was colonizing a dune of quartzitic sand blown out from a playa lake during late Pleistocene times. The site at Chillinup in south-west Western Australia provided an opportunity to examine these signature pavements in an unequivocally recent setting, and to assess their effects on competing non-eucalypt vegetation. Methods Pavements were located, and their extents and depths assessed by probing with steel rods, followed by corings and pit excavations using an air spade. Listings of plant species, growth forms and root morphologies were assembled for different vegetation zones in a representative transect across the dune. A deep cutting through the dune provided details on pavement morphology and modifications to the sand deposit bioengineered by eucalypt and heath vegetation. Key Results Clay pavements comprised closely spaced, round-topped columns whose mean diameters and depths varied between eucalypt species. Incipient pavement formation was characterized by clumps of clay deposited around fine root material. Pavements appeared to have been synthesized in situ from locally accessed and imported constituents. Understoreys on superficial pavements of a tree eucalypt were considerably less dense and biodiverse than on the deeper pavements of two mallee species, whilst most profuse vegetation cover was encountered in heath on unmodified (non-pavemented) sand. Certain species were restricted to superficially located pavements, whilst other generalist species occurred widely across the dune. Relict pavements formed by earlier generations of eucalypts were present in certain areas of the transect and in soil profiles of the cutting. Some relict pavements colonized by proteaceous shrubs were overprinted with ferricrete. Conclusions Clay pavements formed by eucalypts have pronounced effects on understorey vegetation and may have been instrumental in establishment of the complex mosaics of mallee-woodland and proteaceous heathland observed across semi-arid landscapes of south-west Western Australia. Findings are related to earlier observations on the range of plant-mediated changes in soil profiles discussed in the recently advanced Phytotarium concept. PMID:19141601

  4. Performance of an aircraft tire under cyclic braking and of a currently operational antiskid braking system

    NASA Technical Reports Server (NTRS)

    Tanner, J. A.

    1972-01-01

    An experimental investigation was conducted to study the performance of an aircraft tire under cyclic braking conditions and to study the performance of a currently operational aircraft antiskid braking system. Dry, damp, and flooded runway surface conditions were used in the investigation. The results indicated that under cyclic braking conditions the braking and cornering-force friction coefficients may be influenced by fluctuations in the vertical load, flexibility in the wheel support, and the spring coupling between the wheel and the tire-pavement interface. The cornering capability was shown to be negligible at wheel slip ratios well below a locked-wheel skid under all test surface conditions. The maximum available brake-force friction coefficient was shown to be dependent upon the runway surface condition, upon velocity, and, for wet runways, upon tire differences. Moderate reductions in vertical load and brake system pressure did not significantly affect the overall wet-runway performance of the tire.

  5. Strain gage installation and survivability on geosynthetics used in flexible pavements

    Microsoft Academic Search

    Jeremy A. Brooks

    2009-01-01

    The use of foil type strain gages on geosynthetics is poorly documented. In addition, very few individuals are versed in proper installation techniques or calibration methods. Due to the limited number of knowledgeable technicians there is no information regarding the susceptibility of theses gages to errors in installation by inexperienced installers. Also lacking in the documentation related to the use

  6. Strain gage installation and survivability on geosynthetics used in flexible pavements

    NASA Astrophysics Data System (ADS)

    Brooks, Jeremy A.

    The use of foil type strain gages on geosynthetics is poorly documented. In addition, very few individuals are versed in proper installation techniques or calibration methods. Due to the limited number of knowledgeable technicians there is no information regarding the susceptibility of theses gages to errors in installation by inexperienced installers. Also lacking in the documentation related to the use of foil type strain gages on geosynthetics is the survivability of the gages in field conditions. This research documented procedures for installation, calibration, and survivability used by the project team to instruments a full scale field installation in Marked Tree, AR. This research also addressed sensitivity to installation errors on both geotextile and geogrid. To document the process of gage installation an experienced technician, Mr. Joe Ables, formerly of the UASCE Waterways Experiment Station, was consulted. His techniques were combined with those discovered in related literature and those developed by the research team to develop processes that were adaptable to multiple gage geometries and parent geosynthetics. These processes were described and documented in a step by step manner with accompanying photographs, which should allow virtually anyone with basic electronics knowledge to install these gages properly. Calibration of the various geosynthetic / strain gage combinations was completed using wide width tensile testing on multiple samples of each material. The tensile testing process was documented and analyzed using digital photography to analyze strain on the strain gage itself. Calibration factors for each geosynthtics used in the full scale field testing were developed. In addition, the process was thoroughly documented to allow future researchers to calibrate additional strain gage and geosynthetic combinations. The sensitivity of the strain gages to installation errors was analyzed using wide width tensile testing and digital photography to determine the variability of the data collected from gages with noticeable installation errors as compared to properly installed gages. Induced errors varied based on the parent geosynthetics material, but included excessive and minimal waterproofing, gage rotation, gage shift, excessive and minimal adhesive, and excessive and minimal adhesive impregnation loads. The results of this work indicated that minor errors in geotextile gage installation that are noticeable and preventable by the experienced installer have no statistical significance on the data recorded during the life span of geotextile gages; however the lifespan of the gage may be noticeably shortened by such errors. Geogrid gage installation errors were found to cause statistically significant changes in the data recorded from improper installations. The issue of gage survivability was analyzed using small scale test sections instrumented and loaded similarly to field conditions anticipated during traditional roadway construction. Five methods of protection were tested for both geotextile and geogrid including a sand blanket, inversion, semi-hemispherical PCV sections, neoprene mats, and geosynthetic wick drain. Based on this testing neoprene mats were selected to protect geotextile installed gages, and wick drains were selected to protect geogrid installed gages. These methods resulted in survivability rates of 73% and 100% in the full scale installation respectively. This research and documentation may be used to train technicians to install and calibrate geosynthetic mounted foil type strain gages. In addition, technicians should be able to install gages in the field with a high probability of gage survivability using the protection methods recommended.

  7. Flexible protection for metal bellows

    NASA Technical Reports Server (NTRS)

    Kimble, K. G.

    1970-01-01

    RTV silicone is used with a braided wire sheath surrounding the metal bellows in fluid transfer systems. It demonstrated best overall performance in flexibility and shock absorbing tests, high temperature, low temperature, and salt spray.

  8. Individual inconsistencies in basal and summit metabolic rate highlight flexibility of metabolic performance in a wintering passerine.

    PubMed

    Corts, Pablo Andrs; Petit, Magali; Lewden, Agns; Milbergue, Myriam; Vzina, Franois

    2015-03-01

    Resident passerines inhabiting high latitude environments are faced with strong seasonal changes in thermal conditions and energy availability. Summit metabolic rate (maximal metabolic rate elicited by shivering during cold exposure: Msum ) and basal metabolic rate (BMR) vary in parallel among seasons and increase in winter due to cold acclimatization, and these adjustments are thought to be critical for survival. Wintering individuals expressing consistently higher Msum and BMR could therefore be seen as better performers with higher chances of winter survival than those exhibiting lower metabolic performance. In this study, we calculated repeatability to evaluate temporal consistency of body mass, BMR and Msum within and across three consecutives winters in black-capped chickadees (Poecile atricapillus). We found that body mass was significantly repeatable both within and across winters (R 0.51-0.90). BMR (R 0.29-0.47) was only repeatable within winter while Msum was repeatable both among (R 0.33-0.49) and within winters (R 0.33-0.49) with the magnitude and significance of repeatability in both variables depending on the year and whether they were corrected for body mass or body size. The patterns of repeatability observed among years also differed between the two variables. Our findings suggest that the relative ranking of individuals in winter metabolic performance is affected by local ecological conditions and can change within relatively short periods of time. J. Exp. Zool. 323A: 179-190, 2015. 2015 Wiley Periodicals, Inc. PMID:25690265

  9. Flexible Sigmoidoscopy - Gut-Check

    Cancer.gov

    The combination of a flexible sigmoidoscopy with a home stool test is an effective way to look for polyps and early cancer. Polyps are small growths that could become cancer one day. The flexible sigmoidoscopy only looks at part of the colon. It requires no sedation and a relatively simple prep. The procedure can be performed by some primary care doctors and gastroenterologists, but not all doctors perform the procedure regularly.

  10. Permeability measurement and scan imaging to assess clogging of pervious concrete pavements in parking lots.

    PubMed

    Kayhanian, Masoud; Anderson, Dane; Harvey, John T; Jones, David; Muhunthan, Balasingam

    2012-03-01

    This paper describes a study that used permeability measurement along with physical and hydrological characteristics of 20 pervious concrete pavements in parking lots throughout California. The permeability was measured at five locations: the main entrance, an area with no traffic, and three separate measurements within a parking space at each parking lot. Hydrological and physical site characteristics such as traffic flow, erosion, vegetation cover, sediments accumulation, maintenance practice, presence of cracking, rainfall, and temperature data were also collected for each parking lot. These data were used to perform detailed statistical analysis to determine factors influencing changes in permeability and hence assessing possible cause of clogging. In addition, seven representative core samples were obtained from four different parking lots with permeability ranging from very low to very high. Porosity profiles produced from CT scanning were used to assess the possible nature and extent of clogging. Results showed that there is a large variation in permeability within each parking lot and between different parking lots. In general, the age of the parking lot is the predominant factor influencing the permeability. Statistical analysis revealed that fine sediment (particles less than 38 ?m) mass is also an important influencing factor. Other influencing factors with lower significance included number of days with a temperature greater than 30C and the amount of vegetation next to the parking lot. The combined scanned image analysis and porosity profile of the cores showed that most clogging occurs near the surface of the pavement. While lower porosity generally appeared to be limited to the upper 25 mm, in some core samples evidence of lower porosity was found up to 100mm below the surface. PMID:22115516

  11. Evaluation of western and eastern shale oil residua as asphalt pavement recycling agents

    SciTech Connect

    Harnsberger, P.M.; Robertson, R.E.

    1990-03-01

    The objective of this investigation was to perform a preliminary evaluation of the utility of residual materials prepared from Green River Formation (western) and New Albany Shale (eastern) shale oils as recycling agents for aged asphalt pavement. Four petroleum asphalts were first aged by a thin-film accelerated-aging test, which simulates long service life of asphalt in pavement. The aged asphalts were mixed (recycled) with Green River Formation shale oil distillation residua to restore the original viscosities. Separately, for comparison, a commercial recycling agent was used to recycle the aged asphalts under the same circumstances. The recycled asphalts were reaged and the properties of both binder and asphalt-aggregate mixtures studied. Originally, the same study was intended for an eastern shale residua. However, the eastern shale oil distillation residua with the required flash point specification also had the properties of a viscosity builder; therefore, it was studied as such with asphalts that do not achieve sufficient viscosity during processing to serve as usable binders. Results show that Green River Formation shale oil residuum can be used to restore the original asphalt properties with favorable rheological properties, the shale oil residuum has a beneficial effect on resistance to moisture damage, the low-temperature properties of the shale oil residuum recycled asphalts are not adversely affected, and the low-temperature properties of the shale oil residuum recycled asphalts are dependent upon the chemistry of the mixture. The eastern shale oil residua was blended with soft petroleum asphalts. Results show the products have higher viscosities than the starting materials, the rheological properties of the soft asphalt-eastern shale oil residue blends are acceptable, and the eastern shale oil residue has dispersant properties despite its high viscosity. 11 refs., 3 figs., 9 tabs.

  12. Valuing flexibilities in the design of urban water management systems.

    PubMed

    Deng, Yinghan; Cardin, Michel-Alexandre; Babovic, Vladan; Santhanakrishnan, Deepak; Schmitter, Petra; Meshgi, Ali

    2013-12-15

    Climate change and rapid urbanization requires decision-makers to develop a long-term forward assessment on sustainable urban water management projects. This is further complicated by the difficulties of assessing sustainable designs and various design scenarios from an economic standpoint. A conventional valuation approach for urban water management projects, like Discounted Cash Flow (DCF) analysis, fails to incorporate uncertainties, such as amount of rainfall, unit cost of water, and other uncertainties associated with future changes in technological domains. Such approach also fails to include the value of flexibility, which enables managers to adapt and reconfigure systems over time as uncertainty unfolds. This work describes an integrated framework to value investments in urban water management systems under uncertainty. It also extends the conventional DCF analysis through explicit considerations of flexibility in systems design and management. The approach incorporates flexibility as intelligent decision-making mechanisms that enable systems to avoid future downside risks and increase opportunities for upside gains over a range of possible futures. A water catchment area in Singapore was chosen to assess the value of a flexible extension of standard drainage canals and a flexible deployment of a novel water catchment technology based on green roofs and porous pavements. Results show that integrating uncertainty and flexibility explicitly into the decision-making process can reduce initial capital expenditure, improve value for investment, and enable decision-makers to learn more about system requirements during the lifetime of the project. PMID:24268059

  13. Performance improvement of flexible bulk heterojunction solar cells using PTB7:PC71BM by optimizing spin coating and drying processes

    NASA Astrophysics Data System (ADS)

    Ohzeki, Masaya; Fujii, Shunjiro; Arai, Yuki; Yanagidate, Tatsuki; Yanagi, Yuichiro; Okukawa, Takanori; Yoshida, Akira; Kataura, Hiromichi; Nishioka, Yasushiro

    2014-02-01

    Bulk-heterojunction solar cells were fabricated using a dichlorobenzene solution of poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b?]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7):[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) on a flexible indium-tin-oxide-coated polyethylene terephthalate substrate. It was found that the performance of the solar cells could be markedly improved by minimizing the spin coating time of a blend of PTB7 and PC71BM to 10 s and maximizing the successive drying and solidification time up to 30 min in a confined Petri dish. As a result, a short-circuit current density of 14.5 mA/cm2, an open-circuit voltage of 0.62 V, and a power conversion efficiency of 3.67% were obtained. These improvements are attributed to the growth of favorable nanostructures during the slow drying process that increased the photocarrier collection efficiency while simultaneously increasing the performance fluctuations of each device.

  14. Electrodeposition of nickel sulfide on graphene-covered make-up cotton as a flexible electrode material for high-performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Li, Yiju; Ye, Ke; Cheng, Kui; Yin, Jinling; Cao, Dianxue; Wang, Guiling

    2015-01-01

    In this report, graphene nanosheets (GNS)/nickel sulfide (NiS) based material for high-performance supercapacitor is prepared by 'dip and dry' and electrodeposition methods. Commercial flexible make-up cottons (MCs) are chose as skeletons to construct homogeneous three-dimensional (3D) interconnected graphene-wrapped macro-networks, which can support structures for high loading of active electrode materials and facilitate the access of electrolytes to active electrode materials. The hybrid GNS/NiS based MCs (denoted as MCs@GNS@NiS) electrode yields relatively high specific capacitance of 775Fg-1 at a charge/discharge specific current of 0.5Ag-1 and good capacitance retention of 88.1% after 1000 cycles at 2Ag-1. Furthermore, the MCs@GNS@NiS electrode delivers a high energy density of 11.2Whkg-1 at even a high power density of 1008Wkg-1. Therefore, such low-cost and high-performance energy MCs based on GNS/NiS hierarchical nanostructures offer great promise in large-scale energy storage device applications.

  15. High-performance all-solid-state flexible micro-supercapacitor arrays with layer-by-layer assembled MWNT/MnO(x) nanocomposite electrodes.

    PubMed

    Lee, Geumbee; Kim, Daeil; Yun, Junyeong; Ko, Yongmin; Cho, Jinhan; Ha, Jeong Sook

    2014-08-21

    In this study, we report on the fabrication of high performance planar-type flexible micro-supercapacitor (MSC) arrays using Au electrodes coated with a functionalized multi-walled carbon nanotube (MWNT) film and a layer of MWNT-COOH/MnOx nanoparticle (NP) composite on top. The MWNT thin film was formed via layer-by-layer (LbL) assembly of MWNTs functionalized with amine groups and MWNTs with carboxylic acid groups in water. The hydrothermally synthesized composite of MWNT-COOH/MnOx NPs was coated on top of the MWNT film (LbL-MWNT). The addition of MWNT-COOH/MnOx NP composite as a top layer enhanced the performance of the MSCs dramatically, resulting in a volumetric capacitance of 50 F cm(-3) at a scan rate of 10 mV s(-1) and a coulombic efficiency of ?100%. By contrast, a volumetric capacitance of 3.6 F cm(-3) was obtained when using only the LbL-MWNT film. After repetitive operation up to ?10(4) times, the capacitance remained at ?88.3% of the original value. With a deliberate circuit design consisting of serially connected MSC arrays, various light-emitting diodes operating at different bias voltages could be lit. The MSC circuit fabricated on a polyethylene terephthalate (PET) film showed stable electrochemical properties upon 1000 cycles of bending deformation. PMID:24990386

  16. Effect of Permittivity and Permeability of a Flexible Magnetic Composite Material on the Performance and Miniaturization Capability of Planar Antennas for RFID and Wearable Wireless Applications

    Microsoft Academic Search

    Lara J. Martin; Sooliam Ooi; Daniela Staiculescu; Michael D. Hill; C. P. Wong; Manos M. Tentzeris

    2009-01-01

    This paper is an investigation of the feasibility of applying a mechanically flexible magnetic composite material to radio frequency identification (RFID) planar antennas operating in the lower ultrahigh-frequency (UHF) spectrum (~300500 MHz). A key challenge is that the magnetic loss introduced by the magnetic composite must be sufficiently low for successful application at the targeted operating frequency. A flexible magnetic

  17. An Overview Of Pavement Management System For Industrial Areas

    NASA Astrophysics Data System (ADS)

    Hokam, Vivek S.

    2012-03-01

    ACT With the current surge in national economy the industrial traffic has increased many folds in terms of quantity of load and traffic volume. This results in early deterioration of the roads. Also the serviceability reduces hampering the industry's supply of raw material and transport of finished goods. An efficient road transportation system is of vitally important for smooth operations of industrial units. Construction of new roads needs an enormous investment. However, once constructed the road network system requires huge resources to maintain serviceability and to ensure safe passage at an appropriate speed and with low VOC (Vehicle Operating Cost). Road maintenance is therefore an essential function and should be carried out on a timely basis. The cost of providing and maintaining the roads for the industrial areas at an acceptable serviceability level is quite high. It is therefore essential for a transportation engineer to attempt establishing an acceptable pavement condition level from economic, safety and environmental point of view. In today's economic environment of constrained budgets, as the existing road infrastructure has aged, a more systematic approach towards determining maintenance and rehabilitation needs is necessary. The efficient pavement management system shall provide objective information and useful analysis to ensure consistent and cost effective decisions related to preservation of existing industrial road network in healthy condition.

  18. One-dimensional semiconductor nanostructure based thin-film partial composite formed by transfer implantation for high-performance flexible and printable electronics at low temperature.

    PubMed

    Moon, Kyeong-Ju; Lee, Tae-Il; Choi, Ji-Hyuk; Jeon, Joohee; Kang, Youn Hee; Kar, Jyoti Prakash; Kang, Jung Han; Yun, Ilgu; Myoung, Jae-Min

    2011-01-25

    Having high bending stability and effective gate coupling, the one-dimensional semiconductor nanostructures (ODSNs)-based thin-film partial composite was demonstrated, and its feasibility was confirmed through fabricating the Si NW thin-film partial composite on the poly(4-vinylphenol) (PVP) layer, obtaining uniform and high-performance flexible field-effect transistors (FETs). With the thin-film partial composite optimized by controlling the key steps consisting of the two-dimensional random dispersion on the hydrophilic substrate of ODSNs and the pressure-induced transfer implantation of them into the uncured thin dielectric polymer layer, the multinanowire (NW) FET devices were simply fabricated. As the NW density increases, the on-current of NW FETs increases linearly, implying that uniform NW distribution can be obtained with random directions over the entire region of the substrate despite the simplicity of the drop-casting method. The implantation of NWs by mechanical transfer printing onto the PVP layer enhanced the gate coupling and bending stability. As a result, the enhancements of the field-effect mobility and subthreshold swing and the stable device operation up to a 2.5 mm radius bending situation were achieved without an additional top passivation. PMID:21174391

  19. Rigid-Flexible Coupling High Ionic Conductivity Polymer Electrolyte for an Enhanced Performance of LiMn2O4/Graphite Battery at Elevated Temperature.

    PubMed

    Hu, Pu; Duan, Yulong; Hu, Deping; Qin, Bingsheng; Zhang, Jianjun; Wang, Qingfu; Liu, Zhihong; Cui, Guanglei; Chen, Liquan

    2015-03-01

    LiMn2O4-based batteries exhibit severe capacity fading during cycling or storage in LiPF6-based liquid electrolytes, especially at elevated temperatures. Herein, a novel rigid-flexible gel polymer electrolyte is introduced to enhance the cyclability of LiMn2O4/graphite battery at elevated temperature. The polymer electrolyte consists of a robust natural cellulose skeletal incorporated with soft segment poly(ethyl ?-cyanoacrylate). The introduction of the cellulose effectively overcomes the drawback of poor mechanical integrity of the gel polymer electrolyte. Density functional theory (DFT) calculation demonstrates that the poly(ethyl ?-cyanoacrylate) matrices effectively dissociate the lithium salt to facilitate ionic transport and thus has a higher ionic conductivity at room temperature. Ionic conductivity of the gel polymer electrolyte is 3.3 10(-3) S cm(-1) at room temperature. The gel polymer electrolyte remarkably improves the cycling performance of LiMn2O4-based batteries, especially at elevated temperatures. The capacity retention after the 100th cycle is 82% at 55 C, which is much higher than that of liquid electrolyte (1 M LiPF6 in carbonate solvents). The polymer electrolyte can significantly suppress the dissolution of Mn(2+) from surface of LiMn2O4 because of strong interaction energy of Mn(2+) with PECA, which was investigated by DFT calculation. PMID:25654192

  20. High-performance all-solid-state flexible micro-supercapacitor arrays with layer-by-layer assembled MWNT/MnOx nanocomposite electrodes

    NASA Astrophysics Data System (ADS)

    Lee, Geumbee; Kim, Daeil; Yun, Junyeong; Ko, Yongmin; Cho, Jinhan; Ha, Jeong Sook

    2014-07-01

    In this study, we report on the fabrication of high performance planar-type flexible micro-supercapacitor (MSC) arrays using Au electrodes coated with a functionalized multi-walled carbon nanotube (MWNT) film and a layer of MWNT-COOH/MnOx nanoparticle (NP) composite on top. The MWNT thin film was formed via layer-by-layer (LbL) assembly of MWNTs functionalized with amine groups and MWNTs with carboxylic acid groups in water. The hydrothermally synthesized composite of MWNT-COOH/MnOx NPs was coated on top of the MWNT film (LbL-MWNT). The addition of MWNT-COOH/MnOx NP composite as a top layer enhanced the performance of the MSCs dramatically, resulting in a volumetric capacitance of 50 F cm-3 at a scan rate of 10 mV s-1 and a coulombic efficiency of ~100%. By contrast, a volumetric capacitance of 3.6 F cm-3 was obtained when using only the LbL-MWNT film. After repetitive operation up to ~104 times, the capacitance remained at ~88.3% of the original value. With a deliberate circuit design consisting of serially connected MSC arrays, various light-emitting diodes operating at different bias voltages could be lit. The MSC circuit fabricated on a polyethylene terephthalate (PET) film showed stable electrochemical properties upon 1000 cycles of bending deformation.In this study, we report on the fabrication of high performance planar-type flexible micro-supercapacitor (MSC) arrays using Au electrodes coated with a functionalized multi-walled carbon nanotube (MWNT) film and a layer of MWNT-COOH/MnOx nanoparticle (NP) composite on top. The MWNT thin film was formed via layer-by-layer (LbL) assembly of MWNTs functionalized with amine groups and MWNTs with carboxylic acid groups in water. The hydrothermally synthesized composite of MWNT-COOH/MnOx NPs was coated on top of the MWNT film (LbL-MWNT). The addition of MWNT-COOH/MnOx NP composite as a top layer enhanced the performance of the MSCs dramatically, resulting in a volumetric capacitance of 50 F cm-3 at a scan rate of 10 mV s-1 and a coulombic efficiency of ~100%. By contrast, a volumetric capacitance of 3.6 F cm-3 was obtained when using only the LbL-MWNT film. After repetitive operation up to ~104 times, the capacitance remained at ~88.3% of the original value. With a deliberate circuit design consisting of serially connected MSC arrays, various light-emitting diodes operating at different bias voltages could be lit. The MSC circuit fabricated on a polyethylene terephthalate (PET) film showed stable electrochemical properties upon 1000 cycles of bending deformation. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr02035a

  1. DNA Flexibility

    NASA Astrophysics Data System (ADS)

    Widom, Jonathan

    2005-03-01

    Classic experimental and theoretical analyses led to a unified view of DNA as a semiflexible polymer, characterized by a bending persistence length, P, 50 nm (150 bp). In this view, DNA lengths that are greater than P are, on average, spontaneously gently bent, and require relatively little force to bend significantly, while DNA lengths that are shorter than P are nearly straight, and require great force to bend significantly. Nevertheless, sharply bent DNA plays important roles in biology. We used the method of ligase catalyzed DNA cyclization to investigate the spontaneous looping of short DNAs. Remarkably, DNAs as short as 84 bp spontaneously bend into circles, and 94 bp DNA sequences cyclize up to 10^5 times more easily than predicted from classic theories of DNA bending. In subsequent studies we find that the twistability of sharply looped DNAs exceeds the prediction of classic theories by up to 400-fold. These results can only be understood by greatly enhanced DNA flexibility, not by permanent bends. Our results provide striking support for two new theories of DNA mechanics based on local melted or kinked regions, and they establish DNA as an active participant in the formation and function of looped regulatory complexes in vivo.

  2. Flexible rotor dynamics analysis

    NASA Technical Reports Server (NTRS)

    Shen, F. A.

    1973-01-01

    A digital computer program was developed to analyze the general nonaxisymmetric and nonsynchronous transient and steady-state rotor dynamic performance of a bending- and shear-wise flexible rotor-bearing system under various operating conditions. The effects of rotor material mechanical hysteresis, rotor torsion flexibility, transverse effects of rotor axial and torsional loading and the anisotropic, in-phase and out-of-phase bearing stiffness and damping force and moment coefficients were included in the program to broaden its capability. An optimum solution method was found and incorporated in the computer program. Computer simulation of experimental data was made and qualitative agreements observed. The mathematical formulations, computer program verification, test data simulation, and user instruction was presented and discussed.

  3. The effect of carbonation after demolition on the life cycle assessment of pavements

    E-print Network

    Rossick, Katelyn M

    2014-01-01

    The high contribution of CO? emissions associated with pavements has driven research to assess the life cycle of concrete versus asphalt structures and to develop a strategy to reduce the carbon footprint. The life cycle ...

  4. Assessment of Clogging Dynamics in Permeable Pavement Systems with Time Domain Reflectometers

    EPA Science Inventory

    Infiltration is a primary functional mechanism in green infrastructure stormwater controls. This study used time domain reflectometers (TDRs) to measure spatial infiltration and assess clogging dynamics of permeable pavement systems in Edison, NJ, and Louisville, KY. In 2009, t...

  5. Effect of pervious and impervious pavement on the rhizosphere of American Sweetgum (Liquidambar styraciflua)

    E-print Network

    Viswanathan, Bhavana

    2012-07-16

    Mature trees help to offset urban area problems caused by impervious pavement. Trees in paved areas remain unhealthy due to a poor root zone environment. The objective of this experiment was to test if soil under pervious concrete, with greater...

  6. Surface control of desert pavement pedologic process and landscape function, Cima Volcanic field,

    E-print Network

    Ahmad, Sajjad

    Surface control of desert pavement pedologic process and landscape function, Cima Volcanic field of the land surfaces it mantles. Surface clasts protect underlying sediments and soil from removal by wind

  7. PHYSIOLOGICAL INFORMATION FOR PAVEMENT HEALTH MONITORING BASED ON SURFACE RIDE QUALITY

    NASA Astrophysics Data System (ADS)

    Tomiyama, Kazuya; Kawamura, Akira; Takahashi, Kiyoshi; Ishida, Tateki

    Pavement ride quality testing has traditionally been based on subjective questionnaire ratings. The questionnaire survey has ability to directly measure the sense of road users' ride quality. However, it is difficult to quantify the evaluation results based on the questionnaire due to its lack of objectivity. This study examines pavement health monitoring method using physiological information such as heart rate variability (HRV) for detecting mental stress of road users toward pavement ride quality. First, a results of a driving simulator experiment shows that potential mental stress caused by road roughness can be observed in high-frequency oscillations in 0.15-0.4Hz of HRV processed by continuous wavelet transform. Then, the high-frequency oscillations of HRV is summarized as an index related to the mental stress that makes objective ride quality evaluation possible. Finally, this study indicates that the index contributes to improve the accuracy of pavement health monitoring based on surface ride quality.

  8. Development of a Prediction Model for Skid Resistance of Asphalt Pavements

    E-print Network

    Rezaei, Arash

    2012-02-14

    surface. Microtexture is influenced by aggregate surface characteristics and is required to disrupt the continuity of surface water film and attain frictional resistance between the tire and the pavement surface. Macrotexture is affected mostly by mixture...

  9. The impact of maintenance and rehabilitation strategies on the pavement network value

    E-print Network

    Chang Albitres, Carlos Martin

    1999-01-01

    The maintenance and rehabilitation of road infrastructure demands a great investment of time and money. The deterioration of pavement condition over time due to environmental factors and increasing traffic loads combined with the limitation of funds...

  10. Validation and development of guidelines to select MRR strategies for rigid pavements

    E-print Network

    Herrera, Edgar Efren

    2001-01-01

    Maintenance, rehabilitation and reconstruction (MRR) work to rigid pavement roadways requires a great demand of time, effort, and money. The nature of this work not only affects state highway agencies (SHAs) but also, roadway users and local...

  11. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...HIGHWAYS NATIONAL PARK SERVICE MANAGEMENT SYSTEMS National Park Service Management Systems 970.208 Federal lands pavement management system (PMS). In addition...framework for a PMS: (1) A database and an ongoing program...

  12. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...HIGHWAYS NATIONAL PARK SERVICE MANAGEMENT SYSTEMS National Park Service Management Systems 970.208 Federal lands pavement management system (PMS). In addition...framework for a PMS: (1) A database and an ongoing program...

  13. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...HIGHWAYS NATIONAL PARK SERVICE MANAGEMENT SYSTEMS National Park Service Management Systems 970.208 Federal lands pavement management system (PMS). In addition...framework for a PMS: (1) A database and an ongoing program...

  14. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...HIGHWAYS NATIONAL PARK SERVICE MANAGEMENT SYSTEMS National Park Service Management Systems 970.208 Federal lands pavement management system (PMS). In addition...framework for a PMS: (1) A database and an ongoing program...

  15. Field observations and numerical models of GPR response from vertical pavement cracks

    NASA Astrophysics Data System (ADS)

    Diamanti, Nectaria; Redman, David

    2012-06-01

    High resolution ground-coupled GPR is useful for determining thickness, deterioration, jointing and cracks in pavements. Although only millimetres in width, vertical cracks can present a significant target in reflection profiles. On composite pavements, consisting of asphalt over concrete, we have observed responses at locations above joints in the underlying concrete that we attribute to cracks within the asphalt layer. On some asphalt pavement, we observed significantly stronger diffraction and waveguide effects responses at a 250 MHz centre frequency rather than at 1000 MHz, despite the small crack apertures. Using numerical modelling we show the importance of crack filling material, crack aperture, crack height, asphalt conductivity and the GPR centre frequency on the observed response. Our observations and models clearly show the potential of GPR to detect and characterise vertical cracks. We recommend a multi-frequency approach to GPR surveys of pavement: high frequency for crack characterisation and lower frequency for crack detection.

  16. Techniques to Determine Maintenace Frequency of Permeable Pavement Systems with Time Domain Reflectometers (TDRs

    EPA Science Inventory

    As the surface clogs in permeable pavement systems, they lose effectiveness and require maintenance. There is limited direct guidance for determining when maintenance is needed to prevent surface runoff bypass. Research is being conducted using multiple time domain reflectomete...

  17. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...HIGHWAYS NATIONAL PARK SERVICE MANAGEMENT SYSTEMS National Park Service Management Systems 970.208 Federal lands pavement management system (PMS). In addition...framework for a PMS: (1) A database and an ongoing program...

  18. The role of urban surfaces (permeable pavements) in regulating drainage and evaporation: development of a laboratory simulation experiment

    NASA Astrophysics Data System (ADS)

    Andersen, C. T.; Foster, I. D. L.; Pratt, C. J.

    1999-03-01

    Permeable pavements and similar stormwater control devices have not been exploited in the UK, in part because their adoption has been hindered by a lack of detailed knowledge of their hydrological performance. This paper describes a research programme that produced detailed information on the hydrological behaviour of a car park surface. The study involved the construction of full-scale permeable pavement model car park structures and a rainfall simulator for use in the laboratory. A monitoring procedure was developed in order to measure inputs and changes in drainage, storage and evaporation over short and long time-scales (2 hours to 3 months). A range of simulated rainfalls, which varied in intensity and duration, was applied to the model car park surfaces. Hydrological processes were monitored over an 18-month period. Results demonstrated that evaporation, drainage and retention in the structures were strongly influenced by the particle size distribution of the bedding material and by water retention in the surface blocks. In general, an average of 55% of a one-hour duration, 15 mm h-1 rainfall event could be retained by an initially air-dry structure. Subsequent simulations demonstrated that 30% of a one-hour duration, 15 mm h-1 rainfall event could be stored by an initially wet structure (with a minimum time interval between rainfall applications of 72 hours).

  19. Contribution of lateral processes to stone pavement formation in deserts inferred from clast orientation patterns

    NASA Astrophysics Data System (ADS)

    Dietze, Michael; Kleber, Arno

    2012-02-01

    Stone pavements are widespread landforms of arid environments. They typically develop by accretionary rise above a thickening aeolian mantle which usually contains a surficial vesicular unit. Hence, stone pavements are regarded as stable landforms and, thus, are often used as surface-age indicators. We studied orientation patterns of pavement clasts and depict their geometrical properties. We introduce a new statistical approach for quantitative description of circular data. From four study regions in a wide variety of environmental settings we show that preferred, non-random orientation of clast length axes is a recurrent feature of modern stone pavements. Orientation is primarily determined by no other relief parameter than slope aspect. In 40 out of 52 measured plots an angle of 72 9 separates two angle maxima. The same patterns are present in stone lines buried under a cover of aeolian dust. We interpret these features as fossil stone pavements, accordingly. Furthermore, on artificially cleared plots disturbed stone pavements begin to recover within few months by a process which creates essentially the same orientation pattern. We suggest that lateral surficial processes such as unconcentrated overland flow and creep contribute to the formation and maintenance of stone pavements as well as to this preferred clast orientation. They arrange clasts symmetrical to slope aspect with an angle determined by the axes ratio of the transported object. This results in the frequent bimodal pattern of stone length axes. This special type of transport requires previous accumulation of aeolian material forming a fine grained, even vesicular layer. Thus, there is close relationship between stone pavement and vesicular layer. We conclude that lateral processes take part in stone pavement formation. The commonly accepted model of dust accretion, which is not rendered obsolete by our findings, has to be complemented by this lateral component. This has implications for the stability of stone pavement-covered surfaces and for their applicability as age indicators. Quickly resealing disturbances as well as fossilised stone pavements imply this prominent desert surface feature may become fragile and transient.

  20. Oxidative reactions and their impact on the properties of asphalt as a pavement binder

    E-print Network

    Lau, Chee Keung

    1991-01-01

    of MASTER OF SCIENCE December 1991 Major Subject: Chemical Engineering OXIDATIVE REACTIONS AND THEIR IMPACT ON THE PROPERTIES OF ASPHALT AS A PAVEMENT BINDER A Thesis by CHEE KEUNG LAU Approved as to style and content by: Charles J. over (Chair... of Committee) Rich d R. Davison (Member) i ( Alan Letton (Member) Raymond W. umerfelt (Head of Department) December, 1991 111 Oxidative Reactions and Their Impact on the Properties of Asphalt as a Pavement Binder. (December 1991) Chee Keung Lau, B...